Genetically improved tilapia strains dominate global aquaculture. The welfare implications of intensive breeding and farming practices deserve greater scrutiny.
Intensive tilapia farming raises welfare concerns around stocking density, water quality, and the effects of selective breeding for extreme growth rates. GIFT-strain tilapia grow so rapidly that skeletal deformities and internal organ stress have been documented in some high-performance lines. Stocking densities in intensive systems can reach 50-100 kg per cubic metre — far higher than conditions that allow natural behaviour expression. The sex reversal process, using methyltestosterone to produce all-male populations, involves exposure to endocrine-disrupting hormones. While tilapia are relatively stress-tolerant, they still exhibit cortisol responses and behavioural changes under poor conditions. Better welfare practices — lower stocking densities, good water quality management, and careful genetics selection — are achievable without sacrificing productivity.