Drought in Lower Austria: Fish stocks in tributary streams of the Große Erlauf being removed

Why the fish are in danger

The removal of fish is intended to relocate the surviving animals from the threatened sections of water into deeper, cooler and more oxygen-rich areas. This is meant to prevent the fish from perishing in the shallow, warming streams.

The Purgstall region lies in the Mostviertel in Lower Austria, where the Große Erlauf and its tributary streams form a sensitive ecosystem for cold-loving fish species. Trout, for example, require water temperatures significantly below 20 degrees Celsius and a high oxygen content in order to survive.

If water levels continue to drop, there is a risk that individual sections of the streams will dry out completely. In that case, the fish in the affected sections could no longer be saved, and the stocks could only regenerate over the course of years.

Effects on the entire ecosystem

The persistent drought is part of a longer heat phase that is prevailing across large parts of Austria. In other regions of the country as well, water levels of smaller rivers and streams are dropping, exacerbating the situation for aquatic life.

In addition to the fish, other water-dependent organisms are also affected. Falling water levels and rising temperatures alter the entire food web in the affected waters, as insect larvae, small crustaceans and aquatic plants likewise suffer under the conditions.

Emergency measure: removal of fish

Under fishing law, the removal of fish in such cases is an emergency measure coordinated by fishing rights holders and authorities. The caught fish are generally relocated to suitable sections of water where conditions for survival still exist.

In the long term, the drought poses a challenge for the management of domestic waters. Water cooperatives and municipalities must prepare for more frequently occurring low-water situations and develop measures to secure fish stocks.

The report from Purgstall carries the headline "Auch den Fischen ist es zu heiß" and thereby draws attention to the effects of the heat on domestic wildlife. The situation in the tributary streams of the Große Erlauf is considered an example of the consequences of climate change in the region.