The expansion of invasive non-indigenous species in the Mediterranean is generating an increasing concern about biodiversity protection and human health, with European countries being solicited to apply early warning measures in such circumstances. The recent expansion of the hazardous fish Lagocephalus sceleratus in the Straits of Sicily, the subsequent actions adopted to manage the risk and the feedback received from the public are herein presented, as an example of the interaction between experts and the public in promoting scientific citizenship through an ad hoc action. A rapid increase in media reports related to L. sceleratus had been registered after the launch of the early warning campaign as part of a scientific and health risk communication strategy, and seven new records of this species have emerged shortly after. This study represents a useful contribution to the further bridging of the science-policy gap.

The European Alien Species Information Network (EASIN) aims to facilitate the exploration of alien species information in Europe, and is recognized as the information system supporting European Union Member States in the implementation of the recently published Invasive Alien Species Regulation. In this paper, we present the role and activities of the EASIN Editorial Board (EB), which is responsible for the quality assurance, safeguarding and constant improvement of EASIN. The EB is supported by a web platform that facilitates online discussions about alien species. This platform creates a virtual community by providing a forum-like interface that is moderated by the EB Members but is freely accessible to the scientific community and the general public. It allows all registered users to make comments, raise questions and share experience and expertise on alien species in Europe. Moreover, it provides a means for exchanging opinions and solving disputes in a transparent way. The overall EB activity is commonly agreed upon procedures and standards.

Negative effects of non-native invasive plants have been well documented, but few studies have examined long-term impacts of non-native plant removal on both native and non-native plant community composition. This case study compared consequences of three non-native invasive removal methods (chemical, mechanical, and a combination of the two), applied to all exotic species, on native and non-native abundance, richness (total number of species), and community composition in two forested sites over six growing seasons. Important non-native vegetative components in pre-treatment and control plant communities included the vines English ivy (Hedera helix Linnaeus, 1753), Japanese honeysuckle (Lonicera japonica Thunberg, 1784), oriental bittersweet (Celastrus orbiculatus Thunberg, 1784), and clematis (Clematis terniflora De Candolle, 1817), and the shrub Chinese privet (Ligustrum sinense Lourero, 1790). In all removal treatments, non-native herbs, tree seedlings, and shrubs declined over six years, and native herbs’ and tree seedlings’ cover and richness increased. Time to implement treatments varied widely (844 person hours / ha for combination vs. 44 h / ha for chemical), but treatment effects only differed for native shrub density (highest in control treatment at one site), and native herb, shrub, and tree seedling richness (highest in mechanical and combination treatments at one site). Treatment did not affect cover or richness of non-native herb and tree seedlings, or shrub density and richness. Native species cover and richness increased as exotic species cover declined for all treatments in this study, suggesting that seed supplementation is not always necessary for community recovery. Spot-application of herbicides to foliage or girdled trees did not significantly hinder native plant community recovery, and no native species except poison ivy (Toxicodendron radicans (Linnaeus) Kuntze, 1891), which was intentionally removed, had its abundance or cover reduced by treatments. Even after treatment, clematis and Chinese privet remained important community components, demonstrating the difficulty in controlling these non-native species. Treatment effects were more pronounced at one site, perhaps due to imperfect selection of control plots, legacy land-use effects, or light limitation. This study supports the need for long-term treatment and measurement to accurately determine native plant community responses to non-native invasive removal.

