the use of fads in tuna fisheries · fish). 12/02/2014 use of fads in tuna fisheries 16. tendency...

12/02/2014 Use of FADs in Tuna Fisheries 1

THE USE OF FADS IN TUNAFISHERIES

Gerald P. Scott and Jon Lopez

Requested by the European Parliament'sCommittee on Fisheries

12/02/2014 2

AIM

• Summarize information on influence of FADs onthe ability of a fishing vessel to catch fish:– Based on tuna RFMO data bases,– Extent to which FAD use in tropical tuna fisheries

continues to expand,– Effect of FAD use on targeted tunas and other

accompanying species,– Recommendations

Use of FADs in Tuna Fisheries

Background• Floating objects have been used for centuries to enhance fishers’ capacity to

catch fish.• Over the past half century, fishers have intentionally placed or modified floating

objects to attract fish with increasing frequency.• FADs now support thousands of fishing vessels all over the world for both

industrial and artisanal fleets.• FADs are anchored or drifting and attract tuna and other fish, making it easier to

find and catch them, increasing fishers’ capacity to catch fish.• Since the 1990s purse seine FAD fishing for tropical tunas has rapidly expanded.• Purse seine fishing in general, and especially in FAD fishing, has experienced a

large number of innovations that have made fishing more effective over time.• While FADs attract species of interest to the tuna fleets, they also draw in non-

targeted marine life, such as sharks and other bony fish.• Developing methods to mitigate the impact of FAD fishing on non-targeted, by-

catch, is an active area of research.

12/02/2014 PowerPoint Presentation (edit title in master) 3Use of FADs in Tuna Fisheries

A depiction of types of FADs

• aFADs are mainly placed in coastal zones and frequently used to provideenhanced opportunity for artisanal and semi-industrial fishers.

• dFADs are mainly placed off shore and used by industrial fleets targetingtuna

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aFAD fishing distribution around the globe and examplesof recent designs

• Modern aFADs, with a raft typically made from steel, aluminium and fiberglass, may beanchored in waters up to 2,500 m deep and be equipped with radar reflectors andsolar-powered lights.

• Usually fished using several techniques, such as trolling, pole and line fishing, verticallong-lining, drop-stone hand lining, but rarely by purse-seining.


dFAD fishing distribution around the globe


Recent dFAD design examples12/02/2014 7Use of FADs in Tuna Fisheries

Tropical tunas


Likely Methods by which FAD Fishing hasincreased a Vessel’s Ability to Catch Fish

• “Effort creep” through 23 technological elements contribute to gains inpurse seine fishing efficiency.

• Use of FADs and associated factors (support vessels, technologicalimprovement of FADs, and technological improvement in buoysattached to FADs) have had Major Impact and resulted in SteepIncrease in vessels’ ability to catch fish.

• Tracking buoys are likely the most significant technologicaldevelopment that has occurred within the last 20-30 years for increasingthe efficiency of dFAD tuna fishing.

• Technological innovation operates at the individual vessel level toincrease fleet capacity, undermining attempts to manage capacitythrough vessel numbers.

• Addition of vessels to the fleet also increases capacity and should notbe overlooked as a source of increasing fishing pressure.



The evolution of tracking buoy technologies are likely the mostsignificant technological development that has occurred withinthe last 20-30 years for increasing the efficiency of dFAD tunafishing.

Indian Ocean time-line

Catch Indicators Recorded in tRFMO Data Bases

• Catches of tropical tunas across the world’s oceans havegrown to ~4.5 million tons

• Of this, 60% was recorded by purse seine, and nearly 65% ofpurse seine catch was made by fishing on floating objects.

• Most of the growth in tropical purse seine catch is due toincreasing skipjack catch, which was at 2.8 million t per yearin 2012.

• Since the early 1990s, purse seine catches of tropical tunasincreased by nearly 60% which reflected an increase of about33% in free school catches but nearly an 82% increase incatches made on floating objects

• Global patterns largely reflect the pattern in the WesternCentral Pacific and can mask other regional patterns.

12/02/2014 PowerPoint Presentation (edit title in master) 12

JLopez3

JLopez3 May be say that usually, global patterns are masked by the WCPC catches and that more detailed information is needed to better understandoceano-specific trends.Jon Lopez; 30/01/2014

Global growth in catches of tropical tunasFluctuation in catches in the past decade for Bigeye and Yellowfin, which are taken in longline,purse seine and pole and line fisheries are evident, while continued global growth in skipjackcatches, which are made primarily by purse seine and pole and line fisheries is has occurred.This growth has largely resulted from growth in purse seine FAD effort.


