Salmon farming has a number of negative impacts that affect the area immediately surrounding the farm and very distant ecosystems.
Carnivorous Farm Salmon
Farm salmon are obviously carnivorous fish and as a result need to be fed feed pellets that contain fishmeal and fish oils that are derived from wild fish captured in the southern hemisphere—regulations in Canada prevent capturing fish for the sole purpose of producing feed. Although efforts are always being made to reduce the amount of fishmeal and fish oils used to produce feed, largely for economic reasons, there are still considerable feed fisheries for species like anchovies and sardines taking place that have significant effects on local ecosystems and economies. Hence, raising carnivorous species such as salmon may not be the most efficient way to produce fish since wild fish that could otherwise be eaten are instead processed into feed for salmon.
Marine Mammal Deaths
Other impacts occur closer to home. Marine mammals such as seals, sea lions and dolphins may view salmon farms as a source of an easy meal, however, they can get tangled in the nets or be killed by salmon farmers. It has been reported that over 5,947 harbour seals and 1,057 sea lions were shot trying to access farms in BC between 1989 and 2008. Larger marine mammals are not immune to farm nets. In 2008, a humpback whale became entangled in a farm. The Calling from the Coast video by Twyla Roscovich clearly shows what happens to some unfortunate marine mammals that get too close to salmon farms.