Another reason not to eat bluefin ...

TuNo: Mercury in Bluefin Tuna Forces Search for Alternatives
ERICA BARNETT, 29 JAN 08
Recent lab tests, the New York Times reports, have found so much mercury in bluefin tuna--a popular item in sushi restaurants from coast to coast--that a diet of six pieces a week would exceed the maximum levels recommended by the US Environmental Protection Agency (EPA).
Owners of sushi restarants implicated in the study expressed astonishment at the findings, which also concluded that sushi from five of the 20 establisments tested could be shut down for exceeding acceptable mercury levels. Mercury levels included in the study were far greater than those found in canned tuna, which itself was the subject of a warning from the EPA and the federal Food and Drug Administration, who issued a statement in 2004 that children, pregnant women, and women who might become pregnant should avoid eating certain kinds of canned tuna. More recent studies have indicated that mercury may also cause health problems in adults, including neurological symptoms and cardiovascular disease.
Meanwhile, there are other (environmental) reasons to avoid bluefin tuna. As of last year (and for the next four years), Japan's annual quota for southern bluefin tuna has been cut in half, making it severely overfished, and its allotment of Atlantic bluefin has been reduced by almost 25 percent, because of shortages. The Washington Post reports that sushi restaurant proprietors are selling the fish at a substantial loss, and imports of tuna into the United States have dropped 24 percent, and last year, the US actually implored other nations to completely ban bluefin tuna fishing for three to five years until stocks can be replenished. Now the bluefin tuna population is threatened with extinction.

OK, that's the bad news. The good news is, there are alternatives! Several tuna purveyors deal in low-mercury, "safer" alternatives--chief among them Kona Kampachi tuna, AKA Kona Blue, a sustainably farmed fish which has, since at least last year, been catching the attention of sushi and other high-end chefs looking for sustainable alternatives to conventional farmed fish around the country. The fish receive no antibiotics or medications, and their food comes from sustainable wild fisheries and organic sources. Another alternative comes from Wild Planet, a sustainable seafood enterprise that produces "minimal" and "low" mercury tuna--meaning fish that average less than 0.15 parts per million of mercury, thanks in part to their small size when caught--between nine and 25 pounds, compared to the 70-plus-pound fish that are caught in traditional line fishing.

Much, much more information (and many more resources for those seeking non-mercury-contaminated alternatives to conventional bluefin tuna) can be found at the International Commission for the Conservation of Atlantic Tunas, which works to conserve tunas "and tuna-like species" in the Atlantic Ocean.