In the present paper, we report the collection of a specimen of the West central Atlantic Stegastes variabilis in the shores of Israel, eastern shore of the Mediterranean. This record was preceded by a record of this species from Malta, in the central Mediterranean. The present record suggests that S. variabilis has established a small population in the Mediterranean.

The magnitude of the invasive plant species problem necessitates prioritization of species for control, regulatory, and public-education programs. Many such priority lists exist but few have been developed according to specified procedures and criteria. We reviewed approaches to assessing the status of nonnative plant species currently occurring in natural areas (status assessments). We identify four generalized types of status assessments, which reflect a gradation from those that simply adopt existing lists from elsewhere (type 1), to those with relatively easy and rapid development and implementation (type 2), to those that are more time-consuming and costly but may be more robust in the face of challenges (types 3 and 4). These latter assessments explicitly have greater transparency, objectivity, and consistency than the other types. We use a matrix of assessment characteristics to distinguish the types of 17 example status assessments. We also review the factors related to assessment intent, scope, structure, content, and implementation that must be considered during the development of new status assessments so that the resulting tool and its products are appropriate for the user's purposes. These analyses should facilitate evaluation of different assessment methods and provide a basis for development of improved assessments. Identification of the relatively low percentage of nonnative plant species that are inflicting ecological and economic harm using well-understood and accepted assessment methods should facilitate a more comprehensive, collective approach to implementation of effective management efforts.

It is necessary to monitor shell-associated polydorid worms owing to the risk that they pose to commercially important molluscs. This requires accurate identification, but is often hampered by morphological similarities among species, insufficient type specimens, and abridged species descriptions. Thus morphological characteristics and molecular sequences of the most harmful polydorid species, Polydora uncinata from Japan and Australia and Polydora hoplura from South Africa were compared to determine whether they represent two morphologically similar, but genetically distinct species, or a single species. A wide range of morphological variation (with respect to size, length of caruncle and pigmentation patterns) was observed in each species and population, and their variations largely overlapped and revealed them to be at the intraspecific level of a single species. This was confirmed by gene sequences of nuclear 18S and 28S rRNA that were completely identical for P. uncinata and P. hoplura. The mitochondrial 16S rRNA and cyt b gene analyses also showed no genetic differences between these two species. The tree topology of the mitochondrial cyt b gene did not reflect geographic differences but instead suggests artificial transportation of the species. We recommend the synonymization of P. uncinata with P. hoplura.

We report the first record in the Mediterranean Sea of the minute Indo-Pacific venerid bivalve Costellipitar chordatum. The species has recently established a small population off the central coast of Israel. Numerous live specimens of Gouldiopa consternans, at several locations off the Israeli coast, confirm the presence of a fast growing population. This is the first record of the species from Israel, following a recent report from Turkey.

This paper reports for the first time the presence of Holothuria (Roweothuria) arguinensis in the Algerian coastal waters. Individuals of this species were taken from the Tamentefoust area (Bay of Algiers, Algeria, 3°13′E 36°48′N) at 4.5 m depth and examined, using traditional morphological and endoskeletal characters. The general body form and the ossicles are in accordance with the descriptions of the species obtained in the literature.

Cylichna villersii, a minute ‘bubble snail’ is newly recorded in the Mediterranean Sea from specimens recently collected along the Israeli coastline. The species, described and illustrated, matches the syntype collected in the Red Sea by Savigny. It is the eighth Erythraean alien cephalaspideid species recorded in the Levantine Basin. The recent collection of many living specimens in several continuously sampled locations attests to the speed of its establishment in the south-eastern Levant.

Saron marmoratus, a colourful Indo-Pacific ‘marble shrimp’, is newly recorded in the Mediterranean Sea from specimens recently photographed along the Israeli coastline. The colour pattern of the species is described and illustrated. It is the second Indo-Pacific hippolytid species recorded in the Mediterranean.

The ammotheid pycnogonid Ammothea hilgendorfi was first recorded outside its native range of the Pacific Ocean in 1978 in southern England and in the Lagoon of Venice in 1979 to 1981. Both occurrences are attributed to anthropogenic dispersion by shipping. Subsequently, it has spread further in the UK to Dorset and, most recently, to Essex. The world distribution of this species and the history of its occurrence outside the Pacific are reviewed, and hypotheses for its recent spread in the UK, via recreational boating, are presented.

Antarctic terrestrial ecosystems are not immune to the threat of biological invasions, and the urgent need for implementation of effective mitigation measures to minimize the risk has been highlighted. Recently, the transportation and logistic support system of the Japanese Antarctic Research Expedition has undergone substantial changes after the relocation of the cargo handling facility and the commissioning of a new icebreaker in 2009. The potential risk of introducing non-native species into Antarctica through the newly adopted cargo transportation system in comparison with the previously existing system was determined by quantifying both changes in the form of cargo transported and the frequency of propagule attachment on different types of cargo item. We obtained 1022 propagules of at least 26 species, including species known to have resistance to the stresses of cold environments. Larger numbers of propagules, and a greater proportion of affected cargo items, were encountered in the newly adopted transportation system than in its predecessor. The increased risks in the new system were identified as being associated with the major cargo packing type and the cargo storage location. Based upon those findings, we propose appropriate preventative measures in order to minimize the risk of transfer of non-native species into Antarctica.

Indo-Pacific originated foraminifera species Coscinospira acicularis individuals were found among a rich peneroplid assemblage around a submarine spring in Ilıca Bay on the west coast of Karaburun Peninsula (İzmir, Turkey). This constitutes the first observation of this species in the Mediterranean. The submarine spring is located at a depth of 2.5 m and has a temperature of 28.4°C. It is possible that the special ecological conditions created by the warm waters of the spring might have enhanced the establishment of this thermophilic species. Although the Suez Canal is considered to be the major vector for the introduction of Indo-Pacific species into the Mediterranean, its abundance in Ilıca Bay and lack of observation on the eastern Mediterranean coasts suggests that shipping is the most probable mode of introduction for this species.

Percnon gibbesi is an opportunistic feeder, feeding primarily on algae, of the shallow infra-littoral rocky shores. It was first observed in 1999 in the Mediterranean Sea and has rapidly spread since then. The range expansion of the species in the Aegean and Ionian Seas was recorded and evidence of its further establishment in Greek waters was provided. Established populations were observed in areas where it had not been previously reported: the Saronikos Gulf (central Aegean Sea), Chios Island (central Aegean Sea), Milos Island (central Aegean Sea), Zakynthos Island (central Ionian Sea) and Syvota (north-eastern coast of the Ionian Sea). The species was also observed in new sites in the Messiniakos Gulf, Crete and Rhodes Island, where it had been previously reported. The species keeps spreading in the Mediterranean Sea with a high rate of expansion.