Investigation of Benthic Macroinvertebrate Besed on Bio-indicator in Zarin-Gol River, Golestran Provinc

Due to increasing population and demand for aquatic products and protein, in recent years the construction of fish farms, especially cold-water fish farms along the rivers has increased, and the effluent discharge of these farms without any treatment to the natural habitats of adverse and destructive effects. Eating the natural balance of the water will help the ecosystems. Among the most important communities of rivers and streams are large invertebrates. These organisms are able to represent water quality changes as a biological indicator. The purpose of this study was to investigate the effect of untreated effluent of fish farms on large invertebrates of Zarrin Ghee brook, because the inflow of these effluents into streams and rivers affects the structure and composition of streams, causing disruption of ecological balance.

In the present study large biodiversity of aquatic invertebrates as well as water quality using biomarkers in Zarrin River, Golestan province in winter 2015 and spring 1395 m2 at 4 stations and monthly (at entry, exit and 500 and 1000 m downstream farm) Fish breeding) was done by sampling with a Surface bumper level of 0.09 m 2 in three replications. Samples were fixed with 4% formalin and isolated, counted and counted in the laboratory.

Increased human activities, including the presence of fish farms in the area, can contaminate the surface water of the river. A total of 2179 specimens of large benthic invertebrates were identified, belonging to 35 genera, 28 families and 9 orders. Frequency of these organisms, were respectively Diptera with 46.9%, Ephemeroptera with 27.7%, Trichoptera with 16.9% and Lmbricida with 2.31% and the rest with 6.19%.

The result sowed that Shannon diversity, Evenness, TBI, IBI and IRWQISC were good indicators for water quality assessment in the study stations. In general, water quality in study area except station 2 (after fish farm) was desirable that the necessity of efficient water management to improve water quality in this region.