Assessment of Inbreeding Depression and Broodstock Management Practices in Catfish Farming in Lagos State, Nigeria

Abstract

This study assessed inbreeding depression and broodstock management practices among catfish farmers and hatchery owners in Lagos State, Nigeria. Structured questionnaires were administered to 265 respondents; data were analyzed using descriptive statistics, Chi-square tests, independent-samples t-tests, one-way ANOVA and Pearson correlation at p< 0.05. Most respondents (79.6%) sourced broodstock through purchase from other farms, 58.9% used multiple sources, and only 6.8% relied exclusively on own-farm stock. Nearly half (46.8%) used skewed sex ratios of four or more females per male. Effective population size (Ne) fell below the recommended threshold of 50 for most farms, with 67.2% recording an inbreeding rate above one percent per generation. Over 90% selected fast-growing "shooters" as breeding stock, while only 17.7% kept systematic breeding records. Farm scale, experience, education and record-keeping significantly predicted Ne category and management outcomes (p < 0.05). Mean Ne and the number of inbreeding-depression signs observed differed significantly by farm scale, shooter-selection practice, record-keeping status and education (p < 0.001). Broodstock holding size correlated positively with Ne (r = 0.684, p < 0.001), and Ne correlated negatively with the number of inbreeding-depression signs (r = –0.412, p < 0.001). Leading constraints were insufficient supply of genetically diverse catfish (74.7%) and lack of documentation (71.3%). The study concluded that broodstock management practices were significantly associated with inbreeding-depression risk, and recommended zonal broodstock banks, mandatory record-keeping and targeted extension services.