The presence of an invasive species new to eastern United States has been confirmed in Centre County's Spring Creek, a storied limestone waterway that has been fished by fly anglers since the early 1700s.

Samples of the New Zealand mudsnail (Potamopyrgus antipodarium) were collected by the state Department of Environmental Protection from the Benner Spring State Fish Hatchery to the Route 550 bridge near Bellefonte.

The tiny snails measure less than a quarter inch, with a long coiled shell with deep grooves. In a non-native environment with few predators, they multiply rapidly, disrupting ecosystems by competing with native species for space and food.

"The effects of the snail on higher organisms, such as fish, are not certain at this time," said Bob Morgan, a state Fish and Boat Commission ecologist, in a written statement.

"As with many aquatic invasive species, they are nearly impossible to eradicate once established. This is even more difficult with the mudsnail because it usually takes only one small snail to be able to produce offspring."

Spring Creek is one of the most heavily fished trout streams in the state. It's likely the snail was unintentionally imported on an angler's gear. Unlike some invasives, the mudsnail is hard to kill. Washing won't do -- gear must be frozen for at least six hours, soaked for five minutes in 120-140 degree water (which damages Gortex products), or soaked for five minutes in a 50-50 mixture of Formula 409 Cleaner Degreaser Disinfectant and water.

This is the second hit by an invasive species on a classic Pennsylvania trout stream this year. In June, didymo algae was discovered near Williamsport, Lycoming County, in Pine Creek, a Pennsylvania Scenic River flowing through the Pennsylvania Grand Canyon.

First Published: October 20, 2013, 12:00 a.m.
Updated: October 20, 2013, 12:10 a.m.