Click the link to read the article on the Aspen Public Radio website (Michael Fanelli). Here’s an excerpt:
September 9, 2025
About 200 fish were found dead on Aug. 18 on the banks of Grizzly Reservoir, a popular fishing and camping site near Aspen. Colorado Parks and Wildlife officials determined that naturally occurring metals had become toxic for rainbow trout the agency had stocked in the reservoir. Kendall Bakich, an aquatic biologist with CPW, is part of a team measuring the concentration of metals in the reservoir. She said this new metal toxicity is part of a growing trend.
“I would probably say across the world, but certainly across North America, there’s rivers that are becoming more impacted by heavy metals from natural sources, due to climate change,” Bakich said.
Human-caused climate change has led to warming temperatures and drought, increasing the concentration of naturally occurring metals in bodies of water and creating deadly conditions for fish. Bakich said the main culprit in this case was copper, to which fish are especially sensitive. That copper comes from a body of heavy metals at the top of Lincoln Creek, which feeds into Grizzly Reservoir and eventually into the Roaring Fork River.
