The project LIFE Sterlet aims to strengthen the wild populations of the sterlet (Acipenser ruthenus) in different sections of the Upper Danube River. Since its start in 2016 more than 202.000 sterlets in three designated areas have been released until 2020. Eggs and juveniles are incubated and reared in a streamside hatchery container with untreated Danube water and natural food.
In spring 2020 30 hatchery reared and 10 wild individuals were equipped with hydroacoustic tags to follow their migration and document their habitat use with fixed hydrophones and active tracking in the 100km long stretch between the hydropowerplant Freudenau in Austria and the hydropowerplant Gabcikovo in Slovakia. First analysis of the data revealed significant differences in the daily and seasonal migration patterns of single individuals, with some animals being rather stationary and others covering the whole distance downstream and half the distance back upstream in just three days.