Aquatic

Pre-Slaughter Crowding Stress in Farmed Salmon

The crowding and pre-slaughter period for farmed Atlantic salmon causes acute stress and requires careful management to minimise welfare impacts.

Key Facts

Pre-slaughter crowding concentrates salmon at densities far above production stocking rates
Crowding causes oxygen depletion, scale loss, and elevated cortisol in salmon
Fasting before slaughter is necessary but prolonged fasting causes hunger stress
Well-designed crowding systems minimise turbulence and maintain oxygen levels
Transition from cage to processing can take several hours during which fish welfare must be maintained

Welfare Considerations

The pre-slaughter phase represents one of the most acute welfare impacts in salmon production. Fish concentrated in crowding nets experience depleted oxygen, physical injury from collisions, and extreme stress responses. Welfare-positive pre-slaughter protocols minimise crowding time, maintain oxygen supplementation, and reduce handling. Better monitoring and standardised protocols could significantly improve welfare in this critical period.

What You Can Do

Support aquaculture certification schemes that include pre-slaughter welfare standards
Choose salmon from producers with documented pre-slaughter welfare protocols
Advocate for mandatory welfare monitoring during slaughter in aquaculture legislation
Support research into reduced-stress pre-slaughter systems for salmon
Encourage investment in in-water slaughter systems that avoid crowding stress