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Utility of rostra in the identification of Australian sawfishes (Chondrichthyes: Pristidae)

Authors

  • Jeff M. Whitty,

    Corresponding author
    1. Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
    • Correspondence to: J. M. Whitty, Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, 6150, Australia.

      Email: jeffmwhitty@hotmail.com

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  • Nicole M. Phillips,

    1. Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
    2. Cooperative Institute for Marine and Atmospheric Studies, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
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  • Dean C. Thorburn,

    1. Indo-Pacific Environmental Pty Ltd, Mt Hawthorn, Western Australia, Australia
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  • Colin A. Simpfendorfer,

    1. Centre for Sustainable Tropical Fisheries and Aquaculture and School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia
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  • Iain Field,

    1. Department of Environment and Geography, Macquarie University, Sydney, New South Wales, Australia
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  • Stirling C. Peverell,

    1. Kooringal, New South Wales, Australia
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  • David L. Morgan

    1. Freshwater Fish Group and Fish Health Unit, School of Veterinary and Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
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ABSTRACT

  1. Effective management of critically endangered sawfishes can be a difficult task, in part due to interspecies misidentification. Current methods for identifying sawfishes can be impractical as they are based on morphological features that are often unobservable. Further exploration is required to develop a more reliable means of identification.
  2. This study explored the utility of sawfish rostra in determining the species, size and sex of sawfishes, as rostra are commonly the only feature of a sawfish observed by fishers or present in public and private collections.
  3. A morphometric and meristic database consisting of over 1100 narrow sawfish (Anoxypristis cuspidata), dwarf sawfish (Pristis clavata), largetooth (or freshwater) sawfish (Pristis pristis; formerly Pristis microdon) and green sawfish (Pristis zijsron) rostra from Australian waters, was statistically analysed.
  4. Identification of sawfishes was found to be possible through the use of the variables: inter-tooth spacing, standard rostrum width/standard rostrum length, standard rostrum length/total rostrum length, rostrum tip width/standard rostrum length, and/or rostral tooth count range, although the distinguishing variables were species-dependent.
  5. The relationship between standard rostrum length and total length was also observed to vary substantially between most species. Models for estimating total length from standard rostrum length are provided.
  6. This study has provided a tool that can be used to identify accurately the species and size of sawfishes by their rostra, and therefore can assist in clarifying historical and contemporary sawfish records, nomenclature and distributions. A better understanding of these issues should allow sawfish conservation strategies to become more focused, and thus more effective.

Copyright © 2013 John Wiley & Sons, Ltd.

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