Fine-scale genetic structure of bottlenose dolphins, Tursiops truncatus, in Atlantic coastal waters of the Iberian Peninsula

Abstract

In the NE Atlantic, evidence has been found of genetic discontinuities between Iberian bottlenose dolphins and those of Scotland and the Mediterranean. Here, we explored the genetic relationships between resident populations of dolphins from southern Galicia (NW Spain) and the Sado estuary (S Portugal), and their relationship with dolphins inhabiting neighbouring areas. A total of 91 skin and muscle samples were taken from stranded and biopsied animals between 1994 and 2008 in southern Galicia (N = 29), the Sado estuary (N = 5) and five other geographical locations (N = 57) including sites around the Iberian Peninsula, the Canary Islands and the Azores. Individuals were genotyped at 10 microsatellite loci and sequenced at the highly variable mitochondrial control region. From individual-based analyses of microsatellite data, dolphins from southern Galicia and the Sado estuary were assigned to an individual genetic population, though nine dolphins were identified as possible migrants between putative populations as their genetic makeup did not correspond with their geographical stranding location. Pairwise estimates of genetic differentiation (F ST) based on mitochondrial and nuclear DNA also revealed genetic differences between populations. The existence of fine-scale population substructure should be considered in the future designation of Special Areas of Conservation (SACs) for the species, as required by the European Habitats Directive.

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Acknowledgements

The authors gratefully acknowledge the assistance of volunteers from the Coordinadora para o Estudio dos Mamíferos Mariños (CEMMA), Sociedade Portuguesa de Vida Selvagem (SPVS), Canarias Conservación, Instituto da Conservaςão da Natureza and Sociedad para el Estudio y la Conservación de la Fauna Marina (AMBAR). We wish to thank M. Sequeira who provided tissue samples. Thanks to F. Marshall, G. Murray-Dickson, C.D. MacLeod and C. Gubili at the University of Aberdeen and to A. Centeno-Cuadros at the Estación Biolόgica de Doñana (CSIC) for useful comments during data analysis and discussion. R.F. was supported during the research period through Marie Curie Early-Stage Research Grant (ECOSUMMER project. 020501-2). G.J.P. was supported by the ANIMATE project (MEXC-CT-2006-042337). M.A.S. was supported by an FCT (Portuguese Science and Technology Foundation) postdoctoral grant (SFRH/BPD/29841/2006). IMAR-DOP/UAç is the R&D Unit #531 and part of the Associated Laboratory #9 (ISR) funded through the pluri-annual and programmatic funding schemes of FCT-MCTES and DRCT-Azores. Sample collection in The Azores was funded by the FCT, under the CETMARH project (POCTI/BSE/38991/01).

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Correspondence to Ruth Fernández.

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Guest editors: Graham J. Pierce, Vasilis D. Valavanis, Begoña M. Santos & Julio M. Portela / Marine Ecosystems and Sustainability

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Fernández, R., Santos, M.B., Pierce, G.J. et al. Fine-scale genetic structure of bottlenose dolphins, Tursiops truncatus, in Atlantic coastal waters of the Iberian Peninsula. Hydrobiologia 670, 111 (2011). https://doi.org/10.1007/s10750-011-0669-5

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Keywords

  • Genetic differentiation
  • Resident populations
  • Cetaceans
  • Migrants
  • Conservation