title: Habitat-driven population structure of bottlenose dolphins, Tursiops truncatus, in the North-East Atlantic.
abstract: Despite no obvious barrier to gene flow, historical environmental processes and ecological specializations can lead to genetic differentiation in highly mobile animals. Ecotypes emerged in several large mammal species as a result of niche specializations and/or social organization. In the North-West Atlantic, two distinct bottlenose dolphin (Tursiops truncatus) ecotypes (i.e. 'coastal' and 'pelagic') have been identified. Here, we investigated the genetic population structure of North-East Atlantic (NEA) bottlenose dolphins on a large scale through the analysis of 381 biopsy-sampled or stranded animals using 25 microsatellites and a 682-bp portion of the mitochondrial control region. We shed light on the likely origin of stranded animals using a carcass drift prediction model. We showed, for the first time, that coastal and pelagic bottlenose dolphins were highly differentiated in the NEA. Finer-scale population structure was found within the two groups. We suggest that distinct founding events followed by parallel adaptation may have occurred independently from a large Atlantic pelagic population in the two sides of the basin. Divergence could be maintained by philopatry possibly as a result of foraging specializations and social organization. As coastal environments are under increasing anthropogenic pressures, small and isolated populations might be at risk and require appropriate conservation policies to preserve their habitats. While genetics can be a powerful first step to delineate ecotypes in protected and difficult to access taxa, ecotype distinction should be further documented through diet studies and the examination of cranial skull features associated with feeding.
authors.affiliation: Centre d'Etudes Biologiques de Chizé, UPR 1934, 79360, Villiers-en-Bois, France; Littoral, Environnement et Sociétés (LIENSs), UMR 7266, CNRS/Université de La Rochelle, 2 rue Olympe de Gouges, 17000, La Rochelle, France; GECC (Groupe d'Etude des Cétacés du Cotentin), Place des Justes, 50130, Cherbourg-Octeville, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Louis
authors.forename: Amélia
authors.initials: A
authors.lastname: Viricel
authors.forename: Tamara
authors.initials: T
authors.lastname: Lucas
authors.forename: Hélène
authors.initials: H
authors.lastname: Peltier
authors.forename: Eric
authors.initials: E
authors.lastname: Alfonsi
authors.forename: Simon
authors.initials: S
authors.lastname: Berrow
authors.forename: Andrew
authors.initials: A
authors.lastname: Brownlow
authors.forename: Pablo
authors.initials: P
authors.lastname: Covelo
authors.forename: Willy
authors.initials: W
authors.lastname: Dabin
authors.forename: Rob
authors.initials: R
authors.lastname: Deaville
authors.forename: Renaud
authors.initials: R
authors.lastname: de Stephanis
authors.forename: François
authors.initials: F
authors.lastname: Gally
authors.forename: Pauline
authors.initials: P
authors.lastname: Gauffier
authors.forename: Rod
authors.initials: R
authors.lastname: Penrose
authors.forename: Monica A
authors.initials: MA
authors.lastname: Silva
authors.forename: Christophe
authors.initials: C
authors.lastname: Guinet
authors.forename: Benoit
authors.initials: B
authors.lastname: Simon-Bouhet
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D050681:Bottle-Nosed Dolphin / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D017753:Ecosystem; D014644:Genetic Variation; D005828:Genetics, Population; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D011156:Population Density; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial
keywords: cetaceans; conservation; ecotypes; feeding specializations; philopatry; population genetics