Due to extremely low flows and warm water temperatures, Colorado Parks and Wildlife is asking anglers to voluntarily avoid fishing on the Colorado River between Kremmling and Rifle.

Effective Wednesday, July 7, CPW is placing a full-day voluntary fishing closure on the Colorado River beginning at the Highway 9 bridge in Kremmling downstream to the Highway 13 bridge in Rifle. The voluntary closure will remain in effect until further notice, with a possibility of a mandatory emergency closure to all fishing if conditions worsen.

“We know that anglers care deeply about this fishery,” said CPW Aquatic Biologist Lori Martin. “We need their help to conserve this resource.”

Because of the ongoing drought, flows are down in the river. The USGS gauge on the Colorado River at Catamount Bridgetypically measures between 1,500 and 2,000 cubic feet per second (cfs). The gauge has been measuring 600 – 700 cfs, about half what is historically expected there. The USGS gauge on the Colorado River near Dotsero is running at 1,250 cfs, down from an expected 3,000 - 4,000 cfs. 

CPW’s aquatic biologists on the West Slope are concerned about critically high water temperatures and possible low dissolved oxygen. Some fish mortality has already been observed this summer. In addition to these issues, another factor unique to this year has been multiple mudslides and flash flood events resulting from last year’s fires. This has increased the sediment load in some river sections.

“With the high sediment load, the fish can’t find clear water,” said CPW Aquatic Biologist Kendall Bakich “They’ve got to sit through those conditions. And at nighttime, the temp isn’t coming down enough, so there’s no recovery for those fish right now. They’ve just got to hang on.”

These conditions aren’t just limited to the Colorado River. 

“We’re likely looking at moving into a voluntary fishing closure on the Yampa River from the upstream boundary of the Chuck Lewis State Wildlife Area downstream to the west city limits of the town of Steamboat Springs,” said CPW Aquatic Biologist Bill Atkinson. “Water temps surpassed 75 degrees on Tuesday, so if it hits 75 degrees on Wednesday, the closure will be implemented.”  

Biologists are also closely monitoring the Fraser and upper Colorado Rivers in Grand County, another area where temperatures are edging toward dangerous levels for trout.

Anglers should be aware that most of the major rivers on Colorado’s Western Slope are experiencing adverse conditions heading into the hottest days of summer. Follow the Leave No Trace Principle to “Know Before You Go” to the West Slope this summer and check out conditions related to mandatory and voluntary fishing closures: https://cpw.state.co.us/thingstodo/Pages/StatewideFishingConditions.aspx

Tips for anglers
CPW is encouraging trout anglers to consider fishing early in the day and in higher altitude lakes and streams as hot, dry conditions and reduced water levels increase stress to trout populations.

Heat, drought, and low water levels are contributing to elevated water temperatures in much of Colorado, depleting oxygen levels and leaving trout vulnerable. Trout are cold-water fish that function best in 50-60 degree waters. When temperatures exceed 70 degrees, they often stop feeding and become more susceptible to disease. Warm temperature and low water levels can also lead to algae blooms in rivers and reservoirs which cause oxygen levels to drop when algae die and decompose.

Anglers are asked to carefully consider the water and weather conditions when they go fishing for trout. If water seems too warm or fish appear lethargic, it would be best to leave the fish undisturbed. During mid-summer, try to fish early in the morning when the water is coolest.

“Get out early to avoid the higher water temperatures commonly seen in the afternoon and evening,” Martin said. “Anglers are also encouraged to seek out high-elevation trout lakes and streams, where water temperatures are more suitable and fishing doesn’t potentially add additional stress.”

Martin also urged anglers to add a hand-held thermometer to their fishing kits so they can test the waters they intend to fish.

“Anglers should monitor water temperatures and stop fishing when water temperatures start to approach 70 degrees,” she said. “If trout have difficulty recovering after being caught and are acting lethargic, it’s a good decision to call it quits for the day.”

Other suggestions include using heavier tippet and line to quickly reel in and release the fish, always wetting your hands before handling a fish, and to keep the fish submerged while unhooking and releasing it. Avoid taking the fish out of the water even for a quick photo in these conditions.