Description of sampling sites along the Upper Tisa

The research was done on the upper section of River Tisa from its two sources (rivers Bila Tisa and Chorna Tisa) in the territory of Carpathian Ukraine down to the confluence with River Szamos in Hungary (Fig. l: map). The research was carried out between 1-22 August 1995 within a single expedition. Considering the influence of the tributaries of River Tisa on its water-quality, we extended our research onto the rivers Tereblia, Teresva and Batar. The biological samples were collected at 16 sampling stations. A thorough description of these stations is given below, as we consider it to be important to interpret the presence or absence of certain species