Salmon slaughter methods vary widely in their welfare impacts. Improving stunning and killing practices in salmon aquaculture is one of the most impactful and tractable welfare improvements available to the industry.
Salmon slaughter welfare varies enormously between facilities. CO2 exposure causes a prolonged, distressing death as carbon dioxide acidifies gill tissue — fish show vigorous escape behavior before losing consciousness. Live ice slurry causes slow cooling during which fish remain conscious and experience cold stress. Percussive stunning, when correctly applied, renders fish immediately unconscious before bleeding. The scale of salmon production — hundreds of millions of animals annually — means that slaughter method improvements have enormous aggregate welfare impact. Consumer certification preferences and regulatory requirements are the primary drivers of industry adoption of better methods.