Warning lights are flashing for Atlantic tuna

Posted: 2 November 2007

Fishing wiped out Atlantic Bluefin tuna stocks in Northern Europe 50 years ago, according to a new study which finds that pressure on the remaining stocks is pushing the entire species to the edge of extinction.

Every summer in the early 1900s, Northern European waters from Holland to northern Norway teemed with Atlantic Bluefin tuna, some three metres long and weighing 700 kilogrammes, according to historical fishing records. Few could catch the powerful, fast-swimming fish until the 1930s and 1940s when bigger, faster boats with better catch gear were designed.

"The Bluefin population crashed in the 1960s and more than 40 years later it still hasn't recovered," said Brian MacKenzie of the Technical University of Denmark, who led the study to be published in the journal Fisheries Research.

"You simply don't see bluefins in these waters any more," MacKenzie told IPS.

There is a clear parallel to the more recent collapse of once abundant Northern Cod stocks. Also fished into near extinction on the other side of the Atlantic, the Cod have not recovered despite a no-fishing ban for the past 15 years.

Atlantic Bluefin

"I'm afraid what happened to the Bluefin is similar to what happened to the Northern Cod," he said.

Tuna fishing, Sardinia, Italy. Photo: Antonio Pais/FAO
Tuna fishing, Sardinia, Italy. Photo: Antonio Pais/FAO
Tuna fishing. A raised landing net brings the tuna to the surface in Sardinia, Italy.© Antonio Pais/FAO
Meanwhile, Atlantic Bluefin are under intense fishing pressure, including use of spotter planes and helicopters, in the Mediterranean Sea region. Bluefin are highly desired by the Japanese sushi market, with single fish selling for US$60,000 (£30,000)- the record is 174,000 dollars for a 444-pound Bluefin tuna.

The Atlantic Bluefin fishery is regulated by the 44-nation International Commission for the Conservation of the Atlantic Tuna (ICCAT) that set a 2007 quota of 29,000 tonnes, down from the previous year's quota of 32,000 for the Mediterranean and eastern Atlantic.

Marine biologists and environmental groups say the ICCAT quota is twice what is sustainable. Moreover the WWF, an international environmental group, says illegal fishing is rampant in the region and an independent study revealed the actual annual tuna catch approached 50,000 tonnes.

Electronic tags

Atlantic Bluefin range across the entire Atlantic Ocean with three distinct populations. The largest population breeds in the Mediterranean Sea, another is found in the western Atlantic and the third is found in the South Atlantic and is considered by many to be an endangered species, explains Barbara Block, a marine biologist at Stanford University and chief scientist of the Census of Marine Life Tagging of Pacific Predators programme and the Tag-a-Giant Bluefin tagging programme.

The western Atlantic population that breeds in the Gulf of Mexico is also in poor shape, suffering from a 90 per cent decline in fish of breeding age, but despite that there is commercial fishing with a quota of 2,100 tonnes for this year.

"There are few Bluefins mature enough to breed in the Gulf of Mexico," Block, one the world's foremost tuna experts, said in an interview.

Block and colleagues have been placing electronic tags on Bluefins for several years to learn more about their movements and breeding areas.

Two giant Bluefins tagged off the north of Ireland in 2004 wound up more than 5,000 kms apart eight months later. One travelled 6,000 kms southwest in 177 days past Bermuda to waters about 300 kilometres northeast of Cuba; the other remained in the eastern Atlantic and moved off the coasts of Portugal.

Gold rush mentality

"These tagging data potentially provides new evidence that mixing is occurring in the northern waters of the eastern Atlantic and complement prior data showing that the western and eastern stocks of north Atlantic Bluefin mingle in rich foraging grounds of the central Atlantic," she said.

That means Japanese and European tuna hunters off Ireland and elsewhere in the North Atlantic are likely harvesting the increasingly rare western Atlantic Bluefin and counting them as eastern Atlantic Bluefin.

"The western Atlantic population may vanish unless quotas are dramatically lowered in the east," Block said.

Because millions of dollars can be made catching tuna, there is a "gold rush mentality" where "no one wants to follow rules", including not fishing in tuna breeding grounds, she said.

Moreover, because breeding is such a high-stress time for tuna, even closure of breeding grounds to tuna fishing as has been done in the Gulf might not be enough, according to other new data Block and colleagues will publish in the journal Marine Biology.

Twenty-eight western Atlantic Bluefins were given special sophisticated tags that recorded their location, depth, water temperature, light level and their abdominal temperature. Researchers found that a majority of Bluefins (some weighing up to 300 kilogrammes) gravitated to the warm waters near the Florida straits and the western part of the Gulf of Mexico for breeding. Actual physiological measurements of wild tuna courting and mating were obtained during this study.

"They're a big, hot fish and easily stressed at this time," Block noted.

For that reason and to prevent tuna from being caught as bycatch, all fishing should be banned near their breeding grounds during the breeding season, she added.

June ban

That seems unlikely to happen. At an ICCAT meeting this past July, little action was taken on illegal fishing, according to the WWF. The oversized and well-financed tuna fleet can easily take 50,000 tonnes in the Mediterranean and East Atlantic, despite a quota allowing only 29,000 tonnes.

"This failure of ICCAT contracting parties to do the right thing is effectively an encouragement of illegal fishing, since capacity far oversteps quota," said WWF's Sergi Tudela, who attended the meeting as an official observer.

"The only way now to guarantee a reduction in fishing effort and facilitate real stock recovery is to impose a ban during the month of June when the bulk of catches are taken," Tudela said in a statement.

When Bluefins started to vanish from the Northern European waters in the 1960s, there was some concern but no action was taken and soon after it was too late, said MacKenzie.

"Today few people know the seas around Northern Europe were once filled with these huge majestic fish" he said. "The warning lights are flashing right now for the rest of the world's remaining Bluefins."

Source:IPS, November 2007

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