Toxic Farmed Salmon: Arctic Science Journeys Radio

Radio Script
2004

SUSPECT SALMON: Scientists say farmed salmon contain significantly higher levels of dangerous chemicals than do wild salmon, and may be unhealthy to eat. (Courtesy BBC)

Toxic Farmed Salmon
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INTRO: Health officials have consistently said a diet that includes fish such as salmon lowers the chance of heart disease and other ailments. And while that advice remains true today, scientists who just completed a study of contaminants in the world's salmon supply say not all salmon are safe to eat. Doug Schneider has more in this week's Arctic Science Journeys Radio.

STORY: It took only about two decades for countries like Chile and Norway to produce more farmed salmon than fishermen harvest from the wild. But it may have taken just a study published this month in the journal Science to make people put the brakes on eating farmed salmon.

In the study, scientists say levels of contaminants such as PCBs, dioxin, dieldrin, and toxaphene were significantly higher in farmed salmon than in their wild counterparts.

Jeffery Foran is president of the Wisconsin-based organization, Citizens for a Better Environment, a group that participated in the study.


Farmed vs. wild: Concentrations of selected contaminants in farmed, supermarket and wild salmon. Red represents farmed salmon, green represents wild salmon, and yellow represents salmon purchased at supermarkets. (Courtesy of Science and study authors.) Click image to view larger version.

FORAN: "As our study shows, there were indeed significant differences in contaminant levels between farmed salmon and wild salmon, with the farmed salmon having up to ten times higher contaminants than the wild salmon."

Foran and scientists from Indiana University, the University at Albany, and Cornell University measured PCBs and 49 other toxic contaminants in 700 samples of farmed and wild salmon purchased from supermarkets in major cities around the world.

Their analysis found that salmon from European farms had significantly higher levels of contaminants than did salmon from farms in North and South America. However, while Chile and Washington State had the lowest levels of contaminants in their farmed salmon, the levels were still substantially higher than those found in wild salmon. Likewise, farmed salmon sold in European supermarkets had higher concentrations of contaminants than farmed salmon sold in U.S. food stores.

The levels of contaminants in all salmon were still below standards set by the U.S. Food and Drug Administration. But Foran points out that the FDA lacks standards for most of the compounds researchers measured, and the agency doesn't consider the effects of exposure to multiple chemicals simultaneously. That, says Foran, is reason enough to warn people away from farmed salmon, despite the well-documented health benefits from nutrients such as omega-3 fatty acids.

FORAN: "This is the first time that I'm aware of that a study has come forward and said there appears to be a trade-off. And that is that in these farmed salmon you can get these healthy fatty acids and oils, but at the same time you're getting a dose of unhealthy contaminants."

That isn't to say people should stop eating salmon entirely. As the study discovered, wild salmon caught in waters off Alaska and Canada had very low levels of pollutants. Jeffery Foran suggests consumers eat only wild salmon, or other fish, at least for now.

FORAN: "We are not telling people not to eat salmon. This is not a problem with salmon. This is a problem with farmed salmon. There are immense health benefits associated with eating fish that have high levels of omega-3 fatty acids—the good fatty acids that fight heart disease and do all kinds of other wonderful things for you. You can get those fatty acids from wild salmon, just as you could from the farmed salmon. But at the same time, by eating wild salmon you're not getting that dose of contaminants, as opposed to eating farmed salmon."

Farmed salmon from Chile, Norway, Iceland, Scotland, Canada, the United States and elsewhere today account for more than half the salmon sold worldwide. Each year, these farms raise many millions of salmon inside huge pens anchored in ocean fjords and bays. The problem, says Foran, isn't that salmon are raised on farms. The problem is that these salmon are fed a steady diet of feed pellets, themselves laced with high levels of pollutants.

FORAN: "We did identify through analysis the fish feed, the feed that's provided to the farmed salmon, as the source of at least a significant component and probably most of the contaminants in the farmed fish. The feed is made up of ground fish meal taken from the small fish, the forage fish, that live in the ocean. So these fish are fed a super-sized dose of contaminants in the fish they eat."

The farmed salmon industry has been criticized in recent years for its production and environmental practices. And while studies on contaminants in farmed salmon have been done before, the results were largely inconclusive. This study, funded by the Pew Charitable Trusts' environment program, marks the first time researchers have looked at the issue in detail.

In the long-term, the world's salmon farming industry plans to fix the contaminant problem. New feeds that use vegetable oils and soy proteins will help, they say, as will new technologies that remove contaminants from the feed. But in the short-term, it's anyone's guess how the farmed salmon industry will weather this latest assault on their products.

OUTRO: This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. I'm Doug Schneider.

Audio version and related websites (above right)

Thanks to the following individuals for help preparing this script:

Jeffery A. Foran
President
Citizens for a Better Environment
1845 N. Farwell Ave., Suite 220
Milwaukee, Wisconsin 53202
Phone: 414-963-9299
Email: Jforan@wi.rr.com
Web: http://www.cbemw.org/

Ronald A. Hites
School of Public and Environmental Affairs
Indiana University
Bloomington, Indiana 47405
Phone: 812-855-0193
Email: hitesr@indiana.edu
Faculty Profile: http://www.indiana.edu/~speaweb/fcltydir/hites.html

David O. Carpenter, M.D.
University at Albany
School of Public Health
One University Place, Room B242
Rensselaer, New York 12144-3456
Phone: 518-525-2660
Email: carpent@uamail.albany.edu
Web: http://www.albany.edu/ihe/index.html

M. Coreen Hamilton
AXYS Analytical Services
Post Office Box 2219
2045 Mills Road
Sidney, British Columbia, Canada V8L 3S8
Web: http://www.axys.com/home.htm

Barbara A. Knuth
Department of Natural Resources
Cornell University
Ithaca, New York 14853
Phone: 607-255-2822
Email: bak3@cornell.edu
Faculty Profile: http://www.dnr.cornell.edu/people/faculty/profiles/knuth.html

Steven J. Schwager
Department of Biological Statistics and Computational Biology
Cornell University
Ithaca, New York 14853
Phone: 607-255-1644
Email: sjs5@cornell.edu

Arctic Science Journeys is a radio service highlighting science, culture, and the environment of the circumpolar north. Produced by the Alaska Sea Grant College Program and the University of Alaska Fairbanks. The shortcut to our ASJ news home page is www.asjnews.org.

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