Sea turtles in Indonesian waters have different genetic “fingerprints”. This discovery is crucial for protecting them with more effective conservation strategies.
Behind their hard shells and graceful swimming movements as they glide through the waves, sea turtles harbour a secret within them genetic traces that are invisible to the naked eye but hold the key to preserving them more carefully.
“Until now, sea turtle conservation has largely relied on visual approaches such as counting nests, monitoring nesting sites, and estimating populations,” said Dr Beginer Subhan, a researcher from the Department of Marine Science and Technology at the Faculty of Fisheries and Marine Sciences (FPIK), IPB University.
However, Dr Beginer added that these methods have not been able to answer the big questions about the origins and relationships between populations separated by distance, time, and even ocean currents. Now, through genetics, the story hidden for thousands of years is beginning to unfold page by page.
He noted that genetics can serve as a window to trace the lineage of sea turtles, from their ancestors to the degree of connection between closely related groups across islands.
“With accurate genetic mapping, conservation is no longer just about saving, but also reconnecting the threads of life that have been scattered and silently severed” he said at an event held by the Disaster Management Centre of Dompet Dhuafa recently.
Dr Begin mentioned two studies conducted by IPB University to map the genetics of sea turtles in Indonesia. In 2024, he and his team studied hawksbill sea turtles (Eretmochelys imbricata) in the Java Sea region. They analysed a specific DNA segment called the d-loop from 152 sea turtles that laid eggs at six different locations.
The results were surprising. Twenty types of haplotypes, or “genetic fingerprints”, were identified, with 13 of them being discoveries, highlighting the extraordinary genetic diversity of Indonesian hawksbill sea turtles.
Even more intriguing, some of the haplotypes found in Indonesia were also found in Malaysia and Australia. This suggests cross-border genetic connections, implying large-scale sea turtle movements spanning thousands of kilometres, yet still returning to their original nesting sites. “These sea turtles might be ‘travelling’ far, but they remember the way back. That’s remarkable,” said Dr Begin.
For him, this finding opened his eyes to the importance of cross-border conservation cooperation. Sea turtle populations do not recognise national borders, but they move according to currents, temperatures and the instincts of their ancestors. That is why he emphasises that international conservation agreements must take this genetic connectivity into account.
Meanwhile, another study on olive ridley sea turtles (Lepidochelys olivacea) in 2020 also revealed an equally fascinating genetic story. One of the focal points was Cendrawasih Bay, an eastern Indonesian region known as an underwater paradise. In this area, the team found that sea turtle populations from Kwatisore and Yapen Island have different genetic compositions despite being geographically close.
What caused this difference? It turns out that the answer is ocean currents. During the northwest monsoon season, ocean currents act as a natural barrier, preventing genetic exchange between populations. As a result, sea turtles from one region and another evolve along their evolutionary paths. They are like two siblings living in different villages and growing up with their own cultures.
This mapping even divides the hawksbill turtle population into several clades. One major clade consists of five locations in western Indonesia, such as Aceh, Pariaman, Panggul, Serangan, and Tuafanu, and has a genetic connection with populations from India. Meanwhile, another clade is found in eastern Indonesia, namely Kapoposang, Yapen Island, and Cendrawasih Bay.
Australia itself shares most of its haplotypes with Indonesia. “Imagine how amazing it is that a turtle that lays eggs on the coast of Papua has a genetic link with its ‘distant cousin’ on the west coast of India,” said Dr Begin.
These findings are not merely scientific notes. They send a clear message: conservation cannot be standardised. Populations of turtles with different genetics naturally require different approaches. It is like prescribing medicine not all patients can be cured with the same prescription.
Conservation efforts, which have long relied on a generalised model, now need to be more precise. In areas with high genetic diversity, conservation strategies must focus on preserving variation to prevent it from disappearing. Conversely, in regions with low genetic exchange, approaches are needed to maintain population sizes and prevent them from declining due to inbreeding or low numbers of individuals.
“This fact reminds us that our sea turtles can no longer be treated as a single population. They are unique. They each have their own genetic identity. And if one population becomes extinct, for example, in Cendrawasih Bay, then the haplotype that only exists there could be lost forever. Populations from Aceh cannot replace it, let alone Australia. This is the urgency of genetics-based conservation,” said Dr Begin.
Knowledge of this genetic structure opens the door to developing more targeted and sustainable conservation plans. These efforts not only protect the environment but also touch on local economies, coastal cultures, and the tourism industry that relies on the beauty of the sea.
With this approach, Dr Begin concluded, conservation is no longer merely about keeping sea turtles alive but ensuring they remain an integral part of the intact, sustainable tropical marine symphony, passed down to future generations. (*/Rz) (IAAS/EXC)