Welfare science for Atlantic salmon smolts during the critical parr-to-smolt transition, covering the physiological challenges of smoltification, stress impacts on transition success, and welfare management during transfer to seawater.
Smolt welfare represents a critical juncture in salmon aquaculture where poor management causes welfare harm during one of the most physiologically demanding transitions in fish biology. The smoltification process involves comprehensive physiological reorganization — endocrine, osmoregulatory, behavioral, and morphological — that requires welfare management to succeed with minimal stress. Crowding, handling, and water quality failures during this sensitive period compromise the transformation and increase post-transfer mortality and morbidity. Welfare best practice during smoltification includes verifying physiological readiness before transfer, minimizing handling events, optimizing transport water quality and duration, and providing recovery conditions after seawater introduction. The welfare investment in smolt quality pays dividends across the entire subsequent production period.