The content of mercury in The Atlantic bluefin tuna appears to have decreased.

CC0 Public Domain
The Atlantic bluefin is native to both the western and the eastern Atlantic Ocean, as well as the Mediterranean Sea but now extinct in the Black Sea. It may exceed 450 kilograms (990 lb) in weight.

This is the conclusion made by US scientists who have analyzed tissue samples from tuna caught between 2004 and 2012 in the Atlantic Ocean off North America.

The researchers believe that the lower levels of mercury in the fish probably reflects reductions made of both usage and the release of mercury in North America.

As industry cuts down on its mercury emissions in North America, emissions are increasing in Asia, mainly due to coal burning.

The scientist now wants to investigate if mercury is decreasing in other tuna species as well.

The study has been published in Environmental Science & Technology.

Reference:

Cheng Shiuan Lee et al. Declining Mercury Concentrations in Bluefin Tuna Reflect Reduced Emissions to the North Atlantic Ocean. Environmental Science & Technology 14 November 2016. DOI: 10.1021 / acs.est.6b04328