Idaho Snake River Mussels Decreased by 77 Percent
State eradication efforts have significantly reduced larval quagga mussel counts in the Snake River.
Updated on Sept. 26, 2026 in Current Conditions
Live Poll
Should states prioritize high spending to combat invasive species in your local waterways?
Idaho has reported a 77% decrease in larval quagga mussels within the Snake River compared to 2025 levels. These invasive species threaten essential infrastructure like irrigation pipes and hydropower systems.
Why it matters
The Snake River serves as a critical pathway for the mussels to potentially reach the Columbia River, where they could cause millions of dollars in annual damage if they spread.
Official monitoring indicates a 77% drop in larval mussels, verified through 3,500 total plankton tow samples. To date, divers have removed seven adult quagga mussels from the river.
The players
Idaho State Department of Agriculture
This government agency is the primary authority overseeing the state's efforts to monitor and eradicate invasive species within Idaho waterways.
The details
Crews are using plankton nets with 64-micron mesh to collect samples and deploying underwater boom sprayers to inject molluscicides at a target concentration of one part per million of copper. Full eradication of the invasive population requires five consecutive years of no detections.
Timeline
In 2023, the state allocated over $2.3 million for eradication efforts.
Divers removed seven adult quagga mussels as of August 14, 2026.
In 2026, the state allocated over $3.5 million for treatment.
Seasonal Patterns
Idaho's current eradication efforts follow a pattern set by the established invasive species management protocols for the Columbia River basin. These measures are designed to prevent the long-term ecological and economic disruptions associated with uncontrolled mussel infestations.
Residents and boaters should remain vigilant as state-led treatment programs continue to use specialized molluscicides in deep river sections. These efforts are essential to protecting local irrigation and hydropower resources from future damage.
The takeaway
The sharp decline in larval counts represents a successful start to a multi-year recovery process for the river's ecosystem. Preventing the permanent establishment of these mussels is critical for maintaining the state's vital water and energy infrastructure.
Further reading
For more information on waterway management, visit the Current Conditions section.
Source note: This article includes information reported by Opb.
Live Poll
Should states prioritize high spending to combat invasive species in your local waterways?
