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Reef Map · Palawan and the Sulu Sea

Tubbataha and the central Sulu Sea

Tubbataha Reefs Natural Park, Cagayancillo and the Sulu Sea atolls

About 1,542 words · 28 numbered sources · Updated 2026-11-13

The Philippines' reference reef. A remote, uninhabited no-take World Heritage park in the middle of the Sulu Sea, with some of the highest reef-shark densities recorded anywhere, long-term coral benchmarks from De La Salle University, and recent declines that researchers are still trying to explain.

Geography and reef types

Tubbataha Reefs Natural Park lies in the middle of the Sulu Sea, in the municipality of Cagayancillo, Palawan. UNESCO lists it at 96,828 ha, and Republic Act No. 10067 (2010) gives an approximate area of 97,030 ha, including islets, seabed and airspace 1,2. The park includes the North and South Atolls and Jessie Beazley Reef, a small emergent cay. It has extensive reef flats and lagoons, walls that drop more than 100 m, and surrounding open sea about 750 m deep on average 1. RA 10067 also sets a 10-nautical-mile buffer zone around the park 2. The nearest inhabited islands are in Cagayancillo, where a separate, partly no-take MPA network was declared in 2016 14.

The reefs are a natural laboratory for geology as well as ecology. UP Diliman geologists have mapped submerged reef terraces at Tubbataha and Apo Reef and used them to read sea-level history during the last deglaciation 21.

Biodiversity

UNESCO's statement of Outstanding Universal Value describes about 360 coral species, almost 90% of Philippine corals, and an estimated 700 fish species. It lists eleven species of cetaceans and eleven of sharks 1. It notes the world's highest known densities of whitetip reef sharks, nesting by green and hawksbill turtles, and seven breeding seabird species on Bird Islet and South Islet 1. A recent fish survey by Silliman University, the Smithsonian and partners recorded 534 species. It estimated that richness across all surveyed stations would level off near 603, and described the fauna as distinctively oceanic. It is a preprint and not yet peer-reviewed 12. The park sits within the central Philippine region that Carpenter and Springer identified as the global peak of marine shore-fish richness 4.

Field studies from Philippine institutions support the UNESCO account:

  • Sharks. Murray et al. (2018) recorded eight elasmobranch species in visual surveys and 14 on baited video. Densities of grey reef and whitetip reef sharks were among the highest documented worldwide, with 7.18 sharks per hectare in visual surveys 10.
  • Napoleon wrasse. Nañola et al. (2020; UP Mindanao, BFAR-NFRDI and the Tubbataha Management Office) surveyed 103 ha in 2017. They found 8.13 fish per hectare at the South Atoll and 4.20 at the North Atoll, with juveniles present. They suggest the park is both a source and a sink for this endangered species 11.
  • Manta rays. Photographs in the park's database confirmed the reef manta Manta alfredi as well as the oceanic manta 13.
  • Molluscs and giant clams. Western Philippines University (WPU) teams photo-documented 96 bivalve and gastropod species, 64 of them new park records. These include all seven Philippine giant clam species 15. Near the ranger station, Tridacna crocea reaches densities of 100–220 individuals per 100 m² 16. A province-wide WPU search for T. gigas found only 29 live animals, most of them in Tubbataha 17.

Threats

  • Ship groundings. On 17 January 2013, the US Navy minesweeper USS Guardian grounded on the South Atoll. A joint team from the park, UP MSI, the UP National Institute of Physics, BFAR, DLSU and WWF measured 2,345.67 m² of damage 22. The United States paid ₱87 million (about US$1.97 million) in 2015, to be used for rehabilitation and protection 23. In April 2013 the Chinese fishing vessel F/V Min Long Yu grounded on the North Atoll. The park reported 3,902 m² of damage and found hundreds of dead pangolins on board 24. Heij et al. (2013) analysed ship incident risk around Tubbataha, and the park was later designated a Particularly Sensitive Sea Area 19,20.
  • Poaching. WPU researchers found topshell (Tectus niloticus) abundance in 2008 was 75% lower than in 2006 after heavy poaching. Of 33 poaching apprehensions since 2004, 15 involved topshells 25.
  • Nutrients and benthic change. These remain possible drivers on the South Atoll 6,7.
  • Wider threats. UNESCO also lists shipping, marine litter, fishing, marine pollution and oil exploration. It notes that protecting the property requires measures beyond its boundaries 1.

