Abundance and Distribution of Fish Species in Ureje Reservoir Ado Ekiti, Ekiti State.

ABSTRACT This study assesses the abundance and distribution of fish species in Ureje Reservoir, Ado, Ekiti State, with a focus on species composition, population density, environmental influences, and human impacts on the ecosystem. Data analysis reveals the dominance of the family Cichlidae (95.85%), particularly Sarotherodon melanotheron (73.65%), highlighting their adaptability to varying aquatic conditions. Water quality parameters, including pH (8.55–8.75), conductivity (82.00–88.00 µS/cm), and nitrate concentration (0.81 mg/L), align with findings from other tropical reservoirs and influence fish community structure. The study identifies human activities such as agricultural runoff as contributors to water chemistry variations, impacting fish distribution. The low abundance of species like Clarias gariepinus and Parachanna obscura suggests habitat constraints and interspecific competition. The findings emphasize the need for , habitat restoration, and continuous water quality monitoring to maintain ecological balance and sustain fish productivity. Implementing sustainable fisheries management practices will enhance species diversity and ensure the long-term viability of the reservoir ecosystem. The study confirms the dominance of the family Cichlidae (95.85%) in Ureje Reservoir, with Sarotherodon melanotheron accounting for 73.65% of the total fish population.Oreochromis niloticus was also present but at a lower proportion (17.57%), compared to its higher abundance (>25%) in Kainji Lake. Other families, such as Clariidae and Alestidae, were underrepresented. Turbidity: 0.10–0.20 NTU (indicating clear water suitable for visual feeders like cichlids).pH: 8.55–8.75 (slightly alkaline, supporting cichlid growth).Conductivity: 82.00–88.00 µS/cm (within tropical freshwater limits).Nitrate concentration: 0.81 mg/L (supporting phytoplankton growth).Chloride concentration: 46.68 mg/L (higher in the lower section, indicating possible anthropogenic influence). Temperature: 27.55–27.70°C (stable and optimal for tropical fish metabolism and reproduction). Fish concentration in the lower reservoir section (20.95%) aligns with findings that nutrient accumulation supports higher productivity. The rarity of Clarias gariepinus and Parachanna obscura is consistent with studies indicating their specific habitat needs and susceptibility to overfishing.