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Sea Turtles in Cabo Verde
Sea turtles have been roaming the Earth for over 150 million years. During this time seven different species evolved separately and became what we know today as sea or marine turtles. They have played, and still play, an important role in our oceans, maintaining different marine ecosystems healthy and in balance. However, during the last 100 years sea turtles are facing different anthropogenic threats that are jeopardising their survival. The Red List of Threatened Species from the IUCN (International Union for the Conservation of Nature) includes 6 of the 7 species of sea turtles. The status of the other species, the Flatback turtle, is unknown.
A Species Under Threat
Over the past centuries, sea turtles have been facing growing human threats. Today 6 out of 7 species are listed as threatened on the IUCN Red list. The status of the 7th species, the flatback turtle, remains unknown.
Loggerhead turtle
Scientific Name: Caretta caretta
Carapace Size: 62-100 cm (SCL)
Diet: Omnivores
Fun Fact: They get their name from their large head that helps crush mollusks
Olive Ridely Turtle
Scientific Name: Lepidochelys olivacea
Carapace Size: 60-72 cm (SCL)
Diet: Omnivores
Fun Fact: Synchronous mass nesting events in few locations (Arribada)
Leatherback turtle
Scientific Name: Dermochelys coriacea
Carapace Size: 120-180 cm (SCL)
Diet: Jellyfish
Fun Fact: Largest sea turtle in the world only feeding on jellyfish
Hawksbill turtle
Scientific Name: Eretmochelys imbricata
Carapace Size: 53-114 cm (SCL)
Diet: Sponges
Fun Fact: Feed on sponges that are deathly for most species
Green turtle
Scientific Name: Chelonia mydas
Carapace Size: 81-124 cm (SCL)
Diet: Omni to herbivores
Fun Fact: Juveniles feed on the reefs around the Cabo Verdean islands
Cabo Verde is the main nesting site for loggerheads in the eastern Atlantic — probably the largest in the world!
This map shows the loggerhead sea turtle distribution around the world, noting that the annual numbers of nesting females on Sal Island are larger the whole Mediterranean population.
Despite that the global status of loggerhead sea turtles was downgraded in 2015 from endangered to vulnerable, the Northeast Atlantic subpopulation (Cabo Verde) was left as endangered. In 2011, the IUCN Marine Turtle Specialist Group listed this subpopulation as one of the eleven most threatened populations of sea turtles in the world. Given the high philopatry of female sea turtles (fidelity to their breeding site) and the extremely slow dispersion to different nesting sites, Cabo Verde is essential for the reproduction of loggerhead turtles.
You can read more about the loggerhead turtles of Cabo Verde in a SWOT report (The State of the World’s Sea Turtles) Cabo Verde: Sea Turtles “In Abundance”.
An Average Adult Loggerhead Turtle in Cabo Verde
80cm aprox
90-100kg.
82 eggs
45-50 years aprox
The Consumption of Sea Turtles in Cabo Verde
In Cabo Verde, the consumption of sea turtle meat is a long-standing tradition, as is the consumption of eggs on some islands and the hunting of males for aphrodisiacs. In 1987, the hunting of sea turtles was banned during the nesting season in Cabo Verde; in 2002, it was banned during the whole year; and in 2005, possession, hunting, consumption and exploitation of sea turtles and their eggs became explicitly prohibited by law.
In 2018, the Government, with the support of all political groups, approved a new law, the Special Regime for the Protection and Conservation of Sea Turtles, that criminalises all illegal activities and settles the foundations for sea turtle conservation in Cabo Verde. More recently, in 2024, the government approved the special regulation for the execution of sea turtle watching excursions, setting the baselines for the sustainable touristic exploitation of nesting turtles. Despite government regulations, the killing of adult sea turtles is still a problem seen across the country.
