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Freshwater Fisheries Ecology

Freshwater Fisheries EcologyEdited by

John F CraigCraig Consultancy Dumfries Scotland UK

This edition first published 2016 copy 2016 by John Wiley amp Sons Ltd

Registered Office John Wiley amp Sons Ltd The Atrium Southern Gate Chichester West Sussex PO19 8SQ UK

Editorial Offices 960 Garsington Road Oxford OX4 2DQ UKThe Atrium Southern Gate Chichester West Sussex PO19 8SQ UK111 River Street Hoboken NJ 07030-5774 USA

For details of our global editorial offices for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at wwwwileycomwiley-blackwell

The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright Designs and Patents Act 1988

All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise except as permitted by the UK Copyright Designs and Patents Act 1988 without the prior permission of the publisher

Designations used by companies to distinguish their products are often claimed as trademarks All brand names and product names used in this book are trade names service marks trademarks or registered trademarks of their respective owners The publisher is not associated with any product or vendor mentioned in this book

Limit of LiabilityDisclaimer of Warranty While the publisher and author(s) have used their best efforts in preparing this book they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom If professional advice or other expert assistance is required the services of a competent professional should be sought

Library of Congress Cataloging-in-Publication Data

Freshwater fisheries ecology edited by John F Craig pages cm Includes index ISBN 978-1-118-39442-7 (cloth)1 Fisheries 2 Freshwater ecology I Craig John F editor SH331F786 2015 6392ndashdc23

2015006684

A catalogue record for this book is available from the British Library

Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books

Set in 9512pt Minion by SPi Global Pondicherry India

1 2016

Freshwater Fisheries Ecology

Freshwater Fisheries EcologyEdited by

John F CraigCraig Consultancy Dumfries Scotland UK

This edition first published 2016 copy 2016 by John Wiley amp Sons Ltd

Registered Office John Wiley amp Sons Ltd The Atrium Southern Gate Chichester West Sussex PO19 8SQ UK

Editorial Offices 960 Garsington Road Oxford OX4 2DQ UKThe Atrium Southern Gate Chichester West Sussex PO19 8SQ UK111 River Street Hoboken NJ 07030-5774 USA

For details of our global editorial offices for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at wwwwileycomwiley-blackwell

The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright Designs and Patents Act 1988

All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise except as permitted by the UK Copyright Designs and Patents Act 1988 without the prior permission of the publisher

Designations used by companies to distinguish their products are often claimed as trademarks All brand names and product names used in this book are trade names service marks trademarks or registered trademarks of their respective owners The publisher is not associated with any product or vendor mentioned in this book

Limit of LiabilityDisclaimer of Warranty While the publisher and author(s) have used their best efforts in preparing this book they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom If professional advice or other expert assistance is required the services of a competent professional should be sought

Library of Congress Cataloging-in-Publication Data

Freshwater fisheries ecology edited by John F Craig pages cm Includes index ISBN 978-1-118-39442-7 (cloth)1 Fisheries 2 Freshwater ecology I Craig John F editor SH331F786 2015 6392ndashdc23

2015006684

A catalogue record for this book is available from the British Library

Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books

Set in 9512pt Minion by SPi Global Pondicherry India

1 2016

Freshwater Fisheries EcologyEdited by

John F CraigCraig Consultancy Dumfries Scotland UK

This edition first published 2016 copy 2016 by John Wiley amp Sons Ltd

Registered Office John Wiley amp Sons Ltd The Atrium Southern Gate Chichester West Sussex PO19 8SQ UK

Editorial Offices 960 Garsington Road Oxford OX4 2DQ UKThe Atrium Southern Gate Chichester West Sussex PO19 8SQ UK111 River Street Hoboken NJ 07030-5774 USA

For details of our global editorial offices for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at wwwwileycomwiley-blackwell

The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright Designs and Patents Act 1988

All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise except as permitted by the UK Copyright Designs and Patents Act 1988 without the prior permission of the publisher

Designations used by companies to distinguish their products are often claimed as trademarks All brand names and product names used in this book are trade names service marks trademarks or registered trademarks of their respective owners The publisher is not associated with any product or vendor mentioned in this book

Limit of LiabilityDisclaimer of Warranty While the publisher and author(s) have used their best efforts in preparing this book they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom If professional advice or other expert assistance is required the services of a competent professional should be sought

Library of Congress Cataloging-in-Publication Data

Freshwater fisheries ecology edited by John F Craig pages cm Includes index ISBN 978-1-118-39442-7 (cloth)1 Fisheries 2 Freshwater ecology I Craig John F editor SH331F786 2015 6392ndashdc23

2015006684

A catalogue record for this book is available from the British Library

Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books

Set in 9512pt Minion by SPi Global Pondicherry India

1 2016

This edition first published 2016 copy 2016 by John Wiley amp Sons Ltd

Registered Office John Wiley amp Sons Ltd The Atrium Southern Gate Chichester West Sussex PO19 8SQ UK

Editorial Offices 960 Garsington Road Oxford OX4 2DQ UKThe Atrium Southern Gate Chichester West Sussex PO19 8SQ UK111 River Street Hoboken NJ 07030-5774 USA

For details of our global editorial offices for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at wwwwileycomwiley-blackwell

The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright Designs and Patents Act 1988

All rights reserved No part of this publication may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical photocopying recording or otherwise except as permitted by the UK Copyright Designs and Patents Act 1988 without the prior permission of the publisher

Designations used by companies to distinguish their products are often claimed as trademarks All brand names and product names used in this book are trade names service marks trademarks or registered trademarks of their respective owners The publisher is not associated with any product or vendor mentioned in this book

Limit of LiabilityDisclaimer of Warranty While the publisher and author(s) have used their best efforts in preparing this book they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom If professional advice or other expert assistance is required the services of a competent professional should be sought

Library of Congress Cataloging-in-Publication Data

Freshwater fisheries ecology edited by John F Craig pages cm Includes index ISBN 978-1-118-39442-7 (cloth)1 Fisheries 2 Freshwater ecology I Craig John F editor SH331F786 2015 6392ndashdc23

2015006684

A catalogue record for this book is available from the British Library

Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books

Set in 9512pt Minion by SPi Global Pondicherry India

1 2016

For the future generation Benjamin Hugh Toby Charlie Barnaby Penelope and Flora

vii

List of contributors x

Foreword xiv

Preface xv

Acknowledgements xvi

Section 1 Freshwater fisheries ecology

11 Introduction 3John F Craig

Section 2 Freshwater ecosystems

21 Introduction 7John F Craig

22 The dynamics of rivers in relation to fishes and fisheries 9Geoff Petts Marie‐Pierre Gosselin and Janina Gray

23 The dynamics of lakes in relation to fishes and fisheries 31Brian Moss

24 The physico‐chemical characteristics biota and fisheries of estuaries 48Ian C Potter Richard M Warwick Norm G Hall and James R Tweedley

Section 3 Freshwater resources

31 Introduction 83John F Craig

32 Northern North America 85Wiliam Tonn Heidi Swanson Cynthia Paszkowski Justin Hanisch and Louise Chavarie

33 Fennoscandian freshwater fishes diversity use threats and management 101Bror Jonsson and Nina Jonsson

34 Fishery and freshwater ecosystems of Russia status trends research management and priorities 120Yury Yu Dgebuadze

35 Fishery of the Laurentian Great Lakes 134Thomas E Lauer

36 Canadian freshwater fishes fisheries and their management south of 60degN 151John R Post Nicholas Mandrak and Mary Burridge

37 Freshwater fisheries of the United States 166Thomas E Lauer and Mark Pyron

38 Fisheries in the densely populated landscapes of Western Europe 181Ian J Winfield and Daniel Gerdeaux

39 Freshwater resources and fisheries in Slovakia 191Andrea Novomeskaacute and Vladimiacuter Kovaacuteč

310 Freshwater resources and fisheries in Hungary 196Andraacutes Specziaacuter and Tibor Erős

311 Freshwater resources and fisheries in the Czech Republic 201Pavel Horkyacute

312 Problems and challenges of fish stock management in fresh waters of Poland 208Zbigniew Kaczkowski and Joanna Grabowska

313 Nature and status of freshwater fisheries in Belarus 216Vitaliy Semenchenko Victor Rizevski and Inna Ermolaeva

314 Current state of freshwater fisheries in China 221Yahui Zhao Rodolphe Elie Gozlan and Chunguang Zhang

315 Japanese inland fisheries and aquaculture status and trends 231Osamu Katano Hiroshi Hakoyama and Shin‐ichiro S Matsuzaki

316 Fisheries in subtropical and temperate regions of Africa 241Olaf L F Weyl and Paul D Cowley

317 Freshwater fisheries resources in subtropical America 256Rafael Miranda

318 Iberian inland fisheries 268Carlos Antunes Fernando Cobo and Maacuterio Jorge Arauacutejo

319 Nature and status of freshwater and estuarine fisheries in Italy and Western Balkans 283Pier Giorgio Bianco and Valerio Ketmaier

Contents

viii Contents

320 Fisheries ecology of Greece 292Ioannis D Leonardos

321 The ecology of inland fisheries of Turkey 304Sedat V Yerli

322 Fisheries ecology in South American river basins 311Maacuterio Barletta Victor E Cussac Angelo A Agostinho Claudio Baiguacuten Edson K Okada Agostinho Carlos Catella Nelson F Fontoura Paulo S Pompeu Luz F Jimeacutenez‐Segura Vandick S Batista Carlos A Lasso Donald Taphorn and Niacutedia N Fabreacute

323 Inland fisheries of tropical Africa 349Brian E Marshall

324 Fisheries of the rivers of Southeast Asia 363Robin L Welcomme Ian G Baird David Dudgeon Ashley Halls Dirk Lamberts and Md Golam Mustafa

325 Asian upland fishes and fisheries 377A Ian Payne

326 Fishes and fisheries of Asian inland lacustrine waters 384Upali S Amarasinghe and Sena S De Silva

327 Freshwater fisheries of Australasia 404Donald J Jellyman Peter C Gehrke and John H Harris

Section 4 Fishing operations

41 Introduction 421John F Craig

42 Aboriginal freshwater fisheries as resilient socialndashecological systems 422Mimi E Lam

43 Commercial inland capture fisheries 438Devin M Bartley Gertjan de Graaf and John Valbo‐Joslashrgensen

44 Recreational fisheries in inland waters 449Steven J Cooke Robert Arlinghaus Brett M Johnson and Ian G Cowx

Section 5 Fisheries management

51 Fisheries governance and management 469Robin L Welcomme

52 Assessment and modelling in freshwater fisheries 483Tony J Pitcher

53 Social benefits from inland fisheries implications for a people‐centred response to management and governance challenges 500Robert Arthur Richard Friend and Christophe Beacuteneacute

54 A human rights‐based approach to securing livelihoods depending on inland fisheries 513Nicole Franz Carlos Fuentevilla Lena Westlund and Rolf Willmann

55 The optimal fishing pattern 524Jeppe Kolding Richard Law Michael Plank and Paul A M van Zwieten

Section 6 Fisheries development

61 Introduction 543John F Craig

62 Environmental assessment for fisheries 544Nigel Milner

63 Management of freshwater fisheries addressing habitat people and fishes 557Robert Arlinghaus Kai Lorenzen Brett M Johnson Steven J Cooke and Ian G Cowx

