Crowding stress in rainbow trout causes well-documented physiological and behavioural welfare impacts. Research into optimal stocking density reveals trade-offs between welfare, production efficiency, and farm economics.
Crowded rainbow trout experience chronic physiological stress that compromises immunity, healing, and normal behaviour. While higher densities improve economic efficiency of water and space use, the welfare costs to individual fish are substantial. Identifying density thresholds where welfare costs outweigh economic benefits is an important research priority.