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Status, trends and conservation of global sea turtle populations

Nature Reviews Biodiversity volume 1, pages 119–133 (2025)Cite this article

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Abstract

Sea turtles experienced myriad human impacts during the twentieth century that caused extreme mortality across all seven species. Extensive conservation efforts have been undertaken to protect sea turtles and reverse the major declines seen in many of their populations. In this Review we assess the status and trends of global sea turtle populations and identify conservation interventions that have been linked to population recoveries. Some threats, such as the direct harvest of turtles, have abated, but threats posed by climate change and loss of nesting habitat continue to escalate. Both the International Union for the Conservation of Nature (IUCN) Red List assessments and an analysis of sea turtle abundance time series have revealed that, in general, sea turtle populations are rebounding worldwide, with nest numbers increasing at many nesting sites. However, certain populations are still declining dramatically, such as leatherback turtle populations in the Pacific Ocean and Caribbean Sea. Key unresolved questions include whether sea turtles can adapt to climate change, the magnitude of climate warming’s impact on adult sex ratios, and the effect of growing threats such as increasing plastic pollution. Despite some conservation successes, cautious optimism is advised when considering the future of sea turtles in a rapidly changing world.

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Fig. 1: Regional management units and conservation status of sea turtles.
Fig. 2: Threats to sea turtles.
Fig. 3: Assessing trends in turtle numbers.
Fig. 4: Trends in sea turtle abundance at focal sites and integrated across RMUs.
Fig. 5: Conservation interventions to help populations to recover.

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References

  1. Jackson, J. B. C. et al. Historical overfishing and the recent collapse of coastal ecosystems. Science 29, 629–638 (2001).

    Google Scholar 

  2. Bjorndal, K. A. & Jackson, J. B. in The Biology of Sea Turtles Vol. 2 (eds Lutz, P. L., Musick, J. A. & Wyneken, J.) 259–273 (CRC Press, 2002).

  3. Chan, E. H. Marine turtles in Malaysia: on the verge of extinction ? Aquat. Ecosyst. Health Manag. 9, 175–184 (2006).

    Google Scholar 

  4. Bevan, E. et al. Estimating the historic size and current status of the Kemp’s ridley sea turtle (Lepidochelys kempii) population. Ecosphere 7, e01244 (2016).

    Google Scholar 

  5. Duarte, C. M. et al. Rebuilding marine life. Nature 580, 39–51 (2020).

    CAS  Google Scholar 

  6. Convention on Biological Diversity. Kunming-Montreal Global Biodiversity Framework Decision CBD/COP/DEC/15/4. United Nations Environment Programme https://www.cbd.int/doc/decisions/cop-15/cop-15-dec-04-en.pdf (2022).

  7. Gilbert, N. Nations forge historic deal to save species: what’s in it and what’s missing. Nature 19, https://doi.org/10.1038/d41586-022-04503-9 (2022).

  8. Fuentes, M. M. P. B. et al. Key issues in assessing threats to sea turtles: knowledge gaps and future directions. Endangered Spec. Res. 52, 303–341 (2023).

    Google Scholar 

  9. Wallace, B. P. et al. Marine Turtle Regional Management Units 2.0: an updated framework for conservation and research of wide-ranging megafauna species. Endangered Spec. Res. 52, 209–223 (2023).

    Google Scholar 

  10. Carreras, C. et al. Sporadic nesting reveals long distance colonization in the philopatric loggerhead sea turtle (Caretta caretta). Sci. Rep. 8, 1435 (2018).

    Google Scholar 

  11. Shimada, T. et al. Fidelity to foraging sites after long migrations. J. Anim. Ecol. 89, 1008–1016 (2020).

    Google Scholar 

  12. Benson, S. R. et al. Large‐scale movements and high‐use areas of western Pacific leatherback turtles, Dermochelys coriacea. Ecosphere 2, 1–27 (2011).

    Google Scholar 

  13. Fossette, S. et al. Pan-Atlantic analysis of the overlap of a highly migratory species, the leatherback turtle, with pelagic longline fisheries. Proc. R. Soc. Lond. B 281, 20133065 (2014).

    CAS  Google Scholar 

  14. Hays, G. C., Cerritelli, G., Esteban, N., Rattray, A. & Luschi, P. Open ocean reorientation and challenges of island finding by sea turtles during long-distance migration. Curr. Biol. 30, 3236–3242 (2020).

    CAS  Google Scholar 

  15. Le Gall, J.-Y. & Hughes, G. R. Migrations de la tortue vertes Chelonia mydas dans l’Ocean Indien Sud-Ouest observees a partir des marquages sur les sites de ponte Europa et Tromelin (1970–1980). Amphib. Reptil. 8, 272–282 (1987).

