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Reef Map · Palawan and the Sulu Sea

Northern Palawan

El Nido, Taytay, the Calamianes and the north-east Palawan coast

About 2,172 words · 34 numbered sources · Updated 2026-11-13

Karst islands, fringing reefs and fast-growing island tourism. The region shows how watershed erosion, wastewater and visitor pressure act on reefs that sit inside the Sulu Sea biogeographic region, where national surveys find the country's best-developed reefs.

Geography and reef types

Northern Palawan spans the municipalities of El Nido and Taytay on the Palawan mainland, the Calamianes island group (Busuanga, Coron, Culion and Linapacan) to the north, and the north-east coast facing the Sulu Sea, including Araceli, Dumaran and San Vicente. The landscape is dominated by karst limestone set within a mosaic of coral reefs, seagrass beds and mangroves 1. Bacuit Bay, on the western side of El Nido, is a semi-enclosed bay with fringing reefs around limestone islands, and it opens to the West Philippine Sea. The Calamianes and the north-east coast face the Sulu Sea.

Most reefs in the region are fringing reefs on island and mainland margins, interspersed with patch reefs, seagrass meadows and mangrove-lined inlets. A rapid marine biodiversity assessment of the Calamianes in February 1998 surveyed 38 sites, covering sandy slopes, walls, overhangs and shallow reef flats to 40 m depth 2. The national reef assessment led by De La Salle University places Palawan's western and northern reefs within the Sulu Sea and West Philippine Sea biogeographic regions. Among the six regions it sampled, the Sulu Sea region showed the highest hard coral cover and generic diversity, and the eastern Philippines the lowest 3.

The protected-area framework follows these features. The El Nido–Taytay Managed Resource Protected Area (ENTMRPA) covers all 18 barangays of El Nido and three barangays of Taytay. Its 90,312 ha include 54,303 ha of marine area and 36,018 ha of land 4.

Biodiversity

Palawan as a whole is a UNESCO Biosphere Reserve and records more than 1,000 species of marine fish, along with dugongs, dolphins and whale sharks 5. The region lies within the Coral Triangle. In the analysis that delineated it, the Coral Triangle holds 605 zooxanthellate coral species, about 76% of the world total 6. Analyses of shore-fish distributions place the peak of marine shore-fish richness in the central Philippines, which makes the archipelago as a whole a global biodiversity priority 7.

For the Calamianes, the 1998 Conservation International and Palawan Council for Sustainable Development (PCSD) survey recorded 303 species of zooxanthellate scleractinian corals. Its sites averaged 92 coral species each, among the highest per-site figures in that programme's surveys across Southeast Asia and Melanesia 28. The same programme's reef-fish work in the Coral Triangle, including the Calamianes, informed regional conservation priorities 9.

Some flagship invertebrates have collapsed. Researchers at Western Philippines University (WPU) report that the giant clam Tridacna gigas was considered virtually extinct in Palawan by the 1980s. Their province-wide search found only 29 live individuals, and most of them were in Tubbataha Reefs Natural Park and at some island resorts. They also recorded 97 empty shells, most of them used as decoration 10. Experts consulted for the 2024 State of the Marine Environment report listed giant clams, Napoleon wrasse, seahorses, sea cucumbers and reef-associated fishes among species groups in poor or very poor condition and in further decline 5.

Threats

Sediment from watersheds. The classic study in this region is Hodgson and Dixon's 1988 analysis for the East-West Center. Logging began in the Bacuit Bay watershed in 1985. Within a one-year study, only 11% of the commercial forest had been cut, yet erosion had already sharply increased sediment discharge into the bay. The reef nearest the Manlag River lost nearly 50% of its living coral cover, mostly after a single storm that drove several days of high sediment discharge 1617. Their economic comparison projected that continued logging would reduce gross revenue from tourism and fisheries by more than US$40 million over ten years, compared with a logging ban. Even at a 15% discount rate, the present value of lost revenue exceeded US$11 million 16. The study remains one of the most cited demonstrations that watershed management is reef management, consistent with later global syntheses on terrestrial runoff 18.

Tourism growth and wastewater. An Asian Development Bank (ADB) brief reports that tourist arrivals to Coron and El Nido rose from 76,815 in 2008 to about 903,166 in 2019, roughly 25% a year. About 85% of visitors snorkel or dive 1. The brief estimates 4.06 million tourist site visits in El Nido in 2018, 86% of them in the Bacuit Bay cluster, and 1.55 million in Coron. A survey of 24 reef tourism sites identified anchor and grounding damage, trampling, siltation from land conversion, untreated effluent, poor beach sanitation and use conflicts between fishers and resorts 1. Water quality has been a recurring concern. In early 2018, DENR declared Bacuit Bay's recreational waters contaminated, with a coliform count of 1,139 MPN per 100 mL. A Palawan State University–WPU study found coliform counts above recreational limits at nine of 11 stations in June 2018. A year later, two stations exceeded the limit 19.