Management and protected areas

Tubbataha was inscribed on the World Heritage List in 1993 and extended in 2009. It is also a Ramsar site 1. RA 10067 makes the park a protected area under both the NIPAS Act and Palawan's Strategic Environmental Plan. It sets a no-take policy and a multi-stakeholder Tubbataha Protected Area Management Board 2. The law requires anyone who damages the reef to pay administrative fines and the cost of restoration. It sets heavy penalties for poaching by foreign vessels, including fines of US$100,000 2.

Financing has been a model for other parks. Tongson and Dygico (2004) describe how a 1999 survey found divers willing to pay about US$41 per visit. This led to a two-tier fee system that covered 28% of recurring costs and nearly 41% of core protection costs after two years 26. Subade and Francisco (2014, UP Visayas) estimated that Filipinos who never visit still place value on conserving the reefs 27. Dygico et al. (2013) attribute the park's effectiveness to responsive governance incentives 8.

Strict protection does not always mean more fish than nearby areas. Salvador et al. (2024; Silliman, UP and partners) compared baited video in Tubbataha and Cagayancillo at shallow (4–12 m) and mesophotic (45–96 m) depths. Abundance and richness of large carnivorous fishes were not higher in Tubbataha, probably because fishing pressure in Cagayancillo is limited. Groupers and jacks in Cagayancillo were 2 and 10 times more abundant at mesophotic depths, suggesting that deep reefs act as refuges from fishing 14. The authors recommend expanding Cagayancillo's no-take zones while its fish assemblages are still intact 14.

Key research and studies

  • Coral benchmarks and benthic change. DLSU's long-term monitoring with the Tubbataha Management Office 5,6,7.
  • Elasmobranch and Napoleon wrasse assessments. Murray et al. (2018) and Nañola et al. (2020) 10,11.
  • Mesophotic fish assemblages. Silliman University and UP Diliman with partners 14.
  • Invertebrate inventories. WPU work on molluscs, giant clams and the effects of poaching 15,16,17,25.
  • Governance and economics. Studies of fees, valuation and governance 8,26,27, and of shipping risk and the Particularly Sensitive Sea Area designation 19,20.
  • Paleo sea level. The UP Diliman submerged-reef study 21.

Restoration work

Tubbataha's main restoration tool is protection: a no-take zone, a staffed ranger station and recovery of damages from those who harm the reef. The 2013 groundings showed both the value and the limits of this approach. Compensation was paid and the park's monitoring capacity was strengthened 23, but rubble fields from broken reef recover slowly. WPU has also studied the growth and survival of the giant clam Hippopus porcellanus in the park, which supports clam conservation work 28.

For the rest of the country, Tubbataha matters most as a yardstick and a source. UNESCO describes its role in reproduction, dispersal and colonisation across the Sulu Sea 1. Nañola et al. suggest it may seed Napoleon wrasse populations in nearby seas 11. Restoration teams elsewhere can use Tubbataha's benchmarks to set realistic targets, and its legal model of polluter-pays fines plus restoration costs for reef damage 2 is a useful template.

Open research questions

  1. What is driving the South Atoll change? Is it guano nutrients, typhoons, heat stress, or a combination 6,7?
  2. The 2024 heat event. How much bleaching and mortality occurred in the park, and how does Tubbataha's recovery compare with fished reefs?
  3. Larval supply. Can the park's role as a larval source be measured directly with genetics or biophysical models 1,11?
  4. Recovery of grounding scars. How fast are the 2013 grounding sites recovering, and would active rubble stabilisation help 22,24?
  5. Deep refuges. How should mesophotic reefs in Cagayancillo be included in no-take zoning 14?
  6. Fish inventory. The 534-species preprint should be peer-reviewed and compared with UNESCO's estimate of about 700 species 1,12.

