Association between initial weight and weight gain in brook trout, Salvelinus fontinalis Mitchill, and brown trout, Salmo trutta L.

Abstract. Individual weighings of samples of brook trout, Salvelinus fontinalis Mitchill, and brown trout, Salmo trutta L., al the initiation and termination of their growth period, enabled estimating the association of weight gain on initial weight. In both cases the regressions were positive and the correlations significant. Variation in initial weight among tested individuals and groups is expected to bias growth estimates of these groups in programmes of genetic testing, as a result of this association. Obviating this bias requires an adequate correcting technique, involving the estimation of an environmentally generated correction factor. Phenotypic regression coefficients, as estimated in this investigation, cannot serve as correction factors, but may be regarded as maximum estimates.