Title: FEEDING EVALUATION OF MICROCRUSTACEA (CLADOCERA): RESPONSES TO VARIATIONS IN CELL VOLUME OF GREEN AND BLUE-GREEN ALGAE
Abstract: The grazing rate of three zooplankton species; Daphnia carinata, D. lumholtzi and Ceriodaphnia cf.quadrangula on six algal species at three concentrations are described in this paper.The effect of food density on ingestion rate was assessed by adding a suspension of algae to the tumblers and following the changes in concentration in the tumbler as the cladocerans consumed the suspension.Samples were taken and algal densities were measured every 15 minutes with a spectrophotometer.This study aimed to examine the role of cladoceran as grazers of algae under laboratory conditions.D. carinata removed algal cells at higher rates than the other two species when feeding in unialgal suspension.Quantitative differences in rate of food intake were found in suspensions of Ankistrodesmus falcatus, Scenedesmus obliquus, Chlorella vulgaris, Chlamydomonas reinhardtii, Anabaena circinalis and Microcystis flos-aquae.The small cells contributed by far the greatest fragment of green algae ingested by grazers.Filamentous A. circinalis and colonial M. flos-aquae can also be utilized by the grazers though the species was previously reported to have lethal toxic effects on cladocerans.Therefore, a management strategy using cladocerans for controlling undesirable cyanobacteria in aquatic ecosystem is contemplated to be necessary in the future.