Benthic population of Jajrood River branches in Tehran province

In the present study macroinvertebrate community of Jajrood River branches was studied. Sampling from branches of Abnik, Zayegan, Lalan and Ahar was conducted in spring and summer of 1393. Benthic invertebrate were collected by Surber sampler (35 × 35 cm) and fixed in 10% formalin. Benthos samples were separated in the laboratory by lifting loop and were identified at genus level. To assess the ecological condition and water quality Hilsenhoff and EPT indices were used. In general, 28 genus and 3 phyla, 5 classes, 9 orders and 24 families were identified in macroinvertebrate community of these rivers. The highest density of benthos was seen in Lalan branch (842 per square meter), in spring and summer. Among the genera found in all branches, except in Ahaar branch, maximum density was seen for Epeorus genus in summer and Baetis genus in spring. Based on analysis of variance (ANOVA) and post hoc LSD test, significnat difference was only seen when benthos population of Ahaar was compared with the other branches (P <0.05).