64 Aquaculture 580Randall E Brummett and Malcolm C M Beveridge

65 Ecological implications of genetically modified fishes in freshwater fisheries with a focus on salmonids 594L Fredrik Sundstroumlm and Robert H Devlin

66 Sustainable freshwater fisheries the search for workable solutions 616Rodolphe Elie Gozlan and John Robert Britton

Section 7 The effects of perturbations on fisheries

71 Introduction 625John F Craig

72 Harvest‐induced phenotypic change in inland fisheries 626Lauren J Chapman and Diana M T Sharpe

73 Climate change and freshwater fisheries 641Chris Harrod

74 Toxicology 695Nic Bury

75 Impoundments barriers and abstractions impact on fishes and fisheries mitigation and future directions 717Paul S Kemp

76 Role and impact of non‐native species on inland fisheries the Janus syndrome 770Rodolphe Elie Gozlan

77 Eutrophication and freshwater fisheries 779Ian J Winfield

Contents ix

78 Aquaculture and the environment 794Malcolm C M Beveridge and Randall E Brummett

Section 8 Tools and future developments in freshwater fisheries

81 Introduction 807John F Craig

82 A list of suggested research areas in freshwater fisheries ecology 808John F Craig

83 Molecular ecology and stock identification 811Eleanor A S Adamson and David A Hurwood

84 Recruitment 830Thomas A Johnston Nigel P Lester and Brian J Shuter

Countries index 846

Fish index 848

Author index 860

Subject index 884

x

Eleanor A S AdamsonDepartment of Life Sciences Natural History Museum London UK

Angelo A Agostinho Nupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Upali S AmarasingheDepartment of Zoology University of Kelaniya Kelaniya Sri Lanka

Carlos AntunesCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal Aquamuseu do Rio Minho Parque do Castelinho V N Cerveira Portugal and ESG ndash Escola Superior Gallaecia Largo das Oliveiras V N Cerveira Portugal

Maacuterio Jorge ArauacutejoCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal

Robert ArlinghausDepartment of Biology and Ecology of Fishes Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Berlin Germany and Faculty of Life Sciences Humboldt‐Universitaumlt zu Berlin Berlin Germany

Robert ArthurMRAG Ltd London UK

Claudio BaiguacutenInstituto Tecnologico de Chascomus Chascomus Argentina

Ian G BairdDepartment of Geography University of Wisconsin‐Madison Madison USA

Maacuterio BarlettaLaboratoacuterio de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos Departamento de Oceanografia Universidade Federal de Pernambuco Cidade Universitaacuteria Recife Brazil

Devin M BartleyFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Vandick S BatistaUniversidade Federal de Alagoas Maceioacute Brazil

Christophe BeacuteneacuteInternational Center for Tropical Agriculture (CIAT) Cali Colombia

Malcolm C M BeveridgeWorldFish Lusaka Zambia

Pier Giorgio BiancoBiological Department Zoological Section University of Naples Naples Italy

John Robert BrittonSchool of Applied Sciences Bournemouth University Dorset UK

Randall E BrummettWorld Bank Washington USA

Mary BurridgeRoyal Ontario Museum Toronto Canada

Nic BuryFaculty of Life Sciences and Medicine Division of Diabetes and Nutritional Sciences Kingrsquos College London UK

Agostinho Carlos CatellaRecursos Pesqueiros Embrapa Pantanal Empresa Brasileira de Pesquisa Agropecuaacuteria (Embrapa Pantanal) Corumbaacute Brazil

Lauren J ChapmanDepartment of Biology McGill University Montreacuteal Canada

Louise ChavarieDepartment of Biological Sciences University of Alberta Edmonton Canada

Fernando CoboDepartamento de Zoologiacutea y Antropologiacutea Fiacutesica Universidad de Santiago de Compostela Santiago de Compostela Spain and Estacioacuten de Hidrobiologiacutea ldquoEncoro do Conrdquo Castroagudiacuten sn Pontevedra Spain

Steven J CookeFish Ecology and Conservation Physiology Laboratory Institute of Environmental Science and Department of Biology Carleton University Ottawa Canada

Paul D CowleySouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Ian G CowxHull International Fisheries Institute Department of Biological Sciences The University of Hull Kingston‐upon‐Hull UK

John F CraigCraig Consultancy Dumfries Scotland UK

List of contributors

List of contributors xi

Victor E CussacInstituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) Universidad Nacional del Comahue (UNCO) ndash Consejo Nacional de Investigaciones Cientiacuteficas y Teacutecnicas (CONICET) Bariloche Argentina

Gertjan de GraafFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Sena S De SilvaSchool of Life and Environment Sciences Deakin University Warrnambool Campus Princes Highway Warrnambool Australia

Robert H DevlinFisheries and Oceans Canada West Vancouver Canada

Yury Yu DgebuadzeSevertsov Institute of Ecology amp Evolution Moscow Russia

David DudgeonSchool of Biological Sciences The University of Hong Kong Hong Kong China

Inna ErmolaevaScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Tibor ErosBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

Niacutedia N FabreacuteUniversidade Federal de Alagoas Maceioacute Brazil

Nelson F FontouraDepartamento de Biodiversidade e Ecologia Faculdade de Biociecircncias ndash PUCRS Porto Alegre Brazil

Nicole FranzFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Richard FriendInstitute for Social amp Environmental Transition (ISET) Bangkok Thailand

Carlos FuentevillaFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Peter C GehrkeOpus International Consultants Spring Hill Australia

Daniel GerdeauxINRA Thonon les Bains France

Marie‐Pierre GosselinStricklandgate Kendal UK

Rodolphe Elie GozlanUniteacute Mixte de Recherche Biologie des Organismes et Eacutecosystegravemes Aquatiques (Institut de Recherche pour le Deacuteveloppement 207 Centre National de la Recherche Scientifique 7208 Museacuteum National drsquoHistoire Naturelle Universiteacute Pierre et Marie Curie) Museacuteum National drsquoHistoire Naturelle Paris Cedex France

Joanna GrabowskaDepartment of Ecology and Vertebrate Zoology University of Łoacutedź Łoacutedź Poland

Janina GrayThe University of Westminster London UK

Hiroshi HakoyamaNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Norm G HallCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Ashley HallsAquae Sulis (Research) Ltd (ASL) Bradford‐on‐Avon Wiltshire UK

Justin HanischDepartment of Biological Sciences University of Alberta Edmonton Canada

John H HarrisCentre for Ecosystem Science UNSW Australia

Chris HarrodInstituto de Ciencias Naturales Alexander Von Humboldt Universidad de Antofagasta Antofagasta Chile

Pavel HorkyacuteDepartment of Zoology and Fisheries Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Prague Czech Republic

David A HurwoodScience and Engineering Faculty Queensland University of Technology Brisbane Australia

Donald J JellymanNational Institute of Water and Atmosphere Christchurch New Zealand

Luz F Jimeacutenez‐SeguraInstituto de Biologiacutea Universidad de Antioquia Medelliacuten Colombia

Brett M JohnsonDepartment of Fish Wildlife and Conservation Biology Colorado State University Fort Collins USA

Thomas A JohnstonOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Cooperative Freshwater Ecology Unit Vale Living with Lakes Centre Laurentian University Sudbury Canada

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

vii

List of contributors x

Foreword xiv

Preface xv

Acknowledgements xvi

Section 1 Freshwater fisheries ecology

11 Introduction 3John F Craig

Section 2 Freshwater ecosystems

21 Introduction 7John F Craig

22 The dynamics of rivers in relation to fishes and fisheries 9Geoff Petts Marie‐Pierre Gosselin and Janina Gray

23 The dynamics of lakes in relation to fishes and fisheries 31Brian Moss

24 The physico‐chemical characteristics biota and fisheries of estuaries 48Ian C Potter Richard M Warwick Norm G Hall and James R Tweedley

Section 3 Freshwater resources

31 Introduction 83John F Craig

32 Northern North America 85Wiliam Tonn Heidi Swanson Cynthia Paszkowski Justin Hanisch and Louise Chavarie

33 Fennoscandian freshwater fishes diversity use threats and management 101Bror Jonsson and Nina Jonsson

34 Fishery and freshwater ecosystems of Russia status trends research management and priorities 120Yury Yu Dgebuadze

35 Fishery of the Laurentian Great Lakes 134Thomas E Lauer

36 Canadian freshwater fishes fisheries and their management south of 60degN 151John R Post Nicholas Mandrak and Mary Burridge

37 Freshwater fisheries of the United States 166Thomas E Lauer and Mark Pyron

38 Fisheries in the densely populated landscapes of Western Europe 181Ian J Winfield and Daniel Gerdeaux

39 Freshwater resources and fisheries in Slovakia 191Andrea Novomeskaacute and Vladimiacuter Kovaacuteč

310 Freshwater resources and fisheries in Hungary 196Andraacutes Specziaacuter and Tibor Erős

311 Freshwater resources and fisheries in the Czech Republic 201Pavel Horkyacute

312 Problems and challenges of fish stock management in fresh waters of Poland 208Zbigniew Kaczkowski and Joanna Grabowska

313 Nature and status of freshwater fisheries in Belarus 216Vitaliy Semenchenko Victor Rizevski and Inna Ermolaeva

314 Current state of freshwater fisheries in China 221Yahui Zhao Rodolphe Elie Gozlan and Chunguang Zhang

315 Japanese inland fisheries and aquaculture status and trends 231Osamu Katano Hiroshi Hakoyama and Shin‐ichiro S Matsuzaki

316 Fisheries in subtropical and temperate regions of Africa 241Olaf L F Weyl and Paul D Cowley

317 Freshwater fisheries resources in subtropical America 256Rafael Miranda

318 Iberian inland fisheries 268Carlos Antunes Fernando Cobo and Maacuterio Jorge Arauacutejo

319 Nature and status of freshwater and estuarine fisheries in Italy and Western Balkans 283Pier Giorgio Bianco and Valerio Ketmaier

Contents

viii Contents

320 Fisheries ecology of Greece 292Ioannis D Leonardos

321 The ecology of inland fisheries of Turkey 304Sedat V Yerli

322 Fisheries ecology in South American river basins 311Maacuterio Barletta Victor E Cussac Angelo A Agostinho Claudio Baiguacuten Edson K Okada Agostinho Carlos Catella Nelson F Fontoura Paulo S Pompeu Luz F Jimeacutenez‐Segura Vandick S Batista Carlos A Lasso Donald Taphorn and Niacutedia N Fabreacute

323 Inland fisheries of tropical Africa 349Brian E Marshall

324 Fisheries of the rivers of Southeast Asia 363Robin L Welcomme Ian G Baird David Dudgeon Ashley Halls Dirk Lamberts and Md Golam Mustafa

