Studies on carcass quality traits in two populations of Coho salmon ( Oncorhynchus kisutch): phenotypic and genetic parameters

Abstract

Phenotypic and genetic parameter estimates of carcass quality traits were obtained from two pedigreed populations, termed even and odd, of a Coho salmon breeding program. Carcass quality data from 3444 fish (1802 male and 1642 female), harvested at 21 months of age, were analyzed. In both populations, significant sex effects were found for body weight (3487–3354 g, male and female, respectively), total visceral weight (448–397 g), gonad weight (239–166 g), abdominal fat percentage (8.9–10%), fillet percentage (56.5–59.3%), total width of steak (8.2–8.0 cm), area of cutlet (231–217 cm 3), but not for abdominal fat weight (40.8–40.8 g), total fillet weight (2284–2263 g), texture of flesh (1.47–1.46 Kg) and fat content of flesh (18.0–18.1%). Less consistent significant sex effects were found for carcass weight (3086–2944 g, odd population), dressing percentage (86.9–88.8, even population), dorsal fat thickness (1.77–1.71 cm, odd), ventral thickness (1.14–1.17 cm, even) and height of cutlet (5.0–4.7 cm, odd). Heritability estimated for carcass quality traits was medium in magnitude for total visceral weight (0.19–0.33, even and odd), gonad weight (0.26–0.33), abdominal fat weight (0.24–0.35), abdominal fat percentage (0.18–0.26), dressing percentage (0.33–0.23), while estimated heritability was low to medium for body weight (0.13–0.24), carcass weight (0.12–0.22), total fillet weight (0.18, odd), fillet percentage (0.11, odd), dorsal fat thickness (0.09–0.15), ventral thickness (0.05–0.22), total width of steak (0.10–0.30), height of cutlet (0.09–0.24), area of cutlet (0.11–0.33), texture of flesh (0.06–0.09) and fat content of flesh (0.17, even). Estimated genetic correlations ( r g) between various biometrical traits of fish were all positive and ranged from 0.48 to 0.96, while the phenotypic correlations ranged from 0.33 to 0.90. Selection for increased body weight (growth) will produce favourable changes in carcass weight ( r g=0.99), fillet percentage (0.98), and texture (0.30–0.70), but unfavourable changes in dressing percentage (−0.48 to −0.03) and fat content of flesh (0.73). Estimates of genetic correlation were positive and moderate between abdominal fat percentage and fat content of flesh (0.46), and were negative between abdominal fat percentage and carcass weight (−0.45), and between abdominal fat percentage and dressing percentage (−0.44 to −0.11).