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Reef Map · Luzon

Bolinao and the Lingayen Gulf

North-western Luzon, Pangasinan and La Union

About 1,608 words · 25 numbered sources · Updated 2026-11-13

The Philippines' main field laboratory for reef restoration science. The UP Marine Science Institute's Bolinao Marine Laboratory has tested coral larval reseeding, giant clam and sea urchin restocking, and coral transplantation here for decades, against heavy pressure from mariculture, sediment and storms.

Geography and reef types

The Lingayen Gulf is a broad embayment on the north-western coast of Luzon. It is bordered by Pangasinan to the south and west and La Union to the east, and it opens north to the West Philippine Sea. On its western margin, the Bolinao–Anda Reef Complex extends across the shallow shelf around Cape Bolinao, Santiago Island and the coast of Anda. It combines fringing reefs, reef flats, a large lagoon, seagrass meadows and channels. The Hundred Islands of Alaminos sit further south-east: more than a hundred small limestone islands that local government describes as uplifted ancient coral, set in shallow water with fringing reefs 12.

Hydrodynamic models calibrated with field data by the Tokyo Institute of Technology and the University of the Philippines show strong monsoon seasonality. During the south-west monsoon, there is strong one-way larval connectivity from reefs on the western side of the gulf to those on the east. During the north-east monsoon, western coastal ecosystems are more exposed to sediment and nutrient loads from the Agno River 3. The region is also exposed to typhoons, heavy rain and freshwater seepage, all of which have affected restoration trials 4.

Biodiversity

The Lingayen Gulf supports reef, seagrass and mangrove habitats and a large municipal fishery. Reef fisheries at Cape Bolinao were among the earliest documented in the country, including a 1991 analysis of species composition, abundance and diversity in reef catches 5. The reef complex also supported populations of high-value invertebrates that have been heavily depleted. Restoration programmes for giant clams and the collector sea urchin Tripneustes gratilla were developed here for that reason 67.

Coral communities include branching Acropora, Porites, Pavona and Hydnophora, which have all been used in local restoration experiments 8910. Seasonal coral spawning is regular enough to support larval culture. UP MSI scientists have collected, cultured and settled larvae of Acropora tenuis and Acropora loripes from local colonies 910. They have also collected and cryobanked pocilloporid larvae monthly at Bolinao 11.

Threats

Mariculture and eutrophication. This is the region's signature threat. Milkfish pens and cages in Bolinao grew from 242 in 1995 to 1,170 in 2001. A 2000 municipal ordinance had set the allowable number at 544 15. Over a decade, ammonia rose by 56%, nitrite by 35%, nitrate by 90% and phosphate by 67%. In 2002, a massive fish kill coincided with the first reported Philippine bloom of the dinoflagellate Prorocentrum minimum, after dissolved oxygen fell below 2.0 mg per litre in stratified water 1516. The UP MSI authors link these changes to unconsumed feed and faeces in a shallow, poorly flushed area whose water residence time was itself changed by the structures 15.

Sediment and nutrients from rivers. The Agno River is a major seasonal source of sediment and nutrients for reefs on the western side of the gulf 3. Development trajectories in the Lingayen Gulf, including aquaculture, urban growth and fishing, have been analysed by Conservation International and UP authors for their impacts on reef use 17.

Fishing pressure and invertebrate collection. The depletion of giant clams and sea urchins is documented by the restocking programmes designed to reverse it 67.

Predation and storms. Crown-of-thorns starfish (Acanthaster planci) and the snail Drupella caused high mortality among coral transplants in UP MSI trials 8. Typhoons, heavy rain and bleaching repeatedly set back nursery and transplant work 4.

Management and protected areas

The Lingayen Gulf was declared an Environmentally Critical Area, to be managed as a special coastal management area, by Proclamation No. 156 of 25 March 1993 2. The Hundred Islands National Park, about 1,844 ha, was reserved under Proclamation No. 667 in the Commonwealth era 1. It was later administered by the Philippine Tourism Authority and, from 2005, by the City of Alaminos 2. To the north and south, the Expanded NIPAS Act of 2018 legislated the Agoo–Damortis Protected Landscape and Seascape in La Union (10,774.68 ha) and the Masinloc and Oyon Bay Protected Landscape and Seascape in Zambales (7,558 ha) 18.

Municipal fisheries management relies on local ordinances, sanctuaries and FARMCs under the Fisheries Code. These include caps on mariculture structures like Bolinao's 2000 ordinance, which proved hard to enforce 1519. In the sea urchin programme, higher recruitment at Lucero was partly attributed to enforced sanctuary rules, size limits and broodstock cages, which shows that local regulation and restocking work together 7.

