Assessment of Winter Planting of Hatchery-Reared Brook Trout (Salvelinus fontinalis) in Small Precambrian Lakes

Abstract

Distinctively marked 8-mo-old brook trout (Salvelinus fontinalis) were planted in autumn, 14-mo-old in winter, and 16-mo-old in spring in 10 experiments conducted on five small Ontario lakes in 1970–73. Comparative recoveries were assessed by examining the anglers’ catch and by intensive sampling with gillnets 1 mo following the spring planting. Recovery of spring-planted trout (mean 39.7%) was significantly higher (P < 0.01) than for winter- (15.7%) and autumn-planted trout (7.7%). Although there was evidence in one lake of predation on winter-planted trout by large brook trout and splake (S. fontinalis × S. namaycush), the factors generally responsible for the large losses of winter- and fall-planted trout have not been identified.