A state boat-decontamination crew Wednesday discovered the first non-native Zebra mussels in Oregon during a voluntary boat inspection at Interstate 5's port of entry near Ashland, authorities said.

More than two dozen of the mussels, which are feared to invade Oregon waterways and costing millions to control, were found on the motor of a 15-foot Boston Whaler boat whose owner stopped for a voluntary inspection at the port of entry about 11 a.m.

The mussels were removed and kept for analysis while the boat was decontaminated with a hot wash before it was released, says Rick Boatner, the aquatic invasive species coordinator for the Oregon Department of Fish and Wildlife.

The boat's owner, from Everett, Wash., said he bought the boat on eBay from a Michigan resident, Boatner says. The boat was most recently in Arizona and it was en route to Washington, Boatner says.

ODFW crews this spring did a similar decontamination of quagga mussels, another invasive hitchhiker, from a boat entering Oregon from Idaho with quagga mussels.

Since arriving in the Great Lakes in the late 1980s, probably in the ballasts of ships, zebra and quagga mussels have infested the Colorado river system, including Lake Mead in Nevada. States around the West are taking steps to limit their spread because of the damage they inflict.

— Mark Freeman