Pre-slaughter handling and stunning of farmed salmon has significant welfare implications given evidence for fish pain and the scale of salmon aquaculture.
Farmed salmon pre-slaughter welfare has received increasing scientific attention as evidence for fish pain and stress responses has strengthened. Current industrial practice often involves CO2 stunning, which research shows causes aversive responses in fish before unconsciousness - essentially causing distress before death. Percussive stunning methods that render fish immediately unconscious are more humane but require investment in equipment and staff training. The scale of salmon slaughter - hundreds of millions annually - means improving stunning welfare would affect extraordinary numbers of individual animals.