The recent detection of the invasive colonial tunicate Diplosoma listerianum in Havre- Aubert, Magdalen Islands (Quebec, Canada) in 2008, prompted the development of a molecular assay as a method to detect and monitor for the potential invasion of this species in Prince Edward Island. The aim of this study was to design a highly sensitive, species-specific Polymerase Chain Reaction (PCR) assay capable of detecting D. listerianum with a high efficacy in local water samples. To accomplish this, oligonucleotide primer sets were designed from the 18S rDNA gene of D. listerianum. Primer sets were evaluated for specificity using the GenBank database, followed by a series of spiked water sample trials involving various tunicate species. Assay efficacy was tested and then evaluated by conducting spiked water sample trials using D. listerianum samples from two different geographic locations (Japan and Canada). Primer sets that were shown to be species specific were then tested for their analytical sensitivity and environmental efficacy by spiking local water samples with various amounts of D. listerianum tissue. The primer set DlistF1/DlistR1 was found to be species specific and yielded no false positive results when tested with tissue from the four invasive tunicate species currently present on Prince Edward Island (PEI) (Styela clava, Botryllus schlosseri, Botrylloides violaceus, and Ciona intestinalis). This assay was also capable of detecting D. listerianum DNA from two different populations, demonstrating its potential for use in other geographic locations, which may possess different haplotypes of the species. As the results of this study demonstrate, the DlistF1/DlistR1 assay has a high analytical sensitivity, detecting DNA from as little as 1 zooid in a water sample, and was not inhibited when tested with water samples collected from various bays across both PEI and the Magdalen Islands. The DlistF1/DlistR1 molecular assay provides a monitoring tool for shellfish aquaculture regions and can be used to facilitate early detection of this species. This level of early detection is beneficial to facilitate the implementation of mitigation programs in time to prevent D. listerianum from reaching nuisance levels.

Three apparently non-native species of Bugula occur in marinas and harbours in Atlantic Europe. The most common, B. neritina, was known from a few sites in southern Britain and northern France during the 20th century, following its discovery at Plymouth by 1911. During the 1950-60s it was abundant in a dock heated by power station effluent at Swansea, south Wales, where it flourished until the late 1960s, while water temperatures were 7-10°C above ambient. It disappeared after power generation ceased, when summer temperatures probably became insufficient to support breeding. Details of disappearances have not been recorded but B. neritina was not seen in Britain between c1970 and 1999. Since 2000, it has been recorded along the south coast of England, and subsequently in marinas in the southern North Sea, Ireland and southern Scotland, well to the north of its former range, as well as along the Atlantic coast from Spain to The Netherlands. It has also been introduced to outlying localities such as the Azores and Tristan da Cunha. We report that this rapidly spreading form has the same COI haplotype as B. neritina currently invasive elsewhere in the world. B. simplex has been reported less, with 1950s records from settlement panels in some Welsh docks. It has not been targeted in most recent marina surveys but has been observed in southwest England, Belgium and The Netherlands. There are almost no recent records of B. stolonifera, though it was probably introduced to a few British and Irish ports prior to the 1950s. Its current status in most of western Europe is unknown but it has been reported as expanding throughout most of the world during the last 60 years. Having poorly known distributions, B. simplex and B. stolonifera should be recorded during future monitoring of alien species in Atlantic Europe. Illustrations to aid identification are included for all three species.

The aim of this paper is to present the distribution of the non-native species Hypania invalida (Polychaeta) within Serbian waters. In 1971, this species was found for the first time in the Danube and the Sava Rivers. According to our results, H. invalida is now widespread within potamon-type rivers that are under the influence of hydromorphological alterations and exposed to intensive ship traffic. The distribution of this polychaete species, as well as some other alien aquatic invertebrate taxa Branchiura sowerbyi, Chinese pond mussel Anodonta woodiana, Spiny cheek crayfish Orconectes limosus and Asian clam Corbicula fluminea, further indicates that heavily modified waterways are suitable recipient areas for species introduction and adaptation.

During a study carried out in spring-summer 2010, the invasive Ponto-Caspian polychaete Hypania invalida (Grube, 1960) was recorded for the first time in the southern part of the River Odra estuary (southern Baltic). This is the first record of this species in Poland or in any a Baltic estuary. The appearance of H. invalida in the Odra estuary coincided with flood water descent in the Odra, suggesting that floods can aid in dispersal of this polychaete.

