Salmon slaughter methods significantly affect fish welfare. Evidence-based humane slaughter — percussion stunning before killing — dramatically reduces suffering compared to conventional methods like asphyxiation.
Salmon slaughter welfare is one of the clearest opportunities to dramatically reduce suffering in aquaculture at low cost. Traditional methods including CO2 immersion and simple asphyxiation cause prolonged distress as fish remain conscious during a slow death — CO2 immersion in particular causes a highly aversive acidic sensation before unconsciousness. Percussion stunning — a targeted blow to the head that causes immediate concussive unconsciousness — eliminates this suffering completely when properly applied. Combined with rapid spiking to destroy the brain, this two-stage method achieves the most welfare-friendly slaughter currently available at commercial scale. Industry adoption is driven by regulatory requirements and buyer standards — major retailers in Norway and the UK now require effective stunning, demonstrating that market-driven welfare improvement is achievable in aquaculture.