Clare Prebble, Using biochemical markers to investigate the hidden lives of elasmobranchs
Channel: African Campus
Date: 15/05/2013

Oral Presentation

Clare E.M. Prebble1,2, Simon S.J. Pierce1,2,3, Christoph A. Rohner1,4, David Robinson5, Clive N. Trueman2
1Manta Ray and Whale Shark Research Centre, Marine Megafauna Foundation, Praia do Tofo, Inhambane, Mozambique
2National Oceanography Centre, Southampton, University of Southampton Waterfront Campus, European Way, Southampton SO14 3ZH
3ECOCEAN USA, Praia do Tofo, Inhambane, Mozambique
4Biophysical Oceanography Group, School of Geography, Planning and Environmental Management, University of Queensland, St Lucia QLD 4072, Australia
5Shark Watch Arabia

Whale sharks are the world's largest fish and they aggregate in specific coastal areas exploiting seasonal resources. Whale sharks are wide-ranging and deep-diving, yet despite their large size, and placid disposition little is known about their movements and feeding ecology away from inshore waters.
This project uses stable isotope analysis as a tool to give time integrated information on the assimilated diet of the sharks. Using stable isotopes as a 'biological tag' we examine the movements and trophic ecology of whale sharks at several locations globally. This methodology is a cost effective way to gather information on hundreds of individuals in a non-lethal manner, and within a reasonable time frame.
Here we discuss preliminary results from the first year of data collection at three study sites in the Indian Ocean (Mozambique, Tanzania and Qatar). The results to date focus on the main study site in Tofo, Mozambique where there is long term individual information currently available. We assess the effects of latitude, sex and size on the long-term feeding ecology of whale sharks.
We outline future work and the integration of fatty acid analysis, and electronic tagging to produce a holistic view of whale shark migrations and habitat use.