Last month Norwegian research institute Nofima published an article about trials that showed that salmon from the same families grew differently at high and low temperatures (17°C and 5°C), and that it is possible to breed against temperature sensitivity so that the salmon get good growth at different temperatures.
However, AquaGen said its own data show that good growth is a property that salmon can have in all environments and under different temperature regimes.
“Growth in farmed fish is a trait that is affected by many genes and other factors, such as temperature, feed and feeding and health status,” wrote Trina Galloway, head of social contact and corporate social responsibility at AquaGen.
“Increased growth reduces the production time for salmon and will have a positive effect on fish welfare because it reduces the time the fish spends in the sea phase and the associated risk of disease. Reduced production time will also be able to provide better utilisation of fish farms and licences, and thus have a positive effect on environmental and economic sustainability related to salmon production.
“Since the start of the salmon breeding programme almost 50 years ago, AquaGen has had growth as one of the most important breeding goals. We have also investigated whether it is possible to breed for increased temperature tolerance, i.e., salmon that are adapted to different temperatures, to help the salmon farming industry to be better prepared for increased sea temperatures as a result of future climate change. The experiments were carried out within a temperature range between 4 and 20 degrees, and thus cover the salmon’s optimal growth temperature (around 14 degrees).
A universal trait
“We find a high heritability for growth trait (h2 ~ 0.5), and a high genetic correlation (~ 0.75-0.85) between salmon growth in very different environments; for example, high temperature compared to low temperature, Northern Norway compared to Southern Norway, Norway compared to Chile, or land-based compared to sea-based.
“Growth thus seems to be a universal trait, i.e., one and the same family with good growth traits will perform well, regardless of the environment in which they are produced. Thus, the best breeding candidates can be selected effectively for all types of production based on measuring growth in a standard production. However, one should be aware that any diseases in the sea phase, such as PD, affect appetite and growth.
“Our data thus show that with a good selection for growth, you will get good performance in all relevant production environments.”