Macroinvertebrate study of Caspian Sea river estuaries in Guilan province

Macrobenthos were performed the main group of the Caspian Sea funa while they have not completely attentived espacilly in estuaries environoments. In this survey were studied eghiteen river estuaries in Guilan province off Caspian Sea southwest. The macroinvertebrate sampling was conductedseasonally at egith station during winter 2009 to summer 2009. The macrobenthos organisms were sorted and identified as possible level in genus or species. The results presented fifteen orders including thirty six families. The most presentation of genus belongs to Chironomidae family with twenty six genus while others were included forthy three genus. The Stenogammarus genus had the normally distribution between seasons while the most abundance was linked to Eukifferiella and Cricotopus during winter and spring 2009 nearly same as Streblospio and Limnodrilus. The Cerastoderma was showed a high percentage with decresing of others especially during summer 2009. In this paper have been described the fluctuation of benthic aboundance according to biological characteristic and the environoment degradation.