Feeding Habit, Length–Weight Relationship and Condition Factor of Clarias gariepinus, Chrysichthys nigrodigitatus and Oreochromis niloticus in Aiba Reservoir, Osun State, Nigeria

Abstract

Understanding the biology and feeding ecology of freshwater fish species is essential for sustainable fisheries management and conservation of inland water ecosystems. This study investigated the feeding habits, length–weight relationships, and condition factor of Clarias gariepinus, Chrysichthys nigrodigitatus, and Oreochromis niloticus in Aiba Reservoir, Osun State, Nigeria. A total of 66 fish specimens were collected over six months and analysed using standard morphometric, biological, and stomach-content analytical procedures. Length–weight relationship parameters were estimated using least-squares regression analysis, while condition factor values were used to evaluate the physiological well-being of each species. Results revealed species-specific variations in morphometric characteristics, feeding habits, and reproductive conditions. All three species exhibited negative allometric growth patterns, indicating that increases in body length exceeded corresponding increases in body weight. Mean condition factor values were 0.94 ± 0.33 for C. gariepinus, 1.30 ± 0.23 for C. nigrodigitatus, and 1.01 ± 0.61 for O. niloticus, suggesting relatively favourable environmental conditions for growth and survival within the reservoir. Stomach-content analysis revealed active feeding across all species: O. niloticus exhibited omnivorous behaviour, C. gariepinus displayed carnivorous and opportunistic tendencies, and C. nigrodigitatus showed benthic and omnivorous feeding characteristics. Reproductive assessment identified immature, developing, mature, and spent gonadal stages, confirming active reproductive activity during the study period. These findings demonstrate that Aiba Reservoir supports fish growth, feeding, and reproduction, while providing baseline data for fisheries management, biodiversity conservation, and ecological monitoring in tropical freshwater ecosystems.