Indonesia · Since 2021

Indonesia Sea Turtle Project

Long-term, non-invasive photo-identification and size measurements of hawksbill and green turtles in Bali, East Kalimantan, and Komodo National Park.

308individual turtles identified in Komodo National Park, 2016 to 2026

374turtles identified in Nusa Penida and East Bali, 2014 to 2026

344turtles identified in the Derawan Islands, 2017 to 2026

Marine turtles are threatened with extinction. In Indonesia, we regularly encounter both hawksbill and green turtles, and we are cataloging them one sighting at a time.

Indonesia is home to six of the world’s seven sea turtle species, and its reefs and seagrass beds at the heart of the Coral Triangle are critical foraging grounds for many of them. Hawksbill turtles (Eretmochelys imbricata), Critically Endangered worldwide, and green turtles (Chelonia mydas), still recovering from decades of overexploitation, are the species divers most often meet on Indonesian reefs. Both continue to face egg poaching, illegal harvesting, fisheries entanglement, plastic ingestion, and boat strikes.

Yet most sea turtle research in Indonesia has focused on nesting beaches. Nesting counts tell us how many females come ashore each season, but they reveal little about juveniles, males, or the adults that spend most of their lives in the water. In-water surveys remain rare across the country, so we still know very little about how many turtles live on Indonesian reefs, how long they stay, how fast they grow, or how they are affected by the growing number of boats and divers around them.

Our project helps fill that gap. Working with SCUBA divers, snorkelers, and underwater photographers, we identify individual turtles from the unique pattern of scales on their faces, so no handling or tagging is needed. We also measure turtles in the water, allowing us to track their growth and work out which life stages use each site. Every sighting is added to the global Internet of Turtles database, where computer-vision matching helps us recognize turtles we have met before and follow individuals over years.

Objectives

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

Assess the population size, seasonality, movements, and habitat use of hawksbill and green turtles using long-term, individual-based sighting records.
Maintain a photo-identification catalog that combines our own surveys with citizen-science contributions for sustained, non-invasive monitoring.
Identify the environmental conditions that shape where and when turtles are found at our key sites.
Extend our surveys in Bali to the Karangasem Regency in East Bali to test how connected the turtle populations are beyond the Nusa Penida MPA.
Engage divers, snorkelers, and local communities in turtle photo-identification, building awareness and stewardship along the way.

A hawksbill turtle swims over a coral reef in Indonesia

What we've done

Collected in-water turtle photo-identification data across our key sites, with the majority of IDs collected being hawksbill turtles in the Nusa Penida MPA and Komodo National Park, and green turtles in the Derawan Islands MPA.
Measured sea turtles using the non-invasive laser photogrammetry method to distinguish sea turtle maturity and sex.
Initiated sea turtle citizen science data collection in East Bali, where olive ridley turtles have been spotted.

What's next

Publish our long-term hawksbill turtle population demographics and dynamics study that was conducted in the Nusa Penida MPA.
Expand our sea turtle surveys to West Nusa Tenggara.

Support our sea turtle research in Indonesia

Your gift funds the dive surveys, the photo-identification catalog, and the citizen-science briefings that let divers add their own turtle sightings.

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Our work on sea turtles in Indonesia

Nusa Penida: where hawksbill turtles thrive

We have recorded turtle sightings in the Nusa Penida MPA since 2016 and began dedicated turtle surveys in 2022. We have now identified more than 300 individual hawksbill turtles, ranging from juveniles to adults, and some have been resighted over as many as seven years. Turtles of every life stage use the MPA, and many stay for years, which makes it critical habitat for this Critically Endangered species.

A hawksbill turtle swims head-on toward the camera over a coral reef

East Bali: extending the network

East Bali is one of Bali’s most popular diving hubs, where turtles are a regular sight among divers. We began surveys here in 2025 to understand how hawksbill turtles use reefs outside the Nusa Penida MPA. We are also building a citizen science network with the local dive community, turning everyday dives into valuable data.

A hawksbill turtle swims low over a coral reef

Komodo National Park: turtles on a busy reef

Komodo National Park is best known for its dragons and manta rays, but its reefs are also important foraging grounds for hawksbill and green turtles. As one of Indonesia’s busiest dive destinations, it offers a rare opportunity to learn about turtles at a site under heavy tourism pressure. Since 2012, we have worked with partner dive centers in Labuan Bajo to photograph and identify turtles across the park, and have so far identified over 300 individuals.

A green turtle rests among plate corals in Komodo National Park

Derawan Islands MPA: green turtle haven

The Derawan archipelago is famous for its nesting beaches and supports one of Indonesia’s largest turtle aggregations. We have identified more than 340 individual green and hawksbill turtles across the islands. Although turtles are iconic in the region, they still face serious human threats, particularly boat strikes.