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: Adult Colorado squawfish nonspawning velocity utilization curve.
Parameters: Mean column velocity (cfs)
Period: 1 Sep - 30 Apr
Location: All river reaches within adult Colorado squawfish distribution.
Data utilized:
1. Colorado River adult Colorado squawfish captures for all years
1979-1984.
2. Green and Yampa River radio observations of 30 min. or greater
duration 1980-1984. These data were increased by a multiple of
two to provide mean column velocities to more accurately reflect
hydraulic velocities modeled in the area of the fish. This was
necessary because microhabitat velocities used by the fish are
only about 1/2 the mean column velocity represented by associated
cells in the hydraulic model.
Data excluded:
1. All Green and Yampa River data collected during spawning
migrations because it was felt that true habitat preferences were
not exhibited during that period.
2. All spawning period observations were excluded because curves
were developed separately for that life stage.
3. All radio observations in flooded bottoms because they do not
reflect within channel habitat selection.
Assumptions:
1. Mean column velocity at the capture location and/or observed
radio location reflects Colorado squawfish velocity preference.
2. Colorado squawfish velocity preferences in the Colorado, Green
and Yampa Rivers are the same.
Constraints:
1. Applicable to the Green, Yampa and Colorado Rivers occupied by
adult Colorado squawfish.
Curve coordinates:
X (ft/sec ) Y (SI )
0.0 .25
0.2 1.0
2.0 1.0
. 6.0 0.0