Abstract

The physico-chemical parameters and plankton abundance of four artificial fish ponds in Omageyu Farms, Ijotun, Badagry, Nigeria was studied and analysed using standard methods monthly from June to December 2015. Water temperature, pH and dissolved oxygen ranged from 27.80 to 32.00°C, 6.90 to 7.40 and 6.80 to 10.00 mg/l, respectively in the four ponds. Water temperature, pH, and dissolved oxygen in Pond A were significantly different from Ponds B, C and D. Forty-five planktonic organisms, including 40 phytoplankton and 5 zooplankton species, were identified. Shannon Weiner index was highest for pond A = 2.824 and decreased in the order: pond C = 2.81, pond B = 2.797 and pond D = 2.767. Margalef’s index of species richness was greatest for pond D = 2.313 and least for pond A. Berger-Parker Dominance Index (BPDI) for the ponds decreased in order of ponds A = 0.2422, C = 0.2328, B = 0.192 and D = 0.1858. Total plankton in the four ponds showed positive correlation with dissolved oxygen. The class Chlorophyta was the prevalent group in the four ponds. The results showed that physico-chemical parameters have an influence on the distribution and diversity of plankton in earthen fish ponds.

Key words: Clarias gariepinus, earthen ponds, physicochemical parameters, phytoplankton, zooplankton.