jharold

Rectangle

_ .•-_ ., •• , .... CJ... . I-I

AN INTERNATIONAL CENTRE

FOR

MANATEE RESEARCH

Report of a Workshop held

. 7 - 13 February 1974

Georgetown, Guyana

South America

Cosponsors :National Science Research Council (Guyana)

National Academy of Sciences (USA)International Development Research Centre (Canada)

Resumo·em Portugues

Resumen en EapaYfol

Reaume en Franfaia

NAS-NAE

JUN 3 1975

LIBRARY

The National Science Research Council Georgetown, Guyana 1974

Copies of this report are available without charge(while supplies last) from

Dr. Dennis IrvineVice ChancellorUniversity of GuyanaBox 841Georgetown, Guyana

W.H.L. AllsoppAssOCiate Director (Fisheries)International Development Research CentreP.O. Box 8500Ottawa KIG 3H9Canada

Noel D. VietmeyerProfessional AssociateNational Academy of Sciences2101 Constitution Avenue (JH 215)Washington, D.C. 20418

ii·

PREFACE

Aquatic vegetation causes serious problems for~ublic health, ftsheries, irrigation, transportation,and hydro-power generation in many tropicalcountries. Aquatic weed management and utilisationwas the subject of a workshop held in Georgetown,Guyana, in March 1973, jointly sponsored by theNational Science Research Council of Guyana andthe National Academy of Sciences (USA). Thisworkshop recommended, inter alia, exploring thepotential use of manatees (Trichechus spp) for controlof aquatic weeds in view of their voracious andrather indiscriminate consumption of aquatic vege­tation.

Manatees are, however, in danger of extinction.They can become important for weed clearance intropical waters only if their numbers are increasedgreatly. Survival and utilisation depend on increasingour knowledge of their reproduction, nutrition, andpathology to establish reliable methods of breedingand husbandry. Accordingly, a second workshop wasconvened to examine the need for, and feasibilityof, establishing a Centre for manatee research; and,if such a Centre were justiftable, to indicate possibleorganisational structures and modes of operation.This second workshop, sponsored jointly by theNational Science Research Council of Guyana, theNational Academy of Sciences (USA), and theInternational Development Research Centre (Canada)met in Georgetown, Guyana, 7 - 13 February 1974.Forty-six participants from twenty-three institutionsin eight countries were involved.

The deliberations in Georgetown occupied three2-day stages. In the ftrst stage technical discussionscovered background information on manatees, aquaticweeds, and manatee-protection legislation worldwide.Research programmes on behaviour and ecology.nutrition, reproduction, general physiology. anddomestication were outlined.

iii

Complementing these deliberations, the secondstage incorporated several fteld observations ofmanatees; demonstrations of weed clearing bymanatees; a fUght over the coastal region of Guyana:boat trips to observe natural manatee habitats andpotential sites for a manatee research Centre; andvisits to the University of Guyana, the Georgetownwater works, the Museum, and Zoological Park.

Following this preparation, the third stage consistedof deliberations that led to the workshop's consider­ation of possible models for the structure of theCentre. After agreeing to recommend the establish­ment of a research centre, the workshop nominatedProfessor E.C. Amoroso, C.B.E., F.R.S., to chair anInterim Steering Committee to organise the researchcentre's establishment.

Workshop participants made speciftc suggestionson funding and facilities - including site require­ments, future actions, a scheme of phased develop­ment, as well as detailed lists of needed experimentsand basic equipment. The workshop participantswelcomed the address by the Hon. Dr. Ptolemy A.Reid, at the time acting Prime Minister of Guyana,\Yho stressed the desire of his Government to supportfully the activities of a manatee research centre. Heemphasised that the long-established interest inmanatees in Guyana argued favourably for locatingthe Centre in Guyana. He further indicated thatGuyana would be prepared to offer adequate landand to provide other services and facilities thatwould enable a centre to operate effectively andpursue serious scientiftc research in association withGuyanese laboratories and institutions, and still haveautonomy and international liaison.

CONTENTS

Summary

RESUMO EM PORTUGUES

RESUMEN EN ESPA~OL

/ "RESUME EN FRAN\AIS

Chapter I Manatees

2 Manatees and Aquatic Weeds

3 An International Centre for Manatee Research

4 Suggestions for the Centre's Research Programme

Appendix A List of Participants

B Acknowledgements

C Guyana

D Selected Readings

iv

SUMMARY

Tropical food production is often directlyhampered by aquatic weed infestation in riven,man-made lakes, and irrigation schemes. The weedsimpede navigation, irrigation, drainage, and hydro­electricity production.

Manatees may offer a significant approach toovercome this problem. Native to more than 40tropical countries of the Americas and Africa,manatee900r sea cows are the world's only herbivorous,totally aquatic mammals. Their voracious appet~te

for plants has been turned to good use in Guyana,South America, where they· have been introducedinto canals and have effectively cleared aquaticweed infestations.

Manatees might, in future, prove to be importantfor aquatic weed control throughout the tropics,since many tropical waters in Africa, Asia, and theAmericas are climatically suitable for them. Therecould be a consequent impact on water-borne diseases,drainage and irrigation, hydroelectric schemes,transportation, and fIShing. At the same time,manatee meat is highly prized and holds promiseof contributing to food supplies.

But manatees are almost extinct and their usewill only become practicable when their reproductionand numbers are adequately assured and the dangerof extinction is removed.

Scientists· from 8 countries, representing 23research institutions, considered comprehensively thestatus, utility, conservation, and biology of manatees

at a workshop held in Guyana 7 - 13 February 1974.The participants included internationally recognisedscientists with experience and knowledge encompass­ing manatee research, mammalogy, veterinary science,reproductive physiology and endocrinology, wildlifemanagement, nutrition, organisation of scienceinstitutions in developing countries, operation ofinternational organisations, and the utilisation ofmanatees for weed control.

It was concluded that research on manatees isurgently needed and is critical to the survival andutilisation of the species. Intensive involvement isreqUired of a wide range of scientific disciplinesincluding physiology, ecology, behaviour, and con­servation. This can best be accomplished throughestablishment of a relatively small international centrefor manatee research. Despite some difficulties Guyanaoffers incomparable opportunities as a location forsuch a manatee research centre.

Objectives of the proposed research centre includeincreasing manatee numbers, promoting their con­servation and husbandry, investigating the use ofmanatees for aquatic weed control, and food, aswell as contributing to mammology and tropicalscientific research.

An interim steering committee has been appointedto consider the institutional structure and actionsnecessary to establish and operate a manatee researchcentre.

RESU~10

A produ~ao de alimentos nos parses tropicais ~

muitas vezes dificultada por infesta~()es de ervasdaninhas nos rios, represas e projetos de irriga~ao.

Estas ervas daninhas impedem a navega~ao, irriga~ao,

drenagem e produ~ao de energia hidrel~rica.

o manatim podeli vir a solucionar este problema;tern 0 seu habitat natural em mais de 40 parsestropicais na Arn~rica e na Africa. Os manatins oupeixes-boi sao os dnicos mamlferos herbi'voros total­mente aqu4ticos. 0 apetite voraz do peixe-boi porplantas aqu4ticas j4 foi utilizado pela Guiana, naArn~rica do SuI, na desoljstru~lIo de canais.

Os peixes-boi poderao vir a ser importantes nofuturo para 0 controle de ervas daninhas aqu4ticasnos tr6picos, visto que se poderiam aclimatar emmuitos rios na Africa, Asia e nas Arn~ricas. Tamb~mpoderiam ter un consider4vel impacto sobre doen~as

transmitidas pela 4gua, drenagem, projetos hidre­l~tricos, transporte aqu4tico e pesca. A came dopeixe-boi ~ altamente apreciada e poderia vir acontribuir no suprimento de alimentos.

Atualmente os peixes-boi estao quase extintose sua utiliza~ao s6 se tomar4 vi4vel quando suareprodu~ao e ndmeros estiverem devidamente asse­gurados e fora do perigo de extin~ao.

Cientistas de oito parses, representantes de 23institui~()es cientnicas de pesquisa estudaram a fundoo problema da utilidade, conserva~ao e biologia dopeixe-boi, numa reuniao realizada na Guiana de7-13 de fevereiro de 1974. Entre os participantes

2

encontravam-se cientistas de renome mundial, peritosno campo de pesquisa sobre 0 peixe-boi, estudossobre mamlferos, ciencias veterinuias, fisiologia eendocrinologia do sistema reprodutivo, manejo dafauna, nutri~ao, organiza~ao de institui~()es cientnicasem parses em desenvolvimento, funcionamento deorganiza~oes intemacionais, e a utiliza~ao do peixe­hoi no controle as ervas daninhas.

Chegou-se Aconclusio de que devem ser realizadasurgentemente pesquisas sobre. 0 peixe-boi, deimportancia decisiva para a sua sobrevivllncia eutiliz~iio. Necessita-se de ampla participa~ao deuma s~rie de outras disciplinas cientnicas, tais comoa fisiologia, ecologia, comportamento animal, e con­serva~io. Pode-se atingir melhor este objetivo criandourn pequeno centro de pesquisa sobre 0 peixe-boi.Apesar de algumas dificuldades, a Guiana ofereceexcelentes perspectivas para a constru~ao de talcentro.

Os objetivos do referido centro abrangerao estudossobre 0 aumento do ndmero de peixes-boi, conser­va~ao, reprodu~ao, e pesquisas sobre a sua utiliza~ao

no controle as ervas daninhas, e 0 seu aproveitamentocomo fonte de alimentos; outrossim, 0 centrotemb~m contribuir4 no setor de estudos sobremamlferos e pesquisas cientfficas nos parses tropicais.

Foi eleito em car4ter interino urn comit~ diretivopara estudar a estrutura institucional e medidasnecessmas para estabelecer e administrar urn centrode pesquisa sobre 0 peixe-boi.

RESU~lEN

Con frecuencia la producci6n de alimentos trop­icales se ve directarnente impedida por la proliferaci6nde hierbas malas acu4ticas en dbs, lagos artificialesy sistemas de regadro. La hierba mala impide lanavegaci6n, el regadro, la desecaci6n y la producci6nhidroel6ctrica.

