Establishment of a coastal fish in the Azores : recent colonisation or sudden
expansion of an ancient relict population?

Stefanni, S; Castilho, S; Sala-Bozano, R; Robalo, JI; Francisco, SM; Santos, RS; Marques, N; Brito, A; Almada, VC; Mariani, S

Abstract

The processes and time scales 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 more than 1000 km off the European continental shelf,
offers ideal opportunities to investigate phylogeographic colonization 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 prior to the 1990s.
We employed a multiple genetic marker approach to test whether the successful establishment of the
Azorean population derives from a recent colonization 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 approximately 40 (95% C.I.: 5.5─83.6) to 52
(95% C.I.; 6.32─89.0) generations, corresponding to roughly 80-150 years, which suggests near
contemporary colonisation, followed by a more recent demographic expansion which 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.

Citation

expansion of an ancient relict population?. Heredity, 115, 527-537. https://doi.org/10.1038/hdy.2015.55

• Journal Article Type: Article
• Acceptance Date: May 6, 2015
• Publication Date: Jul 15, 2015
• Deposit Date: May 8, 2015
• Publicly Available Date: Apr 5, 2016
• Journal: Heredity
• Print ISSN: 0018-067X
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 115
• Pages: 527-537
• DOI: https://doi.org/10.1038/hdy.2015.55
• Publisher URL: http://dx.doi.org/10.1038/hdy.2015.55
• Related Public URLs: http://www.nature.com/hdy/index.html
• Additional Information: Funders : Fundação para a Ciência e Tecnologia (FCT); Projects : MarinERA project EU;FP7 People-2012-COFUND; Co-funding of Regional, National and International Programmes;Fundação para a Ciência e Tecnologia (FCT) grants; Grant Number: FP6 ERA-NET; Grant Number: GA n.600407; Grant Number: PEst-OE/MAR/UI0331/2011 & grant SFRH/BPD/84923/2012.