Selective breeding programs for Atlantic salmon have dramatically improved growth and disease resistance but have also created welfare tradeoffs that require ongoing management.
Salmon selective breeding represents a microcosm of the welfare-production tradeoff inherent in animal agriculture. Dramatic growth rate improvements have reduced the time fish spend in sea cages before slaughter, potentially reducing cumulative welfare exposure. However, the genetic architecture of fast growth has in some cases brought correlated welfare harms including higher rates of skeletal deformities that cause chronic pain and impaired swimming. Cataracts develop in a significant proportion of farmed salmon, impairing vision and potentially affecting behavior and welfare. Breeding programs that incorporate welfare traits - including reduced aggression, skeletal integrity, and disease resistance - alongside production metrics represent an opportunity to align economic and welfare goals over successive generations.