Over 1,700 new hatchlings of Caretta caretta were born in Calabria during the breeding season that has just come to a close, offering further hope for the future of this charismatic and threatened species — a symbol of the Mediterranean, classified as "vulnerable" on the Iucn Red List. In total, 35 nests were recorded in Calabria in 2019; in particular, the stretch of Ionian coastline in the province of Reggio Calabria, which represents the most important Caretta caretta nesting site in Italy, hosted 28 nests, found and protected by the non-profit organisation Caretta Calabria Conservation, founded specifically to survey and protect the nests of these marine reptiles.

In search of nests

Finding and monitoring Caretta caretta nests, particularly along a still wild and largely inaccessible stretch of coastline such as that of the province of Reggio Calabria, is no easy task. This year too, however, the Calabrian conservation association succeeded in its mission, ensuring that more than 1,700 hatchlings reached the sea, "thanks to the tireless work of around eighty people — including participants in research and training camps, dissertation students and interns from across Italy — coordinated by specialist staff authorised by the Ministry of the Environment," as stated in a press release from the NGO.

Researchers and volunteers searched for tracks and nests through daily beach patrols, also making use of drones and electric-assist fat bikes. In addition to surveying the nests, the association's staff is responsible for securing each clutch, relocating nests laid too close to the sea, and artificially incubating eggs found in particularly unfavourable environmental conditions.

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A good season

The figures recorded confirmed the extraordinary importance of the Reggio Calabria Ionian coast for the loggerhead sea turtle, but data from the rest of Italy were also encouraging. "Overall the season went well compared to last year," said Salvatore Urso, naturalist and founding member of Caretta Calabria Conservation. "Nearly a hundred nests were surveyed and, given that they are not searched for everywhere, the hundred mark has certainly been exceeded. It is also true that making a comparison with previous years is not straightforward, since in the past the available data were fewer and far more fragmented. As regards the Reggio Calabria Ionian coastline, the number of nests is stable and over 70 per cent of the eggs laid hatched successfully."

The climate has not (yet) affected nesting

The summer of 2019 was very hot; in particular, the month of July was, according to the European Copernicus programme, the hottest ever recorded in the past 140 years. Nevertheless, the Caretta caretta breeding season would not appear to have suffered as a result. "Temperatures did not deviate much from the already high seasonal averages," explained Salvatore Urso. "In Calabria there are some beaches where the average temperature can reach 32–33 degrees; it is not a new phenomenon. The important thing is that it does not exceed 35–36 degrees, the temperature at which embryo death occurs."

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Rising temperatures may nonetheless represent a serious long-term threat. "If the temperature exceeds 29 degrees, only females are born, and the sex imbalance can worsen. The number of males is already very low, being born from early or late nests, when temperatures are lower; male individuals are moreover more vulnerable, as these are nests with a low hatching success rate."

What the anomalous Pesaro nest tells us

We finally asked the Caretta Calabria Conservation naturalist whether the nest found on the beach of Baia Flaminia in Pesaro — which is the northernmost sea turtle nesting site ever recorded in Italy — is a positive sign indicating the expansion of the species, or rather a negative symptom of rising temperatures. "Neither one nor the other," clarified Salvatore Urso. "At that latitude, but on the Tyrrhenian side, nestings have already been reported, for example in France and Corsica. Caretta caretta is a philopatric species and therefore tends to return to the same location."

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"It is unlikely that turtles change their habits in response to environmental change; they are creatures of habit, stubborn to the point of returning to the same site even when it has almost ceased to exist, as observed on some particularly eroded beaches." In any case, Urso concluded, it is probable that the species frequented this stretch of coastline in the past as well; after all, sea turtles are widely distributed across the northern Adriatic, but today, thanks to growing interest in conservation and the greater number of people present on beaches, spotting a nest may be easier.