Page 1 - Gianguzza_alii_2006

Biol. Mar. Medit. (2006), 13 (1): 588-590

P. GianGuzza, B. zava*, C. Bonaviri, G. Monteverde, a. PalMeri, S. riGGio
Dipartimento di Biologia Animale, Università degli Studi di Palermo,
Via Archirafi, 18 – 90123 Palermo, Italia.
pgiangu@unipa.it
*Wilderness – Studi ambientali, Palermo, Italia.

NOTES ON THE FISH ASSEMBLAGES
IN THE AREAS INVADED BY CaUlerpa SPP. (ULVOPHY�EAE,(ULVOPHY�EAE,
�HLOROPHYTA) ALONG THE SI�ILIAN �OASTS

Note sUI popolaMeNtI IttICI
preseNtI NeI CaUlerpetI delle aCqUe sICIlIaNe

Abstract
an evaluation of the coastal fish assemblages present in sicilian waters colonized by the alien �aulerpa
taxifolia, �. racemosa and the authoctonous �. prolifera was carried out in late summer 2004. a total of
28 species, representing 8 families, for a total of 1298 individuals, were recorded. results demonstrated that
the fish assemblage of the location colonized by �. taxfiolia significantly differed from those covered by �.
racemosa and �. prolifera.

Key-words: introduced species, Mediterranean sea, soft bottom.

Introduction
Studies on Mediterranean algal invasions showed that Caulerpa taxifolia
(Vahl) �. Agardh and C. racemosa (Forsskål) J. Agardh are a threat to local
seagrass and seaweed stands (Meinesz et al., 2001; Piazzi et al., 2001). In coloni-
zed areas these species tend to constitute monospecific beds inducing a persistent
decrease in mean species richness, density and biomass of the inhabiting motile
invertebrates (Bellan-Santini et al., 1996) and fish assemblages (Harmelin-Vivien
et al., 1999). An evaluation of the coastal fish assemblages present in three Sici-
lian areas colonized separately by the alloctonous C. taxifolia, C. racemosa and
the authoctonous C prolifera (Forskål) Lamouroux was carried out in the summer
2004 at Favignana Island, Province of Trapani (Western Sicily), Balestrate and
�asteldaccia, Province of Palermo (NW Sicily) respectively. This study investi-
gated whether fish assemblages present on alien Caulerpa beds were characte-
rized by a lower species richness than that of the autochthonous C. prolifera.
The impacts of C. racemosa and C. taxifolia beds on fish assemblages have been
studied using unique, separate beds from a broad sampling area because of their
different distribution along the Sicilian coasts. There are several areas colonized
by C. racemosa, very few by C. prolifera and only two by C. taxifolia (Gianguzza,
unpublished data) in Sicilian waters and to date, there are no reports of intersper-
sed beds of alien and native species of Caulerpa.

Materials and methods
Data on the fish assemblages were recorded by underwater visual censuses along
25 m × 5 m transects (Harmelin-Vivien et al., 1985) in June, July and August 2004.