The State of Sea Turtles in the East and Central Pacific Ocean
This regional article is part of “An Atlas of Global Sea Turtle Status”. See the full atlas here.
The East and Central Pacific is a vast and dynamic region spanning roughly from latitudes 35°N to 45°S. Bounded on the east by the Americas and stretching westward across a mosaic of islands, nations, and territories, this region hosts countless vital sea turtle habitats. Oceanographically, it is defined by powerful and variable forces—crisscrossing currents, strong upwellings, and dramatic shifts driven by El Niño–Southern Oscillation events. These dynamic conditions make the region uniquely challenging and highly variable for sea turtles, and over geologic time, it has been both the first region from which sea turtles disappear and the last to be recolonized. In response, sea turtles here exhibit adaptations that set them apart from their counterparts in other regions: East Pacific leatherbacks are smaller, lay fewer eggs, and take longer to return to nest; East Pacific hawksbills rely on mangrove estuaries throughout their lives and remain elusive; East Pacific green turtles are more carnivorous and differ in appearance from those of other regional management units (RMUs); and Hawaiian hawksbills and greens are functionally endemic.
The East and Central Pacific is home to four species of sea turtles and eight RMUs: green turtles (three RMUs), hawksbills (three), leatherbacks (one), and olive ridleys (one). The current status of these populations spans the full spectrum of conservation concern: from two strong and stable rookeries (East Pacific greens and East Pacific olive ridleys) to two of the most critically endangered on Earth (South Central Pacific greens and East Pacific leatherbacks).
An olive ridley arribada begins to pick up speed at sunset at Playa Escobilla in Oaxaca, Mexico, home to the world’s largest nesting aggregation. Over the ensuing five days of uninterrupted nesting activity, more than 300,000 females came ashore to nest. © Tui De Roy/Roving Tortoise Photos.
Research and Conservation
Sea turtle research and conservation in the East and Central Pacific began in the late 1960s and early 1970s. Some of the earliest efforts were in Pacific Mexico, launched in the late 1960s in response to steep population declines, and several remain active today. Thanks to legal protections, habitat preservation, and Mexico’s 1990 ban on commercial harvest, the green turtle population nesting in Pacific Mexico (part of the East Pacific green turtle RMU) has nearly quadrupled since the 1970s and is nearing full recovery. Green turtles from this RMU also appear healthy in the Galápagos Islands, Ecuador, where research and conservation efforts began in the 1970s. Interestingly, the once mysterious “Galápagos yellow turtle,” suspected by Archie Carr and other early researchers to be of West Pacific origin, has since been confirmed by genetic studies to be a migrant from the South Central Pacific green turtle RMU.
East Pacific olive ridleys, once harvested industrially along Mexico’s Pacific coast, have also rebounded, thanks to Mexico’s long-term conservation efforts, as well as those in Costa Rica and Nicaragua that began in the 1980s and 1990s. This RMU is known for its arribadas—mass nesting events—most notably at Escobilla Beach in Oaxaca, Mexico, site of the world’s largest arribada nesting phenomenon. Other arribada sites include Nancite and Ostional in Costa Rica, and La Flor and Río Escalante Chacocente in Nicaragua, with solitary nesting also common at many locations from Mexico to Peru.
Sea turtle research and conservation work in the Central Pacific also began in the late 1960s and early 1970s. Early efforts focused on documenting sea turtle distribution, abundance, and threats, often in very remote areas. Harold Hirth’s surveys in French Polynesia and subsequent recommendations led to protective legislation in 1971 that remains in place. For the North Central Pacific RMU, which nests entirely in Hawaii, fewer than 150 green turtles nested annually during initial surveys in 1973. Statewide protections were secured in 1974, bolstered by the addition of sea turtles to the U.S. Endangered Species Act in 1978. Since then, consistent monitoring has tracked steady population growth. However, this RMU is considered high risk, low threat, and its threat score increased from the 2011 Conservation Priorities Portfolio (CPP) assessment.
