The State of Sea Turtles in the West Pacific Ocean
This regional article is part of “An Atlas of Global Sea Turtle Status”. See the full atlas here.
West Pacific sea turtles inhabit nearly one-third of the Earth’s surface, with reproductive sites spread out from Japan to Australia, and in nearly every nation in between. Three West Pacific RMUs in particular—one leatherback and two loggerhead—undertake some of the longest migrations in the animal kingdom, between nesting beaches in the West Pacific and foraging areas in the Eastern Pacific. Such sweeping distributions are what truly set West Pacific turtles apart from their counterparts in other regions.
Five sea turtle species—loggerheads (two RMUs), greens (two), leatherbacks (one), hawksbills (two), and olive ridleys (one)—make up the region’s eight RMUs. A sixth species, the flatback, is also present in the West Pacific, though it has no assigned RMUs and was not assessed by the CPP (see “The Flatback Turtle”). West Pacific turtles vary in status, though overall they face higher levels of risk and threat than in any other region. Three populations are classified as high risk and high threat. Bycatch, climate change, pollution, and illegal harvesting are the greatest threats, and those threats are compounded by local vulnerabilities at nesting sites. The West Pacific is at a critical juncture for sea turtle conservation; it is home to some of the most imperiled populations, and critical research and conservation needs. What happens here in the coming years will play a pivotal role in shaping the future of the region.
A loggerhead turtle rests on the seafloor in Ningaloo Reef, Western Australia. The West Pacific’s two loggerhead RMUs span the Pacific Ocean. © Lewis Burnett/Ocean Image Bank
Research and Conservation
The West Pacific region is home to some of the longest-running sea turtle conservation efforts in the world. In response to the overexploitation of green turtles, Japan’s Ministry of Agriculture and Commerce established one of the world’s first sea turtle head-start projects in 1910 on Chichijima Island, which is part of the Ogasawara Island group. The project was taken over by the Ogasawara Marine Center in 1982 and continues today, protecting one of the most important green turtle rookeries in the West Central Pacific green turtle RMU. Other Japanese initiatives followed in the 1950s and 1960s as public and scientific concern grew. North Pacific loggerheads nest exclusively in Japan, with the largest population on Yakushima Island. Consistent monitoring and protection began in the late 1970s, making this RMU one of the best-studied loggerhead populations on Earth.
Japan’s loggerheads migrate across the Pacific to feed, a fact that was discovered when a loggerhead turtle named Adelita was tracked from Baja California, Mexico, to Japan in 1996, the first transoceanic sea turtle migration to be satellite tracked. These connections are now well established, and researchers and conservationists in Japan and Mexico have been collaborating ever since.
To the south, research and conservation efforts focusing on leatherback turtles in the West Pacific began in Terengganu, Malaysia, as early as the 1950s. At the time, Malaysia’s coast was believed to host the largest leatherback nesting rookery in the world, with an estimated 2,000 females visiting annually. However, intensive egg harvesting (up to 99 percent), poor hatchery practices, and the expansion of coastal fisheries triggered a precipitous decline that resulted in the population being declared functionally extinct by 2010.
Fortunately, other West Pacific leatherback nesting rookeries, belonging to the same RMU have persisted, primarily in West Papua, Indonesia, and in Papua New Guinea and the Solomon Islands. Conservation efforts led by WWF, the National Oceanic and Atmospheric Administration (NOAA), The Nature Conservancy, the University of Papua, and others have worked to protect these nesting sites. Nevertheless, high levels of adult and egg harvesting remain one of the greatest challenges facing West Pacific leatherbacks, including a long-practiced traditional hunt in Indonesia’s Kei Islands. Satellite tagging by NOAA and other entities has greatly expanded the understanding of leatherback movements at sea, helping to inform strategies to reduce bycatch, one of the RMU’s most significant threats.
In Australia, long-term loggerhead and green turtle research began in 1968, when Dr. Colin Limpus initiated work at places such as Mon Repos and Wreck Rock in Queensland. These programs, now led by the Queensland Parks and Wildlife Service and the University of Queensland, have provided unprecedented insights into the links between foraging grounds and nesting sites, and have also helped monitor population trends for multiple turtle species found in eastern Australia and on the Great Barrier Reef. Significant research and conservation have also been done to understand and protect the flatback turtle throughout its range (see “The Flatback Turtle”).
Across the West Pacific, a robust network of conservation initiatives spans nearly all of the region’s critical turtle habitats. Notable long-term programs include the following:
Japan (1910–present): Ogasawara’s early green turtle head-start program (established 1910) and Yakushima’s intensive loggerhead research (1973) have made Japan a global leader in sea turtle conservation. The Sea Turtle Association of Japan (1990) coordinates nationwide efforts and hosts annual meetings for researchers and practitioners.
Queensland, Australia (1968–present): Long-term research on loggerheads, greens, and flatbacks, spearheaded by Dr. Colin Limpus, has provided unprecedented insights into the links between foraging and reproduction in sea turtles.
Golfo de Ulloa, Mexico (1990s–present): Community-led conservation efforts by Grupo Tortuguero de las Californias have identified a hotspot for Japanese loggerhead foraging and have worked to reduce bycatch threats there with support from Mexico’s Ministry of Environment and Natural Resources (SEMARNAT).
