Reproductive biology of Zearaja chilensis (Chondrichthyes: Rajidae) in the south-east Pacific Ocean

Authors

  • C. Bustamante,

    Corresponding author
    1. School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia
    2. Laboratorio de Elasmobranquios (ELASMOLAB), Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
      Tel.: +61 7 33467975; email: carlos.bustamantediaz@uqconnect.edu.au
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  • C. Vargas-Caro,

    1. Laboratorio de Elasmobranquios (ELASMOLAB), Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
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  • M. C. Oddone,

    1. Universidade Federal de Rio Grande, Instituto de Oceanografia, Laboratório de Histologia, Instituto de Ciências Biológicas, Avenida Itália, km 8 s/n, Caixa Postal 474, 96201-900, Rio Grande, RS, Brazil
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  • F. Concha,

    1. Laboratorio de Ecología e Impactos Ambientales, Facultad de Ciencias del Mar y de Recursos Naturales, Universidad de Valparaíso, Chile
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  • H. Flores,

    1. Laboratorio de Elasmobranquios (ELASMOLAB), Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
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  • J. Lamilla,

    1. Laboratorio de Elasmobranquios (ELASMOLAB), Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
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  • M. B. Bennett

    1. School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia
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Tel.: +61 7 33467975; email: carlos.bustamantediaz@uqconnect.edu.au

Abstract

Between 2000 and 2002, three artisanal landing sites were sampled in southern Chile, with data on population structure and reproductive development collected from 5477 yellownose skates Zearaja chilensis. Total length (LT) ranged from 33 to 158 cm for females and 34 to 155 cm for males. No sexual dimorphism was evident in disc size (length or width) or in LT– mass relationships. The smallest mature female was 95 cm LT and the size at which 50% were mature (LT50) was 109 cm. Males matured between 80 and 90 cm LT with a LT50 of 88 cm. Although the largest Z. chilensis captured by the artisanal fishery was 155 cm LT, 89% of landings comprised relatively small, immature fish. This situation may compromise the stock integrity if intrinsic vulnerability and probable long-life span of Z. chilensis are considered. Consequences for the survival of the species and possible signs of a fishery collapse must be reviewed by management authorities by consideration of both artisanal and industrial landings in Chile.

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