Atlantic halibut is one of the world's largest flatfish and a premium aquaculture species in Norway and Scotland. Its complex welfare needs — including metamorphosis, cannibalism risk, and slaughter — require specialised management.
Atlantic halibut presents distinctive welfare challenges at every life stage. During larval development, the metamorphic transition is a period of high vulnerability when poor nutrition or environmental disturbance causes abnormal development and mass mortality. Early juvenile cannibalism creates a welfare crisis that requires careful density management and size-grading, though grading itself is a stressful intervention. In grow-out systems, halibut respond poorly to overcrowding and handling — elevated cortisol responses are well-documented following netting and grading events. The flatfish body plan creates specific slaughter welfare challenges: percussive stunning must be precisely applied to the small cranial area visible in a flat-lying fish, and electrical stunning geometry differs from round-fish species. Despite the small scale of production relative to salmon or tilapia, the high individual value and long grow-out period of halibut creates economic incentives for producers to invest in welfare improvements that avoid mortality and quality losses.