Pre-slaughter welfare for farmed salmon involves crowding stress, asphyxiation risk, and the critical importance of effective stunning before killing.
Pre-slaughter welfare for farmed salmon is one of the most tractable welfare improvements in aquaculture, yet also one of the most inconsistently implemented. Effective stunning results in immediate unconsciousness that eliminates the suffering of the slaughter process. Poorly calibrated electrical stunning — too low a current, incorrect electrode placement — results in apparently stunned but conscious fish. The commercial pressure to process salmon as quickly as possible creates incentives to compromise on stunning effectiveness. Third-party verification of stunning effectiveness using brain-based indicators rather than behavioral responses (which can be confounded by muscle paralysis) is the standard regulators and welfare-conscious producers should adopt.