Occurrence of Barred Knifejaw, &lt;I&gt;Oplegnathus Fasciatus&lt;/I&gt; (Actinopterygii: Perciformes: Oplegnathidae), in Malta (Central Mediterranean) with a Discussion on Possible Modes of Entry

485

444

The state-of-art on alien species in the Mediterranean Sea is presented, making distinctions among the four subregions defined in the EU Marine Strategy Framework Directive: (i) the Western Mediterranean Sea (WMED); (ii) the Central Mediterranean Sea (CMED); (iii) the Adriatic Sea (ADRIA); and (iv) the Eastern Mediterranean Sea (EMED). The updated checklist (December 2010) of marine alien species within each subregion, along with their acclimatization status and origin, is provided. A total of 955 alien species is known in the Mediterranean, the vast majority of them having being introduced in the EMED (718), less in the WMED (328) and CMED (267) and least in the Adriatic (171). Of these, 535 species (56%) are established in at least one area.Despite the collective effort of experts who attempted in this work, the number of introduced species remains probably underestimated. Excluding microalgae, for which knowledge is still insufficient, aliens have increased the total species richness of the Mediterranean Sea by 5.9%. This figure should not be directly read as an indication of higher biodiversity, as spreading of so many aliens within the basin is possibly causing biotic homogenization. Thermophilic species, i.e. Indo-Pacific, Indian Ocean, Red Sea, Tropical Atlantic, Tropical Pacific, and circum(sub)tropical, account for 88.4% of the introduced species in the EMED, 72.8% in the CMED, 59.3% in the WMED and 56.1% in the Adriatic. Cold water species, i.e. circumboreal, N Atlantic, and N Pacific, make up a small percentage of the introduced species, ranging between 4.2% and 21.6% and being more numerous in the Adriatic and less so in the EMED.Species that are classified as invasive or potentially invasive are 134 in the whole of the Mediterranean: 108 are present in the EMED, 76 in the CMED, 53 in the Adriatic and 64 in the WMED. The WMED hosts most invasive macrophytes, whereas the EMED has the lion’s share in polychaetes, crustaceans, molluscs and fish.

“…Evidence of established populations in the CMED are mostly related to the occurrence of multiple records of the same species, such as for Cephalopholis taeniops (SCHEMBRI et al, 2010b).…”

Section: Alien Fish In the Central Mediterraneanmentioning

confidence: 99%

Alien species in the Mediterranean Sea by 2010. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part I. Spatial distribution

Zenetos

Gofas

Verlaque³

et al. 2010

485

444

“…This species was first recorded in the Mediterranean Sea by Schembri et al (2010), on the basis of two individuals photographed in Grand Harbour, Valletta (Malta). The authors also provided a number of possible occurrence scenarios, all related to shipping agents.…”

Section: Figmentioning

confidence: 99%

New Mediterranean Biodiversity Records (October 2015)

Crocetta

Agius

Balistreri³

et al. 2015

101

“…The same authors rule out transport in ballast water. However, transport in a sea chest or similar water-filled space of a large vessel, such as postulated in the case of Oplegnathus fasciatus Temminck & Schlegel, 1844(Schembri et al 2010, is a possibility. It is also possible that the fish travelled in association with the fouling on the hull of a vessel, although in this regard, a slow moving barge or drilling platform is a more probable vector than a ship (see discussion in Galil, 2008).…”

Section: Discussionmentioning

confidence: 99%

Chlorurus rhakoura Randall & Anderson, 1997 (Perciformes, Scaridae), an Indo-Pacific fish new for the Mediterranean Sea

Insacco

Zava²

2017

The scarid fish Chlorurus rhakoura Randall & Anderson, 1997, of eastern Indo-Pacific origin, is recorded for the first time from the Mediterranean Sea. A small school of six individuals of this species were caught off Portopalo, Sicily, Italy in February 2017. Morphometric measurements and meristic traits are provided based on four specimens, and the possible vector of introduction of the species into the Mediterranean is briefly discussed.