A decrease in the mercury content in Atlantic bluefin tuna mirrors a fall in North American coal emissions, says new study by Stony Brook University in New York. Angela Moore reports.
STORY: If you like sushi you might be pleased to know that Atlantic bluefin tuna - one of the most sought after fish for the entree - has become a bit safer to eat. Researchers at New York's Stony Brook University noticed a decline in the mercury levels found in Atlantic bluefin tuna. They analyzed about 13-hundred of the fish over an eight year period in the Gulf of Maine. SOUNDBITE (English) NICHOLAS FISHER, STONY BROOK UNIVERSITY PROFESSOR OF MARINE SCIENCE AT THE SCHOOL OF MARINE AND ATMOSPHERIC SCIENCES, SAYING: "We saw that the concentrations of mercury in fish captured in 2012 were lower than the concentrations of similarly-sized fish captured in 2004 and likewise all the dates in between. So there was a pretty steady decline in the mercury concentration in these fish captured from 2004 to 2012." Researchers say the decline in mercury levels in the fish is very similar to the decline in use of coal-fired power plants in the U.S. SOUNDBITE (English) NICHOLAS FISHER, STONY BROOK UNIVERSITY PROFESSOR OF MARINE SCIENCE AT THE SCHOOL OF MARINE AND ATMOSPHERIC SCIENCES, SAYING: "The decline is only two percent per year, which doesn't sound that dramatic, frankly. But for ten straight years that becomes like a 20 percent decline. Two decades - it's a forty percent decline. So we're talking about some fairly significant declines. Even though the concentrations were still high, they did go down. What was curious as well is that the rate of decline in the bluefin tuna mercury concentrations parallel the decline in mercury emissions from North America, which declined at about that same rate over that same period of time. // So it seemed that the fish were responding almost in real time, which was kind of a surprise, responding to these declines in loadings of mercury from the power plant emissions." The scientists stress the link between mercury and coal emissions remains unproven. SOUNDBITE (English) NICHOLAS FISHER, STONY BROOK UNIVERSITY PROFESSOR OF MARINE SCIENCE AT THE SCHOOL OF MARINE AND ATMOSPHERIC SCIENCES, SAYING: "We don't know that. We just see a striking coincidence that the decline in emissions was almost identical to the decline in the mercury concentration in the tuna." SOUNDBITE (English) DANIEL MADIGAN, FORMER POSTDOCTORAL RESEARCHER AT STONY BROOK UNIVERSITY, SAYING: "Maybe one of the best things is that almost every time you look at something like this, it's getting much worse. So just to see that it's not getting worse at this point is pretty good news." While the information about coal and other fossil fuel emissions tends to offer only dire warnings for the environment - this is data that for once offers good news that is also easy to digest.