7346

• UCREFRP Catalog Number: 7346
• Author: Wick, E. J. and J. A. Hawkins.
• Title: Colorado Squawfish Winter Habitat Study, Yampa River, Colorado 1986-1988.
• USFW Year: 1989.
• USFW - Doc Type: Fort Collins, Colorado.
• Copyright Material: NO

cobble substrates are used for spawni.nq (Wick et al. 1983 and 1985). Spawning
0 '
0) (Tyus et al. 1987).
occurs at an average temperature of 22oC (range 15-27.5
After spawning, most Colorado squawfish return to their pre-spawning migration
locations. During low-flow periods of August to early November, squawfish use
pools along with run, eddy, and quiet shoreline areas (Wick et al. 1983 and
1986).
This study of Colorado squawfish winter habitat requirements resulted

from Section 7 consultation pursuant to provisions of the Endangered Species '
Act of 1973. This consultation involved the Bureau of Reclamation (BOR) and
the United States Fish and Wildlife Service (USFWS), regarding construction of
Stagecoach Reservoir on the upper Yampa River near Steamboat Springs, Colorado
by the Upper Yampa Water Conservancy District (UYWCD). Inpacts on end,&?ed
species (primarily Colorado squawfish) fram the project could occur during the
winter months. Although adequate data have been previously collected on ,
migration, spawning requirements, habitat preferences, and flow needs of
Colorado squawfish during spring, summer, and early fall: no data had been
collected on habitat requirements and behavior during the winter. Information

on the winter habitat needs of Colorado squawfish would assist USFWS in making '
winter flow OnS.
After coWleticn of the first year of the winter study from December 1986
through March 1987 (Winter 1), additional funding was provided by the Bureau
of Reclamation to radiotrack squawfish during fall months. This allowed field
work to begin earlier in 1987, providing an opportunity to collect habitat use
information during the fall on the Yampa River, and ensured a smooth '
transition into the second winter from December 1987 through March 1988
(Winter 2). Funding was also provided to track squawfish through Spring 1988
to assist USFWS in determining movement and habitat use patterns during spring

months and when spawning migrations began into Yampa Canyon. ,
We also cooperated with the Colorado Division of Wildlife (CDOW) on a
study of northern pike spawning behavior and habitat use on the upper. Yampa
River. This study was conducted to gather preliminary information on haw ,
extensively northern pike and Colorado squawfish utilize the same habitat
types.
The objectives of this investigation were to:
1. Determine if adult Colorado squawfish remain in specific river segments
from fall to early spring in the upper Yampa River. '
2. Determine habitats and microhabitats (depth, velocity, substrate,
t exOtt , and cover) used by Colorado squawfish during fall and
winter months.
3. Develop fall and winter habitat utilization curves based on mi-crohabitat
data (Bovee 1986) collected during the study.
4. Evaluate the applicability of the Physical Habitat Simulation (PFIMIM)

model to determine flow requirements during winter months for Colorado ,
squawfish on the Yampa River.
5. Track Colorado squawfish during spring 1988, to determine habitat use
and time of spawning migration into Yampa Canyon. ,