Effective stunning before killing is essential for fish welfare at slaughter, yet most aquaculture production globally occurs without any stunning requirement.
Stunning at slaughter is the single most impactful welfare intervention available for farmed fish at the point of death. Most farmed fish globally are killed without stunning, typically through asphyxiation in air or on ice, methods that cause prolonged distress. The scientific evidence that fish experience aversive states during slaughter is now sufficient to justify mandatory stunning requirements. Progress has been faster in Europe than elsewhere, driven by regulatory advances in Norway and UK retailer standards. The aquaculture industry initially resisted stunning requirements on cost and practicality grounds, but commercial-scale electrical and percussive stunning systems are now available and economically viable.