Selective breeding programs for farmed Atlantic salmon shape growth, disease resistance, and behavior with significant implications for individual fish welfare across production cycles.
The genetics of farmed salmon profoundly shape welfare outcomes at population scale. Selection pressure for rapid growth without corresponding welfare trait selection has contributed to higher prevalence of deformities, reduced disease resistance, and potentially altered stress reactivity in some strains. Progressive breeding programs now incorporate welfare indicators including deformity rate, stress cortisol response, and disease resistance directly into selection indices. This evolution in genetic strategy represents a meaningful shift toward using selective breeding as a welfare improvement tool rather than a potential welfare risk.