Key research and studies

The Bolinao Marine Laboratory of UP MSI is the centre of gravity for reef restoration research in the country. Key strands include:

  • Coral larval enhancement. dela Cruz and Harrison (UP MSI and Southern Cross University) supplied about 400,000 A. tenuis larvae to each of four enclosed plots on degraded reef in the north-western Philippines. After three years, a mean of 2.3 colonies per square metre survived in each plot. Colonies averaged 16.1 cm in diameter and had already spawned, while natural recruitment produced no new visible colonies 9. A follow-up with A. loripes in the Bolinao–Anda Reef Complex (June 2014) introduced about 300,000 larvae per 6 × 4 m plot. Settlement averaged 27.8 spat per tile in seeded plots and zero in controls. After 35 months, 47 colonies survived, with a mean diameter of 7.9 cm, at a production cost of about US$35.20 per surviving colony 10. These are among the most-cited field demonstrations of larval reseeding anywhere.
  • Coral transplantation design. Cabaitan, Yap and Gomez compared single-species and mixed-species transplant plots of Porites cylindrica, Pavona frondifera and Hydnophora rigida. P. cylindrica survived well in all treatments, and P. frondifera did better mixed with P. cylindrica at wave-exposed sites 8. Sabater and Yap tested electrochemical (mineral accretion) treatment of P. cylindrica transplants 20.
  • Coral gardening under disturbance. Israeli–Philippine trials of nurseries and transplantation in Bolinao from 2005 to 2007 recommended depth-flexible nurseries, prioritising robust species and genotypes, and careful timing and site selection 4.
  • Invertebrate restocking. UP MSI's giant clam culture and restocking programme, reviewed by Gomez and Mingoa-Licuanan, offers lessons for other countries 6. The T. gratilla programme combined sea-cage grow-out with reseeding. It found that reseeded urchins grew well but suffered 91–99% natural mortality, and it recommended pairing sanctuary networks with grow-out culture 7.
  • Water quality and harmful algal blooms. UP MSI studies link mariculture density to eutrophication, blooms and fish kills 1516.
  • People and restoration. A 2024 study by UP MSI, De La Salle University, James Cook University and Southern Cross University examined how fishers in Tondol, north-western Philippines, perceive coral restoration, and what that implies for designing projects 21.

Restoration work

Restoration in this region is unusually diverse.

  • Larval reseeding remains UP MSI's flagship method, and it has been exported to other sites, including Port Barton in Palawan 91022.
  • Larval cryobank. In August 2025, UP MSI announced the Philippines' first coral-larvae cryobank at the Bolinao Marine Laboratory, under Dr Maria Vanessa Baria-Rodriguez. It is part of a Coral Triangle cryorepository network supported by CORDAP through the Marine Environment and Resources Foundation (MERF). Training was held at Bolinao on 1–4 December 2024 11.
  • Coral gardening in the Hundred Islands. The DOST-PCAARRD "Filipinnovation" coral restoration programme, launched in 2012, used corals of opportunity on coral nursery units. Quezon Island was the donor site, Clave Island the nursery site and Romulo Island the transplant site 2324.
  • Giant clam reseeding. The City of Alaminos reports that about 5,000 giant clams are protected in the park through reseeding with UP MSI 25.

Open research questions

  1. How much mariculture can the Bolinao–Anda system carry? The 2002 fish kill 15 showed that the cap was exceeded. A modern, enforceable carrying capacity based on residence-time modelling 3 is still needed.
  2. Do larval-reseeded populations persist and spread? The plots in 9 and 10 spawned within three years. Whether their offspring measurably increase recruitment at reef scale, and how they fare after the 2024 heatwave 13, is unknown.
  3. Can cryopreservation preserve genetic diversity for future restoration? The new cryobank 11 makes it possible to test how well thawed larvae settle and survive, and how much genetic diversity is held across seasons and species.
  4. What makes restoration socially durable? Fisher perceptions in Tondol 21 and the sanctuary–restocking link at Lucero 7 suggest governance matters as much as technique. Comparative studies across Pangasinan municipalities could test this.
  5. Which nurseries and species survive repeated storms and heat? Bolinao's record of typhoons, freshwater pulses and bleaching 4 makes it a natural test site for heat-tolerant genotypes and storm-proof nursery designs.

