The smoltification process, during which juvenile salmon transition from freshwater to seawater rearing, represents a major welfare challenge in Atlantic salmon aquaculture.
Smoltification is one of the most stressful periods in farmed salmon's lives. The physiological demands of the transformation are enormous, and poor management during this period compounds stress with handling injuries, crowding, and inappropriate timing. Fish that enter sea cages before physiological readiness suffer severe osmoregulatory failure. Welfare standards requiring behavioural assessment of smolt readiness, gentle handling protocols, and gradual environment transitions dramatically improve outcomes and represent the minimum requirement for ethical salmon farming.