In recent decades, conservation programs have proliferated throughout the region, especially in the East Pacific, where several regional networks now coordinate activities. One prominent network is the Eastern Pacific Hawksbill Initiative (ICAPO). Begun in 2008 in response to the Marine Turtle Specialist Group’s Burning Issues list of global conservation priorities, ICAPO rediscovered East Pacific hawksbills, which were thought to be regionally extirpated. Today, more than 6 major and 40 minor hawksbill nesting sites have been identified in Mexico, El Salvador, Nicaragua, Panama, and Ecuador. In El Salvador alone, the nonprofit ProCosta has safeguarded more than 4,000 hawksbill nests. Similarly, the Eastern Pacific Leatherback Conservation Network (Laúd OPO), active since 2012, coordinates conservation across several countries, and its members are currently implementing a 10-year action plan to recover this high risk, high threat RMU.
In the Central Pacific, the Secretariat of the Pacific Regional Environment Programme (SPREP), an intergovernmental body founded in 1993, coordinates sea turtle conservation across the Pacific Island region. SPREP has supported efforts in 15 countries and territories, including American Samoa, Fiji, Tonga, the Cook Islands, Kiribati, and French Polynesia, partnering with local communities and nongovernmental organizations.
Overall, conservation efforts at multiple scales have contributed to the understanding and protection of sea turtles in the East and Central Pacific. Often overlooked, small nonprofits and community volunteers are the backbone of these efforts, working at the front lines. Notable long-term programs include the following:
Hawaii, U.S.A. (1973–present): After decades of overharvesting of Hawaiian green turtles (known locally as honu), state and federal protections helped drive a steady population recovery, supported by organizations, native communities, students, volunteers, and government agencies.
Michoacán, Mexico (1978–present): Based principally in the communities of Colola and Maruata, the grassroots organization Capital Mundial de la Tortuga Negra, in collaboration with the University of Michoacán–San Nicolás Hidalgo has achieved significant increases in green turtle nesting, curtailed hunting and egg collection, and won key habitat protections.
Oaxaca, Mexico (1980s–present): Tens of thousands of East Pacific olive ridleys were slaughtered annually in Oaxaca for local and export markets in turtle leather, oil, eggs, and meat. Mexico banned turtle harvesting nationwide in 1990, and the slaughterhouse was closed and replaced by the Mexican Sea Turtle Center, which is still active today. This RMU has since experienced an astounding recovery (learn more at “Living Legends,” Georgita Ruiz).
Guanacaste, Costa Rica (1990s–present): Years of research and advocacy led to the creation of the Las Baulas de Guanacaste National Marine Park, protecting what was once one of the most important nesting sites for East Pacific leatherbacks. Monitoring and protection have been under way for decades, led by Costa Rican government officials from the Sistema Nacional de Áreas de Conservación and The Leatherback Trust.
Baja California, Mexico (1999–present): Founded by local fishers, scientists, and conservationists, Grupo Tortuguero de las Californias has grown into a network of dozens of communities working to recover sea turtles through community-based monitoring, education, and bycatch reduction. What began as a grassroots movement in one village is now one of the region’s most enduring and influential sea turtle conservation efforts.
On a beach not frequented by tourists in Maui, Hawaii, hundreds of green turtles haul out at dusk to sleep. © Tui De Roy/Roving Tortoise Photos
Progress in Addressing Threats
Sea turtle conservation in the East and Central Pacific has seen mixed results, with RMUs ranging widely in status, even within species and geographies. Only three of the region’s eight RMUs—East Pacific hawksbills, East Pacific leatherbacks, and South Central Pacific greens—are considered to be under high threat overall. Five RMUs are facing high risk, of which four are in the Central Pacific, highlighting the region’s unique vulnerabilities.
