Welfare science of crowding during salmon harvest operations, covering the stress physiology of pre-slaughter crowding, behavioral indicators of welfare compromise, and best practice crowding protocols.
Harvest crowding represents one of the most acute welfare events in the entire salmon production cycle — a brief period of extreme stress that affects potentially thousands of individual fish simultaneously. The commercial pressure to crowd fish rapidly for efficient transfer conflicts directly with welfare-based protocols that require limiting crowding duration and maintaining water quality. The alignment between welfare and flesh quality — stress before slaughter directly reduces product value — creates a rare case where economic incentives support welfare improvement. Best practice crowding protocols that minimize duration, maintain oxygenation, and enable rapid transfer to pre-stun stunning prior to slaughter substantially reduce the welfare harm of this unavoidable harvest operation. Certification schemes should include crowding protocol standards as a core welfare requirement.