Genetic selection in farmed salmon affects both productivity and welfare. Selecting for disease resistance, robust growth, and welfare-relevant traits reduces suffering across populations.
The genetics of farmed salmon shapes the welfare trajectory of every fish hatched from those lines. Selection purely for rapid growth has produced fish that grow fast but are more susceptible to welfare-compromising conditions including cataracts, spinal deformities, and immune compromise. Including welfare traits - disease resistance, skeletal integrity, immune function, and stress response parameters - in breeding indexes creates fish better equipped for welfare-positive lives in farming conditions. The Norwegian breeding industry is beginning to incorporate these traits, recognizing that welfare and productivity are not inherently opposed.