Evaluation of fish farm effluent contamination using bio-indicators based on macroinvertebrate communities

Abstract

The progress of the aquaculture industry in Iran as an environmental and economical maintainable process needs an efficient and low-cost tool for regular checking of adjacent environments. Biological monitoring by macroinvertebrate is operative for assessment of water quality. Sampling operation was carried out to investigate the influence of aquaculture wastewater on macroinvertebrate communities at 4 stations over one year (spring, summer, autum and winter) in the Chehel Chai River. 2040 (19% spring, 18% summer, 25% autumn and 38% winter) macroinvertebrate specimens belonging to 6 orders and 14 families were recognized. The most abundance among the stations belonged to the Diptera and Chironomidae. Two groups of macroinvertebrate assemblages (sensitive to tolerance) and three groups of stations (upstream, outfall and down1 and down2) were identified with Heat map analysis. The study was showed that rainbow trout farm most often significantly increase in the influence of fine particulate organic material (FPOM %), NO3 and PO4. According to HFBI results, organic water pollution at different stations was classified as good (upstream), appropriate, relatively poor and poor (outfall). The combined results of the biomarkers were showed that the outfall station had more organic contamination than its predecessor station (relatively poor water quality) which required more efficient management based on the self-purification capacity of the Chehel Chai River.