A report released this week confirms the presence of a rare native subspecies of trout in the upper areas of Bear Creek in southwestern El Paso County.
The trout, known as the greenback cutthroat, also is the official state fish of Colorado. It replaced the rainbow trout in 1994, after officials determined the rainbow was not a native species.
A research team at the University of Colorado-Boulder reached its findings by comparing the DNA of the greenback with that of other wild trout and from museum specimens dating back to the mid-1800s.
Bear Creek has the state's lone wild population of greenbacks, the team said. Before the research was announced, The Big Thompson River in Rocky Mountain National park was believed to have the state's only population.
The greenback is one of three remaining cutthroat subspecies in Colorado, the team said, and the Bear Creek population numbers around 750 along a four-mile stretch of the creek.
David Leinweber, owner of Angler's Covey, a fly-fishing shop in west Colorado Springs, said the research will create some excitement among fishermen, but more confusion.
"It really upset the apple cart," he said. "All of a sudden, fish that we thought were greenbacks, aren't. Fishermen who take pride in catching native fish will want to catch the ones in Bear Creek, but fishing is illegal there."
Greenbacks are listed as threatened under the Endangered Species Act.
The Center for Biological Diversity, an Arizona-based nonprofit conservation group, has sued the U.S. Forest Service regarding the research. The CBD said erosion from trails near the creek caused by off-road vehicles threatens the trout.
However, Doug Krieger, of Colorado Parks and Wildlife, said on Tuesday that the greenback population still appears healthy despite erosion, and the CPW is taking steps to protect the trout.
"We've put in some structures to keep that sediment from going into the stream and to keep more erosion from happening," he said. "Perhaps we'll relocate the trails in some places. There's no need to close the trails yet."
The greenback is native to the Platte River basin, not the Arkansas River basin where Bear Creek is located just west of Colorado Springs. Krieger said greenbacks are in the creek because Joseph C. Jones, who owned the land around the creek from 1884 to 1892, stocked the creek with trout from an unspecified hatchery in the area.
During the 1800s, the greenback's numbers declined due to human settlement, mining and competition from other trout species introduced to state waterways. The new research confirms that several trout species were removed from their native habitat and placed in other habitats within the state.
Krieger said Bear Creek's remote location, terrain and elevation helped protect it from competition with other trout species. He said the CPW had known since 2002 that the greenbacks had unique characteristics. As a result, the CPW removed 65 fish from the creek and began raising them in two fish hatcheries.
"We have about 1,000 fish, probably more than we have in the creek right now," said Krieger. "They'll be adults next year, and spawning. We'll stock them in their native South Platte basin late next year or early in 2014."
The research team also discovered two additional subspecies of cutthroat -- one of which is extinct -- raising the known historical total of subspecies in the state to six. The yellowfin, the only cutthroat native to the Arkansas River valley, is believed to be extinct since the early 1900s.
The greenback situation is reminiscent of Colorado's controversy with the Preble's meadow jumping mouse. The rodent's endangered status has been disputed for decades and has canceled many construction projects in order to protect its habitat.