Cormorant as a problem

Special project to bring fish back into the Enns

The first young fish have already been released into the Enns.(Bild: NP Gesäuse)

Construction by hydropower plants and predators such as cormorants and otters have drastically reduced the fish population in the River Enns. Now there is hope: grayling and trout are to be reintroduced to the Styrian waters with the help of a new special project.

Anglers have not been seen in the Enns for years. "We haven't caught anything for a long time, there are hardly any fish," says Adi Buder from the Gesäuse-Gstatterboden fishing association.

The fish population in the Enns collapsed at the end of the 1990s and has not recovered since.

Alexander Maringer, Nationalpark Gesäuse

For a long time, the 25 or so members could only watch as the stocks gradually declined: "Interfering with the natural course of the river by building structures is one thing. The other is the cormorant and the otter. All of this together has led to the biodiversity in the Enns being reduced to zero," explains the experienced conservationist.

The fish eggs were acclimatized to their environment in specially built containers.(Bild: NP Gesäuse)

This makes it all the more gratifying and relieving that an innovative project called "Homing" is apparently working: "Instead of relying on larger stocked fish for reintroduction, as is usually the case, we used fertilized fish eggs. These were placed in the Enns - protected in a box," reports Buder.

Better chances of survival
Immediately after hatching, the young fish were recently released into the wild. The great advantage of this concept: "The animals are familiar with the conditions of their home waters right from the start, which significantly increases their chances of survival," says Alexander Maringer from Gesäuse National Park, who is also supporting the project.

The hatched young fish.(Bild: NP Gesäuse/Picasa)

Specifically, the aim is to reintroduce the Danube brown trout and the Enns grayling to the Enns - and also to the Johnsbach - in the long term. Both species were once native here.

"We will carry out an initial survey of the fish population in three years' time. Perhaps we'll be able to see the first signs of success by then," says Maringer confidently.