West Philippine Sea Ecosystem Imperiled

The West Philippine Sea supplies an estimated 11 percent of the country’s marine captured fisheries, sustaining roughly 300,000 fisherfolk. That figure alone explains why this body of water matters far beyond geopolitical headlines — it is a direct source of protein and income for hundreds of thousands of Filipino households. But the same waters that feed coastal communities are also the site of a rapid ecological decline that experts say is being overshadowed by the strategic and military dimensions of the dispute.

The numbers paint a stark picture. Coral reef cover has dropped from 40 percent in 2000 to just 10 percent today, with only 5 percent of reefs nationwide classified as “excellent.” Mangroves and seagrasses — the engines of coastal productivity — are declining significantly. These are not separate problems from the territorial dispute; they are deeply connected to it. As tensions have risen, the government’s response has tilted heavily toward strategic and military measures, leaving environmental and food security concerns comparatively underfunded. For a deeper look at how pollution compounds these pressures on marine ecosystems, see our coverage of coastal pollution threatening coral reefs.

What the Ecological Decline Means for Filipinos

The core issue is not just that coral is dying — it is that the ecological system connecting the West Philippine Sea to the rest of the country is unraveling. Dr. Deo Onda of the University of the Philippines Marine Science Institute explains that the South China Sea functions as a biological highway. Eggs and larvae from reefs in the Kalayaan Island Group drift with ocean currents, settling along the western Philippine coast and even reaching neighboring countries. When corals die, that highway collapses. “What will happen to the sink if the sources get cut?” Onda asked during a roundtable discussion. The answer is straightforward: fish stocks decline, and the communities that depend on them lose their livelihoods.

How Geopolitical Tensions Skew Priorities

The Philippines declared a state of national energy emergency in late March 2026 — the first country in the world to do so — as disruptions in the West Philippine Sea threatened energy supplies. That move reflects how the crisis has been framed primarily as a strategic and economic security issue. But the environmental dimension, experts argue, has been pushed to the margins.

Onda pointed out that the government’s focus on the West Philippine Sea is mirrored in marine scientific research. Security and maritime analyst Jules Amador III noted that “where there is tension, there’s more money,” meaning research vessels and funding flow disproportionately to contested waters. The result is a significant knowledge gap: the eastern seaboard and the Pacific side of the Philippines remain largely unexplored. “We barely know about the eastern seaboard of the Philippines, or at least the Pacific seaboard. We barely know,” Onda said. This uneven attention matters because the West Philippine Sea accounts for only 40 percent of the country’s territory, while the remaining 60 percent — where many coastal communities live — receives less support.

The Philippines also took a significant legislative step in November 2024 when President Ferdinand Marcos Jr. signed the Philippine Maritime Zones Act (Republic Act No. 12064) into law. The law defines the country’s internal waters, archipelagic waters, territorial sea, exclusive economic zone, and continental shelf in alignment with UNCLOS and the 2016 arbitral ruling. But Amador noted that despite this legal framework, maritime issues still occupy only a small portion of national security policy, even as they are likely to become a major foreign policy concern. The gap between legal definition and practical implementation remains wide.

What Gets Missed in the Security-First Approach

→ Scroll right to see all columns

The Blue Economy Remains Underdeveloped

Amador highlighted a fundamental problem: the Philippines’ planning system has historically focused on land, leaving marine spatial planning underdeveloped. Critical questions about where to place ports, submarine cables, and other maritime infrastructure remain largely unaddressed. The concept of a “blue economy” — sustainable use of ocean resources for economic growth — cannot advance without integrated planning that connects maritime and land-based policies. This is not a niche concern; it affects everything from trade routes to disaster response.

Community Reporting Fills a Critical Gap

Satellite tracking using Automatic Identification Systems (AIS) has a well-known blind spot: “dark vessels” that turn off their transponders. As of the third quarter of 2025, 78 incidents had been reported in the West Philippine Sea, and satellite mapping revealed significant Chinese presence around Bajo de Masinloc, Scarborough Shoal, Sabina Shoal, and Kagitingan Reef. Some reefs claimed by the Philippines show fully developed Chinese bases. In this environment, community-based reporting becomes essential for real-time situational awareness. Fisherfolk on the water see what satellites cannot — but they also face harassment when trying to access traditional fishing grounds, compounded by climate-related events and typhoons.

