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Mediterranean invasive species factsheet

Reproduction Economic impacts
In the Mediterranean Sea only vegetative Unknown.
reproduction is known and no fertile specimens have
been found. Management options
Once it has become invasive, eradication and even
Similar species containment are not possible. The species might be
controlled most efficiently and effectively, and at the
Although it can easily be confused with other
lowest cost, early in the invasive process.
filamentous red algae (i.e. Womersleyella setacea)
when directly observed in the field, the presence of
terminal gland cells at the end of most branches is a Further reading
useful character for identifying Acrothamnion Ferrer, E., et al. 1994. The spread of Acrothamnion preissii
preissii. (Sonder) Wollaston (Rhodophyta , Ceramiaceae) in the
Mediterranean Sea: New record from the Balearic Islands.
Fl. Medit. 4, 163-166.
Klein, J.C. & Verlaque, M., 2011. Macroalgae newly
recorded, rare or introduced to the French Mediterranean
coast. Cryptogamie Algologie 31(2), 111-130.
Piazzi,l. & F. Cinelli., 2000. Effects of expansion of
introduced Rhodophyceae Acrothamnion preisii and
Womersleyella setacea on the algal communites of
Posidonia oceanica rhizomes in the western
Mediterranean. Cryptogam. Algol., 21(3): 291-300.

Womersleyella setacea. Photo: E. Ballesteros

Brief history of its introduction and
pathways
An Indo-Pacific species native to Western Australia,
New Zealand, South Africa and Japan that has
probably been introduced into Europe by maritime
transport (on ship hulls). At present, it is mainly
distributed in the north-western Mediterranean,
forming invasive populations in France, Italy,
Monaco and Spain.

Ecological impacts
Ecological impacts of the red alga Acrothamnion
Drawings: Juan Varela
preissii are still largely unknown but, when invasive,
it becomes dominant outcompeting or replacing
most native algal species.

34 Monitoring Marine Invasive Species in Mediterranean MPAs: A strategy and practical guide for managers