February 7, 2001

2 min read

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Farm-raised Fish Come Clean

By Kate Wong

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Amid concerns that certain offshore fish contain high levels of heavy metals such as mercury, a study published in the February Journal of Food Science indicates that farm-raised fish are safe. Over a three-year period, Charles Santerre of Purdue University and his colleagues tested metal levels in catfish, trout and crawfish grown in aquaculture facilities across the southern U.S. Levels of mercury in these fish measured on average 40 to 100 times lower than the one-part-per-million limit set by the Food and Drug Administration. Similarly, the team reported very low levels of 34 pesticides in the same fish last year.

Catfish is the leading commercially grown fish in the U.S., accounting for 70 percent of total fish production in 1998-99. Trout represents about 10 percent of domestic aquaculture output. "Since virtually all catfish and trout purchased from grocery stores and at restaurants are farm-raised," Santerre notes, "consumers should continue to enjoy these products and benefit from their nutritional value." He warns, however, that fish caught from local rivers, streams and lakes in many states have been found to contain high levels of mercury and other harmful contaminants¿something anglers should take note of, particularly when it comes to children, who are particularly sensitive to such pollutants.

"It is also important that we protect the unborn child," Santerre observes. "This is that stage of life where contaminants may have the greatest impact on the health and development of the child. Residues of some pollutants, like PCB, may be stored in a woman's body for longer than six years and then get passed to her children through the placenta and breast milk. I worry that anglers with good intentions may bring contaminated fish home to feed to their family."

Kate Wong is an award-winning science writer and senior editor for features at Scientific American, where she has focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for nearly 30 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home to the shores of Kenya’s Lake Turkana in search of the oldest stone tools in the world, as well as to Madagascar on an expedition to unearth ancient mammals and dinosaurs, the icy waters of Antarctica, where humpback whales feast on krill, and a “Big Day” race around the state of Connecticut to find as many bird species as possible in 24 hours. Wong is co-author, with Donald Johanson, of Lucy’s Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow her on Bluesky @katewong.bsky.social

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