Southern California environmentalists are struggling to find ways to control invasive New Zealand mud snails.
The snails hitchhike their way into waterways by clinging to boats and boots, animal fur and bird feathers, the Los Angeles Times reported.
While only one-third the size of a housefly, the snail eats large amounts of food that otherwise would have fed other wildlife.
"We've found there's not much we can do to keep them from spreading," said Steve Martarano, spokesman for the state Department of Fish and Game. "There's just no way we can contain it."
The snails were recently discovered in sections of Malibu Creek, Las Virgenes Creek, Lindero Canyon Creek and Medea Creek. The newspaper said their appearance in Malibu Creek has alarmed environmentalists trying to protect the endangered red-legged frog and Southern steelhead trout.
The snails were first spotted in an Idaho river in the 1980s. The creatures have since established themselves in rivers in 10 Western states and three national parks.
Copyright 2006 by United Press International
Explore further: Yellowstone: Bison slaughters done for the season