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POPULATION GENETIC STRUCTURE OF COASTAL BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN THE NORTHERN BAHAMAS

Authors

  • Kim M. Parsons,

    1. Lighthouse Field Station, School of Biological Sciences, University of Aberdeen, Cromarty IV11 8YJ, United Kingdom and Bahamas Marine Mammal Survey (BMMS), P. O. Box AB20714, Marsh Harbor, Abaco, The Bahamas E-mail: kim.parsons@noaa.gov
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  • John W. Durban,

    1. Lighthouse Field Station, School of Biological Sciences, University of Aberdeen, Cromarty IV11 8YJ, United Kingdom and Bahamas Marine Mammal Survey (BMMS), P. O. Box AB20714, Marsh Harbor, Abaco, The Bahamas E-mail: kim.parsons@noaa.gov
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  • Diane E. Claridge,

    1. Lighthouse Field Station, School of Biological Sciences, University of Aberdeen, Cromarty IV11 8YJ, United Kingdom and Bahamas Marine Mammal Survey (BMMS), P. O. Box AB20714, Marsh Harbor, Abaco, The Bahamas E-mail: kim.parsons@noaa.gov
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  • Denise L. Herzing,

    1. Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431–0991, U.S.A.
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  • Kenneth C. Balcomb,

    1. Bahamas Marine Mammal Survey (BMMS), P. O. Box AB20714, Marsh Harbor, Abaco, The Bahamas and Center for Whale Research, Smugglers Cove Road, Friday Harbor, Washington 98250, U.S.A.
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  • Les R. Noble

    1. School of Biological Sciences, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 3FX, United Kingdom
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Abstract

Population substructure has important implications for a species' ecology and evolution. As such, knowledge of this structuring is critical for the conservation and management of natural populations. Among marine mammals, many examples exist of species that enjoy a broad geographical distribution, yet are characterized by fine-scale population subdivisions. Coastal bottlenose dolphins have been studied extensively in a few regions globally, and these studies have highlighted a great diversity in both social strategies and demographic isolation. Here we use molecular genetic markers to examine the degree of population subdivision among three study sites separated by less than 250 km on Little Bahama Bank in the northern Bahamas. Mitochondrial DNA (mtDNA) sequence variation and microsatellite genotypes were used to assess partitioning of genetic variance among 56 individually recognized coastal ecotype bottlenose dolphins. Although resolved levels of genetic differentiation suggest gene flow among the three study sites, both nuclear and mitochondrial data indicate a significant degree of subdivision within the Little Bahama Bank population, and sex-based analyses suggest that patterns of dispersal may not be strictly biased toward males. These results corroborate the site fidelity documented through long-term photo-identification studies in the NE Bahamas, and highlight the need to consider independent subpopulation units for the conservation and management of coastal bottlenose dolphins in the Bahamas.

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