- Loggerhead turtles in the Mediterranean are expanding their nesting range westward to the coastlines between Italy and Spain.
- Researchers say rising sea temperatures due to global warming are accelerating juvenile loggerhead growth in the foraging grounds of the Western Mediterranean, causing turtles to reach sexual maturity earlier when they’re thousands of kilometers away from their ancestral, eastern rookeries.
- These new loggerhead nesting sites have resulted in conflict between the turtles and the many beach clubs that occupy Italy and Spain’s coastlines; light pollution in these areas also poses risks to hatchlings.
- As the Mediterranean continues to warm, scientists are rushing to identify which beaches pioneer turtles will choose next and to establish protective measures before the animals arrive on crowded shores.
ASCEA and CASTEL VOLTURNO, Italy, and BARCELONA, Spain — In the early hours of a warm July day, regular rows of still-folded sun umbrellas stand along the shores of Castel Volturno, a coastal town in the Italian region of Campania, located about 35 kilometers (22 miles) northwest of Naples. A small group gathers around a control screen while a drone flies along the coast, searching for tractor-like tracks emerging from the waves. At the slightest sign, group members will quickly reach the location and fence off the area.
Summer is the nesting season for the loggerhead sea turtle (Caretta caretta). Loggerheads inhabit warm portions of the Atlantic, Pacific and Indian oceans, as well as the Mediterranean Sea. However, despite its broad range, the species is listed as vulnerable to extinction by the IUCN. These large marine reptiles spend roughly two decades maturing at sea before the females return to land — usually to the same beaches where they hatched — to lay their own eggs.
Historically, loggerhead nesting in the Mediterranean has been concentrated in the warm sands of the sea’s eastern and central basins — primarily in Greece, Türkiye, and Cyprus — while the western basin has served mainly as a foraging ground by juvenile turtles. But over the past five decades, increasing numbers of nests have begun to appear in the western basin, including on the shores of Italy, France, and Spain.
In Calabria, Italy, signs of loggerhead nesting activity were first found in the early 2000s, gradually expanding northward all the way to the French coast and westward to Spain, according to researchers. In Spain, where the first confirmed nest was documented in 2001, regular annual nesting began in 2014.
“In the Western Mediterranean, we are observing an expansion of the population in real time,” Sandra Hochscheid, a researcher at the Stazione Zoologica Anton Dohrn in Naples, tells Mongabay. “For the first time in history, we are witnessing the new colonization [by this species] along this coast.”
What began as an occasional anomaly has evolved into a permanent geographical shift, Hochscheid says.
As loggerhead turtles’ range expands, their search for suitable nesting habitat collides with some of the most heavily developed coastlines in Europe. To protect and conserve loggerhead sea turtle populations in the Western Mediterranean, an international conservation initiative co-financed by the EU LIFE program — the European Union’s main funding instrument dedicated to environmental, nature conservation, and climate action policies — and coordinated by the Italian environmental NGO Legambiente, launched in 2023 the Life Turtlenest project, which includes partner organizations across Italy, Spain, and France.
Migrants scouting new shores
Over the past few years, Hochscheid has been investigating why the turtles are expanding their nesting range. She does this by deploying satellite-linked transmitters on wild adult females immediately after they lay their eggs, to track their movements out at sea. She and her team have also attached trackers to captive-reared juveniles before releasing them to determine where this new population ends up during its early life stages, and the role ocean currents play in its dispersal.
Previous studies by her team suggest that loggerhead sea turtles moving in western Italy’s Tyrrhenian Sea remain close to marine areas where food is abundant, and the new data from the transmitters support this hypothesis.
“Competition with other turtles might be a factor [for migrating] if the historical feeding grounds become overcrowded,” says Hochscheid, who has studied sea turtle behavior for more than three decades. “But in reality, we still don’t know exactly why this has happened in the first place.”
At the University of Barcelona, marine researcher Carlos Carrera’s team is also investigating why the turtles are expanding their nesting range, using genomic data to trace the origins of turtles that have established new nests in the Western Mediterranean. By analyzing DNA from tissue samples collected from adults and hatchlings during post-hatching nest excavations in Spain and Italy, his team has found that they likely dispersed from established populations elsewhere in the Mediterranean and even farther afield. “These turtles are related to those in Greece, Turkey, and the Caribbean,” Carreras, also part of the Life Turtlenest project, tells Mongabay.
He says many nests along Spain’s Mediterranean coastline are laid dangerously close to the water, suggesting these turtles are younger and less experienced than those nesting in Italy. While the Italian population has had a few more years to establish itself — and now has more experienced mothers digging nests higher up on the beach — those in Spain are still in the earliest stage of colonization.
