A diagonal brush fish pass was installed at İncirli weir which is located in the Eastern Black Sea in Turkey in İyidere river basin. In İyidere River basin a considerable reductions in fish population have been observed due to Hydro Power development in last ten years. We investigated the attraction and passage efficiency of brush fish pass by using PIT tagging method. Fort this purpose we installed two antennas at the entrance and exit of fish pass. Elevation difference between antennas is 4 meters. This mountain stream is rich with fish biodiversity which have 13 fish species. The target fish species in this Project is Salmo coruhensis. For the following fish species in th region we calculated the passage efficiency as follows; For trout (Salmo coruhensis) 83,33%, for spirlin (Alburnoides bipunctatus) 57,58%, for Barbel (Barbus taurucus) 61,54%, for european chub (Squalius cephalus) 87,50%, for banarescu’s barb (Capoeta banarescui) 100% and Iyidere goby (Ponticola rizeensis) 50%. Moreover we obtained fish ascending times for different fish species. The body lenght of the fish varied between in the range of 90-270 mm. The main advantages of brush fish pass appears to be it provides passage for small-bodied fish (L<150 mm). The ascending time of fish varied between 20 minutes to 2.2days.
Key words: fish passage, efficiency, Iyidere stream, Turkey