Pre-harvest crowding of farmed salmon is a significant welfare challenge. The stress of concentration and transport before slaughter represents avoidable welfare harm that can be substantially reduced.
Pre-harvest salmon welfare involves a cascade of stressors in the final days of life. Extended feed withdrawal causes hunger and potentially immunosuppression. Progressive crowding into smaller enclosures prevents normal schooling behavior and increases inter-fish contact and competition. Well boat transfer involves capture, handling, and transport stress. The pre-slaughter holding period in processing facility tanks adds another period of confinement in unfamiliar environments. Each of these stressors individually causes measurable welfare harm; their combination creates a significantly negative welfare experience in the final days. Reducing the duration of each stress event, minimizing handling incidents, and implementing effective stunning immediately upon delivery to processing reduces the welfare burden of the harvest phase.