7106

• UCREFRP Catalog Number: 7106
• Author: Ferriole, S.
• Title: Wildlife Resource Information System
• USFW Year: 1987.
• USFW - Doc Type: Colorado Squawfish Mapping Criteria for the Colorado, Dolores, Gunnison, Green, White, and Yampa Rivers.
• Copyright Material: NO

Range of Reproduction

t
Colorado squawfish reproduction appears restricted to the
lower 32 km (20 mi} of the Yampa River in Colorado (Haynes et al.
1985), parts of the Green River in Utah (USFWS 1984c, Valdez et al.
1986), and parts of the Colorado River in .Colorado and Utah (Archer
~.. et al. 1985, Valdez et al. 1986). Only two specific spawning sites
have been identified for Colorado squawfish: Three Fords on the
Green River in Utah, and the lower Yamga River (USFWS 1984c).
Reproduction was believed to occur in the San Juan River based on
the collection~of a juvenile there in 1978 (Minckley and Carothers
1979}. This belief was confirmed when young-of-year specimens were
found in the-river in 1987 (D. Probst, New Mexico Game and Fish
Dept.; pers. comm.). Regardless of evidence confirming
reproduction, recruitment may not be adequate (Tyus et aI. 1985);
juvenile specimens are rarely found.
Habitat Use
Colorado squawfish are wide ranging and require a variety of
habitats throughout their life cycle (Wick et al. 1983).
Post-larval, age-0 Colorado squawfish are most often found in slower
river reaches (Archer et al. 1985) and in backwaters that have silt
substrates and little or no current (Holden 1977x, Miller et al.
1982c). Most juvenile an d. age-0 Colorado squawfish are found in
middle and lower reaches of the Upper Colorado Basin (mainstem Green
' River, Colorado River in Utah) (Miller et al. 1982c). Most adult
Colorado squawfish are found in upstream river reaches (Yampa River,
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