title: Establishment of a coastal fish in the Azores: recent colonisation or sudden expansion of an ancient relict population?
abstract: The processes and timescales associated with ocean-wide changes in the distribution of marine species have intrigued biologists since Darwin's earliest insights into biogeography. The Azores, a mid-Atlantic volcanic archipelago located >1000 km off the European continental shelf, offers ideal opportunities to investigate phylogeographic colonisation scenarios. The benthopelagic sparid fish known as the common two-banded seabream (Diplodus vulgaris) is now relatively common along the coastline of the Azores archipelago, but was virtually absent before the 1990 s. We employed a multiple genetic marker approach to test whether the successful establishment of the Azorean population derives from a recent colonisation from western continental/island populations or from the demographic explosion of an ancient relict population. Results from nuclear and mtDNA sequences show that all Atlantic and Mediterranean populations belong to the same phylogroup, though microsatellite data indicate significant genetic divergence between the Azorean sample and all other locations, as well as among Macaronesian, western Iberian and Mediterranean regions. The results from Approximate Bayesian Computation indicate that D. vulgaris has likely inhabited the Azores for ∼ 40 (95% confidence interval (CI): 5.5-83.6) to 52 (95% CI: 6.32-89.0) generations, corresponding to roughly 80-150 years, suggesting near-contemporary colonisation, followed by a more recent demographic expansion that could have been facilitated by changing climate conditions. Moreover, the lack of previous records of this species over the past century, together with the absence of lineage separation and the presence of relatively few private alleles, do not exclude the possibility of an even more recent colonisation event.
authors.affiliation: CNR-ISSIA, Via de Marini 6, Genova, Italy.|LARSyS Associated Laboratory and Centre of IMAR of the University of the Azores, Department of Oceanography and Fisheries, Horta, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Stefanni
authors.affiliation: Centre of Marine Sciences, CCMAR, Universidade do Algarve, Faro, Portugal.
authors.forename: R
authors.initials: R
authors.lastname: Castilho
authors.affiliation: School of Biology and Environmental Science, University College Dublin, Belfield, Ireland, UK.
authors.forename: M
authors.initials: M
authors.lastname: Sala-Bozano
authors.affiliation: MARE-Marine and Environmental Sciences Centre, ISPA-IU, Lisboa, Portugal.
authors.forename: J I
authors.initials: JI
authors.lastname: Robalo
authors.affiliation: MARE-Marine and Environmental Sciences Centre, ISPA-IU, Lisboa, Portugal.
authors.forename: S M
authors.initials: SM
authors.lastname: Francisco
authors.affiliation: LARSyS Associated Laboratory and Centre of IMAR of the University of the Azores, Department of Oceanography and Fisheries, Horta, Portugal.
authors.forename: R S
authors.initials: RS
authors.lastname: Santos
authors.affiliation: LARSyS Associated Laboratory and Centre of IMAR of the University of the Azores, Department of Oceanography and Fisheries, Horta, Portugal.
authors.forename: N
authors.initials: N
authors.lastname: Marques
authors.affiliation: BIOECOMAC, Departamento de Biología Animal (Ciencias Marinas), Universidad de La Laguna, Tenerife, Canary Islands.
authors.forename: A
authors.initials: A
authors.lastname: Brito
authors.affiliation: MARE-Marine and Environmental Sciences Centre, ISPA-IU, Lisboa, Portugal.
authors.forename: V C
authors.initials: VC
authors.lastname: Almada
authors.affiliation: Ecosystems and Environment Research Centre, School of Environment and Life Science, University of Salford, Salford, UK.
authors.forename: S
authors.initials: S
authors.lastname: Mariani
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D001394:Azores; D001499:Bayes Theorem; D004272:DNA, Mitochondrial / Q000235:genetics; D005819:Genetic Markers; D014644:Genetic Variation; D005828:Genetics, Population; D006239:Haplotypes; D018895:Microsatellite Repeats; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics*; D058974:Phylogeography; D017422:Sequence Analysis, DNA
chemical_list: D004272:DNA, Mitochondrial; D005819:Genetic Markers