Population structure and historical demography of eastern North Atlantic harbour porpoises inferred through mtDNA sequences
Journal article, Peer reviewed
Permanent lenke
http://hdl.handle.net/11250/109120Utgivelsesdato
2006-12-07Metadata
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Originalversjon
http://dx.doi.org/10.3354/meps327297Sammendrag
The harbour porpoise Phocoena phocoena experiences high rates of incidental mortality
in commercial fisheries, and in some areas these rates are sufficiently high to justify concern over
population sustainability. Given this high mortality, conservation efforts may be facilitated by an
understanding of how present-day population structure has been shaped by historical demographic
changes. To investigate the demographic history of porpoises in the eastern North Atlantic, variation
in the mitochondrial DNA (mtDNA) control region of 115 porpoises was compared among 4 sampling
locations (North Sea, France, Portugal, and West Africa). Genetic variation was investigated by
analysis of molecular variance (AMOVA) and spatial analysis of molecular variance (SAMOVA). To
put the present study in context within the eastern Atlantic, previously published sequence data from
Norway (n = 87) and the Black Sea (n = 9) were included. All areas showed substantial geographic
structure as indicated by AMOVA and SAMOVA, and there was significant isolation by distance
among sampling areas. The haplotype network, mismatch distribution and Fu’s FS test of population
equilibrium suggest there has been a relatively recent range expansion into the northernmost area
(Norway), probably as a result of re-colonisation into regions previously iced over during Quaternary
glaciation events. In all, these results suggest that harbour porpoises within the eastern North
Atlantic show geographic structuring as a consequence of limited gene flow along the coast, and their
historical biogeography can be interpreted in light of demographic changes that have influenced the
evolutionary patterns observed in the mtDNA sequences.