Restoration Management of Lake Trout in Lake Ontario – 41 Years and Still Not There

Historically, Lake Trout were the most abundant large predator native to Lake Ontario’s deep offshore waters.  Overfishing had already depleted stocks by the late-1800s and that pressure coupled with Sea Lamprey predation drove the population to extirpation in the 1950s.  An early (1953-1964) attempt to restore Lake Trout failed due to harvest by the commercial Whitefish fishery and predation by Sea Lampreys.  Contemporary restoration began in the early 1970s with the start of Sea Lamprey control and restoration stocking.  While the population reached high abundance in the mid-1980s and natural reproduction was detected by the 1990s, the contribution of natural recruits is low and stocking remains necessary.  Considerable successes have been attained by management for most population restoration targets (e.g., Sea lamprey control, stocking numbers, adult survivorship; and population fecundity) other than reproduction.  Impediments preventing restoration include the effects of a diet dominated by thiaminase rich alewife, erosion of spawning habitat quality, and the absence of a large bodied preyfish community in the deep off shore waters.  Future prospects for Lake Trout restoration remain uncertain especially in light of management and the public’s acceptance of fish community objectives that emphasize co-management of Alewife and Chinook salmon to support the lucrative sport fishery.