Stocking density in fish farms directly affects welfare through crowding stress, competition for resources, and injury rates. Science-based density limits can significantly improve aquaculture welfare.
Stocking density is a key welfare lever in aquaculture that often reflects the tension between production efficiency and animal welfare. High-density systems maximize use of expensive infrastructure but create chronic stress conditions for fish. Crowded fish show elevated cortisol, increased aggression, fin damage, and increased disease susceptibility — all indicators of compromised welfare. The relationship between density and welfare is not simple, as water quality management can partially mitigate density effects, but there are limits. Welfare-positive aquaculture requires density limits informed by species-specific research and honest welfare assessment.