Beds are burning: Eradication and control of invasive asian clam, Corbicula fluminea, with rapid open-flame burn treatments

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.