A population of Rangia cuneata (G.B. Sowerby I, 1831), an estuarine bivalve, has been recorded in the harbour of Antwerp, Belgium. This species is new to the European brackish water fauna. After initially finding only a few small individuals in August 2005, R. cuneata was encountered frequently in the pipes of the cooling water system of an industrial plant from February 2006 onwards. Before this present record, R. cuneata was only known from the Gulf of Mexico and the Atlantic coast of North America.

A population of the Oriental River Prawn Macrobrachium nipponense is recorded from Anzali Lagoon, along the shores of the southern Caspian Sea in Iran, with the first recorded specimens encountered in 1998. Based on available evidence it is postulated that the species is already widespread in countries to the east and south of the Caspian Sea, but as yet unrecorded in several countries.

In August 2006, the ten largest marinas in Scotland were surveyed for the presence of seven non-native species, known to occur at other locations within the UK: the crustaceans Caprella mutica and Eriocheir sinensis, ascidians Perophora japonica and Styela clava, the green alga Codium fragile subsp. tomentosoides, and brown algae Sargassum muticum and Undaria pinnatifida. A variety of structures, including pontoon floats, chains and harbour walls were inspected to a depth of 0.5 m for the presence of these non-native species. Seven of the marinas had one or more of the target species. C. mutica was found at seven marinas; C. fragile subsp. tomentosoides at two marinas; S. muticum and S. clava were each found at a single marina; E. sinensis, P. japonica and U. pinnatifida were not found. The survey suggests that recreational boating is an important vector for the dispersal of marine non-native species, and that marinas may act as a refuge for such species. Further and regular port surveys throughout the UK are recommended to provide an effective early warning system for invasive non-native species.

To determine the importance of recreational boating as a vector for distributing marine organisms, including non-native species, the extent of hull fouling species on recreational yachts in Scotland was assessed. In August 2006, up to 100 yachts in each of the ten largest marinas in Scotland were ranked using a fouling index. 23 yacht owners were asked a questionnaire to determine the importance of general characteristics of the yacht and its travel history in relation to the level of hull fouling. 59 % of the yachts surveyed were found to have macrofouling attached to their hulls, suggesting that recreational boating has a high potential for distributing marine species throughout Scotland. Increased age of the antifouling paint, as well as long stationary periods and reduced sailing activity increase the risk of macrofouling species attaching to hulls. Recreational boating must be considered as a high risk vector for non-native species in Scotland.

In the mid 1980’s, the Australasian calanoid copepod Boeckella triarticulata was found in fish ponds of Northern Italy, representing the first record of this species for Europe. Its occurrence has not been reported for other Italian localities since 2005, when several specimens were found in the summer zooplankton of the Po River. It seems likely that B. triarticulata could be more widespread in the Po River valley than available distributional data suggest, considering both the scarcity of studies on the plankton of the main river channel and its adjacent water bodies as well as the high ecological plasticity of this centropagid species. The occurrence of this non-indigenous species in Italian waters may depend on the establishment of stable populations or on multiple reintroductions. Its threat as an invasive species is discussed on the basis of our preliminary results and from literature review.

The faunistic analysis of benthic samples taken from 0 to 200 m depths on the eastern Levantine coast of Turkey in September 2005 yielded the presence of 16 serpulid species, 9 of which are considered to be aliens: Hydroides brachyacanthus, H. diramphus, H. elegans, H. heterocerus, H. homoceros, H. minax, H. operculatus, Pomatoleios kraussii and Spirobranchus tetraceros. Ten species are new records for the Levantine coast of Turkey. Hydroides operculatus and P. kraussii formed dense populations on shallow-water artificial and natural hard substrates in the area. The population density and biomass (wet weight) of H. operculatus reached up to 384,000 individuals.m^-2 and 245.76 g.m^-2 in Mersin Bay and those of P. kraussii up to 52,000 individuals.m^-2 and 154.76 g.m^-2 in Iskenderun Harbour. The species with the highest frequency values at shallow water stations (0-5 m) were P. kraussii (50%), Pomatoceros lamarckii (50%), H. minax (42%), H. brachyacanthus (38%) and H. elegans (29%). Alien species were not found at depths deeper than 25 m. Alien species accounted for more than 85% of the serpulid specimens collected. Brief descriptions of the species, and their distributional, reproductive and ecological characteristics are given. In addition, population characteristics of the dominant species, H. operculatus and P. kraussii, are analyzed.

The occurrence of the alien species Chrysallida micronana [nom. nov. for Chrysallida nana (Hornung and Mermod, 1924) not Adams, A., 1861] (Gastropoda: Pyramidellidae) in the Mediterranean was investigated. In studies performed between 1997 and 2000, a total of 6 specimens were encountered from the Turkish coast of the Levantine and Aegean Seas. Descriptions of morphological features of the shell, along with the ecological and distributional aspects of the species are provided.