325 Asian upland fishes and fisheries 377A Ian Payne

326 Fishes and fisheries of Asian inland lacustrine waters 384Upali S Amarasinghe and Sena S De Silva

327 Freshwater fisheries of Australasia 404Donald J Jellyman Peter C Gehrke and John H Harris

Section 4 Fishing operations

41 Introduction 421John F Craig

42 Aboriginal freshwater fisheries as resilient socialndashecological systems 422Mimi E Lam

43 Commercial inland capture fisheries 438Devin M Bartley Gertjan de Graaf and John Valbo‐Joslashrgensen

44 Recreational fisheries in inland waters 449Steven J Cooke Robert Arlinghaus Brett M Johnson and Ian G Cowx

Section 5 Fisheries management

51 Fisheries governance and management 469Robin L Welcomme

52 Assessment and modelling in freshwater fisheries 483Tony J Pitcher

53 Social benefits from inland fisheries implications for a people‐centred response to management and governance challenges 500Robert Arthur Richard Friend and Christophe Beacuteneacute

54 A human rights‐based approach to securing livelihoods depending on inland fisheries 513Nicole Franz Carlos Fuentevilla Lena Westlund and Rolf Willmann

55 The optimal fishing pattern 524Jeppe Kolding Richard Law Michael Plank and Paul A M van Zwieten

Section 6 Fisheries development

61 Introduction 543John F Craig

62 Environmental assessment for fisheries 544Nigel Milner

63 Management of freshwater fisheries addressing habitat people and fishes 557Robert Arlinghaus Kai Lorenzen Brett M Johnson Steven J Cooke and Ian G Cowx

64 Aquaculture 580Randall E Brummett and Malcolm C M Beveridge

65 Ecological implications of genetically modified fishes in freshwater fisheries with a focus on salmonids 594L Fredrik Sundstroumlm and Robert H Devlin

66 Sustainable freshwater fisheries the search for workable solutions 616Rodolphe Elie Gozlan and John Robert Britton

Section 7 The effects of perturbations on fisheries

71 Introduction 625John F Craig

72 Harvest‐induced phenotypic change in inland fisheries 626Lauren J Chapman and Diana M T Sharpe

73 Climate change and freshwater fisheries 641Chris Harrod

74 Toxicology 695Nic Bury

75 Impoundments barriers and abstractions impact on fishes and fisheries mitigation and future directions 717Paul S Kemp

76 Role and impact of non‐native species on inland fisheries the Janus syndrome 770Rodolphe Elie Gozlan

77 Eutrophication and freshwater fisheries 779Ian J Winfield

Contents ix

78 Aquaculture and the environment 794Malcolm C M Beveridge and Randall E Brummett

Section 8 Tools and future developments in freshwater fisheries

81 Introduction 807John F Craig

82 A list of suggested research areas in freshwater fisheries ecology 808John F Craig

83 Molecular ecology and stock identification 811Eleanor A S Adamson and David A Hurwood

84 Recruitment 830Thomas A Johnston Nigel P Lester and Brian J Shuter

Countries index 846

Fish index 848

Author index 860

Subject index 884

x

Eleanor A S AdamsonDepartment of Life Sciences Natural History Museum London UK

Angelo A Agostinho Nupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Upali S AmarasingheDepartment of Zoology University of Kelaniya Kelaniya Sri Lanka

Carlos AntunesCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal Aquamuseu do Rio Minho Parque do Castelinho V N Cerveira Portugal and ESG ndash Escola Superior Gallaecia Largo das Oliveiras V N Cerveira Portugal

Maacuterio Jorge ArauacutejoCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal

Robert ArlinghausDepartment of Biology and Ecology of Fishes Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Berlin Germany and Faculty of Life Sciences Humboldt‐Universitaumlt zu Berlin Berlin Germany

Robert ArthurMRAG Ltd London UK

Claudio BaiguacutenInstituto Tecnologico de Chascomus Chascomus Argentina

Ian G BairdDepartment of Geography University of Wisconsin‐Madison Madison USA

Maacuterio BarlettaLaboratoacuterio de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos Departamento de Oceanografia Universidade Federal de Pernambuco Cidade Universitaacuteria Recife Brazil

Devin M BartleyFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Vandick S BatistaUniversidade Federal de Alagoas Maceioacute Brazil

Christophe BeacuteneacuteInternational Center for Tropical Agriculture (CIAT) Cali Colombia

Malcolm C M BeveridgeWorldFish Lusaka Zambia

Pier Giorgio BiancoBiological Department Zoological Section University of Naples Naples Italy

John Robert BrittonSchool of Applied Sciences Bournemouth University Dorset UK

Randall E BrummettWorld Bank Washington USA

Mary BurridgeRoyal Ontario Museum Toronto Canada

Nic BuryFaculty of Life Sciences and Medicine Division of Diabetes and Nutritional Sciences Kingrsquos College London UK

Agostinho Carlos CatellaRecursos Pesqueiros Embrapa Pantanal Empresa Brasileira de Pesquisa Agropecuaacuteria (Embrapa Pantanal) Corumbaacute Brazil

Lauren J ChapmanDepartment of Biology McGill University Montreacuteal Canada

Louise ChavarieDepartment of Biological Sciences University of Alberta Edmonton Canada

Fernando CoboDepartamento de Zoologiacutea y Antropologiacutea Fiacutesica Universidad de Santiago de Compostela Santiago de Compostela Spain and Estacioacuten de Hidrobiologiacutea ldquoEncoro do Conrdquo Castroagudiacuten sn Pontevedra Spain

Steven J CookeFish Ecology and Conservation Physiology Laboratory Institute of Environmental Science and Department of Biology Carleton University Ottawa Canada

Paul D CowleySouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Ian G CowxHull International Fisheries Institute Department of Biological Sciences The University of Hull Kingston‐upon‐Hull UK

John F CraigCraig Consultancy Dumfries Scotland UK

List of contributors

List of contributors xi

Victor E CussacInstituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) Universidad Nacional del Comahue (UNCO) ndash Consejo Nacional de Investigaciones Cientiacuteficas y Teacutecnicas (CONICET) Bariloche Argentina

Gertjan de GraafFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Sena S De SilvaSchool of Life and Environment Sciences Deakin University Warrnambool Campus Princes Highway Warrnambool Australia

Robert H DevlinFisheries and Oceans Canada West Vancouver Canada

Yury Yu DgebuadzeSevertsov Institute of Ecology amp Evolution Moscow Russia

David DudgeonSchool of Biological Sciences The University of Hong Kong Hong Kong China

Inna ErmolaevaScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Tibor ErosBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

Niacutedia N FabreacuteUniversidade Federal de Alagoas Maceioacute Brazil

Nelson F FontouraDepartamento de Biodiversidade e Ecologia Faculdade de Biociecircncias ndash PUCRS Porto Alegre Brazil

Nicole FranzFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Richard FriendInstitute for Social amp Environmental Transition (ISET) Bangkok Thailand

Carlos FuentevillaFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Peter C GehrkeOpus International Consultants Spring Hill Australia

Daniel GerdeauxINRA Thonon les Bains France

Marie‐Pierre GosselinStricklandgate Kendal UK

Rodolphe Elie GozlanUniteacute Mixte de Recherche Biologie des Organismes et Eacutecosystegravemes Aquatiques (Institut de Recherche pour le Deacuteveloppement 207 Centre National de la Recherche Scientifique 7208 Museacuteum National drsquoHistoire Naturelle Universiteacute Pierre et Marie Curie) Museacuteum National drsquoHistoire Naturelle Paris Cedex France

Joanna GrabowskaDepartment of Ecology and Vertebrate Zoology University of Łoacutedź Łoacutedź Poland

Janina GrayThe University of Westminster London UK

Hiroshi HakoyamaNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Norm G HallCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Ashley HallsAquae Sulis (Research) Ltd (ASL) Bradford‐on‐Avon Wiltshire UK

Justin HanischDepartment of Biological Sciences University of Alberta Edmonton Canada

John H HarrisCentre for Ecosystem Science UNSW Australia

Chris HarrodInstituto de Ciencias Naturales Alexander Von Humboldt Universidad de Antofagasta Antofagasta Chile

Pavel HorkyacuteDepartment of Zoology and Fisheries Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Prague Czech Republic

David A HurwoodScience and Engineering Faculty Queensland University of Technology Brisbane Australia

Donald J JellymanNational Institute of Water and Atmosphere Christchurch New Zealand

Luz F Jimeacutenez‐SeguraInstituto de Biologiacutea Universidad de Antioquia Medelliacuten Colombia

Brett M JohnsonDepartment of Fish Wildlife and Conservation Biology Colorado State University Fort Collins USA

Thomas A JohnstonOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Cooperative Freshwater Ecology Unit Vale Living with Lakes Centre Laurentian University Sudbury Canada

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

viii Contents

320 Fisheries ecology of Greece 292Ioannis D Leonardos

321 The ecology of inland fisheries of Turkey 304Sedat V Yerli

322 Fisheries ecology in South American river basins 311Maacuterio Barletta Victor E Cussac Angelo A Agostinho Claudio Baiguacuten Edson K Okada Agostinho Carlos Catella Nelson F Fontoura Paulo S Pompeu Luz F Jimeacutenez‐Segura Vandick S Batista Carlos A Lasso Donald Taphorn and Niacutedia N Fabreacute

323 Inland fisheries of tropical Africa 349Brian E Marshall

324 Fisheries of the rivers of Southeast Asia 363Robin L Welcomme Ian G Baird David Dudgeon Ashley Halls Dirk Lamberts and Md Golam Mustafa

325 Asian upland fishes and fisheries 377A Ian Payne

326 Fishes and fisheries of Asian inland lacustrine waters 384Upali S Amarasinghe and Sena S De Silva

327 Freshwater fisheries of Australasia 404Donald J Jellyman Peter C Gehrke and John H Harris

Section 4 Fishing operations

41 Introduction 421John F Craig

42 Aboriginal freshwater fisheries as resilient socialndashecological systems 422Mimi E Lam

43 Commercial inland capture fisheries 438Devin M Bartley Gertjan de Graaf and John Valbo‐Joslashrgensen

44 Recreational fisheries in inland waters 449Steven J Cooke Robert Arlinghaus Brett M Johnson and Ian G Cowx

Section 5 Fisheries management

51 Fisheries governance and management 469Robin L Welcomme

52 Assessment and modelling in freshwater fisheries 483Tony J Pitcher

53 Social benefits from inland fisheries implications for a people‐centred response to management and governance challenges 500Robert Arthur Richard Friend and Christophe Beacuteneacute

54 A human rights‐based approach to securing livelihoods depending on inland fisheries 513Nicole Franz Carlos Fuentevilla Lena Westlund and Rolf Willmann

55 The optimal fishing pattern 524Jeppe Kolding Richard Law Michael Plank and Paul A M van Zwieten

Section 6 Fisheries development

61 Introduction 543John F Craig

62 Environmental assessment for fisheries 544Nigel Milner

63 Management of freshwater fisheries addressing habitat people and fishes 557Robert Arlinghaus Kai Lorenzen Brett M Johnson Steven J Cooke and Ian G Cowx

64 Aquaculture 580Randall E Brummett and Malcolm C M Beveridge

65 Ecological implications of genetically modified fishes in freshwater fisheries with a focus on salmonids 594L Fredrik Sundstroumlm and Robert H Devlin

