SUMMIT COUNTY — Colorado's waterways are being invaded. Mollusks and plants from far-flung places like Russia's Black and Caspian seas, and crustaceans from as close as the Ohio River Basin, have hitchhiked to Rocky Mountain lakes, reservoirs, rivers and streams, jeopardizing native aquatic wildlife and public waterworks infrastructure.

Aquatic nuisance species like zebra mussels, quagga mussels, New Zealand mudsnails and rusty crayfish have thus far not been detected in Summit County's waters. But they're practically banging on our door. Populations of the invasive mussels are already established in Pueblo Reservoir and in multiple reservoirs in Grand County. Stopping them from crossing the county border depends on the vigilance of boaters, anglers and others who enjoy the water.

“Summit County doesn't have any known aquatic nuisance species in it,” said Elizabeth Brown, state invasive species coordinator for the Colorado Division of Wildlfie. “The only way it's going to happen is if people pick them up and bring them. Every individual has the power to be part of the solution to protect the county and the state.”

According to Brown, people can get confused or intimidated by the topic of invasive species, but halting their spread is actually quite simple.

“It's very easy for an everyday person who knows nothing about natural resources biology to stop invasive species just by making sure their boat or ATV doesn't have any biological material on it. Whether on land or water, it's the same message: Keep your stuff clean, take nothing with you, and leave nothing behind,” Brown said.

Taking nothing with you includes not picking up plants or animals from one body of water and move them to another. For that matter, don't take water from one place and move it to another — some species are so small at juvenile stages of development that they're invisible to the naked eye. And if you've become tired of tending your household aquarium, never release species into local habitats.

For recreators, the Division of Wildlife has a mantra: Clean, drain and dry. Those three steps will keep mud, water, plants and animals from traveling.

“You don't need strong chemical solutions. Just clean everything off. Leave your waders upside down so the soles face the sun. Take a toothbrush to clean out the tracks of your boots. Take a beach towel and dry your boat off before you put it back in the car. People think it's really complicated, but it's just good equipment maintenance,” Brown said.

Invasive species don't move on their own. Humans are their vector, intentionally or unintentionally. And once invasives move to a new place, they're free from the natural predators that evolved alongside them and kept them in check in their home environments.

Quickly spreading species

Quagga and zebra mussels spread from Eurasia to the Northeast and Great Lakes in contaminated ballast water of boats, on anchors and on anchor lines. They quickly spread to the Mississippi River, its tributaries and inland lakes and have now established a presence in the Western states.

Both mussels are small barnacle-like mollusks with dark and light stripes. They smother aquatic organisms, such as crayfish and native clams and outcompete for food and aquatic habitat. They damage equipment by attaching to boat motors or hard surfaces and clog water treatment facilities.

Once they're in the water, there's no way to control them, so prevention is the best — and only — cure. Each female mussel produces about one million eggs a year. From the time the mussels enter a water body, they can completely cover its bottom and begin creeping up the shoreline within a matter of five years.

The rusty crayfish, native to the American Midwest, is Colorado's newest invasive aquatic species. It was originally spread by anglers who used it as bait. The crustacean has been discovered in the headwaters of Colorado's Yampa River.

“They don't create the high-dollar cost for water supplies like zebra mussels do, but from an ecological standpoint, they're pretty horrendous. They have strong impacts to the food web and native fishes,” Brown said.

The Eurasian watermilfoil, a submerged aquatic plant, also appeared recently in the Centennial State. It forms extensive, thick, dense mats that clog water bodies, disrupting fisheries, fostering mosquitos and impairing drinking water.

The New Zealand mudsnail was first detected in Colorado rivers and streams in 2004. The mudsnail invades new habitat when it becomes attached to fishing gear, boats, trailers, fish or bait, and then it comes off in the next stream or river. Mudsnails consume aquatic vegetation, upsetting the balance of the aquatic environment.

According to Brown, since none of these invasive species have found a way into Dillon Reservoir, the Blue River or other local waterways, Summit County residents and visitors have a good chance of keeping them out and safeguarding native species and public water supplies.

“Summit County is kind of special — there are things in our state that aren't here yet. So when you go play in other counties, make sure your stuff is clean, and protect the water in your county,” Brown said.

SDN reporter Julie Sutor can be reached at (970) 668-4630 or jsutor@summitdaily.com.