By waving an electronic bar code-like scanner under the belly of the fish, U.S. Fish and Wildlife Service researchers identified it as No. 1F41386206, which Utah fishery biologists had captured in 1995 in the Colorado River near Moab. In addition to the four endangered fish, to date nearly 15,000 other native fish, such as flannelmouth suckers, bluehead suckers and roundtail chubs, have passed through the structure, reaching portions of the Gunnison River that had been off-limits for nearly a century. We want to prevent that from happening in the upper Basin before the numbers of fish get too low. Before the ladder was built, when Gunnison River water reached the Redlands Diversion Dam, it all spilled over the top. Now, a flow of 25 cubic feet per second is diverted through the fish ladder.
Biologists then sort and count the fish before releasing endangered and other native fish upstream.