Are they dangerous?

Jellyfish are on the loose in Vienna: are they dangerous?

Jellyfish can now also be observed in the Danube.(Bild: Jennifer Huber-Stern)

Huge swarms of jellyfish are currently on the move on the New Danube in Vienna. What is this curious natural spectacle all about and are the creatures even dangerous?

On Thursday afternoon, many swimmers were astonished by the white carpet that suddenly appeared on the New Danube relief channel not far from Weir 1. The jellyfish are on the loose in Vienna!

"Everything was full of the animals. It looked like it was snowing underwater," says Krone reader Jennifer Huber-Stern, who was also surprised.

"It looked like it was snowing underwater," says the Krone reader, who photographed the jellyfish for us.(Bild: Jennifer Huber-Stern)

Indication of the good water quality of the Danube
The current high water temperature is primarily responsible for the emergence of the exotic animals. It must be more than 25 degrees Celsius. The New Danube is currently a warm 27 degrees, and the Old Danube is even 28 degrees.

I almost took a jellyfish ashore on my head after surfacing!

„Krone“-Leserin Jennifer Huber-Stern

This is a good sign for the city of Vienna. The presence of the animals is a natural indicator of good water quality, as they are particularly sensitive to environmental influences and can only develop in clean waters, according to the Vienna Water Department (MA 45).

Known occurrences in Vienna to date: Old Danube, New Danube, Kuchelau harbor on the Danube and various floodplain waters.

The animals are widespread as sessile polyps in clean floodplain waters, ...(Bild: Jennifer Huber-Stern)

... the development into free-swimming jellyfish is relatively rare ...(Bild: Jennifer Huber-Stern)

... at water temperatures above about 25 degrees.(Bild: Jennifer Huber-Stern)

At the same time, the all-clear is given. There is no cause for concern, as the little creatures are completely harmless to humans. Although the freshwater jellyfish have stinging capsules, these cannot penetrate human skin.

The phenomenon usually only occurs once a year. So if you want to see this unique natural spectacle, you should hurry!