7360

• UCREFRP Catalog Number: 7360
• Author: Tyus, H. M. and G. B. Haines
• Title: Distribution, Habitat Use, and Growth of Young Colorado Squawfish in the Green River Basin, Colorado and Utah
• USFW Year: 1989
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

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14.1
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66.5
1.6

12.5
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10.8
45.6

15.9
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24.8 0.0
17.9 6.4

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BIOLOGY OF YOUNG COLORADO SQUA WFISH

83

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150 JUL Y I AUGUST
120
90
60
30
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"- 32 96 160 224 352 416 480 544
I
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50 SEPTEMBER/OCTOBER
40
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96 224 416
KILOMETERS

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FIGURE 2.-Average catch of age-O Colorado squawfish in backwaters per 100 m2 seined in the Green River,
July-August 1981 and 1984-1988 (upper) and September-October 1979-1985 and 1987-1988 (lower). Distance
is measured from the Colorado River.

TABLE 2.-Hatchin$ dates of larval Colorado squawfish captured in the Yampa and Green rivers. Dates were
calculated from total lengths of fish and capture date by use of equations of Haynes et al. (1984) and Nesler et aL
(1988); N = number offish.

One concentration OCCulTed be- Yampa and upper Green rivers Lower Green River
.d 450, or about 150 km down- Year Mean Range" N Mean Range" N
Canyon spawning area; another
n downstream of Gray Canyon 1981 Jun 29 Jun I3-Jul 6 36 Jun 20 Jun I3-Jul 4 24
nd 1.60). However, as in the July 1982 Jul14 Jul IO-Jul 22 98
1983 Jul28 Jun 22-Aug 3 91
:s, highest numbers OCCulTed ei- 1984 Ju130 Jul IO-Aug 6 33 Jul5 Jun 26-Jul 16 19
r lower Green River depend' 1985 Jul5 Jun 27-Jul 14 183 Jul6 Jun 25-Jul 13 95
. ,mg 1986 Jul20 Ju1 9-Jul 27 30 Ju124 Jul 9-Aug 2 426
~. HIgher ~tches generally oc- 1987 Jun 28 Jun II-Jul 16 745 Jun 30 Jun IO-Jul 16 1,490
lent reaches, including strata A 1988 Jul8 Jun 22-Jul 16 450 Jul6 Jun 22-Jul 16 252
, 12.4/100 m2 seined). Higher~ a Range = dates that included 90% of the sampled fish.