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Tracking the invasive New Zealand mudsnail
Author: Kathryn Kirkland
Posted: June 15, 2006
Researchers in PSU’s Center for Lakes and Reservoirs have a couple of serving suggestions for the New Zealand mudsnail: frozen, dried, or marinated in a toxic bath of Formula 409—anything to help prevent the spread of this miniature menace from Down Under.

Working with the U.S. Fish and Wildlife Service, PSU researchers distributed “wanted” cards with information about the mudsnail, and have since found the creature in Coos Bay and in the lower Deschutes River near the Oregon fly-fishing hotspot of Maupin—first sightings in both areas.

The New Zealand mudsnail, though averaging only one-eighth inch in length, can quickly propagate to densities of 50,000 per square foot, literally blanketing riverbeds, crowding out existing species, and wreaking havoc on native plant and fish populations. With a “hatchdoor” known as an operculum, the New Zealand mudsnail can seal itself inside a shell—allowing survival out of water or through a predator’s digestive tract. Early detection of the species, which first appeared in the West in the 1980s, is critical to controlling its spread.

The mudsnail is already prevalent in Oregon’s lower Rogue River, New River, and Umpqua River. It has also been found in Garrison Lake, Floras Lake, Devil’s Lake, and the Coffenberry Lake on the Oregon coast, as well as in the Columbia River estuary and the Snake River.

It is not known how the snail arrived in Oregon, but potential pathways include fish hatcheries, boaters, watershed survey crews, and anglers.

“Although new sightings of this invasive species are disappointing, there are many watersheds in the Pacific Northwest where NZMS have not been discovered, and their spread is not inevitable,” says Dave Allen, director of the Fish and Wildlife Service’s Pacific region.

The Center for Lakes and Reservoirs at PSU provides technical assistance, education, and research on management of lakes and reservoirs with an emphasis on management of aquatic invasive species.