66 Sustainable freshwater fisheries the search for workable solutions 616Rodolphe Elie Gozlan and John Robert Britton

Section 7 The effects of perturbations on fisheries

71 Introduction 625John F Craig

72 Harvest‐induced phenotypic change in inland fisheries 626Lauren J Chapman and Diana M T Sharpe

73 Climate change and freshwater fisheries 641Chris Harrod

74 Toxicology 695Nic Bury

75 Impoundments barriers and abstractions impact on fishes and fisheries mitigation and future directions 717Paul S Kemp

76 Role and impact of non‐native species on inland fisheries the Janus syndrome 770Rodolphe Elie Gozlan

77 Eutrophication and freshwater fisheries 779Ian J Winfield

Contents ix

78 Aquaculture and the environment 794Malcolm C M Beveridge and Randall E Brummett

Section 8 Tools and future developments in freshwater fisheries

81 Introduction 807John F Craig

82 A list of suggested research areas in freshwater fisheries ecology 808John F Craig

83 Molecular ecology and stock identification 811Eleanor A S Adamson and David A Hurwood

84 Recruitment 830Thomas A Johnston Nigel P Lester and Brian J Shuter

Countries index 846

Fish index 848

Author index 860

Subject index 884

x

Eleanor A S AdamsonDepartment of Life Sciences Natural History Museum London UK

Angelo A Agostinho Nupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Upali S AmarasingheDepartment of Zoology University of Kelaniya Kelaniya Sri Lanka

Carlos AntunesCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal Aquamuseu do Rio Minho Parque do Castelinho V N Cerveira Portugal and ESG ndash Escola Superior Gallaecia Largo das Oliveiras V N Cerveira Portugal

Maacuterio Jorge ArauacutejoCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal

Robert ArlinghausDepartment of Biology and Ecology of Fishes Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Berlin Germany and Faculty of Life Sciences Humboldt‐Universitaumlt zu Berlin Berlin Germany

Robert ArthurMRAG Ltd London UK

Claudio BaiguacutenInstituto Tecnologico de Chascomus Chascomus Argentina

Ian G BairdDepartment of Geography University of Wisconsin‐Madison Madison USA

Maacuterio BarlettaLaboratoacuterio de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos Departamento de Oceanografia Universidade Federal de Pernambuco Cidade Universitaacuteria Recife Brazil

Devin M BartleyFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Vandick S BatistaUniversidade Federal de Alagoas Maceioacute Brazil

Christophe BeacuteneacuteInternational Center for Tropical Agriculture (CIAT) Cali Colombia

Malcolm C M BeveridgeWorldFish Lusaka Zambia

Pier Giorgio BiancoBiological Department Zoological Section University of Naples Naples Italy

John Robert BrittonSchool of Applied Sciences Bournemouth University Dorset UK

Randall E BrummettWorld Bank Washington USA

Mary BurridgeRoyal Ontario Museum Toronto Canada

Nic BuryFaculty of Life Sciences and Medicine Division of Diabetes and Nutritional Sciences Kingrsquos College London UK

Agostinho Carlos CatellaRecursos Pesqueiros Embrapa Pantanal Empresa Brasileira de Pesquisa Agropecuaacuteria (Embrapa Pantanal) Corumbaacute Brazil

Lauren J ChapmanDepartment of Biology McGill University Montreacuteal Canada

Louise ChavarieDepartment of Biological Sciences University of Alberta Edmonton Canada

Fernando CoboDepartamento de Zoologiacutea y Antropologiacutea Fiacutesica Universidad de Santiago de Compostela Santiago de Compostela Spain and Estacioacuten de Hidrobiologiacutea ldquoEncoro do Conrdquo Castroagudiacuten sn Pontevedra Spain

Steven J CookeFish Ecology and Conservation Physiology Laboratory Institute of Environmental Science and Department of Biology Carleton University Ottawa Canada

Paul D CowleySouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Ian G CowxHull International Fisheries Institute Department of Biological Sciences The University of Hull Kingston‐upon‐Hull UK

John F CraigCraig Consultancy Dumfries Scotland UK

List of contributors

List of contributors xi

Victor E CussacInstituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) Universidad Nacional del Comahue (UNCO) ndash Consejo Nacional de Investigaciones Cientiacuteficas y Teacutecnicas (CONICET) Bariloche Argentina

Gertjan de GraafFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Sena S De SilvaSchool of Life and Environment Sciences Deakin University Warrnambool Campus Princes Highway Warrnambool Australia

Robert H DevlinFisheries and Oceans Canada West Vancouver Canada

Yury Yu DgebuadzeSevertsov Institute of Ecology amp Evolution Moscow Russia

David DudgeonSchool of Biological Sciences The University of Hong Kong Hong Kong China

Inna ErmolaevaScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Tibor ErosBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

Niacutedia N FabreacuteUniversidade Federal de Alagoas Maceioacute Brazil

Nelson F FontouraDepartamento de Biodiversidade e Ecologia Faculdade de Biociecircncias ndash PUCRS Porto Alegre Brazil

Nicole FranzFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Richard FriendInstitute for Social amp Environmental Transition (ISET) Bangkok Thailand

Carlos FuentevillaFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Peter C GehrkeOpus International Consultants Spring Hill Australia

Daniel GerdeauxINRA Thonon les Bains France

Marie‐Pierre GosselinStricklandgate Kendal UK

Rodolphe Elie GozlanUniteacute Mixte de Recherche Biologie des Organismes et Eacutecosystegravemes Aquatiques (Institut de Recherche pour le Deacuteveloppement 207 Centre National de la Recherche Scientifique 7208 Museacuteum National drsquoHistoire Naturelle Universiteacute Pierre et Marie Curie) Museacuteum National drsquoHistoire Naturelle Paris Cedex France

Joanna GrabowskaDepartment of Ecology and Vertebrate Zoology University of Łoacutedź Łoacutedź Poland

Janina GrayThe University of Westminster London UK

Hiroshi HakoyamaNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Norm G HallCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Ashley HallsAquae Sulis (Research) Ltd (ASL) Bradford‐on‐Avon Wiltshire UK

Justin HanischDepartment of Biological Sciences University of Alberta Edmonton Canada

John H HarrisCentre for Ecosystem Science UNSW Australia

Chris HarrodInstituto de Ciencias Naturales Alexander Von Humboldt Universidad de Antofagasta Antofagasta Chile

Pavel HorkyacuteDepartment of Zoology and Fisheries Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Prague Czech Republic

David A HurwoodScience and Engineering Faculty Queensland University of Technology Brisbane Australia

Donald J JellymanNational Institute of Water and Atmosphere Christchurch New Zealand

Luz F Jimeacutenez‐SeguraInstituto de Biologiacutea Universidad de Antioquia Medelliacuten Colombia

Brett M JohnsonDepartment of Fish Wildlife and Conservation Biology Colorado State University Fort Collins USA

Thomas A JohnstonOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Cooperative Freshwater Ecology Unit Vale Living with Lakes Centre Laurentian University Sudbury Canada

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

Contents ix

78 Aquaculture and the environment 794Malcolm C M Beveridge and Randall E Brummett

Section 8 Tools and future developments in freshwater fisheries

81 Introduction 807John F Craig

82 A list of suggested research areas in freshwater fisheries ecology 808John F Craig

83 Molecular ecology and stock identification 811Eleanor A S Adamson and David A Hurwood

84 Recruitment 830Thomas A Johnston Nigel P Lester and Brian J Shuter

Countries index 846

Fish index 848

Author index 860

Subject index 884

x

Eleanor A S AdamsonDepartment of Life Sciences Natural History Museum London UK

Angelo A Agostinho Nupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Upali S AmarasingheDepartment of Zoology University of Kelaniya Kelaniya Sri Lanka

Carlos AntunesCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal Aquamuseu do Rio Minho Parque do Castelinho V N Cerveira Portugal and ESG ndash Escola Superior Gallaecia Largo das Oliveiras V N Cerveira Portugal

Maacuterio Jorge ArauacutejoCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal

Robert ArlinghausDepartment of Biology and Ecology of Fishes Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Berlin Germany and Faculty of Life Sciences Humboldt‐Universitaumlt zu Berlin Berlin Germany

Robert ArthurMRAG Ltd London UK

Claudio BaiguacutenInstituto Tecnologico de Chascomus Chascomus Argentina

Ian G BairdDepartment of Geography University of Wisconsin‐Madison Madison USA

Maacuterio BarlettaLaboratoacuterio de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos Departamento de Oceanografia Universidade Federal de Pernambuco Cidade Universitaacuteria Recife Brazil

Devin M BartleyFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Vandick S BatistaUniversidade Federal de Alagoas Maceioacute Brazil

Christophe BeacuteneacuteInternational Center for Tropical Agriculture (CIAT) Cali Colombia

Malcolm C M BeveridgeWorldFish Lusaka Zambia

Pier Giorgio BiancoBiological Department Zoological Section University of Naples Naples Italy

John Robert BrittonSchool of Applied Sciences Bournemouth University Dorset UK

Randall E BrummettWorld Bank Washington USA

Mary BurridgeRoyal Ontario Museum Toronto Canada

Nic BuryFaculty of Life Sciences and Medicine Division of Diabetes and Nutritional Sciences Kingrsquos College London UK

Agostinho Carlos CatellaRecursos Pesqueiros Embrapa Pantanal Empresa Brasileira de Pesquisa Agropecuaacuteria (Embrapa Pantanal) Corumbaacute Brazil

Lauren J ChapmanDepartment of Biology McGill University Montreacuteal Canada

Louise ChavarieDepartment of Biological Sciences University of Alberta Edmonton Canada

Fernando CoboDepartamento de Zoologiacutea y Antropologiacutea Fiacutesica Universidad de Santiago de Compostela Santiago de Compostela Spain and Estacioacuten de Hidrobiologiacutea ldquoEncoro do Conrdquo Castroagudiacuten sn Pontevedra Spain

Steven J CookeFish Ecology and Conservation Physiology Laboratory Institute of Environmental Science and Department of Biology Carleton University Ottawa Canada

Paul D CowleySouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Ian G CowxHull International Fisheries Institute Department of Biological Sciences The University of Hull Kingston‐upon‐Hull UK

John F CraigCraig Consultancy Dumfries Scotland UK

List of contributors

List of contributors xi

Victor E CussacInstituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) Universidad Nacional del Comahue (UNCO) ndash Consejo Nacional de Investigaciones Cientiacuteficas y Teacutecnicas (CONICET) Bariloche Argentina

Gertjan de GraafFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Sena S De SilvaSchool of Life and Environment Sciences Deakin University Warrnambool Campus Princes Highway Warrnambool Australia

Robert H DevlinFisheries and Oceans Canada West Vancouver Canada

Yury Yu DgebuadzeSevertsov Institute of Ecology amp Evolution Moscow Russia

David DudgeonSchool of Biological Sciences The University of Hong Kong Hong Kong China

Inna ErmolaevaScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Tibor ErosBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

Niacutedia N FabreacuteUniversidade Federal de Alagoas Maceioacute Brazil

Nelson F FontouraDepartamento de Biodiversidade e Ecologia Faculdade de Biociecircncias ndash PUCRS Porto Alegre Brazil

Nicole FranzFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Richard FriendInstitute for Social amp Environmental Transition (ISET) Bangkok Thailand

