Total hydrobiological studies of Okhuaihe River, Benin City, Southern Nigeria: Zooplankton fauna

Abstract

In a preliminary investigation of the zooplankton community of Okhuaihe River, Edo State, Nigeria, a total of 515 individuals comprising seventeen taxa were encountered in the river during the study period. Abundance was highest at station 3 (low flow rate) contributing 32.62% and lowest at station 1 (fast flowing) which accounted for 8.16% of total individuals. The overall abundance was significantly different at the four stations (P<0.05). An a posteriori Duncan Multiple Range (DMR) test showed that abundance at station 1 was significantly lower than those of the other stations (P>0.05). The copepoda dominated (53.98%) the samples followed by cladocera (44.29%) and then rotifer (1.75%). The most important taxa were Thermocyclops negletus, mesocyclops sp, Pleuroxus similis, Alona exima and Moina micrura. The taxon richness was highest in station 2 and lowest in station 3. Shannon diversity (H’) and evenness (E) were not significantly different (P>0.05) among the study stations.