Salmon farming''s
impacts on
wild salmonid populations—which have undergone drastic
declines in the North Atlantic and northeastern Pacific since the late 1980s—are even worse than feared. Farming carnivorous fish like
Salmon depletes wild stocks of other species—on average, every pound of
farmed salmon consumes three pounds of wild-caught fish. Escapees may reduce survival rates of wild populations—a major concern for Atlantic salmon, the most popular farmed salmon species—by competing for mates and diluting the genetic makeup of their wild counterparts through hybridization. In their new study, Ford and Myers analyze the impacts of salmon
farms around the globe and report that farms dramatically reduce survival rates of wild salmonids that migrate past aquaculture operations as juveniles on their way to the ocean. Atlantic salmon (and Irish sea trout) populations suffered greater declines than Pacific salmon did, possibly because wild and farmed Atlantic salmon can interbreed, adding any deleterious genetic effects to other potential impacts. British Columbia pink salmon also showed more substantial declines linked to salmon farming. Though some environmental organizations want to eliminate salmon
farming altogether, removing aquaculture operations from the migratory path of wild juveniles—or not placing them along migration corridors to begin with—would greatly improve the survival of wild populations.
More abstracts about the Can Farmed and Wild Salmon Coexist?