6037

• UCREFRP Catalog Number: 6037
• Author: U.S. Fish and Wildlife Service.
• Title: Endangered Colorado River Habitat Utilization Curves-Draft.
• USFW Year: 1984.
• USFW - Doc Type: \
• Copyright Material: NO

Title: Colorado squawfish post-larval YOY velocity utilization
curve
Parameters: Mean column velocity (cfs)
Period: Year around
Location: All river reaches within post-larval YOY Colorado
squawfish distribution
Data utilized:
Mean column velocity data at point of capture for
1. Green River YOY sampling program 1980-82
2. Colorado River YOY standardized sampling program 1982-1983
3. Colorado River standardized sampling program 1979-1981.
Data excluded:
1. 1979 Green River YOY sampling program because velocity
measurements were not consistently taken.
2. 1983 Green River YOY because of abnormally high discharges
significantly altered habitats normally occupied by YOY Colorado
squawfish.
3. 1979-1983 standardized sampling program Green River and diel
sampling because more suitable data were available from the YOY
sampling program.
4.-,All Green River shoreline YOY sampling because catch
statistics indicate that YOY strongly prefer backwaters
rather than shoreline areas.
Assumptions:
I. Catch per unit effort reflects true mean column velocity
preferences.
2. Mean column velocities measured in seined areas reflect
true population preference.
3. No significant differences exist between spring and fall
velocity preference nor between Green and Colorado River
populations.
Constraints:
1. Applicable to only the Green and Colorado Rivers.
2. Represents only to backwater habitats.
3. Should apply only to stream channel models containing
backwater habitats.
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