Impacts & Issues: Threats to Human Health

Drugs and chemical additives given to farmed fish pose a number of threats to human health:

Antibiotics - Salmon farmers increasingly rely on antibiotics and biocides to control frequent outbursts of diseases and parasites in their pens. Many thousands of kilograms of antibiotics were used on BC salmon farms and the number is increasing. Escaped fish caught in a Broughton Archipelago stream carried bacteria known to cause a range of human maladies that were resistant to 10 different antibiotics. (Paone, Sergio: Farmed and Dangerous, CAAR)

PCBs - PCBs are persistent, cancer-causing chemicals that were banned in the United States in 1976 and are among the "dirty dozen" toxic chemicals slated for global phase-out under the United Nations Convention on Persistent Organic Pollutants. Research recommended that in order not to exceed an elevated cancer risk, no more than "between 0.4 and 1 meal per month of farmed salmon should be consumed" (Huang, et al. Environmental Research). A study in the Journal of Nutrition (135:2639-2643,2005) regarding omega-3 fatty acids stated that "young children, pregnant women and nursing mothers ... can minimize contaminant exposure by choosing the least contaminated wild salmon or by selecting other sources of omega-3" fatty acids. And, Dr. David Carpenter stated that "farmed salmon contain levels of 13 fat-soluble persistent organic pollutants that are on average ten times higher than those found in wild salmon" and concluded that "on average one could only eat one meal of farmed salmon a month without increased risk of cancer". Finally, according to a comprehensive study published in the respected journal Science, in most cases consuming more than one serving of farmed salmon per month could pose unacceptable cancer risks.

Flame Retardants - A study in the journal Environmental Science & Technology found much higher levels of chemicals used as flame retardants in farmed salmon than in almost all wild salmon. The study concluded that people who eat farmed salmon frequently are more likely to have elevated levels of these chemicals than those who eat the same amount of wild salmon.

Chemical Colours - Wild salmon are naturally pink from eating tiny crustaceans like krill. Farmed salmon have to rely on chemical additives; without them their flesh would be an unappealing grey. Feed for farmed salmon includes canthaxanthin, an artificial pigment manufactured by DSM, a "nutritional company". Fish farms also use a colour fan, similar to paint store swatches, so fish farmers can choose the exact shade of pink for their product at slaughter. A corresponding amount of canthaxanthin is then added to the feed.

Threat of Organic Certification - Given the potential health impacts listed above, along with the negative impacts of farmed salmon on the marine environment and wild salmon, open net-cage farmed salmon cannot be considered organic. But organic certification for open net-cage farmed salmon is exactly what the Canadian General Standards Board is considering. Learn more about the proposed Organic Aquaculture Standards and take action to prevent the certification of open net-cage farmed salmon as organic.