Fig. 1
A location of the study site (red dot) in Germany. The Iller river (blue) is a right tributary of the Danube (orange). B Aerial map of the study site in Altusried overlayed with the simulated flow velocity at a discharge of 50 m3/s. White dots show HR2 receiver locations, red star marks the fishway entrance downstream of the hydropower plant, the yellow triangle marks where fish were caught, and the yellow plus-sign marks the release location. C Shows the bathymetry of the study site at a discharge of 50 m3/s. Water flows from south-east to north-west. Red dotted lines mark the borders of the area for which tag detections were analysed