EWG’s Consumer Guide to Seafood

Find healthy seafood picks!

September 18, 2014

EWG’s Consumer Guide to Seafood: Executive Summary

Many Americans would benefit from eating more seafood. Children born to mothers who eat fish and shellfish that are rich in omega-3 fatty acids and low in mercury during pregnancy have better cognition and behavior than children born to mothers who skip fish altogether, according to some scientific tests. People at average or high risk for heart disease can lower their blood cholesterol levels and reduce the risk of heart attacks and strokes when they make seafood a routine part of their diets.

EWG investigated existing data amassed by government and independent scientific institutions on seafood contamination and omega-3s. We found that both the mercury and the omega-3 fatty acid levels in fish and seafood vary widely.  We concluded that the federal government’s advice to Americans to eat more fish and avoid a few high-mercury species is seriously flawed and must be improved.

EWG's Good Seafood Guide fills the gaps of the federal government’s flawed seafood guidance.  Our aim is a user-friendly summary that helps consumers decide which seafood to eat, which to approach with caution and which to avoid.


Helpful Information

Best Bets!

Very High Omega-3s, Low Mercury, Sustainable

  • Wild salmon
  • Sardines
  • Mussels
  • Rainbow trout
  • Atlantic mackerel
One or two four-ounce servings a week of these fish have little mercury and optimum levels of omega-3 fatty acids for pregnant or nursing women and people with heart disease.
Show Full Table

Good Choices

High Omega-3s, Low Mercury

  • Oysters
  • Anchovies
  • Pollock/Imitation crab
  • Herring
These species have favorable concentrations of omega-3 fats. One four-ounce serving provides at least 25 percent of the weekly recommended omega-3 consumption. A pregnant woman of average weight could eat three four-ounce servings per week without ingesting too much mercury. These species do not necessarily come from sustainable sources.


But Also Low Omega-3s

  • Shrimp
  • Catfish
  • Tilapia
  • Clams
  • Scallops
  • Pangasius (Basa, Swai, or Tra)
These varieties can be healthy sources of protein and other nutrients, but an adult would have to eat five to 20 four-ounce portions to meet the omega-3 recommendation for pregnant women and people with heart disease.

Risks Add Up

Pregnant Women And Children Should Limit Or Avoid

  • Canned light and albacore tuna
  • Halibut
  • Lobster
  • Mahi mahi
  • Sea bass
These fish contain too much mercury to be part of the regular diet of pregnant women and children. How much you can safely eat depends on your age, weight and health status. Use EWG's Seafood Calculator to gauge how often you can eat them and to find healthier options.


Mercury Levels Too High To Eat Regularly

  • Shark*
  • Swordfish*
  • Tilefish*
  • King mackerel*
  • Marlin**
  • Bluefin and bigeye tuna steaks or sushi**
  • Orange roughy**
High-mercury seafood should never be eaten by pregnant women and children, according to EWG's analysis and federal government warnings. Everyone else should eat these species infrequently or not at all.

*FDA/EPA advisories recommend that pregnant women and children never eat these species.

** EWG analysis concludes these species are high in mercury.



Because the amount of mercury you can safely consume depends on your pregnancy status and weight, EWG’s Seafood Calculator will give you personalized advice for more than 80 species of commercial fish and shellfish.

Consumers who read the proposed new seafood guidance by the federal Food and Drug Administration and Environmental Protection Agency will find references to omega-3 fatty acids buried in the agencies’ announcement, and omega-3s aren’t mentioned at all in a PDF summary linked to the announcement page.  The lack of emphasis on omega-3s is striking, because these beneficial fatty acids are one of the main reasons the government is encouraging people to eat more fish.

Consumers who scroll deep into the announcement page will see a table of commonly eaten fish and their associated omega-3 and mercury levels, but they will find it very difficult to determine from this table how much of various fish varieties they must eat per week to get the recommended amount of omega-3s.  Nor can they tell how much of each variety they can eat per week without consuming too much mercury.

As EWG’s January 2014 report cautioned, not everyone who follows federal government dietary guidelines and eats two or three fish meals per week will achieve the intended health benefits:  some people could consume too much mercury, and others, too few omega-3s (EWG 2014). Eight of the 10 seafood species most popular in the American diet are very low in omega-3s. Other popular choices, like canned albacore tuna, swordfish and some types of sushi, pose a significant mercury risk if pregnant women or children eat them frequently.

EWG believes that the federal government’s proposed seafood guidance is flawed for another reason:  it relies on a “safe” level established by the EPA in 2001.   Some prominent scientists now consider that level too high to protect the developing fetus and young children.  (Some evidence suggests that omega-3s in seafood could offset the deleterious effects of mercury to an extent.)

The EPA has launched a multi-year process to revise its assessment of mercury toxicity. EWG believes the agency should tighten its safe level to account for recent scientific studies that have found that children’s intellectual abilities suffer, even at trace exposure to mercury.