Seasonal Variations in Species Composition and Community Structure of Zooplankton in a Two Perennial Lakes of Coimbatore, Tamil Nadu, Southern India

The present investigation was carried out in selected lakes of Coimbatore: Sulur and Ukkadam, Tamil Nadu, Southern India.The seasonal variations of zooplankton species composition and diversity were studied for a period of two years from March-2012 -February-2014, on monthly interval basis of four seasons like summer, pre-monsoon, monsoon and post-monsoon.Totally 34 species of zooplankton, which include 11 species of Rotifera, 10 species of Cladocera, 7 species of Copepoda and 6 species of Ostracoda were recorded and identified from Sulur lake and 28 species of zooplankton comprising 10 species of Rotifera, 8 Cladocera, 6 Copepoda and 4 Ostracoda were recorded in Ukkadam lake.The Rotifera was found to be predominant with 34% followed by crustacean zooplankton of Cladocera (31%), Copepoda (25%) and Ostracoda (10%) at Sulur lake while in Ukkadam lake for Rotifera were found to be predominant with 35% followed by Cladocera (30%), Copepoda (27%) and Ostracoda (8%).The population density of zooplankton recorded at Sulur lake was ranged between 51,895 and 1,07,505 ind./L and in Ukkadam lake it was 89,385 and 1,89,435 ind./L.Zooplankton population was found to be higher in summer months (March to May-2013) while lower in monsoon months (September to November-2012) and intermediate numbers were recorded during post-monsoon season in the Sulur and Ukkadam lakes.The present result revealed that the zooplankton productivity was high.Therefore, it could be continuously utilized for the inland aquaculture purposes if properly water quality management measures are adopted in the lakes ecosystem.Hence at regular intervals monitoring of water quality, proper maintenance and lake management measures should be adopted by public and governmental organizations to sustain these ecosystems for future generations.