Search

Visual searches are a common method of detecting invasive species in coastal waters, but the statist ical properties of search methods have rarely been evaluated. Understanding the error rate (especially false negatives) and effective detection distance of searches can improve survey design, and quantify the uncertainty in risk assessments used to inform invasive species management efforts. An experiment using artificial tunicates (“decoys”) was conducted in Hillsborough Bay, Prince Edward Island, to determine the effectiveness of SCUBA divers conducting underwater visual searches for the vase tu nicate, Ciona intestinalis (Linnaeus, 1767). Single decoys and clusters of three decoys, constructed from water -filled, ivory-coloured balloons 5-6 cm in length, were placed at a blue mussel, Mytilus edulis (Linnaeus, 1758), aquaculture site on buoys, lines and mussel socks. The probability of detecting tunicate decoys on a mussel sock in the experiment is 89.8% (±SD 7.1), known in this paper as a true positive. The probability of not detecting tunicate decoys actually placed on a mussel sock in the experiment is 10.2% (±SD 7.1), known in this paper as a false negative. Divers detected 79.2% (±SD 7.1) of single decoys and 94.0% (±11.4) of clusters. Divers were able to detect single decoys from a measured horizontal distance of 2.7 m (±0.8), and clusters from 2.8 m (±0.9). The typical detection distance for real C. intestinalis estimated by divers was, on average, 2.1 m (range 1 - 3 m), and tunicates of lengths ≥ 2.9 cm (range 1-4 cm) could be detected.

This paper is the first in a three-part series that addresses rapid response as a management approach to the recurrent problem of colonization by non-indigenous species, invasive tunicates in particular. “Rapid response” refers to the steps taken, starting before detection of the invasion of a non-indigenous species, through a decision process that may culminate in an attempt to eradicate the species before it becomes established in the new habitat. Rapid response is the second line of defense against nonindigenous species, when prevention measures have failed. We review the goals of rapid response, and its history in the marine environment, to place rapid response into context for the subsequent papers which will review the history of non-indigenous tunicate management in Prince Edward Island, Canada, and propose a framework for rapid response.

The ability to conduct an effective rapid response to the detection of a novel non-indigenous species is greatly enhanced by the development of appropriate protocols and action plans before the arrival of species for which rapid response may be required. Worldwide, much effort has been expended on the development of such plans. Rapid response in Canadian waters is in its infancy and in Atlantic Canada, at least, rapid response against invasive tunicates has been carried out on an ad hoc basis in the absence of formal rapid response plans. Even so, many of the essential elements of a rapid response plan were implemented in the management of recent colonization of estuaries of Prince Edward Island (PEI) by non-indigenous tunicates. This paper proposes a framework that can be used to develop rapid response plans against future colonization of Canadian waters by nonindigenous species. The framework builds on principles derived from the preceding two papers that reviewed case histories of marine rapid response internationally and of four non-indigenous tunicates that have recently become pests in PEI estuaries. The status of non-indigenous tunicate management in PEI will be discussed with reference to the proposed framework in order to highlight areas where rapid response planning in Canada may benefit from further development.

Aquatic ecosystems are particularly vulnerable to introductions of non-indigenous species, which potentially lead to major disruptions in the functioning of these invaluable habitats. Despite the significance of aquatic systems, there is no collated data available on the aquatic non-native plants in Serbia. Consequently, the aim of this paper is to provide a first overview of the aquatic alien plant species recorded in Serbia, their origins, current distribution, habitat preferences and invasiveness status. This study comprises the results of a comprehensive literature review and extensive field research on lake and river systems over a nine year period (2007-2015), with the addition of data from the IASV database and Joint Danube Surveys 2 & 3. The results of this study show the presence of seven non-indigenous aquatic plant species in Serbia which, despite being a relatively low number when compared to France and Germany, is in line with most of the countries of the region (e.g. Croatia, Bulgaria and FYR Macedonia). The majority of the species are native to the Americas, which concurs with the results of previous studies at the European level, with only one species of Asian origin. The most abundant of the registered non-natives is Vallisneria spiralis, followed by Azolla filiculoides and Elodea nuttallii, while Cabomba caroliniana, as the newest registered aquatic alien in Serbia, has the least number of records. All of the registered non-natives predominantly occur in running waters, including as much as 91% of the records for Elodea canadensis and 85% for Elodea nuttalli. Vallisneria spiralis is present in five different EUNIS habitat types, while Paspalum distichum was recorded predominantly along the River Danube, thereby highlighting it as P. distichum's main corridor of spread in Serbia. The distribution of all the recorded non-indigenous species is primarily linked to the northern, low-lying part of Serbia-i.e. Vojvodina Province. Such a distribution pattern is concordant with the presence of adequate habitat types, the courses of potential international invasion corridors in the Sava and Danube rivers and the position of the elaborate irrigation canal network of the Danube-Tisa-Danube Hydrosystem; but also with the frequency of studies carried out in this region over the years. Of the seven aquatic aliens present in Serbian waterbodies, three are considered to be highly invasive and one potentially invasive, while two have also been included in the list of 150 most widespread alien species in Europe.

