Visiting the Vienna Zoo

4. 6. 2019

As a Research Assistant for the GoJelly project at the University of Southern Denmark, one of my tasks is to setup a continuous jellyfish culture for research purposes. In order to identify cultivation methods of small scales in aquariums to be able to up-scale it to the larger size for further jellyfish aquaculture, I went for a one week visit in Vienna Zoo.

Vienna Zoo or Schonbrunn Zoo is an amazing place to see many animals and learn about their life. It is also a place, with lots of experiences in breeding many different species of jellyfish.

The first morning of my visit, I was given a tour around the pavilion with aquariums and terrariums and their inhabitants. I was amazed how many species of fish, cephalopods, also the endangered ones, and jellyfish were being successfully reproduced here.

Because my focus was on jellyfish, I was shown and explained the whole process of cleaning the jellyfish exhibition tanks, feeding and water treatment. I cleaned my first jellyfish tank with Aurelia aurita, which is a jellyfish that does not cause a painful sting to humans. Its stinging cells, cnidocytes, do not penetrate our skin on the hands but still they are a powerful weapon to catch and kill the zooplankton.

To watch these beauties in their aquarium was very relaxing. Actually, to work in this environment was very relaxing. It was a lot of light physical work and the sound of water running and bubbling in the dozens of aquariums together with hundreds of the green water plants made the big aquarium room very soothing.

Taking care of jellyfish polyps stock required feeding every other day with subsequent water exchange. Vienna Zoo houses around 80 species of jellyfish polyps from all over the world and also exchanges them with different universities and marine centers. Only some of the polyps are strobilating at the same time and most of them serves as a stock.

After the polyps strobilate, they give a rise to ephyra – the next stage in the jellyfish lifecycle. Ephyra reminds me of a snowflake with its shape. It is an actively pulsing stage and already requires a source of a light water current in order to move around and catch the prey. The care is more intensive, feeding with zooplankton in the morning, water change about 5 hours later and feeding again, every day.

Once the ephyrae grow bigger, they are moved to bigger tanks where they bloom into their adulthood beauty.

During my week in Vienna Zoo, I got to see how much great care is given to every species of fish, cephalopod or jellyfish. I am very thankful for this learning experience and to my colleagues who always found the time for explanations. I truly enjoyed every moment of it. Thank you, Vienna.