Assessment of Fish Biodiversity in Oni River, Ogun State, Nigeria

For the purpose of sustainable exploitation of the fishery resourcesof Oni River, Ogun State, Nigeria, the fish biodiversity assessment was carried out. This was conducted by enumerating and identifying fish species composition, measuring the fish length, fish weight, assessing the fish abundance and biomass, determining the length-weight relationships and the length-frequency of the fishes. Altogether, 592 fishes were sampled comprising twenty-eight (28) species belonging to sixteen (16) families. The families identified included: Cichlidae, Mormyridae, Clariidae, Channidae, Malapteruridae, Gymnarchidae, Bagridae, Mochokidae, Polypteridae, Pantodontidae,Schilbeidae, Anabantidae, Osteoglossidae, Characidae, Notopteridaeand Distichodontidae. The family Mormyridae was the most abundant with 163 members followed by Cichlidae with 161 members. The least represented family was Schilbeidae with only two (2) members. On the species level, Tilapia zillii had the greatest number of representation with seventy (70) members, followed by Oreochromis niloticus with fifty-eight (58) members.