The zebra mussel, Dreissena polymorpha (Pallas 1771), invaded Lough Sheelin in the midlands of Ireland in 2001. In order to assess the status of the mussel population in the lake, the distribution, extent of colonisation, abundance, biomass and sizefrequency structure of post-settlement stages were studied in 2005 and 2006. In addition, changes to water quality parameters in the lake post-establishment were assessed with reference to the pre-invasion period. Zebra mussels were found throughout the lake at most sites on all main categories of substrates examined (stony and soft substrate; submerged vegetation: Characeae, Elodea spp., Cladophora spp., Potamogeton spp. and Myriophyllum spp., and emergent vegetation: Phragmites australis and Schoenoplectus lacustris). Overall, increases in density and biomass of mussels were recorded from 2005 to 2006. Analysis of physiochemical data show a reduction in chlorophyll a with an increase in water transparency, however the total phosphorus concentration remains high. This paper highlights the common misconception that zebra mussel introductions lead to overall improvements in water quality.

The aim of this study was to reveal the taxonomic diversity of algae that colonize the shells of zebra mussels, Dreissena polymorpha, in mesotrophic Lake Naroch (Belarus). In total, 155 algal species have been identified in collected samples, with Bacillariophyta, Chlorophyta and Cyanophyta being the most common divisions. The species richness of phytoperiphyton from Dreissena shells appeared to be much higher than that of phytoplankton (30 species found). Taxonomic diversity of the phytoperiphyton was found to significantly decline with depth, which we explain by decreasing sun irradiance. In contrast to depth, the length of Dreissena shells did not demonstrate any relationships with the composition of algal communities.

Three different river sizes were examined at various distances downstream of Irish lakes containing zebra mussel populations.The larger rivers contained zebra mussel larvae and adults at a wide range of densities throughout their length. However, smaller rivers demonstrated a rapid decline of larvae and adults with progression downstream. River sections downstream of interconnected lakes were also examined as part of this study. The fate of the zebra mussel larvae in medium and small rivers remains unknown.

The zebra mussel (Dreissena polymorpha) is an abundant and invasive molluscan shellfish species which arrived in Ireland’s river basins in the early 1990’s. Inland and coastal surface waters can be contaminated by human waterborne zoonotic enteropathogens such as Cryptosporidium parvum, Giardia lamblia, Encephalitozoon intestinalis, E. hellem and Enterocytozoon bieneusi originating predominantly from wastewater treatment plant effluents and agricultural runoff. Bivalve species, i.e., the invasive zebra mussel, Mytilus edulis (blue mussel) and Anodonta anatina (duck mussel) were used as sentinels and also as biomonitors of the aforementioned waterborne pathogens at twelve sites located in three Irish river basin districts impacted by pollution related to various water quality pressures. A variety of advanced biomolecular techniques were utilized to assess the presence and concentration of these pathogens in molluscan shellfish. At least one pathogen species was detected in bivalves at each of the twelve sites. Cryptosporidium, implicated in several recent Irish gastrointestinal epidemics, was recorded at all sites subjected to agricultural runoff and at one treated wastewater discharge site, linking source-track directly to animal and human fecal wastes. Overall, the results demonstrated a long-term human enteropathogen contamination of Irish waters with consequent public health risk-factors for drinking water abstraction and water-based recreational activities. The study provided further solid evidence that zebra mussels can recover and concentrate environmentally derived human pathogens and therefore can be used for the sanitary assessment of surface water quality.

Dreissena polymorpha (zebra mussel) has been invading freshwater bodies in Europe since the beginning of the 19th century and is still doing so. The zebra mussel was introduced in the Iberian Peninsula in 2001, and since then the Ebro Hydrographic Confederation has adopted several measures to stop the invasion. The main invasion route for the zebra mussel in Spain is via recreational boating in lakes and reservoirs, so the main measure adopted has been to change the navigation rules in the Ebro basin. Restrictions on the number of navigable reservoirs and the introduction of disinfection protocols and access controls have helped to prevent the spread of the zebra mussel.

