The majority of canned tuna worldwide is caught using purse seine nets with fish aggregation devices. A FAD can be any floating object – fisherman have been using FADs made of branches, palm fronds and logs for centuries.[1] Here in the Pacific Ocean we have seen a barrel drum, large missile-like objects and a haphazard collection of junk as well as more sophisticated FADs consisting of netted buoys and a radio beacon.
Experts are still trying to understand why these floating devices attract so much marine life[2] – theories include “visual stimulus in an optical void”[3], a point of reference, or an attraction to the marine matter that attaches to floating objects. What is certain is that they work.
Fishermen use them as a surefire way to catch a school of fish – usually skipjack tuna, but problems abound because when purse seine nets are set around FADs, everything underneath is caught and usually ends up dead.
Firstly, FADs attract baby tuna, often from at-risk species like bigeye and yellowfin. Fishing juveniles obviously damages the reproductive process, preventing fish from replenishing their stocks. In fact, according to the University of Hawaii’s pelagic fishing programme, FADs fished by purse seine nets are a major contributor toward yellowfin and bigeye tuna stocks being pushed toward depletion [4]. Both of these species are overfished and have been listed on the International Union for the Conservation of Nature’s red list as vulnerable and near-threatened respectively. At least 15 to 20 % of a FAD catch is expected to be juvenile bigeye and yellowfin.[5]
Secondly, FADs often trail netting which seems to add to their attractiveness to tuna, and can snag turtles, sharks, and other creatures, causing injury and death. [6] From the kings of the marine food chain - sharks - to turtles, manta rays, mahi mahi, and many other marine species, much more than just tuna is hauled up in the purse seine net as well, often dying in the process. These animals are euphemistically called ‘bycatch’ and FAD purse seine fishing can incur ten times the amount of other species killed as non-FAD fishing.[7]
For a disturbing look at some undercover footage of bycatch on board a tuna boat watch this film.
Globally it is estimated that FAD associated bycatch may now be as high as 182,500 tonnes annually.[8] This global bycatch would fill the equivalent of nearly 1 billion tins of tuna every year.[9]
Research presented to the Western and Central Pacific Fisheries Commission (WCPFC) Science Committee in 2009 showed that the use of FADs led to significant bycatch of bigeye and yellowfin, turtles, marlin, barracuda, whale sharks, silky sharks, olive ridley turtles and juvenile bigeye and yellowfin tuna.[10]
In particular, more than 75% of the oceanic pelagic shark and ray species are classified as threatened or near threatened by the International Union for the Conservation of Nature.
Whalesharks, IUCN red listed globally as vulnerable, are also caught incidentally in purse seine nets,[11] and in fact are sometimes used as living FADs by purse seine vessels. This is something Greenpeace is campaigning on to ban the intentional setting on whalesharks.
Longlining, gillnet and trawl fisheries are the main cause of turtle deaths, but purse seines using FADs are also responsible for the deaths of turtles.[12]
Combine the ruthless efficiency of FADs with the more widespread problem of overfishing - larger boats with greater capacity chasing fewer and fewer fish – and you begin to see the problem for remaining tuna stocks. Years of bad management and overfishing has left tuna stocks in crisis. The majority of tuna stocks are in decline and appear set to continue on this downward slide.
By 2006, of the 23 commercially exploitable tuna stocks identified:
• At least nine were classified by tuna management bodies as fully fished
• A further four were classified as overexploited or depleted
• Three were classified as critically endangered
• Three were endangered, AND
• Three were vulnerable to extinction.[13]
Without monitoring and effective management, even stocks of the healthiest remaining species, like skipjack, could suffer.[14][15][16][17]
And the real picture could be a lot worse than the formal stock assessment. Data is notoriously hard to gather and formalize across all tuna markets.
On the bright side, consumers, industry leaders and retailers are demanding a move away from FADs and towards more sustainable ways of fishing.
Recently, every major tuna brand in the United Kingdom committed to abandoning FADs, and leaders in the fishing industry are committing parts of their fleets to free school, or non FAD fishing to meet this growing consumer demand.
Pole and lines fisheries, in which each tuna are caught individually, reduce bycatch to almost zero.
There are other things that can be done. Retailers and tuna brands should endorse the creation of a global network of large scale marine reserves and should publicly support the call for the Pacific Commons to be off limits to fishing and ensure they are not selling any canned tuna caught in this area.
What you can do
Send a message to Sealord, New Zealand’s largest canned tuna brand, urging it to stop buying tuna from companies destroying ocean life in the Pacific.
