The farmed fish that claim a growing share of supermarket seafood shelves may not be as healthful as consumers think. The aquaculture business, which one critic says has "a modern gold rush mentality," faces questions raised in several recent studies.
A pilot study published in the February 2002 issue of the journal Chemosphere found that a small sample of farm-raised salmon had much higher levels of contaminants such as PCBs, polybrominated diphenylethers (PBDEs), and organochlorine pesticides than a small sample of wild salmon. The authors also tested five commercial salmon feed sources, and found high levels of the same contaminants, as well as polycyclic aromatic hydrocarbons (which also were present in the farm-raised and wild salmon), in all samples. They conclude, in line with previous studies, that the farm-raised salmon likely are being contaminated through their feed. They are raising money for a larger study.
The authors also compare their findings to fish contamination standards of the World Health Organization, Canada, and the U.S., and note the substantial differences in the standards. Using the most restrictive standards, those of the WHO, they suggest that people limit their consumption of farm-raised salmon to 1-3 meals a week.
The lead author, Michael Easton, is president of a company that assesses effects of contaminants on genes of vertebrates: 604-986-2400. Article abstract (contact author for full article, and for unpublished letter to journal by a critic, as well as Easton's unpublished response).
On March 21, 2002, the Institute for Agriculture and Trade Policy released a report on antibiotics used in aquaculture. The report emphasizes how little data is available about aquaculture in general, and antibiotic use in particular. However, using a series of estimates, Charles Benbrook (report author and source of the "gold rush" comment) calculates that anywhere from 204,000 to 433,000 pounds of antibiotics are used in U.S. aquaculture operations each year. Much more is used overseas, which is the source of about two-thirds of U.S. seafood. Benbrook, 208-263-5236.
The National Aquaculture Association says its estimated 4,000 operators use only about 70,000 pounds of antibiotics each year, but also has little hard data to support its estimate. NAA says some of its members (who raise about 35 species of food fish in fresh and salt waters, as well as many ornamental species) are using alternative management practices, such as withholding food for several days, to better control disease outbreaks. NAA: Randy MacMillan, 304-728-2167.
See TipSheet of March 6, 2002, for information on the recently released USGS study of water contaminants, many of which are antibiotics. Four other recent TipSheets also address antibiotics -- Nov. 14, 2001, June 20, 2001, Dec. 20, 2000, and April 5, 2000.
Numerous agencies play a role in aquaculture (FDA, EPA, USDA, FWS, NMFS, and state agencies). Oversight of many facets of the industry often is minimal, and tends to respond to reports of problems, critics say. The FDA found a number of contaminants in salmon, tuna, haddock, and shrimp in its September 2000 Total Diet Study (scheduled to be updated in October or November 2002). FDA Center for Food Safety and Applied Nutrition: Sebastian Cianci, 301-436-2291. FDA Center for Veterinary Medicine: Linda Grassie, 301-827-3796.
Both wild and farm-raised fish are included in the USDA organic standards that will take effect October 21, 2002, but contamination of food used in aquaculture is not addressed. USDA, Jessica Faust, 202-720-8998. Organic Consumers Association: Ronnie Cummins, 218-226-4164.
The National Academy of Sciences is scheduled to release a report on "The Status and Future of Atlantic Salmon in Maine" (including a review of pertinent aquaculture) by Nov. 30, 2002. NAS: Bill Kearney, 202-334-2138.
See the November/December 2001 issue of Mother Jones and TipSheet of Sept. 12, 2001, for additional aquaculture information.