Atlantic cod aquaculture is being redeveloped in Norway following earlier commercial failures, with lessons learned about welfare challenges specific to this species in intensive production.
Atlantic cod welfare in aquaculture is challenged by their cannibalistic tendencies and sensitivity to handling stress. Cannibalism in size-heterogeneous groups causes injuries and mortality in smaller individuals. Grading to reduce size variation causes handling stress and physical injury. Photoperiod manipulation to delay sexual maturation involves sustained light exposure regimes that may conflict with natural biological rhythms. Bacterial and viral diseases including vibriosis and viral nervous necrosis (VNN) can cause high mortality and suffering in poorly managed systems. Cod are sensitive to dissolved oxygen levels and temperature, making water quality management critical to prevent chronic physiological stress.