Combination and abundance of Macrobenthic fauna invertebrates in the lower part of the Gorganroud River-Golestan province

This study was conducted to investigate abundance and species distributn of macrobenthos in 3 stations in Gorganroad River (S1:36 58 42E, 54 00 28; S2: 36 58 41, 54 01 27; S3:36 59 14, 54 02 54) from March to February 2013. Samples collected using Van ven grab in 3 replicates in each station. In the study area, 6 orders belonging to 9 families were indentified including Naididae, Gammaridae, Cardidae, Nereidae, Neritidae, Ampharetidae, Pyrgulidae, Ostracoda, Foraminifera, Balanidae and Cumaceae. The most abundant taxa were Ampharetidae (28.62%), Lumbriculidae (24.24%), Naididae (11.3%), Chironomidae (10.44%), Balanidae (10.39%), Gammaridae (6.14%), Nereididae (31.91%), Cardiidae (2.73%) and Tubificidae (2.19%). Generally, in all 3 stations the highest and  lowest biomass belonged to the Ampharetidae family (25410) and Tubificidae (1946), respectively.