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

Habitat‐driven population structure of bottlenose dolphins, Tursiops truncatus, in the North‐East Atlantic

“…; Fernandez et al . ). Further diet studies are needed to document the niche specialization of the two groups and investigate the hypotheses described above.…”

“…Fine‐scale genetic structure was reported locally in Ireland and the Iberian Peninsula where a potential differentiation between pelagic and coastal dolphins was suggested (Fernandez et al . ; Mirimin et al . ).…”

Genetic isolation between coastal and fishery‐impacted, offshore bottlenose dolphin (Tursiops spp.) populations

“…), as it should be in coastal common bottlenose dolphins globally (Fernández et al . ; Mirimin et al . ; Moura et al .…”

Fine‐scale population structure and connectivity of bottlenose dolphins, Tursiops truncatus, in European waters and implications for conservation

“…between the Shannon estuary and the rest of the west coast of Ireland, Mirimin et al, 2011;Nykänen et al, 2018). Furthermore, the previous studies on bottlenose dolphin population structure (Fernandez et al, 2011;Louis, Viricel, et al, 2014;Mirimin et al, 2011;Natoli et al, 2003;Nykänen et al, 2018) have all employed different sets of microsatellite markers, preventing the comparison between studies, and thus giving a fragmented vision of population structure. However, these authors did not have large enough sample sizes from each local coastal population to fully investigate fine-scale structuring, and no samples were available from the population occupying the Shannon Estuary in Ireland.…”