Coupling Gear Decontamination Trials and Angler Surveys to Minimize Spread of Invasive New Zealand Mud Snails Potamopyrgus antipodarum

Abstract

AbstractThe New Zealand mud snail Potamopyrgus antipodarum (NZMS) is a global invader that is readily spread through attachment to recreational fishing gear. Preventing the spread of NZMSs by decontaminating fishing gear such as waders is a key step toward limiting invasive NZMSs and their ecological impacts; however, the effectiveness of decontamination protocols depends on both the efficacy of the protocol and the willingness of anglers to implement it. We tested the efficacy of three decontaminants (Virkon Aquatic, Formula 409, and bleach) at killing NZMSs on waders using two application techniques (spray versus soak) and two exposure durations (10 versus 20 min). We coupled the results of these tests with responses to a self‐administered online survey that gauged the willingness of anglers to implement several decontamination strategies. Mortality of NZMSs differed widely among decontaminants, with the greatest mortality caused by Formula 409 (mean ± SE = 100 ± 0%), regardless of application type or duration. Bleach produced a mean mortality of 68.75 ± 11.97%, and Virkon Aquatic resulted in a mean mortality of 56.25 ± 11.97%. Neither exposure duration nor application method significantly influenced the degree of NZMS mortality, and their interaction was not significant. Anglers who responded to the survey (n = 339) revealed that Formula 409 was the decontaminant they would be most willing to use. Further, spraying was highly preferred over soaking for all decontaminants. Based on our experimental trials and the angler survey, we developed an angler decontamination metric (ADM) that helps to determine the decontamination strategy that optimizes NZMS mortality on fishing gear. Our ADM indicates that spraying gear with Formula 409 is the most effective NZMS decontamination strategy that anglers are willing to use. Our study is the first to combine the efficacy of NZMS decontaminants and angler willingness to adopt a decontamination strategy. By doing so, we hope to encourage the widespread use of NZMS decontamination of fishing gear to limit the spread and impacts of this increasingly relevant invasive species.