Grand Junction now stands at the center of Colorado’s fight against one of the most destructive invasive species in North America. After adult zebra mussels were discovered in the Colorado River for the first time in 2025, Colorado Parks and Wildlife has rolled out a bold new awareness campaign called “Oh Shell No” to stop the spread before it cripples western Colorado’s water systems and farms.

The tiny shellfish can cost the state hundreds of millions of dollars in damage. And this time, the threat hits closer to home than ever before.

Invasive Mussels Reach the Colorado River Heartland

Colorado Parks and Wildlife confirmed the worst fears last year when sampling revealed reproducing populations of zebra mussels in the Colorado River near Grand Junction. Smaller irrigation ponds and lakes connected to the river also tested positive.

These are not the first mussels in Colorado. Quagga mussels have plagued eastern reservoirs for years. But zebra mussels had never established themselves this far west in the Colorado River system until now.

Robert Walters, CPW’s Invasive Species Program Manager, told reporters the discovery changes everything.

“We knew it was only a matter of time,” Walters said. “But finding adults reproducing in the main stem of the Colorado River means they’re here to stay unless we act aggressively.”

Why Grand Junction Faces the Biggest Risk

The Grand Junction area sits in a perfect storm of vulnerability.

Miles of irrigation canals pull water directly from the Colorado River to farms, orchards, and vineyards. Those same canals create warm, slow-moving water that zebra mussels love.

Once mussels attach to headgates, pumps, or pipes, they grow in thick clusters that restrict water flow. Farmers could see their deliveries cut by 30 to 50 percent in heavily infested canals.

“That means less water for crops at the exact time they need it most,” Walters explained. “We’re talking real economic damage to the agricultural community that depends on this water.”

The Government Highline Canal, one of the largest in the region, draws directly from the river. Any infestation there would affect thousands of acres of peaches, wine grapes, and vegetable fields that make western Colorado famous.

“Oh Shell No” Campaign Targets Boat Owners and Water Users

The new campaign uses humor to deliver a deadly serious message: Colorado will not let invasive mussels win without a fight.

Bright orange signs reading “Oh Shell No” are going up at boat ramps, marinas, and irrigation diversions across the western slope. Social media videos show mussels literally taking over pipes while a voice declares, “Not in our state.”

CPW is doubling down on boat inspections. Starting this month, more watercraft inspection stations will open, with full operations by May 1.

Every boat that has been in infested waters must now be professionally decontaminated before launching anywhere else in Colorado. That includes boats coming from out of state.

“We have zero tolerance,” said CPW spokesperson Bridget O’Rourke. “One missed boat can start an infestation that costs millions to manage.”

The Million-Dollar Cost of Doing Nothing

Other states provide grim warnings of what happens when zebra mussels win.

Michigan now spends more than $500 million per year fighting mussel damage to water infrastructure. Power plants, city water systems, and factories all suffer regular shutdowns for cleaning.

In Lake Mead, quagga mussels have already cost water districts tens of millions in repairs and lost efficiency.

Colorado officials estimate that widespread zebra mussel infestation could cost the state between $300 million and $1 billion over the next decade in infrastructure damage alone.

That doesn’t include losses to recreation. Highline Lake State Park, once a boating paradise near Grand Junction, closed to boating for years after quagga mussels arrived.

What Residents Can Do Right Now

CPW officials stress that stopping the spread is still possible, but only if everyone helps.

Here are the three steps every boat owner and water user must follow:

• Clean all mud, plants, and animals from boats and equipment
• Drain all water from bilges, live wells, and engines before leaving any lake or river
• Dry everything completely for at least five days (or use hot water washing when available)

Farmers and irrigation districts are being asked to monitor their canals closely and report any suspicious shell growth immediately.

The message from Colorado Parks and Wildlife is clear: this fight belongs to all of us.

These pristine western Colorado waters feed our farms, power our communities, and draw millions of visitors every year. The discovery of zebra mussels in the Colorado River marks a turning point. But with quick action and public cooperation, Colorado can still keep most of its waters mussel-free.

Because when it comes to invasive mussels taking over our rivers and ruining our way of life, there’s only one acceptable answer.

Oh shell no.