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A new metric for measuring condition in large predatory sharks

Authors

  • D. J. Irschick,

    Corresponding author
    1. Department of Biology, 221 Morrill Science Center, University of Massachusetts at Amherst, Amherst, MA, U.S.A.
    2. Organismic and Evolutionary Biology Program, University of Massachusetts Amherst, Amherst, MA, U.S.A.
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  • N. Hammerschlag

    1. Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149-1098, U.S.A.
    2. Leonard and Jayne Abess Center for Ecosystem Science and Policy, University of Miami, Coral Gables, FL 33146, U.S.A.
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Abstract

A simple metric (span condition analysis; SCA) is presented for quantifying the condition of sharks based on four measurements of body girth relative to body length. Data on 104 live sharks from four species that vary in body form, behaviour and habitat use (Carcharhinus leucas, Carcharhinus limbatus, Ginglymostoma cirratum and Galeocerdo cuvier) are given. Condition shows similar levels of variability among individuals within each species. Carcharhinus leucas showed a positive relationship between condition and body size, whereas the other three species showed no relationship. There was little evidence for strong differences in condition between males and females, although more male sharks are needed for some species (e.g. G. cuvier) to verify this finding. SCA is potentially viable for other large marine or terrestrial animals that are captured live and then released.

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