BOARD02169

• Board Meeting Date: 5/24/1999
• Description: Endangered Fish Recovery, ISF Water Rights Applications - 15-Mile Reach and Yampa - Status Report
• Board Meetings - Doc Type: Memo

Endangered fish population status and recovery goals

The largest minnow in North
America and one of the largest in
the world, the Colorado
pikeminnow can live 50 or more
years. Historically, this fish grew to
lengths of nearly 6 feet and weights
of up to 100 pounds.

Colorado pikeminnow (formerly called the Colorado squawfish, but renamed in 1998 by
the American Fisheries Society); In the Green and Colorado river basins, Colorado
pikeminnow populations are increasing, in part because of changes made by Recovery
Program participants in the operation of Flaming Gorge Dani and coordinating spring-time
flows in the Colorado River. The largest numbers of Colorado pikeminnow are in the Green
River. In fact, biologists now are finding more adult pikeminnow in the Green than at any
other time since monitoring began in the early 1980s. In the Colorado River, the number of
pikeminnow has doubled just since 1991. Elsewhere, Colorado pikeminnow populations are
relatively small, but stable. '

Small numbers of larval pikeminnow were captured in 1995 in the Gunnison River upstream
of the Redlands Diversion Dam and in the Colorado River's Grand Valley. Completion of the
Redlands Fish Ladder has enabled 42 Colorado pikeminnow to migrate upstream to Gunnison
River habitat, which should further boost their recovery potential. Recovery management
objectives call for about 5,500 fish in each of two stretches of the Green River and one stretch
of the Colorado River. Because pikeminnow populations appear stable within the State of
Colorado, the Colorado Division of Wildlife has down-listed this species from "State-
endangered" to "State-threatened."

The pronounced hump behind its
head gives the humpback chub a
striking, unusual appearance. This
fish can grow to nearly 20 inches
and may survive more than 30 years
in the wild.

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. Primary recovery areas in the upper basin
include: Black RockslWestwater Canyon of the Colorado River near the Colorado-Utah state
line; the Yampa and Green livers in Dinosaur National Monument; Gray and Desolation
canyons in the Green River; and Cataract Canyon in the Colorado River. Management
objectives for the humpback have been set at about 4,800 fish in five different areas of the
Yampa, Green, and Colorado rivers.

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