A summer of turtles in Spain, with many new nesting sites identified

This summer has been a busy time for turtle scientists in Spain as there have been an unprecedented number of turtle nests along the country’s coasts. The species involved is the loggerhead turtle (Caretta caretta) which is listed as ‘vulnerable’ by the IUCN Red List, with a population trend that is decreasing globally. As waters and beaches in the western Mediterranean get warmer, female turtles are coming ashore in Spain, from Andalusia in the south to Catalonia in the north, to lay their eggs.

This summer alone, 27 nests were recorded, the most since the first loggerhead turtle nest was recorded on the Spanish coast in 2001 and there is reasonable speculation that this might be a trend driven in some way by changing climate. If it is, it would seem to show that the turtles are more adaptable than previously thought.  The nesting adults, the nests and the hatchlings are all vulnerable to disturbance and other human interactions and need to be carefully monitored and protected.

Turtle nesting behaviour

After mating, female loggerheads, like other marine turtles, head to a nesting beach to lay their eggs. This is usually the beach where they themselves hatched. The mother turtle hauls out of the sea and high onto the shore under the cover of darkness where she digs a deep hole in the sand using her rear flippers. She then deposits her round and soft-shelled eggs into the hole. The size of a clutch can vary greatly but the average size is 100 eggs. After covering the nest with sand, she retreats back to the safety of the sea.

Loggerhead turtles on the Spanish coast

Loggerhead turtles have nested along the Mediterranean coast of Spain in the past but not to the extent that has been seen in 2023. This summer 27 nests have been recorded, including in places where turtles have never previously nested and where they are very close to human activities. There have been 10 nests in Catalonia, 8 in Valencia, 2 in Murcia, 2 in Andalusia and 5 in the Balearic Islands. There may have been more nests which have not been identified. Between 2010 and 2022, only 38 nests were recorded in mainland Spain and the Balearic Islands, so it is clear to see that this year is a special year and time will tell if this is a trend that will continue.

Why have so many female turtles chosen the Spanish coast for their nests? It all comes down to temperature. In the past, the beaches were too cold but now, as temperatures in the western Mediterranean increase, warmer waters and beaches mean that female loggerheads are staying in this area to lay their eggs.

Protecting turtle nests

Protecting the turtles is a collaborative project in Spain. Scientists work closely with local police, town councils, volunteer groups and the public to ensure that the females can dig their nests and lay their eggs undisturbed before the work of protecting the nest begins. From the day that the eggs are laid, it takes about two months until the eggs hatch, so the nest needs to be well protected and monitored during that time.

As an endangered species, every nest, every egg and every hatchling is valuable. Elena Abella and Irene Alvarez de Quevedo work for BETA Technology Centre at the University of Vic in Catalonia. With colleagues at the CRAM Foundation, they are working to ensure that the turtle nests on the Catalan coast are properly protected, monitored and studied so that the baby turtles have the highest chance of success when they hatch. “It has been a real surprise to have so many loggerhead turtle nests on our beaches this summer. Only one in a thousand hatchlings make it to adulthood, so here in Catalonia we are doing everything we can to give them a helping hand by making sure that the nests are properly protected during the incubation period,” says Elena.

“This year we have had a record number of nests in Spain whilst in Italy they have had over 400 nests which is also a record! With the changes we are seeing in the ecosystem including increasing temperatures, it is likely that there will be more turtle nests in the western Mediterranean in the coming years. So, it is really important that we learn to share our beaches with the turtles and to understand that they are habitats for protected species and not just places for us to enjoy in our free time,” adds Irene.

OceanCare supports turtle rescue and research

OceanCare has a long history of supporting turtle rescue and research in the Mediterranean through our partner organisations Alnitak and Equinac. Alexander Sánchez-Jones from Alnitak has also noticed changes in turtle distribution this summer, as well as changes for other species. He says that “in the Balearic Islands this summer, we have had fewer sightings of turtles and other species such as Risso’s dolphins and sperm whales. We can speculate that it is to do with higher sea surface temperatures, but we can’t be sure. As for loggerhead turtles, we have seen them but there seem to be a higher number of juveniles than usual. Our observations at sea are corroborated by the local stranding network who have found fewer turtles this year which are smaller than usual. Not so many are entangled in ghost gear as in previous years. This decrease in turtle sightings, alongside the higher amount of nesting turtles, makes this a strange year and reminds us how important it is to keep collecting data so that we can better understand what is happening.”

Globally, OceanCare supports the rescue of turtles through the Sea Turtle Rescue Alliance (STRA). STRA aims to connect and empower the sea turtle rescue and rehabilitation community worldwide. We also support the Olive Ridley Turtle project and its rescue centre in the Maldives.

What to do if you see a turtle

If you see an adult turtle on the beach it could be a nesting female:

• Alert the authorities (in Spain call 112, in Italy call 1530 or send a WhatsApp or text message to ++39 (0)349 2100989)
• Do not touch the turtle
• Do not take photos with flash or videos with lights
• Do not shine a light on the turtle
• Do not let the turtle see you
• Keep your distance

If you see baby turtles on the beach:

• Alert the authorities (in Spain call 112, in Italy call 1530 or send a WhatsApp or text message to ++39 (0)349 2100989) and follow any advice that they offer
• Do not take photos with flash or videos with lights

If you see turtle tracks in the sand:

• Alert the authorities (in Spain call 112, in Italy call 1530 or send a WhatsApp or text message to ++39 (0)349 2100989)
• Do not tread on the tracks

If you see a turtle at sea:

• Do not disturb it
• If it is injured or entangled in fishing gear, call the authorities (in Spain call 112, in Italy call 1530)
• Do not attempt to cut free entangled flippers. This must be done by a professional

If you see ghost gear (lost or abandoned fishing gear) in the Mediterranean Sea:

• Report it to Alnitak here: https://www.observadoresdelmar.es/Proyecto/Pesca-Fantasma/19

Sources and further information

Follow Caretta a la Vista! (Turtle in Sight!) on Instagram @carettaalavista for more information. Or check out their website.

Caretta a la Vista… call 112! Watch YouTube video (in English).

OceanCare – Guidelines on watching wildlife with kindness.

Casale and Tucker (2017) Caretta caretta. The IUCN Red List of Threatened Species 2017. https://www.iucnredlist.org/species/3897/119333622

Hochscheid et al. (2020) Nesting range expansion of loggerhead turtles in the Mediterranean: Phenology, spatial distribution, and conservation implications. Glob. Ecol. Conserv. 38: e02194.

Miller et al. (2003) Nest Site Selection, Oviposition, Eggs, Development, Hatching, and Emergence of Loggerhead Turtles. In: Bolten and Witherington (eds.) Loggerhead Sea Turtles. Smithsonian Press: Washington, DC, USA, pp. 125–143.