ESR 24:45-60 (2014)  -  DOI: https://doi.org/10.3354/esr00580

Genetic structure and diversity of two highly vulnerable carcharhinids in Australian waters

Pascal T. Geraghty1,2,*, Jane E. Williamson1, William G. Macbeth2, Dean C. Blower3, Jess A. T. Morgan4, Grant Johnson5, Jennifer R. Ovenden3, Michael R. Gillings1

1Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia
2NSW Department of Primary Industries, Cronulla Fisheries Research Centre of Excellence, PO Box 21, Cronulla, NSW 2230, Australia
3Molecular Fisheries Laboratory, The University of Queensland, St. Lucia, QLD 4072, Australia
4Queensland Alliance for Agriculture & Food Innovation, Centre for Animal Science, PO Box 6097, The University of Queensland, St. Lucia, QLD 4067, Australia
5Northern Territory Department of Primary Industry and Fisheries, GPO Box 3000, Darwin, NT 0801, Australia

ABSTRACT: Molecular techniques were employed to investigate genetic structure and diversity in dusky Carcharhinus obscurus and sandbar C. plumbeus sharks in the Indo-Australian region. Tissue samples of 423 C. obscurus and 442 C. plumbeus defined 18 and 11 mtDNA ND4 haplotypes, respectively. For C. obscurus, weak genetic differentiation was detected between eastern and western Australian waters (pairwise ΦST = 0.04437, p < 0.008; pairwise FST = 0.02403, p < 0.035), suggesting the delineation of 2 independent populations, while patterns of gene flow between Australia and Indonesia were inconclusive. Rarefaction analysis, however, indicated that robust population comparisons in these species were reliant on sample numbers >100 at any particular location. Off Australia‚Äôs temperate east coast, C. obscurus and C. plumbeus exhibited strong similarities in genetic structure, suggestive of similar evolutionary histories in the region. In addition, genetic validation revealed observers to be highly accurate in the identification of both target species in an eastern Australian shark fishery. Our findings contribute valuable information for the management and conservation of both species.


KEY WORDS: Carcharhinidae · Fisheries management · Indo-Pacific · Mitochondrial DNA ·  Observer accuracy · Population genetics · Stock structure


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Cite this article as: Geraghty PT, Williamson JE, Macbeth WG, Blower DC and others (2014) Genetic structure and diversity of two highly vulnerable carcharhinids in Australian waters. Endang Species Res 24:45-60. https://doi.org/10.3354/esr00580

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