    Google Scholar 

  16. Hays, G. C., Adams, C. & Speakman, J. R. Reproductive investment by green turtles nesting on Ascension Island. Can. J. Zool. 71, 1098–1103 (1993).

    Google Scholar 

  17. Esteban, N. et al. A global review of green turtle diet: sea surface temperature as a potential driver of omnivory levels. Mar. Biol. 167, 183 (2020).

    Google Scholar 

  18. Bell, I. Algivory in hawksbill turtles: Eretmochelys imbricata food selection within a foraging area on the Northern Great Barrier Reef. Mar. Ecol. 34, 43–55 (2013).

    Google Scholar 

  19. Meylan, A. Spongivory in hawksbill turtles: a diet of glass. Science 239, 393–395 (1988).

    CAS  Google Scholar 

  20. Reynolds, K. S. et al. Diet of hawksbill turtles (Eretmochelys imbricata) in the Gulf of California, Mexico. Aquat. Conserv. Mar. Freshw. Ecosyst. 33, 917–925 (2023).

    Google Scholar 

  21. Hays, G. C., Doyle, T. K. & Houghton, J. D. R. A paradigm shift in the trophic importance of jellyfish? Trends Ecol. Evol. 11, 874–884 (2018).

    Google Scholar 

  22. Hatase, H., Omuta, K. & Tsukamoto, K. Bottom or midwater: alternative foraging behaviours in adult female loggerhead sea turtles. J. Zool. 273, 46–55 (2007).

    Google Scholar 

  23. Whiting, S. D., Long, J. L. & Coyne, M. Migration routes and foraging behaviour of olive ridley turtles Lepidochelys olivacea in northern Australia. Endangered Spec. Res. 3, 1–9 (2007).

    Google Scholar 

  24. Gredzens, C. & Shaver, D. J. Satellite tracking can inform population-level dispersal to foraging grounds of post-nesting Kemp’s ridley sea turtles. Front. Mar. Sci. 7, 559 (2020).

    Google Scholar 

  25. Butler, Z. P. et al. Predation of loggerhead sea turtle eggs across Georgia’s barrier islands. Glob. Ecol. Conserv. 2, e01139 (2020).

    Google Scholar 

  26. Stokes, H. J., Esteban, N. & Hays, G. C. Predation of sea turtle eggs by rats and crabs. Mar. Biol. 171, 17 (2024).

    Google Scholar 

  27. Aoki, D. M. et al. Forensic determination of shark species as predators and scavengers of sea turtles in Florida and Alabama, USA. Mar. Ecol. Prog. Ser. 703, 145–159 (2023).

    Google Scholar 

  28. Ortega-Ortiz, C. D. et al. Expanding information on the prey items and hunting tactics of the eastern tropical pacific killer whale (Orcinus orca) ecotype. Examines Mar. Biol. Oceanogr. 6, 000635 (2023).

    Google Scholar 

  29. Senko, J. F. et al. Global patterns of illegal marine turtle exploitation. Glob. Change Biol. 28, 6509–6523 (2022).

    CAS  Google Scholar 

  30. Miller, E. A. et al. The historical development of complex global trafficking networks for marine wildlife. Sci. Adv. 5, eaav5948 (2019).

    Google Scholar 

  31. Tapilatu, R. F. et al. Long-term decline of the western Pacific leatherback, Dermochelys coriacea: a globally important sea turtle population. Ecosphere 4, 1–15 (2013).

    Google Scholar 

  32. Tomillo, P. S., Saba, V. S., Piedra, R., Paladino, F. V. & Spotila, J. R. Effects of illegal harvest of eggs on the population decline of leatherback turtles in Las Baulas Marine National Park, Costa Rica. Conserv. Biol. 22, 1216–1224 (2008).

    Google Scholar 

  33. Sarti et al. Conservation and biology of the leatherback turtle in the Mexican Pacific. Chelonian Conserv. Biol. 6, 70–78 (2007).

    Google Scholar 

  34. Humber, F., Godley, B. J. & Broderick, A. C. So excellent a fishe: a global overview of legal marine turtle fisheries. Divers. Distrib. 20, 579–590 (2014).

    Google Scholar 

  35. Stringell, T. B. et al. Protecting the breeders: research informs legislative change in a marine turtle fishery. Biodivers. Conserv. 24, 1775–1796 (2015).

    Google Scholar 

  36. Donnelly, M. in Sea Turtle Research and Conservation (ed. Nahill, B.) 133–139 (Academic Press, 2021).

  37. Kirishnamoorthie, J., Hideaki, N., James, A., Hussien, M. & Juanita, J. Illegal tortoiseshell harvest of hawksbill turtles (Eretmochelys imbricata) in Southeast Asia: evidence from Baturua Reef, Semporna, Sabah, Malaysia. J. Sustain. Sci. Manag. 18, 54–67 (2023).

