Colorado Parks and Wildlife is investigating an outbreak of sores on rainbow trout in Eagle County waterways, with bacteria and stress the primary suspects.
The rainbow trout have been reported by anglers and guiding companies in recent days, and CPW has engaged with those parties to collect samples of the affected fish, which were sent to the state’s Aquatic Animal Health Lab in Brush.
While the results are not yet in, CPW aquatic biologist Kendall Bakich said she has seen similar lesions on fish in the Eagle River in the past, as well as other nearby water bodies. A case in Steamboat Lake showed a similar pathology in rainbow trout, Bakich said, occurring directly after the spawning season during warmer water temperatures.
“But it was really this stress-related disease that is caused by bacteria in the water,” Bakich said. “That’s what we suspect we are going to come back with, we’re not exactly sure what bacteria, that’s what the fish lab will figure out.”
