Tuna, Conservation and ICCAT

Tuna is one of the most popular and widely eaten food fish in the world, but the intensive commercial pressure on this species means that many tuna stocks are depleted. Attempts to reduce the intensity of tuna fishing and allow stocks to recover have proved ineffective with the ICCAT (International Commission for the Conservation of Atlantic Tunas), the organisation which is responsible for managing and protecting tuna species, coming in for particular criticism due to its ineffective attempts to stop the decline.

Tuna Species

Although many simply refer to tuna as a single species there are a number of true tuna, as well as related tuna-like species. There is a great deal of difference in the sizes between species: the largest, most intensively fished and most valuable is the Atlantic bluefin tuna which can (at its very largest) be 14 – 15ft in length, weigh 1500lb and sell for tens of thousands of pounds, whereas the much smaller, cheaper and more numerous skipjack tuna grows to a maximum size of around three feet in length. The division between the different tuna groups is shown below:

Tuna Groups

Behaviour and Feeding

Tuna are adapted to swim at great speeds. They have powerful, streamlined bodies and slim, stiff fins which help them achieve both great acceleration and top speed – the fastest species of tuna is the yellowfin which is thought to be able to reach speeds of up to 50mph. This speed is helped by the fact that tuna can conserve heat that has been generated by their muscles. This allows them to raise their body temperature higher than the water they are in meaning that tuna can live in a wide range of sea temperatures.

Tuna Species

Tuna are a shoaling species that can live in vast groups. Tuna are predators which feed on smaller fish such as herring and mackerel, with even huge fully grown bluefin tuna preferring to hunt these species rather than larger prey.

Conservation, Overfishing and ICCAT

ICCAT is an intergovernmental organisation that is responsible for the conservation of tuna and related species in both the Atlantic Ocean and other seas which connect to the Atlantic. While the aims of ICCAT are well-intentioned, the organisation has been heavily criticised over a number of decades by a wide range of different organisations for its perceived failure to protect tuna.

Bluefin Tuna Catches
Bluefin tuna catches have declined since the 1950s.

Most of this criticism is based on ICCAT’s failure to halt the decline of tuna stocks and its reluctance to put in force any measures which would meaningfully reduce the levels of commercial fishing for tuna. ICCAT is often seen as putting the short-term demands of the commercial tuna fishing industry ahead of the long-term sustainability of tuna species. For these reasons conservationists often claim that the acronym ICCAT should stand for the International Conspiracy to Catch All Tuna.

Background and Operations of ICCAT

Most tuna species live and feed far out to sea and migrate great distances putting them outside of the jurisdiction of any single nation. Establishing an international intergovernmental organisation was therefore seen as the best way of managing the stocks of tuna and controlling the commercial exploitation of the species. This led to the creation of ICCAT in 1966, with the convention formally coming into force in 1969.

ICCAT is responsible for managing tuna stocks.

The ICCAT convention area covers around one-quarter of the entire world’s oceans. ICCAT carries out research in the areas of ecology and oceanography with a particular emphasis on the ways in which commercial fishing affects the stock abundance of tuna and tuna-like species. As well as this ICCAT compiles data on the long-term trends of tuna stocks and also gathers data on other species which may be caught as bycatch during tuna fishing. Currently, fifty-two parties are members of ICCAT, including Japan, the United States, Canada, the United Kingdom and the European Union. The official languages of ICCAT are English, French and Spanish. While ICCAT’s research and regulations cover over thirty species the organisation lists the following as being the main species of direct concern to its operations:

  • Atlantic bluefin tuna (Thunnus thynnus)
  • Skipjack tuna (Katsuwonus pelamis)
  • Yellowfin tuna (Thunnus albacares)
  • Albacore tuna (Thunnus alalunga)
  • Bigeye tuna (Thunnus obesus)
  • Swordfish (Xiphias gladius)
  • White marlin (Tetrapturus albidus)
  • Blue marlin (Makaira nigricans)
  • Sailfish (Istiophorus albicans)
  • Spearfish (Tetrapturus pfluegeri)
  • Spotted Spanish mackerel (Scomberomorus maculatus)
  • King mackerel (Scomberomorus cavalla)
  • Black skipjack tuna (Euthynnus alletteratus)
  • Frigate tuna (Auxis thazard)
  • Atlantic bonito (Sarda sarda)


There are many examples of ICCAT’s mismanagement of Atlantic tuna stocks, with many conservation organisations claiming that ICCAT’s track record of sustained failure means that it is unfit for purpose and needs to be either completely reformed or abolished and replaced with a new organisation. Some of the criticisms of ICCAT are detailed below.

