1006

• UCREFRP Catalog Number: 1006
• Author: Resource Consultants, I.
• Title: Biological Assessment Green Mountain Reservoir Water Marketing Program.
• USFW Year: 1985.
• USFW - Doc Type: Denver.
• Copyright Material: NO

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SPECIES DISCUSSIONS

FISH

Colorado Squawfish
Distribution, Abundance, and Ecology:
The Colorado squawfish is presently found only in the Colorado River
system above Glen Canyon Dam (Lake Powell). It was once found through-
out the entire basin in all main channels and larger tributaries, but
has become extinct below G1 en Canyon Dam and in the Green River above
Flaming Gorge Dam. In the upper Colorado River, the squawfish is found
from Lake Powell upstream to near the Government High1ine Dam near
Palisades, Colorado (Figure 2), which is an effective barrier to
upstream fish migration (Valdez et a1 1982). It is probable that its
earl ier distribution incl uded the river at least to De Beque and pro-
bably upstream to Rifle. Sampling above the Government Highline Dam has
been sporadic and not nearly as intensive as studies below this barrier.
Therefore, there is a very slight chance that a few adult squawfish may
still exist in the De Beque area, but none have been collected. Adult
squawfish are also found in the lower Gunnison River, a tributary of the
Colorado River near Grand Junction.
Adult Colorado squawfish are generally rare in the Colorado River,
but can be locally abundant in certain habitats at certain times of the
year (Valdez et al 1982). Adults are most corrmon in the 'upper Colorado
River near Grand Junction. Juvenile squawfish are principally found
below Moab, Utah on the lower portion of the Colorado River, and are
a 1 so quite unconmon, although 20 to 30 young-of-the-year are at times
found in one habitat (Valdez et a1 1982). Larval squawfish have been
found in both the upper (Grand Junction area) and the lower (Moab area)

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