Warning: Eagle River fish are in danger | VailDaily.com
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Warning: Eagle River fish are in danger

Cliff Thompson

It’s an initial step taken by the Division of Wildlife in response to the the worst drought in 125 years, which has left river flows at 20 percent or less of normal. The Yampa River in Routt county already has been closed to angling and boating.

The move is seen as a precursor to voluntary and possible emergency closure of the Eagle River if weather continues warm and dry the water temperatures reach the limits of trout survivability. Catch and release angling in warm conditions can result in dead fish, biologists say.

Those temperatures and oxygen are being gauged by the Division of Wildlife at three points on the Eagle River, Minturn, Avon and at the confluence with the Colorado, using recording thermographs.



So far, the conditions are within survivability limits for trout, says Allen Czenkush, aquatic biologist for the Colorado Division of Wildlife. The devices measure two critical elements of fish survivability – temperature and dissolved oxygen content.

Still now hot enough



Those so far are above trigger points set by the state Wildlife Commission, in authorizing discretionary emergency actions by DOW Director Russell George. Those points are:

– River flows of 25 percent of historical averages.

– Temperatures exceeding 74 degrees Fahrenheit or having an average temperature of 72 degrees.



– Fish populations that develop diseases, such as furunculosis, or show signs of deterioration or daily dissolved oxygen levels of 5 parts per million or less, and other factors.

Czenkush says the Eagle River at Gypsum is flowing at 16 percent of its historical mean, but temperatures and oxygen are not yet at critical levels.

If you can fish without wearing waders, he says, it’s probably too warm for the fish.

“The good thing is the dissolved oxygen is above 5 parts per million,” Czenkush said.

Warm water carries less oxygen than does cold water, which can carry as much as 8 or 9 parts per million, or ppm.

“It doesn’t sound like much – but it’s huge,” he said.

Temperatures on the Eagle River over the last week have risen from nighttime lows of 57 degrees to daytime highs of 70 or 72 degrees, but the temperature spike is brief in duration, he says. Oxygen has remained at 7 ppm.

At Minturn, the temperatures have ranged from 55 to 70 degrees, and the dissolved oxygen level has been 7 ppm.

The Eagle River at the confluence with the Colorado has dissolved oxygen levels at 7 ppm, with temperatures fluxuating from 63 to 74 degrees.

“It gets up in temperature but then turns around and cools,” he said.

Czenkush and Area Wildlife Manager Pat Tucker said closures would be enacted on a consensus basis through meetings with local businesses and government. The DOW will be meeting next week with the Eagle County Commissioners to explain the situation, and state officials already have been talking with area guides and outfitters, Tucker said.

Not yet

“We’re not going to close it yet,” a local DOW manager, Pat Tucker, says. “If conditions worsen, then the next step could be voluntary closure.”

Czenkush said he has looked for dead fish at the measuring stations and has seen none.

“Daily high temperatures are still not quite to the magic number (74 degrees) and the dissolved oxygen is still above the 5 ppm trigger point,” says Czenkush. “This, plus the general lack of corpses, suggests that we should prepare for voluntary closures – but not pull the pin yet.”

Fish biologists said that when water temperature reaches 66 degrees, trout become stressed – and catching them stresses them more. And with less oxygen to breathe, they have to work harder to survive. When stressed, trout will also become more susceptible to diseases, such as furunculosis, a fatal blood-borne infection.

Bob Nock of Eagle River Anglers in Eagle measures the water temperature outside his shop on the banks of the river. He says he has measured temperatures during the heat of the day as high as 70 degrees.

He has been telling anglers to fish smaller, cooler streams at higher elevations.

Fishing outfitter John Cochran of Gorsuch Outfitters in Edwards, meanwhile, has stopped fishing the Eagle River altogether.

“We are going to shift efforts to the Colorado River,” he says, referring to the larger river fed by cool water from reservoirs. “We’ll start earlier and perhaps go to half days only and try to use some of the other resources like spring-fed ponds and going to different areas.”

Bill Perry of Flyfishing Outfitters in Avon said his guides, too, will take clients to the Colorado and other places, scheduling trips for the cooler morning hours.

Up to the weather

Pending closures are largely dependent on the weather. Last year, similar low flows and warming waters caused an outbreak of furunculosis that killed fish in the Eagle River. It was contained when monsoon rains arrived and cooled the water a few critical degrees.

“To date fishermen have been very supportive,” Tucker says.

Weather forecasts call for continued warm weather with occasional scattered thunderstorms.

But closing the rivers to fishing won’t solve the problem, Czenkush says. It merely will remove one of the environmental stressors – angling.

Catch and release

The Colorado Division of Wildlife recommends anglers fish higher, cooler streams. If you practice catch-and-release techiques, follow these rules:

– Use barbless hooks and, if possible, remove the hook with forceps without touching the fish.

– Do not remove the fish from the water when removing the hook.

– Do not squeeze the fish.

– Wet your hands if you must handle a fish. Dry hands damage a fish’s protective slime.

– Hold your breath when releasing a fish. When you need to take a breath, so too, does the fish.


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