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This seminar has been cancelled.

CHAIRPERSON

Dr Liz Chee, Asia Research Institute, and Tembusu College, National University of Singapore

ABSTRACT

Pelagic sharks are poorly understood because of limitations inherent in studying them in situ. Knowledge that pelagic thresher sharks (Alopias pelagicus) regularly visit specific locations in the Philippines presented an unique opportunity to study new aspects of their behaviour and biology, and promote their conservation in the region. Post-mortem examinations were conducted on 11 dead A. pelagicus specimens to investigate their ontogenic growth trends, and ectoparasite attachments. Remote and handheld video was used to directly observe pelagic thresher sharks in situ at two sites in the central Visayas. From 239 video observations of pelagic thresher sharks, 117 behaviour events were analysed. 101 individual A. pelagicus were identified by using allometry to non invasively assess shark maturity from video still images, and by tabulating physical characteristics that were unique to each shark. Parasite infestation was a proximate cause for pelagic thresher sharks visiting cleaning stations. A. pelagicus adapted their behaviour in a pose to solicit and facilitate interactions with cleaners that provided them with parasite removal services essential to their health and hygiene. Cleaners foraged selectively on pelagic thresher sharks and fed preferentially on specific ectoparasites that occupied specific sites of a shark’s body. Daily foraging expeditions led pelagic thresher sharks to potentially venture across the jurisdictional waters of five provincial territories. Evidence from the video records confirmed prior speculations that A. pelagicus hunt with their tails. Pelagic thresher sharks used tail-slaps to stun and kill shoaling sardines. The strategy was efficient since A. pelagicus were able to consume more than one prey fish at a time. Understanding new aspects of the behaviour and biology of pelagic thresher sharks led to their legal protection in many parts of the Philippines, and provided insight into managing tourism activities at sites where they forage and clean. Observable behaviours seen at these sites may explain why these mainly oceanic sharks venture into shallow coastal waters where they are vulnerable to anthropogenic disturbance.

ABOUT THE SPEAKER

Simon Oliver is a lecturer in Conservation Biology / Marine Biology at the University of Chester, and the founder of Thresher Shark Research and Conservation Project(TSRCP) in the Philippines. His doctoral work focused on the behaviour, biology, and conservation of pelagic thresher sharks with particular emphasis on their cleaning and hunting strategies. His work has been well recognised in the scientific community (Nature, Science, and Scientific American), and has attracted considerable media attention (BBC, The Guardian, NERC Planet Earth, National Geographic, etc.). TSRCP promotes and disseminates shark research, education and conservation to a broad local, regional, and international public and scientific outreach. The Project hosts volunteers, as well as BSc and MSc students who join its expeditions to assimilate data for their thesis projects. These have enabled Dr Oliver to expand the scope of his research interests to encompass the relevance and impact of conservation on local communities and foster international collaborations. Dr Oliver was recently awarded £500,000 by Discovery Communications to further his research on pelagic thresher sharks in the Philippines. He is currently collaborating with colleagues from Rutgers University Marine Field Station, Ghent University’s Marine Biology Research Group, Singapore Management University, and the Department of Marine Ecology at The University of Liverpool.

REGISTRATION

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