How fish are killed in aquaculture significantly affects their welfare at end of life. Current practices vary enormously, with many causing prolonged suffering.
The scale of fish slaughter in aquaculture makes end-of-life welfare one of the most numerically significant animal welfare issues. Asphyxiation causes conscious distress for minutes — fish struggle to breathe and show pain behaviors until they lose consciousness from hypoxia. Ice slurry slows metabolism but does not induce insensibility before death begins. Percussive or electrical stunning that renders fish immediately insensible is practicable and is being adopted by higher-welfare producers.