Phenotypic and genetic parameters of body composition traits and flesh colour in Atlantic salmon, Salmo salar L.

Data obtained on 3.5-year-old offspring of 58 sires and 171 dams (two year classes) of Atlantic salmon, Salmo salar L., were analysed. A substantial effect of sexual maturation status was demonstrated for several body composition traits, most pronounced for the content of fat and dry matter of muscle. Maturation effects generally exceeded estimated sex effects. Intermediate estimates of heritability (0.20-0.30) derived from the sire component of variance were obtained for intestinal fat weight, intestinal fat index, dressing percentage and fat and dry matter content of muscle. Corresponding parameters of the subjectively scored traits belly flap constitution, amount of intestinal fat and flesh colour were all low (= 0.10). Heritabilities derived from the sire and dam components of variance were generally similar in magnitude, indicating the absence of non-additive genetic and environmental effects common to full-sibs. Viewed in the context of likely selection goals for commercial breeding schemes, the results did not reveal major adverse genetic relationships among the investigated traits. However, the estimated genetic correlations of muscle fat with body weight (0.42 ± 0.17) and intestinal fat index (-0.64 ± 0.19) may be unfavourable.