References

  1. UNESCO World Heritage Centre. Tubbataha Reefs Natural Park (property 653bis). https://whc.unesco.org/en/list/653/
  2. Republic of the Philippines (2010). Republic Act No. 10067, Tubbataha Reefs Natural Park (TRNP) Act of 2009. https://lawphil.net/statutes/repacts/ra2010/ra_10067_2010.html
  3. Licuanan WY, Robles R, Reyes M (2019). Status and recent trends in coral reefs of the Philippines. Marine Pollution Bulletin 142: 544–550. De La Salle University. https://doi.org/10.1016/j.marpolbul.2019.04.013
  4. Carpenter KE, Springer VG (2005). The center of the center of marine shore fish biodiversity: the Philippine Islands. Environmental Biology of Fishes 72: 467–480. https://doi.org/10.1007/s10641-004-3154-4
  5. Licuanan WY, Robles R, Dygico M, Songco A, van Woesik R (2017). Coral benchmarks in the center of biodiversity. Marine Pollution Bulletin 114: 1135–1140. De La Salle University. https://doi.org/10.1016/j.marpolbul.2016.10.017
  6. Licuanan WY, Bahinting SE (2020). Changes in benthic cover in the South Atoll of Tubbataha Reefs due to possible eutrophication. Philippine Journal of Science 150 (1). De La Salle University. https://doi.org/10.56899/150.01.11
  7. Cadiz MM, Parr RA, Feliciano GNR, Alarcon R, Alaba MR, Pecson MJ, Licuanan WY (2024). Recent changes (2018–2022) in benthic cover in Tubbataha Reefs Natural Park, Sulu Sea, the Philippines. Philippine Journal of Science 153 (6B). De La Salle University. https://doi.org/10.56899/153.6b.01
  8. Dygico M, Songco A, White AT, Green SJ (2013). Achieving MPA effectiveness through application of responsive governance incentives in the Tubbataha reefs. Marine Policy 41: 87–94. https://doi.org/10.1016/j.marpol.2012.12.031
  9. Haworth BT, Cadigal GM, Zabala EC Jr, Gonzales BJ, et al. (2024). Palawan (UNESCO Biosphere Reserve), Philippines: State of the Marine Environment 2024 — Summary Brief. Palawan Council for Sustainable Development Staff, with Western Philippines University and the University of Sydney. https://pcsd.gov.ph/wp-content/uploads/2025/02/PalawanSoME_2024_Summary_press.pdf
  10. Murray R, Conales S, Araujo G, Labaja J, Snow S, Pierce SJ, Songco A, Ponzo A (2019). Tubbataha Reefs Natural Park: the first comprehensive elasmobranch assessment reveals global hotspot for reef sharks. Journal of Asia-Pacific Biodiversity 12: 49–56. https://doi.org/10.1016/j.japb.2018.09.009
  11. Nañola C, Paradela MA, Songco A, Pagliawan MR, Alarcon R, Santos MD (2020). First report on the density and size frequency distribution of the Napoleon wrasse, Cheilinus undulatus, in the Tubbataha Reefs Natural Park, Philippines. Philippine Journal of Science 150 (1). UP Mindanao and BFAR-NFRDI. https://doi.org/10.56899/150.01.18
  12. Gedoria GT, Stiefel KM, Williams J, Songco A, Carpenter K (2026). The fish fauna of Tubbataha Reefs is highly biodiverse and distinctively oceanic. Preprint (EcoEvoRxiv), not peer-reviewed. Silliman University and partners. https://doi.org/10.32942/X2XM3B
  13. Aquino MT, Songco A, Alarcon R (2015). Notes on the presence of Manta alfredi in the Tubbataha Reefs Natural Park, Cagayancillo, Palawan, Philippines. The Palawan Scientist 7: 7–11. https://doi.org/10.69721/tps.j.2015.7.1.01
  14. Salvador ML, Utzurrum JAT, Murray R, Delijero K, Conales S, Bird CE, Gauthier DT, Abesamis RA (2024). Intact shallow and mesophotic assemblages of large carnivorous reef fishes underscore the importance of large and remote protected areas in the Coral Triangle. Aquatic Conservation: Marine and Freshwater Ecosystems 34. Silliman University and UP Diliman. https://doi.org/10.1002/aqc.4108
