Aquaculture

Farmed Salmon Pre-Harvest Crowding Welfare

The pre-harvest crowding period in salmon aquaculture causes acute stress and welfare compromise that is among the most significant events in the production cycle.

Key Facts

Pre-harvest crowding increases stocking density by 3-5 fold as fish concentrate before lifting
Crowding causes oxygen depletion, increased aggression, and fin damage
Crowding prior to slaughter can last minutes to hours depending on system and scale
Welfare indicators including respiration rate and loss of equilibrium worsen during crowding
Novel crowding assessment methods allow real-time welfare monitoring during the process

Welfare Considerations

Pre-harvest crowding is an acute welfare event that causes measurable stress and physical harm. Minimising crowding duration and density, maintaining oxygen levels, and developing real-time welfare monitoring reduce suffering during this unavoidable phase.

What You Can Do

Support certification schemes with pre-harvest welfare monitoring requirements
Advocate for maximum crowding duration standards in salmon welfare guidelines
Choose salmon from producers demonstrating pre-harvest welfare management
Encourage research into crowding welfare assessment methods