Recreational boating activities enable aquatic invasive species (AIS) dispersal among disconnected lakes, as invertebrates and plants caught on or contained within watercraft and equipment used in invaded waterbodies can survive overland transport. Resource management agencies worldwide recommend decontaminating watercraft and equipment using high water pressure, rinsing with hot water, or air-drying for up to seven days to inhibit this mode of secondary spread. There is a lack of studies on

more »

... efficacy of these methods under realistic conditions and considering feasibility for recreational boaters. Hence, we conducted experiments addressing this knowledge gap using AIS present in Ontario, namely zebra mussels (Dreissena polymorpha), banded mystery snails (Viviparus georgianus), spiny waterfleas (Bythotrephes cederstroemi), Eurasian watermilfoil (Myriophyllum spicatum), Carolina fanwort (Cabomba caroliniana), and European frogbit (Hydrocharis morsus-ranae). Washing at high pressures of 900-1200 psi removed the most biological material (90%) from surfaces. Brief (<10s) exposure to water at ≥60°C caused nearly 100% mortality among all species tested, except snails. Acclimation to temperatures from 15°C to 30°C before hot water exposure had little effect on the minimum temperature required for no survival. Air-drying durations producing complete mortality were ≥60h for zebra mussels and spiny waterfleas, and ≥6 days among plants, whereas survival remained high among snails after a week of air-drying. Hot water exposure followed by air-drying was more effective than either method separately against all species tested, reducing either the minimum water temperature or air-drying duration necessary. These findings can inform best management strategies against AIS spread.