References

  1. Republic of the Philippines (Commonwealth). Proclamation No. 667, establishing the Hundred Islands National Park, Alaminos, Pangasinan. https://lawphil.net/executive/proc/proc1941/proc_667_1941.html
  2. City Government of Alaminos. Ecological profile: The Hundred Islands National Park. https://alaminoscity.gov.ph/ecological-profile/content/chapter2/hundred_islands_national_park.html
  3. Ashikawa K, Pokavanich T, Kartadikaria AR, Nadaoka K, Villanoy C, Herrera EC (2013). Seasonal larval dispersal characteristics and sediment discharge impacts on the coral reefs in Lingayen Gulf, Philippines towards coastal ecosystem conservation. Galaxea, Journal of Coral Reef Studies 15: 295–299. Tokyo Institute of Technology and University of the Philippines. https://doi.org/10.3755/galaxea.15.295
  4. Shaish L, Levy G, Katzir G, Rinkevich B (2010). Coral reef restoration (Bolinao, Philippines) in the face of frequent natural catastrophes. Restoration Ecology 18: 285–299. https://doi.org/10.1111/j.1526-100X.2009.00647.x
  5. Acosta AR, Turingan RG (1991). Coral reef fisheries at Cape Bolinao, Philippines: species composition, abundance and diversity. Asian Fisheries Science 4(3). https://doi.org/10.33997/j.afs.1991.4.3.003
  6. Gomez ED, Mingoa-Licuanan SS (2006). Achievements and lessons learned in restocking giant clams in the Philippines. Fisheries Research 80: 46–52. UP Marine Science Institute. https://doi.org/10.1016/j.fishres.2006.03.017
  7. Juinio-Meñez MA, Bangi HG, Malay MCD, Pastor D (2008). Enhancing the recovery of depleted Tripneustes gratilla stocks through grow-out culture and restocking. Reviews in Fisheries Science 16: 35–43. UP Marine Science Institute. https://doi.org/10.1080/10641260701678116
  8. Cabaitan PC, Yap HT, Gomez ED (2015). Performance of single versus mixed coral species for transplantation to restore degraded reefs. Restoration Ecology 23: 349–356. UP Marine Science Institute. https://doi.org/10.1111/rec.12205
  9. 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
  10. dela Cruz DW, Harrison PL (2020). Enhancing coral recruitment through assisted mass settlement of cultured coral larvae. PLoS ONE 15: e0242847. UP Marine Science Institute and Southern Cross University. https://doi.org/10.1371/journal.pone.0242847
  11. UP Marine Science Institute (7 August 2025). UP MSI to establish PH's first coral cryobank facility for coral restoration. https://msi.upd.edu.ph/up-msi-to-establish-phs-first-coral-cryobank-facility-for-coral-restoration/
  12. 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
  13. NOAA Coral Reef Watch. Regional Virtual Station time series: Northern Philippines (1985–present). https://coralreefwatch.noaa.gov/product/vs/data/northern_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. San Diego-McGlone ML, Azanza RV, Villanoy CL, Jacinto GS (2008). Eutrophic waters, algal bloom and fish kill in fish farming areas in Bolinao, Pangasinan, Philippines. Marine Pollution Bulletin 57: 295–301. UP Marine Science Institute. https://doi.org/10.1016/j.marpolbul.2008.03.028
  16. Azanza RV, Fukuyo Y, Yap-Dejeto L, Takayama H (2005). Prorocentrum minimum bloom and its possible link to a massive fish kill in Bolinao, Pangasinan, northern Philippines. Harmful Algae 4: 519–524. UP Marine Science Institute. https://doi.org/10.1016/j.hal.2004.08.006
  17. Cruz-Trinidad A, Geronimo RC, Aliño PM (2009). Development trajectories and impacts on coral reef use in Lingayen Gulf, Philippines. Ocean & Coastal Management 52: 173–180. https://doi.org/10.1016/j.ocecoaman.2008.12.002
  18. 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
  19. 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
  20. Sabater MG, Yap HT (2002). Growth and survival of coral transplants with and without electrochemical deposition of CaCO3. Journal of Experimental Marine Biology and Ecology 272: 131–146. UP Marine Science Institute. https://doi.org/10.1016/S0022-0981(02)00051-5
  21. Gomez R, Mamauag SS, Fabinyi M, dela Cruz DW, McLeod IM, Cabaitan PC, Harrison PL (2024). Implications of fisher perceptions on coral restoration in Tondol, northwestern Philippines. Ocean & Coastal Management 255: 107233. https://doi.org/10.1016/j.ocecoaman.2024.107233
  22. 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/
  23. DOST-PCAARRD. PCAARRD and Alaminos, Pangasinan bond on reef restoration strategies. https://pcaarrd.dost.gov.ph/index.php/quick-information-dispatch-qid-articles/pcaarrd-and-alaminos-pangasinan-bond-on-reef-restoration-strategies
  24. The Philippine Star (4 January 2018). Pangasinan's Hundred Islands now a coral restoration site. https://www.philstar.com/business/science-and-environment/2018/01/04/1774282/pangasinans-hundred-islands-now-coral-restoration-site
  25. City Government of Alaminos. Ecological profile: Giant clams in the HINP. https://www.alaminoscity.gov.ph/ecological-profile/content/chapter2/giant_clams_in_the_hundred_islands.html

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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