Identification, Distribution and Abundance of Macroinvertebrates and Biomonitoring of the Ghale Rudkhan River, Guilan Province

Benthic macroinvertebrate-based indices are suitable tools for assessment of stream health and human impacts on its biological integrity. Since Ghale Rudkhan River is an attractive tourist destination and its surrounding population is growing, its water quality was examined usning biological indicators. Macroinvertebrate samples were taken monthly by a Surber sampler (mesh = 300 µ and area = 900 cm2) at five stations from May to December 2017. Samples were preserved in ethanol 96% and transported to laboratory for analysis. Total abundance, EPT index, EPT richness and percentage,EPT/CHIR ratios were determined. In total 5134 macroinvertebrates that belong to 35 genera, 30 families, 10 orders, 4 classes and 3 phyla were identified. The highest EPT richness was observed at the station no. 4 in May (607 ind.m-1) and the lowest was at the station no. 5 in October (7 ind.m-1). The presence of pollution sensitive species such as Epeorus sp. Rithrogena sp., Rhyacophila sp., Isopela sp., Gomphus sp., Cordulegaster sp., Coenagrion sp., Oligoneuriella sp., Heptagenia sp., Philorus sp. in Ghale Rudkhan River indicated the optimal quality of the river water.