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 depth utilization curve.
Parameters: Total water column depth (ft)
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 observatons of 30 min. or more
duration 1980-84.
Data excluded:
1. All Green and Yampa River capture location data because of
extensive data base for direct radio location observations which
is believed more definitive.
2. All Green and Yampa River data collected during spawning
migrations because they were believed not to reflect true habitat
preferences.
3. All radio observations during the spawning period were excluded.
because separate curves were deve-loped for that life stage.
4. AlI radio observations in flooded bottoms were excluded because
they did not reflect within channel habitat selection.
Assumptions:
1. water column depth at capture sites and radio locations reflect
adult Colorado squawfish preferences for depth.
2. Adult Colorado squawfish in the Colorado, Green and Yampa Rivers
exhibited similar depth preferences.
3. Depth greater than 2.95 ft. is not a limiting factor.
Constraints:
1. Curves apply to adult Colorado squawfish in occupied reaches of
the Green, Yampa and Colorado Rivers.
Curve coordinates:
X (ft ) Y (SI )
.75 0.0
1.5 0.1
2.5 0.5
2.95 1.0
10.0 1.0