You may have noticed it, or worse yet, you have encountered it near you when you went swimming, jellyfish are more and more present on the literal edge. It is no longer rare to go to the beach in the Mediterranean and come across schools of jellyfish. This annual phenomenon causes distress to tourists and local populations, especially in summer when these animals appear in greater numbers on the Mediterranean coast at this time of year. But then why has there been a proliferation of jellyfish in recent years?
Jellyfish in the Mediterranean
There are several species of jellyfish in the Mediterranean, so there are around twenty species. They are mostly harmless to humans. There is, however, a stinging species present in large numbers, the pelagia noctiluca jellyfish, a purple jellyfish whose venom causes itching and burning. The jellyfish sting is then unpleasant and can burn you but if you respect the rules to follow in the event of a sting then the sting is in the vast majority of cases without consequences.
Jellyfish swim?
Jellyfish are often confused with fish. But the latter are not fish but actually belong to the plankton family. They have no fins and are made up of 98% water and therefore float by moving up and down in place, so they do not swim but let themselves be carried by the current.
Is global warming to blame?
In summer, the temperature increases, it rains less and the wind blowing towards the east, they naturally carry towards the edge of our beaches. It is a natural phenomenon, even if it is however reinforced by man. Where we can explain by global warming why they proliferate, it is quite simply because their predators disappear.
Indeed, the number one predator of jellyfish in the Mediterranean is the sunfish. But the latter is happening less and less because of its overfishing as well as the others. When a species has fewer predators, it will logically proliferate more and this is what happens with jellyfish. Their predators disappearing due to fishing.
Another proliferation problem linked to climatic causes is the appearance of jellyfish in the Mediterranean which are not normally present. Thus a giant jellyfish which can cause hospitalizations for humans arrived recently. The latter proliferates and begins to settle permanently, even if it is more present on the eastern side where the sea is warmer for the moment. It is therefore a much more problematic problem than pelagia noctiluca.
*Updated 22 July 2024
