Assessment of distribution and abundance of zooplankton communities in the Atrak River, Northern Khorasan Province
Subject Areas : New Technologies in Aquaculture Development
Keywords: Zooplankton, Diversity indices, Keywords: Atrak River,
Abstract :
Abstract Investigation of abundance and distribution of biological assemblages and compared them with similar ecosystems could provide precise information on the extent of contamination. Due to entry of industrial, urban and agricultural wastewaters to the Atrak River, study of biological biomass especially zooplanktons as a part of food web to be very important. This study conducted monthly in one year period between 2007-2008 in 10 stations. Sampling were done by filtration of 100 liter water by net (50µ mesh size) and fixed in formalin 4% and transferred to the laboratory for identification. In this study, three phylum include Ciliophora, Arthropoda and Rotifera indemnified that abundance of them were 20.09, 12.61 and 7.36 individual number per liter, respectively. Among these three phylum 8 genera identified including Chilodonella, Colpoda, Vorticella, Daphnia, Cyclops, Asplanchna, Ascomorpha and Brachionus. Chilodonella and Ascomorpha with 7.86 and 2.4 number/lit had the highest and lowest in number. The maximum and minimum Shannon and Simpson Biodiversity Indices were for spring and winter seasons. Also the trend in monthly changing of water temperature show that in March and October population was the highest and in winter with the decrease in water temperature and drop of food availability the zooplankton population decreases dramatically. In general, results indicate that the Atrak River is poor in diversity and frequency of zooplankton population.
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