Imagine loading up your fishing gear, heading out to your favorite fishing spot, only to find that it has forever changed – its waters drained, its ecosystem disrupted – all because of an invasive species. Unfortunately, this isn’t just a hypothetical scenario in Colorado anymore.
In October 2023, Colorado Parks and Wildlife discovered five adult zebra mussels while removing buoys at Highline Lake. By 2024, the lake had to be drained in an effort to eradicate them. Then on July 16, 2024, CPW confirmed the presence of zebra mussel veligers in the Colorado River and Government Highline Canal.
A growing threat to Colorado’s waters
These new developments have serious implications for fishing and water recreation in Colorado. Invasive aquatic nuisance species (ANS), like zebra mussels, New Zealand mudsnails, rusty crayfish and eurasian watermilfoil can:
- Clog water intake systems and damage infrastructure.
- Disrupt aquatic ecosystems by filtering out essential nutrients and outcompete native species that fish rely on.
- Alter habitat that fish and native species depend upon for shelter and spawning.
- Threaten recreational access by forcing lake and river closures.
Once zebra mussels and other aquatic nuisance species establish themselves in a waterway, they are nearly impossible to remove. That’s why CPW is working with anglers and recreational water users to stop their spread before it’s too late.
How anglers can help
As an angler, you play a crucial role in protecting Colorado’s waters. Here’s how you can help:
- Clean, Drain and Dry your waders and gear after every trip.
- Use CPW’s new gear and watercraft cleaning stations, now available at key locations statewide.
- Report any sightings of suspicious aquatic species to CPW.
Practicing Leave No Trace Principles (like Know Before You Go and researching nearby cleaning stations ahead of your fishing trip) can make all the difference in keeping our waters healthy and open for future fishing adventures.
By taking these small but essential steps, you’re not just protecting your gear – you’re safeguarding Colorado’s rivers, lakes, reservoirs and the future of fishing in our state.For more information about ANS and threats to Colorado waters, visit CPW’s website.
Taking Your Boat?
The Parks Board passed regulations requiring mandatory watercraft inspection and if necessary decontamination of all boats coming in from out of state, leaving known positive waters in Colorado, and those entering a high risk water where inspections and decontaminations are required by the managing agency. The rules have set the standard for watercraft inspection, decontamination, impoundment, sampling, monitoring, identification and reporting. Find a Colorado Boat Inspection Station near you.

Written by Travis Duncan. Travis is a public information officer for Colorado Parks and Wildlife in Denver.







6 Responses
Just back from New
Zealand and they are dealing with the same problems in their rivers and they are pushing the same Thorough Cleaning before changing rivers or lakes. All the guides will provide the boots or they will clean them there selves.
I found the Rivers are gorgeous but they do not stock the rivers and catching fish were much mor challenging there then it is here. Thanks for what we all get to enjoy.