More than a year has passed since the opening of the Greifenstein fish bypass. In just 14 months, the ecologists were able to “mark” 10,000 fish using an implanted chip. So far, 46 out of 52 species of Danube fish have been identified. Particularly pleasing is the large stock of young specimens of the main fish, the “common nase”.
Fishing with landing net and scanner
A team of ecologists from the company “Profisch” battled along the 4.4 kilometre-long bypass channel at intervals of two weeks and recorded every fish. Some were previously marked specimens, others were new fish that were added to the database for the first time. The database reveals plenty of proof of success. About 15% of the fish stay in the accompanying stream for longer than a month. This shows that the fish bypass is becoming accepted as a habitat. The ecologists are especially pleased about the large stock of young and older “common nase”, the main fish in the project. Plenty of evidence of unusual species, such as the pearlfish (Rutilus meidingerii), was also found in the Danube.
Barrier-free and ecologically diverse
“The full accessibility of the power plants is merely the minimum standard of the EU’s Water Framework Directive. We have set ourselves the goal of exceeding this by creating new habitats along the Danube and connecting existing land restoration areas,” says project leader David Oberlerchner. Supporting this are the committed partners along the Danube: the provincial fishing associations and provincial governments of the federal provinces of Upper and Lower Austria, the Federal Ministry for Sustainability and Tourism, and above all the European Union within the scope of the LIFE project “Network LIFE project "Network Danube".
Nature is reclaiming the wetlands
It is also good to see how plant life is recovering along the fish bypass. The more protective this growth, the better it is for the habitat surrounding the fish bypass. A natural forest edge has a high ecological value – extensive clearing along the service road would set these efforts back years. The service road along the stream will therefore remain blocked off for safety reasons. So nature has more time to regenerate itself.