Scientists in the Philippines tag the biggest tiger shark so far
Puerto Princesa, Philippines, June 22, 2018 – Scientists from Large Marine Vertebrates Research Institute Philippines (LAMAVE), Tubbataha Management Office (TMO) and Marine Megafauna Foundation (MMF) have successfully tagged a 3.5-meter tiger shark and three grey reef sharks as part of a long-term study in Tubbataha Reefs Natural Park.
The research expedition, that took place between the 22nd of May and the 2nd of June, is the fourth year of collaboration between LAMAVE and TMO to study the sharks of Tubbataha Reefs Natural Park (TRNP).
The Park has been protected since 1988 and was declared a UNESCO World Heritage site in 1993. Today it is the Philippines’ most successful marine protected area and was named one of the best- managed MPAs in the world in 2017. It hosts one of the highest number of reef sharks in the world; it is also the only place divers can encounter tiger sharks in the Philippines.
Alarmingly 25% of sharks and rays are threatened with extinction according to the IUCN. The Philippines, which lies at the heart of the Coral Triangle, is a biodiversity hotspot and consequently a crucial area for shark conservation. Understanding how different shark species are using TRNP and why the park is so successful for sharks will be fundamental for helping design and zone other marine protected areas for sharks within the country and worldwide.
The team is using acoustic tags to understand how grey reef sharks and tiger sharks are using the park, as well as satellite tags to track tiger shark movements outside the boundaries of the park.
Acoustic tags provide an insight into habitat use, across space and time. The tags which have up to 10 years’ battery life work by communicating with acoustic receivers positioned around the park. When a tagged shark swims within 500 meters of a receiver a signal is transmitted and recorded. Over time these signals create a map of an individual shark’s movements and presence within the park. There are currently seven receivers positioned in Tubbataha Reefs Natural Park that are picking up signals from tagged animals. With time, LAMAVE plans to expand this network across the Philippines to build a larger map of shark movements within the country.
Grey reef sharks are not known for making large-scale movements and may be staying within the park boundaries. Tiger sharks, on the other hand, are known to make large-scale movements, and consequently may not benefit from the park’s protection throughout their lives. To track tiger sharks beyond the range of the acoustic receivers the team are fitting tiger sharks with satellite tags as well as acoustic tags. Satellite tags communicate with passing ARGOS satellites when the shark breaks the surface and will provide the team with almost real-time movements of the shark, both within and outside the park boundaries. Meanwhile, the acoustic tag will interact with acoustic receivers positioned around the park, revealing both how and where the tiger sharks are spending their time.
To date, the study is the largest research project on sharks in the Philippines. Thanks to all parties involved that made this research possible.
A Press Release of this story is available HERE.