Salmon hatcheries produce billions of juveniles annually, but crowding, disease, and stress in artificial rearing facilities raise significant welfare concerns before fish even reach the wild.
Hatchery environments subject salmon to chronic stressors including overcrowding, artificial lighting, and monotonous conditions. These conditions impair immune function, increase cortisol, and lead to abnormal behaviors. Fish raised in barren tanks lack the environmental stimulation needed for normal development, and the trauma of release into the wild following a lifetime in artificial conditions creates additional stress.