FISH SPECIES ABUNDANCE AND DIVERSITY OF RIVER UKE, NASARAWA STATE, NIGERIA

A study was conducted to assess fish species abundance and diversity of River Uke, Uke, Nasarawa State, Nigeria. Fish were sampled from three sites, upper (A), middle (B) and lower (C) courses of the river. The study lasted for ten months from June 2014 to March 2015. A total of two thousand, one hundred and twenty six (2,126) fish comprising of 7 families and 11 species were sampled. Seasonal fish abundance of River Uke revealed that average monthly catch in the wet season was 25 % lower than in the dry season. Cichlidae dominated the sampled fish families accounting for 26.20 % of total catch while Latidae was least abundant with 6.21 %. Monthly fish abundance was dominated by three species, namely, Clarias gariepinus (18.44 %), Tilapia zilli (14.44 %) and Oreochromis niloticus (11.76 %) all accounting for 44.64% of the total catch. The trend of monthly fish abundance also showed a bi–modal peak with the minor peak observed in March (260) and the major peak in November (292). Fish abundance by sites revealed individual catches of 671, 365 and 1090 in Site A, B and C, respectively. Total Shannon–Wiener Diversity index of River Uke in this study was 2.312 and the index values were generally higher in the wet season (except October) than in the dry season. Total Simpson Index calculated for River Uke in this study was 0.892. Keyword: Fish, species abundance, diversity, seasonal, River Uke.