The effect of Salmonidae farms on the changes of the macrobenthos society of the Haraz River (Gazanak to Niyak regions of Iran)

The present study aims to investigate large communities of macrobenthic inoculants to evaluate the impact of contaminants on the biological conditions of Haraz River ecosystem. For this purpose, two Niyak and Gazanak stations were studied during October to December. The frequency of benthos samples from Baetis sp. (40.31%), Caenis sp. (17.37%), Scopura sp. (9.04%), Hydropcyche sp. (16.03%), Chironominae sp.(13.80%) and Tubifex sp. (3.45%) were counted. In order to investigate the relationships between quantitative traits, Pearson correlation coefficient analysis was performed using SAS software version 4.9 and mean comparison using Duncan's multiple range Test. Error level for all attributes was considered 0.05. Results show an increase in the relative pollution of station 1 (Niyak) towards station 6 (Gazanak). On this basis, the highest and lowest rate of pollution was observed at G2 and N1 stations, respectively. Based on the Pearson correlation coefficient, benthos of the Choronomidae and Tubifex family, which indicate water pollution, showed direct relationship with all water qualitative factors, such as BOD, COD, DO, EC, Temp, pH, nitrate, phosphate, carbonate, ammonium, TDS and chlorine, except DO. While, other benthoses that are usually indicators of fresh water, are related to all factors, except DO. Therefore, the macrobenthic pollution of the Haraz River in the studied area, does not have environmental concerns.