Impact of some hydrological factors on biodiversity of fish in Agaie/Lapai dam reservoir of Niger State, Nigeria

Abstract

The effect of some hydrological factors (rainfall, inflow and depth of water) on fish biodiversity in Lapai dam reservoir were studied by monthly samplings and measurements taken from May, 2013 to October, 2014. This reservoir is situated at 90 39ˊ N latitudes and 60 33ˊ E longitudes located near Bakaje at the confluence of the Jatau River. Samples of fishes were collected from the fishermen in two chosen landing sites where they catch fishes using cast nets, seine nets and hooks and lines in designated locations of the reservoir. Eleven (11) fish families were identified during the study belonging to Brigridae with 2 species, Characidae with 2 species, Schilbeidae with 2 species, Cichlidae with 5 species, Claridae with 2 species Cyprinidae with 3 species, while Chanidae, Hepsetidae, Malapteruridae, Mochokidae and Mormyridae had 1 specie each respectively. The highest level of impact of rainfall was felt by the fish from the month of March to November. Cichlidae recorded the highest respond to the inflow of water from tributaries while other fish families showed no any increase or decrease in abundance to the changes of the flow-rates of water. The family of Mochokidae responded to the fall of water level (depth) while other families of fish were not significantly impacted by the factor.