Invasive comb jellies in Danish waters

6. 9. 2019

On 21st of August the GoJelly team members from the University of Southern Denmark went on a one-day cruise in order to harvest jellyfish and get to know the ecosystem in eutrophicated Limfjord area. It is a transitional fjord system with main inflow from the North Sea in the west and main outflow to the Kattegat in the east.

The SDU Go Jelly team got on board of Danish coast guard vessel, with very joyful crew that made us feel very welcome. The day started with a nice sunny weather but it soon changed into a bit of rain and clouds with a lot of wind. We harvested at three different stations within the Limfjord, using a ring net. At each of the stations, we also measured salinity and temperature of the water. Interestingly enough, we caught only 3 individuals of Aurelia aurita and none of Cyeanea sp. However, we harvested around 10kg of comb jellies, Mnemiopsys leidyi. The fact that we harvested almost exclusively the comb jellies can mean that they are highly competitive with the Scyphozoa jellyfish in this area.