Another Possible BP Casualty: Bluefin Tuna

Tokyo's Tsukiji fish market is a long way from the oil-drenched waters of the Gulf of Mexico. Starting at 4 a.m. every day, agents from Japanese trading companies bid for bluefin tuna and other fish from around the world that lie side by side on the floor of a cavernous warehouse. Bluefin is a mainstay of any sushi restaurant in Tokyo, and the giant fish—sometimes weighing more than 500 pounds—is the king of Tsukiji. BP's spill is billowing near one of two spawning grounds for the Atlantic variety of bluefin (the other is in the Mediterranean). For now, fishmongers in Tsukiji say they're not worried about the effect the BP (BP) disaster will have on the bluefin population. "If there's an impact," says one trader for local wholesaler Umino who won't give his full name, "we won't see it for a few years."

Go to the U.S., though, and you'll find plenty of scientists, state officials, and fishermen wondering already about the disaster's impact on the bluefin. Japan last year consumed about 80 percent of the world's bluefin catch, or 52,000 tons, according to the Japanese Ministry of Agriculture, Forestry & Fisheries. A large chunk of that comes from the Atlantic. The chemicals BP is using to contain the spill could damage the bluefin larvae produced by adults that spawned in the Gulf. "The oil plus the dispersants are likely to have a huge effect," says Bill Fox, managing director for fisheries at the World Wildlife Fund. For the Atlantic bluefin, "this is a real blow."

Scientists from several institutions, including the National Oceanic & Atmospheric Administration, are trying to figure how big the blow really is. Bluefin tuna live for up to 40 years, and in that time many repeat the same cycle endlessly: spawn in the Gulf or the Mediterranean, then head to the teeming waters of the North Atlantic to feed. Spawning in the Gulf takes place from March to June, and the spawning ground overlaps with the oil spill. Bluefin need clean ocean water to spawn—adults spawn at the surface, so they may have gotten coated with oil while spawning this year.

No one is sure exactly what happened this year when the Gulf spawning season started. If there is an effect, "we'll see [it] in about three to four years," says Greg Stunz, marine scientist at the Harte Research Institute for the Gulf of Mexico in Texas. That's when the bluefin tuna born this year reach adult size. A weakened, underpopulated generation of bluefin would show something serious happened. Some fishermen, though, say enough of the spawning occurred before the Apr. 20 spill to minimize the damage.

Others in the industry think it will prove impossible to separate the spill's impact from the general collapse of the bluefin population. Stocks of fish that spawn in the Gulf are at just 10 to 20 percent of their 1960s levels, Fox says. In the Mediterranean, the spawning ground that accounts for more than half the annual Atlantic catch, severe overfishing has led to a similar decline in supply. Environmentalists clashed with fishermen off the coast of Malta in June, and the European Commission called a halt to fishing early after the quota was used up. The dramatic drop in the bluefin population has prompted international regulators to make sharp cuts in the permissible catch. In March, though, Japan successfully fought a proposed Atlantic ban by the U.S. and the EU. The average price for bluefin tuna in Tsukiji, meanwhile, has risen 26 percent, to $37 a kilo, since 2005. Last winter one hefty specimen fetched $177,000 at Tsukiji.

The problems in the Atlantic—and similar declines in the Pacific—are leading the bluefin industry in Australia to sense an opening for their bluefin, long considered an inferior cousin by Japanese consumers. The Australians last year launched a rebranding campaign in Japan, changing the name of the fish from indo maguro, or Indian bluefin, to minami sodachi maguro, or beautiful wave-bred bluefin. "The basic aim was to get more Japanese to taste southern bluefin and recognize that there is no real difference," says Brian Jeffriess, chief executive officer of the Australian Southern Bluefin Tuna Industry Assn. According to Jeffriess, the price per kilo of Australian-caught bluefin has gone up to $19, a 40 percent increase since March. Japanese trading companies such as Mitsubishi that buy frozen bluefin are expected to agree to an even higher price for Australian bluefin soon. The BP disaster "will inevitably have a big effect at a time when there's already uncertainty about the sustainability of the [Atlantic] stock," says Jeffriess.

The bluefin are hardy creatures, and there's still reason to hope they can withstand the latest setbacks. "Once they get to full size, there's nothing that can catch them other than humans," says the WWF's Fox. "But every year we move into more uncharted territory."

The bottom line: The oil spill in the Gulf may hit a bluefin tuna population already threatened by years of overfishing.

With Caroline Winter

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