Drought, heat, fire force fishing ban on Colorado River

DENVER (AP) — Colorado wildlife officials on Wednesday urged anglers to avoid fishing along a stretch of the Colorado River because low flows during a historic drought in the U.S. West, critically warm water temperatures and sediment runoff from wildfire burn scars are all starving trout of oxygen.

The move along a 120-mile (193-kilometer) stretch of the river — unusual so early in the summer — is another consequence of the record heat and drought that’s afflicted the American West. The voluntary fishing ban runs from the town of Kremmling in north-central Colorado to Rifle in the western part of the state.

“The extreme drought on the Western Slope, plus the sediment and debris in the waterway, have created a really challenging situation for fish,” said Travis Duncan, spokesman for Colorado Parks and Wildlife.

River temperatures reaching and surpassing 70 degrees Fahrenheit (21 Celsius) pose a threat by depleting oxygen levels and possibly feeding algae blooms. Rainbow and brown trout in the Colorado River, which thrive in temperatures between 50 and 60 F (10 and 16 C), become lethargic and often stop feeding, Duncan said, and wildlife officials have seen evidence of the fish dying in parts of the river.

“We’re asking folks to voluntarily refrain from fishing,” he said. “If the conditions persist, we’ll need to adopt a mandatory ban.”

Colorado River flows at two U.S. Geological Survey monitoring stations are less than half of historic levels, state wildlife officials said. At an upstream site, a Geological Survey gauge has been measuring between 600 and 700 cubic feet per second, compared with a typical 1,500 to 2,000 cubic feet per second.

Flows at a downstream gauge are about 1,250 cubic feet per second, compared with an expected 3,000 to 4,000 cubic feet per...