The Sterlet was a widespread fish species in the Danube, which is currently only to be found in a few areas. The reasons are, in particular, the fragmentation of migration routes and the depletion of habitats in the Danube. With this project, further insights into habits and habitat requirements of the Sterlet are to be gained in order to subsequently be able to implement habitat improvement measures. For this purpose, the movements of sterlets presented in pre-projects in the Upper Austrian-Bavarian border section of the Danube are recorded and profiles of spawning habits are created in particular. Also, the data obtained so far will be further compressed in order to be able to subsequently make corresponding improvements for these species protected by the Habitats Directive. The national and international cooperation (river engineering, fishermen, nature conservation authorities, ...) in the biodiversity program is necessary and is also documented by regular meetings.