conference “blue growth in the mediterranean : perspectives of spain

Researching in sustainability of marine living resources: the impact

of Mediterranean variability on bluefin tuna spawning grounds and

population dynamics

Francisco Alemany IEO Senior Scientist

Conference “Blue Growth in the Mediterranean: Perspectives of Spain.Palma de Mallorca, 2-3 Mayo 2013

Workshop 2: MARINE RESEARCH: CONTRIBUTION TO SCIENCE, INDUSTRY AND NEEDS OF SOCIETY.

TALK STRUCTURE

Marine exploited populations biomass fluctuations:some evidences, causes and underlying mechanisms.

Do fisheries management systems account for environmental influence on exploited populations dynamics? “Traditional” vs. Ecosystem Based Fisheries Management.

Developing tools for incorporating ecological knowledge into Fisheries Management systems: the case of Balearic islands Bluefin tuna spawning grounds.

Marine exploited populations biomass fluctuations: some evidences, causes and underlying mechanisms.

•It is a well know fact that the abundance and biomass of some marine organisms can show important variations over time. Paleontological studies allow to state that such fluctuations can be attributable to natural causes

•In addition, data from fisheries statistics gathered during the last century show that these fluctuations can be of high magnitude and synchronic at global scale, which suggest that some of them can be driven by global climatic cycles, derived in some cases from astronomic cycles



Late

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Bottom trawl surveys, Pavlov Bay, AK(from Botsford et al. 1997)

•These variations do not occur only in short living small pelagics stocks, but have been observed also in demersal fisheries, as those of gadoids in the north Atlantic.


Summing up, in addition to the variations in exploited stocks biomass caused directly by fishing pressure, the environmental scenario determine also, and in some cases to a great extent, the dynamics of such exploited stocks.

But, what are the underlying mechanisms, inducing these fluctuations?


At the begining of 20th century Hjort (1914-1926)

hypothesized that the larval phase of fishes (most of marine

organisms have a dispersive planktonic larval phase)

constitute a critical period in which recruitment sthrength is

determined. Many derived hypothesis have been proposed to

explain the processes controling larval mortality (“Match-

Mismatch” Cushing (1975); “Stable Ocean” Lasker (1981);

“Recruitment Windows” Cury and Roy (1989);“Member-

vagrant” Sinclair (1988); “Ocean triads” Bakun (1998)…) and

some of them have been demonstrated.


Recruitment processes

Spawning stock

Recruited juveniles JuvenilesLarval phases

Abiotic

Anthropic impacts

Environmental factors

Climate

Biotic Abiotic


In general, it can be stated that variations in the environmental scenarios induce changes in the daily larval mortality rates. The accumulative effect of such variations can result in large interannual differences in the number of individuals that survive to become juveniles. This, besides processes that affect juveniles mortality rates, which can depend also on environmental factors, and hence the number of recruits incorporated annually to the exploited phase of the populations, determine to a large extent (besides the fishing mortality) the dynamics of the stocks.


An important question arises from the previous statements: How –in the case they really do- the current fisheries evaluation and management systems take into account this environmental influence on recruitment?

“Knowledge on stock recruitment is the backbone of fisheries research and the basic prerequisite for sustaining the fishing industry...” (Otto Kinne)

“We know now that the only way in which the problem will be solved is the examination of the dynamics of life in the larval stages. The research is needed and, without it, management will remain self defeating. Paymasters will learn this, if slowly, so slowly.” (David Cushing)


FMCRBBB 12

Recruitment

Growth

Inmigration

Natural mortality

Migration

Fishing mortality

Exploited stock biomass

Considering I=E (Russell, 1931)

Do fisheries management systems account for environmental influence on exploited populationsdynamics? “Traditional” vs. Ecosystem Based Fisheries Management.

Most of fisheries management carried out during the second half of 20th century derives from the basic Russell’s equation. Environmental factors are not explicitelly considered, but are implicit in most of the terms. However, most of attention was focused on growth and fishing mortality, whereas natural mortality and recruitment parameters were usually considered merely as constants derived from empirically estimated relationships, as stock-recruitment models, usually not very accurate….