An estimated 60– 75% of the world’s infectious diseases of humans are zoonotic, infecting both humans and other animals. Many are vectorborne, relying on transmission by mosquitoes and biting flies that are aquatic for much of their lifespan. Others rely on aquatic molluscs, fishes, or other aquatic animals for completion of their transmission cycles, and others develop and thrive in diverse freshwater environments outside any host. While such diseases remain firmly endemic in many areas, new outbreaks of infectious diseases associated with freshwater have occurred throughout the world, and many others have spread to new locations. This may involve introduction of aquatic vectors into locations where the disease was previously unknown, as in the recent occurrences of mosquito-transmitted diseases such as West Nile Virus in North America, dengue fever in southern Europe, Chikungunya virus in the Caribbean and South America, and dirofilariasis in Central and Eastern Europe. Such a pattern is also possible with such major human pathogens as Schistosoma blood flukes and food-borne trematodes, through introduction of aquatic host snails from long-established foci in other areas. Alternatively, waterborne pathogens may be introduced directly, leading to disease outbreaks such as the cholera disaster still unfolding in Haiti. Accidental or intentional introduction of pathogens or their aquatic vectors and hosts are among the primary concerns that affect international trade, travel, and global health security. These concerns are compounded by the prospect of warming climate, potentially resulting in primarily tropical diseases encroaching into historically subtropical or temperate regions. Thus, we must be prepared for the possibility of geographic spread of diseases into areas where they have not occurred, or reintroduction into areas where they once occurred but have been eliminated through control measures. For example, North America and Europe are at risk for reintroduction of such major “tropical” diseases as malaria and yellow fever, and thus must come under increasing scrutiny, starting with surveillance of freshwater systems for both established and potentially invasive vector and host populations. This critical perspective paper briefly reviews selected previous cases in which aquatic invasive species have contributed to infectious disease emergence, re-emergence, or increase, and proposes One Health strategies for integrating human, animal, and environmental monitoring and surveillance to better prepare for or prevent geographic spread of major human health threats associated with aquatic systems.

The introduction and spread of non-native species is one of the least reversible human-induced global changes. In South Africa, non-native fish introductions have occurred over the last two and a half centuries. Resultant invasions have been cited as a primary threat to imperilled South African fishes and other aquatic fauna. Addressing a problem of this magnitude requires an organised approach. The aim of this paper is to summarise the current knowledge, risk and ecological impacts associated with non-native freshwater fish introductions in South Africa. A total of 55 fishes have been introduced into novel environments in South Africa. Of these, 27 were alien and 28 were extralimital

This paper represents the first attempt to study the microfungal flora contained in the digestive system of the most widespread aquatic invasive invertebrate in the world: Procambarus clarkii (Cambaridae, Decapoda). Understanding its bioinvasion, in terms of ecological risk and environmental impact, requires a multidisciplinary approach that considers consequences on all levels, from macroscopic to microscopic. In this study, we investigated both the population dynamics and the dietary habits of the red swamp crayfish captured within a natural biotope in Northern Italy. The diet was mainly based on plant detritus. The analysis of microfungal flora in the crayfish stomach revealed a fairly constant composition, unrelated to season and diet. Since most of the fungi were associated with detritus and some species were particularly frequent, we formulate the hypothesis that the fungi may be selected to decompose plant material in the digestive tract, thus providing a source of energy to the crayfish. Procambarus clarkii is also shown to be a potential vector of plant diseases as some of the 45 isolated fungal taxa are potentially phytopathogenic.

After going unreported in the northwestern Atlantic Ocean for 18 years (1988 to 2006), the Asian tiger shrimp, Penaeus monodon, has recently reappeared in the South Atlantic Bight and, for the first time ever, in the Gulf of Mexico. Potential vectors and sources of this recent invader include: 1) discharged ballast water from its native range in Asia or other areas where it has become established; 2) transport of larvae from established non-native populations in the Caribbean or South America via ocean currents; or 3) escape and subsequent migration from active aquaculture facilities in the western Atlantic. This paper documents recent collections of P. monodon from the South Atlantic Bight and the Gulf of Mexico, reporting demographic and preliminary phylogenetic information for specimens collected between North Carolina and Texas from 2006 through 2012. The increased number of reports in 2011 and 2012, ranging from 102 mm to 298 mm total length, indicates that an adult population is present in densities sufficient for breeding, which is indicative of incipient establishment. Based on these reports of P. monodon, its successful invasion elsewhere, and its life history, we believe that this species will become common in the South Atlantic Bight and Gulf of Mexico in less than 10 years. Penaeus monodon is an aggressive predator in its native range and, if established, may prey on native shrimps, crabs, and bivalves. The impacts of an established P. monodon population are potentially widespread (e.g., alterations in local commercial fisheries, direct and indirect pressures on native shrimp, crab and bivalve populations, and subsequent impacts on the populations of other predators of those organisms) and should be considered by resource managers. The impacts of P. monodon on native fauna and the source(s) or vector(s) of the invasion, however, remain unknown at this time.

