Champaign, Ill. -- Scientists worry that a rapidly reproducing,
tiny invasive snail recently found in Lake Michigan could hurt
the lake's ecosystem. The New Zealand mud snail joins a long and
growing list of nonnative species moving into the Great Lakes,
threatening to disrupt the food chain and change the local
environment. Scientists checking Lake Michigan water samples
earlier this summer found a population of the New Zealand mud
snail, the Illinois Natural History Survey said. They grow to
only a few millimeters -- several dozen could sit on the surface
of a dime -- making them hard to spot. The snails reproduce
asexually and in large numbers, and have no natural predators in
North America, Kevin Cummings, a scientist who works for the
Natural History Survey, said Thursday. That means they could
quickly spread, at high enough densities to out-compete native
invertebrates for food and living space, he and other scientists
say. "It's hard enough to contain a species once it makes its
way into nonnative wate