Evaluation of fish exploitation in the Benin River stretch using the Catch Per Unit Effort (CPUE) analysis

Abstract

An assessment was carried out to investigate the species abundance by Catch Per Unit Effort (CPUE) in Benin River. Fish samples were collected for 21 months starting from April 2019 to March 2021 from four different stations of the Benin River. Abundance and biomass of fishes were used to estimate the CPUE. The gears used in fishing were baited hooks and lines in a set of seven. A total of 620 fish specimens were caught; 114(18.39%) in stations 1, 142 (22.29%) in station 2, 234 (37.74%) in station 3 and 130 (20.97%) in station 4. During the rainy season, 253 (40.81%) individuals were caught with a biomass of 4470257g and 367 (59.19%) individuals, with a biomass of 5322718 g during the dry season. Chi-square test showed significant difference (P<0.001) due to seasons. Shannon diversity index (H’) was highest in station 3 (2.394) and lowest in station 4 (1.994) while evenness index was highest in station 1 (0.5765) but lowest in station 2 (0.1586). Hutcheson’s t-test showed that the diversity of station 4 was significantly lower (P<0.05) than those of other stations, which are similar to each other. The CPUE comparison revealed that the highest was recorded in September in station 3 (2571 kg/boat/day) while the lowest (27 kg/boat/day) was in June in station 2. The study recommends further investigation on CPUE based on gear types in Benin River over a longer period (for the two seasons).