Predicting and averting the spread of invasive species is a core focus of resource managers in all ecosystems. Patterns of invasion are difficult to forecast, compounded by a lack of user-friendly species distribution model (SDM) tools to help managers focus control efforts. This paper presents a web-based cellular automata hybrid modeling tool developed to study the invasion pattern of lionfish (Pterois volitans/miles) in the western Atlantic and is a natural extension our previous lionfish study. Our goal is to make publically available this hybrid SDM tool and demonstrate both a test case (P. volitans/miles) and a use case (Caulerpa taxifolia). The software derived from the model, titled Invasionsoft, is unique in its ability to examine multiple default or user-defined parameters, their relation to invasion patterns, and is presented in a rich web browser-based GUI with integrated results viewer. The beta version is not species-specific and includes a default parameter set that is tailored to the marine habitat. Invasionsoft is provided as copyright protected freeware at http://www.invasionsoft.com.

Similar to the zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena bugensis), the Asian clam (Corbicula fluminea) is an invasive bivalve that has colonized many waterbodies in the United States and Europe. So far, low water temperature and ice formation during winter appear to have limited its northern distribution, especially in Eastern North America. This paper documents the recent discovery of a Corbicula fluminea population in the St. Lawrence River, in the thermal plume produced by the Gentilly-2 nuclear power plant (Becancour, Quebec, Canada). Based on a benthic samples obtained during November 2009 from 21 sites, both upstream and downstream of the power plant outlet, average density (± standard error) of this non-indigenous species was 368 ± 176 living individuals/m². Additional samples collected in 2010 showed an increase in density to 3,380 ± 1,315 living individuals/m² downstream the power station, and established the range limit at 4 km downstream. The species was present only downstream of the power plant and its distribution appears to be associated with the warm water plume. The influence of the thermal plume at 4 km from the power station was however fairly limited. The size of individuals varied from < 1 mm to 24 mm in length. These results confirm the establishment of the species in the St. Lawrence River, thereby extending the northern boundary of its distribution in North America.

The occurrence of the non-indigenous species Limnoperna securis belonging to Mytilidae family is recorded for the first time in the Bay of Biscay. Numerous individuals were collected in intertidal and shallow waters in the inner part of Nervion estuary (Bizkaia, Basque Country, SE Bay of Biscay). In the present paper, notes about the history of this small brown mussel invasion, vectors of

The Asian clam Corbicula fluminea was first discovered in Ireland in the Rivers Barrow and Nore in 2010. Scuba diving surveys were the primary sampling method used to determine the detailed distribution of this species in the two rivers. Sustainable populations of Asian clam were present in the tidal freshwater reaches of both rivers. No clams were present upstream of the tidal limit. A maximum density of 9,636 individuals m -2 was recorded in the River Barrow. This paper presents some basic metrics in relation to the populations present in these two connected river systems.

Editor’s note: This paper was prepared by participants attending the workshop entitled “Quagga Mussels in the Western United States – Monitoring and Management” held in San Diego, California, USA on 1-5 March 2010. The workshop was organized within the framework of the National Shellfisheries Association, American Fisheries Society (Fish Culture Section) and World Aquaculture Society’s Triennial Conference. The main objective of this workshop was to exchange and share information on invasive quagga mussels among agencies. The data presented in this special issue provide critical baseline information on quagga mussel monitoring and management at the early stages of introduction in the western United States.

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 paper presents the first European records of the copepod (Crustacea, Calanoida, Diaptomidae) Skistodiaptomus pallidus in shallow eutrophic waters indirectly connected with the Weser River, Northern Germany. Its original distribution is in the Mississippi basin of the United States of America. It is probable that this species entered the Weser River via ship ballast.

Cyprinus carpio is known to be established in most of Mexico. Only the Mexican Gulf states were free of this species until recently. This paper reports the first record of the common carp in Tabasco, Mexico. Seven specimens of Cyprinus carpio var. communis and one specimen of Cyprinus carpio var. specularis were detected in a small scale fishing landing site near Frontera, Tabasco on January 24, 2011. Further sampling and monitoring is required to assess the ecological impacts of this exotic species on the native fauna.

