The smolt transition - transferring juvenile Atlantic salmon from freshwater to sea water - is one of the most welfare-critical moments in the salmon farming production cycle.
The smolt transition represents an acute welfare challenge combining physiological vulnerability with the stresses of handling and environmental change. Fish in active smoltification are particularly sensitive and poorly managed transfers cause mortality and prolonged post-transfer welfare compromise. The welfare-positive approach prioritises precise timing, minimised handling duration, careful water temperature management, and close post-transfer monitoring. Stocking density during transfer transport is a key controllable welfare variable that certification standards can and should address.