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Suppression of established populations of invasive alien species can be a complex and expensive process, which is frequently unsuccessful. The Asian clam, Corbicula fluminea (Müller, 1774), is considered a high impact invader that can adversely alter freshwater ecosystems and decrease their socioeconomic value. To date, C. fluminea continues to spread and persist within freshwater environments worldwide, despite repeated management attempts to prevent dispersal and suppress established populations. As extensive C. fluminea beds can often become exposed during low-water conditions, the direct application of hot or cold thermal shock treatments has been proposed as suitable mechanism for their control. Further, mechanical substrate disturbance may enhance the efficacy of thermal shock treatments by facilitating exposures to multiple layers of buried clams. In the present study, we advanced these methods by assessing combined applications of both hot and cold thermal shock treatments for control of C. fluminea, using steam spray (≥100 °C; 350 kPa), low- or high-intensity open-flame burns (~1000 °C) and dry ice (−78 °C). In a direct comparison of raking combined with hot thermal shock applications, both steam and high-intensity open-flame treatments tended to be most effective, especially following multiple applications. In addition, when hot thermal treatments are followed by a final cold shock (i.e. dry ice), steam treatments tended to be most effective. Further, when dry ice was applied either alone or prior to an application of a hot shock treatment, substantial if not complete C. fluminea mortality was observed. Overall, this study demonstrated that combined applications of hot and cold thermal shock treatments, applied following the disruption of the substrate, can substantially increase C. fluminea mortality compared to separate hot or cold treatments. [ABSTRACT FROM AUTHOR]

Control strategies for established populations of invasive alien species can be costly and complex endeavours, which are frequently unsuccessful. Therefore, rapid-reaction techniques that are capable of maximising efficacy whilst minimising environmental damage are urgently required. The Asian clam (Corbicula fluminea Müller, 1774), and the zebra mussel (Dreissena polymorpha Pallas, 1771), are invaders capable of adversely affecting the functioning and biodiversity of freshwater ecosystems. Despite efforts to implement substantial population-control measures, both species continue to spread and persist within freshwater environments. As bivalve beds often become exposed during low-water conditions, this study examined the efficacy of steam-spray (≥100 °C, 350 kPa) and open-flame burn treatments (~1000 °C) to kill exposed individuals. Direct steam exposure lasting for 5 min caused 100% mortality of C. fluminea buried at a depth of 3 cm. Further, combined rake and thermal shock treatments, whereby the substrate is disturbed between each application of either a steam or open flame, caused 100% mortality of C. fluminea specimens residing within a 4-cm deep substrate patch, following three consecutive treatment applications. However, deeper 8-cm patches and water-saturated substrate reduced maximum bivalve species mortality rates to 77% and 70%, respectively. Finally, 100% of D. polymorpha specimens were killed following exposure to steam and open-flame treatments lasting for 30 s and 5 s, respectively. Overall, our results confirm the efficacy of thermal shock treatments as a potential tool for substantial control of low-water-exposed bivalves. Although promising, our results require validation through upscaling to field application, with consideration of other substrate types, increased substrate depth, greater bivalve densities, non-target and long-term treatment effects. [ABSTRACT FROM AUTHOR]

Invasive species tend to acquire native parasites from their invaded range over time. In these cases, native host-parasite dynamics may be altered as a result of differences in parasite population biology and host competency between invasive and native hosts. Competent invasive hosts are likely to increase transmission to native hosts while incompetent invasive hosts may dilute infection in natives. In this study, we used a freshwater fish system and a survey approach to compare the host competency and population biology of a dominant helminth parasite, Pomphorhynchus tereticollis, between native brown trout (Salmo trutta) hosts and invasive dace (Leuciscus leuciscus) hosts over 2 years at the core and edge of dace's invasive range in Ireland. Our results show that, although dace acquired P. tereticollis, dace had prevalent and high intensity infections of immature extra-intestinal worms while prevalence of adult worms was consistently higher in brown trout. The majority of parasite individuals infecting dace were immature extra-intestinal forms and, in contrast to brown trout, parasites in dace did not attain sexual maturity. In addition, brown trout from the invasion core where dace have been established the longest had a lower abundance of P. tereticollis, indicating that by taking up but not transmitting infective stages of the parasite, invasive dace may dilute P. tereticollis infection in the native host. [ABSTRACT FROM AUTHOR]

