Decades of selective breeding have transformed farmed salmon biology. Understanding how genetic selection affects welfare helps evaluate breeding programmes for their welfare implications.
Salmon genetics plays a fundamental role in determining the welfare potential of farmed fish, as the biological characteristics of farm fish determine how well they can cope with aquaculture conditions. Rapid growth genetics that improve production efficiency may simultaneously increase vulnerability to deformity and cardiovascular strain, creating welfare costs. Reduced stress reactivity from domestication may improve fish welfare in routine farm conditions but could reduce adaptive capacity to cope with acute stressors. Breeding programmes that explicitly include welfare traits alongside production traits represent the most progressive approach, but require investment in welfare science to identify which traits are heritable and how to measure them reliably. The long-term welfare of farmed salmon populations depends significantly on how genetic selection programmes are designed and regulated.