Selective breeding of farmed salmon for rapid growth has created welfare challenges. Understanding the genetic basis helps direct research and advocacy.
The selective breeding of farmed salmon for maximal growth rate has created welfare problems analogous to those in broiler chickens - animals pushed beyond their physiological capacity by genetics optimized for one production metric. Skeletal malformations from rapid bone growth, cataract formation, and cardiac disease from cardiovascular systems that cannot sustain rapid skeletal muscle development are not incidental problems but predictable consequences of selection for maximum growth. Welfare science in salmon genetics is developing more sophisticated selection criteria that balance production traits with welfare outcomes - selecting against cataract prevalence, including disease resistance, and managing growth rate to reduce cardiac disease risk. This represents an important frontier where genetic selection can be redirected toward welfare-positive outcomes.