This study was carried out between June 2019 and January 2020 within which plankton samples were collected in the wet and dry seasons, for four months and across four stations of the Creek. Samples for Phytoplankton analysis were collected by obtaining 1litre of the water sample fetched 5 cm below the surface at each sampling station. Whereas samples for Zooplankton analysis were obtained by straining 50 liters of water through a plankton net of (55 µm). both samples for Phytoplankton and Zooplankton analysis were preserved with 4% formalin in which a few drops of Rose Bengal stain had been added. Measurement, Identification, and Counting of plankton species were carried out in the laboratory using standard methods, equipment, and checklists. A total of 16 species of Phytoplankton belonging to 4 classes and 21 species of Zooplankton belonging to 7 classes were encountered and identified during the study periods for all stations, months, and seasons. The result shows that BACILLARIOPHYCEAE was the most abundant Phytoplankton class with a percentage composition of 42% and 44% in wet and dry seasons respectively. Whereas, CHLOROPHYCEAE and CYANOPHYCEAE had a percentage composition of 37% and 15% for the wet season and 24% and 17% for the dry season. EUGLENOPHYCEAE had the lowest percentage of 6% and 15% for wet and dry seasons respectively. Crucigenia sp (25±15) were the most abundant Phytoplankton speciesin Station 1. For Station 2, the most abundant species observed were Melosira varians (25±19), whereas Melosira radiate was the most abundant species observed in Station 3 (35±29) and Station 4 (37±31). There was no significant difference (p>0.05) in the spatial variation of different species of Phytoplankton. For Zooplankton species, COPEPODA were the most abundant Zooplankton class with a percentage composition of 60.2% and 39.5% for wet and dry season respectively. PROTOZOA, CLADOCERA, and ROTIFERA had a percentage composition of 19.7%, 6.8%, and 10.3% for the wet season and 22.9%, 12.7%, and 11.9% for the dry season respectively. The least abundant class was CRUSTACEA with 0.2% in the wet season and INSECTA with 1.2% in the dry season. Centropages typicus (27±22) were the most abundant Zooplankton species in Station 1. For Station 2, the most abundant species observed were Anomalocera patersoni (10±6) whereas Eucyclops serrulatus were the most abundant species observed in Station 3 (27±24) and Station 4 (45±37). There was no significant difference (p>0.05) in the spatial variation of the different species of Zooplankton. The study showed that the discharge of abattoir wastes into Woji Creek resulted in an increase in the abundance of Phytoplankton especially those of algal origin which are pollution bio-indicators thereby causing eutrophication of the waterbody, the study also showed seasonal implications to the abundance of the plankton species.

Keywords : Phytoplankton, Zooplankton, Abattoir Wastes, and Creek.