MICROBENTHOS ORGANISMS IN OWAN RIVER, EDO STATE, NIGERIA.

ABSTRACT

An investigation on the macrobenthic invertebrates of Owan River was carried out from July to September 2021 from three stations to assess the environmental impacts associated with the macrobenthic fauna  community.  Water  chemistry  samples  were  collected  on  monthly  basis  while,  benthic macrofauna  was  sampled  fortnightly  by  using  the  Ekman  Grab  for  shallow  water  bodies.  The estimated values for pH, conductivity, dissolved oxygen and biological oxygen demand were within the range of most tropical freshwater bodies. A total of 9 taxa (species) from 4 genera comprising 108 individuals were collected from the study area. The dominant groups were Ephemeroptera and Hempitera, while Coleoptera and Odonta constituted the rare groups. Taxa  richness  was highest  at  Station 1  (4.41)  and least  at  Station  2  (1.75). While, evenness values ranged from 0.79 at Station 1 to 0.97 at Station 2 and relative abundance was least (31.82%) at Station 2 and Station 3 and highest (36.36%) at Station 1.  Low number of taxa and individuals were recorded for the study period.