Environmental enrichment for farmed Atlantic salmon can reduce chronic stress and stereotypic behaviour in sea cage environments, improving welfare without major changes to production infrastructure.
The net pen environment offers little of the complexity of wild salmon habitat - no substrate to interact with, no current variation, no prey to pursue. Salmon deprived of environmental complexity show repetitive swimming that parallels stereotypies in terrestrial species. Relatively simple interventions - varied light environments, subsurface feeding that requires active pursuit, and appropriate current in recirculating systems - provide meaningful enrichment that reduces these indicators. Enriched salmon show lower stress indicators and better flesh quality, aligning welfare and production incentives.