Salmon feed typically contains synthetic colors, added to make farmers' fish pink—a fact known to few consumers until recent national headlines uncovered the practice. Farmed salmon would be a very unappealing gray, absent this artifical intervention.
The secret came out only when a consumer group sued three large supermarket chains earlier this year, to force them to tell shoppers that farmed salmon is fed synthetic colors. The Seattle Post-Intelligencer quoted the plaintiff's attorney, who said, "It's unfair, it's deceptive and it's against the law." The paper went on to quote a salmon farmers' spokesman, who countered, "These are the same molecules that make wild salmon pink."
Sadly, salmon farmers are not being honest about this issue. Most use commercial feeds containing a synthetic version of the natural pigment astaxanthin, derived from petrochemicals. In contrast, wild salmon develop their pink/red flesh naturally by feeding on prey such as krill (tiny shrimp-like crustaceans), which in turn feed on algae rich in the reddish pigment astaxanthin. Krill and other salmon prey also contain other antioxidants and nutrients good for the health of salmon and humans.
The artificial astaxanthin added to salmon feed differs from the naturally occurring astaxanthin in the diets and flesh of wild salmon in its "optical isomeric distribution." While this obscure distinction may sound innocuous, studies show that fish that consume synthetic astaxanthin in their commercial fishmeal grow more slowly than fish that consume the same amount of astaxanthin from natural feed containing the same amount of calories per gram. This is an indication that it does not function identically in salmon's bodies—and maybe not in people's bodies, either.
And there is concern about the safety of canthaxanthin, another carotenoid pigment additive used in salmon feed. As Marion Burros wrote this spring in the New York Times (May 28, 2003), "European Union officials are reducing the permissible levels of canthaxanthin in fish and poultry from 80 parts per million per kilogram of feed—the levels permitted in this country—to 25 parts per million because there is some concern that high levels may cause retinal damage. In Canada the permissible level is 30 parts per million."
Wider implications of artificial color
The controversy over artificial salmon color shines a light on three significant issues: the nutritional quality, safety, and flavor of farmed versus wild salmon. Data compiled by the USDA show that wild salmon are nutritionally superior to farmed salmon in at least two ways:
- Wild salmon are lower in unhealthful saturated fats, having only about half as much as the typical farmed salmon.
- Wild salmon have a healthier ratio of omega 6 to omega 3 fats. Americans consume far too many omega-6s and not enough omega-3s. Most experts call for a ratio of 3:1, which is the ratio found in wild salmon. Due to the grains in their diet, farmed salmon may have up to a 10:1 ratio or worse.
Two recent studies indicate that farmed salmon are less safe than wild salmon. Both research teams found that farmed salmon had significantly higher levels of toxic dioxins, furans, and PCBs, with PCB levels about ten times higher in the farmed fish. The authors concluded that regular consumption of farmed salmon could lead to toxin intakes above the tolerable weekly intake for these chemicals—especially for PCBs and especially for children under five.
The researchers blamed salmon feed. Farmed salmon are fed a diet far richer in fish oils than their wild counterparts consume. This fatty diet allows them to reach market size sooner—but it contains a hidden danger: the herring oil typically fed to salmon is high in fat-soluble toxins like dioxins and PCBs.
Commercial fish feed also yields salmon with inferior flavor and texture. According to Mark Bittman, the noted seafood cookbook author, "If I had a choice of fresh farm-raised salmon and sockeye frozen from last year's harvest, I'd take the sockeye." At a panel discussion on at the West Coast Seafood Show in Los Angeles, Executive Chef Daniel Long of Bon Appetit said, 'To be perfectly honest, it [farmed salmon] is crap. Wild salmon is much better." And in a recent Wall Street Journal taste test, the panel scored farmed salmon only 4.83 out of 10 for overall quality, while wild salmon rated a 9.7.
Once you look beneath growers' propaganda, it seems that farmed salmon can't hide their true, unappetizing colors.
- U.S. Department of Agriculture, Agricultural Research Service. 2002. USDA National Nutrient Database for Standard Reference, Release 15. Nutrient Data Laboratory Home Page, http://www.nal.usda.gov/fnic/foodcomp.
- Fatty acid content of farmed and wild fish. Soon-Mi Shim and Charles R. Santerre, Ph.D. (2003); Department of Foods and Nutrition; Purdue University; 700 W. State St., West Lafayette, IN 47907-2059. (revised 1/21/2003) [http://fn.cfs.purdue.edu/anglingindiana/AquaculturevsWildFish/FattyAcidsFarm.pdf]
- Easton MD, Luszniak D, Von der GE. Preliminary examination of contaminant loadings in farmed salmon, wild salmon and commercial salmon feed. Chemosphere. 2002 Feb;46(7):1053-74.
- Jacobs M, Ferrario J, Byrne C. Investigation of polychlorinated dibenzo-p-dioxins, dibenzo-p-furans and selected coplanar biphenyls in Scottish farmed Atlantic salmon (Salmo salar). Chemosphere. 2002 Apr;47(2):183-91.
- AquaxanÔ HD algal meal use in aquaculture diets: Enhancing nutritional performance and pigmentation. Technical report 2102.001. [http://www.fda.gov/ohrms/dockets/dailys/00/jun00/061900/rpt0065_tab6.pdf]
- Reifenberg, A. (2000). "Taste Test: Wild vs Farmed Salmon." The Wall Street Journal, 5 January, NW3. [http://www.sectionz.info/issue_1/Facts_Footnotes.html]