Genetic selection in farmed Atlantic salmon has produced fish that grow faster but may have reduced disease resistance, with welfare implications from the interaction between genetics and production conditions.
Salmon genetics welfare represents a challenging intersection of production optimisation and animal welfare. Selection for rapid growth has produced fish that convert feed efficiently and reach market weight quickly, but spinal malformations associated with rapid growth are a significant welfare concern causing chronic musculoskeletal pain in affected individuals. Cardiac conditions including heart and skeletal muscle inflammation are partly heritable and cause acute welfare crises. The welfare potential of genetic selection in the other direction - selecting for disease resistance, reduced malformation rates, and robustness - is substantial and increasingly incorporated into breeding programme objectives alongside production traits.