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Reef Map · Mindanao

Mindanao's reef coasts

Davao Gulf, Pujada Bay, Sarangani and northern Mindanao

About 1,486 words · 30 numbered sources · Updated 2026-11-13

Mindanao faces three seas: the Pacific, the Celebes Sea and the Bohol Sea. It holds some of the country's largest protected seascapes and a growing base of reef science in its own state universities, including Mindanao State University, Davao Oriental State University and Caraga State University, but it is less studied than Luzon or the Visayas.

Geography and reef types

Mindanao's reef coasts fall into three broad settings.

  • The Pacific seaboard. From Siargao and Surigao del Sur down to Davao Oriental, this coast faces open ocean swell and typhoon tracks. Its fringing reefs and bays include Lanuza Bay and Pujada Bay. The De La Salle University-led national assessment found the lowest hard coral cover and generic diversity of its six biogeographic regions in the eastern Philippines, which faces the Pacific 1.
  • The Celebes Sea coast. This includes the Davao Gulf, with Samal Island, and Sarangani Bay, both deep embayments opening south to the Celebes Sea.
  • The northern coast. Misamis Oriental, Lanao del Norte, Misamis Occidental and the island of Camiguin face the Bohol (Mindanao) Sea, with fringing reefs on narrow shelves.

The Zamboanga Peninsula and the Sulu Archipelago are covered in a separate region.

Pujada Bay is a semi-enclosed bay near Mati, with fringing reefs at Guang-guang, Manguihay, Lawigan, Mamali and Macambol 2. The Davao Gulf receives sediment and runoff from large river basins. UP MSI modellers have simulated sub-basin sediment yields into the gulf 3.

Biodiversity

Mindanao's southern seas remain relatively poorly described. Fish-market surveys near the Davao Gulf by Davao del Norte State College and partners measured 3,806 individuals of 139 reef and pelagic species between 2009 and 2012. They reported length–weight relationships that were new to science for 47 of them 4. Market surveys on Samal Island produced seven new fish records for the Philippine archipelago. The authors cite these as evidence of the "uniqueness of the poorly-studied fauna of the southern Philippines" 5. Caraga State University has inventoried the fish fauna of the Siargao Island Protected Landscape and Seascape 6.

Reef fish communities respond to protection here as elsewhere. Mindanao State University–Iligan Institute of Technology surveyed three marine protected areas in Misamis Oriental: Molugan, Hermano and Mambayaan. Fish diversity, abundance and biomass were moderate to very high, and they were numerically, though mostly not statistically, higher inside the MPAs than outside 7. Habitat connectivity matters too. Surveys by Hokkaido University, Mindanao State University at Naawan and UP found that more than 20% of commercial fish species used more than one of the coral, seagrass and mangrove habitats 8. The dugong grazing areas of Pujada Bay have been mapped by Davao Oriental State University researchers 9.

Threats

  • Fishing pressure and overfishing are evident in the dominance of low-value fish on degraded reefs 2 and in fishers' own reports of declining catch 15.
  • Crown-of-thorns starfish outbreaks have been documented in northern Mindanao. Camiguin Polytechnic State College recorded densities of 75 and 160 starfish per hectare at Pasil Reef and San Roque, on opposite sides of Camiguin, during removal campaigns. The authors suggest outbreaks are likely island-wide 16.
  • Sediment from river basins and mining land use affects the Davao Gulf and Lanuza Bay. Modelling work has simulated sediment yields under mining land-use change scenarios in Lanuza Bay 317.
  • Climate stress and urbanisation. Rising heat stress 13, typhoons along the Pacific seaboard, and urban growth around Davao City and General Santos add pressure. Regional reviews of urban reefs in East and Southeast Asia describe "reef compression" and shifts towards domed, low-complexity coral assemblages near cities 18.
  • Pollution. Macroplastics have been documented on beaches of the Sarangani Bay Protected Seascape, and microplastics in Siargao's surface waters and in rabbitfish 1920.