Biosecurity protocols designed to prevent further spread of invasive alien species have become a key component of invader management strategies. Yet, the species-specific efficacy of many biosecurity treatments are frequently unclear or unknown. Invasive quagga, Dreissena bugensis, and zebra mussels, D. polymorpha, are a serious threat to freshwater ecosystems worldwide. Here, we examine the effectiveness of immersion (≤ 90 min) within 2% or 4% solutions for two commonly used disinfectants (Virasure® Aquatic and Virkon® Aquatic) to cause mortality of adult Dreissena bivalves. Further, we assessed the effectiveness of thermal treatments: steam spray (≥ 100 °C; ≤ 120 s); hot air (− 500 °C; ≤ 60 s); and dry ice exposure (− 78 °C; ≤ 300 g; 15 min). Complete mortality of D. polymorpha was observed following exposure to both disinfectants for 90 min, at both concentrations. However, high but incomplete mortality (40–90%) was recorded for D. bugensis across disinfectant treatments. For both species, complete mortality was achieved following 30 s of steam. In addition, 10 s of hot air and 15 min exposure to 300 g of dry ice can both completely killed groups of D. polymorpha. Overall, although the disinfectants did not cause complete mortality, it appears that relatively brief exposure to thermal treatments could be used to curtail the further spread of Dreissena species. [ABSTRACT FROM AUTHOR]

Aquatic invasive alien species (IAS) negatively impact freshwater ecosystems worldwide. As suppression and eradication of established invader populations are often complex, costly and resource-intensive, the prevention of further invader spread is considered a key aspect of proactive management measures. Although broadspectrum aquatic disinfectants have been suggested as a suitable decontamination mechanism to enhance invader spread-prevention strategies, inconsistencies concerning their effectiveness are reported within the literature. Here, we examine the use of two aquatic disinfectants, which were developed to kill damaging microbes, to induce substantial degradation of the apical fragmentary propagules of five invasive macrophytes: Crassula helmsii (Kirk) Cockayne; Egeria densa Planchon; Elodea canadensis Michx; Hydrocotyle ranunculoides Linnaeus; Lagarosiphon major (Ridley) Moss. Apical fragments were exposed to 0% (0 g L-1), 2% (20 g L-1) or 4% (40 g L-1) solutions of Virkon® Aquatic and Virasure® Aquatic, for submergence treatments of five, fifteen, thirty or sixty minutes. After 28 days, degradation of treated fragments was significantly greater than that of control groups, particularly for 4% solutions and longer exposure times. Despite this, sustained viability in relation to shoot and/or root regrowth was exhibited by almost all plant species. However, new shoot growth rates were significantly reduced following exposure to all treatments. At matched concentrations, there was no significant difference between the two disinfectants. Overall, it appears that the examined aquatic disinfectants will not curtail the spread of these invasive macrophytes. Yet, longer submergence times, multiple applications and synergistic effects of different biosecurity treatments may enhance preventative measures against further spread and this requires investigation. [ABSTRACT FROM AUTHOR]

Biosecurity protocols designed to prevent the spread of invasive alien species (IAS) are now an essential aspect of IAS management. However, the effectiveness of various biosecurity treatments requires further exploration. Killer shrimp, Dikerogammarus villosus, a notoriously high impact and ecosystem destabilising invader, has rapidly spread across Europe, and is of concern to invade Northern America. In this study, we examine the effectiveness of three commonly used, broad-spectrum disinfectants to cause mortality of D. villosus: Virasure Aquatic, Virkon Aquatic, and Virkon S. Immersion and spray treatments of 1%, 2% and 4% disinfectant solutions were examined for applications of up to 300 secs immersion and for up to ten consecutive sprays. Furthermore, we assessed the effectiveness of steam (≥100 °C) treatments for up to 120 secs. For all disinfectants, immersion in 1% solutions caused 100% mortality at ≥120 secs. At higher concentrations, shorter immersion times caused complete mortality: 60 and 15 secs for 2% and 4% solutions, respectively. Five sprays of 2% and 4% solutions resulted in 100% mortality, for all disinfectants. Direct steam exposure was highly effective, with complete D. villosus mortality occurring at ≥10 secs. Overall, brief exposure to broad-spectrum disinfectants and direct steam could be used to limit D. villosus spread. [ABSTRACT FROM AUTHOR]