    Google Scholar 

  38. Wallace, B. P. et al. Impacts of fisheries bycatch on marine turtle populations worldwide: toward conservation and research priorities. Ecosphere 4, 1–49 (2013).

    Google Scholar 

  39. Peckham, S. H. et al. Small-scale fisheries bycatch jeopardizes endangered Pacific loggerhead turtles. PLoS ONE 2, e1041 (2007).

    Google Scholar 

  40. Hamelin, K. M., James, M. C., Ledwell, W., Huntington, J. & Martin, K. Incidental capture of leatherback sea turtles in fixed fishing gear off Atlantic Canada. Aquat. Conserv. 27, 631–642 (2017).

    Google Scholar 

  41. Dodge, K. L. et al. Disentanglement network data to characterize leatherback sea turtle Dermochelys coriacea bycatch in fixed gear fisheries. Endangered Spec. Res. 47, 155–170 (2022).

    Google Scholar 

  42. The Laúd OPO Network. Enhanced, coordinated conservation efforts required to avoid extinction of critically endangered Eastern Pacific leatherback turtles. Sci. Rep. 10, 4772 (2020).

    Google Scholar 

  43. Lewison, R. L., Freeman, S. A. & Crowder, L. B. Quantifying the effects of fisheries on threatened species: the impact of pelagic longlines on loggerhead and leatherback sea turtles. Ecol. Lett. 7, 221–231 (2004).

    Google Scholar 

  44. Schuyler, Q., Hardesty, B. D., Wilcox, C. & Townsend, K. Global analysis of anthropogenic debris ingestion by sea turtles. Conserv. Biol. 28, 129–139 (2013).

    Google Scholar 

  45. Senko, J. F. et al. Understanding individual and population-level effects of plastic pollution on marine megafauna. Endangered Spec. Res. 43, 234–252 (2020).

    Google Scholar 

  46. Mashkour, N. et al. Disease risk analysis in sea turtles: a baseline study to inform conservation efforts. PLoS ONE 15, e0230760 (2020).

    CAS  Google Scholar 

  47. Fuentes, M. M. P. B., Fish, M. R. & Maynard, J. A. Management strategies to mitigate the impacts of climate change on sea turtle’s terrestrial reproductive phase. Mitig. Adapt. Strat. Glob. Change 17, 51–63 (2012).

    Google Scholar 

  48. Patrício, A. R., Hawkes, L. A., Monsinjon, J. R., Godley, B. J. & Fuentes, M. M. P. B. Climate change and marine turtles: recent advances and future directions. Endangered Spec. Res. 44, 363–395 (2021).

    Google Scholar 

  49. Maurer, A. S. et al. Population viability of sea turtles in the context of global warming. BioScience 71, 790–804 (2021).

    Google Scholar 

  50. Hamann, M., Fuentes, M. M. P. B., Ban, N. C. & Mocellin, V. J. L. in The Biology of Sea Turtles (eds Wyneken, J., Lohmann, K. J. & Musick, J. A.) 353–358 (CRC Press, 2013).

  51. Santidrián Tomillo, P. & Spotila, J. R. Temperature‐dependent sex determination in sea turtles in the context of climate change: uncovering the adaptive significance. BioEssays 42, 2000146 (2020).

    Google Scholar 

  52. Laloë, J.-O., Schofield, G. & Hays, G. C. Climate warming and sea turtle sex ratios across the globe. Glob. Change Biol. 30, e17004 (2024).

    Google Scholar 

  53. Mazaris, A. D., Schofield, G., Gkazinou, C., Almpanidou, V. & Hays, G. C. Global sea turtle conservation successes. Sci. Adv. 3, e1600730 (2017).

    Google Scholar 

  54. Booth, D. T. Influence of incubation temperature on sea turtle hatchling quality. Integr. Zool. 12, 352–360 (2017).

    Google Scholar 

  55. Hays, G. C., Mazaris, A. D., Schofield, G. & Laloë, J.-O. Population viability at extreme sex-ratio skews produced by temperature-dependent sex determination. Proc. R. Soc. Lond. B 284, 20162576 (2017).

    Google Scholar 

  56. Laloë, J.-O., Cozens, J., Renom, B., Taxonera, A. & Hays, G. C. Climate change. and temperature-linked hatchling mortality at a globally important sea turtle nesting site. Glob. Change Biol. 23, 4922–4931 (2017).

    Google Scholar 

  57. Smithers, S. G. & Dawson, J. L. Beach reprofiling to improve reproductive output at the world’s largest remaining green turtle rookery: Raine Island, northern Great Barrier Reef. Ocean Coast. Manag. 231, 106385 (2023).

    Google Scholar 

  58. Varela, M. R. et al. Assessing climate change associated sea-level rise impacts on sea turtle nesting beaches using drones, photogrammetry and a novel GPS system. Glob. Change Biol. 25, 753–762 (2019).

