Evaluating the Impact of Water Quality on Zooplankton Assemblages of Mbo and Eastern Obolo Estuary, South-Eastern, Nigeria

The study evaluates the impacts of water quality on Zooplankton assemblages of Mbo and Eastern Obolo estuaries, Southeastern Nigeria. This was to determine the productivity levels and assemblage regarding the impact of water quality. Zooplankton species belonging to eight (8) phyla were collected across the samples stations during the dry and wet seasons using a fifty five (55) micrometer hydro-bioplankton net mesh size and were preserved in 4% formalin. The eight (8) phyla of zooplankton collected were; Copepoda, Rotifera, Cladocera, Gastropoda, Protozoa, Polychaeta, Chordata and Lamellibranchia in the two estuary which are Mbo and Eastern Obolo estuary. Three (3) stations from Mbo were Ibaka port, Ewang and Ebughuo creek mouth while the three (3) in Eastern Obolo were Iko jetty, Iko estuary mouth and Etizar. Higher species richness and Shannon-wiener index were recorded in station Ewang in Mbo as 30(S) and 3.25(H’) respectively, while the lowest species richness and Shannon wiener observed at Iko Estuary mouth as 27(S) and 3.11(H’) respectively. Physicochemical parameters such as water temperature, salinity, pH, total dissolved solids (TDS) and dissolved oxygen shows a seasonal variation between the dry and wet seasons. Redundancy analysis (RDA) and Pearson’s correlation analysis revealed a significant relationship between water temperature and Canthocampus staphylinus (p < 0.05), Gastropus sp (p < 0.01) and Euchlanis sp (p < 0.05). The spatiotemporal variability of water quality directly affect the zooplankton abundance and assemblages of the sampled stations especially in the wet season.