The Idaho Department of Agriculture says it wants to rid the river of invasive mussels for good, which hasn't been done before in a river system.
There’s only one molluscicide approved by the U.S. Environmental Protection Agency, a copper chemical called Natrix.
Last week, the Idaho Department of Agriculture began spraying the chemical on the shorelines of the Snake River near Twin Falls. It’s part of a round-the-clock effort to get rid of invasive quagga mussels for good.
The state department has created a custom underwater sprinkler system that goes after quagga mussels by coating riverbeds in Natrix.
From a boat in the Snake River, the department’s Lloyd Knight points out hoses running under rock shelves and waterfalls. They’re attached to submerged dispensers spraying Natrix.
“it's a difference between like an automatic sprinkler head where it fans out and irrigating with a hose. If you're watering your lawn, if you have something that distributes that out in a different kind of mist, if you will, you're going to cover a lot more area,” said Knight.
The treatment costs about $3 million and it harms local wildlife.
The first quagga treatment back in 2023 resulted in about 3,500 fish deaths. And a study by the Society of Environmental Toxicology and Chemistry says the lasting effects of copper treatment on riverbeds are still uncertain.
But West Bishop, an algal scientist with Natrix’s creator CePro, said the damage is worth it to prevent a full quagga infestation — not just in the Snake River, but throughout the Columbia River Basin.
“Whether it's the trout, whether it's the salmon industry, uh, downstream, whether it's the organisms in this section here, if the quagga got established, it would have choked them out anyway,” said Bishop.
Research published by the National Academy of Sciences shows that when the mollusk infests the bottom of lakes and rivers, it can become up to 90% of that ecosystem.
It also clogs pipelines, causing hundreds of millions of dollars in damage to irrigation, hydropower and municipal water systems.
The Department killed about half of the Quagga mussels detected in the Snake River last fall, but total eradication is the goal.
If even one microscopic pair of male and female mussels remain, they can quickly reproduce and coat the river bottoms again.
