The pre-slaughter phase in salmon aquaculture involves crowding, fasting, and transport that cause significant acute stress. Improving this phase is one of the most impactful welfare interventions.
The pre-slaughter phase represents a concentrated period of welfare harm for farmed salmon. Fasting causes hunger and behavioral frustration. Progressive crowding as fish are concentrated for harvest eliminates behavioral space and oxygen. The pumping process that moves fish from pens to processing vessels causes physical trauma including scale loss. For salmon killed by CO2 exposure or live chilling, the process of rendering insensible takes minutes and is distressing. Electrical stunning when properly calibrated renders fish insensible almost instantly. The alignment between welfare and product quality — stressed fish have measurably lower-quality flesh — creates a commercial incentive for slaughter reform that welfare arguments alone may not achieve. This economic alignment makes pre-slaughter welfare a tractable target for industry improvement.