Los manatres pueden representar una excelentesoluci6n para eliminar este problema. Oriundos demlls de 40 parses tropicales de las Amt!ricas yAfrica, los manatres 0 vacas marinas son los tinicosmamiferos herbi'voros totalmente acu4ticos. Su vorazapetito por las plantas se ha utiIizado con t!xito enGuayana, Sudamt!rica, donde se les ha introducidoen canales para limpiar en forma efectiva las aguasinfestadas de hierbas malas acu4ticas.

EI manati puede resultar en el futuro un elementoimportante para el control de hierbas acu4ticasen los tr6picos debido a que muchas de las aguastropicales en Africa, Asia y las Amt!ricas son propiciasclim4ticamente para estos animales. Podrran ejercerun gran impacto en las enfermedades acu4ticas,sistemas de riego y alcantarillado, sistemas hidro­elt!ctricos, transporte fluvial y pesca. AI mismotiempo, e' precio del manatr es alto y representauna fuente de alimento.

Sin embargo, el manatr est4 casi extinto y suutiIizaci6n solamente podr4 ser practicable cuandosu producci6n y m1mero estt! asegurada en formadebida y se haya eliminado el peligro de su extinci6n.

Cientitlcos de 8 parses, en representaci6n de23 organizaciones de investigaci6n, consideraronampliamente el estado, la conservaci6n y la biologfa

3

de los manatres en un simposio celebrado en Guayanadel 7 all3 de febrero de 1974. Entre los participantesfiguraron cientmcos de fama intemacional con exper­iencia y conocimiento sobre investigaciones acercadel manatr, animales mamiferos, sicologra veterinariay endocrinologra reproductiva, conservaci6n de lafauna, nutrici6n, organizaci6n de instituciones cientf..ficas en parses en desarrollo y utiIizaci6n de losmanatres para el control de hierbas acu4ticas.

Se lIeg6 a la conclusi6n que la investigaci6n sobreel manatr es un aspecto urgente y crftico para lasupervivencia y utiIizaci6n de la especie. Se requiereuna extensa labor en una serie de disciplinascientmcas, incluyendo fisiologra, ecologra. compor­tarniento y conservaci6n. Esto SP. puede llevar acabo en la mejor forma posible. estableciendo uncentro internacional, relativamente pequeno, para lainvestigaci6n del mllllati'. A pesar de algunas dificul-·tades, Guayana ofrece oportunidades incomparablescomo lugar para establecer dicho centro de investi­gaci6n de los manatres.

Los objectivos del centro de investigaci6npropuesto abarcan el aumento del m1mero demanatres, la promoci6n de su conservaci6n y prod­ucci6n, la investigaci6n del uso del manatr para elcontrol de hierbas malas acu4ticas, y como alimento,contribuyendo ademlls a la investigaci6n cientificatropical y de animales mamiferos.

Se ha formado una comisi6n interina de iniciativaspara considerar la estructura institucional y lasdisposiciones necesarias para constituir y operar uncentro de investigaci6n de los manatres.

RESUME

Dans les pays tropicaux, les cultures vivri~res

sont souvent mises en ~chec par l'envahissementdes cours d'eau, des lacs artificiels et des r~seaux

d'irrigation par des herbes aquatiques. Ces derni~res

contrarient la navigation, I'irrigation, I'~coulement

des eaux et la production de houille blanche.

Le lamantin, Ie seul mami~re herbivore com­pl~tement aquatique, qui est aborig~ne dans plus dequarante pays tropicaux de l'Am~rique et del'Afrique, pourrait offrir une d~marche significativevers la solution de ce probl~me. On a mis aprofit son ap~tit vorace pour les v~g~taux. enGuyane (l'ancienne Guyane anglaise) ou il a ~t~

introduit dans des canaux qu'il a efficacementd~barras~s d'herbes aquatiques prolif~rantes.

Dans I'avenir, les lamantins pourraient se r~v~er

un important facteur permettant de contenir l'envah­issement des herbes aquatiques de toutes les eauxtropicales. Ces derni~res, en effet, qu'elles soientd'Afrique, d'Amerique ou d'Asie, sont climatiquementfavorables a ces mami~res. Les cons~uences surles maladies transmises par l'eau, sur I'~coulement

des eaux et l'irrigation, sur les projets de productionde houille blanche, les transports et la peche,pourraient etre consid~rables. En outre, la chairdu lamantin est tres estim~e et pourrait apporter sacontnbution comme ressource a1imentaue.

Malheureusement, les lamantins sont en voied'extinction et leur utilization ne deviendra possibleque lorsqu'on aura pu assurer leur reproduction enassez grand nombre pour garantir que Ie danger dedisparition n'existe plus.

Des savants de huit pays, repr~sentant 23~tablissements de recherche, ont examin~ de fa~on

approfondie la condition, l'utilit~, la protection et

4

Ia biologie des lamantins a un colloque qui s'esttenu a Georgetown, en Guyane, du 7 au 13 f~vrier

1974. Parmi Ies participants se trouvaient des savantsmondialement connus pour leur ex~rience et leursavoirsur la recherche sur Ie Iamantin, la mammalogie.la science v~t~rinaire, Ia physiologie de Ia reproductionet l'endocrinologie, Ia protection de la nature, lanutrition, l'organisation d'~tablissements scientifiquesdans les pays en voie de d~veloppement, la gestiond'organismes internationaux et I'usage du lamantinpour contenir Ia prolif~ration des herbes aquatiques.

A l'issue du colloque on a d~ciM que la recherchesur Ie lamantin ~tait absolument n~cessaire et urgel1teet qu'elle ~tait vitale pour la survie et I'utilisationde l'espece. Ce qu'il faut c'est I'al'pui sans r~serve

de toute une gamme de disciplines scientifiques, ycompris Ia physiologie, I'~cologie. I'~tude du com·portement animal et la protection de la nature. Lameilleure f~on d'atteindre ce but serait la cr~ation

d'un centre international, relativement restreint, derecherche sur Ie lamantin. En d~pit de quelquesdifficult~s, la Guyane offre des possibilit~s exception­nelles pour I'~tablissement d'un tel organisme.

Parmi les objectifs du centre propos~ on rel~ve :l'accroissement de la population des lanlantins, leurprotection, leur ~levage, la recherche sur leurutilisation, non seulement pour eorayer la prolif~r­

ation des herbes aquatiques, mais aussi commeressource alimentaire et, enfin.· une contribution aIa mammalogie et a la recherche scientifique surles pays tropicaux.

Un comit~ int~rimaire de direction a ~t~ mis enplace pour examiner \a structure institutionnelle d'uncentre de recherche sur les lamantins et les mesuresn~cessaires a son ~tablissement et a sonfonctionnement.

CHAPTER 1

~lANATEES

Manatees are believed to share a common ancestrywith elephants, dating back to the Eocene period,50 million years ago. They were first described byColumbus during his first voyage, whose diary forWednesday 9 January 1493 contains the following:

...On the previous day, when the Admiralwent to the Rio del Oro, he saw threemermaids, which rose well out of the sea;but they are not so beautiful as they arepainted, though to some extent they have theform of a human face ... 1

Manatees belong to the order Sirenia which hastwo families, the Dugongidae (dugongs), with onespecies, and the Trichechidae (manatees), with threeliving species: 2 the Caribbean manatee, Trichecllusmanatus; the Amazonian amantee, T. inunguis; andthe African manatee, T. senegalensis. Manatees arestrictly tropical (see map, FIGURE I). The Caribbeanmanatee is native to Florida and to the Gulf, Caribbean,and Atlantic coasts of Central and South Americafrom Mexico to central Brazil. It is also widelydistributed in the West Indies. The Amazonianmanatee is confmed to the Amazon River and itstributaries. The African manatee is found on thewest coast of Africa from Senegal to Angola, mainlyin the Senegal, Niger, Benue, and Congo river systems.

1. Bourne, E.G. 1906. Journal of the First Voyageof Christopher Columbus (1492 - 1493). In TheNortIunen, CoIumbu and Cabot 985-1503 AD.Scribners, New York pp. 77-80.

2. The literature reports that the manatee native toFlorida, USA, is a distinct subspecies of T. manams,but this is doubted by modem researchers.

5

In the past, the three species of manatee werenumerous, even abundant, along the shores and/orin the rivers of a score of countries on both the westand the east sides of the tropical Atlantic Ocean(see list, TABLE 1). Today, it is difficult to locatemany places in those countries where a manatee canbe readily seen in the wild. A notable exception isa small group of manatees that seasonally congregatein the clear water of the Crystal River in Florida(FIGURES 3, 4). This circumstance and the clarityof water there has enabled scientists to study thesemanatees in more detail than any others in the world.

Elsewhere, where once there were gregarious herds,populations have been so reduced, and in mostplaces so endangered, as to 1,1: on the verge ofextinction. The sight of one of these now shyanimals is a matter of good fortune.

The largest known residual populations ofmanatees .are the few hundreds in Florida waters,the fair numbers in the small territory of Belize,and the larger total (but probably less dense presence)in the much bigger Guyanese region.

Man appears to be their only predator; huntingis the majo{ cause of their decline. Their meat hasoften been praised for its delicacy, flavour, andkeeping qualities when salted or preserved in itsown fat. Furthermore, 85 percent of the carcass canbe used because, in addition to the meat,

The skin can be processed into a tough leather;

The blubber yields a clear, pleasant-flavouredoil; and

The rib bones can be highly polished andused as a substitute for ivory.

FIGURE 1 The _Idwide distribution of mMMt_.

ATLANTIC

OCEAN

m Trichechus mansrus

t'\\~l Trichechus inunguis

F",,:v,1 Trichechus SflrHI(JIIlersis

AFRICA

WORLDWIDE DISTRIBUTION OF MANATEES

Trichechu. manama Trichechu...n","'"

Country

U.S.A.

