7908

• UCREFRP Catalog Number: 7908
• Author: Valdez, R. A. and R. J. Ryel.
• Title: Life History and Ecology of the Humpback Chub ‎(
• USFW Year: 1995.
• Copyright Material: NO

List of Figures

Fig. 1. Annual discharge (WY 1922-92) and mean daily predam (WY 1922-62) and
postdam (WY 1965-92) flow of the Colorado River at Lees Ferry, AZ. . . . . . . . . . . . . . . 1
Fig. 2. Mean monthly water temperature at Lees Ferry following closure of Glen Canyon
Dam and impoundment of Lake Powell on March 13, 1963. Monthly means are
based on measurements at 15-min intervals. Suitable spawning temperature range
for humpback chub is shown at 16-220C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Fig. 3. Relationship of flow to Secchi depth during a transition of high fluctuating releases
(7,000-25,000 cfs) to constant 5,000 cfs, May 10-23,1991. .....................2
Fig. 4. Locations of nine aggregations of humpback chub with percentage of adults
captured in the Colorado River in Grand Canyon ............................. 3
Fig. 5. Number of species, species diversity, and biomass of native and non-native fish
species by geomorphic reach from Lees Ferry to Diamond Creek. Data for Glen
Canyon Dam to Lees Ferry (GC-LF) from Arizona Game and Fish Department

(1993). ............................................................. 4

Fig. 6. Fidelity of 60 PIT-tagged humpback chub in the mainstem Colorado River following
presumed spawning in the LCR, October 1990-November 1993. ................. 7
Fig. 7. Monthly geometric mean catch per effort, CPE (GMa>e # fish/100 ft/100 hr) for adult
humpback chub captured in nets within RM 60.0-61.9 (LCR Inflow), 1991-93.
Standard error bars are shown. ................,.........................8
Fig. 8. Fraction of telemetry observation time blocks with horizonal movement of radio-
tagged adult humpback chub in Region I during average research and interim flow

cycles. ....................",........,............................. 9

Fig. 9. Length-frequency distribution of humpback chub captured in shoreline habitats
(with electrofishing, seines, minnow traps) and in offshore habitats (with gill nets,
trammel nets) for 1991-93. .... . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Fig. 10. Average depth (A) and velocity (B) at three distances from shore (0.5, 1.5 and 2.5
m) for six shoreline types in Subreach 1 (RM 61.9-65.4) and Subreach 2 (RM 65.4-

73.4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Fig. 11. Radio contact locations for adult radio-tagged humpback chub at two sites in the
mainstem Colorado River. ............................................. 11
Fig. 12. Volumetric composition of invertebrates (excluding Cladophora) found in stomach
contents of adult humpback chub from the Little Colorado River aggregation and
the Middle Granite Gorge aggregation during 1992-93. . . . . . . . . . . . . . . . . . . . . . . . . 12
Fig. 13. Logarithmic growth curve for humpback chub in the mainstem Colorado River in
Grand Canyon (A). Hatching length of 7 mm from Muth (1990); length at 1-3 years
from scale back-calculations; lengths at 50 mm increments for 4+ years from PIT
tag recaptures. Growth curve for humpback chub in the LCR (B) from Minckley

(1992) ............................................................ 13

Fig. 14. Suitable and optimal temperature range for spawning by humpback chub compared
to predam temperature of the Colorado River at Phantom Ranch (A), and the
temperature of the LCR and postdam Colorado River at Glen Canyon Dam, LCR,
and Diamond Creek (B). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Fig. 15. Potential daily and annual consumption of humpback chub by adults of three
predator fish species in the Colorado River in Grand Canyon. Relationships
assume 2.0 chubs consumed daily by 10.4% of adult brown trout; 1.0 chub
consumed daily by 1,5, or 10% of adult rainbow trout; 1.0 chub consumed daily by
1.5% of adult channel catfish. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Fig. 16. Life history schedule for the LCRI aggregation of humpback chub in the mainstem
Colorado River in Grand Canyon. ...................................... . . 18