Drivers of Population Structure of the Bottlenose Dolphin (Tursiops truncatus) in the Eastern Mediterranean Sea
- 726 Downloads
The drivers of population differentiation in oceanic high dispersal organisms, have been crucial for research in evolutionary biology. Adaptation to different environments is commonly invoked as a driver of differentiation in the oceans, in alternative to geographic isolation. In this study, we investigate the population structure and phylogeography of the bottlenose dolphin (Tursiops truncatus) in the Mediterranean Sea, using microsatellite loci and the entire mtDNA control region. By further comparing the Mediterranean populations with the well described Atlantic populations, we addressed the following hypotheses: (1) bottlenose dolphins show population structure within the environmentally complex Eastern Mediterranean Sea; (2) population structure was gained locally or otherwise results from chance distribution of pre-existing genetic structure; (3) strong demographic variations within the Mediterranean basin have affected genetic variation sufficiently to bias detected patterns of population structure. Our results suggest that bottlenose dolphin exhibits population structures that correspond well to the main Mediterranean oceanographic basins. Furthermore, we found evidence for fine scale population division within the Adriatic and the Levantine seas. We further describe for the first time, a distinction between populations inhabiting pelagic and coastal regions within the Mediterranean. Phylogeographic analysis suggests that current genetic structure, results mostly from stochastic distribution of Atlantic genetic variation, during a recent post-glacial expansion. Comparison with Atlantic mtDNA haplotypes, further suggest the existence of a metapopulation across North Atlantic/Mediterranean, with pelagic regions acting as source for coastal environments.
KeywordsPopulation structure Phylogeography Tursiops truncatus Mediterranean Sea Gene flow
This research was funded by the Italian DG Fishery within the research framework of the Italian obligations to the Council Regulation (EC) n. 812/2004 (BYCATCH programme). The authors acknowledge the people that have provided samples: Israeli Marine Mammal Research and Assistance Center (IMMRAC, Dan Karem); Blue World Institute, Croatia, Marine Mammals Tissue Bank, University of Padoa, Italy (Bruno Cozzi, Maristella Giurisato); Università degli Studi di Siena, Italy (Letizia Marsili); Morigenos, Slovenia A.R.C.H.E. Porto Garibaldi, Italy (Carola Vallini); Fondazione Cetacea, Italy (Marco Affronte); Tethys Research Institute, Italy (Ada Natoli); Capitaneria di Porto di Brindisi, Italy (Paola Pino d’Astore). We would also like to thank the researchers and volunteers of IMMRAC, Israel.
- Almada, V. C., Oliveira, R. F., Goncalves, E. J., Almeida, A. J., Santos, R. S., & Wirtz, P. (2001). Patterns of diversity of the north-eastern Atlantic blenniid fish fauna (Pisces: Blenniidae). Global Ecology and Biogeography, 10, 411–422.Google Scholar
- Bearzi, G., & Fortuna, C. M. (2006). Common bottlenose dolphin Tursiops truncatus (Mediterranean subpopulation). In R. R. Reeves & G. Notarbartolo di Sciara (Eds.), The status and distribution of cetaceans in the Black Sea and Mediterranean Sea (pp. 64–73). Malaga: IUCN Centre for Mediterranean Cooperation.Google Scholar
- Caballero, S., Islas-Villanueva, V., Tezanos-Pinto, G., Duchene, S., Delgado-Estrella, A., Sanchez-Okrucky, R., et al. (2012). Phylogeography, genetic diversity and population structure of common bottlenose dolphins in the wider Caribbean inferred from analyses of mitochondrial DNA control region sequences and microsatellite loci: Conservation and management implications. Animal Conservation, 15, 95–112.CrossRefGoogle Scholar