Eradication and suppression strategies for established populations of invasive species require innovative but readily available techniques, which maximise efficacy whilst minimising environmental damage. The Asian clam, Corbicula fluminea (Müller, 1774), is a high impact freshwater invader that can dominate macroinvertebrate communities and physically alter benthic habitats. Globally, despite efforts to implement substantial population control measures, C. fluminea continues to invade, spread and persist within freshwater environments. Accordingly, improved eradication, population suppression and rapid reaction techniques are urgently required. As C. fluminea beds can often become exposed during low water conditions, the present study examines the efficacy of an open-flame heat torch, generating ~ 1000 °C, in killing exposed individuals. Direct and indirect applications of the open-flame torch were examined, for C. fluminea residing on top of or within the substrate, respectively. Experiments revealed that ≥ 3 seconds of direct exposure to the flame causes complete mortality of C. fluminea, while only low mortality rates of between 8-11% were achieved for mud-dwelling C. fluminea following 30 seconds of indirect exposure. However, a longer exposure time of 5 minutes can cause complete mortality of buried C. fluminea. Further, combined rake and burn treatments, where the substrate is disturbed between one minute flame applications, can completely kill all C. fluminea specimens residing within beds, following multiple applications. Overall, these results demonstrate that the application of open-flame heat torch treatments can be used for effective, rapid response and substantial population control of C. fluminea populations residing upon naturally and anthropogenically exposed river, lake and canal beds. Although promising, our laboratory results require up-scaling to field application, including examination of other substrate types, increased substrate depth, and greater bed densities of C. fluminea. [ABSTRACT FROM AUTHOR]

Aquatic invasive species (AIS) negatively impact freshwater ecosystems on a global scale. As management options for control and eradication of established AIS populations are often complex, costly and resource-intensive, spread-prevention protocols are considered essential. The Asian clam, Corbicula fluminea (Müller, 1774), is considered a high-impact successful invader that can adversely alter freshwater habitats, community dynamics and ecosystem function. Accordingly, we examine the efficacy of a range of biosecurity techniques, including recommended (aquatic disinfectants, bleach and salt solutions) and more novel (hot water and direct steam) approaches, to induce adult C. fluminea mortality. In separate experiments, C. fluminea were submerged at 12 °C for up to 80 minutes in: 1) 2% and 4% solutions of Virasure® Aquatic and Virkon® Aquatic; 2) warm (30 °C) 2% and 4% solutions of these disinfectants; and 3) 10% and 20% bleach solutions. Furthermore, specimens were exposed to: 4) 30% and 70% salt solutions (NaCl) for up to 72 hrs; 5) hot water (35, 40 and 45 °C) for up to 20 minutes; and 6), direct steam exposure for up to 10 minutes. Adult C. fluminea were found to be largely resistant to aquatic disinfectants, bleach and salt solutions, with ≤ 58% mortality achieved at the maximum exposure times. However, immersion in hot water (≥ 45 °C) and direct steam exposure for five minutes and 30 seconds, respectively, rapidly caused mortality. Accordingly, simple biosecurity protocols that cause thermal shock appear highly effective. We discuss the need for further examination of biosecurity protocols across all life stages of current, emerging and potential AIS, and provide guidance for improving biosecurity practices. [ABSTRACT FROM AUTHOR]

Outreach is an important element of scientific communication and a prescribed element of many projects, but few scientists have training in communications. This paper describes the outreach element of a project on invasive alien species. A communications plan was drawn up to streamline communications efforts, allowing us to take advantage of unanticipated opportunities to engage with the public, while still maintaining the desired focus, using minimal resources. Here, we use two simple metrics--"passive reach" and "interactions"--to measure the extent and the intensity of communications, and we also look at the advantages and limitations provided by different media. Broadcast media and social media have the capacity to reach a wide audience, but have a low percentage of interaction. Workshops and citizen science events tend to reach a much smaller audience, but generate greater levels of engagement. Understanding these dynamics is important in designing an effective communications plan, which uses the minimum number of resources to generate maximum impact. Building the credibility of the researcher or the project means that your research will reach a wider audience, and your message is more likely to have an impact. [ABSTRACT FROM AUTHOR]

