There are over a hundred different species of jellyfish around Nice.
Depending on the winds, they are transported to the edge of the beaches but are present throughout the year now.
“We have the impression that they are mostly there in summer because there are more swimmers,” says Fabien Lombard, researcher at the Villefranche-sur-Mer Oceanographic Observatory.
The Pelagia, the best known to tourists because it stings, was normally present by period.
Since 1993, it has been there systematically.
In recent weeks, bathers on the Côte d'Azur have reported seeing a previously unknown jellyfish in Mediterranean waters.
"This Equorea, aequora forskalea by its Latin name, is not a new species," says Olivier Brunel, head of the aquarium service at the Oceanographic Museum of Monaco.
It is however surprising to observe it here knowing that it exists more in the Atlantic.
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The head of the aquarium explains: “In the six years that I have been in the region, this is the first time that I have seen them.
When you put your head under water, you notice them because there are twenty, sometimes a hundred in a line, carried in the current.
»To this exceptional fact, another which is no longer so at all: the presence of the most famous jellyfish for tourists, the Pelagia, very stinging unlike the Equorea.
Five years with jellyfish, five years without jellyfish
"We have the impression of being invaded every summer because that is when people go in the water," specifies Fabien Lombard, researcher at the oceanography laboratory of Villefranche-sur-Mer. .
As we don't really have reliable measurement tools, they are the ones that serve us for collecting information.
We can't really say if there are more, but in 2012, there were between 100 and 200 tonnes of jellyfish per km².
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Pelagia is therefore present throughout the year in the Mediterranean.
"Depending on the winds, it is transported to the edge of the beaches but if the next day there are reverse winds, we think there are no more", specifies Fabien Lombard, also a lecturer. at Sorbonne University.
“What should be noted, however, is that there is no longer a jellyfish year.
Since 1993, they are systematically there every year whereas before, it was by period.
We spent five or six years with jellyfish and then five or six years without jellyfish ”.
"A sign of deregulation"
With more than a hundred different species off our coasts, "this situation is not dramatic but it is the sign of a disturbance, that something is wrong", analyzes the head of department at the museum. of Monaco. “Human activity, which pollutes our environment and eliminates other fish that also feed on plankton, gives favorable conditions for jellyfish to develop. In addition, they no longer have predators like turtles so they continue to reproduce. "
For the two specialists, the ecosystem must be rebalanced. "The ocean has lived very well for 600 million years with jellyfish," says the researcher. But it has happened that a bloom of jellyfish sinks ships or stops the proper functioning of a nuclear power station near the sea. In the Mediterranean, it is the Pelagia that mainly annoys tourists. "
There are then netting systems installed during the summer season.
“An inefficient dressing” and “heavy maintenance” logistics for specialists.
The lecturer adds: “We must not seek to fight against proliferation by tapping on the symptom but we must act on the causes.
The environment has its own way of functioning, it is not a self-service system, it is not necessary to play with it.
The key is to take care of our planet ”.
To observe the Pelagia up close without getting stung, it is always possible to go to the Oceanographic Museum of Monaco, where there are some that are high.
"It is a perfect meditation support to raise awareness about what is happening in the sea and it is magnificent to watch", underlines the head of the aquarium service.
Planet
“Fried egg” jellyfish seen along the coast
Nice
A submarine to help researchers study jellyfish
Jellyfish
Nice
Monaco
Planet
Environment
Mediterranean