Malapascua Island is almost synonymous to thresher sharks, not to mention the pristine white beaches, generally this pelagic drives the local dive and tourism industries, fuelling 80% of the regional economy. Myself included was first drawn to this southernmost tip island of Cebu province almost three years now, aiming to catch glimpse of the phenomenal presence of the shark in shallow waters.
This pelagic thresher Shark (Alopias Pelagicus) is an oceanic species whose biology and behavioral ecology are largely unknown due to study limitations. Fisheries and by-catch data indicate that it is found in warm and temperate offshore waters, matures late, has low fecundity and is vulnerable to over-exploitation. International conventions have recognized almost all shark species to be threatened, promoting nations to implement protection policies. These listed species comprise those which have received comprehensive scientific investigation, and whose biology and behavioral ecology are well understood. The fact that thresher sharks regularly visit a sea mount in the Philippines presents a unique opportunity to study this rarely observed oceanic shark. Preliminary investigations of the site identified significant relationships between shark presence and cleaning activity conducted by resident Cleaner and Moon wrasses (Labriodes Dinidiatus and Thalassoma Lunare). Cleaning activity relating to sharks has never been investigated in the wild before, but this observable interactions seen at this site explained why these mainly oceanic sharks venture into shallow coastal waters, where they are vulnerable to fishing and disturbance from dive tourism. Understanding their behavioral ecology will provide important information to support the protection plan for the specie.
Monad Shoal is located within the Visayan Sea, 8.16 km due east from the southern beach of Malapascua Island. The sea mount is an open water site rising 250 meters from the sea floor to 15=25 meter depths. Early morning presence of thresher sharks on the shoal attracted local dive and tourism industries to Malapascua Island.
It is with these facts and reasons that the Thresher Shark Research Conservation Project initiated, it started in 2009. The project aimed to investigate the behavior of thresher sharks in response to resident cleaner fishes, the correlations between parasite presence, to improve established methods of observing the specie, to assess also the population dynamics of visit frequency, and to provide relevant information to conservation initiatives in relation to managing impacts of fishery and dive tourism. The project is developing a model for managing Monad Shoal as a protected area for the thresher sharks.
Please visit www.threshersharkproject.org for more details. You could be part of this research conservation project.