Mexico

Belize

Guatemala

Honduras

Nicaragua

Co~ta Rica

PanamaColombia

Venezuela

Guyana

Surinam

French Guiana

Brazil

Curacao

Cuba

Jamaica

SpeclfIc Ioc:aUon cited inrecent decades

Florida

Yucatan Peninsula

Rivers,e.g.,Belize River

Peten region

Canllbean coastal region

Caribbean coastal region;Bluefield RiverLimon Province

Caribbean Coast

Lake Maracaibo, lowerOrinoco

See elsewhere in this report

Coastal region

Coastal region

Coastal rivers in theNorth East

Country

Senegal

Gambai

PortugueseGuinea

Guinea

Sierra Leone

Liberia

Ghana

Ivory Coast

Togo

Dahomey

Mali

Nigeria

Specific Ioc:ation cited inrecent decades

Mulgots from Senegal River south

Casimance Region

Gambai River

mangrove swamps

Volta River (above and below thedam); probably lower reaches ofother rivers

Cavally River; probably lowerreaches of other rivers

Segou, Lac Debo, Timbuktu,Ansongo, Gao

Mouth of the Niger River, Calabar;Coastal rivers in Western and Mid­western regions; Benue River e.g.at Numan

Haiti

DominicanRepublic

Puerto Rico

Other CaribbeanIslands

Colombia

Pcru

Venezuela

Guyana

Brazil

Trichechus u..JlIIIis

Putumayo-Leticia Regions

Putumayo, Napo, T~re,

Maranon and Ucayali Rivers

Orinoco headwaters

Rupununi and Essequibo

headwaters (not confirmed)

Lower reaches of Amazon

main tributaries, e.g.,

Nhamunda, Tapajos Rivers

Chad

Cameroon

Rio Muni

Gabon

COI1l!0

Zaire

Cabinda

Angola

Lake Lere and Benue River

Maogrove regions

Lower reaches of Gabon andOgooue Rivers

Kouilou River

wwer Zaire (Congo) from Bananato Chaudron d'Enfer, especiallyround Boma

Coastal rivers north of the Cuanza

TABLE I

7

FIGURE 2 Holding several plants between flippers, a manatee feeds on water hyacinth. Spurning the roots, manatees .atthe green, aerial parts, killing this, the world's most devastating aquatic weed. They prefer more succulant vegetation ifavailable. (Hartman)

FIGURE 3 Dappled with sunlight, a large manatee swims in the water of Crystal River, Florida, one of the few places in theworld where the animals can be seen in the natural state in clear water. Measuring up to 4 m long, manatees can weigh up to500 kg. With their powerful tails they are strong swimmers. (Hartman)

8t E' y(~oogle

FIGURE 4 BeI~", on its tMI•• m-tee~ • pit from • _imlMl' It Crystal River. Floridl. Som. 1IIIIIIt_ h..Mnbecome .-y ....,. end court the intMwt of _imm..... Fingerneill on flippin .re .n indicltion of their terrwtri81 '~Ortend ... teeture lIIId to dlttinguilh T. inungu'-. the Amuon mII_. (which lICks theml. from the other two 'PICaFWty. brittle -.red. lipI .. indep.nd....t1y movlllbl••nd ..utili to "brulh" food into the mouth. (Powell!

Because of the many products derived frommanatees, they have been much exploited. Intensiveslaughter in the Caribbean commenced with theSpanish colonists, who relished the meat and wereallowed to eat it on religious fast days, and thebuccaneers, who utilized it on extended voyagesand expeditions.3 Later, manatees were used toprovide meat for workers in the new sugar plantationson the Caribbean islands. Trade in manatee hidesand meat was active on the Amazon River, at leastuntil 1945; in one 2-year period early in thiscentury more than 8,000 were slaughtered4 By1964 it was reported that manatees had disappearedfrom many of the lower reaches of the Amazon.SIn the early 19305 it was reported that hunting

3. Elquemeling. 1678; Dampier. 1729. (See SelectedReadings, p.33 .)

4. Personal communication from P.A. Machado to thewo.kshop.

S. Crowe P.K. and I.R. Grimwood. 1972. Reportedin Red Data Book VoL 1 (Mammalia). (Page code17.116.1.2 E) International Union for theConllCrvation of Nature and Natural Resources,1110 Morges, Switzerland.

9

had all but exterminated manatees in the Congo,Gabon, and most ofcoastal Nigeria.6

Manatees are legally protected in almost everycountry in which they occur, but in remote areasenforcement of the law is ineffective. Furthermore,habitat destruction, wounding by boat propellers,and accidental drowning in nets are increasinglyserious threats to survival. That there is little scientificknowledge about manatees also makes theirconservation more difficult.

Scientific literature mainly describes the anatomyof various museum specimens and the palaeontologyof fossil remains. A few recent papers deal withecology, behaviour,physiology, and pathology. Know­ledge of the animal's reproduction, digestion, res­piration, circulatory and excretory processes, itspopulation dynamics, and nutrition is relativelyinsignificant.

Manatees and dugongs are the only totally herbi-• vorous aquatic mammals. Their ability to convert

plants to meat places them in the same category ascattle - hence the common name "sea cow". It is

6. Hatt. 1934. (See Selected Readin~. p. 33·)

Digitized by GoogIe

particularly lipliflcant that they sraze one of themOlt underutililed food resources: aquatic plants.Voracious feeders, they may consume u much u20 percent of their body weight per day.

Manatees are remarkably nonselective in theirchoice of food. They prefer succulant vegetationbut, if denied it, will consume almost any availableaquatic or terrestial plants. Unlike the exclusivelymarine dugong, manatees move freely between freshand salt water. The Amazon species of neceuityUves exclusively in fresh water; the odlers seem toprefer riven and estuaries to the sea, but theirOImoregulatory (salt-b~ance) mechanisms have notbeen investigated.

Manatees are by nature slow-moving, shy,unobtrulive, and wary of anything nonaquatic. Never­theless, they have proven docOe and tractable incaptivity. Some have appeared to show affectionfor divers; humanely treated, they can developclose Ulociations with man. They are ealily con­ditioned; in Guyana in both the Botanic Gardensand the Water Works they come to the same locationswaiting to be fed lawn cUppings (FIGURE 5). Duringthe day they respond to the noise of the garden~r

sharpening his scythe and swim to the adjacentbank. In Florida they have also been trained to doIUch simple tricks u swimming through a hoop.

Florida manatees seem to have no diltinct breedingseuon. A female in oestrus II followed by many

males. Such a "mating herd" penilts from 2 • 4weeks, but the female II receptive only brieflydUring this period. Copulation is horizontal, usuallyin water deeper than 2 meters. During the period ofreceptivity the female II pronUscuous. The presenceof several males at oestrus may be a stimulus fornormal reproductive responses in the female.

Gestation in T. manatusluts more than 152 daysand may be u long u 13 months.' Twins areextremely rare. The calf II born in the water, andthe mother pushes it to the surface 10 it can takeits flrst breath. The newborn rides on her back, andover a period of hours she conditions it to divingby submerging it for succeuively longer intervals.Calves are IUckled at teats located at the junctionof the flippers and body. Mother and young cansubmerge in perfect coordination whOe IUckling.Maternal care luts for months and pOisibly for ayear or more.

The calf begins feeding on vegetation u earlyu one month old and intersperses suckling withsrazing untO weaning, perhaps u much u 2 yearslater. Manatees become sexually mature at 3 • 5yean of age.

7. Hartman. 1971. (See Selected Readlnp. p. 33.)

fiGURE l5 Th. BoUnio Gird",. In GlOI"fItOWn. GUYI. h. hid IIIIIlIteII on dilplly IInII the ,.... ''''1", ...0I1pp1"ll to dtIm hII bIaomI I trldltlon with Guy_ ahlldren. Man.-. .... no ...... the front of tMIr mouth. and.. not .......VI. IGuYInI Informltlon IIrvloll

10Dljlllej by C-;ooglc

CHAPTER 2

MANATEES ANDAQUATIC WEEDS

Infestation of aquatic weeds represents one ofthe mOlt serious and increuinslY recognized environ­mental problem throuahout the tropical world.Aquatic weeds blockwaterways and impede naviption,hydroelectric seneration, and fishing. They fosterwaterborne diseuet, curtail rice cultivation in fioodedpaddies, and render irrigation projects usele..(FIGURE 6). This lut is a mOlt serious concern inUsht of the current food shortages. If irrigation

water is scarce, the yield and number of crops thatcan be grown in a year can be drutically reduced.Althouah aquatic weeds cause serious damage intemperate climates, they create special difficultiesin the tropics where the warm waters encouragerapid growth. "Explosions" of aquatic weeds such uwater hyacinth (EkbhomJa CI'IlIIipeI), salvinia (SaMniaaaricuJata), and water lettuce (PiItIa ltrltiotel) haveoccurred in many tropical countries:

f1QURE. 0."..,", oountrt. un III Ifford wnrwlYI Intllt8d wltll 1qU8t1o ...... Here, In Indll, WI'" hYlOlntllIIIDlIa ................. I UM ....... to dillY" WIter to In ......... 'rr"lon 1IIhame. Wltfl no InlXpenlm, IfflOtlyeIOIutJon to til. prabllm many ""lui oountrt. .,. flOId wltll _taul lGOfIomlo '011 ........ bY ..,8tI....... 'ul1hlrmo....wtdI lnor-'", numblre of wI.r projlota In til. " ..101 tIl.'r "1IUt1", IffIOtI Ir. llrUln to lno...... In til. futur.. (ZIItI.,

11 Digitized by GoogIe

Appearing in the Sudan, water hyacinth wasreported in 1958 as infesting 1,000 km of theWhite Nile; it may have attained this spreadwithin a year.8

Introduced into Ceylon in the early 19505,salvinia covered 8,800 ha of flooded ricefields and 800 ha of waterways within about12 years.9

Water hyacinth was first reported in the lowerZaire (Congo) River in 1952; 3 years later ithad reached Stanleyville (Kisangani) 1,600 kmupstreaIll. Today, some Zaire tributaries areimpassable to small boats, and some riverinecommunities have had to be abandoned. In1957 it was reported that (despite a U.S. $1million control project) water hyacinth floatedpast Leopoldville at a rate of 136 tons/hour. lO

In India, some expensive irrigation schemesconstructed in the last decade have becomeso choked with weeds that the water flow iscut by 80 percent (FIGURE 6). Some of thesecanals are hundreds of kilometers long and,if unobstructed, could irrigate hundreds ofthousands ofhectares, rrodUcinglarge quantitiesof much needed food. 1, 12Water hyacinth reached Bengal in the 19205.Today, it is estimated that water hyacinthprevents the cultivation of 12,000 ha of landin West Bengal and uncounted thousands ofhectares in Bangladesh.11Thousands of hectares of waterways in thesouthern United States are infested with aquaticweeds. In 1949 it was estimated that inLouisiana

under good growing conditions, a matmigrates at the rate of 2 ft. per month and

8. Gay, P.A. 1960. Ecological studies of Eichhorniacruaipea Solms. in the Sudan. I. Analysis ofSpread in the Nile. Journal of Ecology 48:183-91.

