Fish assemblage and diversity in Erinle reservoir, Osun State, Nigeria

Abstract

The fish assemblage in Erinle reservoir was investigated to know the status and proffer necessary management procedures for sustainability. Three points (A, B, C) were randomly selected on the reservoir and measured for physical and chemical parameters and fish species from October 2019 to August 2020. Fish species from fishermen landings were identified using field guides and abundance recorded by family and species. Physical and chemical analysis were measured insitu and the mean values for temperature (17.07 ± 0.72oC), dissolved oxygen (2.83 ± 0.31mg/L) and pH (5.55 ± 0.11) were below the recommended limits and significant (P<0.05) while ammonia was high (0.1 ± 0.03mg/L. A total of 213 individuals belonging to 15 species, with cichlids the most abundant family (58.2%) was identified. C. mariae was the most abundant species (18.8%) and May was the most abundant month (18.8%). Species richness (S) was 15, Shannon -Weiner diversity (H) was 3.56, and Evenness (E) was 5.74. It was observed that the fish abundance was low, diversity was high, and fairly evenly distributed despite the size of the reservoir, and wastes from human activities affected the physical and chemical parameters. It is therefore important to preserve biodiversity by ensuring and enforcing a clean environment.