Crowding during salmon harvest is one of the most acute welfare events in the production cycle, with high-density crowding causing cortisol stress responses and oxygen depletion.
Harvest crowding welfare represents the most intense and concentrated welfare event in the salmon production cycle — thousands of fish experiencing extreme crowding for extended periods before slaughter. The welfare harm from crowding includes acute stress from density, oxygen depletion if water is not maintained, physical injury from crowding-induced contact and abrasion, and the physiological compromise that reduces welfare of surviving fish before stunning. Welfare-optimized harvest systems maintain oxygenated water throughout crowding, minimize crowding duration, use equipment calibrated to minimize scale loss, and transition fish rapidly from crowding to stunning. The welfare case for reducing the duration and intensity of pre-harvest crowding is compelling given the acute stress involved.