Habitat use and spatial segregation of adult spottail sharks Carcharhinus sorrah in tropical nearshore waters

Authors

  • D. M. Knip,

    Corresponding author
    1. Fishing and Fisheries Research Centre, School of Earth and Environmental Sciences, James Cook University, Townsville, Qld 4811, Australia
      Author to whom correspondence should be addressed at present address: Sea Around Us Project, Fisheries Centre, 2202 Main Mall, The University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada. Tel.: +1 778 874 0384; email: d.knip@fisheries.ubc.ca; danielle.knip@my.jcu.edu.au
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  • M. R. Heupel,

    1. Australian Institute of Marine Science and James Cook University, Townsville, Qld 4811, Australia
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  • C. A. Simpfendorfer

    1. Fishing and Fisheries Research Centre, School of Earth and Environmental Sciences, James Cook University, Townsville, Qld 4811, Australia
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Author to whom correspondence should be addressed at present address: Sea Around Us Project, Fisheries Centre, 2202 Main Mall, The University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada. Tel.: +1 778 874 0384; email: d.knip@fisheries.ubc.ca; danielle.knip@my.jcu.edu.au

Abstract

An array of acoustic receivers deployed in Cleveland Bay, north Queensland, Australia, passively tracked 20 adult spottail sharks Carcharhinus sorrah over 2 years (2009–2010) to define patterns in movement and habitat use. Individuals were present in the study site for long periods, ranging from 8 to 408 days (mean = 185). Size and location of home ranges did not vary over time. A high level of segregation occurred among C. sorrah, with individuals using different types of habitat and showing strong attachment to specific regions. The depth of habitat individuals used varied between sexes. Males tended to use a narrow range of habitat depths within the study site (2·8–6·0 m), whereas females used shallower habitats (1·4–6·2 m) and displayed a seasonal shift in the depth of habitat used. Mean monthly habitat depth used varied by as much as 2 m for females, with individuals using shallower habitats during the winter months. Long-term presence and consistent home ranges suggest that Cleveland Bay provides important habitat for C. sorrah. By defining patterns in the use of nearshore habitats for C. sorrah, this study improves the understanding of the movement and habitat use of smaller-bodied coastal sharks and may help provide guidance for the management of their populations.

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