7354

• UCREFRP Catalog Number: 7354
• Author: Wydoski, R. S.
• Title: Biological Review of Endangered or Imperiled Fish in the Upper Colorado River Basin.
• USFW Year: 1985.
• USFW - Doc Type: Washington, D. C.
• Copyright Material: NO

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Table 2. Biological Summary of Rare Colorado River Fish (continued)
Item "tell Chub
Gila ele ans
Status/Distribution Numbers are extremely Endangered; Former range has been *xteemely reduced;
See Figure 3 for summary of distribution and
identification of sensitive areas.
Green River
n-67
Age and Growth I 55
(TL in sm) 11 100
III 158
IV 258
V 322
VI 355
VII 373
Maximum Size 457 mm
Maximum Age 7 years
Reproduction
Size/Age 426 = TL; Unknown
Fecundity hatchery; age II; n-24; average 4.677 (17.280/lb.)
hatchery; age III; n-ll; average 16.464 (23.940/lb.)
maximum 50.096 for wild fish
Spawning Period late Juee
Temperature at Spawning 18 - 20 C
Streamflow at Spawning Descending Hydrograph
Mater velocity unknown
Food Habits Feeds primarily on insects; observed feeding on terrestrial
insects floating on the surface in the Green River.
Habitat
Young - Collected from quiet backwaters.
Adults - Runs or glides with moderate current with a shifting
sand bottom; observed in about 1 meter of water in the
Green River during the late summer when feeding on
floating terrestrial insects.
Movement Movements of this fish have not been studied.
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