According to a study published in the journal
Nature, increase in sea temperatures and overfishing impacts the level of methylmercury
in fish. Methylmercury concentration in fish has increased despite its decrease
in seawater since 1990s
The study observed there has been up to 23%
increase in methylmercury concentration in Atlantic cod fish in the
northwestern Atlantic Ocean. The increase has been due to changes in diet
caused by overfishing. As a result of diet change, cod fish relied more on
larger herring and lobster, which have higher concentrations of methylmercury.
The study further noted that ocean warming causes
changes in the methylmercury accumulation in fish. This is because fish
metabolism is temperature dependent.
The Gulf of Maine is one of the fastest warming
bodies of water in the world. The researchers found that between 2012 and 2017,
methylmercury levels in Atlantic Bluefin tuna increased by 3.5% per year
despite decreasing emissions of mercury.
Methylmercury is a harmful neurotoxicant. It
causes central nervous system (brain and spinal cord) damage.