Salmon Farming Impacts

Fish Feed

Salmon farmers often claim their industry is helping to “feed the world.” In truth, the salmon farming industry contributes to the pressures on already overstressed global wild fish stocks, can strain the food supply for people in poorer nations, and removes massive quantities of small fish from the ocean food chain.

Depending on the production region, 1.5 – 8 kilograms of wild fish are needed to produce one kilogram of farmed salmon.

  • “With global [fish] catches declining since the late 1980s, continuation of present trends will lead to supply shortfall, for which aquaculture cannot be expected to compensate, and may well exacerbate.” Daniel Pauly et al. (2005) Nature

Salmon feed is made, in part, from fishmeal and fish oil—concentrated products requiring much larger volumes of small ocean fish (such as anchovies, herring and sardines) to produce one serving of food for a person than would be required if these were consumed directly.

Much of the wild feed for BC farmed salmon is taken from the southern hemisphere, diverting local protein to raise a luxury product for northern consumers. Amongst countries Canada imports seafood from, Peru — a significant source of cheap fish for feed production — ranks third by volume.

The economic incentive to speed the growth of farmed species has led to the use of an increasingly high-energy diet, which means farmed salmon have a higher fat content than their wild counterparts. This makes them more vulnerable to contamination by fat-soluble pollutants (i.e. PCBs) that accumulate up the food chain.

And, since feed ingredients are sourced from fisheries all over the world, “local” farmed salmon can contain contaminants from distant seas. There are regional variations in contaminant levels depending on where the feed was sourced and where the fish are raised.

Over two-thirds of the total global salmon aquafeed production is produced by two companies: Skretting (Nutreco) and Ewos (Cermaq).

Attempts to shift salmon feed away from marine sources due to rising costs and reduced availability introduces entirely new issues and concerns:

  • Byproduct feed – in Canada, farmed salmon can be fed byproducts from poultry processing such as feathers, necks and intestines;
  • Genetically Modified Organisms (GMOs) – farmed salmon can be fed genetically modified soy and canola;
  • The environmental impacts of growing genetically modified organisms has not been adequately assessed.