Exceptional nesting season for Mediterranean loggerhead turtles

In July 2023, seven loggerhead turtle (Caretta caretta) hatchlings were counted on the French Mediterranean coast.

For several years now, the Observatoire des Tortues Marines (OTM) and the Réseau Tortues Marines de Méditerranée Française (RTMMF) have been observing an increase in turtle reproduction along the Mediterranean coast.

Between 2016 and 2022 along the French coast, four sea turtle clutches were observed between the Var and Hérault regions: Saint-Aygulf (2016), Villeneuve-lès-Maguelone (2018), Fréjus (2020) and Valras (2022).

2023 was particularly exceptional, with 7 clutches counted in July alone:

• One in Alpes-Maritimes (Villeneuve-Loubet - July 2) ;
• Two in Hérault (Marseillan - July 9 and Sète - July 17);
• Four in the Var (Porquerolles - July 15, Saint-Cyr-sur-Mer - July 16 and Hyères - July 23 and 27).

Thanks to the mobilization of numerous local players, including French Biodiversity Agency staff, Marine Protected Areas managers, RTMMF members and local authorities, these nests are now protected by enclosures, and awareness campaigns have been launched for beach users. If the embryos develop normally, it will be necessary to wait until the end of the incubation period (55 days on average) to hope to see the baby turtles (or wrigglers) head out to sea.

While these closely spaced events are excellent news for biodiversity, they remain very difficult to explain. Are sea turtles colonizing new nesting habitats? Is this the result of an increase in water temperature, a change in currents or the natural evolution of nesting habitats?

Scientists will need a few more years and a lot more data before they can answer these questions.