Steamboat Springs Rainbow trout spawning areas, or redds, in a stretch of the Yampa River below Stagecoach Reservoir are protected under new regulations that went into effect Jan. 1, the Colorado Division of Wildlife reported this week.
Posted spawning areas in the Yampa are closed to fishing from the Stagecoach Dam downstream to Lake Catamount. DOW fisheries biologist Billy Atkinson said the ability to rope off the sensitive redds will allow him to refine management practices he is developing to return naturally reproducing rainbow populations to high levels that existed in the river in the late 1990s and early 2000s.
“My overarching objective is to see naturally repopulating rainbow trout in the river in the face of whirling disease,” Atkinson said. “There are very few major rivers in the state that offer that kind of fishing. It’s very rare in Colorado.”
He has previously closed spawning redds to fishing on a voluntary basis, he said.
Before 2002, Atkinson said, his stream census counts showed as many as 5,000 to 6,000 trout per mile of river in the tailwater below the dam. The metabolism of trout is more active on a year-round basis, and fish prosper where rivers pour out of dams. That’s because the water is warmer in winter and colder in summer, hitting the metabolic sweet spot for the cold-blooded fish.
However, the rainbow population in the Stagecoach tailwater crashed in 2001 and 2002, Atkinson said. He has a clear sense that the decline in trout was attributable to a whirling disease hot spot just downstream in Sarvis Creek. Whirling disease attacks the central nervous system of rainbow trout and is carried by spores of microorganisms in the water.
Atkinson identified a disease-resistant strain of European rainbows that are doing better in the Yampa below Stagecoach. But the scientist in him wants to understand all of the factors that could be depressing rainbow populations in the valuable stretch of water. That includes the possibility that damage is being done by anglers unwittingly wading through the redds in the crucial months from April, when trout eggs are deposited in the gravel, to the first week in July, when the freshly hatched trout emerge.
Atkinson said that in the past several years, he has ruled out fluctuations in water temperature, flows and oxygen levels from dam releases as factors that might have discouraged natural fish reproduction. In order to see whether wading fishermen are harming the redds, he will rope off sections of the river in summer to protect the eggs and hatching fingerling trout. The tentative plan is to leave the redds unprotected in spring 2012.
Subsequent stream census surveys will allow biologists to identify age classes of young trout and whether any are missing.
“If I see yo-yoing in age classes,” that will be confirmation, Atkinson said.
— To reach Tom Ross, call 970-871-4205 or e-mail tross@SteamboatToday.com