by Xavier Turon
The article “
When invasion biology meets taxonomy: Clavelina oblonga (Ascidiacea) is an old invader in the Mediterranean Sea” by Víctor Ordóñez, Marta Pascual, Margarita Fernández and Xavier Turon is now published online in Biological Invasions.
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| An oyster culture rope totally covered by colonies of Clavelina oblonga. |
In this paper we report the taxonomic status of a marine pest that has recently proliferated in bivalve cultures of the Ebro Delta, smothering mussel spat and causing concern among fishermen. The species was initially identified as
Clavelina phlegraea, described in 1929 in Italy and endemic of the Mediterranean. Further morphological and genetic studies, however, have concluded that
C. phlegraea is a synonym of the Atlantic species
C. oblonga, which has been introduced into the Mediterranean at least 80 years ago, but was known under a different name there. This study illustrates the problems of traditional taxonomy to cope with the global-scale distribution of introduced species.
We have also monitored growth and reproductive cycles of
C. oblonga in the Ebro Delta, which were markedly seasonal, with peak abundance and reproduction in summertime, followed by regression in winter. Avoidance of mussel and oyster seeding during late summer and early autumn can readily reduce the damage caused by this species.
