About 20 volunteers from the Five Rivers chapter of Trout Unlimited on Saturday breached beaver dams to lay the foundation for extending the range of the native Colorado River cutthroat to the upper reaches of the Hermosa Creek watershed.

Breaching the beaver dams will allow treatment of Hermosa Creek tributaries with Rotenone to kill non-native fish, to be followed by the stocking of native cutthroat.

One main reason to extend the range of the native species is to keep it from being listed as threatened by the Environmental Protection Agency. Listing would bring restrictions on recreational and economic activities in the watershed.

On Saturday, the volunteers breached the beaver dams and then installed “beaver deceivers,” perforated pipes that frustrate the effort of beavers to reblock streams.

daler@durangoherald.com