New jellyfish discovered in the Wadden Sea

Published: 31 March 2014

Researcher Lodewijk van Walraven recently discovered a new type of jellyfish in the Wadden Sea. It is a medusa jellyfish measuring just 15 mm. Lodewijk made the discovery as part of his doctorate research for Deltares and the Netherlands Institute for Marine Research, which he completed in 2015. His work represents a major step forward in our understanding of the role played by jellyfish and it will contribute to the more sustainable management of the North Sea and Wadden Sea.

Knowledge about jellyfish in Dutch seas still patchy

Deltares and the NIOZ are researching jellyfish near the Dutch coast because our knowledge about species, populations and life cycles is still very limited. And we still have only a poor understanding of why jellyfish come and go so quickly.

More dominant role of jellyfish causes major damage worldwide

We urgently need to find out more about jellyfish because there is a suspicion that developments in the North Sea and Wadden Sea are following the same pattern as the North Atlantic Ocean, the Baltic, the Mediterranean Sea and the Black Sea, where the numbers and species of jellyfish are changing. That has a major effect on not only the ecosystem but also on tourism, fishing, and energy and desalinisation companies. Jellyfish are playing an increasingly dominant role in other seas as well, causing considerable damage to both the environment and the economy.

Link between jellyfish population and quality of the sea

Leading international scientists think the success of the jellyfish is linked to the presence of fertilisers, climate change, over-fishing and the increase in marine infrastructure. The increasing dominance of jellyfish would seem to be a good indicator of the quality of the sea.

Het nieuwe meduse-kwalletje is slechts 15 mm groot.

The new medusa jellyfish measures just 55mm