Pre-slaughter welfare for farmed Atlantic salmon involves crowding, handling, and transport stresses that cause significant suffering, with emerging standards seeking to improve conditions in the final production phase.
The pre-slaughter phase for farmed salmon concentrates multiple welfare harms in a short period. Crowding during harvest causes fin injuries, scale loss, and oxygen depletion. Transport to processing plants adds handling stress and potential temperature shock. At slaughter, the stunning method used determines whether fish experience a painful death — CO2 narcosis, formerly widespread, causes aversive gill irritation before insensibility, while percussive stunning can induce near-instantaneous insensibility. The scale of salmon farming — billions of fish annually — means that improvements in pre-slaughter welfare standards have enormous aggregate impact. Consumer pressure and retailer requirements are key drivers of improvement in salmon welfare standards, as aquaculture companies respond to market incentives.