Click the link to read the article on the Associated Press website (Brittany Peterson). Here’s an excerpt:
Key Colorado River reservoirs Lake Powell and Lake Mead are both only about one-quarter full. The continued drop, due to overuse and an increasingly arid climate, is threatening the fish and the economies built around them…since late August, the water temperature at Lees Ferry — the site of a world-famous trout fishery — has risen above 70 degrees seven times. That might be idyllic for a summer dip under the blazing Arizona summer sun, Gunn said, but approaches peril for the beloved sport fish. A few degrees higher can be lethal. To make matters worse, when temperatures rise, the amount of oxygen dissolved in the water falls, making it tough for fish to even breathe.
As the reservoir drops, it sends warmer water with less oxygen into the river below the dam. Should that water reach 73 degrees, [Terry] Gunn said his family’s guide service could start calling off afternoon trips…
Just a few miles north of Lees Ferry and its trout fishery there’s another threat — nonnative predatory smallmouth bass. They’re supposed to be contained in Lake Powell. But this summer they were found in the river below the dam. Smallmouth bass already wreaked havoc on native fish way upriver where the government spends millions of dollars each year to control the predators. They were held at bay in Lake Powell because Glen Canyon Dam has served as a barrier for them for years — until now. The reservoir’s recent sharp decline is enabling these introduced fish to shoot through the dam and edge closer to the Grand Canyon, where the biggest groups of humpback chub, an ancient, threatened, native fish, remain.