Pacific salmon hatcheries supplement declining wild populations but raise welfare questions about rearing conditions and the genetic and ecological impacts on wild fish.
Hatchery salmon welfare is often secondary to production objectives. High-density rearing causes fin erosion, aggression, and stress in fish whose welfare deserves consideration as sentient vertebrates. The stress of crowding, artificial food delivery, and transfer events reduces immune function and increases disease susceptibility. Welfare-conscious hatchery management reduces stocking density, uses naturalistic feeding regimes, provides structural complexity in rearing environments, and monitors behavioral indicators of stress rather than relying solely on survival and growth metrics.