Identifying and monitoring stress in farmed fish is fundamental to welfare assessment. A growing toolkit of behavioural, physiological, and environmental indicators allows farmers to detect and respond to welfare problems before they become severe.
Stress monitoring in fish aquaculture has developed from a research curiosity into a practical farm management tool. Water cortisol sampling allows farms to monitor population-level stress without catching individual fish. Camera systems with AI-assisted image analysis now detect abnormal swimming posture and schooling disruption in real time. Regular gill score and external lesion surveys provide cumulative welfare data that guides stocking density and management decisions. Welfare-positive farms set action thresholds — a defined level of fin damage or cortisol elevation that triggers a management response. This proactive approach contrasts with reactive intervention only when mortality rates rise.