    Google Scholar 

  59. Turkozan, O., Almpanidou, V., Yılmaz, C. & Mazaris, A. D. Extreme thermal conditions in sea turtle nests jeopardize reproductive output. Clim. Change 167, 30 (2021).

    Google Scholar 

  60. Hays, G. C., Chivers, W. J., Laloë, J. O., Sheppard, C. & Esteban, N. Impact of marine heatwaves for sea turtle nest temperatures. Biol. Lett. 17, 20210038 (2021).

    Google Scholar 

  61. Konsta, A. et al. Marine heatwaves threaten key foraging grounds of sea turtles in Southeast Asian Seas. Reg. Environ. Change 22, 97 (2022).

    Google Scholar 

  62. Poloczanska, E. S., Limpus, C. J. & Hays, G. C. Vulnerability of marine turtles to climate change. Adv. Mar. Biol. 56, 151–211 (2009).

    Google Scholar 

  63. Osland, M. J. et al. Tropicalization of temperate ecosystems in North America: the northward range expansion of tropical organisms in response to warming winter temperatures. Glob. Change Biol. 27, 3009–3034 (2021).

    Google Scholar 

  64. Fuentes, M. M. P. B., Meletis, Z. A., Wildermann, N. E. & Ware, M. Conservation interventions to reduce vessel strikes on sea turtles: a case study in Florida. Mar. Policy 128, 104471 (2021).

    Google Scholar 

  65. Foley, A. M. et al. Characterizing watercraft-related mortality of sea turtles in Florida. J. Wildl. Manag. 83, 1057–1072 (2019).

    Google Scholar 

  66. Womersley, F. C., Loveridge, A. & Sims, D. W. Shipping is on the rise: four steps to curb ‘ocean roadkill’. Nature 621, 34–38 (2023).

    CAS  Google Scholar 

  67. Kamrowski, R. L., Limpus, C., Moloney, J. & Hamann, M. Coastal light pollution and marine turtles: assessing the magnitude of the problem. Endangered Spec. Res. 19, 85–98 (2012).

    Google Scholar 

  68. Pereira, J. A., Martins, A. S., Seminoff, J. A. & de Azevedo Mazzuco, A. C. Long-term changes in body size of green turtles nesting on Trindade Island, Brazil: signs of recovery? Mar. Environ. Res. 186, 105930 (2023).

    CAS  Google Scholar 

  69. Nordberg, E. J. et al. An evaluation of nest predator impacts and the efficacy of plastic meshing on marine turtle nests on the western Cape York Peninsula, Australia. Biol. Conserv. 238, 108201 (2019).

    Google Scholar 

  70. Pakiding, F. et al. Community engagement: an integral component of a multifaceted conservation approach for the transboundary western Pacific leatherback. Front. Mar. Sci. 7, 549570 (2020).

    Google Scholar 

  71. Meylan, P. A., Hardy, R. F., Gray, J. A. & Meylan, A. B. A half-century of demographic changes in a green turtle (Chelonia mydas) foraging aggregation during an era of seagrass decline. Mar. Biol. 169, 74 (2022).

    CAS  Google Scholar 

  72. Esteban, N., Mortimer, J. A. & Hays, G. C. How numbers of nesting sea turtles can be over-estimated by nearly a factor of two. Proc. R. Soc. B 284, 20162581 (2017).

    Google Scholar 

  73. Hays, G. C., Mazaris, A. D. & Schofield, G. Inter-annual variability in breeding census data across species and regions. Mar. Biol. 169, 54 (2022).

    Google Scholar 

  74. Broderick, A. C., Godley, B. J. & Hays, G. C. Trophic status drives interannual variability in nesting numbers of marine turtles. Proc. R. Soc. Lond. B 268, 1481–1487 (2001).

    CAS  Google Scholar 

  75. Hays, G. C. et al. A pulse check for trends in sea turtle numbers across the globe. iScience 27, 109071 (2024).

    Google Scholar 

  76. Casale, P. et al. New methods to derive sea turtle nester abundance from nest counts: ground truthing and the bias of current approaches. Biol. Cons. 275, 109754 (2022).

    Google Scholar 

  77. Cuevas, E. et al. First spatial distribution analysis of male sea turtles in the southern Gulf of Mexico. Front. Mar. Sci. 7, 561846 (2020).

    Google Scholar 

  78. Casale, P., Freggi, D., Maffucci, F. & Hochscheid, S. Adult sex ratios of loggerhead sea turtles (Caretta caretta) in two Mediterranean foraging grounds. Sci. Mar. 78, 303–309 (2014).

    Google Scholar 

  79. Schofield, G., Katselidis, K. A., Lilley, M. K., Reina, R. D. & Hays, G. C. Detecting elusive aspects of wildlife ecology using drones: new insights on the mating dynamics and operational sex ratios of sea turtles. Funct. Ecol. 31, 2310–2319 (2017).

