The hours and days before salmon slaughter involve crowding, food withdrawal, and transport stress that significantly affect welfare. Improving pre-slaughter management reduces suffering for millions of fish.
Pre-slaughter management for salmon involves a sequence of welfare insults culminating in slaughter. The cumulative effect of starvation, crowding, pump transfer, transport, and the slaughter environment itself represents significant suffering concentrated into the final hours of life. For fish that may have been well-managed throughout their growing period, pre-slaughter conditions represent a final welfare failure. Starvation stress, while partly necessary for product quality, can be minimized in duration. Crowding protocols can be designed to minimize oxygen depletion and physical injury. Slaughter method choice is the most significant welfare variable - the difference between properly implemented electrical stunning and CO2 or bleed-out without stunning is substantial in terms of suffering caused.