Do not eat fish or seafood that is high in mercury, if you are pregnant, lactating, or thinking of becoming pregnant. (Your body needs up to 6 months to get rid of mercury you may have consumed.) The worst are Shark, Swordfish, King Mackerel, or Tilefish. These should not be eaten.
Concerning tuna, it is safest to eat canned light tuna. Albacore or "white" tuna has more mercury than canned light tuna. If you eat albacore tuna, limit yourself to 6 ounces (one average meal) of albacore tuna per week. Note: Some Sushi is tuna.
Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish you catch from local waters, but don't consume any other fish during that week.
Don't avoid all fish and seafood, These provide you and your baby with the omega-3 fatty acids that are beneficial to the development of your baby's brain and cardiovascular system. Eat fish/seafood low in mercury, such as schrimp, light.