    Google Scholar 

  80. Hays, G. C., Laloë, J.-O., Lee, P. L. M. & Schofield, G. Evidence of adult male scarcity associated with female-skewed offspring sex ratios in sea turtles. Curr. Biol. 33, R1–R15 (2023).

    Google Scholar 

  81. Early-Capistrán, M. M. et al. Integrating local ecological knowledge, ecological monitoring, and computer simulation to evaluate conservation outcomes. Conserv. Lett. 15, e12921 (2022).

    Google Scholar 

  82. Schofield, G., Esteban, N., Katselidis, K. A. & Hays, G. C. Drones for research on sea turtles and other marine vertebrates — a review. Biol. Conser. 238, 108214 (2019).

    Google Scholar 

  83. Stokes, H. J., Mortimer, J. A., Laloë, J.-O., Hays, G. C. & Esteban, N. Synergistic use of UAV surveys, satellite tracking data, and mark–recapture to estimate abundance of elusive species. Ecosphere 14, e4444 (2023).

    Google Scholar 

  84. Dunbar, S. G. et al. HotSpotter: using a computer-driven photo-ID application identify sea turtles. J. Exp. Mar. Biol. Ecol. 535, 151490 (2021).

    Google Scholar 

  85. Hanna, M. E. Citizen-sourced sightings and underwater photography reveal novel insights about green sea turtle distribution and ecology in southern California. Front. Mar. Sci. 8, 671061 (2021).

    Google Scholar 

  86. Sellés-Ríos, B. et al. Warm beach, warmer turtles: using drone-mounted thermal infrared sensors to monitor sea turtle nesting activity. Front. Conserv. Sci. 3, 954791 (2022).

    Google Scholar 

  87. Dobbs, K. Marine turtles in the Great Barrier Reef world heritage area: a compendium of information and basis for the development of policies and strategies for the conservation of marine turtles. Great Barrier Reef Marine Park Authority https://elibrary.gbrmpa.gov.au/jspui/retrieve/be8152ba-0d19-41fe-8183-71b65e982828/Marine-turtles-GBRWHA-compendium.pdf (2001).

  88. Seminoff, J. A. et al. Status review of the green turtle (Chelonia mydas) under the endangered species act. NOAA https://repository.library.noaa.gov/view/noaa/4922 Technical Memorandum NOAA-NMFS-SWFSC-539 (2015).

  89. Seminoff, J. A. Green turtle Chelonia mydas: the IUCN red list of threatened species. IUCN https://www.iucnredlist.org/species/4615/247654386 (2023).

  90. Casale, P. & Tucker, A. D. Loggerhead turtle Caretta caretta: the IUCN red list of threatened species. IUCN https://www.iucnredlist.org/species/3897/119333622 (2017).

  91. Snover, M. L. & Heppell, S. S. Application of diffusion approximation for risk assessments of sea turtle populations. Ecol. Appl. 19, 774–785 (2009).

    Google Scholar 

  92. Van Houtan, K. S. & Halley, J. M. Long-term climate forcing in loggerhead sea turtle nesting. PLoS ONE 6, e19043 (2011).

    Google Scholar 

  93. Mazaris, A. D., Kornaraki, E., Matsinos, Y. G. & Margaritoulis, D. Modeling the effect of sea surface temperature on sea turtle nesting activities by investigating seasonal trends. Nat. Resour. Model. 17, 445–465 (2004).

    Google Scholar 

  94. Ceriani, S. A., Casale, P., Brost, M., Leone, E. H. & Witherington, B. E. Conservation implications of sea turtle nesting trends: elusive recovery of a globally important loggerhead population. Ecosphere 10, e02936 (2019).

    Google Scholar 

  95. Guidelines for using the IUCN Red List categories and criteria: version 16 IUCN https://www.iucnredlist.org/resources/redlistguidelines (2019).

  96. Mrosovsky, N. IUCN’s credibility critically endangered. Nature 389, 436 (1997).

    CAS  Google Scholar 

  97. Seminoff, J. A. & Shanker, K. Marine turtles and IUCN Red Listing: a review of the process, the pitfalls, and novel assessment approaches. J. Exp. Mar. Biol. Ecol. 356, 52–68 (2008).

    Google Scholar 

  98. Wallace, B. P., Tiwari, M. & Girondot, M. Leatherback turtle Dermochelys coriacea: the IUCN red list of threatened species. IUCN https://www.iucnredlist.org/species/6494/43526147 (2013).

  99. Bourjea, J. & Dalleau, M. Green turtle Chelonia mydas (Southwest Indian Ocean subpopulation). The IUCN Red List of Threatened Species IUCN https://www.iucnredlist.org/species/220970396/220970430 (2023).

