It hasn't alarmed an industry that depends on blue ribbon fishing for tourism. It takes something bigger for them to notice. New to the United States, the New Zealand Mud Snail originated in New Zealand and is widely spread throughout Australia, Asia and Europe. The snail has a tough shell and is just millimeters big. They're all female and reproduce live young without mating.
Snails can pass unscathed through a the digestive system of birds and fish.
Species are being moved between continents at a rate that's never happened before. He says evolution produces huge numbers of species in remote islands and isolated mountains. These species are unique but not all that tough in many ways. Along comes an interloper like the New Zealand mud snail, which can live almost indefinitely in something as small as a pop bottle, and the native species are no match. The snails appear to be primarily a Yellowstone National Park phenomenon, but they extend into the Madison River above the Hebgen Reservoir, Gustafson said.