It’s always been a mystery to me why the fishing industry equates “some fish have mercury, so avoid high-mercury fish” with “don’t eat any fish at all,!” Yet it does, arguing that those irresponsible scientists who issue warnings about mercury in fish will make people miss out on the heart and (for fetuses) cognitive benefits of fish.
Rather than join with scientists and government agencies to maximize the benefits of eating fish and minimize the risks by guiding us to low-mercury seafood, the industry has taken the low road: Deny the existence of any risk at all, attack and discredit those who disagree, try to intimidate the press by challenging every report that mentions risk.
A particularly extreme example has been the continuing coverage of actor Jeremy Piven, who in December got sick (exhaustion, memory, loss balance problems) from the high levels of mercury he developed, apparently as a result of eating a lot of tuna sushi, and withdrew from the Broadway play . His physician said Piven’s blood mercury level was 60 parts per billion (ppb), which is more than 10 times the EPA “reference level,” and his symptoms were similar to those in other people who eat a lot of the wrong kind of fish. His symptoms and his blood mercury level fit the diagnosis. Yet the press was full of credulous interviews with industry-friendly doctor who insisted, “It’s almost impossible to get mercury poisoning from eating fish.”
In fact it’s not hard at all. A 6-ounce swordfish steak contains about 130 µg of mercury, or 16 days’ worth of the Environmental Protection Agency’s reference dose for an adult man. A 5.5-ounce can of albacore tuna contains 55 µg, a full week’s dose for an adult man. Even canned light tuna, touted as a “low-mercury” fish by the industry (and the FDA, after intense industry lobbying), has 18 µg of mercury in a 5.5 ounce can. For someone like Piven, who eats fish twice a day, those µg’s can add up fast, and it’s easy to get a mercury dose far above the reference dose.
As a public service, let me then make the obvious point. If you eat a lot of fish—which in America, means more than twice a week—you should know what fish to choose to minimize your mercury exposure. The more fish you eat, the more often you should choose from the low-mercury list. Here’s a list of fish and seafood, sorted by mercury content, based on data from the U.S. Food and Drug Administration:
Contain less than 0.05 part per million (ppm) mercury. Can safely be eaten daily, or more often, without risk of exceeding reference dose: salmon, tilapia, ocean perch, whiting, pollock, hake, flounder, sole, , haddock, sardines, herring, anchovies, catfish, Atlantic mackerel, shrimp, clams, oysters, crayfish, scallops.
Contain between 0.05 and 0.20 ppm mercury. Can be eaten once or twice a week as long as other choices are from the low-mercury group. American shad, cod, whitefish, Atlantic croaker, freshwater trout, Pacific mackerel, canned “light” tuna, skate, freshwater perch, monkfish, mahi-mahi, snapper, blue crab, king crab, snow crab, squid, spiny lobster.
Contain between 0.21 and 0.50 ppm mercury. Should be eaten only in limited amounts (less than once a week) if you eat fish often: Canned albacore tuna, tuna steak, sea bass, Chilean sea bass, halibut, sablefish, sea trout, Pacific croaker, bluefish, Spanish mackerel, grouper, marlin, orange roughy, American lobster.
Contain more than 0.50 ppm mercury. Should be avoided by people who eat a lot of fish and by women of childbearing age: swordfish, shark, tilefish, king mackerel.