Macroinvertebrates as a BIO Indicator in Three Different Stream Sites of Bayugan Agusan del Sur Annielyn Tampus MSU-Iligan Institute of Technology, Philippines [email protected] Abstract - Macroinvertebrate communities are one of the most used groups in assessments of water quality, since they respond directly to the level of contamination of aquatic ecosystems. The main objective of this study was the assessment of three stream sites in Bayugan Agusan del Sur through biotic indices based on macroinvertebrate community. The sites have been tested using the kick seine and dip net method, which assessed on the month of June. Identification of individual taxa and their tolerance are based on Identification and Ecology of Freshwater Invertebrates by The Murray- Darling Research center Bug guide Water quality monitoring was computed with the use of Water Quality Index (WQI) calculator. A total of nine orders were recorded; Decapoda, Ephemeroptera, Hemiptera, Plecoptera, Coleoptera, Megaloptera, Trichoptera, Gastropoda, and Diptera, during the sampling time on June 2013. Calaitan and Maygatasan stream sites were within the range of healthy habitat due to the presence of four good water quality indicators (stonefly, mayfly, toe bitter and riffle beetle). Calaitan stream obtained a water quality index of 6.7 and Maygatasan stream with a water quality index of 6.25. Bayugan City is within the range of moderate pollution due to low water quality attributed to disturbance caused by human activities. Bayugan City obtained a water quality index of 4 and has the highest values of parameters such as temperature and the lowest value result of DO and pH were sensitive macroinvertebrates can’t survive due to less amount of oxygen in the area. Keywords - Aquatic Macroinvertebrates, Physico-Chemical Parameters, Water Quality Index Remark: The full paper may be found in www.inrit2014.com The Fourth International Congress on Interdisciplinary Research and Development, 30 - 31 May 2014, Thailand 12.1 .