Alien species in the Mediterranean Sea by 2012. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part 2. Introduction trends and pathways

Abstract

More than 60 marine non-indigenous species (NIS) have been removed from previous lists and 84 species have been added, bringing the total to 986 alien species in the Mediterranean [775 in the eastern Mediterranean (EMED), 249 in the central Mediterranean (CMED), 190 in the Adriatic Sea (ADRIA) and 308 in the western Mediterranean (WMED)]. There were 48 new entries since 2011 which can be interpreted as approximately one new entry every two weeks. The number of alien species continues to increase, by 2-3 species per year for macrophytes, molluscs and polychaetes, 3-4 species per year for crustaceans, and 6 species per year for fish. The dominant group among alien species is molluscs (with 215 species), followed by crustaceans (159) and polychaetes (132). Macrophytes are the leading group of NIS in the ADRIA and the WMED, reaching 26-30% of all aliens, whereas in the EMED they barely constitute 10% of the introductions. In the EMED, molluscs are the most species-rich group, followed by crustaceans, fish and polychaetes. More than half (54%) of the marine alien species in the Mediterranean were probably introduced by corridors (mainly Suez). Shipping is blamed directly for the introduction of only 12 species, whereas it is assumed to be the most likely pathway of introduction (via ballasts or fouling) of another 300 species. For approximately 100 species shipping is a probable pathway along with the Suez Canal and/or aquaculture. Approximately 20 species have been introduced with certainty via aquaculture, while >50 species (mostly macroalgae), occurring in the vicinity of oyster farms, are assumed to be introduced accidentally as contaminants of imported species. A total of 18 species are assumed to have been introduced by the aquarium trade. Lessepsian species decline westwards, while the reverse pattern is evident for ship-mediated species and for those introduced with aquaculture. There is an increasing trend in new introductions via the Suez Canal and via shipping.

Ornamental fish in pet stores in Greece: a threat to biodiversity?

“…Despite the low number of ornamental fish species released in Greece, the possibility of other ornamental fish being introduced and established into the wild, either intentionally or unintentionally, still remains. Moreover, given that a number of introduced species of Indo-Pacific origin, recently reported in the eastern Mediterranean, belong to species kept in aquarium (Zenetos et al, 2012), a number of released sub-tropical/thermophilic fish species could become established and spread to the warmer southern parts of the country at least.…”

The Influence of the Spatial Scale on the Fishery Landings-SST Relationship

“…Studies in the Mediterranean Sea confirmed this pattern, both in terms of observations (Galil, 2008;Zenetos et al, 2012) and future projections (Ben Rais Lasram et al, 2010;Albouy et al, 2012).…”

On the occurrence of Uronema marinum Womersley (Chaetophorales, Chlorophyta) in the north-western lagoons of the Adriatic Sea, Mediterranean Sea (Italy)

“…At present, the number of macroalgal NIS reported in Venice Lagoon is 35, ca. 67% of the total number of alien macrophytes (52 taxa, Zenetos et al, 2012) recorded in the entire Adriatic Sea.…”

“…The latest lists of alien species in the Mediterranean Sea (Zenetos et al, 2010(Zenetos et al, , 2012 place this region amongst the most affected by biological invasions. In December 2010, the inventory of marine non indigenous species (NIS) included 955 taxa (except phytoplankton).…”