Environment

Invasive quagga mussel larvae detected for first time in Idaho waterway

Boise State Public Radio News | By Rachel Cohen

Published September 21, 2023 at 4:30 AM PDT

A quagga mussel found on a boat that was about to enter Yellowstone National Park's Yellowstone Lake is seen Thursday, June 17, 2021, in the park. Quagga mussels are nonnative to the U.S. and can devastate ecosystems by overpopulating lakes and streams. So far, they aren't established in Wyoming waters.

The Idaho State Department of Agriculture announced Monday it had detected invasive quagga mussel larvae in the Snake River in Twin Falls.

Lab results from routine monitoring of Idaho's waters confirmed the presence of the free-floating larvae called "veligers."

"These are microscopic samples, but they had fairly robust tissue," said Chanel Tewalt, the director of ISDA, during a press conference Tuesday.

Quagga and the similar zebra mussels are some of the most aggressive invasive species in the U.S. They’re feared for their ability to significantly damage infrastructure by clogging irrigation pipes, drinking water intakes and dams – destruction that, if a mussel infestation takes hold, could cost Idaho $100 million annually.

The tiny mussels are highly competitive, reproducing much faster than native species. Once they’re found in a waterway, they’re extremely difficult to get rid of.

Until now, the Columbia River Basin was the only major river system in the U.S. without the invasive quagga or zebra mussels.

Gov. Brad Little called the discovery a "potential crisis" Tuesday.

"Simply put, we are managing this potential crisis aggressively because we don't want to lose control," he said. "We do have a fighting chance and must give ourselves the best chance to stop this debilitating pest."

Idaho has spent millions of dollars trying to keep the species out of lakes and reservoirs since 2009 by inspecting boats along state borders. In 2022, the ISDA Invasive Species Program inspected more than 100,000 boats and intercepted 36 of them carrying the mussels.

Call Idaho State Department of Agriculture for boat decontamination

ISDA officials said there's a narrow window to mitigate the spread.

That's why Twin Falls County commissioners closed Centennial Waterfront Park, a popular entry point into the Snake River, through at least Saturday.

ISDA is asking the public to stay out of the water in a stretch on either side of the Perrine Bridge while it collects additional surveys to determine the range of the mussels.

Additionally, if your boat, kayak, paddleboard or fishing equipment has been in the Snake River by Centennial Park in the last 30 days, call ISDA at (208) 332-8620 so they can decontaminate your watercraft.

ISDA may set up wash stations locally, but those have not yet been announced.

Find reporter Rachel Cohen on Twitter @racheld_cohen