Electronic decision-support tools are now an essential component of government strategies to battle non-native species, with taxon-specific, paper-based risk analysis schemes often being replaced by taxon-generic tools. This study reports on the development of a decision-support tool for aquatic species, the Aquatic Species Invasiveness Screening Kit (AS-ISK), which replaces five taxon-specific toolkits for amphibians, freshwater and marine fish and invertebrates (FISK, MFISK, FI-ISK, MI-ISK, Amph-ISK). Adapted from Pheloung et al.’s Weed Risk Assessment (WRA), the “-ISK” toolkits were also “self-automated workbooks” in Excel® VisualBasic® architecture of the ’WRA. In creating AS-ISK, we incorporated the conceptual approach (questions and guidance) of the generic risk screening module of the European Non-native Species in Aquaculture Risk Analysis Scheme (ENSARS) into a single “turnkey application” that was based on the Excel® VisualBasic® architecture used by the WRA and its “-ISK” derivatives. Applicable to virtually all climatic zones and all aquatic plants and animals regardless of ecosystem (marine, fresh, brackish water), AS-ISK comprises 49 basic questions on the taxon’s biogeographical and historical traits and its biological and ecological interactions. In compliance with the “minimum requirements” for use with the new EU Regulation on invasive alien species of EU concern, AS-ISK includes a preamble of background information on the species as well as questions on its potential socio-economic impacts and those on ecosystem services, and an additional section (six questions) for the assessor to predict how forecasted changes in climate are likely to influence the risks of introduction, establishment, dispersal and impact of a species. Following a concise but detailed description of AS-ISK, an example assessment of the Manila clam Ruditapes philippinarum is provided, with the French northern coastline as the risk assessment area, to demonstrate use of this decision-support tool. AS-ISK is available for free download at: http://www.cefas.co.uk/nns/tools/.

Introduced marine species can have a large impact upon small countries that are reliant on marine tourism. Non-governmental organisations, such as the World Conservation Union (IUCN), are working with technical experts to implement capacity building and awareness programs that transfers introduced marine species knowledge to countries in need of aid. The Republic of Palau is reliant on tourism and as such is pro-actively engaging in this process to ensure that it has the necessary skills to determine and manage its introduced marine species pathways and vectors. The IUCN with the aid of technical experts implemented a four day training workshop that provided both theoretical and practical field experience with introduced marine species port surveys. An outcome of this exercise was the detection of 11 introduced marine species, the training of 10 Palau agencies and two international organisations, and recommendations for future implementation that will aid Palau to address the problem of introduced marine species within their borders.

In eastern Canada, the initial suspected discovery of the non-indigenous colonial ascidian Diplosoma listerianum in Quebec was followed by species identification and increased awareness for its detection in the neighbouring provinces of Nova Scotia and Prince Edward Island. A phylogenetic analysis was conducted based on sequences generated from the 18S ribosomal DNA gene isolated from tissues of two Canadian samples (Quebec and Nova Scotia) and samples from several species belonging to the Diplosoma genus, which confirmed the species identity of the eastern Canadian specimens. Colonies of D. listerianum found in Quebec (2008) and Nova Scotia (2012) are currently the only tissue records of this species in eastern Canada. Water samples of concentrated plankton collected in Quebec (2010 and 2011) and in Prince Edward Island (2011) tested PCR positive for D. listerianum DNA, but colonies were not observed concurrently. As a case study for early detection, this paper documents how D. listerianum was detected in eastern Canada by different groups (government monitoring, academic research) and with different methods (dive surveys, genetic analysis of water samples, collector plates). This case study suggests that the co-operation between groups and the breadth of the methods used contributed to the early detection of this species in three eastern Canadian provinces. In particular, we show that (i) partnerships between government, academia, and industry, (ii) a national capacity for species-specific molecular detection tools, and (iii) the recognition that the effectiveness and limitations of different monitoring methods may be site-specific can have positive early detection and monitoring outcomes.

A literature search was conducted to summarize studies that quantified the efficacy of ballast water exchange. Here, a number of parameters were collated from 68 studies to provide a meta-analysis of the efficacy of exchange. The percent removal of ballast water, organisms, and various physical parameters was investigated to quantify exchange efficacy in terms of volumetric, biological, and water quality measurements, respectively. The two types of exchanges implemented—empty-refill and flow-through—demonstrated 66 to >99% efficiencies of volumetric exchange when this factor was measured using rhodamine dye as a tracer. Of the reports and papers reviewed, zooplankton were the most common biological parameter studied, and nearly all data showed a decrease in concentrations following exchange, although the changes in community structure varied. Additional biological parameters reported were the concentrations of protists, bacteria, and virus-like particles (VLPs). Results of protist studies were highly variable—ranging from a decrease in cell concentrations to an increase following exchange—while bacteria and VLPs concentrations showed no change in most cases. Of course, the diversity and physiological condition of organisms in ballast water can cause differences in responses that may lead to inconsistencies when determining if organisms were removed during exchange. Additionally, organisms present in sediment may also repopulate ballast water following exchange. In contrast to the biological results, some water quality parameters, such as chromophoric dissolved organic matter (CDOM) and trace elements (e.g., barium and manganese), were consistent indicators of exchange. In conclusion, although the volumetric efficacy of exchange showed, in most studies, that the majority of the water was removed from the tanks, biological and most water quality parameters did not show a consistent response to exchange.