Considering globally the state of living marine resources, with landings limited around values of 85 million tons despite the increase of fishing effort; the higher proportion of small sized and low commercial value fishes; the very high percentage of overexploited stocks and the habitat degradation, it must be recognized that this traditional fishery management approach have failed….

Lack of well designed and operative management systems in some areas

Do not take into account the scientific reccomendations due to political reasons

Errors in the determination of parameters required by the models (biassed landing statistics, growth parameters…)

Uncompliance of protective measures…


There are many causes behind this failure…..


…but it must be recognized that this have been a reductionist approach, since most of fisheries management carried out up to now have been based in monospecific models that do not account explicitly the environmental influence on recruitment processes, the state of the habitats or the complex biological interactions among species (trophic webs…)


In order to overcome the obvious weakness of the current systems, a new paradigm emerged during the last decades of 20th century, the Ecosystem Based Approach, and after the Ecosystem Based Fisheries Management which, inversely to traditional approach, is: • geographically specified• adaptive• takes account of ecosystemknowledge & uncertainties• considers multiple externalinfluences• strives to balance diversesocial objectives (tradeoffs)


•Focus on Managing Ecosystem Parts

•Individual species

•Small spatial scale

•Short-term perspective

•Humans: independent of ecosystems

•Management divorced fromresearch

•Managing commodities

This new paradigm implies to passfrom to

•Focus on Ecosystem relationships, processes, and tradeoffs•Ecosystems

•Multiple scales

•Long-term perspective

•Humans: integral part of ecosystems

•Adaptive management

•Sustaining production potentialfor goods and services

Regarding EU Fishing Policy, this approach was already introduced in the 2001 Green Document, suggesting to integrate the environmental dimension in fisheries management, but recognizing the insufficiency of current scientific knowledge to do it. Thus, one of the objectives proposed for the 2002 CFP reform was “to improve the quality and quantity of relevant data to sustain the management decissions and to promote multidisciplinary scientific research, which will allow to obtain better scientific information and assessment on fisheries, the related ecosystems and the relevant environmental factors”More recent EU Comission communications establish that “The scientific assessment should cover all the relevant factors, noteworthy the interactions among fisheries, resources and ecosystems, considering biological, technical, environmental and socioeconomical factors”.



Finally, what was finally agreed and included in the 2002 CFP reform was:“The Common Fisheries Policy shall ensure exploitation of living aquatic resources that provides sustainable economic, environmental and social conditions. For this purpose, the Community shall apply the precautionary approach in taking measures designed to protect and conserve living aquatic resources, to provide for their sustainable exploitation and to minimise the impact of fishing activities on marine eco-systems. It shall aim at a progressive implementation of an eco-system based approach to fisheries management......”

This is at best a vague guiding principle, rendered optional by the wording “shall aim” and gradual by the phrase “progressive implementation...”


Maybe because of that the CFP continued failing in achieving its objectives, and a new reform is being implemented… Undoubtely, environmental issues are nowadays an important element not only within the framework of CFP, but also in the broader management scheme that represent the Marine Strategy Framework Directive.This represent a clear advance in relation to the previous approaches, but still a lot of relevant scientific knowledge on marine ecosystems and the ecology of exploited species is not fully considered for management purposes.In part this divorce between basic ecological research and management is attributable to the fact that most of the ecological knowledge remain at an academic level, because of the lack of tools allowing the translation of basic knowledge into practical information directly useful for adopting management decissions.


Within this context, the Spanish Institute of Oceanography (IEO) initiated in 2001 a project dealing with Bluefin larval ecology, whose goal was to provide new scientific knowledge useful for improving the management of this emblematic species, aiming at the recovery and sustainability of this valuable resource …. As a first reference, in this species environmentally driven changes in populations abundance have been also registered…colapse induced by the “small ice age”?


