Danube Salmon is Endangered because the species is severely fragmented within the Danube drainage, where most populations exclusively depend on stocking and natural reproduction is very limited due to habitat alterations and flow regime changes. The main current threat to the species is the flow regulation from hydropower dams which impact the species, and their prey's, habitat and pollution. Documented self-sustaining populations are very few. For example, these include the Drau, Mur, Melk, Pielach, and lower Gail rivers in Austria. Globally, they will have a combined area of occupancy of less than 500 km² (based on spawning areas).