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Spill may cut into N.E. bluefin catch

Oil could harm spawning sites

Researchers from the University of Southern Mississippi’s Gulf Coast Research Lab took this photo of a larval bluefin tuna. Researchers from the University of Southern Mississippi’s Gulf Coast Research Lab took this photo of a larval bluefin tuna. (Jim Franks)
By Beth Daley
Globe Staff / June 2, 2010

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OCEAN SPRINGS, Miss. — The fate of one of New England’s most prized fish may be unfolding more than a thousand miles away in the Gulf of Mexico.

Bluefin tuna — so desired by sushi devotees that a single giant fish fetches thousands of dollars — are believed to spawn off the United States only in the Gulf and mostly during April and May. This year, both coincided with the worst oil spill in the nation’s history.

As oil gushes up from the seabed and spreads, scientists are studying whether bluefin larvae the size of a pencil tip will survive the leak. The answer could have important consequences for New England, where many of the tuna migrate each year and where bluefin fishing season opened yesterday.

“I suspect the larvae and eggs won’t be able to escape if they [encounter] oil,’’ said Jim Franks, senior scientist at the University of Southern Mississippi’s Gulf Coast Research Laboratory.

Even before the spill, the numbers of bluefin in the region’s waters had fallen sharply, probably because of heavy fishing, and fishermen fear the government will now impose more restrictions on the size of the catch.

Yesterday, as the US Department of Justice announced a criminal investigation of the BP leak, the government expanded a no-fishing area in federal waters to almost 76,000 square miles, or 31 percent of the Gulf.

Meanwhile, BP tried again to funnel some of the leaking oil to a ship on the surface, a procedure that failed several weeks ago. Federal officials warned that the leak could continue into August, or beyond, until two relief wells can be drilled.

Franks and colleagues just returned from a 12-day annual cruise to one of the bluefin’s Gulf spawning grounds 250 miles offshore to collect larvae. They saw some oil sheens and oil globs there, about 50 miles from the leaking well.

The National Marine Fisheries Service also had a research vessel out collecting larvae as part of an annual survey. The data so far do not show a large overlap between the oil and Gulf spawning grounds, but much is still unknown, said Clay Porch, chief of the sustainable fisheries division at the Southeast Fisheries Science Center.

It’s unknown how adult bluefin — 1,400-pound torpedo-shaped behemoths that are believed to live at least 20 years — will fare in the spill. But scientists are most focused on the millions of eggs and larvae now in the Gulf because they cannot swim away from oil.

“The belief is they would not survive encounters with the oil. That could have a radical impact on an already severely depleted species,’’ Franks said.

But another scientist, Molly Lutcavage, research professor and director of the Large Pelagics Research Center at the University of Massachusetts Amherst, said some recent research suggests that bluefin along the East Coast may spawn at different times of the year in the Gulf and possibly in other places. While this work is preliminary, it means that the spill might not wipe out an entire age class of fish.

Once, the bluefin tuna’s strong-tasting reddish meat was considered so vile it was dubbed “horse mackerel.’’ But its fortunes shifted in the 1970s as Japan and other countries began prizing it for sushi and sashimi.

Today, large bluefin caught in New England are often packed in ice and flown to Japan to be served in restaurants.

New England fishing lore is filled with stories of high-speed chases of bluefin and the financial windfall from catching one — $3,000 or more for large ones these days.

The value of the US bluefin fishery is less than $10 million, according to the American Bluefin Tuna Association, but fishermen don’t have to catch many to nicely supplement their incomes from catching other species.

“It’s just a love I have for it — and so do a lot of people,’’ said Stephen Weiner, who catches bluefin with a harpoon out of Ogunquit, Maine.

But scientists say their numbers are at dangerous levels, some 70 percent lower than they were in the 1970s, and populations, while stable, have not rebuilt to historical levels. A US-supported effort to ban the international trade of bluefin tuna failed in March during United Nations-sponsored talks on the trade of endangered species.

Then last week, the San Francisco-based Center for Biological Diversity petitioned the federal government to place bluefin on the endangered species list.

“We were thinking about it prior to the oil spill, but that really lit a fire’’ for us, said Catherine Kilduff, a lawyer for the center who filed the petition. She said it could take two years for the petition to be heard. “We need to protect spawning stock.’’

US fishermen say a bluefin tuna assessment being conducted by the federal government this year will show the stocks are bouncing back. While fishermen say they are worried about the Gulf spill, they are just as fearful that any harm is being hyped by environmentalists to justify stricter regulation.

“Am I concerned that the nation’s worst environmental disaster is in an area where the tuna spawn this time of year — absolutely,’’ said Weiner. But, he added, nature protects species against disasters, such as by ensuring that tuna spawn in several areas in the Gulf over two months, and he is waiting to see what scientists say about the larvae before drawing any conclusions.

At the Gulf Coast lab yesterday, Franks showed about 75 samples of plankton containing perhaps a few bluefin larvae each.

Franks is also concerned about their next stage of life as juveniles. So little is known about these young voracious fish in the Gulf, he does not know if they tend to eat or swim in the oiled area.

“We observed oil in bluefin habitat,’’ he said. “We’re worried.’’

Beth Daley can be reached at bdaley@globe.com.