Mercury in Fish

It seems that health professionals are always telling us to eat more fish, but most people are aware that some species are too high in mercury, which causes damage to nerves and can lead to memory loss, irritability, and balance problems. 

In 1953, 121 individuals became ill from mercury poisoning in Matamata, Japan. Twenty-three of the sick were infants and a total of 46 people died. Survivors were left blind, deaf, and with coordination and intellectual deficits. The mercury was traced to contaminated fish in the bay where these individuals lived. Several plants in the area were discharging mercury-containing waste directly into the water that these people relied on for the fish that they ate every day. 

Mercury is highest in large predator fish, including tilefish, swordfish, king mackerel, marlin, shark, orange roughy, and bigeye tuna. Albacore tuna contains three times more mercury than canned light tuna.

Fish lowest in mercury include:

  • anchovies
  • Atlantic mackerel
  • catfish
  • cod
  • haddock
  • herring
  • Mahi-mahi
  • pollock
  • salmon
  • sardines
  • shrimp
  • sole
  • tilapia
  • trout
Women who are pregnant (or could become pregnant) ChildrenEveryone else
albacore tunaNoneNone if under 55 pounds3 oz per week
light tuna2 oz per week1 oz per week12 oz per week
shark, swordfish, king mackerel, and tilefish NoneNone6 oz per week

*Except for pregnant women and children, people can choose amongst three ounces of albacore tuna, 12 ounces of light tuna OR six ounces of the other fish each week.