Harvest crowding - concentrating salmon before slaughter - is a high-intensity welfare event causing physiological stress, injury, and sometimes mass mortality. Improving harvest protocols is a high-impact welfare intervention.
Harvest crowding is one of the most intensive welfare events in the salmon production cycle. The rapid compression of fish into extremely high densities creates acute physiological stress - cortisol levels spike dramatically, heart rates increase, and oxygen competition begins. Fish unable to maintain normal position in crowded pens are pushed against each other and against net surfaces, causing scale and fin damage. The stress begins before the actual slaughter and compounds the welfare cost of the killing process itself. Research shows that even brief pre-slaughter crowding elevates stress indicators that persist through stunning, affecting meat quality as well as welfare. The alignment between welfare improvement (reduced crowding) and production value (better meat quality) creates an economic incentive for harvest protocol improvement.