Eradication and control measures for invasive aquatic organisms require innovative methods that maximise efficacy whilst minimising environmental damage. Such methods should also ideally utilise readily available materials and have a relatively straightforward field application. The Asian clam, Corbicula fluminea (Müller, 1774) is a high impact freshwater invader that can dominate macroinvertebrate communities and physically alter benthic habitats. Moreover, C. fluminea has shown a high degree of physiological and ecological plasticity, and has displayed a remarkable capacity for human-mediated passive dispersal. Globally, despite repeated efforts to mitigate spread and implement substantial population control measures, C. fluminea continues to invade and spread. Accordingly, effective population eradication and control measures are urgently required. Here, we examine the efficacy of commercially available dry ice (DI) pellets (i.e. solid CO2 pellets at -78 °C) to kill C. fluminea, when applied both directly (water absent) and indirectly (clams submerged). Experiment 1 revealed the ability of 9 mm DI pellets to induce substantial C. fluminea mortality, with a direct application of 300 g DI at 5 min exposure inducing 100% clam mortality. In experiments 2 and 3, DI pellets of 9 mm induced higher clam mortality than 3 mm pellets, DI slices and mixed DI pellet sizes (3 and 9 mm) at simulated clam densities of 1179 and 3930 individuals m-2, especially when clams were submerged. Experiments 4 and 5 showed that DI application was highly effective even with clams that were covered in gravel or mud, due to the freezing of their surrounding substrate. Accordingly, these results demonstrate that DI can potentially be used for effective, rapid response control and eradication of C. fluminea populations. Whilst promising, our laboratory results require scaling up to field application and examination of the effects of water current, substrate, increased water depth, and greater C. fluminea population densities. [ABSTRACT FROM AUTHOR]

Aquatic alien invasive species (AIS) are a substantial and increasing threat to biodiversity and ecosystem function worldwide. In particular, invasive aquatic macrophytes, such as the South African curly waterweed Lagarosiphon major ((Ridley) Moss 1928), induce major environmental change that often culminates in wide-ranging ecological and socio-economic impacts. Currently, there is a lack of effective biosecurity protocols to mitigate against such invader spread. Here, we examine the efficacy of a broad-spectrum aquatic disinfectant, Virasure® Aquatic, to induce mortality of L. major propagule stages. We assessed the efficacy of Virasure® Aquatic at contact times of 1, 2 and 5 minutes, using 1% (10g L-1) and 4% (40g L-1) concentrations. A necrosis scale was applied to visually assess tissue degradation. Necrosis increased with longer chemical contact times, with fragment degradation optimised at 2 minutes at 1% concentration and 1 minute at 4% concentration. Mode of application was also critical to treatment effectiveness, with spray treatments less effective than submersion treatments. We recommend the use of Virasure® Aquatic via submersion for a minimum period of 2 minutes at 1% concentration or higher. While spray applications should be applied when submersion is not feasible, such as with large water craft, increased spray times beyond those assessed here should be examined. However, results presented suggest that Virasure® Aquatic can effectively reduce the secondary spread of invasive L. major, and may thus form an integral part of biosecurity protocols. The use of broad-spectrum disinfectants and other readily available treatments, that were not purposefully developed for aquatic AIS control but nevertheless are emerging as effective in aquatic AIS management, is discussed and encouraged. [ABSTRACT FROM AUTHOR]

Since its first detection on the island of Ireland in April 2010, the invasive Asian clam Corbicula fluminea (Müller, 1774) has been confirmed present at five sites within the Republic of Ireland (RoI). In March 2016, specimens of C. fluminea were first discovered in Northern Ireland (NI) within the River Foyle, which delineates the border between RoI and NI. In a subsequent survey in June 2016 an established population was confirmed to be present within the River Foyle, where densities of clams attained 384 individuals m-2. This highly invasive species can potentially represent a significant threat to freshwater environments. Therefore, increased biosecurity awareness and enforcement of existing legislation is needed to prevent further spread. [ABSTRACT FROM AUTHOR]

The freshwater hydrozoan Craspedacusta sowerbii was observed for the first time in Ireland at five localities in two separate river catchments (Shannon and Erne) during the summer of 2013. All collected medusae from Lough Derg on the Shannon catchment were female. Analysis of water temperature data for the period 2001-2015 found that water temperatures greater than 21°C were only recorded in 2013. The occurrence of medusae in three distinct areas during this unusually warm summer suggests that it may have been present in its polyp form for some years, or even decades. While it is not known when the species arrived in Ireland, the spread of this species may have involved different pathways. With climate warming, further appearances of the medusa-stage may be expected. [ABSTRACT FROM AUTHOR]

Native Eurasian otter ( Lutra lutra) and introduced American mink ( Mustela vison) carcasses collected throughout Ireland were screened for biliary parasites. Secondary intermediate hosts, Cyprinid fish, were also examined for Opistorchiid metacercariae. Twenty-nine mink and 24 otter gall bladders were screened for biliary parasites. A single mink and three otters were found to be infected with the digenetic trematode Pseudamphistomum truncatum. Eighty-nine percent of roach ( Rutilus rutilus) from the River Shannon were infected with P. truncatum metacercariae, confirming the persistence of the parasite. This is the first record of the species in Ireland, and its recent introduction is probably related to the movement and release of Cyprinid fishes by anglers. [ABSTRACT FROM AUTHOR]