Digital fish recording in Altenwörth

Lower Austria's longest fish pass, in Altenwörth, has been in operation since last year. Extreme periods of high and low water have recently restricted the tests. With the start of spring, the project team of LIFE Network Danube Plus hopes to finally demonstrate the success of the measure under water. 10,000 fish are being fitted with electronic chips for this purpose.

Ecology is manual work. Aquatic ecologists visit the fish trap in the side arm in Altenwörth on a daily basis. As the temperatures rise, more fish are found in the mobile fish trap every day. Every single specimen is measured, marked with a chip and recorded in a database. The chip is registered as it passes through the new fish passes on the Danube and recorded in an online database. This gives rise to precise data on the number of fish and their migratory movements.

The goal is to fit 10,000 fish with electronic chips. The migration stories of individual specimens are exciting. For example, some fish managed to make it as far as the lock of the Aschach power plant in Upper Austria – a migration of 200 kilometres!

New habitat on the Danube

Many fish appreciate the newly created habitat and remain right where they are in the new 12.5 kilometre-long side arm of the Danube. The water of the Krems-Kamp channel empties into the fish pass and ensures a continuous flow. A diverse riverscape arose during construction. The steep banks serve as breeding nests for the sand martins, while gravel breeders are found in the gravel banks.