New Zealand mudsnails are already present in some Wyoming waters but you can stop their spread to other waters by making sure your fishing waders and other gear are Drain, Clean, and Dry.
Origin: New Zealand
Distribution: Throughout the Western U.S. and Great Lakes. They are present in Wyoming in Yellowstone National Park, and in the Bighorn, Shoshone and Snake rivers.
Impacts: They are very prolific and can out-compete native snails and can alter water chemistry at high densities.
Dispersal: In mud on fishing gear, especially waders. They can also disperse downstream through water currents once established in an area.
Characteristics: Light to dark brown, size ~ 0.2 in, elongate shell, 5-6 whorls, operculum visible on live snails.