Survival, Growth, Spawning Distribution, and Movements of Introduced and Native Lake Trout (Salvelinus namaycush) in Two Inland Ontario Lakes

Abstract

This paper attempts to develop a biological basis for the management of stocks of lake trout (Salvelinus namaycush). Recent studies of the influence of genetic differences on the survival of planted stocks of trout and of the spatial distribution and movements of lake trout populations are reported. The genetic origin of planted lake trout influenced their survival in four Ontario lakes, whereas water hardness of the rearing hatchery had little effect. Survival also appeared to be influenced by the status of the native population but growth rates of native and introduced trout were similar. Age of first maturity appeared to differ between stocks in Lake Simcoe. Studies with both numbered and sonic tags in Lake Opeongo suggested that lake trout do not home to their natal shoal. Differences in total distances travelled were observed between sexes, but both males and females moved between shoals at spawning time. In Lake Simcoe, planted trout dispersed widely, colonizing spawning shoals up to 30 km from release sites, and no differences between stocks in time of spawning could be detected despite apparent differences in the home lakes. Temperature influenced spawning time and accounted for most of the timing variation between two allopatric lake trout stocks.Key words: lake trout, native, introduced, survival, growth rate, spawning distribution, movement, homing