Salmon smolt production in hatcheries is a critical stage of both aquaculture and conservation stocking, with specific welfare challenges around density, disease, and developmental stress.
Smolt welfare during hatchery production affects both aquaculture output and conservation stocking success. Stress during the critical smoltification window impairs osmoregulatory capacity, immune function, and migratory behaviour, reducing survival after transfer to seawater. Best practice hatchery management maintains optimal water quality, appropriate stocking densities, structured enrichment to maintain behavioural competence, and careful timing of transfer to align with optimal smoltification status. These welfare improvements simultaneously improve production efficiency and conservation stocking outcomes, creating aligned incentives for welfare-positive management.