Atlantic salmon spend their first years in hatchery environments before sea transfer. The welfare conditions in hatcheries significantly affect smolt quality, subsequent sea performance, and overall welfare outcomes.
Hatchery welfare establishes the welfare baseline for salmon that carry the physical and physiological consequences of their rearing environment into sea water. Smolts from high-density, low-enrichment hatchery environments enter sea cages with compromised immune function, reduced behavioural competence, and chronic stress physiology. These welfare costs compound over the sea water growing phase, contributing to reduced disease resistance and higher sea lice susceptibility. Hatchery welfare improvement - through reduced stocking density, improved environmental conditions, and early enrichment - has downstream benefits for sea water welfare outcomes. The investment in better hatchery welfare therefore has multiplicative welfare benefits across the entire production cycle.