The National Marine Fisheries Service estimates Americans ate about 16.3 pounds of fish and shellfish/person last year. Although many people shop for fish at their local fish market or grocery store, many enjoy catching their own fish. Every year, more than 12 million people in the U.S. fish in the ocean or along the coastlines. In 2007 alone the National Oceanic and Atmospheric Administration reports recreational fisherman caught more than 468 million fish. Some of the most popular varieties are spotted trout, lane snapper, striped bass, Atlantic croaker, chub mackerel, black rockfish and bigeye scad.

Health experts recommend eating fish at least two times a week. Fish is a good source of protein and is low in saturated fat. Certain kinds of fatty fish, like salmon, tuna, trout, mackerel, herring and sardines, contain high levels of omega-3 fatty acids, healthy fats that may lower cholesterol levels and protect against heart disease.

Fish Concerns

Several years ago, researchers discovered that many species of fish have high levels of mercury. Although mercury occurs naturally in the environment, a major source is industrial pollution. When it falls in the water, mercury turns into methylmercury, a contaminant that can harm the developing nervous system of a fetus. Fish absorb methylmercury from the water and the contaminant accumulates in their bodies. Because of the potential danger to an unborn baby and young child, health experts recommend pregnant women avoid eating shark, swordfish, king mackerel, tilefish and albacore tuna (canned light tuna is considered safe).

Recently, experts from the University of Pittsburgh Center for Healthy Environments and Communities, tested fish caught from the Three Rivers area (where the Allegheny, Monongahela and Ohio Rivers converge). Some of the fish contained high amounts of pharmaceutical estrogen, closely approaching levels associated with cell proliferation. Male fish with high estrogen levels had abnormal sex characteristics. The researchers also found high levels mercury, selenium and arsenic.

Researcher, Conrad Volz, Dr.P.H., says high levels of estrogens and other contaminants don’t naturally occur in river waters. The estrogen most likely came from overflow and discharge from nearby sewer treatment plants. Mercury, selenium and arsenic are attributed to emissions from coal-fired power plants.

When contaminants enter the water, they can be absorbed into the fish through their gills. In addition, high levels of many contaminants are found in river sediment. Bottom feeding fish take in more of the pollutants as they eat. Contaminants are stored in the fish’s fatty tissue and can accumulate over time. Smaller fish are eaten by other fish and the cycle continues up the food chain, until the fish reaches the table for human consumption.

Volz says people shouldn’t stop eating fish because it’s a part of a healthy diet. However, he recommends consumers avoid fishing or buying fish caught from areas where contamination levels are high. The EPA monitors water quality of lakes, rivers and coastal areas and issues “fish advisories” when levels of contaminants are found to be unsafe. Consumers who are purchasing fish should ask where the catch originated.

The EPA recommends avoiding bottom feeding fish, like catfish and carp, because they are more likely to have taken up higher levels of contaminants as they feed. People who prefer the popular game fish, like lake trout, salmon, walleye and bass, should eat the younger, smaller-sized fish because they will not likely have accumulated as many contaminants as older, larger fish of the same species.

Volz also cautions that, like a canary in a coal-mine, fish serve as a warning indicator for potential dangers of pollutants and contaminants in the water. In addition to controlling industrial pollution, people must stop disposing chemicals and drugs down the toilets, where they end up in sewage treatment plants. Currently, there is no way to remove these chemicals from the waste and they can find their way into the ground through overflows or into the water through discharge of treated sewage.

Pollution affects more than the fish. On September 12, the Associated Press reported at least 46 million Americans may be affected by drinking water contaminated with one or more common pharmaceuticals, like hormones, anti-seizure compounds, tranquilizers and cholesterol medications.

For information on water quality and fish safety:

Environmental Protection Agency

Food and Drug Administration

NOAA, Office of Sustainable Fisheries