List of Fish High in Mercury

by Kat Long


The U.S. Food and Drug Administration considers species with a mercury level of .5 parts per million to be potentially harmful. Consuming too much mercury -- especially during pregnancy or in early childhood -- can cause prenatal physical and mental disabilities and developmental disabilities in children under 6. Environmental groups recommend avoiding fish high in mercury to avoid negative health effects and to save marine ecosystems from destructive commercial fishing methods.

King Mackerel

A fast-swimming, streamlined fish, king mackerel migrates along the western Atlantic seaboard and the Gulf of Mexico, luring commercial and sport anglers who are looking for a spirited fight. The Monterey Bay Aquarium's 2009 report "Turning the Tide: The State of Seafood" recommends that consumers avoid eating large predatory fish whose diets consist of other potentially mercury-contaminated fish; king mackerel is one to avoid for that reason.


A popular sportfish due to its extreme speed, average length between 15 and 20 feet and habit of leaping into the air when hooked, marlin species are top-of-the-food-chain fish. Besides being high in mercury, marlin suffer from overfishing and often end up as bycatch—accidentally killed species—in commercial longline fishing for tuna and swordfish. Five species of marlin appear on Greenpeace International's Seafood Red List of species harvested from unsustainable fisheries.

Orange Roughy

A deep-sea fish found in the Atlantic Ocean, orange roughy live an extraordinarily long time—more than 100 years on average—and absorb mercury for decades from the fish they eat. Orange roughy also reproduce at slow rates, making them vulnerable to overfishing.


Another alpha fish, sharks are feared marine predators that often consume a high-mercury diet. Greenpeace estimates that 100 million sharks are killed annually from commercial fishing, illegal fishing and longlines meant for other species. In fact, the Monterey Bay Aquarium reports that interactions with fishing gear are the primary cause of diminishing populations of endangered sharks.


A large migratory, predatory fish with a spearlike bill, swordfish exhibit high levels of mercury. While U.S. law prohibits catching swordfish by environmentally destructive longlines, other nations continue to do so, especially in the Pacific. If you must eat swordfish, the Natural Resources Defense Council recommends U.S.-caught species harvested by harpoon or handline if possible.


Like orange roughy, blueline and golden tilefish are long-lived species that inhabit deep waters. They accumulate mercury in their tissues over long periods and, as nonmigrating fish, are easy prey for commercial fishing. Avoid blueline tilefish and golden tilefish caught in the Gulf of Mexico and south Atlantic. A good alternative is wild-caught golden tilefish from the U.S. mid-Atlantic.

Bigeye Tuna

Often sold under its Hawaiian name Ahi, bigeye tune is a popular sushi and sashimi fish. The Environmental Health Fund considers bigeye tuna caught with longlines high in mercury, while bigeyes fished using trolls or pole-and-line gear are younger with lower accumulations of mercury.

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This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or