7610

• UCREFRP Catalog Number: 7610
• Author: Wick, E. J. and J. A. Hawkins.
• Title: Colorado Squawfish Winter Habitat Study, Yampa River, Colorado, 1986-1987
• USFW Year: 1987.
• USFW - Doc Type: Final Report Year 1.
• Copyright Material: NO

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RESULTS AND DISCUSSION
Squawfish captures
During October 1986, a total of ten Colorado squawfish were implanted
with radiotransmitters (Table 2).. Five fish were implanted at each of the two
study sites. Total effort expended in capturing these fish included 89.25
netting hours, 4.58 electrofishing hours, and approximately 8 hours of hook
and line. A capture report of related fish captures was submitted to the
Colorado Division of Wildlife under collecting permit number 86-0148. Two
Squawfish, B7 and B9, were recaptures. They were originally tagged in the
Yampa Canyon spawning area (RMI 9.5 and 18.4) in 1984.
Fish movement
During October and November the five Group A squawfish tagged near
Government Bridge (RMI 96.4-97.2) all relocated. Four fish (A7, A8, A10 and
All) which were all captured in eddy habitat in early October moved downstream
to a large pool area at RMI 95.7. Adjacent to the upper end of this pool, was
a large backwater. Fishes A7, A10, and All moved into this backwater in
November and utilized it almost exclusively throughout the winter (Table 3 and
Figure 3a). Shortly after ice-off on the last observation trip March 16-21,
this backwater area was breached by rising water and large ice flows which
altered its characteristics drastically. All radiotagged fish using it moved a
short distance downstream into main river habitats. Fish A8 relocated 3 miles
upstream in October and was found between RMI 97.9 and 98.8 throughout the
late fall and winter. During October A9 moved 15 miles downstream into the
Group B study area at Maybell (RMI 81.1-81.4) and remained there throughout
the winter. Contact with all the Group A fishes was maintained throughout the
winter schedule.
Group B fishes tagged between RMI 80.8 and 81.4 did not move as far. Fish
B7 moved downstream between RMI 76.2 and 76.3 and was located there throughout
most of the winter. Contact with B7 was not made on one scheduled trip January
5-9. Fishes B8, B9, and B11 were located between RMI 81.1 and 81.4 throughout
the fall and winter and were joined by A9 in showing preference for a large
embayment habitat at RMI 81.1. Fish B10 was the most unpredictable fish in the
B Group. It was located between RMI 80.8 and 81.9 throughout the winter,
however it was not found on two of the eight scheduled trips, Dec 1-6 and Feb
2-7 (Table 3 and Figure 3b).
Other than the extensive movements shortly following implantation in
October and November by two squawfish, movement was limited to river se m mts
less than_.two miles long during the W;n ov period December through
March. Analysis of the stationary, active, local, and moving catagories of
movement types indicated that there was little difference in'the level of
moveme Burin tjg four aily tim periods. Local movement was observed most
often dgy- the afernoon and evening.
Flow, temperature, and ice thickness
Flow levels during the winter study ranged from 200-2300 cubic
feet/second. Lowest flows occurred when the maximum river temperatures
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