8206

• UCREFRP Catalog Number: 8206
• Author: Miller, W. J. and D. E. Rees.
• Title: Colorado Squawfish habitat use and movement during summer low flow in the Yampa River upstream of Cross Mounatin Canyon. Final Report.
• USFW Year: 1997.
• USFW - Doc Type: Fort Collins, Colorado.
• Copyright Material: NO

DISCUSSION
Flows
Flow volume in the Yampa River in 1996 was approximately 1,000 cfs at mid-July when fish
capture and implementation began. It dropped to 79 cfs on September 6 and then rose back up to
close to 400 cfs by late October, at the end of the study. The river flow was less than 100 cfs for
two days, September 5 and 6. Typically, flow drops to a minimum in September but increased
by October. The 1996 summer flows are low compared to most years.
Flow magnitude in the Yampa River in 1997 was much higher than observed in 1996. Flows in
late July were approximately 1,000 cfs, compared to 600 cfs in 1996 but flow remained over 700
cfs for the majority of July and August and was up to 1,650 cfs during the second week in
August. Minimum base flow in the summer of 1997 was observed on September 12 and 13 at
320 cfs. By September 18, a rainstorm in the upper Yampa caused an increase in flow to nearly
7,000 cfs in the study area. Flow remained over 1,400 cfs to the final week of observations in
1997. Fish response to flows in 1997 showed that the peak flow with high sediment caused most
of the fish to move downstream some distance from their observed locations for the majority of
the summer. This response was shown for all observed squawfish during the week with the high
flows.
Radio Telemetry
Colorado squawfish exhibited both local and long distance movement patterns throughout the
study. One fish moved approximately 7 miles upstream and then moved downstream 6%i miles
in 1996. This particular fish moved upstream during a time when flows were lowest in the
summer and moved back downstream in the fall at higher flow rates. Apparently the 1996 flows
did not prevent the upstream movement through shallow riffles or the Patrick Sweeney Diversion
structure. Other fish in 1996 moved locally and stayed within the same river mile.
On most 24 hour observations there were local movements of several hundred feet by the fish
that were being observed with movement peaking after dusk. Movement activity increased after
dark with fish moving either upstream or downstream to a probable feeding location and then
returned to the original observation point.
Channel catfish and northern pike showed little movement during the study. Most of these fish
remained in the same river mile where they were originally captured with the exception of two
channel catfish that moved downstream approximately 4 miles at the late October observation
period. One was observed by the ground crew; the other was observed only by air contact.
During the only 24 hour observation of a northern pike, the fish exhibited similar local
movement as the Colorado squawfish. Activity increased after dusk. The fish moved upstream
several hundred feet. That movement peaked just before midnight and the fish returned back to
its original location before dawn the next day.
Final Report - Colorado squawfish habitat Page 72
Miller Ecological Consultants, Inc. December 17, 1997