  100. Pritchard, A. M. et al. Green turtle population recovery at Aldabra Atoll continues after 50 yr of protection. Endangered Spec. Res. 47, 205–215 (2022).

    Google Scholar 

  101. Weber, S. B. et al. Recovery of the South Atlantic’s largest green turtle nesting population. Biodivers. Conserv. 23, 3005–3018 (2014).

    Google Scholar 

  102. Chaloupka, M. Y. & Pilcher, N. J. Green turtle Chelonia mydas (Hawaiian subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/16285718/142098300 (2019).

  103. Broderick, A. & Patricio, A. Green turtle Chelonia mydas (South Atlantic subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/142121866/142086337 (2019).

  104. Broderick, A. C. et al. Green turtle Chelonia mydas (Mediterranean subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/4616/259027885 (2024).

  105. Restrepo, J., Webster, E. G., Ramos, I. & Valverde, R. A. Recent decline of green turtle Chelonia mydas nesting trend at Tortuguero, Costa Rica. Endangered Spec. Res. 51, 59–72 (2023).

    Google Scholar 

  106. Troëng, S. & Rankin, E. Long-term conservation efforts contribute to positive green turtle Chelonia mydas nesting trend at Tortuguero, Costa Rica. Biol. Conserv. 121, 111–116 (2005).

    Google Scholar 

  107. Hays, G. C. et al. Changes in mean body size in an expanding population of a threatened species. Proc. R. Soc. B 289, 20220696 (2022).

    Google Scholar 

  108. Willson, A. et al. Evaluating the long-term trend and management of a globally important loggerhead population nesting on Masirah Island, Sultanate of Oman. Front. Mar. Sci. 7, 666 (2020).

    Google Scholar 

  109. Casale, P. Loggerhead turtle Caretta caretta (Mediterranean subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/83644804/83646294 (2015).

  110. Casale, P. & Matsuzawa, Y. Loggerhead turtle Caretta caretta (North Pacific subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/83652278/83652322 (2015).

  111. Ceriani, S. A. & Meylan, A. B. Loggerhead turtle Caretta caretta (North West Atlantic subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/84131194/119339029 (2017).

  112. Casale, P. & Marcovaldi, M. Loggerhead turtle Caretta caretta (South West Atlantic subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/84191235/84191397 (2015).

  113. Casale, P. Loggerhead turtle Caretta caretta (North West Indian Ocean subpopulation: the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/84127873/84127992 (2015).

  114. Casale, P. Loggerhead turtle Caretta caretta (North East Indian Ocean subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/84126444/84126520 (2015).

  115. Limpus, C. & Casale, P. Loggerhead turtle Caretta caretta (South Pacific subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/84156809/84156890 (2015).

  116. Casale, P. & Marco, A. Loggerhead turtle Caretta caretta (North East Atlantic subpopulation): the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/83776383/83776554 (2015).

  117. Abreu-Grobois, A. & Plotkin, P. (IUCN SSC Marine Turtle Specialist Group). Olive ridley turtle Lepidochelys olivacea: the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/11534/3292503 (2008).

  118. Wibbels, T. & Bevan, E. Kemp’s ridley Lepidochelys kempii: the IUCN Red List of Threatened Species. IUCN https://www.iucnredlist.org/species/11533/155057916 (2019).

  119. Mohan, P. & Strobl, E. Tourism and marine crises: the impact of Sargassum invasion on Caribbean small island developing states. Ocean. Coast. Manag. 251, 107091 (2024).

    Google Scholar 

  120. Tiwari, M. An evaluation of the perceived effectiveness of international instruments for sea turtle conservation. J. Int. Wildl. Law Policy 5, 145–156 (2002).

    Google Scholar 

  121. Seminoff, J. A. et al. Loggerhead sea turtle abundance at an offshore foraging hotspot in the eastern Pacific Ocean: implications for at-sea conservation. Endangered Spec. Res. 24, 207–220 (2014).

    Google Scholar 

  122. Hays, G. C. et al. Translating marine animal tracking data into conservation policy and management. Trends Ecol. Evol. 34, 459–473 (2019).

    Google Scholar 

  123. Mortimer, J. A., Esteban, N., Guzman, A. N. & Hays, G. C. Estimates of sea turtle nesting populations in the south-western Indian Ocean indicate the importance of the Chagos Archipelago. Oryx 54, 332–343 (2020).

    Google Scholar 

  124. Bojórquez-Tapia, L. A. et al. A continual engagement framework to tackle wicked problems: curtailing loggerhead sea turtle fishing bycatch in Gulf of Ulloa, Mexico. Sustain. Sci. 12, 535–548 (2017).