Carlos FuentevillaFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Peter C GehrkeOpus International Consultants Spring Hill Australia

Daniel GerdeauxINRA Thonon les Bains France

Marie‐Pierre GosselinStricklandgate Kendal UK

Rodolphe Elie GozlanUniteacute Mixte de Recherche Biologie des Organismes et Eacutecosystegravemes Aquatiques (Institut de Recherche pour le Deacuteveloppement 207 Centre National de la Recherche Scientifique 7208 Museacuteum National drsquoHistoire Naturelle Universiteacute Pierre et Marie Curie) Museacuteum National drsquoHistoire Naturelle Paris Cedex France

Joanna GrabowskaDepartment of Ecology and Vertebrate Zoology University of Łoacutedź Łoacutedź Poland

Janina GrayThe University of Westminster London UK

Hiroshi HakoyamaNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Norm G HallCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Ashley HallsAquae Sulis (Research) Ltd (ASL) Bradford‐on‐Avon Wiltshire UK

Justin HanischDepartment of Biological Sciences University of Alberta Edmonton Canada

John H HarrisCentre for Ecosystem Science UNSW Australia

Chris HarrodInstituto de Ciencias Naturales Alexander Von Humboldt Universidad de Antofagasta Antofagasta Chile

Pavel HorkyacuteDepartment of Zoology and Fisheries Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Prague Czech Republic

David A HurwoodScience and Engineering Faculty Queensland University of Technology Brisbane Australia

Donald J JellymanNational Institute of Water and Atmosphere Christchurch New Zealand

Luz F Jimeacutenez‐SeguraInstituto de Biologiacutea Universidad de Antioquia Medelliacuten Colombia

Brett M JohnsonDepartment of Fish Wildlife and Conservation Biology Colorado State University Fort Collins USA

Thomas A JohnstonOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Cooperative Freshwater Ecology Unit Vale Living with Lakes Centre Laurentian University Sudbury Canada

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

x

Eleanor A S AdamsonDepartment of Life Sciences Natural History Museum London UK

Angelo A Agostinho Nupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Upali S AmarasingheDepartment of Zoology University of Kelaniya Kelaniya Sri Lanka

Carlos AntunesCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal Aquamuseu do Rio Minho Parque do Castelinho V N Cerveira Portugal and ESG ndash Escola Superior Gallaecia Largo das Oliveiras V N Cerveira Portugal

Maacuterio Jorge ArauacutejoCentro Interdisciplinar de Investigaccedilatildeo Marinha e Ambiental (CIIMARCIMAR) Universidade do Porto Porto Portugal

Robert ArlinghausDepartment of Biology and Ecology of Fishes Leibniz‐Institute of Freshwater Ecology and Inland Fisheries Berlin Germany and Faculty of Life Sciences Humboldt‐Universitaumlt zu Berlin Berlin Germany

Robert ArthurMRAG Ltd London UK

Claudio BaiguacutenInstituto Tecnologico de Chascomus Chascomus Argentina

Ian G BairdDepartment of Geography University of Wisconsin‐Madison Madison USA

Maacuterio BarlettaLaboratoacuterio de Ecologia e Gerenciamento de Ecossistemas Costeiros e Estuarinos Departamento de Oceanografia Universidade Federal de Pernambuco Cidade Universitaacuteria Recife Brazil

Devin M BartleyFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Vandick S BatistaUniversidade Federal de Alagoas Maceioacute Brazil

Christophe BeacuteneacuteInternational Center for Tropical Agriculture (CIAT) Cali Colombia

Malcolm C M BeveridgeWorldFish Lusaka Zambia

Pier Giorgio BiancoBiological Department Zoological Section University of Naples Naples Italy

John Robert BrittonSchool of Applied Sciences Bournemouth University Dorset UK

Randall E BrummettWorld Bank Washington USA

Mary BurridgeRoyal Ontario Museum Toronto Canada

Nic BuryFaculty of Life Sciences and Medicine Division of Diabetes and Nutritional Sciences Kingrsquos College London UK

Agostinho Carlos CatellaRecursos Pesqueiros Embrapa Pantanal Empresa Brasileira de Pesquisa Agropecuaacuteria (Embrapa Pantanal) Corumbaacute Brazil

Lauren J ChapmanDepartment of Biology McGill University Montreacuteal Canada

Louise ChavarieDepartment of Biological Sciences University of Alberta Edmonton Canada

Fernando CoboDepartamento de Zoologiacutea y Antropologiacutea Fiacutesica Universidad de Santiago de Compostela Santiago de Compostela Spain and Estacioacuten de Hidrobiologiacutea ldquoEncoro do Conrdquo Castroagudiacuten sn Pontevedra Spain

Steven J CookeFish Ecology and Conservation Physiology Laboratory Institute of Environmental Science and Department of Biology Carleton University Ottawa Canada

Paul D CowleySouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Ian G CowxHull International Fisheries Institute Department of Biological Sciences The University of Hull Kingston‐upon‐Hull UK

John F CraigCraig Consultancy Dumfries Scotland UK

List of contributors

List of contributors xi

Victor E CussacInstituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) Universidad Nacional del Comahue (UNCO) ndash Consejo Nacional de Investigaciones Cientiacuteficas y Teacutecnicas (CONICET) Bariloche Argentina

Gertjan de GraafFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Sena S De SilvaSchool of Life and Environment Sciences Deakin University Warrnambool Campus Princes Highway Warrnambool Australia

Robert H DevlinFisheries and Oceans Canada West Vancouver Canada

Yury Yu DgebuadzeSevertsov Institute of Ecology amp Evolution Moscow Russia

David DudgeonSchool of Biological Sciences The University of Hong Kong Hong Kong China

Inna ErmolaevaScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Tibor ErosBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

Niacutedia N FabreacuteUniversidade Federal de Alagoas Maceioacute Brazil

Nelson F FontouraDepartamento de Biodiversidade e Ecologia Faculdade de Biociecircncias ndash PUCRS Porto Alegre Brazil

Nicole FranzFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Richard FriendInstitute for Social amp Environmental Transition (ISET) Bangkok Thailand

Carlos FuentevillaFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Peter C GehrkeOpus International Consultants Spring Hill Australia

Daniel GerdeauxINRA Thonon les Bains France

Marie‐Pierre GosselinStricklandgate Kendal UK

Rodolphe Elie GozlanUniteacute Mixte de Recherche Biologie des Organismes et Eacutecosystegravemes Aquatiques (Institut de Recherche pour le Deacuteveloppement 207 Centre National de la Recherche Scientifique 7208 Museacuteum National drsquoHistoire Naturelle Universiteacute Pierre et Marie Curie) Museacuteum National drsquoHistoire Naturelle Paris Cedex France

Joanna GrabowskaDepartment of Ecology and Vertebrate Zoology University of Łoacutedź Łoacutedź Poland

Janina GrayThe University of Westminster London UK

Hiroshi HakoyamaNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Norm G HallCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Ashley HallsAquae Sulis (Research) Ltd (ASL) Bradford‐on‐Avon Wiltshire UK

Justin HanischDepartment of Biological Sciences University of Alberta Edmonton Canada

John H HarrisCentre for Ecosystem Science UNSW Australia

Chris HarrodInstituto de Ciencias Naturales Alexander Von Humboldt Universidad de Antofagasta Antofagasta Chile

Pavel HorkyacuteDepartment of Zoology and Fisheries Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Prague Czech Republic

David A HurwoodScience and Engineering Faculty Queensland University of Technology Brisbane Australia

Donald J JellymanNational Institute of Water and Atmosphere Christchurch New Zealand

Luz F Jimeacutenez‐SeguraInstituto de Biologiacutea Universidad de Antioquia Medelliacuten Colombia

Brett M JohnsonDepartment of Fish Wildlife and Conservation Biology Colorado State University Fort Collins USA

Thomas A JohnstonOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Cooperative Freshwater Ecology Unit Vale Living with Lakes Centre Laurentian University Sudbury Canada

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

List of contributors xi

Victor E CussacInstituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA) Universidad Nacional del Comahue (UNCO) ndash Consejo Nacional de Investigaciones Cientiacuteficas y Teacutecnicas (CONICET) Bariloche Argentina

Gertjan de GraafFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Sena S De SilvaSchool of Life and Environment Sciences Deakin University Warrnambool Campus Princes Highway Warrnambool Australia

Robert H DevlinFisheries and Oceans Canada West Vancouver Canada

Yury Yu DgebuadzeSevertsov Institute of Ecology amp Evolution Moscow Russia

David DudgeonSchool of Biological Sciences The University of Hong Kong Hong Kong China

Inna ErmolaevaScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Tibor ErosBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

Niacutedia N FabreacuteUniversidade Federal de Alagoas Maceioacute Brazil

Nelson F FontouraDepartamento de Biodiversidade e Ecologia Faculdade de Biociecircncias ndash PUCRS Porto Alegre Brazil

Nicole FranzFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Richard FriendInstitute for Social amp Environmental Transition (ISET) Bangkok Thailand

Carlos FuentevillaFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Peter C GehrkeOpus International Consultants Spring Hill Australia

Daniel GerdeauxINRA Thonon les Bains France

Marie‐Pierre GosselinStricklandgate Kendal UK

Rodolphe Elie GozlanUniteacute Mixte de Recherche Biologie des Organismes et Eacutecosystegravemes Aquatiques (Institut de Recherche pour le Deacuteveloppement 207 Centre National de la Recherche Scientifique 7208 Museacuteum National drsquoHistoire Naturelle Universiteacute Pierre et Marie Curie) Museacuteum National drsquoHistoire Naturelle Paris Cedex France

Joanna GrabowskaDepartment of Ecology and Vertebrate Zoology University of Łoacutedź Łoacutedź Poland

Janina GrayThe University of Westminster London UK

Hiroshi HakoyamaNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Norm G HallCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Ashley HallsAquae Sulis (Research) Ltd (ASL) Bradford‐on‐Avon Wiltshire UK

Justin HanischDepartment of Biological Sciences University of Alberta Edmonton Canada

John H HarrisCentre for Ecosystem Science UNSW Australia

Chris HarrodInstituto de Ciencias Naturales Alexander Von Humboldt Universidad de Antofagasta Antofagasta Chile

Pavel HorkyacuteDepartment of Zoology and Fisheries Faculty of Agrobiology Food and Natural Resources Czech University of Life Sciences Prague Prague Czech Republic

David A HurwoodScience and Engineering Faculty Queensland University of Technology Brisbane Australia

Donald J JellymanNational Institute of Water and Atmosphere Christchurch New Zealand

Luz F Jimeacutenez‐SeguraInstituto de Biologiacutea Universidad de Antioquia Medelliacuten Colombia

Brett M JohnsonDepartment of Fish Wildlife and Conservation Biology Colorado State University Fort Collins USA

Thomas A JohnstonOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Cooperative Freshwater Ecology Unit Vale Living with Lakes Centre Laurentian University Sudbury Canada

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

xii List of contributors

Bror JonssonNorwegian Institute for Nature Research Oslo Norway

Nina JonssonNorwegian Institute for Nature Research Oslo Norway

Zbigniew KaczkowskiDepartment of Applied Ecology University of Łoacutedź Łoacutedź Poland

