Champion long-distance swimmers and among the ocean’s top predators, tuna are truly one of the ocean’s most magnificent and valuable fish. However, the world’s Tuna fisheries face a number of urgent problems that are threatening their continued existence. Leisure Boating investigates.
However you like your Tuna – canned, as a steak, or as sushi or sashimi – you’d find them just about everywhere. Caught, traded, processed, shipped, and eaten around the world, Tuna is a global commodity and vitally important for the economies of both developed and developing countries alike.
Tuna is big business. In 2002, the value of the Tuna export catch was a massive US$ 5 billion. Bluefin Tuna are the most valuable fish in the sea, with one specimen selling for a record-breaking US$173 600 at Tokyo’s Tsukiji fish market in 2001.
Together, the seven principle market species, Albacore, Atlantic Bluefin, Bigeye, Pacific Bluefin, Skipjack, Southern Bluefin and Yellowfin, are the single-most important resource exploited on the high seas, accounting for over 7% of total marine capture fisheries production, and 11% of the total value of fish landings for consumption.
But Tuna are in trouble. All 23 identified, commercially exploited stocks are heavily fished, with at least nine classified as fully fished and a further four classified as overexploited or depleted. Three stocks are classified as critically endangered, three as endangered, and three as vulnerable or facing extinction.
This shouldn’t be the case. The first warning about the declining Tuna stocks came over 40 years ago, in the 1960s. Since then, five regional fisheries management organisations (RFMOs) – the main mechanism for regulating fishing on the high seas, where most Tuna catches occur – have been established with a general objective to conserve and sustainably manage Tuna stocks in different oceans.
Alarming Tuna stock declines, poor conservation and management strategies, high levels of illegal, unreported and unregulated (IUU) fishing and significant bycatch of sharks, marine turtles, seabirds, small cetaceans, juvenile Tuna and other fish are some of the main problems identified by the RFMOs.
Additionally, a number of international laws and internationally agreed standards and protocols have been developed to guide sustainable fisheries management, all of which are applicable to the Tuna RFMOs and their member states. However, the Tuna RFMOs have generally failed to meet their own obligations, as well as those set by the international community to prevent over-exploitation of Tuna or protecting the wider ecosystem.
While there are signs of leadership in some areas, the problems are all too familiar: Tuna fishing fleets have been allowed to grow too big, appropriate catch limits have either not been imposed, or are not being respected, illegal unreported and unregulated fishing is a major problem in several Tuna fisheries, and large numbers of juvenile Tuna are caught before having had the chance to breed.
John Duncan, manager of WWF Sustainable Fisheries Programme, said that each Tuna species have different biological attributes (reproduction, growth, lifespan rate) which can either make them more or less vulnerable to fishing pressure.
“Some of these species such as the Bluefin Tuna have been heavily fished over the last few decades with the result that their populations are now considered to be overfished. Although this is unlikely to lead to complete extinction (if unchecked), it’s likely to lead to what is known as commercial extinction, which occurs when these Tuna are no longer commercially viable,” said John.
Ever growing fleets and catches
People have been fishing for Tuna for at least 4 000 years. Until the second half of the 20th century, most Tuna fleets were small and fished mostly in coastal areas. This all changed in the 1940s, when increased demand led to the first large-scale industrial fisheries. This marked the beginning of the large-scale decline of the world’s Tuna stocks.
Driven by continued demand and helped by a series of technological developments, industrial Tuna fleets grew ever-larger and ever-more efficient from the 1940s onwards. By the 1980s, industrial longline and purse seine Tuna fleets from the EU, US, Japan, Korea, Taiwan and Venezuela had spread throughout the world’s oceans.
During the 1980s and 1990s, many coastal states also began to fish for Tuna, and today, Tuna are fished by over 80 countries worldwide. The combined capacity of the world’s tuna longline and purse seine vessels has grown so much that it has actually overtaken the capacity needed to take the current levels of catch.
The steady growth in tuna fleets has been matched by a steady growth in Tuna catches – which are now 10 times higher than in 1950, reaching over 4 million tons in 2002, 2003 and 2004.
If an army marches on its stomach, then the key item in the kit bags of the Roman legions that conquered Southern Europe about 2 000 years ago, was dried Bluefin Tuna. But having survived the demands of the Roman conquest, the species – each of which can weigh as much as 650 kg and live up to 40 years, might finally have met its match in the contemporary global appetite for sushi.
“As technology has improved and the demand for Tuna has grown, particularly with the increasing global popularity of sushi, many tuna stocks have come under
increasing pressure. The exceptionally high value placed upon Bluefin Tuna now as a result of its popularity as sashimi in sushi restaurants has increased the incentives for illegal fishing and made it increasingly difficult to effectively manage its trade,” continued John.
If environmentalists and marine scientists are right, the world’s remaining stocks of Bluefin Tuna, 90% of which are in the Mediterranean, could be on the verge of extinction. Says Alain Fonteneau, a marine biologist for France’s government-run institute for development research in Montpellier: “if we do nothing, in five years, we will fish the last Bluefin Tuna”.