    Google Scholar 

  125. Rife, A. N., Erisman, B., Sanchez, A. & Aburto‐Oropeza, O. When good intentions are not enough… Insights on networks of “paper park” marine protected areas. Conserv. Lett. 6, 200–212 (2013).

    Google Scholar 

  126. Hays, G. C. et al. A review of a decade of lessons from one of the world’s largest MPAs: conservation gains and key challenges. Mar. Biol. 167, 159 (2020).

    Google Scholar 

  127. Hays, G. C., Rattray, A. & Esteban, N. Addressing tagging location bias to assess space use by marine animals. J. Appl. Ecol. 57, 1981–1987 (2020).

    Google Scholar 

  128. Aridjis, H. Mexico proclaims total ban on harvest of turtles and eggs. Mar. Turt. Newsl. 50, 1–3 (1990).

    Google Scholar 

  129. Edwards, R. C., Godley, B. J. & Nuno, A. Exploring connections among the multiple outputs and outcomes emerging from 25 years of sea turtle conservation in Northern Cyprus. J. Nat. Conserv. 55, 125816 (2020).

    Google Scholar 

  130. Godley, B. J. et al. Reflections on sea turtle conservation. Oryx 54, 287–289 (2020).

    Google Scholar 

  131. Hancock, J. M., Furtado, S., Merino, S., Godley, B. J. & Nuno, A. Exploring drivers and deterrents of the illegal consumption and trade of marine turtle products in Cape Verde, and implications for conservation planning. Oryx 51, 428–436 (2017).

    Google Scholar 

  132. Thomas-Walters, L. et al. Challenges in the impact evaluation of behaviour change interventions: the case of sea turtle meat and eggs in São Tomé. People Nat. 2, 913–922 (2020).

    Google Scholar 

  133. Marcovaldi, M. A. & dei Marcovaldi, G. G. Marine turtles of Brazil: the history and structure of Projeto TAMAR-IBAMA. Biol. Conserv. 91, 35–41 (1999).

    Google Scholar 

  134. Lewison, R. L., Crowder, L. B. & Shaver, D. J. The impact of turtle excluder devices and fisheries closures on loggerhead and Kemp’s ridley strandings in the western Gulf of Mexico. Conserv. Biol. 17, 1089–1097 (2003).

    Google Scholar 

  135. Alkire, C. Decline in on-demand fishing gear costs with learning. Front. Mar. Sci. 9, 943552 (2022).

    Google Scholar 

  136. Ortiz-Alvarez, C. et al. Rapid assessments of leatherback small-scale fishery bycatch in internesting areas in the Eastern Pacific Ocean. Front. Mar. Sci. 6, 813 (2020).

    Google Scholar 

  137. Jenkins, L. D., Eayrs, S., Pol, M. V. & Thompson, K. R. Uptake of proven bycatch reduction fishing gear: perceived best practices and the role of affective change readiness. ICES J. Mar. Sci. 80, 437–445 (2023).

    Google Scholar 

  138. Evans, S. et al. Investigating the effectiveness of a well‐managed hatchery as a tool for hawksbill sea turtle (Eretmochelys imbricata) conservation. Conserv. Sci. Pract. 4, e12819 (2022).

    Google Scholar 

  139. Pritchard, P. C. H. The conservation of sea turtles: practices and problems. Am. Zool. 20, 609–617 (1980).

    Google Scholar 

  140. Bell, C. D. et al. Some of them came home: the Cayman Turtle Farm headstarting project for the green turtle Chelonia mydas. Oryx 39, 137–148 (2005).

    Google Scholar 

  141. Kanghae, H. et al. First successful head‐start program of leatherback sea turtles (Dermochelys coriacea) in Thailand and proposed dietary strategy. Zoo. Biol. 43, 110–122 (2024).

    CAS  Google Scholar 

  142. Hill, J. E., Paladino, F. V., Spotila, J. R. & Tomillo, P. S. Shading and watering as a tool to mitigate the impacts of climate change in sea turtle nests. PLoS ONE 10, e0129528 (2015).

    Google Scholar 

  143. Esteban, N. et al. Optimism for mitigation of climate warming impacts for sea turtles through nest shading and relocation. Sci. Rep. 8, 17625 (2018).

    Google Scholar 

  144. Saengsupavanich, C., Pranzini, E., Ariffin, E. H. & Yun, L. S. Jeopardizing the environment with beach nourishment. Sci. Total. Environ. 868, 161485 (2023).

    CAS  Google Scholar 

  145. Ernest, R. G. et al. Changes in loggerhead sea turtle nesting behavior on a nourished beach in southeast Florida. J. Coast. Res. https://doi.org/10.2112/JCOASTRES-D-23-00092.1 (2024).

  146. Shamblott, K. M., Reneker, J. L. & Kamel, S. J. The thermal impacts of beach nourishment across a regionally important loggerhead sea turtle (Caretta caretta) rookery. Ecosphere 12, e03396 (2021).