Fishing pressure and the live reef fish trade. In the Calamianes, Fabinyi's ethnography documents fishers intensifying effort for the live reef food fish trade while tourism grew, and these livelihoods compete for the same reefs 20. A companion study shows a gap between live reef fish policy and practice in Palawan 21. Destructive fishing has left a legacy. The Malampaya Foundation's coral rehabilitation monitoring covers blasted reef sites in El Nido, Linapacan and Coron 22.

Climate extremes. Marine heatwaves, typhoons and crown-of-thorns outbreaks are now regular stressors 513. A moderate marine heatwave from 21 March to 4 April 2020 coincided with a reported tomato jellyfish (Crambione mastigophora) bloom in Corong-Corong Bay, El Nido. The University of the Philippines (UP) authors who documented it link such co-occurrences to the rising frequency of heatwaves in the West Philippine Sea 23.

Management and protected areas

Palawan has a distinctive legal regime. The Strategic Environmental Plan for Palawan Act (Republic Act 7611, 1992) created the PCSD and the ECAN zoning system for land and sea, and it sits on top of national protected-area law 2411. Proclamation No. 32 of 8 October 1998 declared the El Nido Marine Reserve a Managed Resource Protected Area under the NIPAS Act 25. It grew out of a 1984 marine turtle sanctuary of about 36,000 ha and later took in three barangays of Taytay 4. Under ECAN, coral reefs in good to excellent condition are designated core zones free of human activity 11.

The Calamianes show the importance of indigenous tenure. In 2004 the National Commission on Indigenous Peoples approved a Certificate of Ancestral Domain Title of 24,520 ha for the Tagbanwa of Coron Island, including 17,012 ha of sea. It was among the first such titles to include ancestral waters 26. Tourism carrying capacity is a newer tool. The ADB technical assistance set initial environmental carrying capacities for 24 marine tourism sites in Coron and El Nido and recommended phasing in limits with monitoring 1.

Monitoring is being standardised. Through a project with the Australian Institute of Marine Science, PCSD trained local personnel. Under PCSD Resolution 24-1015 it adopted the ReefScan imaging system and the ReefCloud platform for coral reef monitoring across Palawan and Puerto Princesa 27.

Key research and studies

  • Sedimentation ecology and economics (1986–1988). Hodgson's University of Hawai'i dissertation and Hodgson and Dixon's East-West Center paper on Bacuit Bay 1617.
  • Biodiversity baselines (1998–2002). The Conservation International rapid assessment of the Calamianes, with Veron and Fenner's coral inventory and Allen and Werner's fish assessment 29.
  • Fisheries, food webs and spatial planning (2014–2018). Under the Capturing Coral Reef and Related Ecosystem Services (CCRES) project, the UP Marine Science Institute (UP MSI), De La Salle University and the University of Queensland surveyed reef condition, fish, turf algae and coral recruits across Bacuit Bay. They also measured currents and bathymetry in Lio and Bacuit bays. The data fed the Fish SPACE fisheries model and the Reef React reef-complexity model 28.
  • Local university science. WPU and Palawan State University publish reef condition, water quality and threatened-species studies in The Palawan Scientist and the Philippine Journal of Fisheries 101219. UP Cebu and UP Diliman scientists have analysed marine heatwaves off El Nido 23.
  • Province-wide synthesis. The 2024 State of the Marine Environment report, by PCSD staff, WPU, the Provincial Agriculturist's office, the University of Sydney and GRID-Arendal 5.

Restoration work

Restoration in the region is recent and mostly led by Philippine institutions. In May 2024, the ACIAR-supported larval programme cultured millions of coral larvae from spawning colonies and released them on reefs at Port Barton Marine Park, San Vicente. It involved UP MSI, Southern Cross University, WPU and the San Vicente local government 29. The method builds on the larval-enhancement trials UP MSI and Southern Cross ran in north-western Luzon 30.

In Taytay's Shark Fin Bay, the Sulubaaï Environmental Foundation installed about 300 rubble-stabilising "Sulu-Reef-Prosthesis" structures in 2024, supporting about 3,000 coral colonies. The foundation reports 76% survival of coral cuttings across about 30 species 31. The Malampaya Foundation reports survival of up to 50% at rehabilitated blasted-reef sites in El Nido, Linapacan and Coron. It also runs giant clam, topshell and abalone restocking with WPU 2213.

Two institutional developments point to a larger research footprint. On 10 October 2025, Palawan State University, WPU and DENR-MIMAROPA signed an agreement to establish marine scientific research stations in El Nido and at Snake Island 32. On 25 May 2026, the GEF-supported Coral Reef Rescue Project was launched in the Palawan Biosphere Reserve, with PCSD as national technical facilitator. It focuses on climate-refuge reefs in El Nido, Taytay and Dumaran 33. That framing draws on global portfolio analyses that rank reefs by their likely resilience to climate change and their connectivity 34.

