Effect of Physico-chemical Factors and Plankton Abundance in Selected Tropical Fish Earthen Ponds' Water

The study investigated the plankton diversity and abundance of three selected on-farm research fish ponds in Nigerian Institute for Oceanography and Marine Research, Lagos. Samples were taken from three ponds using standard procedure and physico- chemical features of the water bodies were measured. Plankton of class (Bacillariophyceae, Chlorophyceae, Cyanophyceae and EuglenophyceaeI) and Zooplanktons of (Cladocera, Rotifera and Copepoda) family were found. There were varying results for the phytoplaktons and zooplaktons respectively during the study. The highest percentage composition for phytoplankton was recorded in Pond 1 (94.11%), and the highest Shannon-Weaner diversity (1.265%) in pond 2. The highest percentage of zooplankton was recorded in pond 2 (91.67%). Utilizing the parameter of Shannon index value, the abundance value for zooplaktons was not remarkable. Statistical association between parameters and abundance reflected that abundance was positively correlated with temperature, and negatively correlated with pH while the levels of dissolved oxygen (DO) were positively correlated. The low densities and plankton diversity in pond 3 was an indication of low pH and high transparency as a result of nutrient depletion.Keywords: Abundance; physico-chemical factors; phytoplankton; zooplankton; fish pond