Based on previous studies by marine researchers, a team of biologists hypothesized that Chironex yamaguchii, a dangerous species of box jellyfish known from Japan, is also present in Philippine waters. This box jellyfish was found to cause severe stings and even fatalities in the Indo-Pacific and Western Pacific regions. Their tentacles can inflict extreme pain, cause skin injuries with welts, and even trigger heart attacks and death.

By closely examining the physical characteristics and DNA of this deadly jellyfish, the team found strong evidence that the species exists in the Coral Triangle, a marine biodiversity hotspot that includes the Philippines. Despite their nearly identical physical characteristics, the scientists discovered small genetic differences between the Philippine and Japanese C. yamaguchii, suggesting that the Philippine C. yamaguchii may be a separate species requiring further research.

The international research team was composed of Dr. Sheldon Rey Boco, Christine Gloria Grace Capidos and Dennis Talacay of The Philippine Jellyfish Stings Project together with Raffy Jay Fornillos and Dr. Ian Kendrich Fontanilla of the University of the Philippines – Diliman College of Science’s Institute of Biology, Dr. Phuping Sucharitakul and Dr. Jonathan Lawley of Griffith University’s School of Environment and Science in Queensland, Australia; Dr. Allen Collins of Smithsonian National Museum of Natural History in Washington, DC; Joseph Elliz Comendador of National Museum of Natural History of the National Museum of the Philippines; and Facundo Rey Ladiao of Leyte Normal University.

“This study shows genetic differences within C. yamaguchii that we couldn’t see just by looking at them as physical specimens,” the researchers explained. “This finding highlights how important it is to use molecular methods to correctly identify species and understand their genetic variety.”

The study’s findings exceeded the team’s expectations, particularly regarding their hypothesis on the species’ presence in the Philippines. “We identified the Philippine population as a potential cryptic species. This means that we are being encouraged to determine if they belong to a new species or if their geographic isolation doesn’t make them entirely distinct from the Japanese population,” the researchers said.

The team added that the citizens and tourists of the coastal communities they visited played a significant role in the research. Their images and videos of box jellyfishes, as well as their traditional knowledge of the marine environment, helped confirm that C. yamaguchii is widespread in Philippine waters. “Their insights and experiences have helped us identify and confirm the presence of the box jellyfish in areas that might otherwise be overlooked. This collaboration between scientists and Filipinos or tourists (“the citizens”) highlights the importance of community involvement in scientific research,” they shared.

“Knowing the genetic diversity and distribution of C. yamaguchii helps in correctly identifying the jellyfish responsible for stings, which is crucial for effective treatment and management,” the biologists added. “Understanding the presence of jellyfish populations in various regions can also help assess the risk of jellyfish stings in those areas, which can protect local communities and tourists.”