9. Williams, R.H. 1956. Salvinia auriculata Aublet:the chemical eradication of a serious aquatic weedin Ceylon. Tropical Agriculture. 33: 145-57.

10. Lebrun J. 1959. Reported in Holm, Weldon andBlackburn. (See Selected Reading. p. 34.)

II. Tinker, J. 1974. Waterweeds: flies in the irrigationointment. New Scientist 61 :747-9.

12. Gupta. 1973. Aquatic Weed Control. RajasthanCollege of Agriculture, Udaipur, India.

12

the plants double their numbers every 2weeks by means of offshoots. At this rate10 plants would produce 655,360 plants(a solid acre) in one growing season (Mar.15 - Nov. 15).13

It was estimated then that the weeds were costingthe state of Louisiana up to 15 million dollarsannually.

In Florida water hyacinth covers some 80,000 haof the state's waterways and the cost of controllingaquatic weeds in the state has soared to $7 milliona year. Failure to keep the hyacinth in check couldrender Florida's rivers and lakes totally inaccessibleto navigation within a few growing seasons.l4

Problems in Aquatic Weed Control

Today, no single aquatic weed control methodis wholly effective. Methods suitable for tropicalcountries, in particular, are lacking. Aquatic weedscan be physically removed from the waterways; theycan be destroyed with chemicals (herbicides), eatenby animals (notably manatees, herbivarous f,m, andinsects), degraded by microorganisms, or displacedby species of less harmful plants. I5

Biological controls are being studied but holdlittle hope for widespread, immediate use. Herbicidesare available, but some have come under attackbecause of side effects on other species, and thetremendous cost of such aquatic weed control. Themost effective commercial herbicide, 2,4-0, costsUS$60 - $120 per ha to apply. Almost all developingcountries, therefore, are forced to use physical removalas a weed-control measure. But this, too, is expensiveand has drawbacks. For example, in India's Chambalirrigation system in Rajasthan State, the main canals(blocked up to 50 percent) and feeder canals (blocked80 percent) have to be closed for weed clearingonce a year. This reduces the number of annual cropsthat can be grown from three to two. I I In othercountries schistosomiasis and other waterbornecHseases, or such unpleasant fish as electric eels,make this method less than ideal.

13. Penfound, W.T., and T.T. Earle. 1948. The biologyof the water hyacinth. Ecological Monographs18(4 ):44 7-72.

14. Personal communication. Aquatic Weed ControlDivision, Florida Game and Fre h Water FishCommi sion.

IS. For a summary, see Some Prospects for Aquatic:Weed ManlF'Rent in Guyana (See SelectedReadings, p. 34.)

Dljlllej by C-;ooglc

Manatees for Weed Control

It is abundantly clear that all methods oftropical aquatic weed control urgently needgreater attention by the international scientificcommunity. Yet Guyana is the only countryin which manatees have been used for deliberateweed control; in the past 20 years over 200manatees have been utilized and have provedhighly effective.

In 1916, according to the Guyana NationalArchives, manatees were used for weed clearingin sugar-estate canals, but the practice apparentlywas not continued. In 1951 the GeorgetownWater and Sewage Works built a water reservoirand settling basin (FIGURE 7), and J.Richardson, Deputy Chief Engineer, GeorgetownSewage and Water Commissioners, reported thefollowing experiences to the workshop:

Within 6 weeks of constructing the earth­bottomed canal the quantity of aquatic weedsbecame so great that the flow rate dropped to

less than 1 m per minute, and the water over­flowed at the input end. Four men were put towork clearing the 600m long, 12 m wide canal.ajob that took about 10 days. Within 2 months,the problem was back again.

In 1952 four manatees were introduced intothe canal in a weed-control experiment. Weedsdisappeared in about 8 weeks, and the manateessoon had to be fed with grass cut from thesurrounding lawns. The government bacteriolo­gist tested the water and declared that theextent of contamination by the manatees wasnot beyond the capacity of the nonnal sterilizingequipment of the fmal stages of the water­treatment plant.

During the 22 years the manatees have beenin the canal there has been no weed problem.In this period three manatees have been replacedas they died.

The year 1972 began with only one manateewho alone easily kept the weeds down in a

FIGURE 7 The Georgetown Water and Sewer. Works, Guyana: Manat_ have kept thl. waterway weed fr.. for 22 y..rs.Weed regrowth in this 400 m long, 10 m wide canal it inlUfficient to ..stain even OM manat..; tIM one in here h. to be fedcllppinga daily. Note the clunly cropped adgn. (Vietmeyer)

13Digitized by GoogIe

FIGURE 9 Before 1959 when two maNlt__re placed in this Thr. Friends Canal 1_ GuyaNl map. FIGURE 81 it lookedlike this and annually cOlt $1.500 IU.S. $7601 to cl.r.....

360 m long section of the canal. This animaldied, however, and within a month the originalweed problem was back. Two animals werethen purchased for G$2oo.oo (US$loo) each,and the weed problem was again solved.

In the mid·1950s the Drainage and IrrigationDepartment and Bookers Sugar Estates sought waysto control aquatic weeds in the canal system ofGuyana. With the increasing use of fertilizers in caneand rice farming, aquatic weeds flourished, and theincreasing use of herbicides to control them beganto cause concern among the rural population, whichused the water for domestic purposes. From 1959to 1962 approximately 80 manatees were introducedinto canals to test their weed-clearing ability. In1962 the following results were reported: 16,17

Four manatees cleared the Ruby/BoerasirieDistributary (surface area 3.1 hectares) of

i6. Report on the Use of the Manatee in the Controlof Undesirable Weeds in Drainap and lIqjationCanals in British Guiana. 1962, Mineographedinternal report issued by Agriculture and Draillll8el

14

Cabomba aquatica, Nelumbium speeiosum,Paspalum repens, and Utricularia foliosa.Four manatees could not eat all the Cabomba,Nelumbium, and Luziola spruceana in theWales/Georgia Distributary (surf~ce area; 9 ha).Two manatees found the quantity of weeds inthe Craig Distributary (0,7 ha) insufficient andhad to be transferred elsewhere.Four manatees .kept another section of theCraig Distributary (3.1 ha) clear, but Paspalumvergatum persisted at the fringes.Four manatees cleared the Garden of EdenDistributary (5.7 ha), though regrowth ofPaspalum repens was very rapid.Three manatees kept the Black Bush Polderchannels (2.2 ha) free of aquatic plants.Two manatees placed in the Three Friendscanal (3.8 ha) in 1959 cleared it of Cabomba,Luziola, and Hymenacbne amplexicaule andhave kept it clear since then (FIGURES 9, 10).

Irrigation Departments. Reported by Allsopp. 1969.(See Selected Readings, p. 33.)

17. For locations see map, FIGURE 8.

Digitized by GoogIe

FIGURE 10 •••. In the 16 yu,. since tINt time nothing h. bNn IIMnt on WHd control. Tod8Y.the caMI h. thru INlnat_(one of the first c_ of e birth in Mmi-confinementl end it looks like thi•. (Works end Communicetion. Ministry, Guyenat

In 1962 it was noted that the pair had increasedto four, one of which has subsequently died.

This canal has not only been clear of weeds duringthe IS-year interval since the manatees were intro­duced. but has required no expenditure for weedclearing and no maintenance of the manatees. Before1959 weed clearing in this canal cost $1500 (US$7S0)per year; since then nothing at all has been spent onit.

It should be recognized that in these experimentsthe manatees were placed in weed-infested waterwaysand the ateas represent their weed-clearing ability.It is not known what area of water a manatee canmaintain weed free if it must eat regrowth only, butit must be much greater than the figures quoted.

Manatees appear to be very systematic as weed­clearing agents. They begin at a point in the weedpatch and move in consort, eating at the edges untilthe patch is consumed. Canal banks are clearedright up to the soil line (FIGURES II, 12), butthere is no erosion damage due to interference withthe soil.

IS

Advantages

Manatees have many advantages as weed-controlIlgents. They are docile, unobstrusive, and harmless toman. They are rather unselective in the food theyaccept, though they prefer submerged and softerplants. Manatees adapt readily to confinement whenprovided with adequate food, and can survive intropical waters whether fresh, saline, acid, alkaline,turbid, or clear. If undisturbed, they remain passiveand immobile when out of water (FIGURE 13). Thus,compared with other wild animals of their size andweight, they are fairly easy to transport.

Sometin.es called sea cows, manatees convertaquatic plants into protein that could be used forhuman consumption. Perhaps it is not too far-fetchedto note that a single manatee can furnish as muchmeat as a steer; it can gain weight as rapidly, is aseasily cared for, and may prove to be less expensiveto rear. Manatees could tum to benefit waters thatnow are unproductive and, at the same time, relievethe destruction and disease caused by weeds.

Digitized by GoogIe

FIGURE 11 This ClInal in the Botanic Gardens. Georgetown, Guyana, exemplifies the infestation of rooted aquaticWMds las opposed to floating weeds, as in FIGURE 61 in Ihallow tropical waterways. It should be compared with....

FIGURE 12 .... A neighbouring canal in which a manatee has been plac:ed for the purpon of weed control. IVietmeyarl

16

Dljlllej by C-;ooglc

,r

FIGURE 13 Manatea can be kept out of water for days if nac_ry, but their skin must be kept moist. Compared withother wild animals of their lize manat_ are lI8IY to handle; if Undisturbed, they remain motionless when out of water.Duril1ll 20 years Oatakaran Jeetlall has captured from one stretch of Guyana's Abary River over 70 manat_ for weed-controlprogrammes. (Guyana Information Servicesl

I,Before biological control agents are introduced

into a new area, they must be thoroughly investigatedfor possible undesirable side effects on plants andanimals. Manatees. however, because of their size,and restriction to waterways, make it unlikely thatthey will become problems themselves.

