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

Abstract

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 (B 90 min) within 2% or 4% solutions for two commonly used disinfectants (Vira-sureÒ Aquatic and VirkonÒ Aquatic) to cause mortality of adult Dreissena bivalves. Further, we assessed the effectiveness of thermal treatments: steam spray (C 100°C; B 120 s); hot air (-500°C; B 60 s); and dry ice exposure (-78°C; B 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

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

“…Similarly, steam spray applications lasting C 10 s were also highly effective. These results are consistent with the high levels of efficacy reported for juvenile bivalves immersed in aquatic disinfectants (Barbour et al 2013), as well as for adult bivalve and macrophyte species exposed to steam spray treatments (Coughlan et al 2019(Coughlan et al , 2020Joyce et al 2019;Crane et al 2019). Further, Bradbeer et al (2020 have shown that 1% disinfectant solutions (Virasure Ò /Virkon Ò Aquatic) and direct steam exposure can consistently achieve 100% mortality of D. villosus following C 2 min immersion, 7.5 mL mistspray with 5 min air exposure, and C 10 s steam spray applications.…”

“…Frequently, this trend appears to be based on perceived rather than proven effectiveness of these products as decontamination agents for IAS. 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). 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).…”

Steam and Flame Applications as Novel Methods of Population Control for Invasive Asian Clam (Corbicula fluminea) and Zebra Mussel (Dreissena polymorpha)

“…Whilst previous studies have highlighted that steam-spray treatments can kill invasive bivalves and decontaminate equipment to prevent their further spread (e.g., Coughlan et al 2019aCoughlan et al , 2020Joyce et al 2019), Experiment 1 of the current study has shown that steam-spray treatments, lasting ≥ 60 s, can also rapidly kill C. fluminea residing on the surface of sand substrate. It appears that the application of extreme heat, such as steam spray, causes the haemolymph and extrapallial fluid in the treated bivalve to boil, rupturing internal soft-tissue structures (NEC pers.…”

“…Overall, these studies highlight the potential use of these novel methods for effective, rapid-response control and possible localised eradication of C. fluminea populations. Further, as part of biosecurity-decontamination protocols, several recent studies have highlighted the use of steam spray as an effective, yet straightforward user-and environmentally friendly mechanism for causing mortality of invasive alien species, including bivalves (Crane et al 2019;Joyce et al 2019;Coughlan et al 2020). In particular, Coughlan et al (2019a) documented that 30 s of direct steam exposure can consistently kill small groups of adult Asian clams.…”