Ecology Research Unit, Department of Zoology Burdwan University, Burdwan – 713104, India.
The composition, abundance, frequency of occurrence and diversity of the net zooplankton species inhabiting Krishnasayer, a low flushing > 300 years old, shallow (8-10m depth), freshwater lake at Burdwan (23°16′N; 87°54′E), were investigated from weekly samples taken from 1m long × 1m wide × 1m depth surface water column (≤ 1m depth) over January-December 2005. Among net zooplankters collected, 4, 18, 4 and 5 species belonged to Protozoa, Rotifera, Copepoda and Cladocera, and 1 species belonged to each of the Decapoda, Branchiopoda and Ostracoda, respectively. The relative abundance was maximum (44.4%) for Rotifera and minimum (1.5%) for Decapoda. The species of frequent occurrence (100%) were Asplanchna brightwelli, Branchionus angularis, Filinia opoliensis, Keratella tropica, Tripleuchlanis plicata, Heliodiaptonius contortus, Eudiaptomous gracilis, and Daphnia lumlioltzi. Simpson's diversity indices demonstrated high scores (i.e., 0.925 0.961 for site I and 0.905–0.968 for site II), and these were maximum in July and minimum in November implicating that the limnological processes affecting net zooplankton species diversity operated almost equally throughout the surface water column of this lake, and across all seasons.
Net zooplankton, species composition, abundance pattern, diversity, freshwater lake, Krishnasayer
