By Rayane Chbouki
An attractive summer destination, the coastlines attract millions of tourists from all corners of the world to enjoy the sunny climate. Nevertheless, we’re currently witnessing a phenomenon that is growing year by year, and that is threatening this kind of tourism: the upsurge of jellyfishes on the beach lines. Natural life cycles or consequence of climate change… what are the reasons behind this worrying abundance?
Jellyfishes have always occupied the seas, especially the Pelagia noctiluca, characterized by her purple color. For instance, the Mediterranean Sea, whose waters are warming at a faster pace than other sea and oceans, offers a suitable environment for the proliferation of jellyfishes because higher the water temperature is, lower the age at which jellyfishes become sexually mature and so reproduce better (6 to 8 months instead of a year).
Figure 1. The Pelagia Noctiluca
Climate change and rising temperatures have accelerated this phenomenon. Moreover, human beings tend to intervene as well because overfishing and pollution are also factors to be taken into consideration. Indeed, overfishing upsets the maritime ecosystem because jellyfishes are not only gonna face less potential predators (like tuna) but also have more prey, therefore more food available.
In addition, the multitude of plastic bags hinders sea turtles, important predators of the jellyfishes, some releases of chemical products and agricultural fertilizers encourage the plankton bloom, organisms liked by these invertebrates. However, that doesn’t explain the high presence of jellyfishes on the coastlines.
In the case, the winds are to blame. This is because they’re the reasons behind various maritime currents meandering towards the coasts, or the jellyfishes floating according to the maritime currents are then urged towards these coastlines. Nevertheless, controlling the jellyfish population is an important step we must take.