Study examines where and when marine mammals were stranded in the Philippines over an 18-year period

15 May 2026

When marine mammals become stranded, these events can provide important information about their health, population changes, biodiversity, and where they are found. They can also help scientists better understand the overall condition and health of the ocean.

This study looked at the strandings of marine mammals in the Philippines over 18 years from 2005 to 2022, following up on an earlier study from 1998 to 2009. It focused on understanding where and when these strandings happen, which species frequently strand, and how this information can help with conservation efforts.

The study showed a total of 1,368 stranding events, averaging 76 per year, with some fluctuations over time. Of the 30 marine mammal species in the Philippines, 27 species have stranded along the coasts. The most common stranders are the spinner dolphins, dugong, Risso’s dolphin, Fraser’s dolphins, and melon-headed whales. Most strandings involved a single animal, and more than half of them were alive when found. The study further identified certain areas or hotspots along the Philippine coastline, found mostly in Luzon, where strandings occur more frequently. It also investigated the timing of stranding events and found peaks in certain species during specific months, such as March to May for spinner dolphins, Risso’s dolphins, and melon-headed whales.

The results of the study highlighted the importance of long-term data for tracking marine mammal stranding events and understanding the factors influencing these strandings. It also showed how human activities like fishing and illegal practices, along with natural factors, such as seasonal changes, contribute to strandings. Moreover, strandings can serve as an indicator of the health of marine mammal populations, particularly for vulnerable species like the Irrawaddy dolphins and dugongs. This information is vital for monitoring strandings and generating relevant information essential for marine mammal conservation. All in all, the findings are important for creating strategies to protect and conserve marine mammals in the region.

Authors: Lemnuel V. Aragones (Institute of Environmental Science & Meteorology (IESM), College of Science (CS), University of the Philippines (UP) Diliman | Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman), Alessandra Nicole L. Morado (IESM, CS, UP Diliman | Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman), Marie Christine M. Obusan (Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman | Institute of Biology, CS, UP Diliman), Honey Leen M. Laggui (IESM, CS, UP Diliman | Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman), Jonah L. Bondoc (Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman | Natural Sciences Research Institute, CS, UP Diliman), Leo Jonathan A. Suarez (Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman | Ocean Adventure, Ilanin Forest West, Subic Bay Freeport), and Ewen Kye Lawler (Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra)

Read the full paper: http://dx.doi.org/10.1578/AM.50.4.2024.302

Study examines where and when marine mammals were stranded in the Philippines over an 18-year period

When marine mammals become stranded, these events can provide important information about their health, population changes, biodiversity, and where they are found. They can also help scientists better understand the overall condition and health of the ocean.

This study looked at the strandings of marine mammals in the Philippines over 18 years from 2005 to 2022, following up on an earlier study from 1998 to 2009. It focused on understanding where and when these strandings happen, which species frequently strand, and how this information can help with conservation efforts.

The study showed a total of 1,368 stranding events, averaging 76 per year, with some fluctuations over time. Of the 30 marine mammal species in the Philippines, 27 species have stranded along the coasts. The most common stranders are the spinner dolphins, dugong, Risso’s dolphin, Fraser’s dolphins, and melon-headed whales. Most strandings involved a single animal, and more than half of them were alive when found. The study further identified certain areas or hotspots along the Philippine coastline, found mostly in Luzon, where strandings occur more frequently. It also investigated the timing of stranding events and found peaks in certain species during specific months, such as March to May for spinner dolphins, Risso’s dolphins, and melon-headed whales.

The results of the study highlighted the importance of long-term data for tracking marine mammal stranding events and understanding the factors influencing these strandings. It also showed how human activities like fishing and illegal practices, along with natural factors, such as seasonal changes, contribute to strandings. Moreover, strandings can serve as an indicator of the health of marine mammal populations, particularly for vulnerable species like the Irrawaddy dolphins and dugongs. This information is vital for monitoring strandings and generating relevant information essential for marine mammal conservation. All in all, the findings are important for creating strategies to protect and conserve marine mammals in the region.

Authors: Lemnuel V. Aragones (Institute of Environmental Science & Meteorology (IESM), College of Science (CS), University of the Philippines (UP) Diliman | Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman), Alessandra Nicole L. Morado (IESM, CS, UP Diliman | Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman), Marie Christine M. Obusan (Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman | Institute of Biology, CS, UP Diliman), Honey Leen M. Laggui (IESM, CS, UP Diliman | Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman), Jonah L. Bondoc (Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman | Natural Sciences Research Institute, CS, UP Diliman), Leo Jonathan A. Suarez (Philippine Marine Mammal Stranding Network Inc., IESM, CS, UP Diliman | Ocean Adventure, Ilanin Forest West, Subic Bay Freeport), and Ewen Kye Lawler (Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra)

Read the full paper: http://dx.doi.org/10.1578/AM.50.4.2024.302