As part of the research project called ‘Expedition Shark’, the Tubbataha Management Office (TMO) and Large Marine Vertebrates Research Institute Philippines (LAMAVE) recently completed the first ‘shark-tagging’ activity in the country. Nine grey reef sharks and one tiger shark found in Tubbataha Reefs Natural Park were fitted with ‘acoustic tags’ to track the animals’ movement in the water and provide significant insights to researchers regarding their behavior, said TMO’s park manager Angelique Songco.
The activity is part of on-going work to study the population of sharks and rays in the UNESCO World Heritage Site and largest no-take marine protected area in the country.
“Konti lang kasi ang kaalaman ng tao sa mga shark, so kung hindi mo naiintindihan ang isang species, hindi mo alam kung paano ima-manage, hindi mo ma-conserve,” Songco explained, adding that the study can be used as basis for future legislations on marine resources conservation in the country.
LAMAVE Executive Director Alessandro Ponzo emphasized that understanding the movement of sharks is a step towards effectively protecting them. In the case of the tiger shark, Ponzo continued, the transmissions from the satellite tag will show them if the shark is staying within the park or moving outside the boundaries. Information on such behavior will help the researchers in planning steps towards better protecting areas that are important to the species.
“Sharks are disappearing fast from all the world’s oceans so understanding the behavior of those that are left is crucial if we hope to manage ecosystems effectively and repopulate shark populations,” Ponzo underscored.
According to the researchers, the acoustic tags fitted to the sharks are able to interact with acoustic receivers (waterproof listening devices) that pick up and record individual signals from the tags as the shark swim by. The receivers can pick up signals within an 800-meter range, and a total of seven receivers have been positioned underwater across the natural park. The team has also tagged two Reef Mantas (Manta alfredi) with acoustic tags. Both individuals have been spotted in the park in 2016 and by fitting a tag, the team hope to understand how they too are using the protected area.
‘Expedition Shark’ marks the third year of collaboration between LAMAVE and TMO. In 2015, the first expedition focused on tagging whale sharks to track their movement outside the park. Last year, the team fitted the first tiger shark in the Coral Triangle with a satellite tag, and four grey reef sharks with acoustic tags. The team will expand the acoustic network later this year by deploying receivers in the waters of Cagayancillo, an archipelagic municipality located around 130km northeast of the Tubbataha Reefs Natural Park.