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

' RESULTS AND DISCUSSION
During the first year of the study, 10 Colorado squawfish were captured
and implanted with radiotransmitters (Table 2). Of the 10 fish, two (B07 and
B09) were recaptured fish (fish that had been previously caught and tagged
with numbered Carlin tags). Fish (A10) was recaptured twice during the second
year of the study (Table 3). Radiotagged fish were monitored during ice
covered conditions from December 1986 through March 1987. There were 590.8
total observation hours on these 10 fish from which 118 hours (472 15-minute
observations) were used for analysis. Eight radictagged fish from the first
' year were still operational and were monitored during the fall 1987, but only
three (A10, All, and Bll) were operational into the second winter. During the
second year, 10 additional fish were captured and implanted with
radiotransmitters (Table 2). Of these 10 fish, four (BB7, C87, C95, and A91)
'were recaptures at time of implantation and two (B85 and C00) were recaptured
after winter monitoring. During Winter 2 from December 1987 through March
1988 there were 74 total observation hours from which 34.5 hours (138 15-
minute observations) were used for analysis. Three fish (A00, A91, and C95)
tagged during the second year were not located during winter monitoring but
were re-contacted in the spring 1988. During the first tagging trip for the.
' second year, tag B09 was located and transmitting on a gravel shoreline at FM
79.2. It is unlikely that the tag was expelled by the fish based on previous
studies that indicate radiotag retention (Tyus 1988 and Wick et al. 1983).
' Fishermen frequent the area where the tag was found and it is possible that
the tag was discarded during evisceration. This fish was originally caught
sharing this study for implantation by angling. Natural death cannot be ruled
' out: however, the fish had behaved normally during previous contacts. During
the second year, fish C93 apparently died in January 1988. This fish was
caught in October 1987 and was carrying a large, red and white Dardevil
embedded in the lower jaw.. Attached to the lure was 6 feet fishing line which
' had tangled around a small tumbleweed. The fish appeared underweight but
strong. Stress related to carrying this lure and of the implantation may have
been factors contributing to the cause of death. The fish behaved normally
after tagging until January but may not have been in good enough condition to
make it through the entire winter. This may indicate the importance of fall
feeding and conditioning prior to the winter period.
' Fish movement
Of the 20 fish implanted during fall months in the 2 year period, only
' three (A09, B07, and BB7) moved downstream and relocated aver 4 miles or out
of the study area after implantation. Fourteen fish remained within the study
areas in which they were tagged. The farthest moving fish (A09) was tagged at
' RNA 96.4 in the Government Bridge study area during fall 1986, and was located
15 miles downstream in the Maybell study area at RU 81.4, 3.5 weeks later
(Table 4). ly, A09 used the same embayment as four other
radiotagged fish. These downstream movements could have been due to
disorientation from the surgical process or the MS 222 anesthesia. However,
not all fish moved downstream after release, and some downstream movement may
be indicative of increased activity in the fall. B08 moved 4.4 miles in the
fall of 1987 but had been implanted the previous year, thus eliminating
implantation) disorientation as the cause. All fish that moved downstream in
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