Rotifera diversity indices: assessment of aquatic health of an ox-bow lake ecosystem in West bengal

A survey of the zooplankton communities of a water body was conducted from April 2013 to March 2014 in the Chhariganga oxbow lake in Block of Nakashipara of Nadia district, West Bengal, India and an analysis of rotifer group of zooplankton with using diversity indices like Shannon-weaver and Simpson diversity index, species richness and evenness, composition trends with total abundance was also carried out to assess the water quality and aquatic health of the oxbow lake ecosystem. Nine species of rotifer zooplanktons identified were Asplanchna sp, Notholca sp, Keratella sp, Anuraeopsis sp, Cephalodella sp, Monostyla sp, Platyias sp, Testudinella sp, Ascomorpha sp. Species Richness values of 5, 3, 4; Species Evenness of 0.96, 1.00, 0.96; Shannon-Weiner Index values of 1.55, 1.10, 1.33 and Simpson diversity index values of 0.22, 0.33 and 0.27 were found respectively during pre monsoon, monsoon and post monsoon in the oxbow lake. Total abundance of rotifer group showed density values of 280, 120, and 125 numbers per litre of water during those three seasons in a year. In the present study low diversity values of Shannon and Simpson diversity clearly stated that the selected lake is polluted and has high anthropogenic activity and this lake water is not suitable for aquaculture.