Genetic selection for disease resistance in Atlantic salmon represents one of the most promising pathways to improving welfare at scale in aquaculture.
Disease resistance genetics is a welfare intervention that operates at the population level: selecting fish that are less susceptible to disease reduces the burden of illness, death, and treatment stress experienced by billions of individual fish annually. The welfare benefits are direct and substantial. The challenge is ensuring that disease resistance is not selected in isolation from other welfare-relevant traits — particularly as increased growth and altered immune function can have unintended consequences. Integrated welfare breeding objectives that include disease resistance, robustness, stress resilience, and absence of deformities represent the most welfare-positive approach to salmon genetics.