ISDA rapid response works to limit quagga spread

Quagga mussels were discovered in the Snake River Sept. 18, prompting a rapid response treatment plan that will kill everything in the water for a stretch of 16 miles.

“Worst case scenario was discovering mussels in the Snake River,” said Sydney Kennedy, the public information officer for the Idaho State Department of Agriculture.

Multiple agencies, including the ISDA, are targeting the contamination to both effectively kill the mussels and monitor or repair the impact on the local river.

"The Snake River is Idaho’s lifeblood, and we are doing everything we can to eradicate quagga mussels from our waters,” Gov. Brad Little said in a news release Tuesday. “The state of Idaho’s swift, aggressive action plan is spearheaded by the Idaho State Department of Agriculture and involves many partners at all levels.”

The ISDA is coordinating with the Idaho Department of Fish and Game, Invasive Species Idaho, Idaho State Police and other state agencies to coordinate an attack to stop the spread of quagga mussels.

Quagga mussels are a rapidly reproducing invasive species. They can clog pipes for drinking water, drains, electricity, pumps, filters or other infrastructure. They also can damage boats as they cling to hard surfaces in dark spaces.

“The quagga mussel poses a major threat to Idaho’s water for drinking, energy, agriculture, recreation and more,” said State Rep. Megan Blanksma said in the release.

The mussels also create their own cultures, affect local biomes and damage local ecosystems. They also spread rapidly and aggressively.

The mussels were located at Centennial Waterfront Park, Twin Falls through standard water monitoring.

Once they were located, ISDA closed public access to the Snake River between Niagara Springs and Twin Falls to prevent the spread of the contamination.

“Once the initial sample was discovered we took samples of the surrounding water bodies,” Kennedy said.

The extent of the contamination so far is within a 16-mile span of the river where a copper treatment was released into the water Oct. 3. The copper treatment of no more than one part per million should cover the scope of the infestation and the projected span of the mussels.

“We anticipated a plume and the treatment is relative,” Kennedy said.

The Idaho Department of Environmental Quality determined the dosage of copper to be a safe level for humans. The dose accounts for dispersion of the copper through the water and should still be enough to kill the mussels.

Treatment will stop today, and further testing will determine if other doses are necessary later.

“Vigilance and proactive measures are crucial to mitigate these impacts and protect both our water and way of life here in Idaho,” Blanksma said. “I have first-hand witnessed the scope of the situation on the Snake River and am confident that the treatment plan is comprehensive to this area of the Snake River. The Idaho State Department of Agriculture’s plan to implement a copper-based treatment is absolutely essential to eradicating the quagga mussel population.”

Fish and Game is monitoring the impact on local fish during the treatment. Fish that don’t swim downstream will die, killing old sturgeon and other species.

Fish that have surfaced include largescale sucker, Northern pikeminnow, common carp and yellow perch, Kennedy said. Fish and Game also detected 25 sturgeon, all of them hatchery stalked.

“Unfortunately, we knew that there was going to be significant fish mortality,” Kennedy said. “There are plans in the works of restocking and relocating.”

Fish and Game will work to plant and relocate fish from hatcheries in the area once the treatment is completely effective. Plans to redevelop the local ecosystems are already being written but recovery will take years.

Algae in the area will also be eradicated, but some local swimmers see that as a good thing.

People who visited the impacted stretch of the river on or after Aug. 18 are encouraged to either hot wash their watercraft or to keep it out of the water for at least 30 days.

Luckily the detection was at the tail end of summer, Kennedy said, so limiting river access hasn’t met resistance with locals.

“As far as treating the area, could you imagine treating that area on the Fourth of July weekend?” Kennedy said.

Right now crowds are dropping off and water flow is low, which is helping to prevent further spread.

Residents are encouraged to do their part and stop at water check stations to hot wash their boats, or to allow them to completely dry and stay out of the water.

“We will not be successful without the support of the public, and we appreciate everyone’s cooperation as we all work together to protect Idaho and our water," Little said in the release.

So far the surrounding lakes in Twin Falls have not tested positive for quagga mussels, and the goal is to continue to protect them. No local lakes have had positive tests in the Panhandle either, Kennedy said.

Watercraft check stations have been instrumental in limiting the spread of mussels from contaminated lakes like Lake Powell or Havasu. Officials at the stations detect mussels all the time, but are able to educate boaters when mussels are detected to limit the spread.

“We have positive foul water tests at check stations all the time, which isn’t big deal,” Kennedy said. “We just conduct a hot wash and prevent the spread of contamination.”

What is a problem is when boaters fail to stop at a check station and contaminations go undetected.

“Idaho State Police have long supported our efforts at the watercraft inspection spots,” Kennedy said. “We don't have any legal authority, but if ISP did see a boat go by they could pull them over.”

Troopers will typically guide people back to the check stations to help encourage awareness and education.

If the spread goes beyond the Snake River, enforcement may need to be ramped up, but right now that isn’t a concern yet, Kennedy said.

“Looking at water flows, it looks like it’s stayed in that area,” Kennedy said. “And again, it’s constant monitoring of upstream or downstream and in nearby lakes.”

For information, for interactive maps, or to view the data from monitoring stations across the state, visit agri.idaho.gov/main/.