Understanding The Movements Of Grey Reef Sharks In Tubbataha Reefs Natural Park Using Acoustic Telemetry

Gaining knowledge on the movement and dispersal rates of highly exploited shark species in Marine Protected Areas (MPA) can help to guide and improve their management. Grey reef shark Carcharhinus amblyrhynchos are a... [ view full abstract ]

Gaining knowledge on the movement and dispersal rates of highly exploited shark species in Marine Protected Areas (MPA) can help to guide and improve their management. Grey reef shark Carcharhinus amblyrhynchos are a meso-predatory reef associated species whose ecology is poorly understood within the coral triangle. Acoustic telemetry is a valuable tool for conservation managers as it can quantify the spatial movements and residencies of highly mobile species. Here we used acoustic telemetry to assess the site fidelity and inter-reef connectivity of C. amblyrhynchos in Tubbataha Reefs Natural Park (TRNP), the largest no-take MPA in the Philippines. Seven acoustic receivers were deployed throughout the park between June 2016 and June 2017. Fourteen mature grey reef sharks, seven male and seven female, with total lengths ranging 138-170 cm (x̄ = 153.86 cm, sd = 12.76 cm), were surgically implanted with Vemco acoustic tags over two years. Preliminary data reports residency indexes ranging between 0.14 - 0.69 ( x̄ = 0.37 , sd = 0.28 ) whilst also confirming the movements of C. amblyrhynchos between unconnected reef atolls separated by deep water channels exceeding 1000 m in depth. This study underlines the importance of MPA for shark conservation in the Philippines.