First phase, the TUNIBAL program…“Influence of environmental factors on reproductive strategy and survival of bluefin tuna and related species off Balearic sea”

Immediate objectives:To determine the influence of environmental

conditions on the location of the spawning zonesTo characterize the environmental scenarios favouring

tuna larvae survival, defining “optimal environmental windows”

To evaluate the relationship between regional hydrodynamis scenarios, conditioned by climatic factors, and the location and extent of spawling sites and the areas of enhanced larval survival

Tunibal surveys

• TUNIBAL 02• TUNIBAL 03

• TUNIBAL 01

• TUNIBAL 05

• TUNIBAL 04

• 15 June-10 July

• 27June-23 July

• 18June-10 July

• 4 July-30 July

• 5th June-30 June

• Vizconde de Eza

• TUNIBAL 06• TUNIBAL 07• TUNIBAL 08

• 17 June-14 July• 13-20 August• 29 July-11 August

• Vizconde de Eza

• Cornide de Saavedra

•Odón de Buen•Odón de Buen



•Odón de Buen

• 6-16 August• TUNIBAL 09 •Odón de Buen


LARGE TUNIBAL SURVEYS SAMPLING METHODOLOGY•VERTICAL CALVET TOWS: MICROZOOPLANKTON SAMPLING•OBLIQUE BONGO 60 200 AND 333 MICRON MESH TOWS: QUANTITATIVE MESO AND ICHTHYOPLANKTON SAMPLING•SUBSURFACE HORIZONTAL BONGO 90 500 AND 2000 MICRONS MESH TOWS: TUNA LARVAE SAMPLING FOR GROWTH AND CONDITION ANALYSIS

ROSSETTE EQUIPPED WITH NISKIN BOTTLES AND CTD FOR HYDROGRAPHIC CHARACTERIZATION: NUTRIENTS, CHLOROPHYLLS, SALINITY, TEMPERATURE, FLUORESCENCE, OXIGEN AND TURBIDITY

ON BOARD SORTING, TAXONOMIC IDENTIFICATION, MEASUREMENT AND PRESERVATION OF TUNA LARVAE IN LIQUID N2 FOR GROWTH AND CONDITION (DNA/RNA) ANALYSIS


MINITUNIBAL SURVEYS 2006-2009SMALLER VESSEL: ONLY DAYTIME SAMPLING AROUND MALLORCA ISLAND

FIRST TRIALS OF VERTICALLY STRUCTURED SAMPLING (2009 SURVEY): MULTINET-MIDI 333 MICRONS, 5 DEPTH RANGES

NEW SAMPLING METHODOLOGIES: OBLIQUE SYNOPTIC TOWS WITH BONGO 20 100 AND 250 MICRONS MESHES AND BONGO 90 500 MICRONS MESHES FROM SURFACE TO THE END OF THE THERMOCLINE.ONBOARD SORTING AND IDENTIFICATION OF SOME LARVAE FOR ISOTOPIC AND INMUNOCITOCHEMICAL STUDIES



These surveys allowed, for example ….

to characterize the environmental scenario where tuna larvae inhabit

to determine the distribution and estructure of tuna larval populations

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to get information on larval growth and condition in relation to environmental factors

, confirming that the Balearic Sea is an important spawning area not only for bluefin tuna, but for the rest of large pelagics inhabiting the Mediterranean sea



…and that the bluefin spawning locations are linked to the inflow of surface Atlantic waters, which present an important interannual variability. Part of this variability is driven by climatic oscillations occouring in North Atlantic….


The huge amount of information gathered within the framework of these projects permitted to advance in the modeling of tuna spawning habitat and larval survival…

Quantifying the influence of environmental factors on larval distribution,


Predicting spawning locations…


Developing Individual based models…

),()(),( , TLRLAlightBLIdtdL

prey

..which show that growth and survival of late larve depends on piscivory, and then spatial overlapping among larvae of different sizes, driven by hydrodynamic scenarios, can play a major role in tuna recruitment process


The next step is to generate information directly applicable to fisheries management, and we are doing it within the framework of two ongoing projects. BLUEFIN: Development of operational models for real time prediction of bluefin spawning locations. Carried out thanks to an agreement between IEO and SOCIB, and to the collaboration of Balfegó Group.ATAME: Determination of larvax index as fishery independent spawning stock biomass evaluation. Spanish National Research Plan project

New research surveys, in which sampling was optimized thanks to facilities provided by SOCIB, as lagrangian satellite tracked buoys, stratified sampling devices, satellite imagery and hydrodynamic models, is being carried out.



