7984

• UCREFRP Catalog Number: 7984
• Author: Maddux, H. R., L. A. Fitzpatrick and W. R. Noonan.
• Title: Colorado River Endangered Fishes Critical Habitat - Draft, Biological Support Document.
• USFW Year: 1993.
• USFW - Doc Type: Salt Lake City, Utah.
• Copyright Material: NO

CURRENT DISTRIBUTION AND ABUNDANCE
Native populations of the Colorado squawfish are restricted to the Upper Basin in Wyoming,
Colorado, Utah, and New Mexico. The species occurs in the Green, Yampa, White,
Gunnison and Colorado rivers (Holden and Wick 1982; Miller et al. 1982b; Tyus et al.
1982b; Wick et al. 1985, 1986; Archer et al. 1985; Tyus et al. 1987; Burdick 1993; Valdez
and Cowdell 1993). Colorado squawfish populations have been extirpated from the Lower
Basin.
Catches of young, juvenile, and adult Colorado squawfish are higher in the Green River sub-
basin of Colorado and Utah than elsewhere (Tyus 1991a). Recent investigations have found
many young, juveniles, and adults in the Green River from the mouth of the Yampa River to
its confluence with the Colorado (Holden 1973; Holden and Stalnaker 1975a, 1975b; Tyus et
al. 1982a, 1987; Tyus and Haines 1991).
Adult Colorado squawfish have been captured in the lower 124 miles of the Yampa River
and in Lodore Canyon of the Green River (Tyus et al. 1982a; Miller et al. 1982b), and
larvae were identified from the lower 19 miles of the Yampa River in Dinosaur National
Monument (Wick et al. 1981, 1985, 1986; Haynes et al. 1984; Tyus and Haines 1991). Two
adult Colorado squawfish implanted with radio transmitters ascended the Little Snake River
in 1988 (Wick and Hawkins 1989). Investigation of the Green and Little Snake rivers in
Wyoming in 1986 failed to produce any Colorado squawfish, (Johnson and Oberholtzer
1987); however, an adult was found in the Little Snake River in Wyoming in 1990 (Marsh et
al. 1991).
Colorado squawfish have been found in the lower 151 miles of the White River in Utah and
Colorado (Prewitt et al. 1978; Wick et al. 1979, 1981; Carlson et al. 1979; Lanigan and
Berry 1981; Miller et al. 1982a; Martinez 1986a). In the Duchesne River, a fisherman
caught a Colorado squawfish at the mouth of the Uinta and Duchesne rivers in 1975
(Seethaler 1978) and a specimen implanted with a radio transmitter ascended the Duchesne
River in 1980 (Tyus et al. 1982b).
Colorado squawfish have been collected above and below the Redlands Diversion Dam on
the Gunnison River (Valdez et al. 1982a; Wick et al. 1985; Osmundson and Kaeding 1989;
USFWS 1992a); adults have been captured above this diversion as recently as the spring of
1993 ( Bob Burdick per. comm.) Colorado are regularly collected in the Colorado River
between the Price-Stubb Dam near Palisade, Colorado and Lake Powell (Valdez et al. 1982a;
Osmundson and Kaeding 1989; Valdez and Cowdell 1993).
Adult and juvenile Colorado squawfish have been captured in Lake Powell (Minckley 1973;
Wick et al. 1981; Valdez et al. 1982b; Miller et al. 1984). Adult Colorado squawfish were
captured in the riverine portion of the reservoir in 1980 (Persons and Bulkley 1982). Valdez
(1990) also reported both adult and juvenile Colorado squawfish in Cataract Canyon at the
inlet of Lake Powell, indicating that the species is reproducing in or above that reach.
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