Assessing the current fish diversty and abundance of a tropical rainforest lentic freshwater ecosystem, South - Eastern Nigeria

This study investigated the fish fauna and species abundance of Oguta Lake in Imo state, Nigeria. Three sampling stations were selected based on factors such as depth, volume of water, accessibility and the various activities taking place in and around the lake. Fish samples were collected from three sampling stations for seven months. Analysis of variance (ANOVA) showed significant difference (p < 0.05) in the piscifaunal overall density in the three stations. Six families composed of eleven species were recorded. Cichlidae (52.1%), the most abundant family dominated the samples in the three stations. Cyprinidae (0.5%) was the least family encountered in the study. Tilapia zilli, the most abundant species occurred highest in station 3 (13.8%). The highest general diversity (0.885) occurred in station 3 while the least value (0.859) was obtained in station 1. Six fish families collected in this study compared to previous report of Nwadiaro (1989); and the low species abundance reveals that Oguta Lake is experiencing loss of biodiversity in terms of its fishery resources due to anthropogenic activities which affect the composition and structure of fish resident in lakes.