All these surveys have been succesful, since high density larval patches have been located and intensively sampled, and the whole Balearic bluefin spawning area have been sampled quantitatively, providing unvaluable information for models improvement and reliable larval index estimation.


In paralel , experiments under controlled conditions have been carried out in the IEO experimental plant of Mazarrón

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The available information on tuna larval ecology in the Balearic islands spawning area constitute probably one of the best data sets existing in the world on this matter.

It has allowed to work in close and fruitful collaboration with the NOAA research teams carrying out similar studies in the Gulf of Mexico, the spawning area of Atlantic Bluefin western stock, taking advantage of synergies and the comparative approach.

It means that the concerns about the lack of scientific knowledge to apply a real ecosystem based approach that consider explicitelly the environmental effects on living resources can be, at least in some cases, overcome through well coordinated research, whenever a political will for maintaining research funds be maintained

SOCIB FACILITIESREMOTE SENSING HYDRODYNAMIC MODELS (Backtracking)

BIBLIOGRAPHY;REARING EXPERIMENTS

STATISTICALANALYSIS

OPERATIVE MODEL OF POTENTIAL SPAWNING AREAS BASED ON RS/HM

NRT PRODUCTS

SHORT TERM PREDICTIONS OF PROB. SPAWNING SITES

IBM TOOL FOR ANALYZING PROCESSES AFFECTING LARVAL SURVIVAL

IBMCOUPLED TO ROMS

GLOBAL MODEL FOR LARVAL SURVIVAL PROBABILITIES AT POTENTIAL SPAWNING SITES

NRT SPAWNING STOCKINFORMATION (TAGS, FLEET, AERIAL SURVEYS)

SHORT TERM RECRUITMENT STRENGTH FORECAST

VALIDATION EXPERIMENT

S

VALIDATION &

MONITORING

LARVAL INDEX

SURVEYS

HISTORICAL TUNIBAL DB

PATCHES/FRONTS SURVEYS PRELIMINARYCHARACTERIZATIONSPAWNING AREAS

BLUEFININFORMATIONSYSTEM

BLUEFINDATABASE

STATISTICAL ANALYSIS

DEFINITIVECHARACTERIZATION POTENTIAL SPAWNING AREAS

CLIMATC MODELS

LONG TERM RECRUITMENT STRENGTH FORECAST


SUMMING UP, BECAUSE OF THE COMPLEXITY OF ECOLOGICAL INTERACTIONS HUGE RESEARCH EFFORTS ARE REQUIRED FOR DEEPENING IN THE UNDERSTANDING OF RECRUITMENT PROCESES.

HOWEVER, SINCE THIS KNOWLEDGE IS CRUCIAL FOR THE PROPER DESIGN OF ECOSYSTEM BASED FISHERIES MANAGEMENT SYSTEMS, ALL THE STAKEHOLDERS (FISHERIES SCIENTISTS, FISHING SECTOR, SCIENCE FUNDING AGENCIES, NATIONAL AND INTERNATIONAL FISHING ADMINISTRATIONS) SHOULD DO THEIR BEST TO GENERATE AND INCORPORATE TO MANAGEMENT DECISSIONS RELEVANT KNOWLEDGE ON ENVIRONMENTAL INFLUENCE ON LIVING RESOURCES DYNAMICS

conference “blue growth in the mediterranean : perspectives of spain

Documents

and underlying mechanisms

industry and needs of

marine research

perspectives of spain

in addition

gestin de pesquerias

dichos sistemas de gestin

enfoque ecosistmico