Scientists from Large Marine Vertebrates Research Institute Philippines (LAMAVE), Tubbataha Management Office (TMO) and the Marine Megafauna Foundation (MMF) have successfully tagged a 3.5-metre tiger shark and three grey reef sharks as part of a long-term study in Tubbataha Reefs Natural Park.

The research expedition between 22 May and 2 June is the latest in the four years that the organizations have worked together to study the sharks of Tubbataha Reefs Natural Park (TRNP), which has been under protection since 1998 and was declared a UNESCO World Heritage site in 1993. It is now the most successful MPA in the Philippines, and the only place in the nation’s waters where divers can encounter tiger sharks.

The LAMAVE project is the largest current study of sharks around the Philippines, and the tiger shark the largest that they have tagged to date.

The team with one of the acoustic receivers (Photo: Sally Snow/LAMAVE)

According to the IUCN, 25 percent of sharks and rays are threatened with extinction. The research aims to provide understanding as to how different shark species use the TRNP in order to facilitate the design of other MPAs within the Philippines and worldwide.

The team is using acoustic tags, with a battery life of up to 10 years, to understand how grey reef sharks and tiger sharks are using the park, along with satellite tags that track the sharks’ movements outside the park’s boundaries. The tags provide insight as to how the sharks make use of the habitat, creating a map of individual shark movements every time a tagged animal passes within 500m of the 7 receivers that are positioned throughout the park. LAMAVE hopes to expand this network over the coming years to build a larger map of shark movements around the Philippines.

Grey reef sharks are not known to range over long distances, however, tiger sharks are pelagic nomads and will consequently leave the protection of the national park during their lives. The satellite tags communicate with the ARGOS satellite network every time they surface, providing the team with almost real-time data as the sharks navigate through the oceans.

One of the acoustic receivers in the Tubbataha Reefs Natural Park (Photo: Chris Rohner/LAMAVE)

Adapted from divemagazine.co.uk