Disadvantages

Manatees do have some disadvantages as weed·control agents. They breed poorly in confined areasand have a slow rate of reproduction even in thewild. They also present other difficulties:

Because of their docility and their habit ofreturning to the same weed patch day afterday. manatees are highly vulnerable to poachingand vandalism, particularly in narrow channels.They can easily be injured or even killedunless special care is taken in their transport.Because of their strength they are not easy toconfine in a given waterway. and precautionsmust always be taken to prevent manatees fromentering culverts, sluices, or lock gates where.without access to air, they drown.

17

In navigable waterways manatees can be fatallyinjured by boat propeller.;.Once established, they are not easy to locateor recapt4re if the waterway is extensive.Aquatic weed control by manatees may proveexpensive. To breed and rear them, at least atfirst, will be costly, as will transporting thembetween countries.

Experience in Florida has shown that the rangeof their usefulness can only be extended to thesubtropics if warm water refuges are available fortheir use when water temperatures drop below ISoCfor long periods. IS

18. Sguros, P.L. 1966. Research Report and ExtensionProposal Submitted to the Central and SouthernFlorida Flood Control Board on the Use of theFlorida Manatee as an Agent for the Suppressionof Aquatic and Bankweed Growth in EuentWInland Waterways. Department of BiologicalSciences, Florida Atlantic University, Daco Raton,Florida.

Digitized by GoogIe

CHAPTER 3

ANFOR

INTERNATIONAL CENTRE.MANAT'EE RESEARCH

Workshop participants unanimously agreed thatthe establishment of an international centre formanatee research is not only desirable but necessary.Despite its utility and the intriguing research oppor­tunities that the animal affords, no institution inthe world today has the equipment and facilitiesrequired. The participants also firmly believe that itis not only feasible to do research on manatees incaptivity, but because of the manatee's docility andadaptability to confinement, it would be less difficultthan comparable research on seals, dolphins, andother marine mammals already under detailed investi­gation. Participants believe that the Centre should beinternational in concept and operation becausemanatees occur in about forty countries and becauseit has potential utility for weed control throughoutthe tropics. They believe that the advantages ofGuyana over other possible sites for a centre areimpressive and that a manatee research facility issubstantially less likely to succeed if locatedelsewhere.

Participants and sponsors of the workshop recom­mended that the Centre should be an institute ofadvanced research designed to meet the highestinternational standards and enjoy close cooperationwith the scientific community in South America.the Caribbean, and other regions of the tropics (bothwhere manatees now occur and where they couldbe used in future).

Objectives

An international centre for manatee researchshould accept four broad objectives:

18

I. Basic research: To sponsor, promote, andcoordinate activities that will advance knowledgeof manatee biology, with particular emphasison fundamental questions in physiology, emfo­crinology, anatomy, reproductive biology, bio­chemistry, ethology (behaviour), ecology, andrelated disciplines. This will also develop themanatee as a research animal for many basiclife science studies.

2. Aquatic weeds: To examine available infor­mation and assess the effec~yeness of usingmanatees as aquatic weed-control agents inGuyana and to evaluate their potential foruse in other countries.

3. Conservation: To develop ways to producemore manatees, to develop programmes forrepopulating depleted habitats, and to promotethe conservation of manatees wherever theyare now threatened with extinction, and indeedto foster their domestication as with cows.

4. Tropical science: To provide guidance inplanning and in techniques of advanced mamma­lian research. At the same time the closerresearch liaison between universities and researchinstitutions of the developed world and thoseof Guy.ma, the Caribbean, South America, andother tropical regions would promote thegrowth of scientific communities in regionswhere manatees now occur and where theycould be established.

These interests are obviously complementary andinterdependent. The programmes are likely to developat different rates, but for the long-term effectiveness

of the Centre, none should be considered of con­spicuously higher priority than another. In otherwords, the Centre should not become overly concernedwith weed control or with basic research.

TIlls four-pronged approach has the advantagethat should any of its objectives not be achievedpromptly, the Centre would remain viable becauseof achievements in others. For example, it mayprove impracticable to accelerate manatee reproduc­tion, yet the basic physiological, behavioural, andenvironmental information gained in reproductionstudies may still prove critical to manatee conservationand to aquatic weed control.

Because almost nothing is known about thebasic biology of the manatee, initial exploration ofthese subjects must surely advance our knowledge.On the other hand, a realistic appraisal of thepotential of using manatees for general aquatic weedcontrol in the tropics indicates that it could takemany years to establish enough numbers, because ofthe manatee's long gestation period and slow reproduc­tion rate and the substantial time consequentlyneeded to do the basic research for successfulmanatee husbandry. The proposed four-prongedapproach should produce an effective blend of short­term (less than 3 years) and long-term (10 years ormore) benefi ts.

The Centre should be organised and staffed withthe four programme interests explicitly in view.The results derived from anyone endeavour willcontribute to progress in the other three. The impactof multidisciplinary research within the Centre willbe substantial, because of the cumulative effect ofscientists from various disciplines working in associa­tion. Data on nutrition, for instance, are likely tohave a direct bearing on understanding of reproduc­tion, particularly if it turns out that nutrition isin part responsible for poor breeding performance.

Advantages for the Tropics

The participants felt that a manatee researchcentre would have particular advantages for tropicalcountries. Although almost nothing is knowp oftheir thermoregulatory physiology, future utilisationof manatees can only be considered for regions witha year-round tropical climate, because of the manatee'sintolerance to cold water.

Because manatee research promises to yield certainpractical consequences, its research results would bemade available to organisations throughout thetropical world that are concerned with the controlof harmful aquatic weeds and the production of

19

protein, and the centre would cooperate, as ar'prop­riate, with institutions that have similar concerns.

The Centre could have an impact on worldopinion from the outset, and, as research results areobtained, government officials and research workersin tropical countries will, it is hoped, be interestedin applying the Centre's results to their own situationsin, for example:

Countries within the manatee's range of occur­rence that have current or potential weedproblems, such as: Brazil, Colombia, CostaRica, French Guiana, Panama, Peru, Mexico,Surinam, Venezuela, the Cameroons, Ghana,Ivory Coast, Nigeria, Senegal, and Zaire.Other countries outside the range of themanatee's occurrence but within its temperaturerange that have infestations of aquatic weeds.These include Kenya, Sudan, Uganda,Bangladesh, Fiji, India, Indonesia, Malaysia, thePhilippines, Sri Lanka, and countries ofIndochina.

It is anticipated that several of the coU11tries justlisted would from time to time contribute staff tothe Centre's advisory bodies and join in complemen­tary and collaborative research.

The Centre should encourage a scholarship pro­gramme for able younger scientists from less developedcountries to work on the biology of manatees atthe Centre or in their own countries.

At the Centre students from tropical countrieswould gain experience in fields of biological research,without the necessity of going to Europe or NorthAmerica. Furthermore, their training would becomemore relevant and their return home more likelyonce they had conducted biological research of aninternationally acceptable calibre within the sameclimatic zone as their home country.

The existence of a centre of exceilence such asthat proposed could benefit other areas of tropicalresearch: It would provide basic training and researchin such fields as nutrition, husbandry, endocrinology,functional anatomy, mammalogy, aquatic biology,weed control, and water-quality management.

A fairly logical broadening in the scope of researchmight be expected in the future, once the Centrehas proven itself. Foreseeably, the Centre couldevolve into a broadly oriented tropical biologyresearch facility that capitalizes on the scientificallyattractive biota and environment of Guyana.

Organisation

Workshop participants considered several alter­native affUiations and organisational systems. Proposedmodels included national organisations, multigovern­mental schemes, a nonprofit corporation, or auniversity-affiliated unit. The workshop participantswere informed of the example of the InternationalCentre for Insect Physiology and Ecology (ICIPE)recently established in Nairobi, Kenya. This particularautonomous, nongovernmental research institute islocated on the campus of the University of Nairobi,has loose ties to the university, and is committed tothe development of science in Africa. ICIPE wasinitiated by national science councils or scienceacademies;l9 these scientific institutions are represen­ted on the International Advisory Committee toICIPE. The ICIPE research and training collaborationin Africa is guided by the African Committee.

The research at ICIPE is supervised by Directorsof Research selected by the Governing Board fortheir established excellence and internationalreputation, upon the advice of the InternationalCommittee. They are required to make a long-termcommitment to the Centre, demonstrated by theagreement to make two annual visits and to participatein the Annual Directors of Research Conference.The research is done by their students, who asresident scientists rotate in spending a normal post­doctoral term (2 - 3 years) ~t lCIPE. The students'salaries are paid from postdoctoral fellowshipsobtained in their native countries or from projectgrants to ICIPE from the United Nations DevelopmentProgram. African scientists spend resident terms atthe Centre as well often under the guidance of aResearch Director.

The advantage of the ICIPE model is that itdemonstrates how a research station, with partici­pation by highly competent researchers, can beestablished in a less developed country withoutincurring the time-consuming construction of aresearch infrastructure or a full time budget commit­ment. It does not require as much financing as woulda facility with a permanent staff; and it can be moreopen to changes in research priorities because of therotating staff.

The workshop participants finally agreed that themost practicable and suitable mode for the manateeresearch centre was a nongovernmental, autonomous,

19. Of Australia, Czechoslovakia, Denmark, Germany,Hungary, Israel, Japan, Kenya, the Netherlands,Norway, Sweden, Switzerland, Tanzania, UnitedKingdom, United States, and Zambia.

20

internationally supported organisation, one thatreflects the needs of the international communitywithin the context of the laws of the host country.It is suggested that the Government of Guyana shouldaccept the International Centre for Manatee Researchas an institution of higher learning or as a nonprofitinstitution.

A board of trustees should be appointed andgiven responsibility for the general guidance of theCentre. The board of trustees should seek funds andshould be responsible for fiscal policy and foraccounting to donors and funding agencies. It shouldappoint a scientifically qualified person as directorof the Centre for such a period and on such terms asit may determine.

The board might well benefit from participationby two specific consultative and advisory bodies:(1) a host-country advisory council and (2) aninternational advisory committee. The host-countryadvisory council should represent Guyanese interests,such as those of the university and the governmentaldepartments whose work can facilitate the develop­ment of the Centre and whose interests relate to itsprogramme. It would advise the governing board onnational regulations, relationships with neighbouringcountries, and on cooperative programmes betweenthe Centre and other research and teaching institut­ions in the country.