- Calvo, M., Templado, J., Oliverio, M., & Machordom, A. (2009). Hidden Mediterranean biodiversity: Molecular evidence for a cryptic species complex within the reef building vermetid gastropod Dendropoma petraeum (Mollusca: Caenogastropoda). Biological Journal of Linnean Society, 96, 898–912.CrossRefGoogle Scholar
- Carreras, C., Pascual, M., Cardona, L., Aguilar, A., Margaritoulis, D., Rees, A., et al. (2006). The genetic structure of the loggerhead sea turtle (Caretta caretta) in the Mediterranean as revealed by nuclear and mitochondrial DNA and its conservation implications. Conservation Genetics, 8, 761–775.CrossRefGoogle Scholar
- Casado-Amezúa, P., Goffredo, S., Templado, J., & Machordom, A. (2012). Genetic assessment of population structure and connectivity in the threatened Mediterranean coral Astroides calycularis (Scleractinia, Dendrophylliidae) at different spatial scales. Molecular Ecology, 21, 3671–3685.CrossRefPubMedGoogle Scholar
- Domingues, V. S., Santos, R. S., Brito, A., Alexandrou, M., & Almada, V. C. (2007). Mitochondrial and nuclear markers reveal isolation by distance and effects of pleistocene glaciations in the northeastern Atlantic and Mediterranean populations of the white seabream (Diplodus sargus, l.). Journal of Experimental Marine Biology and Ecology, 346, 102–113.CrossRefGoogle Scholar
- Galarza, J. A., Carreras-Carbonell, J., Macpherson, E., Pascual, M., Roques, S., Turner, G. F., et al. (2009). The influence of oceanographic fronts and early-life-history traits on connectivity among littoral fish species. Proceeding of the National Academy of Sciences USA, 106, 1473–1478.CrossRefGoogle Scholar
- Gaspari, S., Holcer, D., Mackelworth, P., Fortuna, C., Frantzis, A., Genov, T., et al. (2013). Population genetic structure of common bottlenose dolphins (Tursiops truncatus) in the Adriatic Sea and contiguous regions: Implications for international conservation. Aquatic Conservation: Marine Freshwater Ecosystem. doi: 10.1002/aqc.2415.Google Scholar
- Genov, T., Kotnjek, P., Lesjak, J., Hace, A., & Fortuna, C. M. (2008). Bottlenose dolphins (Tursiops truncatus) in Slovenian and adjacent waters (northern Adriatic Sea). Annales Series Historia Naturalis, 18(2), 227–244.Google Scholar
- Goudet, J. (2001). FSTAT, a program to estimate and test gene diversities and fixation indices (version 2.9.3). http://www.unil.ch/izea/softwares/fstat.html
- Kiszka, J., Simon-Bouhet, B., Gastebois, C., Pusineri, C., & Ridoux, V. (2012). Habitat partitioning and fine scale population structure among insular bottlenose dolphins (Tursiops aduncus) in a tropical lagoon. Journal of Experimental Marine Biology and Ecology, 416–417, 176–184.CrossRefGoogle Scholar
- Moura, A. E., Janse van Rensburg, C., Pilot, M., Tehrani, A., Best, P. B., Thornton, M., et al. (2014). Killer whale nuclear genome and mtDNA reveal widespread population bottleneck during the last glacial maximum. Molecular Biology and Evolution, 31, 1121–1131.CrossRefPubMedCentralPubMedGoogle Scholar
- Park, S. D. E. (2008). Excel microsatellite toolkit. Computer program and documentation distributed by the author. http://animalgenomics.ucd.ie/sdepark/ms-toolkit/. Accessed June 2013.
- Parsons, K. M., Noble, L. R., Reid, R. J., & Thompson, P. M. (2002). Mitochondrial genetic diversity and population structuring of UK bottlenose dolphins (Tursiops truncatus): Is the NE Scotland population demographically and geographically isolated? Biology Conservation, 108, 175–182.CrossRefGoogle Scholar
- Pleslić, G., Rako, N., Mackelworth, P., Wiemann, A., Holcer, D., & Fortuna, C. (2013). The abundance of common bottlenose dolphins (Tursiops truncatus) in the former marine protected area of the Cres-Lošinj archipelago, Croatia. Aquatic Conservation: Marine Freshwater Ecosystem. doi: 10.1002/aqc.2416.Google Scholar