Sea sure: Know which fish to order to protect your health, and the seven seas.

RODALE NEWS, EMMAUS, PA—Fish sticks aren’t the only aquatic food choice that’s questionable for your health. It’s true that some varieties of fish contain an especially beneficial type of fat, called omega-3 fatty acids, which help to lower blood pressure, heart rate, and other risk factors associated with heart disease. But fish may also contain mercury and other contaminants, such as dioxins and polychlorinated biphenyls (PCBs).

THE DETAILS: According to the Journal of the American Medical Association, mercury (which fish absorb from water, suspended sediments, and their food) may affect the developing nervous systems of unborn babies and infants. Shark, swordfish, king mackerel, and golden bass all contain more mercury than other varieties. As for dioxins and PCBs, they accumulate in fish in much the same manner as mercury, and the U.S. Environmental Protection Agency (EPA) categorizes them as likely human carcinogens. Also worth considering: the environmental impact of the fish you buy. Some fishing techniques deplete the stock of not only target fish but of other species caught incidentally. Some fish farms pollute the environment, or allow the farmed fish to escape into the wild and upsetting a delicate ecological balance.