The crowding of salmon before slaughter is a standard production practice that causes significant acute welfare harm. Understanding and addressing this gap improves welfare at the most critical moment.
Pre-slaughter crowding is a welfare compromise that occurs in the final period of a fish's life - at the point when welfare is, if anything, most morally urgent. A salmon crowded at extreme density for two hours before slaughter experiences the physiological equivalent of a severe stress event: scale loss from physical contact (painful and impairing), hypoxia from competition for oxygen, and surging cortisol that alters physiology throughout the body. The welfare cost is real and measurable. Reducing crowding duration through operational efficiency improvements, maintaining adequate oxygenation during crowding, and minimizing the time between crowding and effective stunning are all achievable welfare improvements.