Survival of Juvenile Lake Trout Stocked in Western Lake Huron during 1974–1992

Abstract

The population of lake trout Salvelinus namaycush in the main basin of Lake Huron collapsed in the late 1940s from the combined effects of overfishing and predation by sea lampreys Petromyzon marinus. Stocking juvenile lake trout has been one of the key management strategies in efforts toward lake trout rehabilitation. However, the survival of juvenile stocked lake trout has decreased over time in lakes Erie, Ontario, and Superior. We examined catch per effort (CPE) for age-5 fish divided by the number of that year-class that was previously stocked to determine whether the survival of juvenile stocked lake trout changed in Michigan waters of Lake Huron. During 1974–1992, this standardized CPE decreased significantly in the northwestern part of Lake Huron but did not change significantly in the central or southwestern parts of the lake. The trend in the northwestern part of the lake probably reflects decreasing juvenile survival attributable to increases in sea lamprey abundance. Our study suggests that stocking hatchery-reared lake trout is still a viable management option for building and maintaining an adult lake trout stock in Lake Huron.