Carreras hypothesizes that rising sea temperatures due to global warming are accelerating juvenile growth in the foraging grounds of the Western Mediterranean, causing turtles to reach sexual maturity earlier when they’re thousands of kilometers away from their ancestral nesting grounds.
Irene Alvarez de Quevedo, a researcher at the BETA Tech Center in Barcelona, agrees with Carreras. “[Early maturation] turned out not to be a problem because now our beaches are warm enough for nesting,” Alvarez de Quevedo tells Mongabay.
Also, both genetic sequencing and GPS-tracking data suggest that pioneer mothers like their new homes and return to the same beaches time after time. Researchers say that as new turtles hatch and they too return to their natal beaches to lay the next generation, new nesting colonies will become permanently established.
Clashing with humans
However, not everyone has celebrated the loggerhead expansion. In Italy, nearly 27,000 private beach clubs, or lidi (plural of lido), blanket roughly 43% of the peninsula’s beaches. In summer, when loggerhead turtles come ashore to nest, the Italian coast is a bustling playground of human activity. Beach clubs monopolize the sand with dense grids of sunbeds and umbrellas, with lights bright and music blaring into the early hours. Before dawn, in many places, tractors rake the sand beaches to clear debris, compacting the sediment and potentially even crushing shallow egg chambers.
When loggerhead sea turtles first began nesting in this region, commercial beach clubs often viewed conservation efforts with outright hostility, according to conservationists.
“At first, [lidi] gates were locked against us, and turtles’ tracks were erased, fearing that the presence of a nest could have negative impacts on their business,” Leda Tonizello, president of the Campania-based ELSA ETS environmental association, tells Mongabay.
Similar experiences have been reported in Calabria, where most of the conservation on the Tyrrhenian coastline is carried out under the direction of WWF Italy, as well as in Tuscany. “Lido operators would deliberately smooth over turtle tracks before morning patrols arrived,” says Francesca Capanni, an environmental scientist at the University of Siena.
However, due to the efforts of conservationists and civil society over the last few decades, there’s been a radical shift in how beach operators view the presence of nests, locals say.
“It’s the success of a coordinated work of many groups that, while generally having different overall goals, have all united for the sake of this charismatic animal,” Tonizello says.
Local business owners say these conservation efforts have even yielded commercial benefits. Pino Cappuccio, a lido owner in Ascea, a seaside resort town in Campania’s Cilento National Park, tells Mongabay that watching a turtle nesting or eggs hatching during dinner is an experience his guests won’t forget.
But hurdles to turtle survival remain. A study published July 2026 in the journal Mediterranean Marine Science by Hochscheid’s team found that 87% of nests in Campania were exposed to direct or indirect beachfront lighting in 2022 and 2023. Bright lights are problematic for sea turtles; they deter females from nesting and can confuse hatchlings, misdirecting them toward land instead of into the sea. The study’s authors write that because of these lights, 82% of the nests they surveyed needed active human intervention to prevent hatchling disorientation.
In response, some areas are instituting lighting regulations along beaches. The local municipality of Ascea, one of the nesting hotspots in Campania, collaborated with the Anton Dohrn institute to install turtle-friendly, low-intensity lighting along its seafront promenade. And starting in 2027, compliance with low-impact lighting standards will become mandatory for any business applying for a beach facility concession.
“In our changing world, environmental protection is also an economic strategy,” says Stefano Sansone, mayor of Ascea.
Next steps
In late August in Castel Volturno, volunteers and researchers sit quietly, waiting with bated breath for the next generation of loggerheads to hatch. At last, after a few sleepless, disappointing nights, dozens of newborns begin to emerge from the sand. Then the work begins as the group takes measurements and collects other data for each tiny turtle, before releasing them into the sea.
As the Mediterranean continues to warm, scientists are rushing to identify which beaches pioneer turtles will choose next, and to establish protective measures before the animals arrive on crowded shores.
In Spain, Alvarez de Quevedo is also studying the thermal profile of the coastline, linking air and sea surface temperatures to ground conditions to assess which beaches are warming enough to support the development of loggerhead eggs. In doing so, she says she hopes to build predictive models to evaluate future beach suitability to inform management decisions.
In Italy, Capanni is analyzing the physical and chemical properties of sand collected during post-hatching nest excavations. She evaluates sand grain size distribution across all Tuscan beaches where nesting has occurred, as granulometry directly dictates gas exchange, moisture retention, and how easily female turtles can dig their egg chambers. She also tests sand and tissue samples for persistent organic pollutants to verify that prospective nesting sites are free of toxins.
