(HealthDay News) -- Mercury is found in many types of fish and shellfish. Because significant amounts of mercury can harm unborn babies and young children, women who are or may become pregnant, those who are nursing, and young children should avoid some kinds of seafood.

The U.S. Environmental Protection Agency offers these guidelines:

• Avoid eating fish that contain high levels of mercury, including swordfish, shark, king mackerel and tilefish.
• It's OK to eat up to 12 ounces per week of low-mercury fish and shellfish -- including shrimp, salmon, canned light tuna, pollock and catfish.
• Albacore tuna and tuna steak have more mercury than canned light tuna, so don't eat more than 6 ounces of albacore or tuna steak per week.
• Before you eat any fish caught locally, be aware of any advisories about the safety of local fish.