Environment

Coastal Uplift in Sarangani Exposes Coral Reefs and Kills Marine Life

July 1, 2026 · Joshua S Bariñan

The magnitude 7.8 earthquake on June 8 pushed up the seabed along parts of the Sarangani coast, draining shallow waters and leaving coral reefs and seagrass exposed to the air. Marine life in the affected zone has started to die, and the Department of Environment and Natural Resources has opened a scientific study of the change. Officials say parts of the coastline may have shifted for good.

Coastal Uplift in Sarangani Exposes Coral Reefs and Kills Marine Life image

An aerial survey and field check on June 11 found the seabed in Barangay Pangyan, Glan rose by about two meters and the shoreline moved out by roughly 200 meters, based on initial PHIVOLCS observations. Reefs, seagrass, fish, eels, and shellfish left above water have begun to rot.

What the Survey Found

Teams from the Philippine Institute of Volcanology and Seismology and the Mines and Geosciences Bureau in Region 12 flew the survey days after the quake. They traced the lift to movement along the Cotabato Trench, the same fault that triggered the tremor, which pushed up sections of coast in Sarangani and Davao Occidental.

The Pangyan Marine Sanctuary was among the worst affected. Residents reported that the water stayed unusually low and that a foul smell rose from the decaying reef life left stranded in the open air.

The DENR Study

PENRO Sarangani first sent personnel to confirm the reports on the ground. The DENR in Region 12 then began a formal scientific study on June 16, working with the Mines and Geosciences Bureau and local governments.

The investigation will measure how much habitat was lost and document the geological shift, so officials can judge whether similar changes hit other parts of the coast.

Scale of the Damage

An initial DENR assessment placed the loss to marine resources at around P70 billion. Teams have surveyed about 340 hectares of coral reef and seagrass across five Glan barangays, Batulaki, San Jose, Pangyan, Burias, and Small Margus, and expect the figure to rise as validation continues.

The exposed zone includes habitat used by dugong and sea turtles. In Purok Tamparan alone, about 100 fishers lost access to their usual grounds as boats were left stranded, and coastal tourism sites around Gumasa felt the effect.

Safety Warning

In a June 16 advisory, the DENR told the public to stay away from the shifted shorelines and to avoid touching stranded marine life because of the biological hazard from rotting organisms.

Only the Environmental Management Bureau and the Bureau of Fisheries and Aquatic Resources are cleared to handle cleanup and sanitation. Residents were asked to wait for official clearing before returning to the exposed flats.

Wider Monitoring

Rangers from the Sarangani Bay Protected Seascape are checking other sites around the bay for signs of similar uplift and habitat damage.

The office asked coastal residents to report new cases as validation work continues, since the full reach of the change is still being mapped.

Sources

  • GMA NewsDENR-12 probe and the survey findings in Glan.
  • PhilstarDENR investigation of the coastal uplift.
  • SunStarConfirmation of the uplift after the magnitude 7.8 quake.
  • Brigada NewsMarine life die off and exposed coral reefs.
  • Daily TribunePENRO ground validation of the reported uplift.
  • Cebu Daily NewsReport on the exposed seabed in Sarangani.
  • Informed PhilippinesDENR statement on the shoreline change and habitat die off.
  • MindaNewsInitial P70 billion damage estimate and the 340 hectares assessed across five Glan barangays.