7195

• UCREFRP Catalog Number: 7195
• Author: Nesler, T. P., R. T. Muth and A. F. Wasowicz
• Title: Evidence for Baseline Flow Spikes as Spawning Cues for Colorado Squawfish in the Yampa River, Colorado
• USFW Year: 1988
• USFW - Doc Type: American Fisheries Society Symposium
• Copyright Material: YES

SPAWNING CUES FOR COLORADO SQUAWFISH
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2so 1986 so
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20 25 30 5 10 15 20 25 30 5 10
JUN -JUL AUG
FIGUxE 3.-Relationships of estimated Colorado squawfish spawning dates (vertical bars) to Yampa River flow
regimes (curves) at the U.S. Geological Survey's Maybell and Deerlodge gages for 1983-1986. Number of fish
represents number sampled and distributed according to estimated spawning date.
Figure 1). Months of record were selected to
bracket the known Colorado squawfish spawning
seasons as reported in existing literature. The
years of record selected represented the available
flow data for the Yampa River and were used to
characterize the historical flow regime during the
spawning season. Water temperatures were also
obtained from USGS data collected at the May-
bell gage. Precipitation data for the region includ-
ing Dinosaur National Monument, Colorado,
were compared to the Yampa River flow regime
during June-August, 1980-1986, to determine the
relationship between rainfall and flow spike
events. Daily rainfall data were provided in
NOAA (1980-1985, 1986).
Results
The frequency distribution of Colorado
squawfish spawning dates for each year during
1983-1986 demonstrated prominent peaks in
spawning activity (Figure 3). In 1983, peak
spawning activity began July 24-25 and was
closely related to the flow spike occurring July
22-25. Flows at Deerlodge increased from 89.7
to 122 m~/s. Peak spawning activity in 1984
began July 8, and was associated with the flow
spike occurring July 9-11. Flows at Deerlodge
increased from 162.1 to 233.5 m3/s. In 1985, two
peaks in spawning activity were ,evident and
appeared closely related to two major flow
spikes. The first peak in spawning activity began
June 25, and was associated with the flow spike
occurring June 25-27. Flows at Deerlodge in-
creased from 108.5 to 136 m3/s. The second peak
in spawning activity began July 23, and was
associated with the flow spike occurring July 19-
22. Flows at Deerlodge increased from 27.6 to 66
m3/s. In 1986, peak spawning activity began July
10, following the flow spike occurring July S-7.
Flows at Deerlodge increased from 98.9 to 129.2
m'/s. In these five cases, spawning peaks were
associated with flow spikes of 27.5-71.4 m3/s
occurring over a 2-3-d period. These spikes
represented 25-139% increases in river flow.
No prominent spawning peaks by Colorado
squawfish were evident during 1980-1982 (Figure
4). In these 3 years, only 20-46 larvae were
collected, compared to 124-455 in 1983-1986
(Table 1). As a result, only the range of spawning
dates may be compared to the flow regime. In
1980 and 1981, onset of spawning appeared to be
loosely associated with the occurrence of flow
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