Osamu KatanoNational Research Institute of Aquaculture Fisheries Research Agency Ueda Japan

Paul S KempInternational Centre for Ecohydraulics Research Faculty of Engineering and the Environment University of Southampton Southampton UK

Valerio KetmaierUnit of Evolutionary BiologySystematic Zoology Institute of Biochemistry and Biology University of Potsdam Potsdam Germany and Department of Biology and Biotechnology ldquoCharles Darwinrdquo University of Rome ldquoSapienzardquo Rome Italy

Jeppe KoldingDepartment of Biology University of Bergen Bergen Norway

Vladimiacuter Kovaacutec Faculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Carlos A LassoInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Mimi E LamPolicy and Ecosystem Restoration in Fisheries Fisheries Centre and Department of Earth Ocean and Atmospheric Sciences University of British Columbia Vancouver Canada

Dirk LambertsLaboratory of Aquatic Ecology Evolution and Conservation University of Leuven Leuven Belgium

Carlos A LassoInstituto de Investigacioacuten de los Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

Thomas E LauerAquatic Biology and Fisheries Center Ball State University Muncie USA

Richard LawYork Centre for Complex Systems Analysis Ron Cooke Hub University of York York UK

Ioannis D LeonardosBiological Applications and Technology Department University of Ioannina Ioannina Greece

Nigel P LesterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section DNA Building Trent University Peterborough Canada

Kai LorenzenFisheries and Aquatic Sciences School of Forest Resources and Conservation University of Florida Gainesville USA

Nicholas MandrakDepartment of Biological Sciences University of Toronto Scarborough Toronto Canada

Brian E MarshallDepartment of Biological Sciences University of Zimbabwe Harare Zimbabwe and Lake Victoria Fisheries Organisation Jinja Uganda

Shin‐ichiro S MatsuzakiCenter for Environmental Biology and Ecosystem National Institute for Environmental Studies Tsukuba Japan

Nigel MilnerAPEM Ltd School of Biological Sciences Bangor University Gwynedd UK

Rafael MirandaDepartment of Environmental Biology University of Navarra Navarra Spain

Brian MossSchool of Environmental Sciences University of Liverpool Liverpool UK

Md Golam MustafaWorldFish Dhaka Bangladesh

Andrea NovomeskaacuteFaculty of Natural Sciences Department of Ecology Comenius University Mlynskaacute dolina Bratislava Slovakia

Edson K OkadaNupelia Universidade Estadual de Maringaacute Maringaacute Brazil

Cynthia PaszkowskiDepartment of Biological Sciences University of Alberta Edmonton Canada

A Ian PayneMRAG Ltd London UK

Geoff PettsThe University of Westminster London UK

Tony J PitcherFisheries Centre Policy and Ecosystem Restoration in Fisheries University of British Columbia Vancouver Canada

Michael PlankDepartment of Mathematics and Statistics University of Canterbury Christchurch New Zealand

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

List of contributors xiii

Paulo S PompeuDepartamento de Biologia Universidade Federal de Lavras Lavras Brazil

John R PostBiological Sciences University of Calgary Calgary Canada

Ian C PotterCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

Mark PyronAquatic Biology and Fisheries Center Ball State University Muncie USA

Victor RizevskiScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Vitaliy SemenchenkoScientific and Practical Centre for Bioresources National Academy of Sciences Minsk Republic of Belarus

Diana M T SharpeDepartment of Biology McGill University Montreacuteal Canada and Unidad de Ecologiacutea y Biodiversidad Instituto de Investigaciones Cientiacuteficas y Servicios de Alta Tecnologiacutea (INDICASAT‐AIP) Panamaacute Repuacuteblica de Panamaacute

Brian J ShuterOntario Ministry of Natural Resources Aquatic Research and Monitoring Section Department of Ecology and Evolutionary Biology University of Toronto Toronto Canada

Andraacutes SpecziaacuterBalaton Limnological Institute MTA Centre for Ecological Research Tihany Hungary

L Fredrik SundstroumlmDepartment of Ecology and GeneticsAnimal Ecology Evolutionary Biology Centre Uppsala University Uppsala Sweden

Heidi SwansonDepartment of Biological Sciences University of Alberta Edmonton Canada and Department of Biology University of Waterloo Waterloo Canada

Donald TaphornInstituto de Investigacioacuten de Recursos Bioloacutegicos Alexander von Humbolt Bogotaacute Colombia

William TonnDepartment of Biological Sciences University of Alberta Edmonton Canada

James R TweedleyCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia

John Valbo‐JoslashrgensenFood and Agriculture Organization of the United Nations Subregional Office for Central America Panama Panama

Paul A M van ZwietenAquaculture and Fisheries Group Wageningen University Wageningen The Netherlands

Richard M WarwickCentre for Fish and Fisheries Research School of Veterinary amp Life Sciences Murdoch University Murdoch Australia and Plymouth Marine Laboratory Plymouth UK

Robin L WelcommeDepartment of Ecology and Evolution Imperial College Conservation Science Berkshire UK

Lena WestlundFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Olaf L F WeylSouth African Institute for Aquatic Biodiversity Grahamstown South Africa

Rolf WillmannFisheries and Aquaculture Department Food and Agriculture Organization of the United Nations Rome Italy

Ian J WinfieldLake Ecosystems Group Centre for Ecology amp Hydrology Lancaster Environment Centre Lancaster UK

Sedat V YerliDepartment of Biology Hacettepe University Ankara Turkey

Chunguang ZhangNational Zoological Museum Institute of Zoology Chinese Academy of Sciences Beijing China

Yahui ZhaoKey Laboratory of Zoological Systematics and Evolution Institute of Zoology Chinese Academy of Sciences Beijing China

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

xiv

FSBI (The Fisheries Society of the British Isles) has always had an interest beyond fisheries and indeed beyond the British Isles and so I am delighted to see the publication of this landmark book on the ecology of the worldrsquos freshwater fisheries The public perception and lionrsquos share of the fisheries worldrsquos research resources are understandably dominated by its larger and louder marine component but in almost every country there exists a diverse range of freshwater fisheries of great envi-ronmental and socio-economic importance Although these operations may vary in size from large enterprises down to miniscule operations involving just a few individuals operating over very small areas they still need and deserve scientific understanding and careful sustainable management just as much as do their typically larger marine counterparts Moreover the ecosystems-based approach increasingly followed at sea is arguably even more important in smaller inland waters In such enclosed areas fisheries operations can have direct and indirect effects which may rapidly transmit down up and beyond the

food chain with demonstrable consequences at the ecosystem level This remarkably extensive and diverse book taking an ecological approach which covers the environment in as much detail as the fish provides a major contribution to helping scien-tists managers and fishers meet the challenges currently facing freshwater fisheries around the globe

At a time when various factors conspire to divert the efforts of many of the worldrsquos researchers away from writing book chap-ters it is to John Craigrsquos immense credit that he has been able to assemble and successfully shepherd over one hundred of the worldrsquos leading experts on freshwater ecosystems resources fisheries operations and fisheries management to produce the present timely and authoritative volume I have no doubt that this remarkable volume will inform fish and fisheries students and researchers alike and inspire their future colleagues for many years to come

Ian J WinfieldPresident FSBI

Foreword

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

xv

The study of freshwater fisheries ecology Does this bring together the fish biologist the fisher and the manager For a long period of time these disciplines hardly met and I can remember in the early 1980s a fishery manager stating that he relied only on economic and social aspects to manage his inland fisheries indi-cating that if these aspects were cared for the biology would look after itself As fishery yields and species diversity decline and competition for limited water resources and negative perturba-tions to the ecosystem increase it is apparent that this belief has not worked (as was clear to me at the time) and the need for sound scientific data to advise not only on the fisheries but also manage the water resources has become vital

I have always considered myself to be a fish biologist in particular an ecologist but many aspects of my studies and their application have been related to the fishery in the systems where I have worked ranging from boreal forests to the tropics I started at Slapton Ley Devon (where there was a recreational fishery for perch Perca fluviatilis pike Esox lucius and cyprin-ids) and then moved to Windermere (where a wartime fishery for P fluviatilis and an experimental fishery for E lucius had started some of the longest continuous studies of animal popu-lations anywhere in the world) I worked next in Manitoba Canada At that time (in the 1980s) there were commercial and recreational fisheries eg in winter under the ice for walleye Sander vitreus and then I moved to warmer climes These included Nepalese rivers and reservoirs the beels of Assam India African rift valley lakes (in particular Lake Tanganyika where the fishery is dependent on only three pelagic species the clupeids Stolothrissa tanganicae and Limnothrissa miodon and the centropomid Lates stappersii) and finally Lake Nasser in Egypt where stocking of hatchery‐reared Nile tilapia

Oreochromis niloticus was taking place These young fish had no protection from predators as there was no motherrsquos mouth in which to hide It might have been better to introduce a fish to fill the pelagic void eg L miodon from Lake Tanganyika as has been carried out in Lake Kariba In addition I have gained many insights to fish biology through editing an international journal carrying out consultancy work on large dams and advising research institutes in developing countries These experiences instilled in me a latent desire to link ecology and fishery science on a global scale and I have been very fortunate in gathering together a large team of colleagues to undertake this task These authors are a talented group of scientists and together they have been able to cover nearly all aspects of freshwater fisheries ecology

A large number of the contributions outline many negative changes that have occurred to our freshwater resources although some have been positive in their final analysis eg lsquoAfrican fish-eries have proved to be very resilient and should if effectively managed meet the future needs of the populationrsquo It is very apparent that we need to sit up and take note of what is happen-ing to our freshwater fisheries and use the tools available to mitigate against severe perturbations We need to invest in research in particular the collection of long‐term data sets We need to equip ourselves with the methods to assess freshwater resources to share these with other users and to conserve what we have for the benefit of the planet We need new approaches to management including some from the fishers themselves many of whom are indigenous people Hopefully the contributions in this book will provide the foundations for the way ahead

John F Craig

Preface

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

xvi

Acknowledgements

Firstly I would like to thank all 112 authors some of whom have contributed to more than one chapter I apologize to them for the long‐drawn‐out period of putting this book together and thank them for their patience Secondly I would like to acknowl-edge all those people many deceased who have enthused and inspired me in my love of biology over my career including among many others Bob White Johnny Watson John Carthy Brian Petts Winifred Frost Charlotte Kipling Tim Bagenal David Le Cren Ray Beverton John Thorpe Ro Lowe-McConnell

John Babaluk Drew Bodaly Fred Ward Bo Bengtsson and Piero Mannini Thirdly I appreciate all the efforts of those involved in the production of this book at Wiley in particular Radjan LourdeSelvanadin and my colleague of long standing Nigel Balmforth Thanks to Nick Kemp for providing the impe-tus to finally get going on this project My main support has been my wife Hilary who although trained as a historian and musician has applied herself to the lsquoalienrsquo field of fish biology and fisheries