This paper is the first attempt to compile a list of the non-indigenous aquatic invertebrate species currently known to occur in the Ebro River basin (Northeast Spain). A total of 23 exotic aquatic species have been recorded in this area, and one more (the branchiobdellida Xironogiton victoriensis) may also be present in this Iberian basin. Due to the negative impacts that biological invasions cause to ecosystems and to human activities, it is important to state the introduction pathways and prevent the spread of already introduced species. In order to fight against biological alien species invasions, development of national strategies on invasive alien species and international cooperation are considered essential.

Dreissena polymorpha has invaded seven rivers in the Ebro River basin (Spain) in the period 2001-2009. In this paper, we present a compilation of management strategies directed by the Ebro Hydrographic Confederation (CHE) with the aim of showing the different steps taken by this organisation to prevent the spread of this invader. These practical procedures are accompanied by diverse educational materials to inform and make people aware of the importance of this problem. The experience gained during these years has allowed the establishment of both an adequate sampling schedule and a sampling method for larval monitoring with the purpose of detection of zebra mussel populations. On the other hand, we have observed that mechanical cleaning and drying techniques are the physical control methods most frequently used by affected users in the Ebro basin, with use of chlorine as chemical method.

The Iberian Peninsula contains a highly endemic freshwater ichthyofauna that is being homogenized and threatened by an increasing number of non-native fishes. Here, in this paper, I reviewed the literature on the impacts of fish introductions and translocations on the native Iberian ichthyofauna. The aims of the present review were (1) to provide an overview of the already studied and proven impacts as well as of the suggested potential impacts that remain to be tested, (2) to synthesize the current knowledge in the Iberian Peninsula and (3) to suggest future research approaches. Despite some well-documented impacts, an increasing number of non-native fish species and a wide range of diverse ecological situations uncover knowledge gaps which hamper conservation and management efforts. Since the introduction of species is often pointed out as a major cause of extinctions, I encourage research groups and funding agencies to devote more resources to the study of interactions between nonnative and native fishes in order to develop evidence-based species-specific impact assessments.

Specimens belonging to North American representatives of the genus Planorbella Haldeman, 1842 of the gastropod family Planorbidae were found for the first time living at the inlet of a warm stream running from the Ust-Ilimsk Pulp and Paper Plant into the Angara River along with the two common indigenous species Galba truncatula (Pulmonata: Lymnaeidae) and Sibirenauta sibirica (Pulmonata: Physidae). Morphological studies of the shell, the radula and the genitals showed that the newly found Planorbella specimens can most likely be attributed to P. duryi duryi (Wetherby, 1879) while it also contains morphological characters of other species in this genus. It is assumed that the occurrence of Planorbella in East Siberian water bodies is a result of unintentional release from aquarium tanks.

The first invasive record of the green alga Caulerpa racemosa (Forsskal) J. Agardh in the Mediterranean Sea was in 1990 in Tripoli (Libya) (J. Agardh) and since that period, this Chlorophyta has been rapidly spreading to all Mediterranean countries. However, very few assessment studies have been carried out along the Algerian coast. In this paper, we present, for the first time new observation data concerning an indicated proliferation of this invasive species in Salamandre and Stidia (Gulf of Arzew, western Algeria); both these sites are very important for sea fishing activities and traffic.

This paper presents new records of Asian clam Corbicula fluminea in the rivers Mero, Sil and Deva. Records from the Rivers Sil and Deva showed the increase of its spread in the Mino river basin. Findings in the Mero basin represented the first Iberian record of this species outside the Mino basin. Furthermore, it was the most north-western record in the Iberian Peninsula.

The aim of this paper is to present new data and review the current distribution of Corbicula spp. in France. Three morphotypes were recorded during the study - "round form", "light R form" and "saddle form". During April 2009, Corbicula spp. were found in several watercourses in France, including three rivers (Canal de la Somme, Oise and Vilaine) where the taxa were not previously reported. In addition, this is the first report of form S in the River Seine and, the first record of the "light R form" in the River Gard. Molluscs of the genus Corbicula are considered to be a well established alien species in large rivers.

This paper aims to set the record straight regarding the first observations of Corbicula fluminea (Muller, 1775) in the Guadiana River Basin. According to the available data, C. fluminea was first observed in 1988 and not in 2006 as suggested by Perez-Bote and Fernandez (2008). The first observations of C. fluminea in the Guadiana estuary were reported in 2000. In 2003, C. fluminea was already well established in the estuary and in many rivers and streams. C. fluminea is likely to expand its current biogeographic distribution in Portugal, since suitable lentic habitats for colonization will be crea ted by the implementation of the “National program of dams with high hydraulic potential”, which should be concluded by 2016.

