Stocking density and social management in Atlantic salmon farms significantly affect aggression, injury, and chronic stress that reduce welfare across the production cycle.
Crowding in salmon farms creates conditions where dominance hierarchies become more intense, and subordinate fish bear the welfare costs of chronic social stress. Fin erosion, eye damage, and scale loss from aggression are visible welfare indicators that increase with stocking density. Chronically stressed salmon have impaired immune function, reduced feed conversion, and higher disease susceptibility — welfare and production harms that compound each other. The economic pressure toward high stocking density must be weighed against the welfare costs and the disease risks that high density creates. Lower density production with better welfare outcomes is achievable and is rewarded by some premium market segments.