The method of killing farmed salmon at slaughter has significant welfare implications. Research on fish pain and consciousness has driven improvements in stunning requirements across major salmon-producing nations.
Slaughter welfare for farmed salmon received little attention until the evidence for fish pain and consciousness became too strong to ignore. Fish can regain consciousness rapidly after inadequate stunning, meaning poor slaughter technique causes a period of awareness during killing. CO2 narcosis — still used in some facilities — has been shown to cause avoidance behavior and distress responses before unconsciousness. Better alternatives include percussive stunning (a blow to the head causing immediate unconsciousness) and electrical stunning, both of which can achieve rapid loss of consciousness when properly applied. Consumer demand for certified products with higher welfare standards at slaughter is the most effective driver of industry change.