Hellabrunn Zoo releases hatchery-bred river trout into Auer Mühlbach

The Fish Hatchery at Hellabrunn Zoo runs an in-situ species conservation project, which promotes the protection of the regionally endangered river trout. 

Today, in the sunshine and under a white-blue sky, about 150-200 juvenile fish were placed in the Auer Mühlbach river in cooperation with the Isarfischern e.V (Isar Fishing Association). Located in the Mühlendorf village at the zoo, the hatchery invites visitors of all ages to experience the endangered native species up close and learn more about them. Many visitors are surprised to discover that in addition to native birds and mammals, several species of fish are also regionally endangered in Bavaria. River development and transverse structures in rivers, streams and lakes are responsible for the continuous decline in many stocks. The introduction of the juvenile fish is therefore an important nature conservation measure in which Hellabrunn Zoo is actively involved.

Species conservation in the Fish Hatchery

In the last few weeks, the zoo has successfully bred around 200 river trout in the Fish Hatchery. These have now been placed in the Auer Mühlbach river in cooperation with the Isar fishermen, who have the right to stock the waters flowing through the zoo. The released fish are intended to help stabilise stocks and strengthen local biological diversity.

"Since its opening in 2018, the Fish Hatchery in the Mühlendorf has housed an important in-situ species conservation project – a conservation project in the natural habitat of the fish species. Endangered species are successfully bred here and resettled in native waters. This species conservation project is another example of how Hellabrunn Zoo is making an important contribution to preserving local biodiversity,” says zoo director Rasem Baban.

The river trout nursery

The hatchlings are cared for in so-called nursery troughs. Fresh, oxygen-rich water is constantly supplied. As a result, the animals floating in the water receive an even, optimal supply of oxygen. “Breeding native river trout is quite challenging. They are extremely sensitive to the temperature and oxygen content of the water,” say Lena Bockreiss, curator at Hellabrunn Zoo. It takes about 40 days for the young fish to hatch. “The river trout bred at Hellabrunn are now around 10 to 25 cm long and strong enough to take care of themselves. They are being released into the Auer Mühlbach so that they can explore their habitat unhindered."