Crowding in salmon farming triggers hormonal stress responses measurable through cortisol. Understanding this physiology supports evidence-based density management.
Cortisol measurement provides objective evidence that crowding causes physiological stress in salmon. This stress response is both a welfare indicator in itself and a mechanism by which chronic crowding causes secondary welfare harm through immune suppression. Evidence-based density limits informed by cortisol science represent a welfare-improving application of aquaculture physiology research.