Mercury levels in Hawaiian yellowfin tuna increasing

http://www.eurekalert.org/pub_releases/2015-01/uom-mli012815.php

Public Release: 29-Jan-2015
University of Michigan

Mercury concentrations in Hawaiian yellowfin tuna are increasing at a rate of 3.8 percent or more per year, according to a new University of Michigan-led study that suggests rising atmospheric levels of the toxin are to blame.

Mercury is a potent toxin that can accumulate to high concentrations in fish, posing a health risk to people who eat large, predatory marine fish such as swordfish and tuna. In the open ocean, the principal source of mercury is atmospheric deposition from human activities, especially emissions from coal-fired power plants and artisanal gold mining.

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By compiling and re-analyzing three previously published reports on yellowfin tuna caught near Hawaii, U-M's Paul Drevnick and two colleagues found that the concentration of mercury in that species increased at least 3.8 percent per year from 1998 to 2008.

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Yellowfin tuna, often marketed as ahi, is widely used in raw fish dishes--especially sashimi--or for grilling. The Natural Resources Defense Council's guide to mercury in sushi lists yellowfin tuna as a "high mercury" species.