Biological Invasions

, Volume 12, Issue 8, pp 2707–2721

Pathways of spread of the introduced ascidian Styela clava (Tunicata) in Northern Europe, as revealed by microsatellite markers

  • L. Dupont
  • F. Viard
  • M. H. Davis
  • T. Nishikawa
  • J. D. D. Bishop
Original Paper


Styela clava, a solitary ascidian native to the NW Pacific, has become a conspicuous member of fouling communities in NW European waters. As its natural dispersal appears to be limited, the wide distribution of S. clava along coasts within its introduced range may be attributed to secondary spread assisted by human activities. Here, we used six microsatellite loci to examine the genetic diversity and extent of gene flow among S. clava populations in its European introduced range. Samples were collected from 21 populations within Europe (N = 808), 4 populations within the USA and two populations within the native range (Japan). Large variation in genetic diversity was observed among the European populations but were not explained either by the geographic distance from the first introduction area (i.e. Plymouth, UK) nor by the time elapsed since the introduction. No founder effect was observed in the introduced populations, except possibly in Puget Sound (USA). At least two different introductions occurred in Europe, identified as distinct genetic clusters: northern Danish populations (resembling one Japanese population), and the rest of Europe; a sample from Shoreham (England) possibly represents a third introduction. In North America, the population from the Atlantic was genetically similar to the majority of European populations, suggesting a European origin for populations on this seaboard, while populations from the Pacific coast were genetically similar to the same Japanese population as the Danish populations.


Biological invasion Gene flow Larval dispersal Microsatellite Genetic diversity Founder effect 


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Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • L. Dupont
    • 1
    • 7
  • F. Viard
    • 2
    • 3
  • M. H. Davis
    • 4
  • T. Nishikawa
    • 5
  • J. D. D. Bishop
    • 1
    • 6
  1. 1.Marine Biological AssociationCitadel Hill, PlymouthUK
  2. 2.UPMC Univ Paris 06, UMR 7144, Equipe Div&CoStation BiologiqueRoscoffFrance
  3. 3.CNRS, UMR 7144, Adaptation & Diversité en Milieu MarinStation BiologiqueRoscoffFrance
  4. 4.Nuclear DepartmentHMS SultanGosport, HampshireUK
  5. 5.Nagoya University MuseumChikusa-kuJapan
  6. 6.School of Biological SciencesUniversity of PlymouthPlymouthUK
  7. 7.UMR 7618 BioEMCo, Equipe IBIOSUniversité Paris-EstCréteil CedexFrance

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