Cage aquaculture of Nile tilapia in tropical freshwater lakes and reservoirs is a major production system in Africa and Asia, with welfare challenges related to oxygen depletion, crowding, and disease in warm water environments.
Tilapia in cage aquaculture in tropical lakes face acute welfare risks from low dissolved oxygen events that cause mass suffocation. In eutrophic lakes where algal blooms are common, overnight oxygen crashes can kill entire cage contents within hours. Social dominance in tilapia means subordinate individuals may be excluded from food and suffer growth depression and chronic stress. Disease outbreaks in warm, densely stocked cages cause rapid spread and significant mortality. Welfare improvements require better cage siting, oxygen monitoring, disease surveillance, and management of social structure through appropriate stocking.