Non-native suckermouth armored catfishes (Loricariidae) of the genus Pterygoplichthys are now common throughout much of peninsular Florida. In this paper, we present preliminary observations on interactions between a Pterygoplichthys species, tentatively identified as P. disjunctivus (Weber, 1991), and endangered native Florida manatees, Trichechus manatus latirostris (Harlan, 1824), in artesian spring systems in Florida's St. Johns River drainage. The introduced catfish have become abundant in spring habitats, sites used by manatees as winter thermal refuges. In the spring runs, Pterygoplichthys regularly attaches to manatees and grazes the epibiota on their skin. On occasion, dozens of Pterygoplichthys congregate on individual manatees. Manatee responses varied widely; some did not react visibly to attached catfish whereas others appeared agitated and attempted to dislodge the fish. The costs and/or benefits of this interaction to manatees remain unclear.

* Corresponding author Received 10 March 2009; accepted in revised form 18 August 2009; published online 1 September 2009 Abstract This paper presents a short review of published data and the authors' own observations related to the occurrence of the parasitic worm Aspidogaster conchicola (Baer 1827) in the Chinese pond mussel Sinanodonta woodiana (Lea 1834). Infections were found in some fresh-water bodies in Poland (Konin Lakes System) and Ukraine (Danube Basin). The prevalence of infection ranged from 5 to 30%, intensity of infection - 1-2 specimens/mollusk. Free-living species of ciliates, nematodes and chironomides were also discovered during the investigation of S. woodiana in the Konin Lakes System (Poland).

Botryllid tunicates have become increasingly important as model experimental organisms in a variety of biological and ecological fields, including invasion ecology. This paper summarizes existing botryllid culture methods and offers new ones for culturing Botryllus schlosseri (golden star tunicate) and Botrylloides violaceus (violet tunicate) under laboratory conditions. Techniques for maintaining adult colonies, obtaining larvae, and establishing juvenile cultures are presented. Considerations for designing laboratory experiments using botryllid tunicates are discussed. Key words : Botrylloides , Botryllus , culture techniques, golden star tunicate, violet tunicate Introduction Botryllid tunicates have become increasingly important as model experimental organisms in a variety of biological fields such as immunology, physiology, ecology, genetics, developmental biology, evolutionary biology, and aging (e.g., Boyd et al. 1986; Rinkevich and Shapira 1998; Manni et al. 2007 and references therein). Golden star tunicate

The magnitude of the worldwide invasions of Didemnum vexillum Kott, 2002 has taken a number of years to be comprehended. During the past 15 years, it has been identified as different species depending on its location—D. carnulentum on the U.S. west coast, D. lutarium or D. vestum in New England, D. lahillei or D. helgolandicum in France and the Netherlands, D. vexillum in New Zealand, D. pardum or D. moseleyi in Japan. A number of recent publications refer to it as Didemnum sp. or Didemnum sp. A. This paper presents a chronology of the steps in the development of our awareness and understanding of this species based on comparative morphology and genetics, and lists invaded regions and the approximate minimum length of time it has been known in each area. Evidence is presented that D. vexillum may have originated in Japan. The importation of vast quantities of Japanese oysters and spat into many countries prior to the 1960s is discussed but eliminated as a likely vector because there are no reports of a sudden didemnid ascidian appearance prior to the 1970s. Introductions (including to the type locality in New Zealand) are very likely due to shipping (either via hull or sea chest fouling), with subsequent local spreading by fouled recreational craft, barges, etc., drifting and reattachment of dislodged fragments, and movements of fouled aquaculture stock and gear. Based on morphological and genetic comparisons of hundreds of world-wide samples, museum type specimens, and anecdotal information on the presence of this species in various locations over several or many decades, the valid name is concluded to be Didemnum vexillum Kott, 2002 due to the lack of any pre-existing published description. D. vestum Kott, 2004 is synonymized under D. vexillum.

The assessment of risks associated with alien invasive organisms implies a detailed knowledge of their taxonomical composition and distribution within an assessment unit. In this paper we used both literature data and results from our field surveys of more than forty sites, conducted in 2006-2008, to compile a checklist of aquatic alien species (invertebrates and fish) established in the three large river basins of Belarus (Dnieper, Pripyat, Neman). Thirty six alien species have been revealed, most of which are of Ponto-Caspian origin. The discovery of several new species during our surveys indicates that the rate of introductions has substantially increased over the last two decades.

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 size-frequency structure of post-settlement stages were studied in 2005 and 2006. In addition, changes to water quality parameters in the lake postestablishment 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.

