Updated review of marine alien species and other ‘newcomers’ recorded from the Maltese Islands (Central Mediterranean)

Abstract

An updated review of marine alien species and other 'newcomers' recorded from the Maltese Islands is presented on account of new records and amendments to a previous review in 2007. Species were classified according to their establishment status ('Questionable', 'Casual', 'Established', 'Invasive') and origin ('Alien', 'Range expansion', 'Cryptogenic'). A total of 31 species were added to the inventory, while 6 species have been removed, bringing the total number of species to 73. Of these, 66 are considered to be aliens (or putative aliens but with uncertain origin) with the remaining 7 resulting from range expansion. Six records are considered to be questionable and hence unverified. For verified records, the dominant taxonomic groups are Mollusca (represented by 21 species) and Actinopterygii (15 species), followed by Crustacea (8 species) and Rhodophyta (7 species). Eight of these species (aliens: Caulerpa cylindracea, Lophocladia lallemandi, Womersleyella setacea, Brachidontes pharaonis, Percnon gibbesi, Fistularia commersonii, Siganus luridus; range extender: Sphoeroides pachygaster) are considered to be invasive. The introduction pathway for 30 species is unknown. Amongst the alien species, 'Shipping' is the most common introduction pathway, followed by 'Secondary dispersal' from elsewhere in the Mediterranean Sea. An increasing trend in the number of alien marine species reported from the Maltese Islands is evident, with a peak of 22 species recorded during the last decade (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010). A discussion on the rationale for including range-expanding species in national inventories of recent arrivals, and in the analysis of trends in records from the Maltese Islands, is included. In particular, the general warming trend of Mediterranean surface waters appears to be facilitating the westward spread of thermophilic alien species from the Eastern to the Central Mediterranean, and the eastward range expansion of tropical and subtropical Eastern Atlantic species.

New Mediterranean Biodiversity Records (October 2015)

“…The present record from the Maltese Islands makes this flatworm the umpteenth addition to the list of sixtysix alien species already confirmed for the waters around the islands (Evans et al, 2015), and the first non-indigenous platyhelminth recorded from the area. As live individuals were observed on four occasions at different coastal localities, always in small aggregations and never as single individuals, we suggest that the species is wellestablished in Maltese coastal waters.…”

Recent Trends and Impacts of Fisheries Exploitation on Mediterranean Stocks and Ecosystems

“…This was summarized from the CIESM Atlas of exotic species in Mediterranean (http://www.ciesm.org/online/atlas/) and complemented with supplementary bibliographic information from specific areas (Katsanevakis et al, 2009;Evans et al, 2015).…”

Morphological and genetic barcoding study confirming the first Stegastes variabilis (Castelnau, 1855) report in the Mediterranean Sea

“…However there have also been reports of species of this genus entering the Mediterranean Sea through the Suez Canal with a first recorded in Israel in 1998 (Golani et al, 2012), while other reports of this genus have been recorded more recently along the coast of Tarragona in Spain (Azzurro et al, 2013) and in Malta by the authors in 2013 (Vella, 2014 a & b), followed by Deidun & Castriota (2014). These local reports were in turn listed in a review by Evans et al (2015). Another Pomacentridae that has been recorded in the Mediterranean, Chrysiptera cyanea (Quoy & Gaimard, 1825), was collected from the Gulf of Trieste, North Adriatic Sea (Lipej et al, 2014).…”