  15. Dolorosa RG, Picardal RM, Conales S (2015). Bivalves and gastropods of Tubbataha Reefs Natural Park, Philippines. Check List 11: 1506. Western Philippines University. https://doi.org/10.15560/11.1.1506
  16. Conales S, Bundal NA, Dolorosa RG (2015). High density of Tridacna crocea in exposed massive corals proximate the Ranger Station of Tubbataha Reefs Natural Park, Cagayancillo, Palawan, Philippines. The Palawan Scientist 7: 40. Western Philippines University. https://doi.org/10.69721/tps.j.2015.07.1.04
  17. Mecha NJM, Dolorosa RG (2020). Searching the virtually extinct Tridacna gigas (Linnaeus, 1758) in the reefs of Palawan, Philippines. The Philippine Journal of Fisheries 27(1): 1–18. Western Philippines University. https://doi.org/10.31398/tpjf/27.1.2019-0005
  18. White AT, Palaganas VP (1991). Philippine Tubbataha Reef National Marine Park: status, management issues, and proposed plan. Environmental Conservation 18: 148–157. https://doi.org/10.1017/S0376892900021731
  19. Heij C, Knapp S, Henderson R, Kleverlaan E (2013). Ship incident risk around the heritage areas of Tubbataha and Banc d'Arguin. Transportation Research Part D 25: 77–83. https://doi.org/10.1016/j.trd.2013.08.001
  20. Batongbacal JL (2019). Designation of the Tubbataha Reef Natural Park as a Particularly Sensitive Sea Area: the Philippine experience. Ocean Yearbook 33: 163–186. https://doi.org/10.1163/9789004395633_007
  21. Munar JC, Aurelio MA, Dumalagan EE, Tinacba EJC, Doctor MAA, Siringan FP (2024). Submerged reef features in Apo and Tubbataha Reefs, Philippines, revealed paleo sea-level history during the last deglaciation. Geo-Marine Letters 44. UP Diliman. https://doi.org/10.1007/s00367-024-00764-7
  22. The Philippine Star (7 April 2013). Tubbataha damage assessed at $1.4 M. https://www.philstar.com/business/agriculture/2013/04/07/927694/tubbataha-damage-assessed-14-m
  23. BBC News (18 February 2015). US pays Philippines over USS Guardian reef damage. https://www.bbc.com/news/world-asia-31514221
  24. Rappler (3 May 2013). Chinese boat caused bigger damage in Tubbataha. https://www.rappler.com/philippines/28118-chinese-boat-caused-bigger-damage-in-tubbataha/
  25. Jontila JB, Gonzales BJ, Dolorosa RG (2014). Effects of poaching on topshell Tectus niloticus population of Tubbataha Reefs Natural Park, Palawan, Philippines. The Palawan Scientist 6: 14. Western Philippines University. https://doi.org/10.69721/tps.j.2014.06.1.02
  26. Tongson E, Dygico M (2004). User fee system for marine ecotourism: the Tubbataha Reef experience. Coastal Management 32: 17–23. https://doi.org/10.1080/08920750490247463
  27. Subade RF, Francisco HA (2014). Do non-users value coral reefs? Economic valuation of conserving Tubbataha Reefs, Philippines. Ecological Economics 102: 24–32. UP Visayas. https://doi.org/10.1016/j.ecolecon.2014.03.007
  28. Dolorosa RG, Conales S, Bundal NA (2014). Shell dimension–live weight relationships, growth and survival of Hippopus porcellanus in Tubbataha Reefs Natural Park, Philippines. Atoll Research Bulletin 604. Western Philippines University. https://doi.org/10.5479/si.00775630.604

Every source above was opened and checked when this page was written. Philippine university authorship is noted where it applies. Figures are quoted from the cited source and are not independently re-measured. This page is a research overview, not legal or management advice.

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