Source: Konrad Dabrowski

I've heard warnings about mercury in fish, so I started looking on labels and realized we usually eat farm-raised fish. Do they have problems with mercury too?

Good for you for eating fish. They're generally high in omega-3 fatty acids, which could reduce the risk of cancer and heart disease. Eating fish about twice a week is a good way to get plenty of omega-3 without going overboard.

By eating farm-raised fish, it appears you don't have to worry about mercury levels. A study published in the Journal of Food Science in 2001 analyzed farm-raised channel catfish, rainbow trout and red swamp crayfish for a number of heavy metals, including mercury, and found that they all were well below federal safety limits.

The study, conducted by Purdue University, found mercury levels averaged 40 to 100 times lower than the 1-part-per-million limit set by the Food and Drug Administration. The study was conducted over three years and tested fish from across the southern United States -- the nation's largest fish-farming region.

The news was a welcome relief for fish-lovers, who still should be cautious about eating too many fish caught in the wild. In fact, the Ohio Department of Health advises women of childbearing age and children under age 6 not to eat any fish caught in Ohio's lakes, rivers and streams more than once a week because of possible mercury contamination. In early 2001, the FDA issued a consumer advisory for the same groups against eating shark, swordfish, king mackerel and tilefish. These longer-lived, larger fish accumulate mercury over their lifetimes, which could damage a fetus' developing nervous system. And late in 2001, the Mobile (Ala.) Register uncovered high levels of mercury contamination in the Gulf of Mexico around oil and gas rigs, posing questions about the safety of fish caught in that area.

Every year, the Ohio Department of Health issues consumption advisories for fish caught in specific lakes, rivers and streams. The 2002 advisory is scheduled to be released in early March. Watch the ODH website, http://www.odh.state.oh.us/, for the latest word -- until then, keep enjoying that farm-raised fish.

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Editor: This column was reviewed by Konrad Dabrowski, aquaculture researcher in the School of Natural Resources at Ohio State University.