A rescue dog trained to locate invasive zebra and quagga mussels proved her worth over the Memorial Day weekend by finding some of the tiny creatures hidden behind part of a boat's sonar system.

The dog, Puddles, was working at a boat check station on the Washington-Idaho border east of Spokane when she keyed on the live mussels on a boat being hauled from Lake Havasu, Ariz.

Owners of the boat had stopped at three other inspection stations in Montana and Idaho, where inspectors found some mussels and decontaminated the boat, Washington Department of Fish and Wildlife spokeswoman Staci Lehman said. But these mussels were hidden behind some equipment mounted with bolts, where inspectors would have had to go beyond their typical thorough check.

"Puddles' nose was able to detect what human eyes had missed," a news release from the Washington Department of Fish and Wildlife said. "Without a canine partner like Puddles, these mussels would not have been found and could have ended up costing millions of dollars in damage in a body of water that doesn't already have invasive mussels."

If that body of water was the Columbia River or a lake or tributary connecting to it, the U.S. Fish and Wildlife Service estimates a mussel invasion could cost hydroelectric facilities up to $300 million a year, and hundreds of millions of dollars more in environmental damage and increased expenses for fish hatcheries and irrigators. The Columbia River is the only major U.S. basin that still has no known zebra or quagga mussels, and four Northwest states are working together to keep it that way.

Agencies in Washington, Oregon, Idaho and Montana all promote a "Clean, Drain and Dry" campaign, reminding boaters to apply those measures every time their boats come out of water. Last summer, the U.S. Army Corps of Engineers released a draft rapid response plan to be ready for a detection of mussels in the Columbia Basin.

In Montana—where mussels were detected in Canyon Ferry and Tiber reservoirs in 2016—the Montana Fish, Wildlife and Parks collaborates with other agencies to operate more than 25 roadside watercraft inspection stations across the state.

The agency also requires inspections of all watercraft traveling west across the Continental Divide into the Columbia River basin; leaving the Tiber reservoir; or launching within the Flathead Basin that were last launched outside the basin.

Nonresidents transporting and launching watercraft in Montana have to purchase a Vessel Aquatic Invasive Species Prevention Pass, and all people with watercraft coming into Montana from another state must seek out an inspection before launching in Montana.

In all four states, all watercraft must stop at all open inspection stations they encounter. The rules apply to all watercraft, including kayaks and other nonmotorized vessels.

Native to the Caspian and Black seas in Eastern Europe, zebra mussels were first identified in the U.S. Great Lakes in 1989, and have since spread to 20 U.S. states and two Canadian provinces. Quagga mussels arrived a year later. Both spread easily by attaching themselves to boats. They can live out of water for as long as 30 days, and populate a new water body once the boat launches in a new location.

To help prevent invasive mussels from spreading, WDFW received a grant from the Bureau of Reclamation to purchase Puddles for its check station program. She was discovered at an animal shelter in Fresno, Calif., by the Green Dog Project's Rescued for a Reason program and trained to detect mussels.

K.C. Mehaffey covers fish issues for Clearing Up, and is editor of the NW Fishletter. She joined the NewsData writing team in February 2018. From lawsuits to scientific studies, she is enjoying the deep dive into the Columbia Basin's many fish topics.