Raine Island, Australia (1993–present): The world’s largest green turtle rookery is protected through a partnership between government, industry, nonprofits, and the Wuthathi and Meriam Nation Traditional Owners. The program focuses on nest protection, habitat restoration, and climate adaptation.
West Papua, Indonesia (2000s–present): The most important nesting areas for leatherbacks in the West Pacific lie on the Bird’s Head Peninsula, where a collaboration among local communities, international nongovernmental organizations, NOAA, and university partners focuses on beach protection, bycatch reduction, community outreach, and scientific research.
A boy poses with a leatherback hatchling in the Bird’s Head Peninsula, West Papua, Indonesia. West Pacific leatherbacks are among the world’s most threatened RMUs. © Juergen Freund/naturepl.com
Progress in Addressing Threats
Despite significant conservation progress, sea turtle populations in the West Pacific still face the highest combined risk and threat levels globally. Short- and long-term population declines have been recorded across five RMUs, and six RMUs show rookery vulnerability, where a few key sites host the majority of an RMU’s nesting activity. Pollution, climate change, bycatch, and direct take rank among the top threats.
South Pacific loggerheads, which nest mainly in Australia and New Caledonia, exemplify many of these challenges. In the 1970s, about 3,500 loggerheads nested annually on Queensland beaches; by the early 2000s, the number had fallen to around 500, primarily owing to fisheries bycatch. Like their North Pacific counterparts, these animals migrate across the Pacific, feeding in waters of Peru and Chile. Intensive efforts to reduce bycatch—including mandatory turtle excluder devices in Australian shrimp trawlers and collaborations with small-scale fishers in Peru—have helped stabilize the population’s short-term trend. However, South Pacific loggerheads remain vulnerable because of their small population, low genetic diversity, and ongoing exposure to bycatch, pollution, and climate stressors.
North Pacific loggerheads, which nest in Japan and migrate across the Pacific to Mexico, have also faced short-term declines, with fisheries bycatch as a persistent threat. Local and transoceanic efforts to reduce bycatch have led to notable successes in Japan’s pound net fishery, the Hawaiian longline fishery, and Baja California’s coastal gillnet fisheries. Yet concerns about bycatch rates in Baja’s Gulf of Ulloa and Japan’s pound net fisheries remain.
Leatherback turtles in the West Pacific have suffered even steeper declines. The extinction of the Malaysian leatherback rookery serves as a stark warning. However, surviving rookeries in Papua, Indonesia (the RMU’s most abundant); Papua New Guinea; and the Solomon Islands continue to face threats from egg harvesting, adult take, and fisheries bycatch. As a result, the West Pacific leatherback RMU is the most imperiled leatherback population globally, with a dangerously high combined risk and threat score.
Meanwhile, Raine Island’s green turtles—despite their large numbers—face looming climate challenges. Erosion, inundation, and rising sand temperatures threaten nesting success, with dangerously skewed hatchling sex ratios and reduced hatchling production already observed. These Southwest Pacific green turtles also migrate to New Caledonia, where important but less well-studied rookeries, part of the same RMU, are found on remote uninhabited islands that are difficult to access. Traditional consumption of sea turtles is still practiced by New Caledonia’s Kanak people, for whom sea turtles are sacred. In 2021, eight Kanak tribes came together to create a sustainable management plan to protect sea turtles from overexploitation.
The West Central Pacific green turtle RMU, spanning from Papua New Guinea to Micronesia, benefits from a range of conservation measures, including habitat protection and community-led monitoring programs. But this population, while relatively stable, still faces pressure from illegal harvest and a lack of knowledge about impacts from other threats.
The region’s two hawksbill RMUs are small, with relatively few nesting sites, putting them at relatively high risk. The West Central Pacific population nests primarily in Palau, and there are significant gaps in our knowledge about its overall status, such as the population’s trend and the impact of threats. The Southwest Pacific hawksbill population, centered around northeast Australia, has declined significantly over the long term, and significant threats from climate change and direct take persist. However, conservation efforts have gained ground, with strengthened protections for key nesting and foraging areas and improved understanding of turtle movements through satellite tracking. Continued progress hinges on maintaining habitat protections, reducing bycatch, and enhancing international cooperation across the region.
West Pacific olive ridleys are a low-risk population, largely owing to their numerous and widely dispersed nesting sites across the region. However, the population has undergone a long-term decline, which only recently was stabilized by significant conservation efforts. One such effort, active since 2001, is led by the Tiwi Islands Marine Rangers, the first indigenous marine ranger program in Australia’s Northern Territory. The rangers protect sea turtles on and around the Tiwi Islands, including a sizable olive ridley nesting rookery belonging to the West Pacific RMU.
Plastic pollution, as well as discarded fishing gear and ghost nets in certain areas, such as the Gulf of Carpentaria, are escalating concerns throughout the region. And toxic runoff from shipping waste and bilge effluent, agriculture, and sewage has led to increasing levels of chemical contaminants found in turtle tissues. The Arafura Sea and Gulf of Carpentaria are also hotspots for illegal, unreported, and unregulated fishing.
All told, West Pacific sea turtles embody both remarkable resilience and continuing vulnerability. Decades of research, community action, and conservation investment have yielded important gains, but the future of these animals and their critical habitats will depend on sustained and coordinated efforts across this expansive geography.
See the “Atlas User Guide” for definitions and tips for interpreting these figures. Data citations can be downloaded here.
This article originally appeared in SWOT Report, vol. 20 (2025). Download this entire article as a PDF.