Invasive mussels found on boat at state border east of Spokane

SPOKANE - The Washington Department of Fish and Wildlife (WDFW) yesterday found invasive, non-native zebra mussels on a boat stopped for inspection at the Washington-Idaho border on Interstate 90 just east of Spokane.

The WDFW Aquatic Invasive Species (AIS) crew discovered three mussels on a pontoon boat, which was being transported from Michigan to Alaska.

"Fortunately the mussels were dead and the boat had been out of the water since last fall," said Pam Taylor, WDFW's AIS sergeant in charge of the inspection station. "But the boat made it through several other states with these mussels aboard without detection."

Taylor said the boat received a "high risk" inspection from top to bottom to make sure it was clean, drained, and dry before it was released.

Zebra mussels are native to the Caspian Sea, introduced into the Great Lakes in the mid 1980s in ships' ballast water. The fingernail-size mussels have since spread to more than 20 states and two Canadian provinces where they threaten native fish and wildlife by consuming available food and smothering native species. They also clog water intakes at power plants and other facilities, costing taxpayers millions of dollars a year.

Like quagga mussels, a related species, zebra mussels can live out of water for up to a month and are easily transported on boats.

Yesterday, the AIS crew also inspected another vessel that had been on a Minnesota lake had standing water aboard, Taylor said. Her crew didn't find mussels in that boat, they took a water sample for environmental DNA analysis to determine if mussels had been present. They then drained and dried the boat before releasing it.

The two-month-old inspection station near Spokane operates full-time under a cooperative use agreement on Spokane County Parks property. It replaces the inspection effort conducted since 2016 at the Washington State Patrol commercial truck weigh station on Interstate 90.

The new facility is funded by fees on registered resident boats and by state legislation approved in 2017 that authorized collection of new fees from nonresident watercraft owners and commercial watercraft transporters. Funds also come from the U.S. Army Corps of Engineers and grants secured by WDFW with support from the Pacific States Marine Fisheries Commission and the Washington State Invasive Species Council.

Taylor said the number of watercraft inspected at the new station this year is more than double what it was during the same months last year. This May at least 1,000 watercraft were inspected at the new Spokane station.

WDFW operates another AIS inspection station near the Washington-Oregon border at on the Columbia River south of the Tri-Cities, where about 600 watercraft were inspected during the month of May.

Taylor noted that anyone transporting any kind of watercraft - from from large boats to paddleboards - is required by law to stop at the inspection station.

"If it floats, it's a boat," she said, "and could harbor aquatic invasive species that could harm Washington waters."