research

The Pelagic thresher shark (Alopias pelagicus) is an oceanic species whose biology and behavioural ecology are largely unknown due to study limitations. Fisheries and by-catch data indicate that it is found in warm and temperate offshore waters, that it matures late, has low fecundity and is vulnerable to over-exploitation. International conventions have recognized some shark species to be ‘threatened’, promoting nations to implement protection policy, but species listed comprise those which have received comprehensive scientific investigation, and whose biology and behavioural ecology are well understood. Knowledge that Pelagic thresher sharks regularly visit a seamount in the Philippines presents an unique opportunity to study this rarely observed oceanic shark. Preliminary investigations at this site during 2005 identified significant relationships between shark presence and cleaning activity conducted by resident Cleaner and Moon wrasses (Labriodes dimidiatus and Thalassoma lunare). Cleaning activity relating to sharks has never been investigated in the wild before, but the observable interactions seen at this site explain why these mainly oceanic sharks venture into shallow coastal waters, where they are vulnerable to fishing and disturbance from dive tourism. Understanding their behavioural ecology will provide important information to aid initiatives to protect them.

Monad Shoal is located within the Visayan Sea, 8.16 km due east from the southern beach on Malapascua Island, Cebu, the Philippines. The seamount is an open water site rising 250 meters from the sea floor to 15 - 25 meter depths. Early morning presence of Pelagic thresher sharks on the shoal drives the local dive and tourism industries, fuelling 80% of the regional economy.

AIMS

To investigate the behaviour of Pelagic thresher sharks in response to resident cleaner fishes on Monad Shoal, the Philippines.

To investigate correlations between parasite presence and injury on Pelagic thresher shark individuals to their respective cleaning interactions.

To improve established methods of observing the behaviour of sharks in situ.

To assess the population dynamics of Pelagic thresher shark visit frequency.

To inform conservation initiatives to manage fisheries and dive tourism in relation to their relative impacts on the abundance of Pelagic thresher sharks in the area.

HYPOTHESIS

Individual Pelagic thresher sharks make regular visits inshore to a shallow seamount for cleaning by Cleaner and Moon wrasses where they are incidentally affected by dive tourism and vulnerable to over-exploitation by fisheries.

OBJECTIVES

Identify and map the presence of ectoparasites on Pelagic thresher sharks.

Design photographic ethograms for thresher shark and cleaner wrasse interactions to investigate behavioural patterns.

Examine spatial and temporal (seasonal) distributions of cleaning stations, cleaner fishes and Pelagic thresher sharks in relation to each other.

Identify individual sharks to assess population structure and visit frequency.

Develop a model for managing Monad Shoal as a protected area for Pelagic thresher sharks.

BACKGROUND & RATIONALE

PUBLICATIONS

Oliver S. P., Hussey N. E., Turner J. R., Beckett A. J., Oceanic Sharks Clean at Coastal Seamount. Plos ONE 2010; Resubmitted, publication pending.

Oliver S. P., 2006. The Behaviour of Pelagic Thresher Sharks (Alopias pelagicus) in Relation to Cleaner Fishes (Labroides dimidiatus & Thalassoma lunare) on Monad Shoal, Malapascua Island, Cebu, The Philippines. University of Wales MSc thesis, 2006.

AWARDS and GRANTS

Fugro - GEOS for Marine Science and Technology (Postgraduate Category)

Best Independent Research Project UK 2006

Natural Environment Research Council (NERC) UK

PhD Algorithm Studentship 2007 - 2011

European Social Fund (ESF)

MSc. Studentship 2004 - 2005

ACADEMIC PROJECTS

The distribution, biology and behaviour of thresher sharks (Alopias spp.) in response to cleaning, anthropogenic pressures and conservation solutions in Philippine waters.

University of Wales, Bangor; PhD, 2007 - 2011.

The behaviour of Pelagic thresher sharks (Alopias pelagicus) in relation to cleaner fishes (Labroides dimidiatus & Thalassoma lunare) on Monad Shoal, Malapascua Island, Cebu, the Philippines.

University of Wales, Bangor; MSc thesis, 2006.

The behaviour of Manta rays (Manta birostris) in response to cleaner fishes (Labroides dimidiatus & Thalassoma lunare) on Monad Shoal, Malapascua Island, Cebu, The Philippines.

University of Wales, Bangor; MSc thesis, 2008.

Body region selection and behavioural patterns exhibited by the sharksucker (Echeneis naucrates) on Blacktip (Chacharhinus limbatus) and Tiger (Galeocerdo cuvier) sharks.

University of Wales, Bangor; MSc thesis, 2007.

The effects of SCUBA diving on coral reefs and critical marine habitats.

Barry University, Miami Shores; BSc thesis, 2008.

Topographical characterisation of elasmobranch cleaning stations.

Bay of Plenty Polytechnic, Tauranga; Paper project, 2008.