Learn more about mercury and its effects at the Natural Resources Defense Council web site here:
PROTECT YOURSELF AND YOUR FAMILY
Consumer Guide to Mercury in Fish
The list below shows the amount of various types of fish that a woman who is pregnant or planning to become pregnant can safely eat, according to the Environmental Protection Agency (EPA). The EPA recommendation is based on body weight and is, therefore, dependent on a person's size. The guidance below is based on a 6 oz serving of cooked fish for a 130lb/60kg woman. People with small children who want to use the list as a guide should reduce portion sizes. Adult men, and women who are not planning to become pregnant, are less at risk from mercury exposure but may wish to refer to the list for low-mercury choices. For a more personalized recommendation, use NRDC's mercury calculator.
Protecting yourself -- and the fish: Certain fish, even some that are low in mercury, make poor choices for other reasons, most often because they have been fished so extensively that their numbers are perilously low. These fish are marked with an asterisk (read more below).
Eat less than four servings per month:
Mackerel (Spanish, Gulf)
Sea Bass (Chilean)
Tuna (Canned Albacore)
Tuna (Bigeye, Ahi)
* High mercury: From 0.3 to 0.49 parts per million
** Highest mercury: More than .5 parts per million