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.

In this paper we have compiled all information on Chinese pond mussel Sinanodonta woodiana (Lea, 1834) in the Czech Republic. This species was found in the Czech Republic for the first time in 1996 and altogether 20 records about its occurrence had been obtained till the beginning of 2008. The species was found in rivers, oxbow lakes and ponds. The expansion is the most intensive in Southern and Central Moravia, which is likely due to the fact that it is the warmest part of the country.

The invasive alga Sargassum muticum has recently been reported in the Firth of Lorn, west coast of Scotland. This represents the first sighting of the species north of the Kintyre Peninsula, a land barrier that had been expected to slow the northwards spread of S. muticum. This paper presents a thorough review of literature concerning the dispersal and establishment of this invasive alga and predicts potential dispersal trajectories and likely areas for future establishment in Scotland. From previous dispersal rates, S. muticum is likely to spread throughout the west coast of Scotland in the next few years, predominantly via natural pathways although anthropogenic vectors may also contribute to dispersal. Sheltered and moderately exposed sea lochs and shorelines, on the west coast of Scotland in particular, are likely to provide favourable conditions for the establishment of persistent populations of S. muticum. Conditions on the north and east coasts of Scotland were considered less favourable, both for the dispersal and establishment of S. muticum. The spread of S. muticum is unlikely to cause serious widespread ecological impacts, however, it does have the potential to cause economic damage to the aquaculture industry which is a major employer on the west coast of Scotland. The establishment of dense highly visible canopies would also constitute a degradation of the natural heritage value of Scottish shorelines. It would be prudent to investigate means of preventing persistent populations from establishing in areas of economic importance or with high natural heritage value.

This risk assessment study follows the environmental match of donor and recipient regions of ballast water and the voyage duration as risk quantifiers. The ports considered were Gothenburg (Sweden), Copenhagen (Denmark), Kiel (Germany), Klaipeda (Lithuania), Kemi, Tornio and Raahe as one port region (Finland), and Skoldvik/Kilpilahti (Finland). All selected Baltic ports have at least one donor port in the highest risk category, all extreme and high risk donor ports are located in Europe, but mostly outside the Baltic Sea. The most frequently reported high-risk donor ports are Rotterdam (6 times), Bremerhaven (5), Amsterdam (4) and Antwerp (3), and most high-risk donor ports are the major hub ports in Europe. The paper concludes with ballast water management scenarios for intra-Baltic shipping and for vessels engaged on voyages outside the Baltic.

Among ca. 750 species of Crustacea recorded from Poland, 18 representatives of 5 orders of macro-crustaceans have been identified as alien species that have invaded or have been introduced to Polish waters. Out of 44 freshwater, brackishwater and semiterrestrial species of Amphipoda occurring in Poland (not counting several stygobiotic species), 8 species from three families may be included in this group. They are Corophiidae: Chelicorophium curvispinum (=Corophium curvispinum), Gammaridae: Gammarus roeselii, G. tigrinus, Chaetogammarus ischnus (=Echinogammarus ischnus), Pontogammaridae: Dikerogammarus haemobaphes, D. villosus, Pontogammarus robustoides and Obesogammarus crassus. It is noticeable that most of them (C. curvispinum, C. ischnus, D. haemobaphes, D. villosus, P. robustoides, O. crassus) are of Ponto-Caspian origin, one species was introduced from North America (G. tigrinus), and one from south-eastern Europe (G. roeselii). All the species listed above have spread widely in Poland, in large rivers and artifical reservoirs (Chelicorophium curvispinum, Dikerogammarus villosus, D. haemobaphes, Pontogammarus robustoides, Gammarus tigrinus) or in medium sized rivers (Gammarus roeselii), in brackish coastal waters (Obesogammarus crassus) or both in fresh and brackish waters (Gammarus tigrinus, Pontogammarus robustoides). In most places they successfully outnumber or even completely replace native amphipod species. This paper presents data on biogeography, history, biology and ecology of alien species, as well as the consequences of their invasion in Poland with an extended bibliography and references to other European countries.

The ctenophore Mnemiopsis leidyi is one of the most cited invasive species due to its ecological and economical impact that occurred in the Black and Caspian Seas in previous years. Recent reports on the species presence in the Baltic and North Seas alarmed the scientific community. While the earliest report of M. leidyi in the Baltic was spring 2006, this paper indicates of the presence of M. leidyi in the Oslofjorden as early as autumn 2005, and discusses the possible invasion routes from its native range along the eastern coast of the Americas.

