Decades of selective breeding in Atlantic salmon aquaculture have created domesticated strains with improved growth but potential welfare trade-offs in immune function and stress response.
Selective breeding for production traits in Atlantic salmon has generally improved biological performance but has not historically prioritized welfare traits directly. The relationship between rapid growth, metabolic stress, and immune function is complex — some evidence suggests that selection for extreme growth rates may compromise immune capacity in a manner analogous to fast-growing broiler chickens. Incorporating welfare-relevant traits — disease resistance, sea lice susceptibility, and stress reactivity — into breeding objectives represents an important opportunity to improve welfare across the entire production system through genetics. Wild salmon genetic integrity is an additional welfare-relevant concern, as introgression of domesticated traits into wild populations can reduce wild fish fitness and welfare through disruption of locally adapted traits.