How effective and protective are AIS Removal Methods?

Abstract

Cleaning boats after recreating in lakes is important because boats can transfer aquatic invasive species (AIS) between waterbodies. Fully drying boats is the recommended method to prevent AIS spread, but is not always possible before it's launched into a different waterbody. Self-service tools may be provided at launches to encourage boat cleaning and AIS removal. The tools available vary and may include waterless tools (e.g., vacuum, cloth wipe, compressed air) as well as low-pressure water for rinses. Most studies have focused on boat exteriors and trailers, not boat interiors. We tested the effectiveness of 4 cleaning methods on the interior of a boat fouled to simulate a) typical angling boat and livewell use, and b) waterfowler use including duck decoys and waders. For each simulation, we repeatedly fouled the same boat with an exact count of dead and surrogate AIS to test: 1) hand removal; 2) waterless tools; 3) low-pressure water rinse; and 4) a combination of all methods. We conducted 10 replicates for each cleaning test for each simulation. The effectiveness of the methods depended on the type of AIS (e.g., spiny water fleas versus plant matter), and on the type of boat fouling. All methods in combination or the vacuum alone removed the highest proportion of AIS from both the waterfowler and angling boats. Using additional tools (e.g., wipe, vacuum, or low-pressure rinse) increased the removal of AIS from livewells over hand removal alone. In particular, compressed air removed materials stuck in the livewell drain tubing. Hand removal was the least effective method for cleaning duck decoys and waders. These results provide guidance to state agencies, managers, and cleaning station manufacturers on the best cleaning tools to provide at boat launches to more thoroughly clean boat interiors and gear.