Open research questions

  1. What did the 2024 heatwave do to Bacuit Bay? Satellite heat stress was the highest on record 14, but no quantitative post-event survey has been published. A repeat of the ECAN and CCRES sites would give the first before-and-after comparison 1128.
  2. How much of present reef condition is set by land? The 1980s logging study 16 has not been followed by a modern sediment and nutrient budget that covers roads, resorts and urban wastewater in El Nido and Coron.
  3. Do carrying-capacity limits work? The ADB framework 1 proposes phased limits. Testing them needs before-and-after control-impact monitoring of trampling, anchoring and water quality at limited and unlimited sites.
  4. Where are the climate refugia, and are they connected? Portfolio analyses 34 work at coarse scales. Local temperature loggers, larval-dispersal models (building on the CCRES current surveys 28) and genetic studies could test which northern Palawan reefs act as sources.
  5. Can larval and substrate methods scale cost-effectively? Port Barton and Shark Fin Bay give early evidence 2931. Survival, growth and heat tolerance of outplanted cohorts over several years remain unreported.
  6. What does co-management look like on titled ancestral waters? The Coron Island title 26 invites research on how Tagbanwa governance, tourism permits and scientific monitoring can be aligned.

References

  1. Liabastre T, Rieder L, Leung L (2022). Carrying Capacity Assessment for Tourism in Coron and El Nido: A Step toward Sustainable Management of Marine Ecosystems. ADB Briefs No. 212. Asian Development Bank. https://doi.org/10.22617/BRF220176
  2. Werner TB, Allen GR (eds.) (2000). A Rapid Marine Biodiversity Assessment of the Calamianes Islands, Palawan Province, Philippines. RAP Bulletin of Biological Assessment 17. Conservation International and Palawan Council for Sustainable Development. https://portals.iucn.org/library/node/26253
  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. Coral Triangle Initiative / MTPAN. El Nido–Taytay Managed Resource Protected Area: At a Glance (fact sheet). https://www.coraltriangleinitiative.org/sites/default/files/resources/MTPAN_ENTMRPA_Fact%20Sheet.pdf
  5. Haworth BT, Cadigal GM, Zabala EC Jr, Gonzales BJ, Jalover-Par CLS, Dolorosa RG, Gonzales-Plasus MM, Jontila JBS, Cabrestante MP Jr, Bruce E, Baker E (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
  6. Veron JEN, DeVantier LM, Turak E, Green AL, Kininmonth S, Stafford-Smith M, Peterson N (2009). Delineating the Coral Triangle. Galaxea, Journal of Coral Reef Studies 11: 91–100. https://doi.org/10.3755/galaxea.11.91
  7. 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
  8. Fenner D, Muir P (2008). Reef corals of the northwestern lagoon of Grande-Terre, New Caledonia. In: RAP Bulletin of Biological Assessment 53, Conservation International (compares per-site and total coral richness with the 1998 Calamianes survey by Veron and Fenner). https://doi.org/10.1896/054.053.0102
  9. Allen GR, Werner TB (2002). Coral reef fish assessment in the 'Coral Triangle' of southeastern Asia. Environmental Biology of Fishes 65: 209–214. https://doi.org/10.1023/A:1020093012502
  10. 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
  11. University of the Philippines Los Baños, College of Human Ecology (for the Municipality of El Nido and PCSD). Municipality of El Nido ECAN Resource Management Plan 2015–2020. https://pcsd.gov.ph/wp-content/uploads/2020/12/3-Municipality-of-El-Nido-ECAN-Resource-Management-Plan-2015-2020.pdf
  12. Climaco R, Aludia GM, Mecha NJM, Cornel AR, et al. (2022). Status of coral reefs, butterflyfishes, and benthic macro-invertebrates in Araceli and Dumaran, Palawan, Philippines. The Palawan Scientist 14(2): 54–64. Western Philippines University. https://doi.org/10.69721/TPS.J.2022.14.2.07
  13. Malampaya Foundation Inc. (2025). 2024 Chairman's Report. https://www.malampayafoundation.org/news/2024-chairmans-report
  14. NOAA Coral Reef Watch. Regional Virtual Station time series: Western Philippines (daily SST, HotSpot, degree heating weeks and Bleaching Alert Area, 1985–present). https://coralreefwatch.noaa.gov/product/vs/data/western_philippines.txt
  15. NOAA Coral Reef Watch. Methodology, product description and data availability for the daily 5 km products (degree heating week thresholds). https://coralreefwatch.noaa.gov/product/5km/methodology.php