“This is finalistic in trying to prioritize which beaches or environments are most important for the conservation of this species,” Capanni says. “If temperatures continue to rise, and previously suitable environments become less so, potential habitats narrow. It is critical to understand where they are and conserve them starting right now.”
Banner image: A large male loggerhead sea turtle, Ningaloo Reef, Western Australia. Image by Lewis Burnett / Ocean Image Bank.
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Citations:
Mingozzi, T., Masciari, G., Paolillo, G., Pisani, B., Russo, M., & Massolo, A. (2006). Discovery of a regular nesting area of loggerhead turtle Caretta caretta in southern Italy: A new perspective for national conservation. In D. L. Hawksworth & A. T. Bull (Eds.), Biodiversity and conservation in Europe (pp. 277-299). Springer. doi:10.1007/978-1-4020-6865-2_20
Hochscheid, S., Maffucci, F., Abella, E., Bradai, M. N., Camedda, A., Carreras, C., … Tomás, J. (2022). Nesting range expansion of loggerhead turtles in the Mediterranean: Phenology, spatial distribution, and conservation implications. Global Ecology and Conservation, 38, e02194. doi:10.1016/j.gecco.2022.e02194
Tomás, J., Mons, J. L., Martín, J. J., Bellido, J. J., & Castillo, J. J. (2002). Study of the first reported nest of loggerhead sea turtle, Caretta caretta, in the Spanish Mediterranean coast. Journal of the Marine Biological Association of the United Kingdom, 82(6), 1005-1007. doi:10.1017/S0025315402006537
Mancino, C., Canestrelli, D., & Maiorano, L. (2022). Going west: Range expansion for loggerhead sea turtles in the Mediterranean Sea under climate change. Global Ecology and Conservation, 38, e02264. doi:10.1016/j.gecco.2022.e02264
Chimienti, M., Blasi, M. F., & Hochscheid, S. (2020). Movement patterns of large juvenile loggerhead turtles in the Mediterranean Sea: Ontogenetic space use in a small ocean basin. Ecology and Evolution, 10(14), 6978-6992. doi:10.1002/ece3.6370
Acampa, F., Maffucci, F., Pasanisi, E., Hochscheid, S., Farina, M., Moura, É., … Arcangeli, A. (2025). Occurrence of loggerhead sea turtles in the offshore areas of the central-southern Tyrrhenian Sea (western Mediterranean): Results of the first five years of surveys using passenger ferries as observation platforms. Biologia Marina Mediterranea, 29(1), 27-30. doi:10.82008/bmm.v29i1.285
Marín-Capuz, G., Crespo-Picazo, J. L., Demetropoulos, S., Garrido, L., Hardwick, J., Jribi, I., … Carreras, C. (2025). Incipient range expansion of green turtles in the Mediterranean. Molecular Ecology, 34(11), e17790. doi:10.1111/mec.17790
Carreras, C., Pascual, M., Tomás, J., Marco, A., Hochscheid, S., Castillo, J. J., … Cardona, L. (2018). Sporadic nesting reveals long distance colonisation in the philopatric loggerhead sea turtle (Caretta caretta). Scientific Reports, 8, 1435. doi:10.1038/s41598-018-19887-w
Luna-Ortiz, A., Marín-Capuz, G., Abella, E., Crespo-Picazo, J. L., Escribano, F., Félix, G., … Carreras, C. (2024). New colonisers drive the increase of the emerging loggerhead turtle nesting in Western Mediterranean. Scientific Reports, 14, 1506. doi:10.1038/s41598-024-51664-w
Mancino, C., Rees, A., Hochscheid, S., & Maiorano, L. (2026). From patchy records to basin-wide insight: Integrating six decades of Mediterranean sea turtle nesting data. Biological Conservation, 322, 112078. doi:10.1016/j.biocon.2026.112078
Cardona, L., San Martín, J., Benito, L., Tomás, J., Abella, E., Eymar, J., … Marco, A. (2023). Global warming facilitates the nesting of the loggerhead turtle on the Mediterranean coast of Spain. Animal Conservation, 26(3), 365-380. doi:10.1111/acv.12828
Moura, É., Maffucci, F., Roncari, C., Farina, M., Teti, R., & Hochscheid, S. (2026). Will-o’-the-wisps on sea turtle nesting beaches: Will light pollution prevent new colonisation of the Western Mediterranean? Mediterranean Marine Science, 27(2), 459-468. doi:10.12681/mms.40434
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