If you want to gain the health benefits of fish, the experts recommend eating at least three servings a week. But what about the risk of mercury and other toxins contained in some kinds of seafood?

You shouldn’t worry if you avoid eating fish with high levels of pollutants, because the benefits far outweigh the risks, according to a group of researchers at Umea University in Sweden who reported their findings recently after years of weighing the risks of mercury content against the advantages of healthful fatty acids.

Seafood contaminants include metals (such as mercury, which affects brain function and development), industrial chemicals (PCBs and dioxins) and pesticides (DDT). These toxins are most often found on land and make their way into the ocean food chain through the smallest plants and animals. Then, as the smaller species are consumed by larger ones, these pollutants are concentrated. That’s why large predatory fish, like shark and swordfish, end up with the most toxins.

We can minimize the risks by making smart seafood choices. One of the best resources for information is the Monterey Bay Aquarium’s Seafood Watch program, which has identified seafood that is "Super Green," meaning that it is good for human health and does not harm the oceans. The Super Green list highlights products that are currently on the Seafood Watch "Best Choices" (green) list, are low in environmental contaminants and are good sources of long-chain omega-3 fatty acids.

As an example, take canned tuna – one of the most popular fish consumed in the United States. Media reports have caused much confusion about the safety of eating canned tuna due to varying levels of mercury. Here’s what Environmental Defense, a partner organization with Seafood Watch, has to say on the subject:

The two most popular types of canned tuna – white and light – vary greatly in their average mercury content. Overall, it’s best to exercise caution in how much tuna you (or especially your children) consume.

  • Canned white tuna consists of albacore, a large species of tuna that accumulates moderate amounts of mercury, but it also contains high levels of heart-healthy omega-3 fats. Therefore, Environmental Defense recommends that both adults and children limit their consumption of canned white tuna.
  • Canned light tuna usually consists of skipjack, a smaller species with approximately one-third the mercury levels of albacore. Therefore, it is generally recommended only that young children (ages 0-6) limit their consumption of canned light tuna.

The following fish varieties constitute the healthy “Super Green List”:

  • Albacore Tuna (troll- or pole-caught, from the U.S. or British Columbia)
  • Freshwater Coho Salmon (farmed in tank systems, from the U.S.)
  • Oysters (farmed)
  • Pacific Sardines (wild-caught)
  • Rainbow Trout (farmed)
  • Salmon (wild-caught, from Alaska)


Other Healthy "Best Choices" include:

  • Arctic Char (farmed)
  • Barramundi (farmed, from the U.S.)
  • Dungeness Crab (wild-caught, from California, Oregon or Washington)
  • Longfin Squid (wild-caught, from the U.S. Atlantic)
  • Mussels (farmed)

Do you have a favorite recipe for a fish from the “Super Green List”?


Science Daily
Monterey Bay Seafood Watch
Environmental Defense