Rising water temps stress fish, fishermen in Eagle County
July 25, 2013
EAGLE COUNTY — This summer, the weather’s been hot in the Vail Valley, but did you know it’s so hot that it can be deadly?
Deadly for fish, that is.
Water temperatures in recent days have exceeded the magic number — 70 degrees — where fish have a difficult time surviving and improper fishing can mean death, even for fish you release.
“Trout have a slime-like coating over their bodies, which helps protect them against infectious diseases,” said Brad Dunkle, a guide with Minturn Anglers. “Mishandling, or using improper equipment such as a nylon net, will strip the fish of its slime. The warmer water makes it harder for them to regenerate that slime, so mishandling a fish in warm water can be a death sentence.”
Dunkle and outfits such as Minturn Anglers have been seeking higher ground, where temperatures are cooler.
On Monday, when temps reached 70 degrees in the Eagle River, Dunkle said the water at Piney Lake, where he was guiding, was a cool 55 degrees.
“People will still fish the lower waters in warmer temps, but it really becomes an ethical question,” he said. “What you do in these temps can really affect the future of the fishery.”
Colorado Parks and Wildlife agrees. Kendall Bakich, an aquatic biologist with Colorado Parks and Wildlife said the readings they’ve been taking are worrisome.
“We are particularly concerned about the Colorado River, where water temperatures are exceeding 70 degrees and not cooling down — even overnight,” Bakich said.
Any time water temperatures exceed 74 degrees or reach an average of 72 degrees daily, Colorado Parks and Wildlife may consider imposing emergency fishing closures to reduce unnecessary stress on fish.
Holly Loff, executive director of the Eagle River Watershed Council, said with the rising temps often comes a low waterflow issue, as well.
“The low flows cause further increases in water temperatures,” Loff said. “Low flows also reduce the habitat for the fish, essentially leading to overcrowding in some areas, which further increases the risk of disease.”
Dunkle said the low flows is a separate and troubling issue of its own.
“If you’re talking about low flows on the Colorado River, then you’re also talking about snowmelt that should be coming our way being diverted to the eastern side of the divide,” he said. “That can be a controversial topic.”
Dunkle said pure snowmelt rivers which weren’t being diverted, such as the Eagle River, were also low, but added that the shortening of the days have helped with temps and flows. On Tuesday, the Eagle River near Wolcott reached a high of 68 degrees, and by Wednesday it was back down to a safer 65 degrees. Dunkle also pointed out that Wednesday’s opening of the Green Mountain Reservoir in northern Summit County has helped with flows on the Colorado, adding another 600 cubic feet per second or so.
As things continue to cool off, Loff said fishermen should follow the following precautions:
• Fish before 2 p.m., when the water temperatures are cooler.
• Do not play the fish to exhaustion.
• Keep the fish in the water while releasing it.
• Fish at higher elevations where temperatures are lower.
Follow the water temps at the Eagle River near Wolcott, where the USGS has a thermograph, by visiting http://waterdata.usgs.gov/co/nwis/rt and clicking on the station entitled “Eagle River Below Milk Creek Near Wolcott.”
Staff Writer John LaConte can be reached at 970-748-2988 or email@example.com.