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

Freshwater fisheries ecology

Section 1

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

3

A fishery may be considered as a system composed of three interacting components the aquatic biota the aquatic habitat and the human users of these renewable natural resources it is part of a complex and unpredictable ecosystem (Nielsen amp Lackey 1980) Although fisheries in general are considered from biological economic and social aspects the emphasis in this book is on an ecosystem approach The pre‐eminence throughout has been on the science of freshwater fisheries Levin (1992) pointed out Understanding patterns in terms of the processes that produce them is the essence of science

We should remind ourselves of the definitions of the words ecology and ecosystem It is worth quoting Odum (1963) since his definitions are still appropriate today lsquoecology a word derived from the Greek root ldquooikosrdquo meaning ldquohouserdquo Thus liter-ally ecology is the study of ldquohousesrdquo or more broadly ldquoenviron-mentsrdquo Because ecology is concerned especially with the biology of groups of organisms and with functional processes on the lands in the oceans and in fresh waters it is more in keeping with the modern emphasis to define ecology as the study of the structure and function of nature It should be thoroughly understood that mankind is a part of nature since we are using the word nature to include the living worldrsquo Following on from this definition lsquoThe community and the nonliving environment function together as an ecological system or ecosystemrsquo Ecosystems can vary in size but each is a functional unit dependent on the interaction

between living organisms and their non-living environment If a part of an ecosystem is damaged or eliminated it affects other parts of the ecosystem A healthy ecosystem is one which is sustainable balanced and usually diverse

The diversity and diffuse nature of freshwater fisheries and their effects on inland ecosystems have made it very hard to collect adequate data making management difficult Many marine fisheries have been able to attract government support and political influence because they tend to be relatively large operations controlled by relatively few people whereas inland fisheries are in the hands of many small operators who are usu-ally politically powerless although this may not be the case for recreational fisheries of developed countries

One of the most significant differences between marine and inland fisheries is competition for water Whereas marine fisheries face no competition major development projects such as dams industries and agriculture (the last is responsible for c 70 of freshwater withdrawals) are consuming increasing quantities of fresh water and influencing its availability The supply of fresh water is limited (demand will often be greater than supply) and with increasing pressure on this resource it is likely that fisheries will have the lowest priority Fresh water makes up c 25 of the volume of water in our biosphere of which 687 is locked up in glaciers and permanent snow 301 is found at depth underground and 09 is ground frost

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

Chapter 11

Abstract This introductory chapter defines the freshwater ecosystem and fisheries including the species utilised and makes comparisons with the marine system It also outlines the scope of the book

Keywords aims ecology ecosystem fishes food resources fresh water fisheries species sustainable

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

4 Freshwater fisheries ecology

and permafrost leaving lt03 as liquid surface water (00075 of all water fresh and salt) (Mittermeier et al 2011) Of the total surface fresh water most (98) is found in lakes swamps and wetlands and thus only a very small amount is found flowing in rivers and streams

Fresh waters contain many different habitats and support about a third of all vertebrate species (c 19 000 in total) (Baillie et al 2004) in addition to numerous species of plants and invertebrates Although there are c 13 000 freshwater fish species or c 15 000 species inhabiting fresh water and brackish water (Leveque et al 2008) it is interesting that only a few species (either endemic or introduced) make a major contribu-tion to those harvested for manrsquos consumption These include rainbow trout Oncorhynchus mykiss brown trout Salmo trutta Atlantic salmon Salmo salar Pacific salmon Oncorhynchus spp Arctic charr Salvelinus alpinus whitefishes Coregonus spp eels Anguilla spp common carp Cyprinus carpio tilapia Oreochromis niloticus and Oreochromis mossambicus lsquokapentarsquo Limnothrissa miodon and Stolothrissa tanganicae Chinese carps Ctenopharyngodon idella Hypophthalmichthys molitrix Hypophthalmichthys nobilis and Mylopharyngodon piceus river catfishes Pangasius spp and Clarias gariepinus and mullets Mugil spp Many other species are caught locally for food or for recreational fishing

Inland fisheries are vital in the livelihoods and food resources of humans worldwide both economically and recreationally but their importance is clearly underestimated This is perhaps because large numbers of small operators are involved (even small boys fishing in their spare time) and most of the catch is consumed directly or sold locally and never makes its way into official statistics

The aim of this book is to globally describe what we have what we are going to lose and why and what we can save and mitigate for given the right tools First the dynamics of fresh-water ecosystems (rivers lakes and estuaries) and what drives the fisheries are given providing the background to fish pro-duction Then freshwater fisheries resources worldwide (from boreal to tropical regions) and how these are utilized and abused are outlined Details of different types of fisheries artisanal commercial and recreational are given in relation to current practices The next section deals with fisheries governance and management including assessment methods The chapters on fisheries development concentrate on improving fisheries

through environmental and habitat assessment enhancement and rehabilitation aquaculture genetically modified fishes and sustainability The impacts of and on fisheries caused by har-vesting climate change toxicology impoundments barriers and abstractions non‐native species eutrophication and aqua-culture are then described Finally articles are provided on tools and developments in freshwater fisheries including key areas of future research molecular ecology and stock identification and estimating recruitment

Fishes (the plural for more than one species) in this book are confined to the finned variety (aquatic vertebrates that have gills throughout life and limbs if any in the shape of fins Nelson 2006) as to extend further (eg include invertebrates) would go beyond the limits of an already very large tome Estuaries have been included as far as their dynamics and resources as they form a link between freshwater and marine ecosystems and sev-eral fish species which are important in freshwater fisheries pass through them eg catadromous anguillids and anadromous salmonids

references

Baillie J E M Hilton‐Taylor C amp Stuart S N (2004) 2004 IUCN Red List of Threatened Species A Global Species Assessment Gland and Cambridge IUCN

Leveque C Oberdorff T Paugy D Stiassny M L J amp Tesesco P A (2008) Global diversity of fish (Pisces) in freshwater Hydrobiologia 595 545ndash567

Levin S A (1992) The problem of pattern and scale in ecology Ecology 73 1943ndash1967

Mittermeier R A Brooks T M Farrell T A Upgren A J Harrison I J Contreras‐MacBeath Sneider R Oberfeld F Rosenberg A A Boltz F Gascon C amp Langrand O (2011) Introduction In Fresh Water The Essence of Life (Mittermeier R A Farrell T A Harrison I J Upgren A J amp Brooks T M eds) pp 15ndash17 New York NY CEMEX

Nelson J S (2006) Fishes of the World 4th edn Hoboken NJ John Wiley amp Sons Inc

Nielsen L A amp Lackey R T (1980) Introduction In Fisheries Management (Lackey R T amp Nielsen L A eds) pp 3ndash14 Oxford Blackwell Scientific Publications

Odum E P (1963) Ecology New York NY Holt Rinehart and Winston Inc

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

Freshwater ecosystems

Section 2

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

7

The study of freshwater or saline water contained within continental boundaries is defined as limnology A quick Google search will provide a list of suitable current texts on the subject Limnology together with oceanography includes all aquatic ecosystems The science of limnology (physics chemistry and biology) encompasses running or lotic and standing or lentic waters including streams rivers lakes and estuaries and also micro-habitats Long‐term data have been collected in many of these systems as well as in experimental lakes and enclosures

Lakes have probably received most attention as they have many features in common which can be extrapolated from one system to another and predictive models can be built In contrast although historically the community structure along the gradient of a river has been used to classify different zones which are inhabited by fishes with similar habitat requirements (Huet 1959 Hawkes 1975) these classifications have been too site specific and cannot be generalized Recent attempts at establishing functional ecological guilds of fish communities in European riv-ers have highlighted gaps in knowledge and the problems of extrapolating from for example northern to southern European rivers (Noble et al 2007) Estuaries are probably similar Although the need to have a reliable definition of estuaries has been recog-nized for a long period of time (Elliott amp McLusky 2002 Potter et al 2010) the wide variation in the physico‐chemical charac-teristics of estuarine ecosystems has meant that this is not an easy task Recently a guild approach has been applied to estuarine fishes (Elliott et al 2007 Potter et al 2013)

Chapters 22 to 24 describe the physical and chemical dynam-ics of rivers lakes and estuaries and the communities or guilds of fishes they support The study of limnology has many applications including predicting the impact of dam and barrier construction

pollution eutrophication and fish production and these are highlighted All contributions indicate the damage done to these systems by humans the uncertainties ahead for example climate change and the methods of rehabilitation (although the original states will never be recovered) given political will and investment

References

Elliott M amp McLusky D S (2002) The need for definitions in under-standing estuaries Estuarine Coastal and Shelf Science 55 815ndash827

Elliott M Whitfield A K Potter I C Blaber S J M Cyrus D P Nordlie F G amp Harrison T D (2007) The guild approach to catego-rizing estuarine fish assemblages A global review Fish and Fisheries 8 241ndash268

Hawkes H A (1975) River zonation and classification In River Ecology (Whitton B A ed) pp 312ndash374 Oxford Blackwell Scientific Publications

Huet M (1959) Profiles and biology of Western European streams as related to fish management Transactions of the American Fisheries Society 88 155ndash163

Noble R A A Cowx I G Goffaux D amp Kestemont P (2007) Assessing the health of European rivers using functional ecological guilds of fish communities Standardising species classification and approach to metric selection Fisheries Management and Ecology 14 381ndash392

Potter I C Chuwen B M Hoeksema S D amp Elliott M (2010) The concept of an estuary A definition that incorporates systems which can become closed to the ocean and hypersaline Estuarine Coastal and Shelf Science 87 497ndash500

Potter I C Tweedley J R Elliott M amp Whitfield A K (2013) The ways in which fish use estuaries A refinement and expansion of the guild approach Fish and Fisheries DOI 101111faf12050

Introduction

John F CraigCraig Consultancy Dumfries Scotland UK

ChapteR 21

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

Freshwater Fisheries Ecology First Edition Edited by John F Craig copy 2016 John Wiley amp Sons Ltd Published 2016 by John Wiley amp Sons Ltd

9

Introduction

River networks are a fundamental feature of the earthrsquos surface draining nearly 70 of the continents Their com-bined annual flow is equivalent to run‐off of 3945 cm from the entire land surface from which they also transport an esti-mated 10ndash20 Gt yearminus1 of sediment to the oceans (Voumlroumlsmarty et al 2003) Approximately half of the fresh water renewed each year c 20 000 km3 yearminus1 runs rapidly to the sea in floods (Shen et al 2008) Worldwide between 1992 and 2001 floods caused 39 of the disasters and they were responsible for 40 of the total economic losses and 18 of the deaths Droughts were responsible for 10 of the disasters but caused 52 of the deaths (IFRC 2002) The value of the ecosystem services provided by large floodplain rivers is considerable however and estimated at 200 times that of cropland (Constanza et al 1997) Throughout history river fisheries have been an important component of these ecosystem ser-vices Given the hazards presented by rivers and the services they provide it is not surprising that the development of riv-ers and their floodplains has had such a prominent role in the history of human civilizations The fear of disaster inspired innovations in flood control land drainage and water supply development but often with negative impacts upon riverine fish populations and fisheries (Petts 1984)

