Atlantic cod aquaculture has emerged as both a conservation and welfare concern, with the species having complex spawning behaviors and welfare challenges in high-density farming systems.
Cod welfare in aquaculture involves challenges specific to a species with complex schooling and spawning behavior. Aggressive competition at feeding — where dominant individuals monopolize food access, causing growth variation and injury to subordinate fish — is a significant welfare problem in high-density cod farms. Crowding stress impairs immune function, increasing susceptibility to parasitic sea lice and bacterial infections. The photoperiod manipulation used to control spawning timing disrupts natural behavioral cycles, and the welfare implications of this disruption are poorly understood. Cod aquaculture operations that achieve lower stocking densities, better feeding system design to reduce competition, and careful monitoring of injury rates show improved welfare outcomes, but industry economics push toward densities that compromise these improvements.