Atlantic salmon in intensive aquaculture experience crowding-related welfare problems including fin damage, aggression, chronic stress, and impaired immune function — measurable welfare costs of commercial production.
Atlantic salmon in commercial net pens exist in conditions that chronically frustrate territorial and spatial behavioral motivations. Crowding-induced aggression results in fin and body damage that serves as both a welfare harm and an indicator of the stressfulness of production conditions. The 10-20% mortality rate typical in commercial salmon farming reflects the cumulative welfare burden of disease, parasites, handling stress, and environmental challenges. Research suggests that reducing stocking densities and improving environmental enrichment can improve welfare outcomes and — importantly — also reduce mortality and improve production efficiency, making welfare improvement economically rational. The key challenge is translating research recommendations into regulatory minimum standards and effective monitoring.