Dynamics of Zooplankton of Azuabie Creek in the Upper Bonny Estuary of the Niger Delta

Abstract: The dynamics of zooplankton community of Azuabie Creek in the Upper Bonny Estuary of the Niger Delta was studied over a one-year period from April 2006 to March 2007. Ten sites which included locations with sources of human and industrial pollutant inputs and relatively uncontaminated control points along the creek were chosen for the study. Water and plankton samples were collected monthly from each station using standard methods, followed by laboratory analyses. A total of 35 species of zooplankton belonging to eight major taxonomical groups were recorded during the study periods. Out of the total number, 20 species representing 57.14% belonged to the class copepoda; 2 species (5.71%) represented the class euphausiaceae; 1 species (2.86%) represented class spionidae; 2 species (5.71%) belonged to the class protozoa; 4 species (11.43%) belonged to the class cladocera; 3 species (8.57%) belonged to the class insecta, 2 species (5.71%) belonged to cumaceane while 1 species (2.86%) represented the class nematoda. In terms of abundance, the highest number of occurrence found was the class copepoda (88.95%), followed by cumacean (2.76%); cladocera (2.35%), protozoa (1.99%), spionidae (1.63%), insecta (1.28%); nematoda (0.76%) and euphausiid (0.26%). There were significant spatial and monthly (seasonal) differences (p<0.001), as well as interactions in the abundance of major zooplankton taxa. Community indices had significant differences between sampling locations and months, with the wet season months generally having higher species richness, diversity and evenness but lower dominance