Jellyfish: A spring frenzy - Aquarium La Rochelle

Every year, spring marks the comeback of jellyfish on the French coasts. Especially numerous this year, their presence raises a few questions. Why are they gone during the winter? Is this early comeback a sign that summer will be hotter than usual? Let’s see the explanations of Pierre, biologist at the Aquarium.

Why are they so many jellyfish?

” The arrival ” of jellyfish during Spring is determined by different factors. Some species like the « Aurelia » reproduce at this time of year. But climate conditions are the main factor ! From one year to another, there can be the same amount of individuals at sea; but these animals moving with the currents can be drown to the foreshore. The anticyclonic conditions of April 2017, with a quiet sea, have increased their presence on the French coasts. In addition, they move along with their food: plankton which follows currents. This abundancy doesn’t have any relation with the temperature of the summer!

Are Jellyfish of the French coast dangerous?

About ten species of jellyfish can be found on the English Channel, Atlantic and Mediterranean coast. Rhizostoma pulmo can be frequently seen: without tentacles, they are not very urticant. The Aurelia Aurita and northern sea nettle jellyfish can be more dangerous. To avoid any contact the easiest way is to stay away… In case of sting, to ease the pain, it is recommended to clean the wound with sea water or to cover it with sand. Foaming soap or shaving cream can also be used.