Invasive species found in Snake River near Twin Falls, Idaho
By TERRY OTTO for The Columbian
Published: November 25, 2023, 6:05am
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A technician surveys the treatment zone of the mid-Snake River to check the success of the recent treatment for quagga mussels. A routine survey conducted in September found evidence of the invasive mussel, triggering a massive response. (Idaho State Department of Agriculture photo)Photo Gallery
On Sept. 18, 2023, the presence of quagga mussels was confirmed within the Snake River near the town of Twin Falls, Idaho, during regular invasive species monitoring by the Idaho State Department of Agriculture (ISDA).
This is the first time that this invasive and dangerous species has been detected within the Columbia River Basin, the last major river system in North America that was free of these species.
If these mussels gain a foothold in the basin, the results would be catastrophic.
Quagga mussels are native to Russia and the Ukraine. They first arrived in the Great Lakes region during the 80’s. They are filter feeders, have no natural predators, and have spread rapidly throughout the continent.
Justin Bush, Aquatic Invasive Species policy coordinator at the Washington Department of Fish and Wildlife, recently spoke about the threat this species poses, and the multi-state effort to keep them out of the basin.
“I can tell you that each state in the Columbia River Basin has a response plan,” said Bush, “and there is also a regional response plan between all the states. Idaho enacted their plan, and they did it pretty well from an outside perspective.”
The regional plan has also been activated so the states can share information about this invader.
Bush mentioned that no quagga mussels have, as of yet, been detected in the state of Washington.
The economic effects alone could be staggering, let alone what it would mean to the Columbia River fisheries.
“We have really good economic information based on what other states have experienced,” Bush said. “We know that quagga mussels would cost over 100 million dollars in impacts annually to our hydroelectric system. That’s not solving the problem, that’s not eradicating it, that is just to keep our hydroelectric system running.”
He adds that other infrastructure, including irrigation, would also be impacted. It would also affect shipping along the river, as well as recreational activities, boat launches, and of course, the fisheries themselves.
Quagga mussels take over water bodies, and become the main biomass within the systems they colonize. They filter out nutrients needed to sustain fish populations, while not removing any toxins. The water becomes literally too clear, bringing catastrophic changes to the plant life.
Their shells are also razor sharp, and they will collect on any solid surface, such as rocks, pilings, and concrete structures. Waders and swimmers would need to stay clear of hard surfaces, or they could risk slicing their feet on the shells.
These changes would certainly add stressors to the already strained salmon and steelhead populations within the Columbia Basin
“You can imagine a fish ladder covered in razor-sharp shells?” Bush added.
The Idaho response has been quick, and so far, it has seen some success.
Nic Zurfluh is the Bureau Chief of Idaho’s Invasive Species section of the Idaho State Department of Agriculture. He reports that, upon detection, the Idaho response plan was quickly put in motion.
Stakeholders along the river were brought together with state biologists and scientists. Treatment options were discussed. Chelated copper emerged as the best option for treatment, and the plan was put in motion.
The contaminated area of the middle Snake River was treated with the copper at one part per million for 96 hours, then the treatment was halted for 40 hours, followed by another round of 96 hours of treatment.
Initial results showed no remaining veligers, or larvae, and a single adult mussel found during initial surveys died from the treatment. However, it is too early to breathe a sigh of relief, and there are consequences from copper treatment.
“Chelated copper is very toxic to fish,” Zurfluh said. “It affects the gill itself, and early on we started to see mortality: carp, suckers, pike minnow, and sturgeon. The sturgeon are all of hatchery origin, and the area will be restocked.”
Anxiety is high among state managers and scientists.
“It will be a long winter and field season next year,” he added, as state teams will keep an eye on the situation.
It could take as long as five years of repeated treatments and surveys before the river can be declared clean.
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The seriousness of the situation should come as a warning to any one engaged in recreational and commercial fisheries within the Columbia. The incident reveals how important it is to keep these dangerous species from making their way into the Columbia River Basin.
“They can only be moved by people,” Zurfluh said.
That means it is up to every boating recreationist out there to take measures to keep the invaders out.
That brings us to the strategy of “Clean, Drain, Dry.” When transporting any kind of water craft, it is the law to follow these steps.
“Drain” refers to lake water that is typically kept in the live wells, and the bilge area. That means simply pulling the plug. The boat must then sit dry for a few days, and be meticulously cleaned.
If boaters did that many threats could be eliminated, including quagga mussels. Boaters can also call the invasive species hotline and schedule an inspection and cleaning appointment.
It is also the law to stop at the state-run check stations, which are set up near state borders and other main arterials that boaters use. Washington may be running at least five of these stations during peak boating season. If a boat is found to be contaminated, a cleaning agent is used to remove any hitch hikers.
Anyone in southwest Washington that enjoys recreating on the Columbia, be they fishermen or recreational boaters, has a responsibility to take all necessary steps to help keep the Columbia River free of dangerous invasive species, such as quagga mussels.
This is especially true for anyone that enjoys fishing for anadromous species such as salmon and steelhead. The threat to these fish is massive.
If the Columbia becomes the next victim of these invasives, the results would truly be devastating to these species, which are so important to the Northwest, and southwest Washington.
