Fishing wiped out Atlantic Bluefin tuna stocks in Northern Europe 50 years ago, according to a new study, while ongoing pressure on the remaining stocks is pushing the entire species to the edge of extinction, writes Stephen Leahy for IPS.
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.
“I’m afraid what happened to the Bluefin is similar to what happened to the Northern Cod,” he said.
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 60,000 dollars – 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.
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 percent 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.
“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.