Zooplankton (Cladocera) density and identification during seven successivelymonths in in Anzali wetland and compare with estuarine region and TheCaspian Sea

This research was done to assess the density of Cladocera an Anzali Swamp and Compare it with its density in estuarine regions and the Caspian Sea. Therefore, sampling was done during 7 months with 45-day interval from March, to September, 2011 at 5 stations including 3 stations in Anzali wetland, 1 station in estuary and 1 station in the Caspian Sea using 30-micron Planktonic nets. According to the achieved data, only 6 genera were found in this branch whose most density was at west swamp entry station with 41 numbers per liter. The maximum Cladocera density was seen during April with 22 numbers per liter. The results of such study showed that compared with three regions of Anzali Swamp, estuary and the Caspian Sea, the density of Cladocera was more in Anzali Swamp, then in estuary and it had the least density in the Caspian Sea. The statistical Analysis and one way variance results showed that the average Cladocera zooplanktonic density had a significant difference at various stations as well as different months. Also, there was a relation between physio- chemical factors and Cladocera density. Such relation was straight between pH and water temperature with Cladocera while it was inverted between transparencies and electrical conductive with their density.