State defines Mid‑Snake River quarantine area for quagga mussel control; inspections and decontamination required

The Idaho Department of Agriculture presented and the House Agriculture Affairs Committee approved a temporary rule defining the Mid‑Snake River quarantine area for quagga mussel response and control.

Deputy Director Lloyd Knight said the quarantine area, established to support treatment and ongoing surveillance, runs from Hansen Bridge downstream to the Broken Bridge. ‘‘All watercraft launched within that section of river are required to be inspected and decontaminated by our department and our stations prior to launch and when they pull out of the river,’’ Knight said.

Why it matters: Quagga mussels are an invasive freshwater bivalve that can colonize infrastructure, impair water delivery and alter ecosystems. The department emphasized rapid detection and active decontamination stations to limit spread.

Committee exchange and operational details Committee members praised the department's response and asked about the mussel's size and program logistics. Nick Zirflue, Bureau Chief for Invasive Species, said native western bivalves exist in Idaho but do not attach and that the department has a public hotline for photo-based identification. Knight said adult quagga mussels typically reach about the size of a fingernail; the department plans a broader presentation and demonstration for the committee on Feb. 4.

Access considerations The temporary rule was written to allow the public access to the river as soon as treatments and safety checks permitted. Knight told the committee the quarantine language had been adjusted multiple times during active treatment periods to balance control work and public access.

Next steps The department will operate inspection and decontamination stations, update quarantine maps as needed and return to the committee with additional briefings. The committee approved the docket by voice vote with no recorded opposition.