    Google Scholar 

  147. Shimada, T., Limpus, C. J., Jones, R. & Hamann, M. Aligning habitat use with management zoning to reduce vessel strike of sea turtles. Ocean. Coast. Manag. 142, 163–172 (2017).

    Google Scholar 

  148. Schofield, G. et al. Evidence-based marine protected area planning for a highly mobile endangered marine vertebrate. Biol. Conserv. 161, 101–109 (2013).

    Google Scholar 

  149. Frame, J. R. et al. Measuring of the effects of a sea turtle conservation education program on children’s knowledge and attitudes in Grenada, West Indies. Ocean. Coast. Manag. 211, 105752 (2021).

    Google Scholar 

  150. Mascovich, K. A., Larson, L. R. & Andrews, K. M. Talking turtles with tourists: evaluating the relative conservation impacts of different types of sea turtle education programs at Jekyll Island, GA, USA. J. Interpret. Res. 28, 95–120 (2023).

    Google Scholar 

  151. Hamann, M., Limpus, C., Hughes, G., Mortimer, J.A. & Pilcher, N. Assessment of the conservation status of leatherback turtles in the Indian Ocean and South-East Asia. IOSEA https://www.cms.int/iosea-turtles/sites/default/files/document/MT_IO4_DOC09_DC-tsunami_report_Part1_Intro-Australia.pdf (2006).

  152. Hays, G. C. & Hawkes, L. A. Satellite tracking sea turtles: opportunities and challenges to address key questions. Front. Mar. Sci. 5, 432 (2018).

    Google Scholar 

  153. Hazen, E. L. et al. A dynamic ocean management tool to reduce bycatch and support sustainable fisheries. Sci. Adv. 4, eaar3001 (2018).

    Google Scholar 

  154. Bowen, B. W., Conant, T. A. & Hopkins-Murphy, S. R. Where are they now? The Kemp’s Ridley Headstart Project. Cons. Biol. 8, 853–856 (1994).

    Google Scholar 

  155. Liles, M. J. et al. Connecting international priorities with human wellbeing in low-income regions: lessons from hawksbill turtle conservation in El Salvador. Local. Environ. 20, 1383–1404 (2015).

    Google Scholar 

  156. Senko, J. et al. People helping turtles, turtles helping people: understanding resident attitudes towards sea turtle conservation and opportunities for enhanced community participation in Bahia Magdalena, Mexico. Ocean. Coast. Manag. 54, 148–157 (2011).

    Google Scholar 

  157. Hays, G. C., Mazaris, A. D. & Schofield, G. Different male vs. female breeding periodicity helps mitigate offspring sex ratio skews in sea turtles. Front. Mar. Sci. 1, 43 (2014).

    Google Scholar 

  158. Laloë, J.-O. & Hays, G. C. Can a present-day thermal niche be preserved in a warming climate by a shift in phenology? A case study with sea turtles. R. Soc. Open. Sci. 10, 221002 (2023).

    Google Scholar 

  159. Fuentes, M. M. P. B. et al. Adaptation of sea turtles to climate warming: will phenological responses be sufficient to counteract changes in reproductive output? Glob. Change Biol. 30, e16991 (2024).

    CAS  Google Scholar 

  160. Mancino, C., Canestrelli, D. & Maiorano, L. Going west: range expansion for loggerhead sea turtles in the Mediterranean Sea under climate change. Glob. Ecol. Conserv. 38, e02264 (2022).

    Google Scholar 

  161. Santidrián Tomillo, P., Tomás, J., Marco, A., Panagopoulou, A. & Tavecchia, G. Environmental changes in the Mediterranean Sea could facilitate the western expansion of loggerhead turtles. Mar. Ecol. Prog. Ser. 728, 145–161 (2024).

    Google Scholar 

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Acknowledgements

G.C.H. is supported by the Bertarelli Programme in Marine Science (BPMS).

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Authors and Affiliations

  1. Deakin Marine Research and Innovation Centre, School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia

    Graeme C. Hays & Jacques-Olivier Laloë

  2. Marine Mammal and Turtle Division, NOAA-Southwest Fisheries Science Center, La Jolla, CA, USA

    Jeffrey A. Seminoff

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  2. Jacques-Olivier Laloë
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Indian Ocean-South-East Asian Marine Turtle Memorandum of Understanding: https://www.cms.int/iosea-turtles/en

Inter-American Convention for the Protection and Conservation of Sea Turtles: http://www.iacseaturtle.org/

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Hays, G.C., Laloë, JO. & Seminoff, J.A. Status, trends and conservation of global sea turtle populations. Nat. Rev. Biodivers. 1, 119–133 (2025). https://doi.org/10.1038/s44358-024-00011-y

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