Management and protected areas

Mindanao holds some of the largest protected seascapes in the country. The Expanded NIPAS Act of 2018 legislated the following 21:

  • Siargao Island Protected Landscape and Seascape (Surigao del Norte): 283,974.77 ha
  • Sarangani Bay Protected Seascape (General Santos City and Sarangani): 210,887.69 ha
  • Pujada Bay Protected Landscape and Seascape (Davao Oriental): 20,873.43 ha
  • Initao–Libertad Protected Landscape and Seascape (Misamis Oriental): 921.02 ha
  • Baliangao Protected Landscape and Seascape (Misamis Occidental): 315.50 ha
  • Mabini Protected Landscape and Seascape (Davao de Oro, listed as Compostela Valley): 7,292.62 ha

Protected Area Management Boards govern these areas. Davao Oriental State University presented first-year results of its artificial clay reef at a special Pujada Bay PAMB meeting in July 2025 22.

Below the national layer, municipal sanctuaries under the Fisheries Code are the main tool, as in the Misamis Oriental MPAs 723. Inter-municipal alliances help coordinate them. The Lanuza Bay Development Alliance in Surigao del Sur is one of three MPA networks examined in depth in a national study of scaling up from single MPAs to networks 24.

Key research and studies

Mindanao's reef science is increasingly led by regional universities:

  • Davao Oriental State University (DORSU). Reef and fisheries studies in Pujada Bay and the Davao Gulf 2915, and monitoring of the artificial clay reef 2225.
  • Mindanao State University campuses at Naawan, Iligan (MSU–IIT) and General Santos. MSU at Naawan's Coastal Resource Management hub (CoReM) offers coral transplantation services for corals affected by coastal development. Its sustainability reporting lists transplantation at Lugait (Misamis Oriental), Bislig (Surigao del Sur) and Kauswagan (Lanao del Norte) 2627. CoReM researchers presented work on coral translocation and reef-fish ecology at the 16th International Coral Reef Symposium in Auckland in July 2026 26.
  • Caraga State University, with fish inventories of the Siargao protected area 6.
  • National syntheses that include Mindanao sites, led by De La Salle University, UP Visayas and Silliman University authors 112.

Restoration work

The best-documented current restoration project is in Pujada Bay. DORSU and the Swiss–German group rrreefs launched an artificial clay reef project in February 2024. It began with about 100 m² of terracotta modules at Manguihay, then added an 80 m² reef at Tamisan and a local clay-module production facility in Mati 2528. DORSU reported about 4,000 coral recruits on the 100 m² structure after one year 22. A separate DORSU study counted 250 fish of 27 species from 11 families six months after installation. Small, non-target damselfishes dominated, but some target herbivores were present 29.

In northern Mindanao, MSU at Naawan's transplantation service relocates corals displaced by coastal development 2627. Crown-of-thorns removal on Camiguin is a form of active reef protection that is often overlooked 16. A 2016 DOST-PCAARRD account records MSU–General Santos's role in coral restoration at Bakud Reef, Kiamba, Sarangani, after a ship grounding 30. We did not find current reporting on that site.

Open research questions

  1. How resilient are Pacific-facing reefs? National surveys find the lowest coral cover in the eastern Philippines 1. It is unresolved whether that reflects natural exposure, typhoon frequency, sediment or human use.
  2. Do clay and other artificial substrates produce lasting coral communities? Early recruitment and fish colonisation in Pujada Bay are promising 2229. Multi-year survival, species composition and heat tolerance of recruits, compared against natural reference reefs, are the key tests.
  3. What is the true biodiversity of the southern seas? New records and new length–weight relationships from market surveys 45 suggest systematic underwater biodiversity surveys of the Davao Gulf and Sarangani Bay would find more.
  4. How do mining and river basins affect reefs? Sediment-yield models 317 need to be linked to field measurements of sedimentation and coral health.
  5. How should COTS be managed? Outbreak drivers, links to nutrients, and the cost-effectiveness of removal on Camiguin and elsewhere 16 are open questions.
  6. How can large protected seascapes be monitored? Siargao and Sarangani together cover nearly 500,000 ha 21. Low-cost participatory monitoring methods, refined in Lanuza Bay 10, could be tested at that scale.

