The role of hatcheries in the decline of Lake Ontario Atlantic salmon

Abstract

Lake Ontario Atlantic salmon (Salmo salar) were one of the first species of fish to be cultured in Canada. Their story goes from abundance in the 1700s to protective legislation in 1807, then hatchery culture in 1866 and finally ends in extirpation in 1898. The standard narrative is that Samuel Wilmot’s hatchery efforts briefly staved off their loss from the Lake Ontario basin. However, that story is replete with inaccurate assumptions, unfounded faith in technological solutions, and a belief that numbers of fish released was an accurate measure of success. We challenge the narrative around the perceived benefits of these hatchery efforts and suggest instead that they contributed to the decline of Atlantic salmon in Lake Ontario through the mining of wild gametes, transferring eggs out of basin, mixing locally adapted populations across streams, and the negative genetic effects of releasing hatchery fish.