How large is the world's largest fish? Measuring whale sharks Rhincodon typus with laser photogrammetry

Authors

  • C. A. Rohner,

    Corresponding author
    1. Marine Megafauna Foundation, Praia do Tofo, Mozambique
    2. Centre for Spatial Environmental Research, The University of Queensland, St Lucia QLD 4072, Australia
    3. CSIRO Marine and Atmospheric Research, Cleveland QLD 4163, Australia
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  • A. J. Richardson,

    1. CSIRO Marine and Atmospheric Research, Cleveland QLD 4163, Australia
    2. Centre for Applications in Natural Resource Mathematics (CARM), The University of Queensland, St Lucia QLD 4072, Australia
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  • A. D. Marshall,

    1. Marine Megafauna Foundation, Praia do Tofo, Mozambique
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  • S. J. Weeks,

    1. Centre for Spatial Environmental Research, The University of Queensland, St Lucia QLD 4072, Australia
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  • S. J. Pierce

    1. All Out Africa Research Unit, P. O. Box 153, Lobamba, Swaziland
    2. Eyes on the Horizon, Praia do Tofo, Mozambique
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Tel.: +61 7 3365 1475; email: c.rohner1@uq.edu.au

Abstract

Laser photogrammetry was found to be a promising new cost-effective technique for measuring free-swimming whale sharks Rhincodon typus. Photogrammetric measurements were more precise than visual size estimates by experienced researchers, with results from the two methods differing by 9· 8 ± 1· 1% (mean ±s.e.). A new metric of total length and the length between the fifth gill and first dorsal fin (r2 = 0· 93) is proposed to facilitate easy, accurate length measurements of whale sharks in the field.

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