Skip to main content
School of Biological and Chemical Sciences

Loggerhead turtle conservation: empowering NGOs through research

Tagging a nesting loggerhead turtle in Cabo Verde

Christophe Eizaguirre

Deputy Dean for Research Impact (Faculty of Science and Engineering)

The loggerhead turtle faces risks of extinction. A Queen Mary research project in Cabo Verde has seen local numbers soar, offering a sustainable way to protect this fascinating species.

The loggerhead turtle (Caretta caretta) is threatened with extinction. They face threats from coastal development, tourism and illegal poaching for meat, as well as from entrapment in fishing nets.

The islands of Cabo Verde (400 miles west of Senegal) host the third largest population of this species, and the largest in the North East Atlantic Ocean. This population represents 20-25% of the global numbers of this endangered species, making their protection of local and global importance.

The islands are home to nesting groups of different sizes who are exposed to different environmental and anthropogenic pressures, highlighting the need for locally targeted conservation strategies.

What did the researchers examine?

Since 2013, Dr Eizaguirre and his colleagues at diverse NGOs have studied nine out of 10 of the Cabo Verde islands (see Figure 1). Their findings cover over 110 km of the turtles' nesting beaches, around 65% of the available habitat in Cabo Verde. They not only studied the population structure and the distribution of the turtles' genetic diversity across the islands, but also examined their diverse feeding strategies.

Because loggerhead turtles face different threats at different life stages, Dr Eizaguirre, in collaboration with the University of Cabo Verde (Uni-CV) and the Institute of Marine Research (iMAR), conducted research that focused both on nesting females (the current reproductive population) and also investigated the movement and associated threats faced by hatchling turtles (the next breeding generation) once in the ocean.

Following baby turtles to sea

Dr Eizaguirre's team used acoustic tags with high-resolution ocean modelling to determine the dispersal patterns of neonate turtles. The results showed that dispersal trajectories coincide with major fishing grounds. For the first time, they were able to quantify the swimming capacity of hatchlings and their frenzied behaviour as they rapidly escape coastal waters. This research highlights the need to determine marine areas that need protection and so increase hatchling survival rates and build future generations.

Loggerhead turtle hatchlings are released after being tagged

Ancient history

Dr Eizaguirre and his colleagues also gathered and sequenced DNA samples from over 4,000 turtles. This data allowed his team to reconstruct the colonisation history of the loggerhead turtle across the Atlantic Ocean and establish the importance of the Cabo Verde archipelago. Remarkably, they found that Cabo Verde acted as a stepping-stone for two waves of colonisation: the first about three million years ago with a later event, probably after the last glaciation.

These two waves of colonisation can be seen in two distinct groups of genetic variants in the turtles, which are today distributed in a non-random way across the islands. The rarer variants, linked to the more recent colonisation event, are found where nesting density is low (São Vicente) and also where there is particular pressure from poaching (Boa Vista, São Vicente). Dr Eizaguirre's discovery of other variants showed that, contrary to previous thought, there wasn't a single homogenous loggerhead turtle population on Cabo Verde. Instead, the population is composed of independent nesting groups (turtles on the blue, green, red and orange islands in Figure 1) with their own unique genetic diversity, each requiring specific protection.

Figure 1: The Cabo Verde archipelago, off the west African coast (circle) has distinct genetic populations of turtles (represented by island colours), with specific behavioural traits – a key discovery of Dr Eizaguirre’s research. Population size estimates are based on the number of detected nests (average 3.5 nests per turtle).

TurtleBase: sharing knowledge

A standardised field protocol has been central to providing a reliable census of sea turtles and their nesting on Cabo Verde, allowing 'previously impossible' comparisons of the nesting groups on different islands to take place.

The data from Dr Eizaguirre's protocol is summarised in TurtleBase, an open-source database which is the largest DNA database of a marine megafauna to date.

A remarkable resource, it contains data on over 6,000 individual tagged turtles, genomic resources and stable isotope information. The open source nature of this vast database makes it a vital resource for sea turtle conservationists all over the world.

Vital international funds

Dr Eizaguirre's discovery of the Cabo Verde turtle population’s genetic diversity and population structure has had far-reaching consequences.

Significantly, it contributed to the International Union for the Conservation of Nature's (IUCN) decision to change its assessment of the Cabo Verde turtles in 2015. At a global level, the loggerhead turtle has 'Vulnerable' status but locally this was elevated to 'Endangered'. This allows Cabo Verde Non-Government Organisations (NGOs) to benefit from vital international conservation funds and transforms their ability to protect the species.

