Nowadays, many indicators have been developed to assess water quality and ecological classification of rivers based on variations in ecological structure. The goals of the study were assessing the ecological status, the effects of human land use, and the performance of the most common ecological indices for fishes and macroinvertebrates as biologi cal evaluation of the Jajrood River.
In the present study, sampling of water, macroinvertebrates, and fishes was done at 10 stations in November 2015. The physical, chemical, and biological parameters including temperature, turbidity, velocity and depth of water, acidity, electrical conductivity, BOD5, nitrate, ammonium, phosphate, dissolved oxygen, and fecal coliform were measured onsite or after the sampling. Macroinvertebrates sampling was performed using a Surber sampler with three rep lications at each station and fishes were sampled using an electrofishing apparatus. Different physicochemical, macroinver tebrates, and fish indices were used to evaluate the integrity of the Jajrood River. The Canonical Correspondence Analysis )CCA) test was also used to analyze the relationship between macroinvertebrates and fishes with physical, chemical, and biological variables.
Overall, 481 specimens belonging to eight species of fishes and 2435 macroinvertebrates belong ing to 15 families were collected. Among all sampled fishes, Oxynoemacheilus bergianus and Paracobitis malapterura had the highest and lowest abundance, respectively. The highest total percentage of macroinvertebrates abundance belonged to
the Baetidae family of the order Ephemeroptera and the lowest percentage belonged to the Polycentropodidae of the order Trichoptera. The results of Canonical Correspondence Analysis )CCA) showed that the efficiency of the EPT/CHIR index for macroinvertebrates was better than others. The Karr Biotic Integrity )KBI) that was used for fishes as a water quality index was suitable for the river.
The present study was the first one that used both fishes and macroinvertebrates indices with physicochemical parameters for ecological integrity assessment. From the findings of this study, it can be concluded that the urban-rural and agriculture wastewaters and the Latyan dam had the most negative impact on the ecological structure of the river.