First detected in the United States in Idaho's Snake River in 1987, the New Zealand mud snail (NZMS), Potamopyrgus antipodarum, was discovered in Olympia Washington’s Capitol Lake in 2009. The snail is not native to North America and may be capable of adversely impacting native species diversity and food web dynamics in aquatic ecosystems. In this study, we evaluated the effect of lowering the lake level during freezing weather on the survival of NZMSs. Both generalized linear models with link function logit and nonlinear mixed effects models were used to investigate the rates of detection and survival with four temporal and environmental predictor variables. The rate of detection of NZMSs was affected by substrate depth and proximity to shore. The location of sample stations (upshore versus offshore), substrate depth, and elapsed time between collection from the field and laboratory processing did not affect survival rates. The survival rate of NZMSs decreased rapidly with time and the predicted survival rate at the conclusion of the freezing episode was 1.8%. The results indicate that lowering the water level during freezing weather can be a highly effective means for controlling the distribution and abundance of NZMSs and reducing the risk of their spread to other water bodies.

The parthenogenetic marbled crayfish, Marmorkrebs, has high potential to become an invasive species because single individuals can establish a population. Marmorkrebs have already been introduced in several countries, have successfully established populations in at least two of them, and are rapidly expanding in one case (Madagascar). To assess the potential ecological threat arising from further Marmorkrebs introductions, we developed four species distribution models using the distribution of Procambarus fallax (the sexual form of Marmorkrebs) and exotic populations of Marmorkrebs in Madagascar and Europe. The models were applied to three regions where Marmorkrebs pose a conservation concern: Madagascar, where Marmorkrebs populations are growing; Europe, where individuals have been found repeatedly, and where some Marmorkrebs populations are becoming established, and; North America, where Marmorkrebs are sold as pets, which presents a risk of introduction into North American ecosystems. All models predicted that eastern Madagascar provides suitable habitat for Marmorkrebs. Most models suggested that relatively small areas of Europe are suitable habitat, although a model that includes locations of Marmorkrebs introductions in Europe predicts much of Europe could be suitable, which is supported by recent discoveries of populations in Germany. All models predicted that the south eastern United States, Cuba, and much of Mexico are also potential habitats. The climatic variable with the greatest predictive power was precipitation in the warmest quarter, which may reflect a susceptibility to drought that has been documented for P. fallax.

Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known wild populations of Asian swamp eels present in the continental United States. This paper presents results of a pilot study intended to gather baseline data on the occurrence and abundance of internal macroparasites infecting swamp eels imported from Asia to North American retail food markets. These data are important in assessing the potential role that imported swamp eels may play as possible vectors of non-native parasites. Examination of the gastrointestinal tracts and associated tissues of 19 adult-sized swamp eels—identified as M. albus “Clade C”—imported from Vietnam and present in a U.S. retail food market revealed that 18 (95%) contained macroparasites. The 394 individual parasites recovered included a mix of nematodes, acanthocephalans, cestodes, digeneans, and pentastomes. The findings raise concern because of the likelihood that some parasites infecting market swamp eels imported from Asia are themselves Asian taxa, some possibly new to North America. The ecological risk is exacerbated because swamp eels sold in food markets are occasionally retained live by customers and a few reportedly released into the wild. For comparative purposes, M. albus “Clade C” swamp eels from a non-native population in Florida (USA) were also examined and most (84%) were found to be infected with internal macroparasites. The current level of analysis does not allow us to confirm whether these are non-native parasites.

The largest known infestation of alligator weed Alternanthera philoxeroides (Mart.) Griseb. in Victoria, Australia, was reported in January 2009 in an urban pond. To determine how long the infestation had been present, high quality digital aerial images (orthophotos) were gathered for the site. Since all infestations are subject to ongoing eradication programs in Victoria, historical orthophoto records provide a unique opportunity for retrospective analysis, to calculate and report on the uncontrolled growth of aquatic alligator weed. Using geographic information system software (GIS), orthophotos were visually assessed to delineate the area of infestation for each year, from which annual increases in area were calculated. The infestation increased in area from ca. 0.029 ha in December 2004 to ca. 0.73 ha in December 2009, to cover 33% of the 2.2 ha water body. The annual area expansion was 200% for the first year of record. This reduced each year, to 22% at the end of the five year period. The mean lateral rate of expansion for floating alligator weed over the five years was 4.3 m (SD 2.2) annually. The average biomass of alligator weed at the site in summer 2010 was 4.9 kg dry weight m^-2. Using the area of infestation from the December 2009 orthophoto the total estimated biomass in the pond equated to 35.6 tonnes dry weight.

