The effects of environmental parameters on zooplankton assemblages in tropical coastal estuary, South-west, Nigeria

The present study was carried out to examine the distribution and assemblage structure of zooplankton in relation to environmental parameters of tropical coastal estuarine ecosystem impounding Bight of Benin, Nigeria. The estuarine water samples were collected between January and December, 2014 from three sampling zones (Brushpark, Open water and Wetland) then were fixed in 4% formalin. A total of twenty-eight (28) species belonging to four (4) groups were recorded in this study. These groups were rotifera, copepoda, cladocerans and ostracodas, and were all widely distributed in the three investigated zones. Higher richness, dominance and abundance indices were recorded in Zone I when compared to both Zones II and III. Cluster analysis showed five distinct species communities. The canonical correspondence analysis (CCA) showed a distinct smattering positive and negative correlation on the distribution of zooplankton indicating that the relative abundance of any species was dependent on specific environmental variables.