The effectiveness of disinfectant and steam exposure treatments to prevent the spread of the highly invasive killer shrimp, Dikerogammarus villosus

Abstract

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. Biological invasions of invasive alien species (IAS) are a major driver of biodiversity loss, and detrimentally affect the structuring, functioning, economic and social value of ecosystems worldwide 1,2. In an age of rapid globalisation, the anthropogenic platforms that facilitate the accidental spread of IAS are well documented and the rate of biological invasions has increased in recent years 3. Invasive alien species, synonymously termed invasive non-native species are species present outside of their native range with associated adverse impacts 4. Given the multiple dispersal pathways and array of vectors 5-8 , freshwater ecosystems in particular are considered to be especially vulnerable to the introduction and further spread of IAS 2,9,10. There is a wide range of users' that access and work in the freshwater environment, all of which can present a risk of spreading IAS from one location to another. Management options for effective and efficient control and eradication of established IAS populations are often complex, expensive, resource-intensive, and can be damaging to non-target species 10,11. Therefore, prevention of the introduction and secondary spread of IAS is the first line of defence. Biosecurity is the collectively term

Better off dead: assessment of aquatic disinfectants and thermal shock treatments to prevent the spread of invasive freshwater bivalves

“…Accordingly, biosecurity measures designed to decontaminate vectors are needed (Caffrey et al 2014). Although a variety of biosecurity protocols designed to prevent the introduction and secondary spread of IAS have been developed and tested, such as immersion in hot water (Anderson et al 2015;Shannon et al 2018), aquatic disinfectants (Cuthbert et al 2018;Bradbeer et al 2020), desiccation exposure (Anderson et al 2015;Coughlan et al 2018a), and hot water spray (Comeau et al 2011), the species-specific and contextdependent relative efficacies of many spread-prevention practices are often unclear or unknown (Anderson et al 2015;Coughlan et al 2019a;Bradbeer et al 2020). As a result, there remains an urgent need to confirm the effectiveness of these treatments for additional IAS, to inform application guidelines to better minimise the risk of further IAS spread (Shannon et al 2018;Crane et al 2019;2020b;Coughlan et al 2019a).…”

Touch too much: aquatic disinfectant and steam exposure treatments can inhibit further spread of invasive bloody-red mysid shrimp Hemimysis anomala

“…DuPont) was examined using 1% (10 g L -1 ) disinfectant solutions, and a 0% (0 g L -1 ) control. A concentration of 1% was selected as this is the minimum recommended by the manufacturers for general disinfection through immersion, with 1% solutions also having been shown to successfully cause mortality of D. villosus (Bradbeer et al 2020) and mosquito larvae (Cuthbert et al 2020). All solutions were made using tap water that had been aerated in advance for [ 24 h. All treatment groups were replicated three times (i.e.…”

“…Furthermore, management options for effective population suppression, or eradication of established invader populations, are often complex, expensive and damaging to nontarget species (Piria et al 2017;Coughlan et al 2018). Accordingly, biosecurity protocols designed to prevent the introduction and spread of IAS are now considered to be an essential component of management strategies (Joyce et al 2019;Bradbeer et al 2020). However, despite the implementation of decontamination protocols, the species-specific efficacy of many proposed biosecurity applications is often unclear or unknown (Coughlan et al 2019;De Stasio et al 2019).…”

“…For example, recent studies have only described partial effectiveness of these disinfectants in killing fragmentary propagules of invasive aquatic plants (Cuthbert et al 2018(Cuthbert et al , 2019Crane et al 2020) or invertebrates with a protective shell (Coughlan et al 2019(Coughlan et al , 2020. However, crustaceans such as the killer shrimp, Dikerogammarus villosus Sowinsky, 1894, appear to be highly susceptible to brief disinfectant immersion and mist-spray exposure (Bradbeer et al 2020). Equally, thermal shock treatments, such as rapid applications of steam, have also been proposed as a mechanism to enable improved decontamination of equipment that vector IAS (Joyce et al 2019).…”

“…Equally, thermal shock treatments, such as rapid applications of steam, have also been proposed as a mechanism to enable improved decontamination of equipment that vector IAS (Joyce et al 2019). In particular, applications of steam lasting 10-30 s can effectively kill invasive macrophytes (Crane et al 2019) and invertebrates (Coughlan et al 2019(Coughlan et al , 2020Joyce et al 2019;Bradbeer et al 2020).…”