The experts use state-of-the-art technology, for example underwater ultrasound measurement. In principle, this is no different to what is standard for every gynecologist. Instead of cute babies, they look for fish underwater. Depending on where they prefer to swim, the final entry point into the fish migration aid is defined. This is also based on the modern approach of not only opening up a path with a fish migration aid, but also expanding the fish's living and spawning space.
This involves the use of a tried-and-tested device that has not been used for a long time, a so-called "diving barge". A long time ago, this was a kind of underwater lift that was used to guide a diver from a boat to his deployment sites below a power plant. Instead of a diver, a modern ultrasound camera is now installed.
Manuel Langkau and Marc Zeyer from LFV Hydroakustik (http://www.lfv-hydroakustik.de/) are specialists in sonication for fish. They have installed their monitoring technology on the diving platform. The vehicle is towed by the tried-and-tested VERBUND icebreaker "Röthelstein", which is used for cargo trips along the entire Danube in summer.
