Fish community structure in a natural rainforest lake, Nigeria

Abstract

Studies on fish community of Agulu Lake were conducted from April to July 2015. Fish samples were bought from fishermen who caught them using gillnets and traps. A total of 159 fish samples belonging to 3 orders, 7 families, 8 genera and 10 species were obtained during the study. Station I had the highest fish abundance of 50.9 %, while station III had the lowest fish abundance of 23.5 %. Fishes belonging to the order Perciformes were the most abundant (66.04 %) of the total catch. This was followed by Siluriformes (31.43 %). The least order Osteoglossiformes was represented by 1.26 % of the total fish caught. Cichlidae, the most abundant family, has the highest number (103, 64.78%) of fish caught from the lake. The monospecific families encountered in the study were Channidae (Parachanna obscura), Bagridae (Chrysichthys nigrodigitatus), Mochokidae (Synodontis ocellifer), Malapteruridae (Malapterurus electricus) and Notopteridae (Papyrocranus afer). The highest number of fish was caught in May (52, 32.7 %) and the lowest number of fish was caught in July (28, 17.6 %). The general diversity index (H) was highest (0.741) in station I and lowest (0.605) in station II. Evenness (E) followed the same trend being highest (0.741) in station I and lowest (0.670) in station II. Dominance was maximum (0.342) in station II and minimum (0.270) in station 1. The same trend was observed in Simpson’s index which was highest (0.324) in station III and lowest (0.258) in station I.

Keywords: Fish community, Clariidae, Cichlidae, Channidae, Malapteruridae, Notopteridae, Rainforest, Agulu Lake