Wildlife officials say a small mollusk has invaded some Wyoming rivers and is spreading.
The Jackson Hole News and Guide reports the rapidly reproducing New Zealand mudsnails have been detected this year in the Salt River in western Wyoming.
Chris Wight, aquatic invasive species specialist for the state Game and Fish Department, says the species is not as disruptive as the quagga or zebra mussels, but they are invasive.
One concern for officials is that the snails can gather in dense concentrations and are capable of blanketing rocks that are critical habitat for species like mayflies and caddis flies, food sources for trout.
The mudsnails are already found in much of the Greater Yellowstone Ecosystem, including the Snake River and Polecat Creek.