The pre-slaughter phase for Atlantic salmon involves crowding from sea cages into harvest vessels, live transport, and then killing — typically by percussion or electrical stunning followed by bleeding. Each stage carries specific welfare risks that welfare-conscious producers are working to mitigate.
Atlantic salmon crowded into well-boats for transport experience the acute stress of rapid density increase, potentially lasting hours before slaughter. Oxygen depletion in crowded conditions causes hypoxic stress responses. Percussion stunning must achieve immediate insensibility — inadequate application causes fish to regain consciousness before death. The welfare gap between best and worst practice in salmon slaughter is large: fish killed by asphyxiation may experience up to 9 minutes of air exposure consciousness, while electrically stunned fish achieve insensibility within a second. Consumer demand for high-welfare certified salmon has driven significant investment in stunning technology across Norwegian and Scottish industries.