References

  1. 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
  2. Nanual BJ, Nogodula R, Jimenez LA (2012). Status of benthos and reef fish communities in Pujada Bay, Davao Oriental, Mindanao. Davao Research Journal 8: 15–28. Davao Oriental State University. https://doi.org/10.59120/drj.v8i1.35
  3. Gallentes A, Maloles PJ, Villanoy C, et al. (2020). Simulation of sub-basin sediment yields and river runoffs into Davao Gulf, Philippines. EGU General Assembly 2020 abstract. UP Marine Science Institute. https://doi.org/10.5194/egusphere-egu2020-588
  4. Gumanao GS, Saceda-Cardoza MM, Mueller B, Bos AR (2016). Length–weight and length–length relationships of 139 Indo-Pacific fish species (Teleostei) from the Davao Gulf, Philippines. Journal of Applied Ichthyology 32: 377–385. Davao del Norte State College. https://doi.org/10.1111/jai.12993
  5. Bos AR, Gumanao GS (2013). Seven new records of fish (Teleostei: Perciformes) from coral reefs and pelagic habitats in southern Mindanao, the Philippines. Marine Biodiversity Records 6. Davao del Norte State College. https://doi.org/10.1017/S1755267213000614
  6. Calagui L, Rosal JJ, Seronay RA, Calagui SI (2022). Inventory of fish fauna in Siargao Island Protected Landscape and Seascape, Surigao del Norte, Philippines. Fisheries Research 251: 106325. Caraga State University. https://doi.org/10.1016/j.fishres.2022.106325
  7. Bersaldo MJI, Dalagan GE, Duay CB, Tutor RB, Pedrosa-Gerasmio IR, Tampus AD (2026). Reef fish diversity, abundance and biomass in marine protected and unprotected areas in Misamis Oriental, Northern Mindanao, Philippines. The Philippine Journal of Fisheries 33. Mindanao State University–Iligan Institute of Technology. https://doi.org/10.31398/tpjf/33.1.2023-0003
  8. Honda K, Nakamura Y, Nakaoka M, Uy WH, Fortes MD (2013). Habitat use by fishes in coral reefs, seagrass beds and mangrove habitats in the Philippines. PLoS ONE 8: e65735. Mindanao State University at Naawan and UP Diliman. https://doi.org/10.1371/journal.pone.0065735
  9. Sanchez CC (2017). Assessment of seagrass distribution in dugong grazing areas of Pujada Bay, Mati City, Philippines. Davao Research Journal 11(2). Davao Oriental State University. https://doi.org/10.59120/drj.v11i2.369
  10. de la Rosa GE, Tabaranza DGE (2013). Building on participatory marine protected area monitoring in Lanuza Bay, southeastern Philippines. Galaxea, Journal of Coral Reef Studies 15: 300–308. Haribon Foundation. https://doi.org/10.3755/galaxea.15.300
  11. Centro JA, Eballe A, Rapiz FG, et al. (2026). Benthic cover composition and fish community structure in coral reef communities of Davao Oriental, southeastern Mindanao. East Asian Journal of Multidisciplinary Research 5(6). https://doi.org/10.55927/eajmr.v5i6.154
  12. Magdaong ET, Fujii M, Yamano H, Licuanan WY, Maypa A, Campos WL, Alcala AC, White AT, Apistar D, Martinez R (2014). Long-term change in coral cover and the effectiveness of marine protected areas in the Philippines: a meta-analysis. Hydrobiologia 733: 5–17. De La Salle University, UP Visayas, Silliman University and CCEF. https://doi.org/10.1007/s10750-013-1720-5
  13. NOAA Coral Reef Watch. Regional Virtual Station time series: Southern Philippines (1985–present). https://coralreefwatch.noaa.gov/product/vs/data/southern_philippines.txt
  14. NOAA Coral Reef Watch. Methodology, product description and data availability for the daily 5 km products. https://coralreefwatch.noaa.gov/product/5km/methodology.php