The recent finding of the signal crayfish, Pacifastacus leniusculus (Dana, 1852) in the Brugneto Lake (Trebbia River basin, Liguria, NW Italy) raises new management problems. In this paper, the results of trapping carried out between November 2005 and October 2006, the population structure and the diseases of P. leniusculus inhabiting Brugneto Lake are analysed. The total sex ratio observed was 1:1.03 (males/females) and it did not differ significantly from the theoretical 1:1 value, whereas the sex ratio recorded during winter differed significantly from the theoretical value. The CPUE (Catch Per Unit Effort) calculated was significantly related both to mean seasonal temperature and water-level variations. Regarding diseases only the presence of chitinoclastic bacteria on exoskeleton were found. Branchiobdellidae (Annelida, Clitellata) were not observed either on the exoskeleton or in the branchialchambers, neither were ectocommensals, nor melanisation caused by bacterial infections on gill filaments. Fortunately, melanised spots on the legs usually caused by an infection of Aphanomyces astaci Schikora were not found.

Among numerous recently introduced species in Serbian waters, two new mussel taxa were detected. The aim of this paper is to present the current distribution of two morphotypes of the Asiatic clam - Corbicula fluminea (Muller, 1774) and C. fluminalis (Muller, 1774), in order to discuss pathways of dispersal and reasons for successful adaptation. According to our results, the morphotype C. fluminea is better adapted to local environmental conditions, while C. fluminalis has rarely been found in Serbia. At present, Asiatic clams are widespread within potamon-type rivers that are under the influence of hydro-morphological alterations and exposed to intensive ship traffic. The distribution of Corbicula, as well as some other alien aquatic invertebrate taxa (Branchiura sowerbyi, Anodonta woodiana, Orconectes limosus), indicate that heavily modified waterways are suitable recipient areas for species introduction and adaptation. Corbicula gen. sp. is a characteristic taxa for Pleistocene interglacial deposits in the Pannonian Plain. The comparison between Pleistocene and recent taxa is necessary in order to categorize Corbicula as either introduced or reintroduced taxa.

In the 2002 North American freshwater limpet Ferrissia fragilis (Tryon, 1863) was recorded for the first time in the continental waters of Black Sea Region. This is considered to be a continuation of invasion in the Black Sea Region as this species was previously introduced into Crimean Peninsula reservoirs in the early 20th century. A juvenile form of F. fragilis found in Central Crimea was previously described as the freshwater limpet Ancylus lacustris brevis (Puzanov 1925). According to the rules and recommendations (8B and 8.3) of the International Code of Zoological Nomenclature we point that this information can not be used as nomenclatural act (recommendation of ICZN about providing of first publication with nomenclature act as printing on paper). Since 2002, F. fragilis has been sampled in the freshwaters of the Dniestr Delta. It was observed that this invader could sustain the extreme conditions of an unusually cold winter (2005-2006).

The tropical Atlantic grapsid crab Percnon gibbesi (H. Milne Edwards, 1853) may be regarded as the most invasive decapod currently expanding its distribution in the Mediterranean Sea. The present paper records its presence in Greek waters since 2004. The species seems well established along the coasts of Messiniakos Gulf, Crete and Rhodes Islands as several individuals of various sizes were observed on shallow, rocky bottoms. The proximity of these localities to ports may hint at shipping as potential vector, but larval transport from already established populations across the Ionian Sea cannot be excluded. The wide adaptability, the potential for colonising new habitats and the population dynamics of P. gibbesi merit further investigation.

The Baltic palaemonid fauna comprises four species: Palaemonetes varians, Palaemon adspersus and two newcomers, P. elegans and P. longirostris. The first three species have been reported from Polish waters. This paper presents the history of faunal change associated with P. elegans recent colonization along the Polish Baltic coast, its estuaries, coastal lakes and lagoons. The oldest record of P. elegans comes from the Vistula deltaic system collected in 2000. Presumably moving eastwards from the Atlantic, the species colonized and formed a vivid, reproducing population all along the studied part of the Baltic shores. In many places it has replaced the native P. adspersus and it has became an abundant element of the palaemonid community in the Gulf of Gdansk and in the Vistula delta, still accompanied by the two other species.

This study reports the presence of three alien molluscs from Iskenderun Bay (SE Turkey). Amathina tricarinata (Linnaeus, 1767) and Petricola hemprichi Issel, 1869 have prior records from other regions of Mediterranean, but, Cardites akabana (Sturany, 1899) first recorded in this paper. Since all of them are present in the Red Sea or Suez Canal, they can be considered as Lessepsian immigrants.

