TYPES AND ABUNDANCE OF ARTHROPOD FAUNA IN RELATION TO PHYSICO-CHEMICAL PROPERTIES OF THE BOTTOM SEDIMENT OF WARRI RIVER, NIGERIA

The occurrence of arthropods associated with the bottom sediment of Warri River was investigated, and samples were collected from January 2002 to May 2003. The values of pH, alkalinity, magnesium and total hardness were significantly different (P < 0.01) between the study stations, while organic matter recorded for the bottom sediment shows no significant difference (P>0.05). The dominant fauna were Dipteran larvae, which constitute 90.47%. Two rare groups of fauna (Arachnida and Ephemeropterans) were restricted to the upstream (Agbarho) station. Megapus sp. had a single record and is being recorded for the first time in Nigerian water bodies. All the organisms did not show any correlation with pH, conductivity and percentage (%) organic matter. Fauna densities were maxima only in the dry season period.