Global Growth in Purse Seine CatchThe level of change between 1990 and now varies with species and type of purse seine fishingmode. Considering only catch, these changes over time could have resulted from increased effort,increased stock abundance, and/or increased capacity to catch fish. Of these, increased abundanceseems least likely.


Tendency in catch proportion for purse seineSince the early 1990s, the proportional representation of purse seine tropical tuna catch relative toglobal catch across all gears has also increased (at about a 1% per year), but the proportionalrepresentation of object-oriented catch of tropical tunas shows a more variable tendency with the mostrecent proportions generally higher than those of the early 1990s


Effort Indicators Recorded in tRFMO Data Bases• Globally since the 1990s, purse seine effort (sets) has also grown at

an average pace of about 2% per year.• During this time, the growth in floating object purse seine effort

increased by 70%, compared to about 20% for free-school purseseine fishing effort.

• Floating object purse seine fishing is about 50% more productive (in tper set) than free-school fishing for the three tropical tunas incombination and about twice as effective for skipjack.

• For yellowfin the relative efficiency of floating object fishing is aboutthe same as for free schools, although the size of yellowfin caught onobjects is much smaller than for free schools.

• The relative efficiency of object sets is about 10 times that for free-school fishing for bigeye and the fish taken are typically much smaller(~50 cm FL for fish caught on FADs and >100 cm FL for free schoolfish).


Tendency in effort recorded for purse seineSince the mid-1990s, the number of fishing sets recorded for free school and object-oriented sets hasgrown at about 2.8% per year. Since 1990, though, object-oriented sets sets have grown by about70% compared to a more modest gain for free-school sets.

The global pattern is not the same in all ocean areas and mostly reflects the Western Pacific. Otherthan in the western Pacific, there has been a general reduction in free school sets recorded comparedto the earliest part of the time series examined.


Relative Efficiencies of Object and Free School SetsGlobally, the relative efficiency of object-oriented sets compared to free school sets (in t) is higher,except for yellowfin tuna. Values above 1 indicate that catch per set in object-oriented sets is higher(more efficient) than free school sets, thus leading to increased capacity to catch fish with increasedeffort made by FAD fishing.


Increases in FAD sets per day

For the EU & Associated fleets in the Atlantic and Indian Oceans, increases in the frequency ofFAD sets per fishing day are evident which is a pattern consistent with increasing efficiency forcatching fish via FAD fishing in these fleets. This pattern is likely linked to technologicalimprovements through modernization of the fleet, improvements in instrumented buoys and otherfactors involved in effort creep. This level of detail is not generally available through the tRFMOsfor other fleet segments, but is likely indicative.


Fleet and FAD Indicators• The large-scale global purse seine fleet in 2013 is

uncertain but may be somewhat above 700 vessels.• FAD management plans which would permit monitoring

deployment and usage patterns are not yet in placeacross the tRFMOs

• Nearly 13,000 aFADs support around 8,000 vessels thatharvest tuna and tuna-like species, among others. Theratio of aFADs per vessel is 1.6, which is 100 fold lowerthan the ratio of dFADs per vessel using dFADs.

• The current level of annual dFAD deployments could beon the order of 91,000.


Purse Seine Vessels Authorized to Fish for Tropical Tunas


How Many aFADs?• Globally, aFADS exceed 73,000: ~60,000 are in the Mediterranean for dolphin fish.• Nearly 13,000 aFADs, supporting ~8,000 vessels harvesting tuna and tuna-like species, among others.• Indonesia, Philippines, Thailand and Papua New Guinea account for about 85% of aFADs targeting

tunas.


How Many dFADs?• Annual dFAD deployments ~91,000, but adequate global monitoring system makes this estimate highly

uncertain.• ~ 60% of the potential global dFAD deployments could occur in the western central Pacific, followed by

the eastern Pacific Ocean (~20-25%) and at a lower level in the Atlantic and Indian Oceans (around 10%each). Corresponds number of sets recorded for 2012: 50% in WCPO, 25% in EPO, 13% in IO and 10%in AO.


Status of Tropical Tuna StocksThere are 13 stocks of tropical tunas aroundthe world.

All except yellowfin in the Atlantic and in theeastern Pacific were found to be at healthybiomass levels in the most recent stockassessments.

In terms of exploitation level, all of the skipjackstocks were experiencing a low fishingmortality rate, and although some of theyellowfin and bigeye stocks were experiencingfishing mortality levels in excess of FMSY, mostwere being adequately managed to bring theexploitation levels to levels at or below FMSY.

The bigeye stock in the western Pacific,however, was experiencing high exploitationand management measures in place werejudged insufficient to reduce that rate to orbelow FMSY


Status of Tuna Stocks Fished with FADs• 93% of the recent tropical tuna catch came from healthy stocks and

a high proportion of that came from fisheries using FADs, mostlydue to skipjack.