Unregulated Activities Disrupt Traditional Fishing

Unilateral measures such as fishing bans and the creation of so-called “nature reserves” by other claimants have disrupted traditional fishing practices and degraded marine habitats. These actions place additional pressure on local communities who have fished these waters for generations. The irony is that measures ostensibly meant to protect marine environments can backfire when they are imposed without local input or enforcement capacity, leaving habitats unmonitored and fishing communities displaced.

What Can Be Done: Practical Steps for a Broader Approach

Expand Marine Scientific Research Beyond Contested Waters

The disparity in research allocation is stark. Onda noted that ship time and funding are concentrated in the West Philippine Sea because that is where geopolitical attention — and money — flows. To correct this, the government and academic institutions need to deliberately allocate resources to the eastern seaboard and southern waters. This means dedicating research vessel schedules, funding proposals, and graduate student projects to areas that are currently understudied. Without baseline data on reef health, fish stocks, and water quality in these regions, any policy response is flying blind. The dual threats of climate change and pollution affecting Philippine waters make this data collection urgent.

Integrate Marine Spatial Planning into National Policy

The passage of the Philippine Maritime Zones Act in 2024 was a critical legal step, but law alone does not create a plan. Amador’s point about the lack of integrated planning between maritime and land-based economic policies is a practical bottleneck. Local government units, national agencies, and the private sector need a coordinated framework that answers basic questions: Where should fishing ports be located to serve coastal communities? Where can submarine cables be laid without damaging reefs? How do shipping lanes intersect with fishing grounds? These are not abstract questions — they determine whether the blue economy can function.

• 1
  Map Existing Maritime Uses

  Conduct a national inventory of fishing grounds, shipping lanes, cable routes, protected areas, and energy infrastructure. This baseline is essential for any spatial plan.

• 2
  Align LGUs and National Agencies

  Create a cross-agency task force that includes the Department of Environment and Natural Resources, the Department of Agriculture (Bureau of Fisheries and Aquatic Resources), the Philippine Coast Guard, and local government units to ensure plans are coordinated.

• 3
  Fund Community-Based Monitoring

  Equip fisherfolk organizations with training and simple reporting tools (mobile apps, radio) to document illegal fishing, habitat damage, and foreign vessel activity. Their on-water observations complement satellite data.

Support Community-Based Maritime Monitoring

The “Eyes on the Sea” conference highlighted a practical solution: training local communities to report what they see. With Philippine maritime territory roughly seven times larger than its land area, government patrols alone cannot cover every reef and fishing ground. Fisherfolk who are already on the water daily can provide real-time data on illegal fishing, coral damage, and foreign vessel movements. This approach also addresses the “dark vessel” problem — when ships turn off their transponders, human observation becomes the only reliable source of information. Programs that provide training, simple reporting tools, and protection from harassment can turn a vulnerability into a strength.

Pursue Joint Development Where Possible

President Marcos has suggested that the disruption in the West Philippine Sea could serve as an impetus for Manila and Beijing to explore joint oil and gas development. While this remains a politically sensitive path, the logic is that shared economic interests can create incentives for cooperation that pure territorial negotiations cannot. The same principle could apply to fisheries management and marine conservation — joint scientific research and coordinated patrols against illegal fishing could build trust while protecting shared resources. The Code of Conduct negotiations remain one of the Philippines’ core aspirations, but practical cooperation on environmental issues may move faster than the political track.

Frequently Asked Questions

Looking Ahead

The West Philippine Sea will remain a flashpoint, but the health of its ecosystems affects far more than territorial claims. Coral reefs, mangroves, and seagrasses do not recognize maritime boundaries — they sustain fisheries that feed millions across Southeast Asia. The Philippines has taken important legal steps with the Maritime Zones Act, and community-based monitoring offers a practical way to fill surveillance gaps. But the deeper challenge is rebalancing attention: the 60 percent of Philippine waters outside the West Philippine Sea need research, protection, and integrated planning just as urgently. If this was useful, you might also want to read how climate change and pollution compound environmental risks across the country.

Sources

Coastal pollution threatens coral reefs — Explores how land-based pollution directly damages the same reef ecosystems discussed in this article.

Dual threats of climate change and pollution in the Philippines — Examines how overlapping environmental pressures affect marine and coastal communities nationwide.

Experts warn of rapid marine ecosystem decline amid focus on WPS issues. Inquirer.net, 2025.

Eyes on the Sea conference pushed community maritime monitoring. Tribune.net.ph, 2025.

The Philippines in 2026: Between alliance commitment and strategic hedging. The Diplomat, 2026.