Taylor Hawes Pictured from the air in the summer of 2009, the Yampa River winds through the 910-acre Carpenter Ranch, owned by The Nature Conservancy and protected permanently under a conservation easement.
another critical function, says Tom Chart, a U.S. Fish and Wildlife Service fisheries biologist who directs the Upper Colorado River Endangered Fish Recovery Program: it provides cues for endangered and native fish that are essential to their spawning behavior. The fish sense when the flows are rising and water temperatures warming, prompting them to head for their traditional spawning grounds. “That natural hydrograph is something we have really tried to promote with our recovery program,” Chart says. The endemic Colorado pikeminnow, which co-existed with dinosaurs millions of years ago, uses the high flows to migrate toward very discrete spawning areas in the upper basin, says Chart. The fish journey more than 200 miles to the riffles and gravel bars of the Yampa Canyon and the middle Green River, just below the Yampa convergence. Here, they commence spawning as soon as the flows start to drop off and the river begins to warm, conditions that would be compromised with any large-scale future diversions on the Yampa, says Harrison.
Recovery program intervention At one time, healthy populations of Colorado pikeminnow lived 50 or more years, growing to 6 feet and weighing up to 80 pounds. According to Chart, the feisty fish, valued for food and sport by early settlers, is starting to rebound on the Green. Chart attributes some of its recovery to his program’s efforts to remove non-native fish from its habitat and to better manage flows entering the Green. But he added that the population may wane again as it responds to environmental conditions, including flow rates and water temperatures. “The Yampa is still reeling from the drought that occurred in the early 2000s,” says Chart. “The whole fish community
“Riparian vegetation helps form the basis of the food chain—the leaves and branches that drop into the river become organic material for small bugs, which work their way up the food chain for fish and other aquatic species to eat.” —John Sanderson
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