The invasive false mussel, Mytilopsis adamsi Morrison, 1946 (Bivalvia: Dreissenidae), is a brackish water bivalve, native to tropical West Pacific coast of central America. The species has now become established in East Asian, South Asian and Southeast Asian countries. Species spread has been especially rapid with its distribution now including the lower part of the Gulf of Thailand. This is the first report of the establishment of this species in the lower part of the Gulf of Thailand, in Haad-kaew Lagoon and Thale Sap Songkhla, in Songkhla province, and the Pak Phanang Estuary in Nakhon Si Thammarat province, south Thailand. Descriptions of its morphology are consistent with previous descriptions from other areas as M. adamsi. Based on the available evidence, it is postulated that the species was transported to the areas between the year 1990 and 2000 via international commercial cargo ships. These findings indicate that the spread of M. adamsi is still in progress and that this invasive mussel continues to colonize the Songkhla Lagoon System.

The purple dye murex Bolinus brandaris (Linnaeus, 1758) has been reported for the first time from O Grove inlet (Galicia, NW Spain) in 2007. The presence of the shell mounds shows that this Mediterranean gastropod is commonly recorded in O Grove inlet together with another exotic muricid: Hexaplex trunculus. To the extent of our knowledge, this is the northernmost record of this species on the NE Atlantic coast. This species is the newest entry into a list of 23 aquatic and benthic exotic molluscs species from Galician waters. Most of them are introduced marine species, which arrived accidentally, or not, in the Galician region as a consequence of ship transport, shellfish culture and trade.

This is a brief review of present invasion history of the New Zealand mud snail (Potamopyrgus antipodarum) within the Azov-Black Sea Region. The most recent locations of P. antipodarum expansion within the Azov-Black Sea Region (lower parts of the Danube, Dniester, and Don basins, small steppe rivers and streams) are described.

Potamopyrgus antipodarum (Gastropoda: Hydrobiidae), a New Zealand native species, is recorded for the first time in waterbodies of Greece, being dominant in the gastropod fauna present; waterfowl transportation is suggested as its invasion mode. This species was collected (November 2007) from the aquatic plants Myriophyllum spicatum and Nasturtium officinale in Lake Trichonis (CW Greece) and an adjacent stream. Totally, 332 individuals of various ages were recorded, females being the majority. One diatom (Cocconeis placentula var. euglypta) was found in its digestive tube, also thriving abundantly on the surface of both the invader shell and the aquatic plants, and in association with other cosmopolitan periphytic diatoms (three of them new for the area, with one new record for Greece) or endemic diatoms.

In 2008, the New Zealand mud snail Potamopyrgus antipodarum was detected in artificial freshwater lakes of Kalinigrad City (Russia), developed in sand and gravel extraction sites. P. antipodarum records along the Baltic coast were previously located in open sea and estuary sites and this is first species’ record, in this type of man-made freshwater habitat, for the Baltic Region.

The New Zealand mud snail Potamopyrgus antipodarum (Gray, 1843) is a common invasive species in fresh and brackish water ecosystems in Europe, Australia, Japan, and North America. In some invaded habitats, P. antipodarum can reach high densities (over 500,000 snails m^-2) and dominate the biomass of the benthos, leading to detrimental impacts to native biota and changes in ecosystem dynamics. We report the previously unpublished occurrence of P. antipodarum in thirteen fresh and brackish water systems adjacent to the Pacific coast of North America including a new northern range for P. antipodarum: Port Alberni, Vancouver Island, British Columbia, Canada (49.2479º, -124.8395º). We hypothesize the snail was spread from the Columbia River Estuary to Port Alberni via recreational watercraft or infected fishing equipment. Its discovery in Port Alberni reveals the potential for other aquatic nuisance species in the lower Columbia River to spread to British Columbia. Resource managers on the Pacific coast should remain vigilant and educate the public to prevent the further spread of the P. antipodarum as well as other aquatic invaders.

This paper presents an overview of the chronology of Asian clam Corbicula fluminea invasions in the Iberian Peninsula and additionally presents the distribution of all relevant records published from 1981 (first record in the Peninsula) until 2008 in two geographic formats with references to invaded basins. In short, a total of six great basins and thirteen UTM 100x100 squares showed the presence of the species.

The North American gastropod Physella acuta (Draparnaud 1805) has been recorded for the first time in the Neman River basin, Belarus during a biological survey carried out on 23 August 2007. One specimen was found in a shallow water microhabitat (depth 0.2 m) amongst sand and mud. Most likely, this alien gastropod was introduced either by local aquarium keepers, or from Poland via the Augustov canal.