Briefing Paper to Accompany the Proposed Upper Colorado River and San Juan River Endangered Fish Recovery Act of 1997

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Fish population status and recovery goals Upper Colorado River Recovery Program Colorado squawfish The largest numbers of Colorado squawfish in the Colorado River Basin are in the Green River, where their numbers may be rising. Populations in the Colorado and Yampa rivers are small but appear stable. Elsewhere, Colorado squawfish populations are small, although several recent discoveries have been made: A handful of larval squawfish were captured in 1995 for the first time in the Gunnison River upstream of the Redlands Diversion Dam and in the Colorado River's Grand Valley in 1995. A small number of young squawfish were discovered about 30 miles up the Price River in Utah in 1996. Recovery goals for this fish species are to establish naturally self - sustaining populations in the Green River and Colorado River sub - basins. Humpback chub In the Green and Yampa rivers, humpback chub populations are very small, but appear stable. A population in the Colorado River near the Utah- Colorado state line is relatively large and appears healthy and stable. Recovery goals are to establish five self - sustaining wild populations and protect their habitat. Primary recovery areas in the upper basin include: Black Rocks /Westwater Canyon of the Colorado River near the Colorado -Utah state line; the Yampa and Green rivers in Dinosaur National Monument; Gray and Desolation canyons in the Green River; and Cataract Canyon in the Colorado River. Razorback sucker Biologists recently discovered a spawning population of razorback suckers in the lower Green River. However, most razorbacks captured in recent years in the Green, Colorado and Yampa rivers are thought to be more than 20 years old, with very little known "recruitment" of young fish into the adult population, meaning few young are surviving to adulthood. Razorback populations are considered critical. The first priority for the razorback is to prevent their extinction in the wild. Bonytail The bonytail is the rarest of the four endangered fish. Captive populations of bonytail are being maintained at Horsethief State Wildlife Area in Colorado and at the Wahweap Hatchery in Utah. About 2,000 of the bonytails from Wahweap were stocked in the Colorado River in both 1997 and 1996. The primary recovery goal for the bonytail is to prevent extinction in the wild.