Limited latitudinal ranging of juvenile whale sharks in the Western Indian Ocean suggests the existence of regional management units

Clare E. M. Prebble, Christoph A. Rohner, Simon J. Pierce, David P. Robinson, Mohammed Y. Jaidah, Steffen S. Bach, Clive N. Trueman

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Assessing the movements and connectivity of whale sharks Rhincodon typus through their range is difficult due to high individual mobility and limited knowledge of their behaviour following dispersal from coastal aggregation sites. Here, we use a large set of photo-identification and stable isotope data (δ15N and δ13C) to test the assumption that sharks frequenting aggregation sites in Mozambique, Tanzania, and Qatar are a mixed stock, as inferred by genetic data. Photo-identification revealed negligible connectivity among aggregation sites and none between the southern and central areas of the Western Indian Ocean (Mozambique and Tanzania) and the Arabian Gulf (Qatar). Sight−resight data indicated that shark movements at each site could be best represented by a model that included emigration, re-immigration, and some mortality or permanent emigration. Although there was high individual variation in the isotope profiles of sharks from each location, comparison with latitudinal isotope data suggests that sharks had shown site fidelity to within a few hundred kilometres of each study area over the period of isotopic integration. Given the Endangered status of whale sharks and regional differences in anthropogenic threat profiles, further studies — and conservation assessment efforts — should consider the possibility that whale shark subpopulations exist over smaller geographical scales than previously documented.
Original languageEnglish (US)
Pages (from-to)167-183
Number of pages17
JournalMARINE ECOLOGY PROGRESS SERIES
Volume601
DOIs
StatePublished - Aug 9 2018
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2022-06-03
Acknowledgements: We thank everyone at the Marine Megafauna Foundation and the whale shark research team at King Abdullah University of Science and Technology, and the Tanzanian Fisheries Institute for carrying out fieldwork and contributing to both the photo-ID data and sample collection. We thank everyone involved in the Qatar Whale Shark Research Project, as well as the staff at the Qatar Ministry of Municipality and Environment (QMME), and the Qatar Coast Guard for providing the platform to carry out field research in Qatar. We thank the North Oil Company in Qatar for their support and for joining the Qatar Whale Shark Research project as the new operator of the Al Shaheen oil field. We also thank the World Wide Fund for Nature Tanzania, Shark Foundation, Aqua-Firma, Rufford Small Grants, Waterlust, and the PADI Foundation, for their support of this project. Special personal thanks to Baraka Kuguru and Mathias Igulu for their help with Tanzanian permits, Jason Rubens and Haji Machano for facilitating the project, and Liberatus Mokoki for his expertise on the water. S.J.P. and C.A.R. were supported by 2 private trusts. In Mozambique we also thank Peri-Peri Divers and Casa Barry Lodge for providing logistical support and All Out Africa and Underwater Africa for contributing to the photo-ID data. We thank Dr. Peter Corkeron and the 2 anonymous reviewers for their helpful comments.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • Ecology
  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science

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