Indonesia Sea Turtle Project

Understand the turtle populations that live on Indonesia’s reefs, and give marine park managers the evidence they need to protect them.

1. Assess the population size, seasonality, movements, and habitat use of hawksbill and green turtles in the Nusa Penida Marine Protected Area, using long-term, individual-based sighting records.
2. Maintain a photo-identification catalog that combines our own surveys with citizen-science contributions, for sustained, non-invasive monitoring.
3. Identify the environmental conditions that shape where and when turtles are found across the MPA.
4. Extend the survey area to Karangasem Regency in East Bali to test how connected the turtle populations are beyond the MPA.
5. Develop a repeatable method that can be rolled out to Komodo National Park and the Derawan Islands, where MMF already works on manta rays.
6. Engage divers, snorkelers, and local communities in turtle photo-identification, building awareness and stewardship along the way.

Nusa Penida MPA, Bali is our longest-running site and the base for MMF’s Indonesian team. Turtle sightings have been recorded here since 2016, alongside our manta ray monitoring, with dedicated turtle surveys from 2022. The MPA sits in the Indonesian Throughflow, where warm Pacific water pushes into the Indian Ocean, and its shallow coral reefs draw large numbers of visiting divers, which makes it an ideal place for citizen science.

Karangasem Regency, East Bali was added in 2025 to look at hawksbill turtles outside the MPA and to build a citizen-science network with the dive community there.

Komodo National Park and the Derawan Islands MPA in East Kalimantan are the next steps. At Derawan, turtle monitoring already runs within our wider marine protected area program, alongside shark and ray surveys; the archipelago is famous for its nesting beaches and supports one of Indonesia’s largest turtle aggregations. At Komodo, turtle surveys will be integrated into our seasonal manta ray monitoring once the Nusa Penida method is fully established.

Nusa Penida hosts one of the longest in-water studies of hawksbill turtles anywhere in Indonesia. Between 2016 and 2024, our team completed nearly 1,800 surveys at 21 sites and recorded more than 1,200 hawksbill encounters, identifying close to 300 individual turtles. In 2025 alone we identified over 200 sea turtles at Nusa Penida, and a further 255 in the Derawan Islands.

Most Nusa Penida hawksbills are remarkably faithful to a single stretch of reef: around 85% of identified turtles were only ever seen in one region of the MPA, and many have been resighted across several years, with the longest record spanning more than seven years. The north and east coasts of Nusa Penida hold the most turtles. Turtles were more likely to be encountered when currents were running and less likely in rough seas.

These findings are being written up for peer-reviewed publication and have already been shared with the MPA management authority. They show that the reefs of Nusa Penida are important developmental and foraging habitat for hawksbill turtles, and that individual turtles depend on specific sites for years at a time, which is exactly the kind of information managers need when deciding where to focus protection and how to manage tourism.