The global transfer of live bait creates a potent vector (mechanism) for invasion of marine species, including associated biota (“hitchhikers”) not intended for shipment. Unlike other vectors of non-native species transfer in coastal marine systems (e.g., ship ballast water), vector management strategies to reduce transport of associated biota with live bait are lacking. In this study, we experimentally tested whether simple, inexpensive treatment methods could reduce hitchhiker abundance and richness with live bait shipments, using the Maine live baitworm trade as a model. The Maine bait industry ships locally-harvested polychaete worms and packing algae to coastal regions of the United States, Europe, and Asia, and may unintentionally transfer associated hitchhikers, including known invaders. We exposed packing algae to three osmotic shock treatments (tap water, hypersaline water, and tap + hypersaline water), and measured abundance and richness of all live and dead macroinvertebrate taxa, as well as the condition of baitworms, after shipment to two locations (Maryland and California). Compared to controls, experimental treatments lowered average abundances by up to 99% and up to 93% for richness, and appeared to have no negative effects on bait or algae quality. The simplest treatment, tap water, was statistically as effective as more complicated treatments in reducing associated biota. We suggest that simple osmotic shock treatments on live packing algae prior to shipping could reduce the prevalence of hitchhikers associated with live trade vectors both nationally and internationally with little impact on the respective industries or their stakeholders.

The prevention of the spread of the zebra mussel is of great concern in many places in North America. The cost of constructing wash stations that provide hot water at high pressure precludes their application as an easy decontamination method. Therefore, the ability to use a garden hose to flush veligers remaining in residual water from the livewell of a boat was examined. Although flushing was not found to be completely effective, more than 90% of veligers were removed after 150 s of flushing.

Invasive non-native species are widespread in freshwaters but their capacity to establish in new lakes has seldom been assessed. In this four-year study (2006–2009), we used Side-scan Sonar and underwater video to illustrate how a 200 ha urban, amenity lake at Cardiff Bay (Wales, UK) was invaded extensively by zebra mussels Dreissena polymorpha (Pallas) within 2–3 years of creation in 2001. Veliger surveys and artificial substrates were used to assess conditions affecting juvenile settlement. Within 5–8 years of lake formation, all hard substrates at 0.5–7 m held mussel densities of 250–6600 m^-2 which, coupled with a crude estimate of habitat available, suggested a lake-wide population of at least 9–31 million adults. Veligers reached 8 (± 2 SE) to 14 (± 4) L^-1 during May–September when water temperatures were >14 °C, but densities and juvenile settlement declined at high discharge when lake flushing rates increased: settled densities in a drier year (2007) exceeded those in a wet year (2008) by 120× implying more effective colonisation under low flows and longer residence times. These data illustrate how rapid invasion by non-native species should be appropriately factored into planning and risk assessments for new water bodies, and potential effects on amenity, ecosystem processes and ecosystem services considered. Our data suggest that drought and low flow under future climates could be a particular risk factor affecting Dreissena colonisation.

The discovery of quagga mussels (Dreissena rostriformis bugensis) in Lake Mead in 2007 was the catalyst for the California Department of Fish and Wildlife to train their canines to detect adult quagga mussels by scent. The use of specialized detection dogs has increased the effectiveness of watercraft inspections and helped prevent further infestations by this invasive species. Since these canines are currently being utilized to detect adult and juvenile quagga mussels, we investigated if canines can detect the veliger larvae stage, as the transportation of larva via watercraft remains a potential pathway of introduction. Although the canines were already imprinted for adult quagga mussels, in which an odor is associated with reward, they required further training to reliably detect veliger larvae populations. Over the course of a 3-day study the canines’ detection rates became more sensitive as familiarity with the veliger odor training progressed. For the lowest concentration blind trial (31 veligers per jar), all canines used in the experiment were able to correctly identify samples with veligers larvae after training.