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Mediterranean invasive species factsheet

Similar species geographical expansion through the eastern
Two species of the rabbitfish family Siganidae are Mediterranean. In 2008, two specimens were caught
now present in the Mediterranean, both having along the French Mediterranean coast at a depth of
arrived via the Suez Canal. Siganus rivulatus, the about 5-10 m in a site mostly characterized by rocky
marbled spinefoot, can be distinguished by its forked bottoms mixed with Posidonia oceanica beds. In
caudal fin. Their diets overlap considerably. Both 2010, it was also recorded in two different localities in
these rabbitfish also share a common habitat and the Adriatic Sea (Gulf of Trieste and southern Adriatic
diet with the native herbivorous fish Sarpa salpa, the Sea, island of Mljet). Several specimens were also
salema. The salema has characteristic horizontal observed and photographed in France close to the
yellow lines on its body, yellow circles round its eyes, Italian border between November 2011 and July 2012.
and a black dot at the base of the pectoral fins.
Ecological impacts
The two species belonging to the Siganidae family,
Caudal fin forked Siganus luridus and S. rivulatus, have become very
common in most parts of the eastern Mediterranean
and strongly interact with native herbivorous fish
species through competition for food resources and
habitat. The spread of these two herbivorous species
can result in a drastic decrease in seaweed
Siganus rivulatus
formations. Some of these, such as Cystoseira spp.
Body more elongated with brown to
yellow abdomen and fine yellow stripes forests, are ecologically very important as nurseries
for a number of littoral fish species. These Cystoseira
forests are currently considered to be a threatened
Yellow eye
Dark spot
Caudal fin forked habitat in several regions of the Western
and dark grey
Mediterranean. It will therefore be crucial to monitor
the establishment of rabbitfish assemblages in the
Western Mediterranean in the future.

Sarpa salpa
Grey bluish body colouration with 10- Economic impacts
12 well marked golden stripes
Due to its great abundance in the Eastern
Mediterranean, the dusky spinefoot is regularly caught
by small-scale professional and non-professional
fishers. However, it is of low commercial value.

Management options
Suggested control measures are a) early
eradication of new populations by MPA technicians
through spear fishing, and b) maintenance of healthy
and abundant predator assemblages to encourage
natural control through predation.
Sarpa salpa. Photo: M. Otero
Further reading
Brief history and route of
introduction Fischer, W., M. L. Bauchot and M. Schneider (eds) 1987.
Fiches FAO d’identification des espèces pour les besoins
The dusky spinefoot is a species usually found in the de la pêche (Révision 1). Méditerranée et mer Noire. Zone
western Indian Ocean and Red Sea. It was first de pêche 37. Volume II. Vertébrés. Rome , FAO , Vol.2: Drawings: Juan Varela
761–1530
recorded in the Mediterranean in 1956 along the
Israeli coast and progressively continued its http://www.ciesm.org/atlas/Siganusluridus.php

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