The Australian native colonial ascidian Eudistoma elongatum has spread throughout harbours and oyster farms in Northland, New Zealand. This paper summarizes results of a study on the biology, ecology and potential methods of control of this recently introduced species. Colonies were reproductive for nine months of the year and embryos were present in zooids at water temperatures above 14 o C. Low salinity was most likely the cause of variation in reproductive status observed. Larvae were able to swim for up to 6 hours, and remain viable at temperatures as low as 10°C at salinities above 20 psu. Only acetic acid was effective at killing colonies. Control using heat or other chemicals was not feasible for shallow subtidal populations identified in the study. E. elongatum has the potential to spread further within already occupied harbours, and to more southern harbours in New Zealand.

3 pages, 2 figures, On July 2010, the invasive crab Percnon gibbesi was photographed and captured along the coast of Alexandria (Egypt, Eastern Mediterranean Sea). This represents the first observation of this species in Egyptian waters and the easternmost record for the southern rim of the Mediterranean, We acknowledge the Euromediterranean Center for Climatic Changes and the Italian Ministry for the Environment and the Territory (Project: The impacts of biological invasions and climate change on the biodiversity of the Mediterranean Sea). The suggestions of two anonymous referees improved the quality of this paper

* Corresponding author Abstract This paper provides the first report of non endemic Iberian gudgeon Gobio lozanoi in the Tamega River Basin, Northern Iberian Peninsula, and summarizes new and recently-published information on the current distribution of introduced pumpkinseed Lepomis gibbosus and largemouth bass Micropterus salmoides in the Galicia region.

Francesca Gherardi, Associate Professor at the Department of Biology of the University of Florence, was a brilliant Italian zoologist and ethologist, and one of the most well-known and active experts on alien aquatic species. Since her masters degree in Biology (1979) and her PhD in Animal Biology (Ethology) (1987), both obtained at the University of Florence, Francesca studied the behaviour and ecology of aquatic animals. Initially, most of her research concerned social recognition in crustaceans: she was particularly renowned for her studies on hermit crabs and crayfish, her principal model organisms. Then, from the 1990’s onwards she worked in the field of invasion biology, her main interest until her death. Francesca devoted herself with enthusiasm and energy, not only to the problem of the invasive red swamp crayfish Procambarus clarkii, by revealing several aspects of its behavioral ecology, and by developing with her collaborators different methods for its control, but she gradually became an international expert on crayfish and more generally on aquatic alien species. In all aspects of her life, she was constantly driven by a continuous curiosity, thirst for knowledge and a will to face challenges; this was expressed by exploring and frequently opening new research fields. And she transmitted her drive and passion to the many students she supervised. One of the last papers with her contribution is published in this issue of Aquatic Invasions by Vera Goncalves, her Portuguese PhD student working on the interaction between Procambarus clarkii and the zebra mussel Dreissena polymorpha, an issue of recent increasing interest in Francesca’s team. Francesca Gherardi Florence, Italy, 12 November 1955–14 February 2013 (Photograph by Stephanie Peay)

This paper presents the first record of Corbicula fluminea (Muller, 1774) in the Centeans Ponds, Ribeiras do Louro e Gandaras de Budino wetland (northwestern Iberian Peninsula). This exotic invasive bivalve has been found in January 2008 in the Centeans ponds. The way and date of introduction it is still unknown.

This study aimed to strengthen the knowledge of Didymosphenia geminata distribution in Spain, and to determine which environmental variables were related to its regional distribution and temporal changes in growth and production in two Ebro River tributary basins (Iregua and Najerilla¸ La Rioja Region). Living cells of D. geminata were present in 40% of the studied sites of both basins but only four of the sites developed massive growths. The diatom is widely distributed only in mountain areas of both basins (above 690 masl), which have low average annual air temperature (8.27 ± 0.28 oC) and low water Soluble Reactive Phosphorus (SRP) concentration (average value 0.024 ± 0.007 ppm). Massive growths occur in sites with high light intensity, hydrological regulation of river flow and the lowest measured SRP concentrations (below 0.018 ppm SRP). We carried out an intensive spatio-temporal survey in the Lumbreras River (Iregua basin), where the first massive growth was detected in La Rioja Region. The highest cell densities (1.6 × 105 cells cm−2) and biomass values (480 gDWm−2) were recorded in late summer. An increase in solar radiation and slight rise in water temperature were associated with an increase in biomass over time, but always in waters with low SRP concentration, the key factor that enhances massive growth development. The alteration of the natural streamflow in the Lumbreras River by the Pajares Reservoir and the fact that water is discharged from the hypolimnion (which decreases the summer river water temperature) are important factors in understanding why D. geminata shows such an increase in biomass in a Mediterranean river. This paper provides new insights into the importance of different factors controlling D. geminata massive proliferations in the Mediterranean climate zone, where it is assumed that the species should not develop such massive growths, compared to temperate zones where the majority of previous studies have been carried out. We suggest that changing the reservoir management strategy would be a very important contribution to the control of such significant developments.