The international advisory committee should becomposed of representatives from international organ­isations and national scientific bodies that havedemonstrated a special interest in the Centre. Itwould advise the governing board on: stimulatinginternational interest in the Centre; the scientificprogramme; membership of the governing board andsenh>r staff of the Centre; and procurement of fundsfor developing the Centre. National research councils,science academies, and other scientific bodies mightbe used to appoint representatives to the inter­national advisory committee.

It was recommended that representatives on thesecommittees be individuals working in fields relatedto the Centre's interests and objectives. The directorwould be an ex officio member of all committeesof the Centre.

Staffing

It is envisioned that the Centre will begin in amodest way, with a small staff of about fivescientists with supporting technicians and adminis­trative staff. As research programmes progress, andas the potential for manatee utilisation becomesclearer, the numbers may ultimately increase to about

25 or 30 professionals by the time the first self­perpetuating manatee "farm" is established (possiblyby 1985).

If the ICIPE model is adopted, the permanentstaff of the manatee centre would be limited tothe director, a financial manager, support-servicepersoMel, and a few permanent researchers. Theresearch, in the main, would be undertaken bygraduate and postdoctoral students under theguidance of directors of research who would berequired to visit the Centre at frequent intervals tosupervise the work. Apart from this, each residentscientist or team would be largely self-directed.

A rotating cadre of young, highly trainedresearchers, ambitious to build a career, is animportant asset. Under this scheme, the Centre isless likely to become scientifically inbred. It should,of course, strive to involve substantial numbers ofLatin American, Caribbean, and West African studentsand research directors.

Guyana as Site for the ('.entre

The participants of the workshop agreed thatGuyana was one of the few regions where sufficientnumbers of manatees are available to provide thenecessary large stock for research and attempts atdomestication.

Trichechus manatus thrives in all the large coastalrivers, namely the Essequibo, the Demerara, Berbice,and Corentyne and in the smaller rivers of theMahaica, Mahaicony, and Abary. It is found primarilyin the lower reaches of all of them. Manatees occurabove the waterfalls in the Berbice and Essequiborivers and their tributaries, but the species has notbeen clearly identified. In the Essequibo it isprobably T. inunguis because this species occurs inthe tributaries of the Amazonian rivers, Branco andNegro, which, during flood periods, become almostcontinuous with the tributaries of the EssequiboRiver.

Guyana has an ideal climate and temperature forrearing manatees. The coastal region is dissected byseveral thousand miles of canals for irrigation, drain­age, and transport, in which water weeds occur (seeFIGURE 8,) and experiments could be conducted.Also, there is not only governmental scientificinterest, but also a substantial public interest inprotecting the animals. Governmental interest hasexpressed itself in a commitment to provide suitablesites and services, and to collaborate with theCentre through the National Science ResearchCouncil, the University of Guyana, and agriculturaland veterinary research Institutions.

21

As a research base, coastal Guyana also providesa pleasant, healthful climate and locale for visitingscientists; it has no serious waterborne human healthhazards, and is easily accessible within a day'sair transportation from Europe or North America.Noteworthy considerations for an internationalcentre, is that Guyana enjoys excellent relationswith countries where manatees occur, in both SouthAmerica and West Africa. The cost of living andanimal maintenance and support services are alsofavourable.

The workshop participants acknowledged certaindifficulties inherent in Guyana. There are thedifficulties ofmaintaining delicate scientific equipmentin a tropical climate, the lack of postgraduate scienceinstruction at the university, and the absence of awell-developed research infrastructure, of specialisedmaintenance services, or experienced persoMel. Theneed to import scientific supplies necessitates long­range plaMing. Certain natural circumstances alsoprovide some obstacles; for example, the turbidity ofthe water which makes observations difficult. Theoccurrence of electric eels, piranha, caimans, etc.,is less important.

With careful plaMing and the cooperation of thegovernment, the disadvantages of Guyana could beovercome. The workshop participants thereforerecommended Guyana as a highly suitable site for anInternational Centre for Manatee Research. Theystressed, however, that the Government of Guyanahas a critical role to play in ensuring the Centre'sviability: for example, by allowing the Centre theprivileges that normally apply to international organ­isations, such as exemption from import regulationsfrom taxes on equipment, supplies, and services.These are considered essential for the efficient,rninimal-cost-operations of internationally fundedresearch investigations.

Facilities

Four facilities are needed to integrate the researchefforts best and to attain the Centre's objectivesmost efficiently:

I. A laboratory and close-confinement facility,where detailed experimental work can bepursued in clear-water tanks

2. Controlled canals where field trials for :tquaticweed control and manatee managementtechniques can be conducted and where semi·domestication would be fostered

3. A body of water, such as a conservancy,where the manatees would exist in a near­natural, though confined, state

4. A "wild area," where manatees under natural,unreltricted conditions can be ltudied andtheir population, it is hoped, increased.

The laboratory facility will be coatly, but essential,for a wide range of experimentalltudiel that requireclOie confinement of the experimental animals. Atfint a few, but later a score or more, animals wouldbe required at anyone time. A high-qualfty, well­equipped laboratory will be a neceuary incentive foraverseu experts; it will have to develop into acentre of excellence.

.........It II important to realile that to develop effective

manatee hUlbandry will take time. Because the

22

approximately I-year geltation period cannot becircumvented, herd production will be Ilow delpitethe pOllibility of running several reproductionexperiments concurrently. The Centre'l phasing mayinvolve an initial period of 1 - 3 years and moreyears of qualitative and quantitative biologicalltudybefore aucceuful rearing in confinement or in amanaged population can be achieved. In practicalterms, it aeenu unlikely that an operational manatee"farm" can be establilhed in Guyana in lell than10 years and that the fint auccellful manatee farmelsewhere might be establilhed 3 - S years later.

CHAPTER 4

SUGGESTIONS FOR THERESEARCH PROGRAMME

The widespread use of manatees to control weedsin waterways is contingent on their being availablein large numben. This, in tum, depends on accum·ulating sufficient knowledge of their physiology,nutrition, reproductive biology, and ethology topermit development of effective husbandry.

Research on manatees will not be easy. Theyweigh up to 500 kg (1,200 lbs) and remain submergedmost of the time. Their reproductive rate is com·paratively slow; few specimens are available; andtheir endangered status dictates that very few besacrificed during experimentation. Furthermore,because the animal's native habitat is ill tropicalcountries, most research must be doneowhere facilitiesand equipment are not readily obtainable and aredifficult to maintain. It will probably have to bedone in a newly established institution, which cir­cumstance has its own inherent problems.

The folowing are long·term research needs:Development of breeding colonies.

Effective handling and management of manateesfor aquatic weed controlArtificially stimulated reproduction and carefulhusbandry of young manateesAdvancement of mammalogy through studyof the basic biology ot' this speciesReplenishment of depleted habitats throughoutthe tropical worldImprovement of protection for the nativemanatee herds now approaching extinction inat least 40 nations (see list, Table I)

CENTRE'S

Because so little is known about manatees,opportunities abound for important research findings.Application of newer techniques already used success­fully with other animals may prOVide speedy resultswith manatees.

Important comparative biological and behaviouralinformation might be gained if the Centre were tomaintain more than one species of manatee.

General Techniques

Methods must be developed for the humaneluandling of manatees, for identifying individualanimal~, for feeding them, for preventing disease.and for protecting them from poachers. vandal~. andaccidental drowning. Much ingenuity will be reqUired.The animal's natural seclusion and limited emergencein turbid or discoloured water also presents a spedalproblem.

Complete autopsies should be conducted on allanimais that die, to learn more about their anatomy.physiology, and disease processes. Tissue and fluidsamples should be collected to provide basic data inhaematology, blood chemistry, endocrinology. micro­biology, pathology, etc. Better methods for thecapture, transport, and physical restrain t of theanimals need to be developed.

Reproduction

Uttle is yet known about the manatee's breedinghabits and reproduction. The gestation period, ageat sexual maturity, length of the reproductive cycle.frequency of reproduction, and life expectancy arc

23

all undetermined. They apparently lack a definedbreeding season, and have a slow reproductive rateA female probably breeds at no less than every 2years - and more likely every 2.5 - 3 years. Manateeshave seldom bred in captivity; hence, one of thefirst research objectives should be to ascertain thenature of the underlying factors - whether nutritional,environmental, behavioural, or endocrinological.

Regardless of the root cause for reproductivefailure under captive conditions, manatees in thewild should be closely observed over protractedperiods of at least 2 years (if necessary by underwatersurveillance) to study their social organisation andsexual behaviour, particularly cyclic sexual behaviour.Special consideration should be given also to themeans of intercommunication (olfactory, auditory,etc~, to the circumstances attending any matingattempts, and to whether the sexes segregate at anytime or season. Knowledge of this kind is basic tothe provision of conditions suitable for reproductionin a confined area.

Without killing the animal, much valuable infor·mation can perhaps be obtained about the lengthof oestrus, time of ovulation, length of gestation,attainment of puberty, etc., by measuring pituitaryand steroidal hormones in the blood. The recentdevelopment of radioimmunoassay, which is capableof detecting minute quantities of these hormones,makes such assessments possible with small samplesof blood.

The interval between individual breeding cyclesis regulated by the time required to wean a calf.Thus, the development of a weaning food couldspeed manatee reproduction in semi-domesticationby allowing the mother to be freed of the calf aftera much shorter interval than is now the case.

Health Care

A veterinary medical programme in a manateeresearch centre is essential to provide health carefor the animals. Besides qualified veterinary personnel,necessary veterinary facilities would include thefollowing: laboratory space for autopsy, clinicalpathology, X ray, anaesthesia and surgery. Quarantinetanks would also be needed to treat sick animals andfor the initial isolation of animals that come to theCentre for research.

Nutrition

Research on manatee nutrition is needed toprovide a better understanding of various aspects

24

of digestive physiology and biochemistry, such as(I) the nutritive value of the natural vegetation;(2) carbohydrate digestion, protein utilization, milkproduction and composition; and, (3) feed intakeof adults and calves on natural and unproved diets.The data collected could lead to an improvement ofthe animal's breeding potential in captivity andpermit early weaning of the calves, thus shorteningthe calving interval and speeding growth of theanimals.

