S.R. Regi and V. Reshmi
Abstract
The diversity of zooplankton in Veli-Akkulam Lake, Kerala, was evaluated over the period from October 2008 to September 2010. The zooplankton community of the lake comprised of 19 species, including copepod nauplii and fish eggs and larvae, categorized into seven groups â Protozoa, Rotifera, Cladocera, Copepoda, Ostracoda, Insecta and Fishes. The most dominant group was Rotifera with seven species, followed by Copepoda having four members. Although species distribution was found to be almost even throughout the lake, highly significant variations in the monthly abundance of different zooplankton groups were observed between the six study locations during both the years of the study. The prevalence of rotifers, particularly Brachionus sp., indicates the eutrophic characteristics of the water body and the significant amounts of organic matter it contains. The significant consistent decrease in zooplankton abundance from the Veli to the Akkulam regions of the lake, along with a marked reduction in copepod diversity compared to previous studies, clearly reflects the declining ecological health of the lake.