ISSN (Print): 2328-3777, ISSN (Online): 2328-3785, ISSN (CD-ROM): 2328-3793 American International Journal of Research in Formal, Applied & Natural Sciences AIJRFANS 13-308; © 2013, AIJRFANS All Rights Reserved Page 1 AIJRFANS is a refereed, indexed, peer-reviewed, multidisciplinary and open access journal published by International Association of Scientific Innovation and Research (IASIR), USA (An Association Unifying the Sciences, Engineering, and Applied Research) Available online at http://www.iasir.net Assessment of Daphnia, Moina and Cylops in Freshwater Ecosystems and the Evaluation of Mixed Culture in Laboratory Md. Faruque Miah, Somit Roy, Ekhtiar Jinnat and Zobada Kanak Khan Department of Genetic Engineering and Biotechnology, Shahjalal University of Science and Technology, Sylhet, Bangladesh. Abstract : This study was carried out to observe abundance and monthly variation of three zooplanktons in four different aquatic ecosystems of Sylhet during the period of March to June 2013. Cyclops, Daphnia and Moina was considered for this study and the abundance of these zooplanktons was recorded highest in April and lowest in March in all the experimental ecosystems. Among four water samples, planktonic abundance were recorded maximum in pond 1 (Daphnia 47.1%, Moina 26.1% and Cyclops 11.9%), followed by pond 2 (Daphnia 30.9%, Moina 20.1% and Cyclops 10.4%) and pond 3 (Daphnia26%, Moina 17.8% and Cyclops 8.5%) whereas minimum zooplankton was recorded in river water (Daphia 20.1%, Moina 14.9% and Cyclops 2.8%) respectively. The relationship of three zooplanktons with physico-chemical parameters (pH, temperature, CO 2 , COD, BOD, DO, Alkalinity, NO 2 -N, NO 3 -N) were also measured considering their monthly variation. During this study, mixed culture of these three zooplanktons (Daphnia, Moina and Cyclops) was practiced in the laboratory conditions. Culture was done at two aquariums using yeast extract for 21 days of experiment. Final abundance was recorded 1360±20 zooplankton/liter in aquarium1 and 1015±20 zooplankton/liter in aquarium 2, while initial recruitment of zooplanktons was 55/litre in both aquariums. This result suggests that zooplanktons culture in laboratory could be most potential for aquaculture. Key words: Zooplankton, pond, river, physico-chemical factors, culture I. Introduction Zooplanktons are the main sources of natural food for fish and shellfish which is directly related to the survival and growth and these are the base of food chains and food webs in all aquatic ecosystems. They also play a major role in recycling nutrients as well as cycling energy within their respective environments. Zooplanktons are an essential food item of omnivorous and planktivorous fishes [1] and the most essential for larvae culture [2]. The abundance of zooplankton in a water body is regarded as an indicator of productivity. Both the qualitative and quantitative abundance of zooplankton in a fish pond are of great importance in managing the successful aquaculture operations, as they vary from location to location and pond to pond within the same location even within similar ecological conditions [3]. In order to fisheries development and to increase the present production level, proper and scientific management is essential in which the knowledge of water quality and natural productivity plays an important role. Though huge number of zooplankton is available in freshwater and all of them are highly important in aquaculture, however, Moina, Cyclops and Daphnia are found in diverse natural environments especially in freshwater [4]. These three zooplanktons with higher protein contents are essential for fish larval growth as well as contain a broad spectrum of digestive enzymes such as proteinases, peptidases, amylases, lipases and even cellulase that can serve as exo-enzymes in the gut of the fish larvae. They are the finest and most universally accepted live foods for most fish. Different zooplanktons are being culturing both in laboratory as well as small environments for using in fish and shrimp larvae culture in several countries but no available practice of zooplankton culture in Bangladesh. Normally Artemia are being used in shrimp industries import from Europe and USA as dry cysts. Zooplankton culturing certainly has the potential to reduce the need of purchasing frozen or live fish feeds like brine shrimp, bloodworms, glassworms, Tubifex, or California blackworms as well as cost effective and time consuming for mass production.