Some observations of Zooplankton composition and abundance in river Damodar during winter season. Running Title:- Some observations of Zooplankton composition and abundance.

Abstract

ABSTRACT

The investigation has been made to examine the hydrological condition of the studied area (some physicochemical parameter of water, zooplankton community and its diversity).

During the study it was observed that the trend of variation of water temperature was from 15.9ºc to17.5ºc. pH was found to alkaline ranging from 8.5 to 9.1. During the study there was a fluctuation in O₂ level from 3.2 mg/lit. to 5.2 mg/lit. Free CO₂ was found to be higher throughout the study with a variation from 14 to 18 mg/lit.

In the study of Zooplankton, Cladocera and Rotifera were chiefly present comprising mostly of Daphnia sp, Rotaria sp., Brachionus sp. and Cyclops spp. Besides theae groups of species  Copepoda was also present.

A total of 10 genera including one larval form were found during study. Among 10 genera only 5 were dominant ( Daphnia sp., Rotaria sp., Brachionus sp., Mesocyclops sp. and nauplius larvae), within these dominant species the most dominant were Daphnia sp., Rotaria sp. and Brachionus sp. which occur more than three times during study.

While the community study was concerned it was found that the species richness ranged from 0.734 to 1.17, Evenness from 0.911 to 0.975 and Shannon-Wiener index value was varied between 1.85 and 2.43. The mean values of them were 0.924, 0.939 and 2.25 respectively.