There were precisely sixty-three of them. Sixty-three small Loggerhead turtles hatched during the night of September 10 to 11 on the beach of Marseillan, in Hérault. A magical, touching moment, immortalized by the scientists who were feverishly awaiting this moment. The laying had been carried out between July 9 and 10, it was enough to wait about two months to witness their hatching, then the emergence of this cohort of twisters.
If it is so anticipated, it is because the moment is rare in mainland France: on average once a year. Well, normally. Because this year 2023 is extraordinary. In total, on the French Mediterranean coast, eleven clutches have been recorded. In Sète, a week later, 34 twists in turn joined the big blue. In much more complicated conditions with raging seas, in full weather alert (orange then red) and a much lower birth rate.
What impact does climate change have?
“The nesting of a loggerhead turtle remains an extremely rare event. But this year, it’s really exceptional,” underlines Céline Ferlat, marine turtle project manager at CestMed (Center for the Study and Conservation of Mediterranean Marine Turtles). And this is not specific to mainland France. In Spain, where the number of clutches is similar to that of France, 25 nests have been recorded. And Italy breaks all records with 416 clutches in mid-September. So, obviously, this explosion of births raises a lot of questions among specialists. And in particular that of the impact of climate change.
“We will need hindsight and several years before drawing conclusions on this phenomenon which is too recent. Today, we can only consider hypotheses, continues Céline Ferlat. Global warming is one of them, of course. The warming of the Mediterranean has been considerable this summer and may have resulted in a much more favorable environment for the loggerhead sea turtle to breed.” But this is not the only avenue considered. “Typical nesting sites may also have disappeared and explain why turtles lay eggs in unusual places.”
Umbrella species, essential for the environment
“Is this activity due to a change in currents or the natural evolution of nesting habitats? Protection efforts carried out for decades in Greece and Turkey [d’où proviennent majoritairement les tortues qui fréquentent nos côtes] do they play a role? », also asks the Marine Turtle Observatory.
Villeneuve-Loubet, Marseillan, Porquerolles, Sète, Saint-Cyr-sur-Mer, Fréjus Plage, Hyères, Pietracorbara and Ajaccio… The turtles laid eggs in eleven identified locations this summer. “There is no guarantee that this will lead to growth in the sea turtle population. We can only hope so, underlines Céline Ferlat. Witnessing so many clutches is in any case an encouraging sign. »
The seven species of sea turtles are all placed on the IUCN (International Union for Conservation of Nature) red list of endangered species. They are endangered by plastic, which they mistake for jellyfish, by the quality of water in the Mediterranean, and more generally by human activities. They are a witness to the quality of the environment, in addition to having a notable ecological role: “They are what we call an umbrella species,” concludes the CestMed specialist. Their action is essential for marine flora, particularly for seagrass beds, which are nurseries for fish. »