Trout fishing threatened as Colorado River temperatures warmed

The river’s waters are warming to levels that threaten the livelihood of prized fish and the valuable tourism industry.

Arizona, USA – The drought of the southwestern desert is causing ripple effects everywhere, including Colorado River. The river’s waters are warming to levels that threaten the livelihood of prized fish and the valuable tourism industry.

Rainbow trout fishing is a national lottery

Fishing guide Dave Trimble has been taking anglers up the Colorado River for more than two decades.

“It’s our office, our home, and the place where we spend time with the people we care about and love to fish with,” Trimble said.

Trout fishing with flies attracts tourists from all over the country and maintains a small collection of fishing guides such as Trimble.

But conditions change on the river and threaten the existence of trout.

“It’s definitely one of the best fisheries in Arizona, and to see it go away is heartbreaking, to say the least,” Trimble said.

temperature rises

Although trout fishing is still good, Trimble knows his days may be numbered as a trout fishing guide. The threat lies in the river in Lake Powell.

Water levels are historically low It means that the water flowing through the dam is getting warmer every week. Temperatures are usually in the high 40s and lows in the 50s. The water temperature last week was 64 degrees.

“Sixty-four fun people,” said Scott Rogers, director of the Arizona Aquatic Wildlife Division in the Northern Arizona District.

At 68 degrees and above, trout become lethargic and prone to death. Larger trout are particularly vulnerable.

Rogers said temperatures are expected to reach 69 or 70 degrees at Les Ferry this month.

“It’s a problem. We’ve been aware of that for a long time. We’re working with other agencies to do everything we can to try to mitigate what seems to be coming,” Rogers said.

Why is cold temperature important

Rainbow trout have a temperature of 68 degrees. But this is based on an ideal nutritional base. Colorado River fish usually eat midges and black flies, which are small particles of food. Stress can begin to occur inside rainbow trout at 68 or 69 degrees, which means the fish are “metabolic charged” and can tire very quickly.

The US Geological Survey is conducting surveys to determine how warm waters are affecting the food supply of fish.

Other Effects of Warmer River Water

Trout is not a major species. Its collapse is unlikely to have a cascading effect on other systems.

However, warmer waters also allow non-native bass and catfish to thrive. They can eat other fish and threaten native species.

“It’s hard to put that genie back in the bottle,” Rogers said.

Before the completion of the Glen Canyon Dam in the early 1960s, the water flowing through the Grand Canyon was as high as 85 degrees in summer. Rainbow trout was introduced into the Colorado River after the dam was built because the water was very cold throughout the year.

Good and evil in warm water

Like other wildlife destinations in the Southwest, the stripping of the area that federal scientists say is getting worse by climate change is changing what we’ve taken for granted for too long. Another consequence is the risk of trout losing control in Les Ferry.

“This is a critical fishery and one of the most important fisheries we have in the state and it will be a huge loss,” Rogers said.

When the temperature increase reached 59 degrees, there was a possible increase in humpback chub and other native fish populations in the Grand Canyon, according to the Department of the Interior.

However, the constant rise in temperature increases the risk of non-native cold/warm water fish such as brown trout, green sunfish, sea bass and walleye “which could have a devastating effect on the humpback chub populations in the Grand Canyon” , according to the Ministry of the Interior.

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