  16. Hodgson G, Dixon JA (1988). Logging versus Fisheries and Tourism in Palawan: An Environmental and Economic Analysis. East-West Environment and Policy Institute, East-West Center, Honolulu. http://hdl.handle.net/10125/21626
  17. Hodgson G (1989). The effects of sedimentation on Indo-Pacific reef corals. PhD dissertation, University of Hawai'i. http://hdl.handle.net/10125/10314
  18. Fabricius KE (2005). Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis. Marine Pollution Bulletin 50: 125–146. https://doi.org/10.1016/j.marpolbul.2004.11.028
  19. Cayabo GDB, Omar DM, Mabuhay-Omar JA, Bacosa HP (2021). Bacteriological assessment of the recreational water of Bacuit Bay, El Nido, Palawan, Philippines. The Palawan Scientist 13(1): 31–43. Palawan State University and Western Philippines University. https://doi.org/10.69721/TPS.J.2021.13.1.04
  20. Fabinyi M (2010). The intensification of fishing and the rise of tourism: competing coastal livelihoods in the Calamianes Islands, Philippines. Human Ecology 38: 415–427. https://doi.org/10.1007/s10745-010-9329-z
  21. Fabinyi M, Dalabajan D (2011). Policy and practice in the live reef fish for food trade: a case study from Palawan, Philippines. Marine Policy 35: 371–378. https://doi.org/10.1016/j.marpol.2010.11.001
  22. Malampaya Foundation Inc. (2024). 2023 Chairman's Report. https://www.malampayafoundation.org/news/2023-chairmans-report
  23. Quilestino-Olario R, Concolis BMM, Atup DPD, Cortes A, Yñiguez AT, Edullantes B (2023). Co-occurrence of a marine heatwave and a reported tomato jellyfish (Crambione mastigophora Maas, 1903) bloom in March 2020 at El Nido, Palawan, Philippines. Plankton and Benthos Research 18: 93–105. University of the Philippines Cebu and UP Diliman. https://doi.org/10.3800/pbr.18.93
  24. Republic of the Philippines (1992). Republic Act No. 7611, Strategic Environmental Plan (SEP) for Palawan Act. https://lawphil.net/statutes/repacts/ra1992/ra_7611_1992.html
  25. Republic of the Philippines (1998). Proclamation No. 32, declaring the El Nido Marine Reserve a Managed Resource Protected Area. https://lawphil.net/executive/proc/proc1998/proc_32_1998.html
  26. Reyes GB, Naguit SC, Arju M, Aguilar RK (2025). The Calamian Tagbanwa reclaim and revitalize ancestral waters in the Philippines. ICCA Consortium. https://www.iccaconsortium.org/wp-content/uploads/2025/07/report-the-calamian-tagbanwa-reclaim-and-revitalize-ancestral-waters-in-the-philippines.pdf
  27. Palawan Council for Sustainable Development (2024). Successful project closing workshop marks key milestone in project completion for the MRI-AIMS project. https://pcsd.gov.ph/successful-project-closing-workshop-marks-key-milestone-in-project-completion-for-the-mri-aims-project/
  28. Capturing Coral Reef and Related Ecosystem Services (CCRES) (2018). Site report: El Nido, Philippines. University of Queensland and UP Marine Science Institute, via GEF IW:LEARN. https://www.iwlearn.net/documents/download/9766608d-c91e-4c61-a247-c9466f66b3c3
  29. Palawan News (6 June 2024). Coral spawning in Port Barton to be monitored closely during La Niña. https://palawan-news.com/coral-spawning-in-port-barton-to-be-monitored-closely-during-la-nina/
  30. dela Cruz DW, Harrison PL (2017). Enhanced larval supply and recruitment can replenish reef corals on degraded reefs. Scientific Reports 7: 13985. UP Marine Science Institute and Southern Cross University. https://doi.org/10.1038/s41598-017-14546-y
  31. Blancpain Ocean Commitment (2025). Pangatalan Sea Academy project (with Sulubaaï Environmental Foundation). https://www.blancpain-ocean-commitment.com/en/expeditions/pangatalan-sea-academy-project
  32. Palawan News (13 October 2025). DENR, academe team up to establish research stations in El Nido. https://palawan-news.com/denr-academe-team-up-to-establish-research-stations-in-el-nido/
  33. DENR Foreign-Assisted and Special Projects Service (2026). Resilient coral reefs, resilient communities: Coral Reef Rescue Project officially launched in Palawan. https://fasps.denr.gov.ph/resilient-coral-reefs-resilient-communities-coral-reef-rescue-project-officially-launched-in-palawan/
  34. Beyer HL, Kennedy EV, Beger M, Chen CA, Cinner JE, Darling ES, Eakin CM, Gates RD, et al. (2018). Risk-sensitive planning for conserving coral reefs under rapid climate change. Conservation Letters 11: e12587. https://doi.org/10.1111/conl.12587

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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