Contribution of Hatchery-Reared Fish to Chinook Salmon Populations and Sport Fisheries in Lake Superior

Abstract

Abstract Chinook salmon Oncorhynchus tshawytscha stocked in Lake Superior since 1967 to diversify the sport fishery were suspected of reproducing. An abundance of naturalized chinook salmon would reduce the need for hatchery fish but also would decrease our ability to manage chinook populations and their effect on the Lake Superior fish community. Our study objective was to determine the relative contribution of hatchery and wild fish to chinook salmon populations in Lake Superior. All chinook salmon stocked in Lake Superior in 1988, 1989, and 1990 were marked with an agency-specific fin clip. Contribution of these marked year-classes were determined from their representation in sampled sport fisheries and spawning runs. Hatchery fish made up 9, 25, 32, and 57% of chinook salmon sampled in Ontario, Michigan, Wisconsin, and Minnesota waters of Lake Superior during 1990–1994. Hatchery chinook salmon stocked by each state or provincial agency were caught in each of the other Lake Superior jurisdictions, and ...