Comparative Performance of the Indices Used for Bioassessment of Water Quality of Sangi Stream (West Anatolia, Turkey)

This study has been carried out to determine water quality of Sangi Stream (West Anatolia, Turkey) and to compare the performance of indices used. Five biotic and three diversity indices have been used for determination of water quality of Sangi Stream. The assessment of water quality has been done based on benthic macroinvertebrate and physicochemical parameters. The following biotic indices have been used: Saprobi Index (SI), Biological Monitoring Working Party (BMWP), Average Score per Taxon (ASPT), Family Biotic Index (FBI), Belgian Biotic Index (BBI), as well as the following diversity indices: Shannon-Weaver index (SWDI), Simpsons index (SDI), Margalef index (MDI) and Evenness (E1). Principal component analysis (PCA) has been applied to the physicochemical variables. The similarities between the sampling stations have been clustered by using Cluster analysis (CLUS). Our results have shown the presence of 9 taxonomic groups in Sangi Stream: Crustacea, Oligochaeta, Gastropoda, Ephemeroptera, Plecoptera, Trichoptera, Odonata, Coleoptera, and Diptera. The water quality along the Sangi Stream has varied from high class quality in station 1, 2, 3 and 4, to good and moderate quality in station 5 and 6. The results indicate that the SI, BMWP, FBI and ASPT were sufficient in the estimation of water quality in the examined watercourse. This study has clearly shown that a specific biotic index according to the ecological characteristics of Turkey should be developed.