Montana’s sparkling waters aren’t typically seen as epic battlefields. But right now they are the front lines of a must-win fight against an extremely dangerous threat: invasive zebra and quagga mussels. And you, dear Sustainable Missoulian, are right in the middle of it.

Before we discuss marching orders, let’s back up.

While they’re a relatively new threat in Montana, invasive zebra and quagga mussels have been in North America since the late 1980s, when they hitched a ride over in the ballast water of Eastern European barges.

From there, they’ve spread at an astonishing rate, wreaking biological and economic havoc as far east as New York’s Hudson River, as far south as Louisiana, and as far west as California.

What’s so scary about these pint-sized pests? They’re stealthy, prolific and mind-bogglingly destructive. Their razor-sharp shells blanket everything they encounter – from other aquatic organisms to pipes, docks, boats and rocks. They ruin water bodies and clog irrigation pipes, head gates, and dam infrastructure that require extensive maintenance, repair and replacement costing hundreds of millions of dollars per year.

The economic impact so far to North America’s industrial, agricultural and municipal water supplies, as well as to water-related tourism, fisheries and property values is billions of dollars and climbing.

Their ecological impacts are even more grim. They attach to and relentlessly smother aquatic insects, native mussels, native vegetation and benthic organisms. They filter food and nutrients from water needed by native fish and other invertebrates.

Filtered water, in turn, allows too much light to reach lake bottoms, accelerating aquatic plant growth. This, coupled with mussel excrement, creates a carpet of waste that fosters the growth of hairy, stinky, toxic mats of algae. Mussels have also been associated with outbreaks of botulism, causing the deaths of thousands of birds in the Great Lakes region.

It’s no stretch to say that such impacts on Montana’s world-famous lakes and waterbodies would be economically and ecologically devastating. Further, the Clark Fork watershed forms the eastern headwaters of the mighty Columbia River – the only major river system in the country that zebra and quagga mussels have not yet reached – making us the Columbia’s last line of defense.

For the last 30-plus years, Montanans have been fortunate that the invasion has been outside our borders. But that all changed in October 2016, when evidence of invasive mussels was found in our state for the first time: larvae in Tiber Reservoir and a “suspect sample” in Canyon Ferry Reservoir.

Because mussels spread primarily by humans, Montana officials, tribes and others have responded with education campaigns, new policies, and a marked increase in inspections, inspection stations, and decontamination stations around the state.

Those are appropriate and much-needed measures. But consider the challenge: We’re battling a critter that, full-grown, is the size of a thumbnail. Its larvae are invisible to the naked eye.  A single female mussel can release up to five million eggs per year. Prolific infestations can occur within months. No mechanical or chemical controls currently exist to prevent or eradicate them.

Is infestation inevitable?

No, it’s not.

Thus far, no adult mussels have been found in Montana. That’s important. We’ve had the chance to respond before it was too late, and a growing number of Montanans now know about the problem. This is a winnable war. But it requires an all-hands-on-deck effort.

That’s where you come in (though you might not know it).

Many folks know that aquatic invasive species like mussels can spread via motorized boats. But they don’t realize that they can also attach to canoes, paddleboards, kayaks, rafts, inflatable duckies, drift boats, waders, fishing equipment and more.

A large majority of us recreate on Montana’s waters in at least one, if not more, of these ways. And even if you don’t, a friend, relative or someone you know most likely does. It’s not someone else’s problem: It’s a responsibility shared by every one of us.

So what are the marching orders?

  • Clean, Drain, Dry.   Yep – all three. Every time. Watercraft, trailers, fishing equipment, waders, etc. Get the details here.
  • Stop at all inspection stations. They aren’t just for motorized boats. Get those canoes, kayaks, rafts, drift boats and personal pontoons inspected! There’s a map of inspection/decontamination stations here.
  • Educate friends and family. You don’t need to recreate on Montana’s waters to help stop the spread of invasive mussels. Word of mouth is more effective than any public education campaign.
  • Learn more about invasive mussels: Some good places to start:  Montana FWP’s “Protect Our Waters” website; and MTPR’s podcast series on the threat of invasive mussels in Montana.

Unfortunately, the battle to prevent the spread of invasive mussels is here to stay. But the good news is, it’s not too late to win it. With your help, Montana can hold the line on this major threat to its irreplaceable and iconic waters.

More river sustainability actions:

  • Help keep our rivers clean: Sign up for the Clark Fork Coalition’s TrashLine! Report trash, or join a hot-shot crew to clean up areas as needed.
  • Get your feet wet for the river! Join the Volunteer River Corps and help with restoration projects, classroom- and field-based watershed education programs, advocacy campaigns, and more.
  • Ensure sustainable use of the urban river: Help conduct river recreation surveys in the Missoula areathis summer: Data will be used to develop sustainable management plans, improve access, and protect the river’s ecological function. Contact to learn more.

Pat Ortmeyer is communications director at the Clark Fork Coalition.

Upcoming sustainability events:

July 11: A Closer Look at Western Montana, An evening of geology, natural history, and forest ecology in the large meeting room at Missoula Public Library, 7-8:30 p.m. FREE & family-friendly!

July 24: Clark Fork Coalition River Survey Volunteer Training, contact volunteer coordinator Katie Racette for more info:, or 406-542-0539 x212. 6-8 p.m.

August 2: Climate Smart Monthly Meetup: Water + Climate, Imagine Nation Brewing Community Room. 5-7 p.m.

August 7: Summer River Cleanup, Join Western Cider & Clark Fork Coalition to clean the urban stretch of the Clark Fork River. Volunteers can then relax with a cold cider and yummy food from local food trucks. 5-8 p.m.