Invasive species are on the march in the Colorado River, threatening everything from endangered native fish in Arizona to Colorado's juicy Palisade peaches.
They lurk in hard to find places and can rapidly multiply, with one species of destructive mussel laying as many as 30,000 eggs.
Finding and containing these cryptic species before they settle into a new area is critical. So scientists are deploying a new tool on the frontlines to find and contain the invaders.
Enter the environmental DNA autosampler.
At first glance, it looks like an unglamorous silver storage trunk with a hose coming out of it. It's hard to tell it's actually a $29,595 sophisticated robot.
The machine autonomously takes water samples to find microscopic traces of organic matter, like scales and skin cells, to determine if invasive species have been present in the water.
U.S. Geological Survey fish biologist Kimberley Dibble has recently been using the tech to search for invasive smallmouth bass in the Colorado River near the Glen Canyon Dam. The predators are devouring native species like razorback suckers and humpback chub.
"It's a major step towards real time bio surveillance of river systems that provides managers with continuous monitoring that would be impossible to collect through traditional sampling alone," Dibble said of the eDNA autosampler.
Before the rise of eDNA technology, scientists were more reliant on more labor-intensive methods like electrofishing to try and find the bass by putting an electric current through the water.
"Efforts to get rid of an invasive species are very costly. It takes a lot of boots on the ground, lots of hands in the water to try to find fish that are relatively rare in a system that haven't started increasing in population size yet," Dibble said.
Scientists say the eDNA autosampler has become a sort of smoke alarm for invasive species. If they're detected, they can alert wildlife managers.
"They can sort of target their rapid response efforts around a specific area to help save time and money," Dibble said.
eDNA detection was born in Europe and began finding elusive bullfrogs in the early 2000s. It was then deployed in the Great Lakes to locate invasive carp.
Adam Sepulveda is a research zoologist and one of Dibble's colleagues at the USGS. He's hoping to build a vast network of autonomous robots to scan western waterways. But the current $29,595 price tag for the commercially available units is an obstacle. Efforts are underway to test the device and eventually scale up the technology.
"We don't really have a kind of continuous spatial network of samplers out. It's a little bit of piecemeal, but we're building up to a point, hopefully, where we do have 10s of samplers out in the environment," he said. "Right now, we probably at any given time, have about three to five out, so we're still at the initial stages of the actual network part."
Trial runs are happening in some of the nation's most remote and sensitive ecosystems. Sepulveda said park rangers at Dinosaur National Monument in northwest Colorado recently set up one of the autosamplers to search for signs of the invasive rusty crayfish in the Green River. He added they were able to let the robot do its sampling work while the humans continued with a list of other duties, like counting birds and bighorn sheep.
"I've been focusing a lot of my efforts on these smaller parks, because the biologists often don't have the time or the personnel to dedicate to highly intensive bio monitoring efforts," he said.
The eDNA autosampler is also joining a critical fight in Colorado's Grand Valley.
The tiny zebra mussel has recently infested more than a hundred miles of the Colorado River, from the Utah border to the confluence of the Eagle River. Farmers worry the mussels could clog irrigation systems and spoil crops like the Palisade Peach. The robot will soon be on the frontlines.
"What we're intending to do with it in 2026 is to deploy it in one of the canal systems over there, in the Grand Junction area just to try to give us the highest probability of detecting something, if and when it starts moving through that canal system," Robert Walters, the leader of Colorado's aquatic nuisance species program, said last week.
The eDNA autosampler will allow the state to increase its sampling frequency in locations it wants to protect from the invaders.
"I think this could be a really, really important smoke alarm, not just for Colorado Parks and Wildlife, but also for the people that are receiving that water," he said.
Walters said the state is also planning to use eDNA sampling in locations upstream of the current zebra mussel infestation. The technology is becoming further integrated into the invasive species rapid response program.
"The technology has been out there. It's just becoming more mainstream and accessible for people to utilize," he said. "We're trying to use all of the tools in the toolbox out there to better understand what's going on in western Colorado."
This story is part of ongoing coverage of the Colorado River, produced by KUNC in Colorado and supported by the Walton Family Foundation. KUNC is solely responsible for its editorial coverage.
Copyright 2026 KUNC
