The influence of humans on the environment is particularly strong in aquatic ecosystems. River regulations and channelization, built for the protection of human settlements and agricultural land, caused a big loss in size and dynamics of riverine habitats in the past. The construction of weirs and/or hydroelectric power plants resulted in a strong fragmentation of these habitats. Especially the Danube salmon (Hucho hucho, L.) as a top predator is very sensitive. This species dependent in all age stages on an intact environment and thus greatly affected by the degradation of aquatic habitats. This is evident in the steadily declining stocks in Austrian rivers, particuarly in the last decades. This thesis describes the present distribution of the Danube salmon in Austria, mainly based on documented catches by electro-fishing. The data is managed in an MS Access-Database, while the visual representation and analysis is done in ESRIs geographic information system ArcGIS 9.3. It is shown that the current distribution area (approx.1,300 km) is less than half compared to the historical one (approx. 2,700 km). Confirmed natural reproduction can only be ascertained for about 485 km of the Austrian river system. This length corresponds to less than 20% of the historical distribution. Data analysis shows a significant correlation between the conservation status of population of Danube salmon and the length of continuous water bodies. Additionally, a negative impact due to hydromorphological pressures, especially due to impoundments and hydro-peaking power plants is detected.