Fine-scale movements of juvenile blacktip reef sharks Carcharhinus melanopterus in a shallow nearshore nursery

George, Lachlan W., Martins, Ana P.B., Heupel, Michelle R., and Simpfendorfer, Colin A. (2019) Fine-scale movements of juvenile blacktip reef sharks Carcharhinus melanopterus in a shallow nearshore nursery. Marine Ecology Progress Series, 623. pp. 85-97.

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View at Publisher Website: https://doi.org/10.3354/meps13010
 
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Abstract

Limited information is available on the fine-scale movements and habitat use of juvenile sharks in very shallow (<1 m) nearshore areas and the factors that drive these behaviours. Active acoustic tracking was used to investigate movements and habitat use of juvenile (683 +/- 58 mm total length; mean +/- SD) blacktip reef sharks Carcharhinus melanopterus at Orpheus Island, Australia. Six juveniles were tracked by foot and boat for over 62 h. Juveniles moved in synchrony with tidal cycles, always remaining within very shallow (<1 m) sandy reef flat or reef crest waters during outgoing, low and incoming tides, and using inundated mangrove habitat during higher tides, indicating that tidal fluctuations were a major driver of movement and habitat use. Individuals never left the bay where they were captured or entered deep water beyond the fringing reef, restricting their movements within water <60 cm deep. In general, linearity and rate of movement were significantly higher during incoming or outgoing tides, whereas these measures were significantly lower during higher tide heights when juveniles were occupying mangrove habitats. The observed behaviour was most likely a predator-avoidance strategy, highlighting the importance of mangrove root habitat use by juvenile blacktip reef sharks in coastal nursery areas and indicating that this may be an essential habitat for the young of this species.

Item ID: 60551
Item Type: Article (Research - C1)
ISSN: 1616-1599
Keywords: Active acoustic telemetry, Fine-scale movements, Nursery area, Predator avoidance, Tidal variation, Habitat use
Funders: James Cook University (JCU), AIMS@JCU
Date Deposited: 09 Oct 2019 07:34
FoR Codes: 06 BIOLOGICAL SCIENCES > 0602 Ecology > 060205 Marine and Estuarine Ecology (incl Marine Ichthyology) @ 70%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 15%
07 AGRICULTURAL AND VETERINARY SCIENCES > 0704 Fisheries Sciences > 070402 Aquatic Ecosystem Studies and Stock Assessment @ 15%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830204 Wild Caught Fin Fish (excl. Tuna) @ 50%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960808 Marine Flora, Fauna and Biodiversity @ 50%
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