  15. Macusi ED, Camaso KL, Barboza A, Macusi ES (2021). Perceived vulnerability and climate change impacts on small-scale fisheries in Davao Gulf, Philippines. Frontiers in Marine Science 8: 597385. Davao Oriental State University. https://doi.org/10.3389/fmars.2021.597385
  16. Paderanga O, Flores NA (2024). Abundance and population size structure of the crown-of-thorns seastar in Camiguin Island, Northern Mindanao. The Philippine Journal of Fisheries 31(2): 285–290. Camiguin Polytechnic State College. https://doi.org/10.31398/tpjf/31.2.2023-0019
  17. Maloles PJ, Gallentes A, Villanoy C, et al. (2020). SWAT-based sediment yield simulation with mining land-use change scenario in Lanuza Bay, Philippines. EGU General Assembly 2020 abstract. https://doi.org/10.5194/egusphere-egu2020-12569
  18. Heery EC, Hoeksema BW, Browne NK, Reimer JD, Ang PO, Huang D, Friess DA, Chou LM, et al. (2018). Urban coral reefs: degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia. Marine Pollution Bulletin 135: 654–681. https://doi.org/10.1016/j.marpolbul.2018.07.041
  19. Acot FT, Sajorne RE, Omar NAK, et al. (2022). Unraveling macroplastic pollution in rural and urban beaches in Sarangani Bay Protected Seascape, Mindanao, Philippines. Journal of Marine Science and Engineering 10: 1532. https://doi.org/10.3390/jmse10101532
  20. Bajan S, Castillon E, Lagura ST, et al. (2026). Microplastic pollution in a Philippine protected area: evidence from Siargao Island's surface waters and Siganus spp. https://doi.org/10.1007/s44533-026-00022-y
  21. Republic of the Philippines (2018). Republic Act No. 11038, Expanded National Integrated Protected Areas System Act of 2018 (schedule of protected areas). https://elibrary.judiciary.gov.ph/thebookshelf/showdocs/2/84999
  22. Davao Oriental State University (23 July 2025). Marine life booms in Pujada Bay after artificial reef installation. https://dorsu.edu.ph/marine-life-booms-in-pujada-bay-after-artificial-reef-installation/
  23. Republic of the Philippines (1998). Republic Act No. 8550, The Philippine Fisheries Code of 1998. https://lawphil.net/statutes/repacts/ra1998/ra_8550_1998.html
  24. Horigue V (2014). Scaling up to form marine protected area networks: the role of coordination of initiatives and institutional collaborations in the Philippines. PhD thesis, James Cook University. https://researchonline.jcu.edu.au/39883/1/39883-horigue-2014-thesis.pdf
  25. rrreefs (August 2026). 2026 impact report: Pujada Bay, Philippines. https://www.rrreefs.com/2026/08/2026-impact-report-pujada-bay-philippines/
  26. Mindanao State University at Naawan. Coastal Resource Management (CoReM) Hub. https://msunaawan.edu.ph/corem/
  27. Mindanao State University at Naawan. Sustainability: SDG 14 initiatives. https://sustainability.msunaawan.edu.ph/sdg-initiatives/sdg-14
  28. Davao Oriental State University (2026). University President Ponce highlights DORSU's reef restoration initiatives at Dive Davao Summit 2026. https://dorsu.edu.ph/university-president-ponce-highlights-dorsus-reef-restoration-initiatives-at-dive-davao-summit-2026/
  29. Polestico R, Jimenez LA, Ponce AG, Bation LB, Eballe A (2026). Early fish community development in a 3D-printed artificial clay reef system in Pujada Bay, Philippines. East Asian Journal of Multidisciplinary Research 5(7): 2613–2626. Davao Oriental State University. https://doi.org/10.55927/eajmr.v5i7.191
  30. DOST-PCAARRD (12 February 2016). Restoring the country's coral reefs through Filipinnovation. https://www.pcaarrd.dost.gov.ph/index.php/quick-information-dispatch-qid-articles/restoring-the-country-s-coral-reefs-through-filipinnovation

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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