Click the link to read the article on The Aspen Times website (Ali Longwell). Here’s an excerpt:
August 25, 2026
After 2025 saw a flurry of zebra mussel detections in the Colorado River system, Colorado Parks and Wildlife’s weekly sampling this summer has led to zero new discoveries of the invasive species. This does not mean, however, that zebra mussels — notorious for their prolific reproduction and destruction of ecosystems and infrastructure — are gone from the basin or that the battle to curb their spread is over. When zebra mussels establish a presence in a body of water, they multiply quickly. A single zebra mussel can produce up to 30,000 veligers — their microscopic, free-floating larvae — in one spawning event and up to one million in a year. As they root and attach to hard surfaces — like docks, rocks and pipes — and their density increases, they can cause significant damage and clogging to water infrastructure…
This summer, Parks and Wildlife has continued weekly sampling in the Colorado River from its headwaters near Granby to the Colorado-Utah state line, according to Robert Walters, Colorado Parks and Wildlife’s invasive species program manager…Walters said the agency has taken over 500 plankton tow samples since May, not only in the Colorado River, but in its major tributaries including the Gunnison, Roaring Fork and Eagle rivers…Despite the lack of discoveries, the Colorado River, from its confluence with the Eagle River to the state border with Utah, remains one of six bodies of water that are considered infested with the highly invasive zebra mussels. A body of water is considered “infested” when adult and veliger zebra mussels have been found in it. In Colorado, for a body to no longer be considered infested, it must have five consecutive years without detections of that species, according to Walters. The five-year clock resets at each detection.