Salmon aquaculture is one of the world's fastest-growing food production sectors, but its welfare record is complicated by disease, crowding, and handling stress.
Farmed salmon welfare is improving but remains problematic. Crowding causes chronic stress and disease transmission, especially sea lice (covered separately). Cataracts affect a high proportion of farmed salmon, impairing feeding behavior. Skeletal deformities from rapid growth cause chronic pain. Killing methods vary significantly in humaneness — live chilling (placing fish in ice slurry while conscious) is widely used but causes prolonged distress. CO2 stunning before killing is more humane but less common. Land-based recirculating aquaculture systems can address many welfare issues by controlling environment and preventing sea lice.