Distribution and Density of Zebra Mussels (Dreissena Polymorpha Pallas, 1771) and Related Some Environmental Properties in Euphrates River, Iraq

Abstract

The present study was carried on the Euphrates river /middle of Iraq, from October 2011 to September 2012 between Al-Musayyib city and Twereej City. Sampling were monthly from three sites in study area for studying some physical and chemical properties to river water ( air &water temperature , p H , EC , TDS ,TSS , Dissolved oxygen , transparency ,Total alkalinity , Total hardness, calcium , magnesium )  , also measured the concentration of chlorophell -a as indicator of biomass and primary productivity in Euphrates river. This study include collected the samples of zebra mussel from study sites to calculated the density and distribution of the species.The results showed the impact of spatial and temporal variation of environmental properties under study on the distribution and density of D.polymorpha .The species was recorded during most of time and sites of study and this species being invasive species  was recorded for the first time in this region. Fluctuation was observed in the total density of D.polymorpha and the highest values were recorded in the sites (3) ( 23.7 individual /m2) during March 2012 and absente during October 2011 and September 2012 . Statistical analysis was done using the canonical correspondence analysis (CCA).

Keywords: Zebra mussel; Biodiversity; Invasive species; Euphrates River; Iraq.