Office of Environmental Health Hazard Assessment

FISH

MERCURY IN FISH
INFORMATION FOR PEOPLE WHO EAT FISH
[03/12/14]

[download this fact sheet as pdf]

What Is Mercury?

  • Mercury is a natural element found in rocks, coal, and soil.
  • Mercury is released into air when soil and rocks decay or volcanoes erupt.
    • Human activities—such as burning coal and the use of mercury to mine gold—also add mercury to the environment.
  • Mercury in the air falls back down in rain and snow and runs off into rivers, lakes and other bodies of water, especially during storms.

How does mercury get in fish?

  • Mercury passes into tiny plants and animals living in water and then into the fish that eat them.
  • When big fish eat the small fish, the levels of mercury build up in the big fish.

What is the concern?

  • Mercury can harm our health if we get too much of it in our bodies.
  • Eating fish is the main way that mercury gets into people.
    • Follow OEHHA's advisories to enjoy the benefits of eating fish with less mercury than other fish.

Which fish have the most mercury?

  • Mercury is found in most freshwater and saltwater fish.
  • Larger, older fish tend to have more mercury than younger fish.
  • Fish that eat other fish have the most mercury.
    • In the ocean, these include sharks and swordfish.
    • In lakes and rivers, bass generally have the highest levels of mercury.

What are the health effects of eating high-mercury fish?

  • Mercury found in fish can damage the brain while it is growing.
  • Pregnant mothers' unborn babies and children are most sensitive.
    • Too much mercury may affect their behavior and how they learn.
    • Mothers can pass mercury to their babies during pregnancy.
    • Women in their childbearing years (18–45 years) should be most careful to choose fish wisely.

Should I Eat Fish and Serve Fish to My Family?

  • Yes, fish are very important in the diet.
    • They provide protein and important fats called "omega-3 fatty acids" that are good for your heart and your child's brain as it grows.
  • Choose fish wisely. You can enjoy the benefits from eating fish if you eat fish that are low in mercury.

DO YOU EAT FISH THAT YOU, FRIENDS, OR FAMILY CATCH?

  • Follow OEHHA's advice for fish caught from local water bodies:
    • www.oehha.ca.gov/fish.html
      • Or contact OEHHA at (916) 327-7319 or (510) 622-3170.
    • www.dfg.ca.gov/regulations
      • Or look in the California Department of Fish and Wildlife Sport Fishing Regulations booklets (Freshwater and Ocean).
  • If you fish at lakes or reservoirs that do not have an OEHHA advisory, follow OEHHA's general statewide advice below.

GUIDELINES FOR EATING FISH FROM CALIFORNIA LAKES AND RESERVOIRS WITHOUT SITE-SPECIFIC ADVICE

  • Women 18-45 and children:
    • Can safely eat two servings per week of rainbow trout, or
    • Can safely eat one serving per week of bullhead, catfish, bluegill, or small brown trout (16 inches or shorter).
    • Should avoid eating bass, carp, or large brown trout.
  • Women over 45 and men:
    • Can safely eat up to six servings per week of rainbow trout, or
    • Can safely eat up to two servings per week of bullhead, catfish, bluegill, or small brown trout (16 inches or shorter), or
    • Should eat no more than one serving per week of bass, carp, or large brown trout.

What else can I do?

  • Fish in a variety of places in case the spot where you usually fish is more contaminated.
  • Eat a mix of different kinds of fish and shellfish.
  • Choose fish and shellfish that are lower in mercury such as salmon, trout, tilapia, cod, sole, sardines, shrimp, oysters, and other shellfish.
  • For the most health benefits, choose fatty fish such as salmon, trout, herring, chub mackerel, and sardines.
    • These fish have healthy omega-3 fatty acids.
  • Eat only the fillet or "meat" of the fish.
    • Other chemicals can be found in the organs of fish. Do not eat these parts.

ADVICE FOR WOMEN 1845 YEARS AND CHILDREN FOR FISH FROM STORES AND RESTAURANTS

The U.S. Environmental Protection Agency and U.S. Food and Drug Administration recommend that women who are pregnant or might become pregnant, nursing mothers, and young children:

  • Do not eat shark, swordfish, king mackerel, or tilefish
  • Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish species that are lower in mercury, such as shrimp, canned light tuna, salmon, pollock, and (farmed) catfish.
  • You may eat up to 6 ounces of canned albacore ("white") tuna per week. Canned albacore tuna has more mercury than canned light tuna, but it also has more omega-3 fatty acids.

ALL OTHER ADULTS

Remember: Fish are an important part of a healthy diet. The American Heart Association recommends eating fish at least twice a week. For the most health benefits, choose fatty fish such as salmon, trout, herring, chub mackerel, and sardines. These fish are also lower in mercury.

You can find a guide for eating fish you buy at: http://www.oehha.ca.gov/fish/fishbuyersguide.html

A more technical description of mercury in fish is available here as a pdf file

Additional information and documents related to fish advisories are available on the OEHHA Web Site at http://www.oehha.ca.gov/fish.html. County departments of environmental health may have more information on specific fishing areas.

 

 
 
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