Selective breeding has produced salmon that grow rapidly but may be prone to health problems. Incorporating welfare traits into salmon breeding programmes could reduce suffering for billions of fish.
The genetics of farmed salmon profoundly shape their welfare outcomes. Decades of selection for rapid growth has created fish that grow fast but may be less robust - more prone to skeletal deformities, cardiovascular problems and immune vulnerabilities. The recognition of this problem has led to a shift in breeding objectives at major genetic suppliers like SalmoBreed and Benchmark, who now include disease resistance, skeletal health and stress tolerance in selection programmes. This is encouraging, but commercial pressures continue to favour growth. Regulatory requirements for welfare trait inclusion in breeding objectives would accelerate the transition to more robust, welfare-appropriate genetics.