By the early 1980s it was apparent that industrial fishing of tuna had decimated stock levels and a major reduction in commercial fishing intensity was necessary to allow stocks to rebuild. In 1981 ICCAT stated that tuna catches should be as near to zero as possible and set a limit of 1,160 tons. Within a year this is increased to 2,260 tons and by 1999 pressure from the commercial fishing industry meant that ICCAT had raised the maximum tuna limit at 32,000 tons. Source.

In 2009 it was estimated that the stock of Atlantic bluefin tuna is around 15% of its size before industrial commercial fishing began. Despite this ICCAT sets the next years quota at 13,500 tons, leading Susan Lieberman, Director of International Policy for the Pew Environment Group to say:

“Since its inception, the International Commission for the Conservation of Atlantic Tunas has been driven by short-term commercial fishing interests, not the conservation ethic implied by its name . . . Only a zero catch limit could have maximized the chances that Atlantic bluefin tuna could recover to the point where the fishery could exist in the future.” Source.

In late 2010 it emerged that the 2009 quota, widely regarded as far too high by conservation groups, would be cut by only 4%, meaning that 12,900 tons would be caught each year. Scientists had warned that the quota should be no higher than 6,000 tons if the numbers of bluefin tuna were to recover. The idea of no-fishing zones was also dismissed by ICCAT. This led Dr Sergi Tudela, Head of World Wildlife Fund’s Mediterranean’s Fisheries Programme to say:

“After years of observing ICCAT and countless opportunities to do the right thing, it is clear to us that the commission’s interests lie not in the sustainable harvesting of bluefin tuna but in pandering to short-term business interests.” Source.

Greenpeace also stated that the word ‘conservation’ should be removed from the name of ICCAT.

Furthermore, due to illegal, unregulated and unreported fishing of tuna, the true catch levels could be double official figures, meaning that ICCAT should take an even stronger approach to reducing quotas. Furthermore, as all tuna species are under such immense commercial pressure the average size of tuna caught in the ICCAT area has been consistently reducing over recent decades, as more individual fish are needed to reach quotas. The result of smaller and smaller fish being caught is that many fish are being taken from the sea before they have had a chance to reproduce, further exacerbating the problem of declining stocks.

Tuna Fishermen
Tuna is one of the most valuable commercial fish in the world.

One of the fundamental problems with ICCAT is that it has no powers of its own to penalise countries for overfishing – the power to enforce rules lies entirely with individual countries and the European Union. For example, ICCAT banned commercial tuna fishing operations using spotter planes to track down tuna shoals, but this practice still appears to be widespread, and until individual nation-states decide to take action to stop this practice it will continue. It is believed by many that in the ultra-competitive tuna fishery so much money is at stake that disregarding the rules is worth the risk as the chances of being caught and punished are so low.

The Future

While tuna numbers across the world remain under pressure there has been some good news. Bluefin tuna was one common in British waters, and even supported a big game fishery in the 1920s and 1930s, but had all but disappeared by the 1950s. Since 2014 they have made a return with multiple sightings of tuna being made all around the UK coastline and organisations such as Cefas confirming that the species is once again present in British waters. This corresponds with positive news on bluefin tuna stocks from the International Union for the Conservation of Nature (IUCN). The organisation has classed the species as Endangered on a global basis in 2011 but changed this to Least Concern in 2021. However, it is important to note that bluefin tuna are still classed as Near Threatened in Europe and Endangered in the Mediterranean by the IUCN, and the total number of bluefin tuna (as well as most other commercially valuable tuna and tune-like species) are still well below healthy numbers.

Related article: Atlantic Bluefin Tuna

It is difficult to calculate how much (if any) of the credit for this recovery can be given to ICAAT. The organisation divides opinion with many conservationists and environmental groups seeing it as a toothless talking shop that does little to protect tuna and instead provides commercial fishermen with the political cover to say they are working to protect stocks when they are in fact doing the opposite. Others take a more charitable view, seeing it as an organisation that faces a near-impossible task of having to satisfy the demands of both commercial fishermen and conservationists while having few meaningful powers of its own.

Tuna Market
While tuna numbers have shown a recovery in recent years, commercial pressure still mean that the long-term recovery of the species is far from certain.

The travails of ICAAT show the difficulty in managing the stocks of highly mobile migratory species which cover huge distances and require multiple governments to cooperate in order to manage stocks. Just as the EU’s Common Fisheries Policy has been heavily criticised for failing to prevent the decline of Europe’s fish stocks, ICAAT finds itself subject to similar criticisms. While the recovery of bluefin tuna provides some hope for the future this will need to continue for a considerable period of time before ICAAT can be considered to have achieved its aim of providing stable management of tuna stocks in the Atlantic Ocean.