Mercury in Seafood

Mercury is a natural element that is found in very small quantities in air, water and all living things. Mercury can find its way into food in a number of ways including: natural recycling, volcanic activity, burning of fossil fuels, and pollution. There has been an increased concern about mercury in seafood over the last decade which has caused unwarranted alarm about all seafood and general confusion about what is safe to eat.

Although all fish have trace amounts of mercury, levels vary widely and most fish have very low amounts usually less than one tenth of the U.S. established guideline for the allowable level of mercury in fish and seafood products. Studies have shown that the highest levels of mercury are found in large fish such as sharks, swordfish, and large tunas such as bluefin. Smaller tunas such as skipjack which is used for canned light tuna have much less mercury. Canned white meat albacore tuna has intermediate levels of mercury.

Most of the popular species of fish and shellfish consumed in the U.S. have been shown to have low mercury levels. Seafood choices that are very low in mercury include: salmon, sardines, pollock, flounders, cod, tilapia, shrimp, oysters, clams, scallops and crab. There is good evidence that the benefits associated with the omega-3 fatty acids in these species and most types of seafood greatly outweigh the small risk associated with mercury for most people.

Tips to Manage Risk

The U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) have developed the following advice to help consumers minimize risks that could be associated with mercury in seafood. The advice is summarized below. To see FDA & EPA’s consumer brochure click here.

  • For most people, the risk from mercury by eating fish and shellfish is not a health concern.
  • Women who may become pregnant, pregnant women, nursing mothers, and young children should follow the 3 recommendations below for selecting and eating fish or shellfish to receive the nutritional benefits and be confident that they have reduced their exposure to the harmful effects of mercury.
    1. Do not eat Shark, Swordfish, King Mackerel, or Tilefish from the Gulf of Mexico because they contain high levels of mercury.
    2. Eat up to 12 ounces a week of a variety of fish and shellfish that are lower in mercury.
      • Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
      • Another commonly eaten fish, albacore (“white”) tuna has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to 6 ounces (one average meal) of albacore tuna per week.
    3. Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week. Advisories are available from local and state health departments, as well as the U.S. Environmental Protection Agency.