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Despite the heat and smoke, it remains a busy summer for the Aquatic Invasive Species Bureau in Montana.

As of Friday, Bureau Chief Tom Woolf said 49 boats have been found with aquatic invasive mussels, far surpassing the 35 boats with mussels detected last year which, at the time, was the all-time record.

There have been around 70,000 boats checked so far this year, Woolf said.

"Conditions have been rough out there," Woolf said. "Inspectors have had a rough run of it and it's been busy ... we're similar to everywhere, where finding and keeping good people is a challenge."

Invasive mussels, such as zebra and quagga, are a growing problem in Montana. Non-native species cause a variety of issues. They can block water flow into hydroelectric turbines — six of Montana's 10 largest power plants by generating capacity are hydro, according to the U.S. Energy Information Administration. They can also increase maintenance costs for irrigation and municipal water supplies.

That's in addition to the environmental impact, which can be significant. Mussels take food resources from other creatures in the ecosystem. They also have few predators, meaning their populations can expand quickly.

"They basically mine the bottom out of the food chain, they eat all the small stuff and there's nothing for the bigger stuff," Woolf said. "So you end up with smaller fish and small populations."

Funding changes

In 2020 budget documents, the bureau received $6.3 million in funding coming from state sources.

Prevention passes for anglers represented 42% of the funding, while hydroelectric fees represented 40%. Smaller portions were funded by a lodging tax, nonresident boat prevention pass fees and money from the state's general fund.

The department was formed in 2009 and until the 2017 legislative session, it was funded by one-time-only general fund appropriations. In 2016, invasive mussel larvae were confirmed at the Tiber Reservoir in northern Montana, prompting dedicated funding to the bureau.

SB 363, which was passed during the 2017 session, generated approximately $7 million and came from a split between hydroelectric and angler fees.

In 2019, the funding stream was changed and diversified. HB 411 added tax revenue and nonresident boat fees. SB 352 then replaced a fee proposed in HB 411 for resident boats with money from the general fund.

Legislative adjustments in 2019 also reduced the cost of angler prevention passes for non-residents from $15 to $7.50 and exempted all non-resident youth age 15 and under.

Importantly, SB 363 established the rate for hydroelectric facilities at $795.76 per megawatt to be paid quarterly. Only facilities that produce hydropower greater than 1.5 megawatts have been affected by any state legislation. There are 18 such facilities in the state, a fiscal note attached to the bill said.

Following the 2017 legislation, a hydroelectric plant such as the Madison Dam — which has eight megawatts of capacity — would pay a little over $25,000 per year under that structure.

The next session, in 2019, the rates were amended by HB 411. It set rates of $274.95 per megawatt for facilities that had capacity of 1.5 to less than 25 megawatts, $549.90 for facilities with the capacity of 25 to less than 100 megawatts. Facilities with capacity of 100 megawatts or more would pay $824.85 per megawatt.

In 2021, however, the rates were amended once again. The last legislative session passed SB 384, which established a rate of $397.88 per megawatt of the facility's capacity.

Now, a dam like the Madison will pay around $12,700 per fiscal year toward aquatic invasive species funding.

The U.S. Energy Administration noted there are two dozen utility-scale hydroelectric plants in Montana. In 2014, NorthWestern Energy purchased 11 plants for $900 million from PPL Montana and those have a total capacity of around 633 megawatts, according to the company's website.

One facility, the Kerr Dam, now called the Salish-Kootenai Dam, was transferred to the Confederated Salish and Kootenai Tribes in 2015.

Both NorthWestern Energy and Avista Corporation testified in support of SB 384 during the last legislative session. Tom Ebzery, a Billings attorney representing Avista, said during the state Senate's Fish and Game Committee meeting on March 25 that in 2017, the two companies were paying a combined total of nearly $3 million in fees to support invasive species funding.

"We have supported the AIS program since its inception and continue to do so, but believe another look at the funding of hydroelectric fees needs to be looked at," Ebzery told the senate committee.

A representative from Montana Trout Unlimited noted opposition to the bill, citing concerns with an attached fiscal note. The note states annual revenue from the hydroelectric invasive species fee would drop from $2.8 million to $1.66 million.

Invasive mussels are an expensive problem — a 2019 report by the Montana Invasive Species Council said they could cost $234 million annually in mitigation and lost revenue.

Hope for the future

Despite issues brought on by the pandemic and increased traffic to Montana's natural lands and water, Woolf and the rest of the bureau continue to work on solutions.

Only one Montana body of water or waterway, the Tiber Reservoir, is listed as contaminated by invasive mussels. It is getting closer to being delisted, Woolf said.

There have been no invasive mussel species detected at Tiber over the past five years, he said. Initially, mussel larvae were found, prompting significant mitigation efforts at the reservoir.

A mandatory boat exit check has been enforced over the past five years, along with mussel-sniffing dogs brought in once the water recedes in the fall to check along the shoreline.

A sled that scrapes the bottom of the lake was also used to look for samples. Solid structures are dropped to the bottom of the lake and periodically checked for mussels. Areas around dams and other permanent structures are also checked.

"If you can kill enough of them, they're not close enough together to successfully reproduce (and) that's what we're thinking, is preventing these," Woolf said. "That's how we explain those mussel detections, we have one detection and then we don't see them again.

"We're hopeful we're in that situation entirely — they were established, we detected them and then just weren't able to make it because of that (water) drawdown situation."

Preventing further mussel invasion also comes down to individual actions. Fish, Wildlife & Parks' message to boaters of "clean, drain, dry" is important, Woolf said.

He also urged those purchasing boats from out of state to contact them for an inspection. The bureau and its partners operate 43 boat inspection stations statewide for around nine months of the year.

"It is preventable," Woolf said. "The problem is us moving boats around. And all we have to do is clean our stuff."

Jordan Hansen covers news and local government for the Missoulian. Shout at him on Twitter @jordyhansen or send him an email at

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