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Quagga mussels found in Idaho, growing concern for B.C. waterways

Boats coming into B.C. from Idaho are considered high risk and must be inspected by COS inspectors

Concerns are growing in the Kootenays and Columbia Basin following the recent appearance of an onerous invasive species in a tributary of the Columbia River.

Idaho State Department of Agriculture (ISDA) confirmed the presence of quagga mussels in the Snake River on Sept. 18, 2023.

“Multiple samples of quagga mussel at larval life stages have been found in the Twin Falls area by ISDA’s early detection monitoring program,” noted the ISDA in a release.

The ISDA implemented a comprehensive and rapid response to the threat. They closed a 16 mile stretch of the Snake River between Twin Falls Dam and Niagara Falls Dam, and from Oct. 3 to Oct. 13, introduced a copper-based treatment called Natrix to eradicate quagga mussels in the mid-Snake River area.

Natrix is approved by EPA for this type of aquatic application, however, it is also deadly to native plants and fish species.

In the 16-mile stretch, Idaho Department of Fish and Game reported on Nov. 7 that the treatment killed thousands of fish (6-7 tons) and a minimum of 48 sturgeon at a cost of about $3M.

ISDA won’t know if their actions were successful until the water warms in the spring and more testing can be done.

Trail anglers coming from a fishing derby in northern Idaho said that upon entering B.C. at the Nelway border last month, they were detained by Canadian Border Services officers.

The officers decommissioned their boats by locking the bow to the trailer, pending a mandatory inspection from BC Conservation Officers Services (COS) Aquatic Invasive Species Inspector.

The anglers were informed of the quagga mussel infestation of Columbia Basin waters when they registered their boats before entering the state, but were unaware of the B.C. government response.

Three days later, an invasive species inspector from Creston showed and released the boat to the owner.

BC Ministry of Water, Land and Resource Stewardship (MWLR) communications officer, Peter Lee, confirmed that immediately following the announcement of the positive detection of quagga mussels in Idaho, the BC Invasive Mussel Defence Program triggered changes that identified all boats coming into B.C. from Idaho as “High Risk.”

“There have been no additional positive detections in other parts of the Columbia River Basin through B.C. or neighbouring jurisdictions’ monitoring programs,” Lee told the Trail Times.

The Snake River runs from the Rockies in Wyoming through Idaho, and drains into the Columbia River in Eastern Washington.

It is the first tributary of the Columbia River and the first waterbody in Idaho to be infested by the invasive mussel.

Staff at the MWLR and Ministry of Environment and Climate Change are consulting with the Canadian Border Services Agency (CBSA) about the heightened importance of coverage at key U.S.-Canada border crossings and will take additional precautionary measures to continue to keep the invasive species out of B.C. waters.

“As a priority, COS Aquatic Invasive Species staff are following up with each notification from CBSA and conducting the necessary inspections and decontaminations when required,” said Lee.

Erin Bates, executive director of CKISS (Central Kootenay Invasive Species Society), says the Snake River infestation is a serious new incursion into the Pacific Northwest Region.

“We are hopeful that invasive mussel spread into B.C. can be prevented, because we know that this issue is being taken very seriously by government, industry and many concerned members of the public,” Bates explained.

“Given this new infestation so close to our region, we would like to see increased restrictions on boat transportation into B.C. from high risk areas such as Idaho, and a ‘pull the plug’ law requiring all watercraft owners to remove drain plugs prior to vessels being transported on public roads.”

CKISS, along with other regional nonprofits, actively promotes the “Clean, Drain, and Dry” message that encourages boaters to prevent the spread of aquatic invasive species.

“With the support of government funding and local industry, CKISS monitors Central Kootenay water bodies for invasive mussels, collecting around 300 samples for laboratory testing each year,” Bates added. “This monitoring will enable a rapid response by government in the event that invasive mussels are identified.”

The Idaho Wildlife Federation (IWF) also expressed its alarm at the finding of Quagga mussels in the Snake.

“Quagga mussels can destroy entire aquatic ecosystems. If we don’t get this right – including adhering to recreational closures – the mussels will spread and destroy nearby, world-renowned fisheries like Silver Creek, the South Fork Snake and the lakes of the Sawtooths and the entire Salmon River.

“Idaho’s fisheries are economic and cultural staples. We must do what we can now to contain and eradicate these mussels to protect those incredible assets.”

A May 2023 provincial report, (Potential Economic Impact of Zebra and Quagga Mussels in BC) indicates that the South and Central Interior and Kootenay regions of the province are considered to be at high risk of zebra or quagga mussel (ZQM) invasion based on available calcium and air temperature data.

Newly settled quagga mussels are difficult to detect as they are thumbnail in size and can survive for several weeks in cool moist environments without being immersed in water, making it easier to facilitate its spread by watercraft between water bodies.

Their microscopic free-swimming larvae, veligers, can survive for several weeks in standing water in boats or other equipment.

One mussel can produce 30,000 to 1 million veligers per year, or between 82 and 2,740 veligers per day.

“Once established, ZQM are extremely difficult to eradicate due to their ability to reproduce rapidly and out compete native species for habitat when they reach high densities, emphasizing the importance of early detection and containment.”

Their presence in the Columbia River in southern B.C. could prove devastating to hydro-electric dams, irrigation and sewage systems, industry, marinas, boaters, all aquatic infrastructure, and other species.

The impact of the invasive species costs provinces and states millions of dollars every year.

ZQM were introduced to the Great Lakes region in the 1980s by transcontinental shipping. Since then, ZQM have been found in over 25 American states as well as the provinces of Ontario, Quebec, and Manitoba.

“Members of the public can help by informing themselves of the risks posed by invasive species and following simple prevention measures such as ‘Clean Drain Dry’ to limit further spread,” advises Bates.

Check out for more information on ZQM.

READ: Society monitors West Kootenay waters for invasive mussels

Jim Bailey

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