Abstract
Biodiversity is one of the most vital aspects of community organization and structure, its key elements are species richness and relative species abundance. Fish fauna of River Argungu was assessed for 12 months between the months of March 2014 – February 2015. A total of 3,209 fishes belonging to 62 species, 34 genera and 16 families were sampled using cast, clap and gill nets, traps, hooks and line. The most abundant family was Mormyridae with a percentage biomass of 70.31 % and Hyperopisus bebe occidentalis being the
most abundant species with biomass of 39.89 %, while the least was family Anabantidae with biomas of 0.03 % and Ctenopoma kingsleyyae being the only species. The biggest fish species caught was Bagrus filamentosus with a mean weight of 1105.00 g, while the smallest was Petrocephalus bane ansergie with mean weight of 6.00 g. The greatest diversity was observed during the month of July and October 2014 with a Simpson’s index of 0.08 (1-D = 0.92 and 1/D = 12.50) in both months, while the least was observed during the month of January 2015 with a Simpson’s index value of 0.77 (1-D = 0.23 and 1/D = 1.30). This study infers that, river Argungu is rich in fish fauna, however there is need to check indiscriminate human activities observed to be going on along the river bank.

Key words: Fish fauna, Argungu, Diveresity, Mormyridae, Anabantidae