Pre-slaughter crowding during salmon harvest is a major welfare event. Refining crowding protocols, minimizing duration, and improving handling techniques significantly reduce stress.
Pre-slaughter crowding represents one of the highest-intensity welfare events in the salmon production cycle, with acute stress responses measurable through cortisol, behavior, and physiological indicators. The process is largely unavoidable with current technology but can be refined to reduce duration, density, and physical trauma. Oxygen supplementation during crowding is perhaps the single most impactful welfare improvement, reducing hypoxic stress in the final hours of life. Gentle pump systems with reduced impact forces decrease physical injury during transfer. Monitoring fish behavior and oxygen levels during crowding allows operator intervention when welfare thresholds are exceeded. The sequence of crowding, transfer, transport, and slaughter constitutes a continuous stressor chain — minimizing stress at each stage has cumulative welfare benefit for the final hours of life.