Aquaculture

Farmed Salmon Crowding and Stress Hormones

Crowding triggers measurable physiological stress responses in farmed salmon, with cortisol and glucose as key biomarkers of acute distress.

Key Facts

Cortisol levels in salmon spike within minutes of crowding events
Chronic crowding suppresses immune function and increases disease susceptibility
Pre-harvest crowding for grading and harvesting is a major welfare challenge
Crowding duration of even 30 minutes can cause lasting physiological effects
Monitoring cortisol and blood lactate provides objective welfare assessment

Welfare Considerations

Crowding causes both acute suffering and chronic stress-related disease. Minimising crowding frequency and duration is essential for salmon welfare.

What You Can Do

Minimise crowding events during routine husbandry
Develop harvesting protocols that reduce crowding time
Support welfare indicators based on physiological stress markers
Advocate for crowding welfare standards in salmon certification schemes