Measuring fish welfare in smallholder aquaculture: development and application of a welfare practice index in southern Nigeria

Fish welfare is increasingly recognised as a critical dimension of sustainable aquaculture, yet empirical data from smallholder systems in sub-Saharan Africa remain scarce. This study provides the first quantitative baseline of welfare practices, risk factors, and management behaviours among clustered aquaculture farms in southern Nigeria-a region contributing substantially to West African fish production. Between March and April 2025, structured questionnaires were administered to 188 farms within Camp 74 (Delta State), Uteh (Edo State), and smaller independent farms in Imo and Delta States. Data on farm characteristics, welfare awareness, feeding and stocking practices, water-quality management, mortality, and climate impacts were analysed descriptively and statistically. A composite Welfare Practice Index (WPI) classified farms as low, medium, or high in welfare performance, and chi-square tests identified key determinants of compliance. Most farms operated below optimal standards: 55.9% were low, 34.9% medium, and only 9.2% high on the WPI. Major risks included slow growth (91%), poor water quality (60%), and high mortality (56%). Water management was largely reactive-68% of farms changed water only when visibly necessary, and fewer than 5% conducted routine testing. Flooding was the most frequent climate-related cause of fish loss. Training and digital or hybrid record-keeping significantly predicted improved welfare compliance (p