More than 140 aquatic alien species (AAS) have been reported from coastlines of the North Sea and the Baltic Sea and from inland waters within the national borders of Germany. The majority of these species has established self-sustaining populations. The most important vectors of introduction are shipping, species imports for aquaculture purposes and species imports as part of the ornamental trade. Several AAS have reached German waters via shipping canals. Many species show a locally limited distribution, but almost half of all AAS have spread successfully across larger areas. Several introduced species are abundant and approximately 20 % of all AAS in Germany can be considered as invasive. Prime source regions are the north-western Atlantic, the Indo-Pacific, and the Ponto-Caspian region. For all source regions considered, the invasion rate has been increasing since the end of the last century.

The introduction of the American ctenophore Mnemiopsis leidyi to the Black Sea was one of the most dramatic of all marine bioinvasions and, in combination with eutrophication and overfishing, resulted in a total reorganization of the pelagic food web and significant economic losses. Given the impacts this animal has exhibited in its invaded habitats, the spread of this ctenophore to additional regions has been a topic of much consternation. Here, we show the presence of this invader in estuaries along the Netherlands coast, based both on morphological observation and molecular evidence (nuclear internal transcribed spacer region 1 [ITS-1] sequence). Furthermore, we suggest the possibility that this ctenophore may have been present in Dutch waters for several years, having been misidentified as the morphologically similar Bolinopsis infundibulum. Given the level of shipping activity in nearby ports (e.g. Antwerp and Rotterdam), we find it likely that M. leidyi found its way to the Dutch coast in the ballast water of cargo ships, as is thought for Mnemiopsis in the Black and Caspian Seas. Given the magnitudes of the impacts this ctenophore has shown in its native and introduced ranges, the animal’s potential effects on the North Sea pelagic ecosystem and fisheries warrant close observation in the coming years. The development of large ctenophore aggregations during recent years was probably driven by the higher than average sea surface temperatures in the North Sea, and we hypothesize that populations from the southern North Sea may have been the source of the invaders reported in the Baltic Sea and the Skagerrak. If these northern populations (Baltic, etc.) are not able to over-winter, it is possible that established populations in southern North Sea estuaries may serve as a yearly supply of invaders to the colder waters to the north.

The North American freshwater sunfish, Lepomis gibbosus (Centrarchidae), was found in a pond outside Oslo, Norway in October 2005. The large number of fish (>100) in the pond suggests successful reproduction. Two monogenean parasites, non-native to Norway, were found on the gill filaments of the fish. The origin of the fish and associated parasites is not known.

New populations of Dreissena polymorpha have been found in Tuscany in both 2003 and 2005. These findings indicate that the spread of D. polymorpha is still in progress and that this invasive mollusc continues to colonise Italian river basins.

The majid crab Hyastenus hilgendorfi is one of the rarest Erythrean alien decapod species in the Mediterranean, with just two records off the Israeli coast in 1960 and 1977. On 21 September, 2004 it was collected again from the central Mediterranean coast of Israel.

A bilaterally ablated female banana prawn, Fenneropenaeus merguiensis, collected in the Bay of Iskenderun, southeastern Turkey on 6 October 2006, is likely an escape or an inadvertent release from an aquaculture facility. Because of the high permeability of aquaculture facilities, all introductions should be administered as to avoid unintentional releases or escapes into the wild.

Following the recent occurrence of Lagocephalus sceleratus (Gmelin, 1789) in the Mediterranean Sea, our findings reveal that the species is now very common along the Levant coasts of Turkey. A specimen was recently captured in Izmir Bay (Aegean Sea), representing its north-westernmost occurrence in the Mediterranean. The species has a potential risk to humans, since it contains tetrodotoxin (TTX) that maybe a source for food poisoning.

Siphonaria belcheri and Septifer bilocularis were reported from Iskenderun Bay in 2001. But they were considered as misidentifications of Siphonaria crenata and Septifer forskali respectively, in the CIESM Atlas of Exotic Species. The present study, carried out in 2005-2006, indicates the presence of these two alien molluscs in Iskenderun Bay, Turkey.

The invasive ctenophore Mnemiopsis leidyi has been detected during late summer and autumn 2006 in northern Europe. So far it has been found in the southern North Sea area, along the Swedish west coast, in the southwestern Baltic and along the south and southwestern Norwegian coasts. From the large populations observed, it is obvious that it must have been introduced before 2006, but remained unrecorded until this autumn.

The invasive ctenophore Mnemiopsis leidyi was first recorded in the Kiel Bight (western Baltic Sea) on 17 October 2006 during a regular weekly sampling program. The M. leidyi abundance gradually increased from 29.5±12.7 ind.m^-3 in mid-October to 92.3±22.4 ind.m^-3 in late November 2006. The occurrence of M. leidyi in the Baltic Sea is of great concern as this invader has caused negative impacts in the southern seas of Europe.