High-mercury fish species identified by FDA data

Certain types of fish contain high levels of methylmercury, which can negatively impact human brain and kidney health if consumed frequently. While seafood is generally a healthy source of omega-3 fatty acids and protein, mercury enters the aquatic environment through natural phenomena like volcanoes and forest fires, as well as human activities such as burning coal, oil, and wood.

According to data cited from the U.S. Food and Drug Administration (FDA), the seven fish species with the highest mercury content include king mackerel, swordfish, Gulf of Mexico grouper, shark, marlin, orange roughy, and bigeye tuna.

Mercury levels can vary significantly even within the same species or region. For example, king mackerel has the highest levels, whereas Spanish mackerel is considered medium and Boston mackerel is low. Similarly, bigeye tuna has high mercury levels, while skipjack tuna, commonly used in canned products, is considered low. Regional differences also exist, such as grouper from the Gulf of Mexico having higher mercury levels than grouper from the Atlantic Ocean.