A significant die-off of mountain whitefish near Steamboat Springs has prompted Colorado Parks and Wildlife to issue another voluntary fishing closure with the mountain whitefish being one of only two native sport species in the state and a species that’s been struggling in recent years.

According to a press release on the matter, more than 300 dead mountain whitefish were found in the lower stretch of the Elk River on Sunday, July 19, with additional deceased fish found downstream. Officials pointed to the drought being behind the die-off, with lower water levels meaning warmer water temperatures. Per a report, water temperature during the investigation into the dead fish was at 82 degrees Fahrenheit, following several days where the temperature was likely above 80 degrees. To help put that into perspective, many river fish species in Colorado start to get stressed and face a higher likelihood of death once the water hits 70 degrees or higher.

“While difficult to see, this type of event was expected given the extreme drought conditions this year,” said CPW Northwest Region Senior Aquatic Biologist Ben Felt. “Mountain whitefish are especially vulnerable to high temperatures and low dissolved oxygen levels. Implementing this closure allows CPW to continue protecting this important native species by reducing angler pressure in this area.”

With the mountain whitefish being one of just two native sport fish found in Colorado – the other one is the cutthroat, the voluntary closure is in effect to protect this stressed fish population. On top of drought concerns, the mountain whitefish has struggled to exist in healthy numbers in recent years in the presence of non-native predatory fish. Additionally, a bad drought in 2002 drastically decreased the population of the species.

The new voluntary fishing closure is on the Elk River, extending from the Christina State Wildlife Area downstream to where the Elk River hits the Yampa. Additionally, several voluntary and mandatory fishing closures are on place on the Yampa, including a voluntary closure from the top of Sarvis Creek State Wildlife Area to roughly 1.6 miles downstream through a Bureau of Land Management-controlled river stretch, a voluntary closure from upstream boundary of the Chuck Lewis State Wildlife Area to the western edge of Steamboat Springs city limits, and a mandatory fishing closure from the Stagecoach State Park dam downstream to the lowermost park boundary. A mandatory commercial closure and a voluntary recreational closure has also been issued by the City of Steamboat Springs, with this closure order including angling.

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