Nutritionists agree that fish is an important dietary source of long-chain omega-3 fatty acids; however, many pollutants in the basin may cause nervous system disorders and long-lasting health effects in fetal and childhood development. For adults, exposure to mercury is primarily through consumption of commercial or sportfish. For the fetus and infant, exposure may come primarily from the mother through placental transfer or breast milk.
Fish consumption advisories, generated by health departments, are designed to protect sensitive populations from excessive exposure to these pollutants in sport fish. The U.S. EPA and FDA announced in 2004, a joint consumer advisory on methylmercury in fish and shellfish to reduce the exposure to high levels of mercury in women who may become pregnant, pregnant women, nursing mothers, and young children.
Some anglers in ethnic groups, because of culture or because of necessity, rely on fishing to supply an important part of their families' diets. Although research has clearly shown that high levels of contaminants can exist in some fish in Lake Michigan (methylmercury commonly found in Lake Michigan fish is seven million times greater than the surrounding waters) [U.S. EPA, 1999], these groups consume large quantities of fish without regard to minimizing the risk of contamination. Fish advisories have had little effect on their fish consumption behavior.