A population of Ludwigia grandiflora, an aquatic weed from South America, has been recorded in the North West of Germany near Leer, Lower Saxony in an old branch of the River Leda, a tributary of the River Ems. This species is new to the German flora. After an initial observation of only a few individuals in 2004, a dense growth of L. grandiflora has been observed from 2009 onwards. An ecological risk assessment, mainly based on knowledge about invasion histories in neighbouring countries, showed that this species is a threat to German biodiversity; thus, it is considered to be invasive and has been assigned to the German Black List. In accordance with nature conservation efforts, management policies are being developed by the appropriate authority to eliminate the population.

The Laurentian Great Lakes have been successfully invaded by at least 182 nonindigenous species. Here we report on two new species, water hyacinth Eichhornia crassipes and water lettuce Pistia stratiotes, that were found at a number of locations in Lake St. Clair and Detroit River during autumn 2010. Both species are commonly sold in the water garden and aquarium trade in southern Ontario and elsewhere. While it is not clear whether these species are established or can establish in the Great Lakes, the historic assumption that neither of these subtropical to tropical plants pose an invasion risk must be questioned in the light of changing environmental conditions associated with climate warming that may render Great Lakes’ habitats more suitable for these species and increase the likelihood of their successful establishment.

Bellamya chinensis, an Asian species, is reported for the first time from the Netherlands. These records are also the first reports from Europe. The species is commercially sold for garden ponds and aquaria, from which they may have escaped or been released. It is anticipated that this species will become invasive in the Netherlands and beyond.

The amphipod Melita nitida Smith, 1873 is indigenous to the Atlantic coast of North America and so far has only been recorded as non-native species from the Pacific coast of North America and estuarine waters in The Netherlands. We detected a few specimens in the mesohaline part of the Kiel Canal (Germany) which showed considerable variation of some morphological characters. Transport in ballast water and in fouling on ships hulls seem to be the most likely introduction vector. A successful establishment of new populations of M. nitida in the Kiel Canal, other German estuaries or even the Baltic Sea cannot be excluded.

Procambarus clarkii is among the worst invasive species that have invaded Europe. It originates from the central south of the USA and northeastern Mexico and is a hardy, r-selected generalist. There exists a marked gradient in population numbers from southwestern to northeastern Europe: The Iberian Peninsula, Italy and France have the bulk of the populations, while northeastern populations are mainly scattered and isolated from each other. In the present study I report on the distribution of P. clarkii in an artificial lake system along the River Danube in Southwestern Germany, which is within its northeastern range limit. The presence of P. clarkii was confirmed in nine lakes and one canal with stagnant water. Procambarus clarkii was absent from lotic situations, which may indicate that P. clarkii thrives chiefly in stagnant or slow flowing waters. A probable explanation is that those habitats heat up faster and reach higher summer temperatures than most lotic habitats. Since P. clarkii is considered as a `warm water´ species, lentic habitats probably offer more favorable temperatures. The populations form two disjunct distribution centres, isolated from each other by around seven km linear distance. It is not known for sure when the species was initially introduced, but it may have been present in the western distribution centre since the mid 1970s. The emerging disjunct distribution pattern is a synergistic result of introductions into two lakes and subsequent active spread to surrounding habitats, including migration overland. Procambarus clarkii numbers are often high and the species has become a nuisance to recreational fishery, since it tends to grab on to exposed fish bait. Two noble crayfish (Astacus astacus) populations were wiped out rapidly by P. clarkii, presumably due to crayfish plague transmission. Although eradication may prove impossible, population management, e.g. intense trapping and stocking of predatory fish, is strongly suggested. Early eradication, if necessary relying on extreme control methods (e.g. chemical agents), should be attempted when P. clarkii invades further lakes.

A specific marine biological data management tool, the Black Sea Mnemiopsis leidyi database system was created within the European Commission 6th framework Black Sea SCENE project for the Black Sea region and is now being supported by the Permanent Secretariat of the Black Sea Commission. The core team of scientists studying M. leidyi in the Black Sea was brought together and all their available M. leidyi data and metadata were loaded into the common database. This works on the Internet and has a simple user interface. It gives Black Sea scientists the option to load all their corresponding data on the database and to use it as an effective tool to work both with M. leidyi and, in future, with other gelatinous organisms’ data, including another invasive ctenophore Beroe ovata. All loaded metadata and historical data are available to the entire scientific community. More recent data are available to the team members and with some restrictions – to other scientists.