Oct 16, 2023 - News

Colorado grapples with a rise of invasive species

Five adult zebra mussels were found on the bottom of buoys located throughout Highline Lake on Oct. 1. Photo: Courtesy of R. Gonzales/Colorado Parks and Wildlife

Invasive species are seeping into the Centennial State — and the Colorado River system — as climate change takes its toll on the environment.

Why it matters: Non-native critters threaten to disrupt the equilibrium of Colorado's ecosystem, posing harmful and long-lasting consequences for some of the most pristine parts of the state.

Driving the news: Colorado Parks and Wildlife announced a plan on Thursday to eradicate zebra mussels from Highline Lake State Park, near Grand Junction, by chemically treating the lake and emptying it completely of water by the end of 2024.

  • The move comes after more than a dozen mussels have been found there over the last year, including five on Oct. 1 — and the first time wildlife officials have categorized a body of water in the state as "infested" with the species.
  • One female zebra mussel can produce more than 30,000 eggs in a single reproductive cycle, officials say.

Between the lines: The plan is bad news for the lake's fish population. CPW officials aren't moving the fish before draining the lake for fear of further spreading any mussels that could be latched onto or inside of them.

What else: In another unprecedented finding, last month CPW reported the discovery of rusty crayfish in Lake Granby, one of the main reservoirs that flows into the Colorado River system.

  • It marked the first time the invasive species — known to devour nearly everything and have few predators — had been detected in the Upper Colorado River Basin.
  • Wildlife officials are now on high alert. Traps have been placed in the water, and anglers are encouraged to kill any they find.

What they're saying: "While finding any invasive species is detrimental to our state's aquatic ecosystems, finding rusty crayfish in Lake Granby, which feeds into the Colorado River, poses an even greater threat to the entire Colorado River Basin," Robert Walters, CPW's invasive species program manager, said in a statement.

Photo: Courtesy of Colorado Parks and Wildlife

Of note: Wildlife officials have never been successful in completely removing rusty crayfish from any bodies of water where they've been found, Walters told the Colorado Sun.

The big picture: Invasive species are thriving in rising temperatures and becoming a growing threat to the Colorado River, The Hill reports.

  • From smallmouth bass to green sunfish, numerous unwanted species are springing up in warmer waters and jeopardizing the future of the river's native inhabitants.

What to watch: The Bureau of Reclamation announced this month that it was launching a formal process to review proposals that would shift the flow and temperature of the Colorado River's Glen Canyon Dam in hopes of disturbing invasive species' downstream production.


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