December 5th, 2016 — There’s some good news for sushi lovers. A new report finds that over an 8-year period, mercury levels in Gulf of Maine tuna declined 2 percent a year — a decline that parallels reductions in mercury pollution from Midwest coal-fired power plants.
Two years ago, Dr. Nicholas Fisher, a professor of marine sciences at Stony Brook University in New York, had a bit of luck — he found out that a colleague had established a collection of 1,300 western Atlantic bluefin taken from the Gulf of Maine between 2004 and 2012.
“They were frozen, wasn’t the entire fish, just about a pound from each fish or so. And then my colleagues and I in New York dissected out muscle tissue from each sample and analyzed it to determine the mercury content of each fish,” he says.
And as they created a timeline for mercury content for each year, taking into account the age and size of each fish sampled, a clear picture emerged.
“There was a fairly steady decline for all ages of fish, and the decline rate was approximately 2 percent per year, which doesn’t sound all that dramatic, but over 10 years it’s about 20 percent. Over two decades its about 40 percent,” Fisher says.