Genetic and Environmental Sources of Variation in Length and Weight of Rainbow Trout (Salmo gairdneri)

Abstract

Rainbow trout (Salmo gairdneri) of three-year-classes (1967–1969) were produced from random mating, and one-year-class (1970) from inbreeding. The two first-year-classes were fullsib groups. Intraclass-correlations for body length in the 1967-year-class were: 0.16, 0.15, 0.09, and 0.17 at 90, 130, 355, and 485 days of age, respectively. The corresponding estimate for the 68-year-class was 0.25 at age 110 days. Phenotypic correlations between body length at different ages were high within seasons, but low between seasons.For the 1969-year-class the sire x dam interaction component was negative at ages 150 and 280 days, indicating that nonadditive gene effects were unimportant. Estimated heritabilities ranged from 0.0 to 0.40, those from the sire component being generally higher. Environmental differences between tanks were low, but not ignorable. The 1970-year-class, produced from first generation of fullsib mating, showed significant differences between inbred and control (noninbred) for mortality of eggs and fry, but not for body weight at age 75 days.