Identification and community structure of macro-benthose in Gahar Lake (Lorestan Province)

Lake Gahar is located in southwest of Iran, in East Lorestan province and at 2350m above sea level. There is little information and few studies on limnology of this lake . This tectonic lake is known to have a unique macro- invertebrate fauna. In order to perform a complete research on the zoo-benthic community of the lake, the present study was conducted during a period of seven months from April 2011 to December 2011 with the exception of 5 months during very cold seasons when the lake was covered by ice. The benthic assemblage was sampled monthly from 3 sites in profundal zone. In total 6 genera and species and 5 families were found from which 1 species is unique in Iran. In this research, the dominant species of the lake are Quistadrilus multisetasus , Stylodrilus herngianusof class Oligochaets and Pisidium casertanum of class Bivalvia. Their abundance percentage determined in respect of total distribution were %69, %13 and %6, respectively. The maximum abundance of total population of macro- benthos in Gahar lake was 11617.78±4910.379 individual per square meter in May and the minimum was 1436.32±671/87 individual per square meter in April.