The power of genetics: Past and future contribution of balanced genetic selection to sustainable growth and productivity of the Norwegian Atlantic salmon (Salmo salar) industry

In less than 50 years Atlantic salmon farming has become a major industry in Norway, and several attempts at predicting future growth have been made. In all food production, genetics has played an important role in production optimisation and efficiency. The benefits of genetic selection in aquaculture are less documented due to a variable production environment, long production time and challenges such as sea-lice, infectious diseases, and market fluctuations. This study investigates the impact of 50 years of balanced genetic selection on growth and productivity of the Norwegian Atlantic salmon industry. In a common garden experiment eggs from females representing present-day farmed Atlantic salmon (generation 11), were fertilised with cryo-preserved milt from males representing previous generations, and the progeny (half-sib families) were reared under the same commercial farming conditions. At the termination of this experiment, the difference in average body weight between generation 0 and half-sibs from present-day salmon was 1.5 kg. The results from the common garden experiment were used to model the contribution of genetic selection for increased salmon growth rate to the industry from generation 0 (harvested in 1975-1978) to generation 11 (harvested in 2017 - 2019) and to simulate the power of genetics for expected industry growth until 2050 (generation 24) giving four different forecast scenarios. We found that a total Norwegian production of 2.5 to 3.2 million tonnes could be achieved in 2050 solely by improving the inherent growth potential of Atlantic salmon through genetic selection. Further, the production time in seawater is expected to be reduced by 40 to 53% from 15.3 months in 2019 to a production time ranging from 9.2 to 7.2 months in 2050, respectively. Reduced production time in seawater results in reduced time at risk of diseases and other unfortunate events, and in our most progressive scenario, mortality in seawater was expected to be reduced by up to 50%. The contribution to reduced losses and increased resource utilisation, increases the sustainability of the Norwegian aquaculture industry. This study demonstrated that it is possible to significantly increase the Norwegian aquaculture production by genetic improvement, and that contribution from genetic selection for growth rate alone can close 77% of the gap of the forecasted five million tonnes in 2050. These scenarios demonstrate that genetic selection should be included as a central component when predicting future development and growth of aquaculture production, both in Norway and other salmon producing countries.