The importance of small groups

Dr Eizaguirre's research highlighted the importance of Cabo Verde's small nesting groups, leading to a new turtle conservation management strategy. Previously, conservation efforts had focused on the main nesting group of turtles on Boa Vista, the island with the highest nesting density, neglecting these smaller groups.

A loggerhead turtle camouflaging its nest

Creating citizen scientists

Communication has been central to conservation strategy. In 2013, together with partner NGOs including Turtle Foundation and Project Biodiversity, Dr Eizaguirre established a nationwide community-based programme to help protect the loggerhead turtles. This new conservation strategy aimed to protect all turtle groups, including smaller populations. Public engagement and awareness lies at its heart, building a generation of citizen scientists.

One of the largest conservation programmes for marine megafauna in the world, the project is a collaboration between local communities, researchers and NGOs. University students were recruited as project 'ambassadors', who in turn recruited local volunteers. Dr Eizaguirre's team have helped these volunteers to build their knowledge of turtle conservation and shared their knowledge, field equipment, funds and resources – with stunning results.

The project has been welcomed by 24 coastal communities and has engaged with more than 300 local volunteers. Whereas previously military personnel used to patrol beaches at night during the nesting season, now local volunteers, led by NGOs and ambassadors, patrol and protect the turtles from poaching – and also collect scientific data.

In this way, the research has contributed to a sustainable infrastructure to share and disseminate knowledge about the turtles – an exchange of knowledge that has influenced attitudes, raised awareness of the small turtle populations and significantly reduced illegal poaching.

This programme has won praise from the Director of the National Environment Office and was a finalist at the UK National Coordinating Centre for Public Engagement awards in 2016.

Dr Eizaguirre's team also make use of modern technology in their public engagement strategy. In 2018, they co-created Atlantis, a simulation tool which uses real data to visualise the turtles' movements and behaviours. It is also a powerful educational tool used to raise awareness of the threats faced by sea turtles and other marine life – from poaching to plastic pollution. In 2021, Atlantis won an iF Design Award for User Experience.

Building an eco-tourism economy

The growth of nesting turtle populations has been mirrored by a rise in eco-tourism.  As well as helping to prevent poaching, the citizen-science programme has enabled local people to find alternative sources of income. For example, on the island of Maio 11 communities benefit from this programme, which in turn helps them raise new income.

Eco-tourism hasn't only brought benefits to the local population: it has also driven the sustainability and growth of turtle populations. In 2019, two agreements were signed between a local conservation group and two eco-tourism companies, allowing tourists to visit nesting beaches on the island of São Vicente. These beaches now have a greater turtle population and predictable turtle activity, while tourists can enjoy watching the loggerheads in their natural habitat.

As well as helping to prevent poaching, the citizen-science programme has enabled local people to find alternative sources of income.

Soaring numbers

In fact, turtle numbers in Cabo Verde haven't just risen as a result of these conservation strategies: they've soared.

The loggerhead population has rocketed (Figure 1). For example, in 2007 there were estimated to be 3,133 turtles on Boa Vista, but by 2020 this had risen to 41,965. Indeed, across all of the islands, turtle populations are growing fast – including the small, rare and most threatened unique nesting groups on São Vicente, where nesting turtle numbers have risen from 28 turtles in 2009 to over 700 in 2020.

A turtle success story

This dramatic increase in turtle numbers on the islands has benefited local people, tourists from around the world – and global efforts to conserve biodiversity.

By working collaboratively and engaging local organisations and communities in the drive to protect the turtles, researchers have contributed to a sustainable future for vital conservation work, raised public awareness of the importance of protecting sea turtles, and created lasting economic opportunities for the people of Cabo Verde.

Schools, institutes and research centres

School of Biological and Chemical Sciences

We are home to an active and multi-disciplinary research programme. Our research staff are engaged in a wide range of projects across the broad sweep of biological, chemical and psychological sciences.

Evolutionary Genetics and Genomics

Our research focuses on the ecological and evolutionary aspects of population divergence, speciation and hybridisation. We have a particular strength in genomics.

Eizaguirre Lab

Conservation biology is one of the rare fields of biology where evolution has been too often neglected. In our lab, we aim to combine the fields of evolutionary and conservation biology to demonstrate the necessity to consider evolutionary  theories in conservation programs.