Movement patterns of silvertip sharks (Carcharhinus albimarginatus) on coral reefs

Espinoza, Mario, Heupel, Michelle R., Tobin, Andrew J., and Simpfendorfer, Colin A. (2015) Movement patterns of silvertip sharks (Carcharhinus albimarginatus) on coral reefs. Coral Reefs, 34 (3). pp. 807-821.

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Abstract

Understanding how sharks use coral reefs is essential for assessing risk of exposure to fisheries, habitat loss, and climate change. Despite a wide Indo-Pacific distribution, little is known about the spatial ecology of silvertip sharks (Carcharhinus albimarginatus), compromising the ability to effectively manage their populations. We examined the residency and movements of silvertip sharks in the central Great Barrier Reef (GBR). An array of 56 VR2W acoustic receivers was used to monitor shark movements on 17 semi-isolated reefs. Twenty-seven individuals tagged with acoustic transmitters were monitored from 70 to 731 d. Residency index to the study site ranged from 0.05 to 0.97, with a mean residency (+/- SD) of 0.57 +/- 0.26, but most individuals were detected at or near their tagging reef. Clear seasonal patterns were apparent, with fewer individuals detected between September and February. A large proportion of the tagged population (> 71 %) moved regularly between reefs. Silvertip sharks were detected less during daytime and exhibited a strong diel pattern in depth use, which may be a strategy for optimizing energetic budgets and foraging opportunities. This study provides the first detailed examination of the spatial ecology and behavior of silvertip sharks on coral reefs. Silvertip sharks remained resident at coral reef habitats over long periods, but our results also suggest this species may have more complex movement patterns and use larger areas of the GBR than common reef shark species. Our findings highlight the need to further understand the movement ecology of silvertip sharks at different spatial and temporal scales, which is critical for developing effective management approaches.

Item ID: 41783
Item Type: Article (Research - C1)
ISSN: 1432-0975
Keywords: coral reefs, predator, behavior, acoustic telemetry, sharks, conservation
Funders: National Environmental Research Program (NERP), Australian Research Council (ARC), PADI Foundation, Australian Endeavour Program, AIMS@JCU
Projects and Grants: NERP Tropical Ecosystems Hub Project 6.1, ARC Future Fellowship project #FT100101004
Date Deposited: 08 Dec 2015 17:23
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 60%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070402 Aquatic Ecosystem Studies and Stock Assessment @ 40%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830204 Wild Caught Fin Fish (excl. Tuna) @ 40%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960507 Ecosystem Assessment and Management of Marine Environments @ 60%
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