Biological Invasions

, Volume 18, Issue 4, pp 1203–1215

When invasion biology meets taxonomy: Clavelina oblonga (Ascidiacea) is an old invader in the Mediterranean Sea

  • Víctor Ordóñez
  • Marta Pascual
  • Margarita Fernández-Tejedor
  • Xavier Turon
Original Paper

DOI: 10.1007/s10530-016-1062-0

Cite this article as:
Ordóñez, V., Pascual, M., Fernández-Tejedor, M. et al. Biol Invasions (2016) 18: 1203. doi:10.1007/s10530-016-1062-0


Taxonomic issues often confound the study of invasive species, which sometimes are unrecognized as introduced in newly colonized areas. Clavelina oblonga Herdman, 1880 is an abundant ascidian species along the southeastern coast of the United States and the Caribbean Sea. It was introduced into the eastern Atlantic and Brazil decades ago. In the Mediterranean Sea, a similar species had been described as C. phlegraea Salfi 1929 and reported from southern Italy and Corsica. In the last few years a species of Clavelina has proliferated in the embayments of the Ebro Delta (NW Mediterranean), a zone of active bivalve culture industry where it has smothered mussel spat, leading to economic loss. We here report the morphological and genetic identity of this species, synonymizing the Atlantic C. oblonga and the Mediterranean C. phlegraea (the latter therefore is a synonym of the former). Thus, C. oblonga has existed in the Mediterranean for over 80 years, but was known under a different name. We also found this species in natural habitats in the Iberian Atlantic coast close to the Strait of Gibraltar, raising concerns about an ongoing expansion. In order to obtain information relevant for management, we monitored growth, reproductive cycles and settlement patterns of this ascidian on bivalve cultures in the Ebro Delta. Its biological cycles were markedly seasonal, with peak abundance and reproduction during the warmest months, followed by regression during the cold season. The settlement period was short, mostly concentrated in a single month each year. Avoidance of mussel and oyster seeding during late summer and early autumn can readily reduce the damage caused by this species.


Ascidian Clavelina phlegraea Life cycle Recruitment Aquaculture pest Fouling 

Supplementary material

10530_2016_1062_MOESM1_ESM.docx (892 kb)
Supplementary material 1 (DOCX 892 kb)

Funding information

Funder NameGrant NumberFunding Note
Ministry of Economy and Competitiveness (Spain)
  • CTM2010-22218
Ministry of Economy and Competitiviness (Spain)
  • CTM2013-48163
Generalitat de Catalunya (ES)
  • SGR2014-336
European Commission (BE)
  • COCONET FP7 287844
Ministry of Education (Spain)
  • AP2008/04209

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Víctor Ordóñez
    • 1
  • Marta Pascual
    • 1
  • Margarita Fernández-Tejedor
    • 2
  • Xavier Turon
    • 3
  1. 1.Department of Genetics and IRBioUniversity of BarcelonaBarcelonaSpain
  2. 2.Institute of Agriculture and Food Research and Technology (IRTA)S. Carles de la RàpitaSpain
  3. 3.Center for Advanced Studies of Blanes (CEAB-CSIC)Blanes, GironaSpain

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