"Moderate, consistent evidence shows that health benefits derived from the consumption of a variety of cooked seafood in the U.S. in amounts recommended by the [2010 Dietary Guidelines for Americans, U.S. Department of Agriculture] Committee outweigh the risks," said Roger Clemens, Ph.D., CSO at Horn Company, Chatsworth, Calif., and adjunct professor at the University of Southern California School of Pharmacy. He recognized two, 3- to 5-ounce servings each week of such fish as salmon, oysters and rainbow trout, provide an average of 250 mg/day of n-3 fatty acids associated with the reduced risk of cardiovascular disease. "Consumers can safely eat at least 12 ounces of a variety of cooked seafood per week provided they pay attention to local seafood advisories and limit their intake of large, predatory fish like shark."

Toxicologists like Wallace Hayes, Ph.D., Harvard School of Public Health, said there is ongoing research to improve food safety especially for those predatory, saltwater fish like shark, tile, swordfish, and king mackerel that may carry a contamination many consumers are wary of.

"The bigger the fish, the more they've been around and the greater the potential for their level of mercury," said Hayes, recognizing studies that show varying amounts of methylmercury toxicity can impact the developing brain during the third trimester of pregnancy or through breast milk. Repeated low level exposure can also affect cardiovascular, endocrine, immune and cognitive aging systems.

Doris Hicks, seafood technology specialist with the Sea Grant Program, University of Delaware, Lewes, Del., worries consumers confused with the risks will prevent them from eating seafood weekly.

"Seafood is unique because there are measurable benefits and risks," said Hicks, explaining consumers must not only be aware of the source and quality of their seafood, but the handling practices, preparation and storage of seafood they may consume at home or in restaurants. "Most of the public recognizes the health advantages of seafood but over half have also heard something negative."

She has discovered many doctors and nurses are telling their patients to reduce their seafood consumption. In response, she worked with other food scientists to conduct online surveys and focus groups with healthcare professionals which ultimately led to the creation of an online educational resource for both health professionals and consumers, www.seafoodhealthfacts.org