In recent years, the global production of farmed fish has exploded. There have been many ecological concerns over aquaculture practices, but when it came to health issues, matters were overlooked until the publication of a controversial paper in Science, 2004. Since then, debates over the safety and health issues of fish consumption have intensified. This article explains that it is not only safe, but beneficial to our health to consume both wild and farmed salmon.
rdott_s, Fishing for art by NecronLich16, 2007
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In the past 15 years, global production of farmed fish, including salmon, has more than doubled(1). In general, growth in aquaculture production relieves pressure on ocean fisheries. However, the opposite is true in certain cases, such as the farming of carnivorous fish (e.g. salmon, cod, tuna, marine shrimp, and eel). The use of wild fish (e.g. anchovies, sardines, capelin, and Alaskan Pollack) to feed farmed fish places direct pressure on fishery resources. Furthermore, there have been other ecological concerns over aquaculture practices like habitat modification, introduction of non-native species, increases in local and foreign diseases and pathogens, and increases in fish sewage (1;2). But what about health and safety issues?
In 2004, Ronald Hites and his colleagues (3) analyzed over two metric tons of farmed and wild salmon from around the world for organochlorine contaminants (e.g. PCBs (polychlorinated biphenyls), dioxins (herbicide), toxaphene (insecticide), and dieldrin (insecticide) and showed that concentrations of these contaminants were significantly higher in farmed salmon than in wild. Hites, therefore, concluded that the consumption of farmed Atlantic salmon may pose a health risk, argued that to offset this risk an average of eight ounces or less should be consumed per month-roughly equivalent to two servings (3). These controversial findings provoked extensive media coverage and attracted intense public interest over the health risks associated with consuming farmed salmon.
By contrast, government agencies such as Health Canada, Food and Drug Administration (FDA) in the United States, European Union (EU), and World Health Organisation (WHO) stated that consuming farmed salmon does not pose any health risks to consumers (4). Average level of PCBs (i.e. polychlorinated biphenyls, carcinogen; e.g. fluids commonly found in industrial capacitors & transformers, such as flame retardants) found in both wild and farmed salmon is 27 parts per billion (ppb), while current Health Canada’s guideline on PCBs is 2000 ppb. Furthermore, in some regions such as the Puget Sound and the Columbia River, wild salmon contain similar or higher amounts of PCBs than do farmed salmon(5). To add even more perspective, the level of PCBs found in roasted chicken breast, roasted beef steak, and pan-cooked pork chop range between 21 and 32 ppb(5). The controversial paper (3) also overlooked the beneficial effects of consuming fish (e.g. salmon) in general. Salmon and other fish are important sources of protein, vitamin B-12, and iron (6). Moreover, both farmed and wild salmon contain high amounts of omega-3-fatty acid (7). Omega-3-fatty acid is known to lower the risk of coronary heart diseases in both men and women (8;9) and is beneficial to brain development (10).
True, it is alarming that the fish we eat contain contaminants. Strict monitoring and management practices in both the food and aquaculture industries should be implemented to further reduce the level of pollutants found in both wild and farmed salmon. Nevertheless, the present level of organochlorine contaminants found in salmon does not pose a significant health risk. Furthermore, consumption of both wild and farmed salmon is safe and beneficial to one’s overall health. Unfortunately, other concerns such as the effects of antibiotics, vitamins, hormones, and pigments are becoming issues for the aquaculture industries (2) and hence deserve the public attention.
References
(1) Naylor, Rosamond L. et al. “Effect of aquaculture on world fish supplies”. Nature 405 (2000): 1017-1024.
(2) FAO Fisheries Department. FAO Fisheries Technical Paper No. 500: State of world aquaculture 2006. Rome: FAO, 2006.
(3) Hites, Ronald A. et al. “Global assessment of organic contaminants in farmed salmon”. Science 303 (2004): 226-229.
(4) Health Canada. “Q’s & A’s on PCBs in salmon and food safety”. Jan. 2004. Health Canada 24 Mar. 2007<http://www.hc-sc.gc.ca/ahc-asc/media/nr-cp/2004/2004_pcb-bpcbk1_e.html>.
(5) Mcclure, Robert and Stiffler, Lisa. “Sound’s salmon carry high PCB levels”. Jan. 2004.Seattle post – intelligencer reporters 24 Mar. 2007 <http://seattlepi.nwsource.com/local/156714_warning15.html>.
(6) Department of Fisheries and Oceans Canada. ”FACT SHEET – BENEFITS AND RISKS OF CONSUMING FISH AND SHELLFISH”. Jun. 2006. Department of Fisheries and Oceans Canada 24 Mar. 2007 <http://www.dfo-mpo.gc.ca/Aquaculture/sheet_feuillet/benefits_risks_e.htm>.
(7) Morin, Richard. “Farmed salmonids are an excellent source of omega-3 fatty acids and contain very few residues of environmental contaminants”. Jun. 2006. Innovation and Technologies Branch, ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ) 24 Mar. 2007<http://www.dfo-mpo.gc.ca/aquaculture/ref/morin_aaq_e.htm>.
(8) Hu, Frank B. et al. “Fish and Omega-3-fatty acid intake and risk of coronary heart disease in women”. Journal of American Medical Association 287 (2002): 1815-1821.
(9) Mozaffarian, Dariush and Rimm, Eric B. “Fish intake, contaminants, and human health evaluating the risks and the benefits”. Journal of American Medical Association 296 (2006): 1885-1899.
(10) Simopoulos, AP. “Omega-3-fatty-acids in health and disease”. American Journal of Clinical Nutrition 54 (1991): 438-463.