State wildlife officials, partners urge voluntary stop in fishing Roaring Fork River when water temps rise
The Aspen Times
Anglers in the Roaring Fork Valley are being urged to give fish a break on these hot, dry days.
Colorado Parks and Wildlife and multiple partners are urging anglers to carry thermometers with them and quit fishing when the water in rivers and streams hits 67 degrees.
“We’re definitely concerned right now. Temperatures are reaching the high 60s and even 70 on the Colorado (River),” Kendall Bakich, an aquatic biologist with Colorado Parks and Wildlife for area 8, said Tuesday, July 3.
The agency last sought a voluntary fishing closure on the Roaring Fork for high water temperatures and low flows in 2012. Bakich said anglers are urged to go out earlier in the day, when air and water temperatures tend to be lower.
“Two o’clock is a good rule of thumb” of when temperatures climb, she said.
Rick Lofaro, executive director of Basalt-based Roaring Fork Conservancy, said the nonprofit organization is working with Colorado Parks and Wildlife, Trout Unlimited and the Roaring Fork Fishing Guide Alliance to spread the word about the voluntary closures of waters in the valley.
Usually there is not a concern because there is a “robust snowpack,” he noted. The runoff keeps the rivers and streams high and cold. This summer, streams and rivers in the Roaring Fork Watershed are running below 30 percent of average, according to the conservancy’s June 28 river report.
“These extremely low flow conditions are unlikely to improve throughout the summer,” the report said.
The Roaring Fork River near Aspen was flowing at 70.4 cubic feet per second on Friday. The average flow for that date is 361 cfs.
At Glenwood Springs, the Roaring Fork was flowing at 852 cfs compared to an average of 3,730 cfs. Colorado Parks and Wildlife recorded a water temperature of 68 degrees at that location on June 28.
Warm Water means less oxygen
Water in rivers and streams warms up faster when flows are low. Cold water holds more oxygen, Lofaro said. As temperatures climb, the water retains less oxygen.
Bakich said higher temperatures raise the metabolism of trout and other fish.
“They’re using more energy,” she said.
So they might not survive if people continue fishing when the water temperature climbs. She is urging anglers not to play long on the line and don’t remove trout from the water.
The Fryingpan River is less susceptible to warm temperatures because the water released from Ruedi Reservoir is so cold, Bakich said.
The rivers attract anglers from around the world and help fuel the summer economy. All 14 miles of the Fryingpan River between the Ruedi Reservoir dam and the confluence of the Roaring Fork River are considered Gold Medal waters because of the density and size of the trout. In addition, 22 miles of the Roaring Fork River is Gold Medal water.
The Colorado Parks and Wildlife and the conservancy want to reach anglers who are visiting during the busy Fourth of July period and educate them about the voluntary closure.
Lofaro said many fishing guides have been taking clients out earlier in the day to avoid stressing fish further.
Jarrod Hollinger, owner of Aspen Outfitting Co., said guides are the best way to convey the message to stay off the rivers when the temperatures hit 67 degrees. They can educate their clients on the need to watch temperatures and they typically come in contact with anglers who don’t hire guides, he said.
His company focuses on the Roaring Fork River between Aspen and Woody Creek, where it tends to be cooler than stretches further downvalley. Water temperatures in the mornings have remained in the 40s, he said.
His company’s guides are well aware of the need to heed the voluntary closure, if warranted.
“We don’t want to damage the resource,” he said. “We’re probably as protective as anybody out there.”
Bakich said an option for anglers is to go to higher elevations, including high elevation streams and lakes. While lakes can also warm to the danger point for fish, that’s more rare because of the cooler air temperatures and deep water, she said. However, the snowpack was so paltry that many high lakes are already at significantly lower water levels and most of the snowpack has melted.
Bakich said she was part of a group that surveyed conditions at high-elevation lakes in Rocky Mountain National Park recently and found that cutthroat trout weren’t spawning properly. The population observed was “acting funny” by staying outside the channel despite being ripe to deposit eggs, she said. There is concern water temperatures were too high. If so, that could result in lower rates of reproduction, according to Bakich.
Many lakes are deep enough that fish will survive this summer, she said. Her bigger concern is if the 2018-19 winter also brings a lower than average snowpack.
All parties concerned with angling hope that the monsoon materializes and eases the drought this summer. For now, the forecast for the Roaring Fork Valley is dry.
Bakich said if water temperatures start hitting 74 degrees, then it may “pave the way for mandatory closures.” That’s never occurred on the Roaring Fork River. Colorado Parks and Wildlife closed a short, heavily fished section of the Yampa River in northwest Colorado this year because of low streamflows.
“Wildlife officials warn when a fish population is significantly affected by low flows or other unfavorable environmental conditions, it could take several years for it to fully recover if not protected,” the agency said on June 9 when it announced the closure.
Colorado Parks and Wildlife has guidelines for implementing the closure if daily temperatures reach 74 or average 72 degrees; flows drop to 25 percent of historical low flow average, daily dissolved oxygen levels fall below a threshold; and fish exhibit visual signs of disease or mortality.
Reporter Scott Condon can be reached at firstname.lastname@example.org