Life of a Sea Turtle
Sea turtles have a long and complicated life cycle. They will only reach maturity after 20 – 25 years; when they do, they will only breed every 2-3 years until they are around 45 – 50. During the early stages, they are very vulnerable.
The eggs are laid under the sand and are exposed to many natural and anthropogenic threats. There is no maternal care, and this means that the newborn turtles (or hatchlings) will start their life journey alone. Hatchlings and juvenile turtles will face predation and other threats; even adult turtles will battle against poaching and marine pollution. In the end, only 1 in 1,000 hatchlings are estimated to become adults.
Remarkable Navigational Abilities
Probably, one of the most amazing thing about sea turtles is their ability to find their way back after spending 20 years around the ocean. It is mostly accepted that they can follow the earth's magnetic fields to find the same location where they hatched, although other mechanisms may also help. They can also move to new nearby locations, always looking for quiet places with good nesting conditions.
How Temperature Determines Sea Turtle Sex
Sea turtles don't have sexual chromosomes like mammals. Instead, their sex is determined by the temperature of the eggs' incubation, something called TDS (Temperature-Determined Sex). Nests that were incubated at lower temperatures may produce more males, while warmer temperatures will increase the females' numbers. Although the pivotal temperature varies within different populations, 29ºC marks the average of a balanced incubation temperature. Our team, together with the Eizaguirre Lab from Queen May University of London, have been researching the potential mechanisms of adaptation of sea turtles against climate change, filling this crucial knowledge gap that will determine the next steps for sea turtle conservation.
The Importance of Sea Turtles
Like all megafauna, sea turtles keep their natural habitat healthy, intervening in different steps of the food chain. However, the disappearance of sea turtles and other keystone species from our oceans disrupts the balance of marine ecosystems.
This, ultimately, has a huge social and economic impact on humans.
Coral Reefs
Some species of sea turtles feed on sponges (hawksbills) and algae (greens) that compete with coral for space and suffocate them. Keeping their numbers under control allows coral to grow and expand. Remember that coral reefs are one of the most important ecosystems on earth!
Seagrass Beds
Green turtles are the gardeners of the oceans. They feed on seagrass, keeping it healthy, just like we do with lawnmowers. Seagrass beds are nurseries for many fish species, giving them shelter against predators. They also stop the erosion against storms of shallow seabeds.
Recycling of Nutrients
Loggerheads have powerful jaws capable of crushing seashells. Through the tiny bits of shells and their faeces, sea turtles increase the rate of nutrient recycling in benthic and ocean bottom ecosystems.
Food Source
Hatchlings form part of the diet of different animals like fish, crabs, sharks, seabirds and even other terrestrial mammals. Remember, only 1 in 1,000 baby turtles will survive!
Maintaining Balance
Leatherbacks are one of the few predators of jellyfish, which eat fish larvae. The lack of leatherbacks will increase jellyfish blooms, which could decrease certain populations of fish, some of them of commercial interest.
An Impact Beyond Marine Ecosystems
Sea turtles are, therefore, very important for different ecosystems, and many other species depend on them. Another important aspect of sea turtles is that they can help prevent some impacts of climate change in coastal communities. Having strong and healthy dune systems and coral reefs will prevent coastal areas from becoming flooded due to sea level rise and due to an increase of extreme weather events like hurricanes.
From a broader perspective, we will see that all the roles that sea turtles play in the marine ecosystem have some direct or indirect benefits for humans. However, they also have an important socioeconomic impact on coastal communities where they nest. Through ecotourism, conservation and research, hundreds of Cabo Verdeans are employed every year.
In 2016 the network for sea turtle conservation of Cabo Verde, TAOLA, led by Project Biodiversity, prepared a study on the socioeconomic impact of sea turtles in Cabo Verde. In 2016, almost 900,000€ were generated through “turtle watching” excursions and the employment of staff from all the NGOs working in the field in Cabo Verde. Nowadays, this number is expected to have increased considerably.
What is Threatening Sea Turtles?
