Line of action:

Status:

Execution date:

The loggerhead turtle (Caretta caretta) has temperature-mediated sex determination and high philopatry, so the future of the species in the face of a climate change scenario may depend on its ability to colonize new areas. This species nests in the eastern Mediterranean on beaches that will not be suitable in the future due to their high temperatures, according to several modelling studies.

However, in recent years sporadic nesting events of Caretta caretta have increased on the Spanish Mediterranean coast, with Catalonia being one of the autonomous communities where the most events have been concentrated. Thus, according to the University of Barcelona, our coasts may constitute in the future fundamental areas for the survival of this species in the Mediterranean.

In this way, the NIDOS-Caretta project has proposed to develop mechanisms to understand this increase, evaluate their success , establish optimized management protocols and raise awareness among the different sectors of society involved, with emphasis on the role of citizens in the conservation of this charismatic species.

The general objective of the project has been to carry out a pilot test in the autonomous community of Catalonia to maximize the success of sporadic nesting events of the loggerhead turtle (Caretta caretta), which may be applicable in the future and in other autonomous communities. This pilot includes a scientific study to understand the reason for this increase in nesting events, the development of optimized management mechanisms and an awareness of the sectors involved.

The specific objectives were as follows:

• Information and awareness of citizens regarding loggerhead turtle nesting events on the Spanish coasts.
• Improvement of nesting management and protection mechanisms on the coasts of the Spanish Mediterranean.
• Study and monitoring of nesting events of Caretta caretta.

• Activation of a pilot beach management plan based on optimal nesting areas, in Catalonia.
• Determination of the origin and genetic variability of sporadic nests.
• Study of incubation temperatures and biological and ecological characteristics of sporadic nests .
• Dissemination and communication of the project.

The loggerhead turtle (Caretta caretta) has temperature-mediated sex determination and high philopatry, so the future of the species in the face of a climate change scenario may depend on its ability to colonize new areas and produce females in nests. This species, which nests mainly on beaches in the eastern part of the Mediterranean, has increased sporadic nests on the Spanish Mediterranean coast in recent years. Thus, the Spanish coasts may constitute fundamental areas for the survival of this species in the Mediterranean.

This project has carried out a pilot test in Catalonia to maximise the success of loggerhead turtle nesting events with scientific studies and to understand why these events have increased and how this emerging colonisation is taking place. In addition, a proposal for a protocol for the management and protection of these nests has been carried out, as well as awareness-raising actions aimed at the different sectors involved.

To this end, it has participated in the management of all the nests on the Catalan coast during the years 2020 and 2021, registering a total of 22 nesting events in that period, 9 of which included a clutch and in 11 events the female could be observed on the beach. On the other hand, genomic studies have been carried out with offspring from the nests found between 2016 and 2019. Hatching success, the minimum number of males and females that have intervened in the events studied have also been studied, and multiple paternity has been observed in some nests.

Likewise, temperature sensors have been installed at different points, which has made it possible to determine that the increase in the detection of nesting events could be caused, in part, by an increase in the thermal conditions of the beaches, especially intense since 2010.