Biodiversity of fishes of Tagwai reservoir, Minna, Niger state, Nigeria

Abstract The biodiversity of the fishes of Tagwai Reservoir, Minna, Niger State, Nigeria was conducted for a duration of four months (January-April 2018). A set of experimental gill nets comprising nine multifilament nets of stretched meshes 25.4 mm, 38.1,50.8, 63.5, 76.2, 88.9, 101.6, 127.0 and 177.8 mm were used to sample the shore, surface and bottom water habitats of the reservoir. Seven species of fish belonging to five families were recorded. The most dominant fish family by number was Cichlidae, with two species Tilapia zillii (17.95 ± 4.43) and Chromidotilapia guntheri guntheri (4.91 ± 1.47) followed by Characidae with species Alestes macrolopidotus (2.11 ± 0.45), Mochokidae family with Synodontis vermiculatus (1.63 ± 0.27), Claridae with two species Clarias anguillarias (0.60 ± 0.11) and Clarias albopunctatus (0.75 ± 0.25), and, Family Hepsetidae with species Hepsetus odoe (1.16 ± 0.30). Bottom water habitat shows the presence of all the fish families with their species, while the shore and surface water habitat harbour species Tilapia zilli and Chromidotilapia guntheri guntheri of family Cichlidae, Synodontis vermiculatus of family Mochokidae and Alestes macrolopidotus of family Characidae. The study revealed that species Hepsetus odoe of family Hepsetidae, and species Clarias anguillarias and Clarias albopunctatus of family Claridae were only present in the bottom water habitat of Tagwai reservoir. Kwata Bello sampling station recorded the highest population (15.18 ± 1.56) of fish catch during the sampling period, while the least catch of fish population (3.18 ± 0.32) was recorded at Kwata Birgi sampling station. The family Cichlidae with population (22.86 ± 2.86) has the highest distribution in the reservoir. This indicates that Tagwai reservoir has therefore become unique compared to most other tropical man-made lakes and reservoirs in Africa, where Cichlids dominate the fishery soon after impoundment.