Physical processes impose fundamental and complex controls on aquatic and riparian ecosystems Hydrological processes directly impact the life cycles of riverine organisms and have indi-rect effects as river channel forms and their dynamics determine the mosaic of habitat patches available to biota In his classic work Welcomme (1979) differentiated two fundamental types of river from a fisheries perspective First lsquoflood riversrsquo experience large seasonal variations of flow often inundating extensive areas of floodplain which undergo marked seasonal flooding and dry-ing Secondly lsquoreservoir riversrsquo have a more stable flow through-out the year due to the presence of major lakes or wetlands The second has diversified fish communities with trophic specializa-tion and well‐defined food webs that differ widely from the com-munities of flood rivers behaviourally and dynamically The fauna of flood rivers has evolved and become adapted to the flood regime and shows a diverse and abundant fish fauna which sup-ports lsquosome of the richest of inland fisheriesrsquo (Welcomme 1979) This binary view of river types however masks a considerable variety determined by regional climatic differences longitudinal patterns within drainage basins and more local variations reflect-ing the history of each drainage basin and its river network over recent and geological timescales

Rivers provide routeways for fishes to migrate from sea to source and during seasonal floods from main river channels into floodplains and wetlands Many species have evolved upstream

The dynamics of rivers in relation to fishes and fisheries

Geoff Petts1 Marie‐Pierre Gosselin2 and Janina Gray1

1 The University of Westminster London UK2 Stricklandgate Kendal UK

ChapTer 22

Abstract Rivers are fundamental features of landscapes slowly etching the drainage networks and their catchments over millennia Within such evolutionary timescales fishes have adapted to the physical dynamics of river systems that is to the changing pattern of flows and the spatial patterns of habitat availability created by the flow variations This chapter explores the physical dynamics of three-dimensional river systems from the perspective of fishes It introduces the fundamental bases for understanding catchment-scale patterns of flow and sediment transport variations their effects on channel styles at the sector scale and the patterns of hydraulic habitats for fishes at the reach scale Finally we briefly examine human modifications to river systems and their flows and physical habitats and introduce the need for river management in a context of uncertain climatic futures

Keywords rivers flow regime sediments channel morphology river fish human impacts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

10 Freshwater ecosystems

downstream and lateral migratory behaviours to access habitats throughout the drainage network Moreover flowing water along rivers has a number of advantages for biota over still waters Not only does it drive the passive downstream dispersal of organisms and matter from mountain headwater streams to the sea but also because it is constantly mixed by turbulence running water provides nutrients exchange of respiratory gases and removal of wastes from the channel bed Upstream through the stream network with increasing altitude declining temperature and shallower and narrower channels with coarser bed sediments there is a progressive succession of fish population characteris-tics Typically upstream there is a gradual decrease in the num-ber of fish species with a reduction in species richness (Bacalbasa‐Dobrovici 1989) Within very large catchments non‐linear relationships reflect natural biogeographical divides and today human impacts such as dams channelization and pollution Thus for the Mississippi Fremling et al (1989) reported a progressive decrease from delta (114 species) to source (49 species) with irregularities through the middle course In this chapter we explore the natural dynamics of rivers to pro-vide a template for understanding the diversity and productivity of riverine fish populations throughout drainage networks

The nature of river networks

River networks have evolved over geological timescales to con-vey water from rainfall and in some areas snowmelt and ice melt from the mountains to the oceans The work done by rivers is also responsible for sculpting the landscape by transporting in particulate or solute form the products of rock weathering and erosion Rivers are physical systems with a history The river valleys that make up their drainage basins contain evidence of long‐term climatic change and changing patterns of basin denudation In high latitudes and midlatitudes this evidence spans the time during and since the last glaciations During the Pleistocene most of the temperate zone was polar or sub‐polar with land ice reaching latitude 45deg and sea levels were much lower than today At other times during this period monsoonal‐type rains extended at least 1000 km further polewards Beyond the glacial limit evidence of changes within fluvial systems extends to even longer timescales in some cases of more than a million years Under contemporary climate regimes the physical character and dynamics of each river system reflect the interaction of hydrological processes and terrestrial vegetation dynamics superimposed upon a valley structure width slope and any sedi-mentary fill inherited from previous climatic regimes

The structure of river systems

The fundamental hydrological characteristics of river systems reflect the global subparallel climatic regimes that are dupli-cated in the two hemispheres The distribution of the land

masses predominantly in the northern hemisphere disrupts this pattern creating a continental east‐coast effect in temper-ate latitudes and an arid west‐coast effect in the tropics Schemes for the classification of river systems such as pro-posed by Lotspeich (1980) use climate and geology as primary controls soil and vegetation are secondary factors (eg Table 221) Within each drainage network the physical vari-ables describing a river system change from headwaters to mouth and the character and dynamics of rivers are strongly scale dependent lsquoRiversrsquo range from small ephemeral headwa-ter rills and streams to large waterways often crossing national frontiers Large rivers may be conceptualized as three zones (Schumm 1977) Headwater zone 1 has strong links to the ter-restrial system both as the primary sediment producer and through the marked influence of riparian vegetation on nar-row streams Shading reduces autotrophic production and the riparian zone contributes large quantities of allochthonous detritus and woody debris The substratum is composed of coarse gravels boulders and bedrock and water temperature shows a low seasonal range and weak diurnal variation Zone 2 is dominated by longitudinal transfers of water sediment and organic matter from upstream (Fig 221) The variable dis-charge coarse substratum mobile channels broad seasonal and wide diel temperature ranges and rising importance of autochthonous primary production favour a diverse fauna Channel dynamics in this zone are strongly influenced by

Table 221 Summary of river characteristics within the major climatic zones

Climatic region Characteristics of rivers

High latitudes The extensive forest cover on permafrost gives braided rivers a distinctive dark colour and low pH with low dissolved solids during the summer thaw when the channel bed and banks can be subjected to extreme scouring by the spring ice run

Temperate montane glacier‐ and snow‐fed rivers

Strong seasonal and diurnal flow cycles reflect rates of ice melt and snowmelt typically with high sediment loads especially at the start of the melt season

Temperate midlatitudes

About 55ndash30deg North and South rivers are dominated by the effects of vegetation cover so that sediment loads are low and seasonal flow patterns relate to precipitation in winter and evapotranspiration in summer

Mediterranean Extreme seasonal flow variations feature a marked dry season with highest sediment loads during the first rains of winter following soil desiccation

Tropical and equatorial latitudes

About 30deg North and 20deg South represents the largest fraction of the earthrsquos total area This has experienced relatively stable conditions for a long period of time so that the lsquotruersquo equatorial river is characterized by low relief and almost no solids or dissolved loads because of the massive plant cover and deeply leached soils Monsoonal rainfall can generate high prolonged floods and high sediment loads can be found on mountain rivers within this zone

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

The dynamics of rivers in relation to fishes and fisheries 11

woody vegetation along the channel margins Zone 3 is the depositional zone The alluvial valley or delta is dominated by a relatively stable flow regime fine sediments and a large num-ber of degree days with primary production being limited by water depth and high turbidity The morphological complexity of the channel margins with important snag habitats (Fig 222) is central to sustaining habitat diversity and pro-ductivity The changing downstream character of large rivers is reflected by the classic fish zonation Thus in Western Europe Hawkes (1975) showed that zone 1 is characterized by

brown trout Salmo trutta and passes downstream into zone 2 with minnow Phoxinus phoxinus chub Leuciscus cephalus gudgeon Gobio gobio grayling Thymallus thymallus and barbel Barbus barbus Then in zone 3 the fish fauna includes bream Abramis brama roach Rutilus rutilus dace Leuciscus leuciscus pike Esox lucius and perch Perca fluviatilis

Differences in the magnitudes and rates of ecological pro-cesses along a river are governed by channel size especially channel width and depth as well as discharge The lsquoriver con-tinuumrsquo conceptualizes the downstream change in river

Figure 221 The island‐braided middle sector of the Tagliamento River in northern Italy Source Photograph by Geoff Petts

Figure 222 The sinuous single‐channel lowland sector of the Sacramento River California with important marginal lsquosnagrsquo habitat Source Photograph by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts

12 Freshwater ecosystems

morphology hydrology and energy flow as a sequence of biotic adjustments and patterns of organic matter utilization along the length of a river (Vannote et al 1980) Drainage area delineated by a topographic divide is the primary scale varia-ble for river systems Major changes occur at tributary junc-tions so that downstream trends in discharge and channel character are step functions reflecting the organization of the drainage network Drainage density the total length of chan-nels divided by drainage area is related to the effective precipi-tation (total precipitation minus evapotranspiration) The arrangement of channels within a drainage basin may be viewed as a hierarchy of lsquolinksrsquo Headwater streams are the external links that are terminated by the first tributary conflu-ence (= junction) Interior links are the channel segments between two junctions and their order or magnitude increases downstream depending upon the convention used One of the most useful conventions for ecological studies was introduced by Shreve (1967) whereby the magnitude of an interior link is equal to the sum of the magnitudes of the tributaries at its upstream junction which is also the sum of the upstream exterior links

River ecosystems are much more than simple linear features delimited by the bed and banks of the main channels and domi-nated by longitudinal downstream transfers They are three‐dimensional systems incorporating longitudinal lateral and vertical transfers of energy material and biota Lateral fluxes between a river its riparian zone and any floodplains and verti-cal exchanges between a river channel and the groundwater of the alluvial aquifer have important effects Particularly along once‐glaciated valleys sequences of alluvial basins separated by rock steps create the alternate downwelling and upwelling of river water into and out of deep valley‐fill sediments (Stanford amp Ward 1993)

The fluvial hydrosystem

The integrity of this lsquofluvial hydrosystemrsquo (Petts amp Amoros 1996) depends on the dynamic interactions of hydrological geomorphological and biological processes acting in three dimensions over a range of timescales The valley floor is com-plex comprising the biotopes and biocoenoses of running water standing water temporary water groundwater and ter-restrial environments Each environment is dependent to a greater or lesser degree on connectivity with the active channel of the main river Along larger rivers temporal variations of river flows especially the wet‐season flows enable lateral move-ments of plants and animals from main channels into floodplain lakes and backwaters (Welcomme 1979 Ward amp Stanford 1995 Petts amp Amoros 1996) In turn the active channel has an eco-logical character that reflects the interactions with those envi-ronments A segment of valley floor with a consistent structure may be described as a lsquofunctional sectorrsquo (Petts amp Amoros 1996) and in reality on most rivers the river continuum com-prises a series of functional sectors separated by major tributary junctions or changes of valley gradient and width their length being related to the size of the river ranging from 107ndash8 m2 on large rivers such as the Tagliamento Italy and Sacramento California (Figs 221 and 222) to 104ndash5 m2 along small streams (Fig 223) Each functional sector is characterized by a particu-lar diversity and arrangement of habitats reflecting the channel dynamics and strength of lateral and vertical fluxes over time-scales of 1 year up to 101ndash3 years

The fluvial hydrosystem concept and more recently the river ecosystem synthesis (Thorp et al 2008) shows how the distribution of species and ecosystem functions and processes is founded on the hydrogeomorphological characteristics of rivers Three fundamental hydrogeomorphological principles

(a) (b)

Figure 223 The highly mobile steep sediment‐loaded mountain sector of the Tagliamento River in northern Italy (a) contrasts with (b) a stable chalk stream the Wallop Brook in southern England Source Photographs by Geoff Petts