Salmon Crowding Stress at Harvest

Harvest conditions in salmon aquaculture involve crowding and handling that cause acute stress. Improved methods are reducing suffering.

Key Facts

Salmon crowding during harvest causes rapid elevation of cortisol, the primary stress hormone
High crowding densities can cause oxygen depletion and physical injury from crowding
Fish may be crowded repeatedly during grading, lice treatments and transfer throughout their life
Crowding during harvest is especially acute as fish density reaches extreme levels
CO2 narcosis is used in some systems to sedate salmon before slaughter
Electrical stunning combined with pithing (brain destruction) is considered most humane for salmon
RSPCA Assured salmon standards require pre-slaughter stunning

Welfare Considerations

Salmon harvest represents a critical welfare point with significant potential for suffering through crowding, oxygen deprivation, and inadequate slaughter methods. Evidence for fish sentience and pain perception now supports treating harvest welfare as a serious ethical issue. Improvement is technically feasible - the challenge is industry adoption and regulatory requirements.

What You Can Do

Choose RSPCA Assured salmon which requires pre-slaughter stunning
Ask salmon suppliers about their pre-slaughter stunning protocols
Support regulatory requirements for mandatory salmon stunning before slaughter
Reduce salmon consumption and prioritise welfare-certified sources