Inter-population differences in farmed Chinook salmon product quantity and quality

In British Columbia, Atlantic salmon ( Salmo salar ) are the top finfish aquaculture export of the province, although native Chinook salmon ( Oncorhynchus tshawytscha ) are also farmed locally. Few commercial facilities rear Chinook salmon, limiting the availability and development of their broodstocks, potentially reducing the ability to improve product quantity and quality. Due to the potential for inbreeding in these stocks, a need to determine whether product quantity and quality can be improved through outbreeding with wild populations exists. In this study, we examined the effects of outbreeding on farmed salmon by comparing product quantity and quality metrics in six experimental populations of outbred (wild × farmed) Chinook salmon and one farmed (control) population. Specifically, we measured fillet yield, slaughter yield, lipid content and flesh colour score in three-year old market-sized salmon immediately post-slaughter. We found significant differences across populations for slaughter yield, fillet yield and flesh colour score but found no differences across populations in lipid content. For flesh colour score, slaughter and fillet yield, the control farmed population performed similarly to the highest performing outbred populations. These results suggest that outbreeding inbred farmed populations with wild populations can maintain high product quality while adding new genes to a population.