Sadly, humans are responsible for 99% of species extinction in the world. Recent studies found that the current extinction rate is between 1,000 and 10,000 times higher than the “normal” extinction rate (background rate). While before, only 0,1 species from every million went extinct yearly, now this number is at least 100 in every million species.
With sea turtles, it is so different; human-driven or anthropogenic threats are the leading causes of the decrease in their populations. In Cabo Verde, as well as in many other places in the world where turtles nest, we can list those threats as follows:
Conservation Practices
Until recently, little was known about the health and conservation status of the loggerheads on Sal. As a key species, sea turtles can assist in piecing together important information about the health of the surrounding ecosystem and environment. With both local and international partners, we have been able to extend our knowledge on this species and implement conservation practices with the community.
Beach patrols
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Night patrols on foot to prevent poaching on nesting beaches, both by our staff and in collaboration with the military and community associations;
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Night drone patrols on nesting beaches covers more ground and allows protection of less accessible beaches to deter poaching and stray dog presence;
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Weekly patrol on all beaches to monitor nesting and poaching activity throughout the island.
Scientific Research
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Collection of biometric data to research population trends;
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Utilisation of microchips and GPSs on nesting turtles to collect reoccurrence data when they come back to nest;
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Collection of biological samples to study the genetic distribution of loggerheads in Cabo Verde – led by Queen Mary University of London;
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Record of sand and nest temperatures throughout the season to study the implications of climate change on the loggerhead population;
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Studies of the impacts of light pollution in hatchling dispersion and how to minimize it
Mitigation tools - hatcheries
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Relocation of endangered nests to safer places on the beach, and to hatcheries, where they are not affected by light pollution;
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Monitoring of hatch success in hatcheries to understand and improve relocation techniques;
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Promotion of talks at the hatcheries with visitors to promote environmental conservation.
Habitat restauration
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Restoration of dunes in protected areas to improve the environmental quality on the nesting beaches, reducing light pollution impacts;
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Beach and underwater clean-ups to ensure cleaner beaches for nesting loggerheads;
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Partnerships with the tourism business to implement turtle-friendly approaches such as reduced lights to reduce beach front light pollution.
Outreach & Community partnerships
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Promotion of environmental education in schools and community centres;
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Training of tour operators to conduct turtle-friendly tours
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Partnering with community associations such as Guardians of the Sea to minimise bycatch of turtles, voluntary beach patrols and more
Turtle Conservation For Volunteers
Join Project Biodiversity for an amazing opportunity to visit Cabo Verde, where you can help our team protect and preserve critically endangered loggerhead turtles as they nest. This unique opportunity allows you to work closely with dedicated local rangers and fellow volunteers to safeguard these magnificent creatures in the vital conservation effort.
As part of a focused, small group, you'll have the chance to witness the nesting populations of female turtles across Sal’s different beaches. These female turtles are crucial to the species' survival, facing numerous threats in Cabo Verde that you can help us mitigate.
Our expert field biologists will provide you with invaluable conservation knowledge and insights into Cabo Verde's diverse marine and terrestrial wildlife.
While many tourists visit our archipelago each year, few engage with the destination on a deeper level. If you're planning to travel this year, we urge you to consider this meaningful volunteer opportunity to significantly impact turtle conservation.
Protecting these beautiful creatures can be a life-changing experience. Our team is eager to welcome and guide you through this incredible journey!
Join us this year!
Adopt a Sea Turtle in Cabo Verde
Adopting a sea turtle is one of the most meaningful ways to support the work of Project Biodiversity in Sal, Cabo Verde! Your donation will allow you to adopt a hatchling for yourself or a loved one symbolically.
You'll get to select your turtle's name and birthday (hatch date). We will send you an email announcement when your turtle is born with her picture and your official personalised adoption certificate, which you can view here! It’s a beautiful gift for friends and family that you can be sure will make a difference!
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