Offshore wind project in San Miguel Bay seen to threaten Irrawaddy dolphins, biodiversity

By Rhaydz B. Barcia

LEGAZPI CITY --- A proposed 500-megawatt offshore wind power project in San Miguel Bay, Camarines Sur may pose risks to marine biodiversity, including the critically endangered Irrawaddy dolphins, according to a University of the Philippines marine scientist.

Dr. Lemnuel V. Aragones, professor at the University of the Philippines Institute of Environmental Science and Meteorology (UP-IESM) and principal investigator of the Marine Mammal Research and Conservation Laboratory, said underwater vibrations, noise, and electromagnetic fields generated by the project could negatively affect marine life.

“Yes, through the sounds from vibrations and electromagnetic fields produced underwater, there will be impacts on biodiversity,” Aragones said.

Aragones said the Irrawaddy dolphins in San Miguel Bay represent the third identified population in the Philippines, separate from those in Malampaya Sound in Palawan and the Iloilo-Guimaras-Negros Occidental waters. These populations do not interact and must be managed independently.

The San Miguel Bay population was only documented in August 2022 following a stranding incident in Calabanga town. Subsequent reconnaissance and boat surveys conducted in 2023 and 2025 recorded only a handful of sightings, indicating a very small population.

“Based on our surveys, sightings remain very few, similar to the other isolated populations,” Aragones said.

Globally, Irrawaddy dolphins (Orcaella brevirostris) are classified as endangered by the International Union for Conservation of Nature (IUCN), but in the Philippines, they are considered critically endangered due to their extremely low numbers.

Aragones presented his findings on May 15 during an event at the Central Bicol State University of Agriculture, emphasizing the ecological importance of the species and the vulnerability of its population in San Miguel Bay.

“I support renewable energy development, especially in the Philippines. However, biodiversity loss—particularly involving a critically endangered species—must never be sacrificed,” he said.

San Miguel Bay has been identified as a priority site for offshore wind development due to its shallow depth, soft seabed, and strong wind potential.

The project, being developed by Nexif Ratch Energy, will cover municipal waters off Calabanga, Tinambac, and Siruma. It is considered among the country’s first large-scale offshore wind farms and is expected to generate jobs, boost local revenues, and reduce carbon emissions by an estimated 1.35 million tons annually.

However, the bay is also a recognized Key Biodiversity Area (KBA) and a major fishing ground supporting thousands of fishers in the Bicol Region. Its rich ecosystem includes mangroves, estuaries, and spawning grounds for commercially important species such as shrimp, crabs, and small pelagic fish.

The presence of Irrawaddy dolphins further underscores the ecological significance of the area. Marine experts consider the species an “indicator species,” meaning its population reflects the overall health of the marine environment.

In August 2022, a female Irrawaddy dolphin measuring 1.8 meters was found dead in Barangay Bonot, Calabanga after being entangled in a crab net—the first recorded sighting of the species in Bicol waters.

The discovery prompted further research by Aragones and his team, in collaboration with the Bureau of Fisheries and Aquatic Resources (BFAR), under a DOST-funded marine mammal monitoring program.

Irrawaddy dolphins are among the most threatened marine mammals in Southeast Asia, inhabiting shallow coastal waters, estuaries, and river systems. In the Philippines, fewer than 100 individuals are believed to remain, mostly concentrated in Malampaya Sound.

Given their slow reproduction rate and sensitivity to human disturbances such as fishing gear entanglement, pollution, and underwater noise, conservationists stress the need to protect their remaining habitats.

San Miguel Bay, which also hosts a 25-hectare fish sanctuary in Tinambac established in 2006, remains a vital ecological and economic resource in the region.

A local fisherman measures a stranded Irrawaddy dolphin found dead in the waters off Barangay Bonot, Calabanga, Camarines Sur on August 16, 2022. (Photo courtesy of BFAR Bicol)