STUDIES ON THE ICHTHYOFAUNA OF ADOFI RIVER, NIGER DELTA, NIGERIA

Fish species composition, distribution and abundance of Adofi River in Niger Delta, Nigeria were studied from June 2023 to May 2024. The river was divided into two sampling stations and 58 species of fish belonging to 23 families and 35 genera were recorded. Twenty species were ubiquitous in the study stretch. Eight and thirty species were restricted to station 1(upstream) and station 2 (downstream) respectively. The Schilbeid; Schilbe intermedius was the most abundant species as it contributes more than 10% by number of the entire fish caught. The families; Mochokidae, Schilbeidae, Cichlidae and Mormyridae dominated the fish populations of the river contributing more than 50% of the total catch and each having 9, 4, 7 and 10 species respectively. Gear selectivity of the fish species in the river shows the following trend; dragnet (49.2%), gill net (37.9%), hand net (6.5%) and hook and line (6.4%) of the total fish caught. All diversity indices showed a progressive increase from station 1 (upstream) to station II (downstream). The ichthyofauna of Adofi river compares favourably with other rivers of similar status within the Niger Delta and elsewhere. The differences observed in the fish species composition and distribution along longitudinal gradient of the river could be attributed to the prevailing hydrographic and physico-chemical differences between the stations as well as varying anthropogenic activities along the stretch.