DNA barcoding reveals overlooked marine fishes

Authors

  • TYLER S. ZEMLAK,

    1. Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, University of Guelph, 579 Gordon Street, Guelph, ON, Canada N1G 2W1,
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    • §

      Present address: Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada B3H 4J1.

  • ROBERT D. WARD,

    1. CSIRO Wealth from Oceans Flagship, CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, Tas 7001, Australia,
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  • ALLAN D. CONNELL,

    1. South African Institute of Aquatic Biodiversity, Private Bag 1015, Grahamstown 6140, South Africa
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  • BRONWYN H. HOLMES,

    1. CSIRO Wealth from Oceans Flagship, CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart, Tas 7001, Australia,
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  • PAUL D. N. HEBERT

    1. Canadian Centre for DNA Barcoding, Biodiversity Institute of Ontario, University of Guelph, 579 Gordon Street, Guelph, ON, Canada N1G 2W1,
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P. D. N. Hebert, Fax: 519-824-5703; E-mail: phebert@uoguelph.ca

Abstract

With more than 15 000 described marine species, fishes are a conspicuous, diverse and increasingly threatened component of marine life. It is generally accepted that most large-bodied fishes have been described, but this conclusion presumes that current taxonomic systems are robust. DNA barcoding, the analysis of a standardized region of the cytochrome c oxidase 1 gene (COI), was used to examine patterns of sequence divergence between populations of 35 fish species from opposite sides of the Indian Ocean, chosen to represent differing lifestyles from inshore to offshore. A substantial proportion of inshore species showed deep divergences between populations from South African and Australian waters (mean = 5.10%), a pattern which also emerged in a few inshore/offshore species (mean = 0.84%), but not within strictly offshore species (mean = 0.26%). Such deep divergences, detected within certain inshore and inshore/offshore taxa, are typical of divergences between congeneric species rather than between populations of a single species, suggesting that current taxonomic systems substantially underestimate species diversity. We estimate that about one third of the 1000 fish species thought to bridge South African and Australian waters actually represent two taxa.

Ancillary