Identification and distribution of benthic macroinvertebrates of Azarood River in western Mazandaran province, Iran

Macrobenthos play a very important role in aquatic ecosystems and are very effective in increasing biological production and also water self-purification. These invertebrates also are quality elements required for the classification of the biological status of the water bodies.One of the major scientific issues in the aquatic ecosystem is the river biological study. Accordingly, the purpose of this research is to identify macrobenthos fauna of Azarood River in Tonekabon city, as well as to investigate the effect of season and station type on their abundance. Sampling at 4 stations was carried out on the route of the Azarood River by Surber sampler from October 2011 to September 2012, monthly, with three replications. Simultaneously, water temperature and pH were measured.After isolating the specimens in the laboratory and fixing them in 70% alcohol, using valid identification keys, the specimens were identified at the level of the order, family, and some on the level of genus. The effects of season and station on frequency were analyzed by one way ANOVA. Of 1760 collected samples, 6 orders, 17 families, and 13 genera were identified as below: Of the order Diptera, 6 families and 3 genera, Ephemeroptera, 5 families and 4 genera, Plecoptera, two families and one genus, Trichoptera, two families and one genus, Pulmonata, one family and one genus; From Lepidoptera, one family and one genus were identified. Among the families, the Leptophilobidae family was the most frequent and the least frequent was the Valvatidae family. The highest density and the highest diversity of macrobenthos were observed at station 1 and in August. The lowest density and the lowest diversity were observed at station 4 in November. In this regard, it can be said that in spring and summer, due to increased vital activities such as feeding and reproduction, the abundance and distribution of Macrobenthos will increase. Station 1 was the most diversified due to its locations in the source, the low amount of pollutants and the high vegetation, and the station 4 was the least diversified due to the arrival of wastewater and high pollution.

Keywords:

Taxonomic , Macrobenthos , Azarood river , Mazandaran