The optimal age for weaning should be the objectof immediate investigation.

Ecology and Behaviour

A complex of experimental studies is prereqUIsiteto a full understanding of the biology of the animaland its behaviour under natural conditions, e.g.,studies on nutritional requirements. energy-transfermechanisms, thermal requi rements, the reproductivecycle, the mediation of the manatee's behaviourthrough its senses - as well as on aquatic-weedproductivity. Varying soil and water conditions in awater body may affect the production, avaiiability.and nutritive value of aquatic weeds and vary theirmanatee-carrying capacity and the manatee's pre­ference for such areas. Factors that can enhance ahabitat to support the largest number of animalsshould be investigated. Most are studies to beconducted primarily in the animals' naturalenvironment.

Basic studies on the relations between manateesand their environment should include:

Chemical, physical, and topographical con­ditions of the water environment in whichmanatees occur. with particular reference tobreeding and calVing localities

Quality of the water in which manatees live,e.g., pH, oxygen content, salinity. temperature.

Food plants, feeding patterns, and environ­mental conditions that contribute to theabundance of the animal in river enVironments.and the carrying capacity of various environ­ments; andPopulation structure, density, and sex ratios ofmanatees in the wild.

An important requisite for ecological andbehavioural studies is to locate, mark. and identifymanatees, since the animals are normally invisible indiscoloured tropical waters. Radio tracking will alsobe important.

Based on obseryations in Florida, the followingaspects of wild manatee behaviour are likely to bemost significant:

Migration and local movements

Daily and seasonal activities of significance tohusbandry and survival

Maintenance behaviour (feed preference andavailability in relation to nutritive requirements)

Social aggregations, mother - offspring inter·

actions from birth to weaning, and copulatorybehaviour

Sensory responses and learning behaviour

Man - manatee relations

Much more needs to be known about the dis­tribution. abundance, social structure, migrations.and population dynamics of existing natural pop­ulations. Such studies may be facilitated throughsophisticated new study techniques developed forobserving wildlife, particularly the marine mammals.Once elucidated, the behaviour patterns of manateesshould provide vital information on their choiceof habitat.

Aquatic Weed-Control Research

Initially, certain basic studies must be made:

Quantitative measurement of the effectivenessof manatees as weed-control agents in differentaquatic enVironments, e.g., quantifying thecomposition and productivity of aquatic weeds,the amount and composition consumed daily,the amount of nutrients returned to thewaterways as faeces, and changes in the plantspecies presen t

25

Parameters for steady-state cropping, andmanatee spacing

Design of kokers (a small floodgate used inGuyana), sluices, culverts, etc., that are safefor manatees and fences that can contain them

Conservation Research

The Centre should produce and collate manateecensus data for all the regions where the animal isfound. It shouid endeavour to alert the forty orso governments in whose territories the animal occursto its importance and its endangered status.

. Some of this educational programme may beaccomplished by encouraging local zoos and botanicalgardens to include manatees in their displays. and hypromoting collaborative manatee research and weed·control experiments in universities and researchorganizations.

The Centre could initiate many collaborativeefforts by providing guidelines for the care andpreservation of manatees and by short-term work·study programmes for nationals of the coun triesinvolved. Communication could be maintained by anewsletter that contains information on the latestfindings from each of the collaborating institutionsand, for trainees, hy periodic return visits to theCentre.

Every effort should be made to enforce existingprotective legislation in each country where manateesexist; this is fundamental. Once manatee breedingand husbandry have been achieved at the Centre,pilot introductions to repopulate depleted herdsshould be conducted.

The immediate goal should be the establishmentof a manatee reserve within Guyana.

APPENDIX A

MANATEE WORKSHOPPARTICIPANTS

W.H.L.. ALLSOPP,

DENNIS H. IRVINE,

DONALD S. FARNER,

NOEL D. VIETMEYER,

Brazil

PAULO DE ALMEIDA MACHADO,

PAULO E. VANZOLINI,

Coflllda

KEITH RONALD,

Colombia

ALONZO RAMOS,

Guyana

JOHN BATES,

G.E. BURNHAM,

LAWRENCEG. CHARLES,

ELSIE CROAL,

ANADA DHARRY,

Associate Director Fisheries, International DevelopmentResearch Centre, Ottawa, Canada, Cochainnan

National Science Research Council, .and Vice-Chancellor.University of Guyana, Georgetown, Guyana, Cochainnan

Chairman, Division of Biological Sciences, NationalAcademy of Sciences, and Department of Zoology,University of Washington, Seattle, Washington, USA,Cochainnan

Professional Associate, National Academy of Sciences,Washington, D.C., USA Staff Study Director

Director-General, Instituto Nacional de Pesquisas Manaus

Director, Zoology Museum, University of Sao Paulo,Sao Paulo

Dean, College of Biological Science, University of Guelph.Guelph. Ontario

Associate Professor. Fish Culture. University of Caldas,Manizales

Senior Agricultural Officer, Bookers Sugar Estates Ltd ..Georgetown

Deputy Director, Museum and Zoo. Georgetown

Chief Engineer. Hydraulics. Drainage and Irrigation andSea Defence, Ministry of Works, Georgetown

Curator, Botanical Gardens, Georgetown

Specialist Engineer. Drainage and Irrigation. Ministry ofWorks and Communications. Georgetown

26

HENRY DOLPHIN,

ALFRED V. DOWNER,

PETER FERNANDES,

ALLAN FOX,

ULRIC GIBSON,

DATAKARAN' JEETLALL,

FRANK MONGUL,

G. NURSE,

OMAWALE,

BJLB. PERSAUD,

POPE DEO PERSAUD,

JAMES RICHARDSON,

J.B. RITSON,

NERLE ROBERTSON,

ERNEST SANFORD,

BALRAM SINGH,

BOB VEERASAMMY,

HOLMAN E. WILLIAMS,

Unit~d Klntdom

E.C. AMOROSO,

G. COLIN L. BERTRAM,

SIR ALAN S. PARKES,·

Queenstown, Georgetown

Principal Agricultural Officer (Crop Science) CentralAgricultural Station, Mon RepOl, E.C.D.

Principal Agricultural Officer, (Vet. and Animal Science)Ministry of National Development and Agriculture,Georgetown

Veterinary Officer, Ministry of National Development andAgriculture, Georgetown

General Manager, Guyana Water Authorit)l, Georgetown

Bushlot, West Cout, Berbice

Principal Veterinary Officer, Ministry of Health,Georgetown

Uveltock Officer Ministry of National Development andAgriculture, GeorgetownDean, Faculty of Natural Sciences, University of Guyana,Georgetown

Senior Lecturer, Department of Biology, University ofGuyana, Georgetown

Uvestock Officer, Ministry of National Development andAgriculture, Georgetown

Deputy Chief Engineer, Georgetown Sewerage and WaterCommiaaioners, Georgetown

Head, World Bank Uvestock Project, Georgetown

Agricultural Officer, Central Agricultural Station, MonRepOl

Veterinary Officer, Central Agricultural Station, Mon Repos

Taxidermist, Guyana Museum, Georgetown

Free Lance Biologist, Georgetown

Head, Department of Uvestock Science, University ofthe Weat Indiel, St. Agustine

Agricultural Research Council, Institute of AnimalPhysiology, Brabaham, Cambridge

St. John's CoUege, Cambridge

Medical Research Council and Chairman, Galton Foundation,London (Contributor)

1

*Contributed PIPers but not prelellt for work­mop dilc:uuiolll.

27

United States of America

RUTH ADAMS,

CLARENCE B. AMMERMAN,

CARLTONG. CHAPMAN,

DANIEL S. HARTMAN,

ROLAND K.. MEYER,

CARLETONG. RAY,

VICTOR B. SCHEFFER,

Venezuela

FRANZ WEIBEZAHN,·

International OrganisDtions

BARRY NESTEL,

Observers

SANDY HUSAR,

DIANA H. MAGOR,

CLYDE SANGER,

DAVID SPURGEON,

Member, Board of Governors, International Centre forInsect Physiology and Ecology, Nairobi, K.enya andExecutive Secretary, American Civil Uberties Union,illinois

Department of Animal Science, University of Florida,Gainesville, Florida

Miami Seaquarium, Miami, Florida

West Forks, Maille

Senior Scientist, Wisconsin Regional Primate ResearchCenter, University of Wisconsin, Madison, Wisconsin

Department of Pathobiology, Johns Hopkins University,Baltimore, Maryland

Chairman, Marine Mammals Commission, Washington, D.C.

Director, Biology School, University of Central VenezuelaCaracas

Associate Director (Animal Science), International Develop­ment Research Center, Bogota, D.E., Colombia

National Musuem of Natural History, Smithsonian Institute,Washington, D.C. USA

Leticia, Colombia

Director of Office of Public Information and EditorGeneral of Publications, International DevelopmentResearch Center, Ottawa, Canada

Associate Director of Information Sciences, InternationalDevelopment Research Center, Ottawa, Canada

28

APPENDIX B

ACKNOWLEDGMENTS

The generosity of the Guyana Sugar ProducersAssociation in providing an aeroplane tlight toBerbice and a boat trip to the East DemeraraWater Conservancy, and of the Ministry of Worksand Communications in organising a demonstrationof manatees feeding on aquatic weeds in a canaland a boat trip to a natural manatee habitat in theAbary River is gratefully acknowledged.

The workshop participants express their appre­ciation to Mrs. Mona Irvine, Conference Officer,for organising the workshop details; and to JoanGilkes, Mary Jane Koob. Jeanne Smith, and PearlVigilance for secretarial support, and to Hugh W.L.

29

Payne, Government Archivist. for providing themwith a detailed history of manatees and their usein Guyana.

