Recovery of Planted Brook Trout, Splake, and Rainbow Trout from Selected Ontario Lakes

Abstract

Recoveries of hatchery-reared brook trout (Salvelinus fontinalis), splake (Salvelinus namaycush × S. fontinalis), and rainbow trout (Salmo gairdneri), planted in lakes having different resident fishes, were highest (9–30%) in a lake in which minnows and the brook stickleback were the only other fishes. Recoveries, by angling and gillnetting, were considerably lower (2–15%) in two lakes containing the white sucker and minnows, and still lower (0.5–5%,) in two lakes containing spiny-rayed species as well. Recoveries were lowest (< 0.5%) in a lake having a complex fish community that included native brook and lake trout. Planted splake and rainbow trout generally yielded higher returns, in weight, than brook trout in comparable situations.The low survival of planted fish was apparently due to the low fertility of the waters and to competition with, or predation by, resident fish species. Predation by fish-eating birds and mammals may also have had an effect.The weight of the catch of salmonids exceeded the weight planted in only one lake. Here, the mean yield of planted salmonids was 8.4 kg/ha per year in comparison with 2.6 to < 0.5 kg/ha per year in the five other study lakes.