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RESEARCH ARTICLE
Contents Vol 58(7)

Habitat type promotes rapid and extremely localised genetic differentiation in dolphins

Luciana M. Möller A B C , Joanna Wiszniewski A B , Simon J. Allen A and Luciano B. Beheregaray B
+ Author Affiliations
- Author Affiliations

A Marine Mammal Research Group, Graduate School of the Environment, Macquarie University, NSW 2109, Australia.

B Molecular Ecology Group for Marine Research, Department of Biological Sciences, Macquarie University, NSW 2109, Australia.

C Corresponding author. Email: luciana.moller@gse.mq.edu.au

Marine and Freshwater Research 58(7) 640-648 https://doi.org/10.1071/MF06218
Submitted: 20 November 2006  Accepted: 21 May 2007   Published: 27 July 2007

Abstract

The high potential for dispersal of many marine organisms often results in low population differentiation over large distances. Here, we report that dolphin communities living in very close geographic proximity (<16 km) but in two different environments – open coast and enclosed embayment – exhibit unexpected genetic differentiation at nine microsatellite loci. Results based on a fixation index and a Bayesian clustering approach suggested that gene flow between communities within an embayment is high, as is gene flow between coastal communities. However, lower gene flow between embayment and open coast communities translated into substantial genetic differentiation between dolphin communities from the two environments, and assignment of individuals into two populations. Along with patterns observed in 403 bp of the mitochondrial DNA control region, the results suggest that restriction of gene flow likely occurred in the last 6000 years, after coastal dolphins colonised the embayment. We hypothesise that factors such as fidelity to the local area and resource and behavioural specialisations may have played a major role in promoting and maintaining genetic subdivision between dolphins of the two environments. Importantly, our study shows that habitat type can rapidly promote extremely fine-scale genetic structure in a long-lived, highly mobile marine mammal.

Additional keywords: dispersal, Indo–Pacific bottlenose dolphin, phylogeography, population genetics, Tursiops aduncus.


Acknowledgements

Financial support was provided by Macquarie University. We thank O. and L. Griffiths for fieldwork support. J. Powell, A. Caccone, F. Balloux and P. Sunnucks provided comments on an earlier draft of the manuscript. This work was conducted under licence from the NSW Department of Environment and Conservation and approved by the Macquarie University Animal Ethics Committee.


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Appendix 1. Allelic frequencies for each bottlenose dolphin community at nine microsatellite loci and number of individuals genotyped at each locus
Alleles private to the coastal* and embayment** communities
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