Selective breeding programs that improve salmon disease resistance offer one of the most promising welfare improvements in aquaculture by reducing both disease burden and treatment frequency.
Genetic disease resistance represents a uniquely sustainable approach to salmon welfare improvement because it reduces both the disease burden experienced by fish and the treatment interventions required to manage it. This is welfare improvement through prevention rather than treatment - a fundamentally more welfare-positive approach than relying on medical interventions that themselves cause stress. The Norwegian salmon industry's dramatic reduction in antibiotic use, achieved partly through vaccination and disease-resistant genetics, demonstrates what is achievable. Welfare science evaluation of breeding programs should include broad welfare trait assessment to ensure that selection for disease resistance does not inadvertently compromise other welfare-relevant characteristics.