Two RMUs—East Pacific leatherbacks and South Central Pacific greens—fall into the high risk, high threat category, making them among the most imperiled sea turtle populations globally. East Pacific leatherbacks are a well-known case. Decades of conservation efforts by governments, nonprofits, and communities in Mexico and Costa Rica, in particular, have failed to reverse the trend at key nesting sites, and population numbers today are perilously low. Thankfully, the population has shown encouraging signs of stabilizing since 2010, and improved international coordination under the Laúd OPO network provides reason for hope.
The South Central Pacific green turtle RMU is the only high risk, high threat green turtle RMU in the world, and its status has declined since 2011. Significant data gaps remain because of its remote rookeries and limited monitoring, but known threats, including bycatch, take, and climate change, combine to make this small population highly threatened.
Conversely, the North Central Pacific green turtle RMU (nesting in Hawaii) has recovered significantly since the 1970s and has low threats, but for a variety of factors, it remains at high risk. Hawksbill RMUs in the region show mixed trends. The East Pacific and South Central Pacific RMUs have improved since 2011, with reductions in threats and growing conservation capacity. The North Central Pacific hawksbill RMU, though under less threat, remains at high risk because of its low abundance and limited nesting sites. Encouragingly, both East Pacific green and olive ridley RMUs are currently considered low risk, low threat.
Bycatch and climate change are the region’s greatest overall threats. Bycatch is most severe in the East Pacific because of intense coastal fishing, which is especially problematic for East Pacific leatherbacks. Ongoing efforts to reduce bycatch range from activities that help small-scale fishers use turtle-friendly practices to regional policy efforts led by the Inter-American Convention for the Protection and Conservation of Sea Turtles and the Inter-American Tropical Tuna Commission.
Bycatch is a major threat to just one RMU in the Central Pacific, South Central Pacific green turtles, which are known to be caught in significant numbers by longline and net fisheries in American Samoa, Fiji, and the Cook Islands. Regulations in the Cook Islands since 2008 have sought to reduce the number of turtles caught in longlines, but their effectiveness is unclear.
Climate change poses a major threat to at least four RMUs through elevated beach temperatures that can reduce hatchling production and alter natural sex ratios, as well as rising sea levels that put nesting areas at risk of inundation, especially in low-lying islands of the Pacific. This threat is particularly concerning for RMUs with few nesting sites, a factor that already puts them at higher risk. Warming seas also cause coral bleaching and impacts to seagrass habitats. This threat is of particular concern in the Central Pacific, where it could disrupt critical foraging habitats.
Illegal harvesting of egg and adults remains a concern in parts of Central America, mainly affecting East Pacific greens and hawksbills. East Pacific olive ridley eggs are also taken, but the impacts appear less significant. A rare legal exception is Ostional, Costa Rica, where a regulated, community-based harvest permits the extraction of “doomed eggs” (eggs likely to be destroyed by subsequent nesters) during the early days of arribada nesting. The program has been the source of controversy, with critics saying that it validates egg consumption and provides a potential cover for the illegal egg trade. However, if managed collaboratively, paired with ecotourism, and legally enforced, the program can provide sustainable income without significant impacts on the turtle population.
Take of adult turtles is also a major concern for South Central Pacific green turtles, particularly given the population’s small size. At Scilly Atoll in French Polynesia, the RMU’s largest rookery (thought to have fewer than 400 nesters annually), residents are permitted to take up to 10 adults per year. Low levels of take elsewhere across the RMU’s range collectively threaten this vulnerable population.
Across the region, hundreds of organizations and communities contribute to turtle conservation. From local nongovernmental organizations to the Pacific-wide efforts of NOAA (National Oceanic and Atmospheric Administration) Fisheries, much of the work is driven by frontline action from small nonprofits and community members. Together, these efforts have laid the foundation for recovery across much of the region. Nevertheless, continued investment, collaboration, and innovation will be essential to turn the tide for the region’s most imperiled populations.
Status of Regional Management Units in the East and Central Pacific Ocean
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.