Marine alien Mollusca in Italy: a critical review and state of the knowledge

Abstract

The state of the knowledge about the marine alien molluscan species from Italy is provided based on a critical review of records compiled from an extensive literature survey and from unpublished data obtained from 2005 to 2010. Based on the IUCN definition of ‘alien’, 35 molluscan taxa (18 Gastropoda, 16 Bivalvia and 1 Cephalopoda) are reported here, for each of which the following data (collected up to December 2010) are provided: published and unpublished records from the coastal and offshore territorial seawaters of Italy, including lagoons, within the 14 biogeographical sea divisions covering the Italian shores, date of first record, most plausible vector(s) of introduction and establishment status. The southern Ionian Sea, the northern Adriatic Sea and the eastern-central Tyrrhenian Sea resulted to be the areas most affected by alien molluscan introductions. The rate of records of new alien species (evaluated on the basis of live findings) is quite uniform over five decades, with six to eight species recorded per decade. The analysis of the vectors showed shipping/maritime transport to be the most common vector of introduction (40%), followed by trade (24%). Nineteen alien molluscan species (54%) were considered as established in Italy.

New Mediterranean Biodiversity Records (December 2012)

“…The occurrence of D. sayi in Lago Fusaro underlines the importance of the lagoon systems as hot-spots for the introduction and spreading of alien species (Cosentino et al, 2010;Crocetta, 2012). In this coastal lagoon, the presence of a commercial mussel farm as well as an established population of the alien clam Ruditapes philippinarum clearly points to aquaculture as the likely vector of introduction, as in previous Adriatic records.…”

Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda) from Lebanon

“…This is mostly the case of shelled, larger-sized and/or easy-toidentify species, which lack morphologically similar native Mediterranean counterparts or have been recorded earlier based on empty shells found in bioclastic sediments. In addition, the alien spreading of B. leachii, A. dactylomela and S. geographica in the Mediterranean is outstanding: the three species having been able to colonize the central part of the basin (Crocetta, 2012), with scattered records of the former up to the western part (Ibáñez-Yuste et al, 2012). Conversely, other species have only recently formed established populations in the eastern Mediterranean, such as G.…”

Biogeographical homogeneity in the eastern Mediterranean Sea. II. Temporal variation in Lebanese bivalve biota

“…Using the bibliographic data available, the past (before 1950) and modern (after 1950) bivalve faunal lists were qualitatively compared. Special em phasis was given to alien species, for each of which the following data are provided: published and un published records from the coastal and offshore territorial seawaters of Lebanon, date of first record, most plausible vector(s) of introduction and establishment status, mostly following the terminology used in Crocetta (2012).…”