COMPARATIVE ECOLOGY AND BEHAVIOR OF DOMESTIC, HYBRID, AND WILD STRAINS OF BROOK TROUT, SALVELINUS-FONTINALIS, AFTER STOCKING

Two years after planting in 6 small oligotrophic lakes, domestic, hybrid and wild strains of brook trout, used space and food resources in the same way as native trout. Although trout, living with or without white sucker Catostomus commersoni were similarly spatially distributed, they had different diets, suggesting a feeding niche shift of trout in the presence of sucker; this shift is under phenotypic control because each planted strain came from similar genetic backgrounds. Sexual maturity was related to the size of individuals, regardless of the strain, and males matured before females. Almost all males and females were sexually mature in the 1st fall after stocking except wild females (3.0 and 75% matured during the 1st and 2nd fall, respectively). Fecundity of domestic females, after correction for size differences, was significantly higher than that of hybrid females which, in turn, was significantly higher than that of wild ones. -from Authors