The crowding of farmed Atlantic salmon immediately before slaughter is a major acute welfare event that requires careful management to minimize suffering at the end of production.
Pre-slaughter crowding is one of the most acute welfare events in salmon farming. The combination of extreme density, handling stress, oxygen depletion, and conspecific aggression creates severe short-term suffering. Fish welfare during crowding can be improved by minimizing the duration between crowding and stunning, maintaining oxygen supplementation throughout, using well-boat systems with monitoring equipment, and training staff in fish welfare indicators. The welfare impact of pre-slaughter crowding is measurable in flesh quality through stress-induced changes in muscle pH, providing a product quality incentive aligned with welfare improvement.