• The use of FADs does not necessarily lead to overfishing (highexploitation) of tropical tunas, although harvesting large amounts ofcertain small tunas (e.g. bigeye or yellowfin) can reduce long-termpotential MSY.

• While the tropical tuna stocks impacted by FAD (and other) fishingare mostly in healthy condition, further increases in fishing pressurecould well change that picture.

• Unabated, the continued growth of FAD fishing for tropical tunas atthe pace witnessed over the past few years would increase overallfishing pressure on these stocks unless compensated by reductionsin other fisheries affecting these stocks.


By-catch Impacts• FAD fishing can cause adverse population effects on by-catch species, but in

the world’s oceans there are either management measures or researchprograms in place expected to mitigate these effects.

• In terms of tonnage, available estimates place the by-catch species at about 2%of the targeted tuna catch in global purse seine FAD fishing, although there isvariability by ocean region and can range to 8% in the Atlantic.

• Best Practices have been identified for use in purse seine fishing on FADs andthese have been communicated to a broad range of vessel owners and skippersthrough workshops conducted across the globe to accelerate their uptake by theglobal fleet.

• Research conducted in collaboration with fishers is continuing to in search ofadditional techniques in order to mitigate adverse effects on by-catch speciesand the environment.


By-catch: Sharks & Turtles

• Sea turtles are known to be among the by-catch in PS FAD fisheries, althoughthe number of turtles that die in purse seine fishing operations is much smallerthat in other gears, such as longline.

• PS FAD fishing operations catch several species of sharks, some of which(e.g. oceanic white tip and silky sharks) appear to have been declining inabundance in recent years. Entanglement and unobserved mortality can be asignificant problem, especially if FAD designs use underwater netting materialswith large mesh sizes.

• A Best Practice to mitigate entanglement is use of non-entangling FADs.• Other Best Practices involve safe handling and live release of by-caught turtles

and sharks• Research on other alternatives (e.g. release panels) is underway.


By-catch: Finfish• A fish aggregation around a floating object can have 15

or even more species (e.g. mahi mahi, rainbow runners,oceanic triggerfish, wahoo, etc.), in addition to skipjack,yellowfin and bigeye tuna.

• An issue with these by-catches is waste, since themajority (except in Eastern Atl) of these resilient speciesare discarded at sea.

• Requiring full retention of this by-catch component canmitigate this issue to a large degree and tRFMOs havemoved in that direction by requiring such for tunas forpurse seine fishing.

• Furthermore, the volume of by-catch can also bemitigated by simply avoiding setting on small (<10 t)aggregations, since proportionally higher volumes of by-catch species occur in small aggregations.


Recommendations• Recommendation 1. Avoid further increase in fishing pressure on

tropical tuna stocks by further increase in FAD fishing withoutcompensatory reductions in other fisheries.

• Recommendation 2. Implement an adequate, harmonized FADdeployment and utilization monitoring system through the tRFMOs.

• Recommendation 3. Institute a unified system of unique vesselidentification to allow tracking of vessel performance at theoperational level through time across the tRFMOs.

• Recommendation 4. Minimize by-catch species through applicationof and adherence to «Best Practices» such as those alreadyidentified through collaborative research between scientists andfishers. Continue cooperative research to further test mitigationalternatives.


Recommendations• Recommendation 5. Monitor by-catch and verify the application of

such “Best Practices” through data collection systems, such as on-board observations (i.e. human, electronic, or both). Requirementsfor 100% observation coverage for purse seine FAD fishing shouldbe considered to permit full accounting of by-catch impacts.

• Recommendation 6. Make available detailed, operational level datathrough the tRFMOs for monitoring effort creep and its impact ongrowing fleet capacity. Provide vessel VMS and instrumented buoydata, with a suitable delays to ensure confidentiality.


Acknowledgements• Assistance provided by the tRFMO data base managers

– F. Forrestal (U Miami) kindly assembled these data• Colleagues who provided input, comments, suggestions and

encouragement:– H. Murua, and J. Santiago (AZTI), V. Restrepo (ISSF), G. Moreno, I.

Sancristobal and J. Murua (AZTI), A. Fonteneau (IRD, retired), W. Sokimi(SPC), P. Gervain (PLK Marine), S. Mailau (Tonga Government), M. Taquet(IFREMER) and W. Cortez (U Hawaii)

• These contributions substantially improved the work and resolvednumerous inconsistencies.

• However, any and all remaining errors and opinions are ourresponsibility.


the use of fads in tuna fisheries · fish). 12/02/2014 use of fads in tuna fisheries 16. tendency...

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