Crowding is the primary welfare stressor in salmon aquaculture, causing measurable physiological and behavioral changes that compromise fish health and welfare.
Crowding in salmon aquaculture creates chronic stress that impairs immune function, increases aggression and injury, and reduces feeding behavior. The economic incentive to maximize biomass per cage conflicts directly with fish welfare. Welfare-positive certification schemes use stocking density limits as a primary standard, but many conventional farms operate well above recommended thresholds. Consumer demand for welfare-certified salmon creates market incentives for density reduction, demonstrating how purchasing choices directly affect individual fish welfare.