Funds for the workshop were provided by

National Science Research Council of Guyana

International Development Research Centre

National Science Foundation (USA)

Office of Science and Technology, Agency forInternational Development (USA)

International Union for the Conservation ofNature (Switzerland)

GUYANA

v

FIGURE 8 MaiMteeI .... found throughout the coutal ruch. of the riven in Guy.na. Wh.r. noted on the map, concent,.tiol1l_re __011 by lUff of the Works .nd Communlcotions Ministry during the month. prior to .... workshop. During tholoot __ m8ne_ h....__ doliberet.ly ••n oqu.tic _-control _ ... to the Th_ Fri.ndI Conel. W...·Georgie

DiI1ributory. Gordon of Eclon cONII•• Cr.ig Diltributory. Tor.,i Co..... end conoIo in the Block Bush fl'oldor. _.irie .nd~t Dome,.,. _tor .-..rYM1C'-o .re m.._ .._with • combinod .... of more ....n 1.000 km2 .nd .n ..,.... depth01 3 m.~ could pr_ the m contre -'oil ..... for t"ing mo....-.....-v..ion proct_. Som. of ....

riwn Ih_n could be uood for studying ......t .........,iour in the wild. 1_on. mop ouppliod by tho Worll• .,d CommunlcotionsMinistry. Guvonel

(1

AnANTIC OCEAN

GUYANA

~"

APPENDIX C

GUYANA

Guyana (fonnedy British Guiana) lies along thenortheast shoulder of South America betweenVenezuela and Surinam and borders Brazil to thesouth (See map, FIGURE 8). It is the only English·speaking country on the continent. Guyana has closeties with the Caribbean community, particularly theEnglish-speaking territories with which it sharesmembership in the British Commonwealth. MOlt ofits 215,000 lan2 (roughly the size of the UnitedKingdom) is tropical rain forests.

Three distinct geographical areas in Guyana arethe coastal, the savannah, and the mountain regions.

The coastal region is about 440 Ian long andvaries in width from 16 to 65 Ian - traversing thecountry from the northwest to the Corentyne River.The region includes most of the population and isintensively cultivated, despite the fact that it is onlyabout 4 percent of the total area.

The country is broken up by rivers and streams.The main rivers - the Essequibo, Demerara, and,Berbice - are navigable for approximately 80, 105,and 160 Ian respectively.

Guyana's multiethnir. population reflects itsimmigrant history. In July 1972 the population wassaid to be 714,233. Georgetown, the capital, and itsenvirons has a population of 167,078.

The climate is equable throughout the year; meantemperature is about 27 C, with an average rainfallof 200 em in the coastal belt, mostly confined totwo rainy seasons, November - January and June·July.

In the high interior savannah, the climate iscooler because of higher elevation and lower humidityand rainfall. In the mountainous forested areas, theclimate is hot and rainfall is high. Unlike some nearby

31

Caribbean countries, Guyana is not afflicted withhurricanes.

Before 1814 the English, Dutch, and Frenchfought for outright possession of Guyana. In thatyear Essequibo, Demerara, and Berbice were cededto Britain; in 1831, these three colonies merged tobecome British Guiana.

Slaves from West Africa undergirded the plantationeconomy of the territory. After the abolition ofslavery they left the plantations, and immigrantswere brought from Portugal. China, and fmally ingreat numbers from India to provide the necessarylabour.

The population today includes people of African.East Indian, Chinese, Portuguese. European. andAmerindian origin.

Guyana achieved independence on May 26. 1966,and became a cooperative republic on February 23,1970.

Guyana has a high literacy rate, considered to beabout 85 percent. The University of Guyana,established in 1963, has five Faculties: Arts, NaturalScience, Social Science, Education, and Technology.The first three offer first degree as well as diplomacourses. Education offers a postgraduate in-servicediploma, while Technology offers a general technicaldiploma, as well as higher diplomas in engineeringand architecture.

Since 1969 the university has occupied itspermanent site at Turkeyen (FIGURES 8, 14), some4 . 5 miles from the centre of Georgetown. The140-acre site was a gift of the Booker Group ofCompanies; the original nine buildings, erected at acost of nearly GS5.0 million, were made possible

FIGURE 14 Pen of the modern cempul of the University of Guyen.. (Univers.ity of Guyenel

by capital grants from the governments of Britain,Canada, and Guyana.

Roughly 40 percent of the original capital grantwas for the needs of the Faculties of Natural Scienceand Technology; subsequent grants-in-aid from theoriginal donor countries have succeeded in improvingfacilities to the point where scientific research of ahigh quality can be pursued. Several of the staffare engaged in research relevant to the problems ofGuyana.

Currently, the only graduate studies programmeis in the department of history, but graduate studiesin all departments are to be phased in over the nextfew years. There is as yet no faculty of agriculture,altllOUgh it is planned, and no medical faculty.However, the university offers a certificate coursein medical technology, a diploma in pharmacy, anda diploma course for the training of medical auxiliaries.A centre for paramedical studies is to be built shortly.

The university library has at present about 80,000volumes of which about 7,000 are in the sciences.It receives 122 scientific periodicals. It is hoped toexpand the physical facilities of the library withinthe next 5 - 10 years, and to increase its holdings tosome 300,000 volumes, with greater emphasis onscience.

Guyana is a member of the United Nations andseveral of its specialized agencies, the General Agree­ment on Tariffs and Trade (GATT), and theCommonwealth of Nations. lt also participates inthe Organization of American States (OAS) as apermanent observer.

Since 1969 Guyana has increasingly identifieditself with the nonaligned nations of the world, andis now expanding its diplomatic contacts, especially

32

with the African countries of Ethiopia, Guinea,Kenya, Nigeria, Tanzania, Uganda, and Zambia.

Guyana's economy is basically agrarian and,historically, has depended on sugar, which in 1970accounted for, 29 percent of' the country's exports.Rice, 6 percent of 1970 exports, has beco!lle amajor crop in recent years. Bauxite mining andaluminium production are Guyana's principal indus­tries, together accounting for 52 percent of 1970exports.

The Agriculture Division is carrying on researchto facilitate opening up the interior in line with thegovernment's 1966 - 1972 Development Programme.In addition to its central research laboratories, whichhave a library, the division has livestock stations atEbini and Rupununi and an agricultural station inthe Northwest.

The Ebini station is a modern, well equippedlivestock nutrition research facility. A veterinarydiagnostic laboratory is under construction in theEast Demerara Area close to the Mon ReposAgricultural Research Station.

Most of the coastal area is below sea level andis protected from the Atlantic Ocean on the northby a system of dikes and sea defences, and in thehigher land to the south by earthworks enclosinglarge, shallow catchment areas called conservancies.The conservancies are hugh man-made lakes and,when full, cover some 1050 sq km of water, averaging3 m in depth.

The drainage and irrigation system of Guyana'scoastal plain is extensive and costly. Many areashave had to be abandoned, and new areas haveproved expensive to open because of the poordrainage of the plain. Gravity drainage is possible

DILllzed bvGooglc

only at low tides and is supplemented by largepumping stations that push the unwjmted water,including used irrigation water, into the sea. All newcoastal settlement projects require extensive drainagecontrol before they are suitable for agricultural use.

Sugar estates in Guyana have two extensive andseparate canal systems: the low·level "sidelines"

APPENDIX D

SELECTED READINGSMANATEES

(with their field drains) for drainage and the high.level"middle-walks" and "cross-canals", about 2 m higher,for transport and irrigation. For each 250 ha ofcultivated cane there are an estimated 26 km ofhigh.level canals, 6 - 8 km of low-level canals, and72 km of small field drains. In both high- and low­level canals, control of aquatic weeds has alwaysbeen difficult.

Allsopp, W.H.L.

Allsopp, W.H.L.

Bertram, C.K., and G.C.L. Bertram.

Bertram, G.C.L., and C.K.R. Bertram.

Dampier, William.

Batt,R.T.

Jones, J.K., Jr., and R.R. Johnson.

Esquemeling, A.O.

Hartman, D.S.

1960

1969

1968

1973

1729

1934

1967

1678

1971

The manatee: ecology and use for weed control.Nature 188:762-

Aquatic weeds control by manatees: its prospects andproblems. In Man-made Lakes, The Accra Symposiump. 344. Ghana University Press, Accra.

Bionomics of dugongs and manatees. Nature 218 :423-6.

The modem Sirenia: their distribution and status.Biological Journal of the Linnean Society 5(4):297-338.

A New Voyage Round the World. 7th ed. Vol. I,pp. 32 - 35. (Modem reprint: New York: DoverPublications, n.d.)

The American Museum Congo Expedition manatee andother recent manatees. Bulletin of the AmericanMuseum of Natural History 66: 533 - 66.

Sirenians. In Recent Mammals of the World: A Synopsisof Families, eds., S. Anderson and J.K. Jones, Jr.Ne\4 York: Ronald Press. 453 p.

The Buccaneers of America. Baltimore, Maryland:Penguin Books. p. 211. (1969 reprint.)

Behaviour and ecology of the Florida manatee atCrystal River, Citrus County. Ph.D thesis, CornellUniversity, Ithaca, New York. 285 p. Available fromUniversity Microfilms Ann Arbor, Michigan.

33

a:= jL-Hatl, R.T.

Jones, J.K., Jr., andR.R. Johnson.

Kaiser, H.

Mohr, E.

AQUATIC WEEDS

Holm, L.G., L.W. Weldon, andR.D. Blackburn.

lowe-McConnell, R.H., ed.

Sculthorpe, C.D.

Some Prospects for Aquatic WeedManagement in Guyana.

GUYANA

1934 The American Museum Congo Expidition Manatee andOther Recent Manatees. 66:533-66.

1967 Sirenians. In Recent Mammals of the World: A Synopsisof Families, eds., S. Anderson and J.K. Jones. Jr.New York: Ronald Pre~s. 453 p.

1973 Morphology of the Sirenia. Basle. Switzerland: KargerPublisher.

1957 Sirenen oder Seekuhe; Leipzig: Die Neue Brehm-Bucherei.61 p. (in German).

1969 Aquatic weeds. Science 166: 699-709.

1966 Man-made Lakes. London: Institute of Biology,Academic Press. 218 p.

1967 The Biology of Aquatic Vascular Plants. London:Edward Arnold, Ltd. 610 p.

1973 Georgetown: National Science Research Council ofGuyana 39 p. Available from NSRC, Guyana.

American University.

King, K.F.S.

Smith, R.R.

Swan, Michael.

1969

1968

1962

1957

Area Handbook for Guyana. Washingtoll. D.C.: U.S.Government Printing Office.

Land and People in Guyana. Oxford, England:Commonwealth Forestry Institute, University of Oxford.150 p. (cost 12s 6d).

British Guiana. London, Oxford University Press.

British Guiana: Land of Six Peoples. London: HerMajesty's Stationery Office.

34