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Genetic and phenotypic evaluation of harvest traits from a comprehensive commercial Atlantic salmon, Salmo salar L., broodstock program

Garber, A.F., Amini, F., Gezan, S.A., Swift, B.D., Hodkinson, S.E., Nickerson, J., Bridger, C.J.
Aquaculture 2019 v.503 pp. 242-253
Salmo salar, breeding stock, color, discoloration, environmental factors, fillet quality, filleting, fillets, fish production, heritability, marbling, melanin, phenotype, phenotypic correlation, salmon, selection index
Twenty-two harvest carcass quantity and fillet quality traits, including nine calculated traits, were evaluated on 1496 North American origin farmed Atlantic salmon (mean weight ~5.5 kg) belonging to 81 families. Narrow-sense heritabilities along with a description of the variability of the traits, effects of sex and maturity status, and genetic and phenotypic correlations between the traits are presented and discussed. In addition, these traits are comprehensively compared to published results, when available, on Atlantic salmon and other fish species. All recorded carcass quantity traits were heritable (h2 = 0.30–0.48), indicating additive genetic control that can be exploited towards improvement, and their genetic and phenotypic correlations with one another are discussed. Quality traits related to melanin discoloration, gaping and marbling were less heritable (h2 = 0.04–0.15), but were at a reduced level overall in the group of salmon sampled. These secondary traits are considered useful as tracking traits to ensure their frequency does not increase over time due to genetic practices or to environmental factors that affect fish production. Fillet color was discussed from both visual and instrumental evaluation (h2 ≥ 0.42), including the negative and/or positive genetic and phenotypic correlations of varying degrees, making this trait difficult to incorporate into a selection index. Fillet color (all phenotypic measures) also lacked genetic and phenotypic correlations to fillet weight and other weight associated traits indicating that improvement in growth does not result in any changes in color. Calculated traits are presented related to yield, as these are often the most commonly discussed with commercial fish producers, resulting in moderate heritabilities (h2 = 0.14–0.27). Finally, implications of these harvest evaluation results to manage a commercial Atlantic salmon broodstock program are also discussed in detail.