| Summary: | Genetic improvement of Atlantic salmon in Tasmania by Anna Do Within the Tasmanian salmon industry, there remains potential for more efficient production of high quality Atlantic salmon. Fat can be stored throughout the body and, when stored excessively in the viscera, in the muscle, under the skin or in other fat depots, can contribute to production waste. The thesis aims to: (i) determine whether the deposition of fat in various depots are under genetic control and explore if these fat depots are genetically correlated with muscle fat and other production traits; (ii) investigate the use of non-invasive and less destructive methods for measuring muscle fat and compare their cost-effectiveness against a reference method; and (iii) explore the possibility of testing animals early (24 vs 30 months) to shorten the average generation interval. Fat was measured using a number of methods involving visible/near-infrared spectroscopy (VNIRS), a Distell Fish Fatmeter, image analysis and subjective scoring of visceral fat. Genetic parameters were estimated using residual maximum likelihood methods using animal models. Fat stored in various body depots were all heritable (h2 = 0.11 – 0.57) but had limited genetic correlations with each other. Less destructive and non-invasive measures of fat were moderately heritable (h2 = 0.36 – 0.56), with genetic correlations with the reference method ranging from 0.67 to 0.88 and the Distell meter found to be relatively cost-effective. Genetic correlations between biometric and flesh quality measures on fish of 24 and 30 months of age were moderately strong to perfect (rg = 0.65 – 1.00). The thesis shows that, by employing various strategies, Tasmanian Atlantic salmon can be produced more efficiently by lowering production waste, allowing recovery of product after performance testing and increasing the rate of genetic gain in economically-important traits.
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