Footnotes
[1] Dempster, T and Taquet, M: Fish aggregation device (FAD) research: gaps in current knowledge and future directions for ecological studies, Reviews in Fish Biology and Fisheries March 2004; 14(1) : 21 – 42 http://archimer.ifremer.fr/doc/2004/publication-721.pdf
[2] Dempster, T and Taquet, M: Fish aggregation device (FAD) research: gaps in current knowledge and future directions for ecological studies, Reviews in Fish Biology and Fisheries March 2004; 14(1) : 21 – 42 http://archimer.ifremer.fr/doc/2004/publication-721.pdf
[3] Hunter, JR and Mitchell CT (1966) "Association of fishes with flotsam in the offshore waters of Central America". US Fishery Bulletin, 66: 13-29
[4] University of Hawaii, ‘The Associative Dynamics of Tropical Tuna to a Large-Scale Anchored Fad Array’, 2008 http://www.soest.hawaii.edu/PFRP/biology/holland_itano_png.html
[5] International Seafood Sustainability Foundation, FAD: Fact aggregating Document, http://iss-foundation.org/resources/downloads/fad-fact-aggregating-document/
[6] ISSF Meeting on mitigation of by-catches in the Tuna Purse Seine Floating Object Fisheries – Final Report AZTI Sukarrieta, Spain, 24-27 November 2009. http://www.iss-foundation.org/FileContents.phx?fileid=e7f00ec6-01eb-4ba7-9ede-42f229199955, p15
[7] International Seafood Sustainability Foundation, FAD: Fact aggregating Document, http://iss-foundation.org/resources/downloads/fad-fact-aggregating-document/
[8] Calculation based on the FAO estimates that total purse seine catches were 2.607.201 MT in 2007. 70% FAD with 10% bycatch. Greenpeace International, ‘A Growing FAD’: Kobe-II Bycatch Workshop, Brisbane 23-25 June 2010. It had previously been estimated that total bycatch from the use of FADs amounted to some 100,000 tonnes every year: T. Dempster and M. Taquet ‘Fadbase and Future Directions for Ecological Studies of Fad-Associated Fish’, 2005. http://www.spc.int/coastfish/news/Fish_News/112/Dempster_112.pdf
[9] 987,325,000 cans of tuna (i.e. almost 1 billion 185g cans)
[10] H.H. An et al (2009). ‘Effects of set type on catch of small-sized tuna by the Korean tuna purse seine fishery in the WCPO’. Scientific Committee Fifth Regular Session, 10-21 August 2009, Port Vila, Vanuatu. Western and Central Pacific Fisheries Commission (WCPFC), Kolonia, Pohnpei. WCPFCSC5- 2009/FT WP-02
[11] M.D. Camhi et al (2009). The Conservation Status of Pelagic Sharks and Rays. Report of the IUCN Shark Specialist Group Pelagic Shark Red List Workshop. Tubney House, University of Oxford, UK, 19–23 February 2007 http://cmsdata.iucn.org/downloads/ssg_pelagic_report_final.pdf
[12] From 2,400-8,600 caught in this fishery annually over the same period. Molony (2005). WCPFC. Estimates of the mortality of non-target species with an initial focus on seabirds, turtles and sharks. WCPFC–SC1 EBWP–1 http://www.wcpfc.int/doc/eb-wp-1/estimates-mortality-non-target-species-with-initial-focus-seabirds-turtles-and-sharks
[13] J. Maguire et al, ‘The state of world highly migratory, straddling and other high seas fishery resources and associated species’, 2006. http://www.fao.org/docrep/009/a0653e/a0653e00.htm
[14] IOTC (2009). IOTC Report of the Twelfth Session of the Scientific Committee, Victoria, Seychelles, 30 November-4 December, 2009 IOTC-2009-SC-R[E] http://www.iotc.org/files/proceedings/2009/sc/IOTC-2009-SC-R%5BE%5D.pdf
[15] WCPFC 2010. The Commission for the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific. Ocean Scientific Committee Fifth Regular Session Port Vila, Vanuatu 10-21 August 2009. Summary report. http://www.wcpfc.int/meetings/2009/5th-regular-sessionscientific-committee
[16] ICCAT (2008). Skipjack executive summary. In: Report of the 2008 ICCAT yellowfin and skipjack stock assessments meeting. Florianópolis, Brazil, 21–29 July 2008. SCRS/2008/016 – YFT & SKJ Assessment. www.iccat.int/Documents/SCRS/ExecSum/SKJ_EN.pdf
[17] IATTC (2010). Fishery Status Report 7. Tunas and billfishes in the Eastern Pacific oceans in 2008. Inter-American Tropical Tuna Commission. La Jolla, California 2010. http://www.iattc.org/PDFFiles2/IATTC-80-05-Tunas-and-billfishes-in-the-EPO-2008.pdf