9432 ‎(2)‎

• UCREFRP Catalog Number: 9432
• Author: Modde, T. and M. Fuller.
• Title: Feasibility of Channel Catfish Reduction in the Lower Yampa River.
• USFW Year: 2002.
• USFW - Doc Type: Vernal.
• Copyright Material: NO

upstream displacement was 61.1 miles (mean of 10.9 miles for 11 fish). Final
displacement was also predominantly downstream (mean=7.1 miles) compared to mean
upstream final displacement of only 0.9 miles (Appendix; Table K.1.). For fish
that radio contact was maintained for over 200 days, three fish (Codes 79, 93,
and 96) were ultimately found less than 2 miles from their release point.
All pikeminnow moved into the Colorado River, both up- and downstream of
the Colorado/Gunnison River confluence sometime during the monitoring period.
Two pikeminnow (Codes 88 and 92) moved upstream into the 15-mile reach of the
Colorado River during the presumed spawning period in 1996; one of these fish
(Code 92) also returned to the same location in 1997. Two different fish moved
downstream in the Colorado River to Ruby/Horsethief canyons and were contacted
at two different locations, RM 143.2 (Code 82) and RM 129.6 and 132.0 (Code 96)
during the pikeminnow spawning season. Another fish (Code 88) was contacted in
Ruby Canyon at RM 134.6 and 134.5 during this same period in 1997 (Appendix;
Table K.S.). Three pikeminnow were located in the Redlands Dam plunge pool in
1996 during late-July and mid-September. Code 96 remained in the plunge pool the
longest, from mid-June to the first of July and returned in early-September and
remained there until early-November. Code 96 also returned to within 0.1 mile
downstream from the plunge pool in June 1997 and remained there for about 34
days. Interestingly, Code 96 was last contacted 0.5 mile downstream from where
it was released following radiotag implantation in mid-May 1996. Two other
pikeminnow (Codes 88 and 92) used the plunge pool sparingly. Code 92 was located
there for 2 days in early-July and Code 88 occupied the plunge pool for about 15
days from 1 September to 15 September.
1997-Tagged Fish
Capture and Release. Twelve adult Colorado pikeminnow were captured and
implanted with 29-gram LOTEV radio transmitters between 24 April and 20 June
(mean TL=688 mm; range=629-830 mm). Four of these fish were captured from WWWA,
five from Gardner and Hotspot (RM 175.0) ponds, two from the Lower Gunnison
River, and one at RM 169.3 in the Upper Colorado River. All fish except the fish
caught at RM 169.3, which was translocated and released in the Lower Gunnison
River (RM 2.9), were released following radio transmitter implantation at the
capture site (Appendix; Table J.1.).
Movement and Dispersal. Contact was established and maintained with 10 of
the 12 Colorado pikeminnow radiotagged in 1997. Unfortunately, the radiotag and
carcass of one pikeminnow implanted in 1997 (Code 78) was found in WWWA in early-
August. By late-October 1997, contact was made with nine of the eleven remaining
pikeminnow radiotagged in 1997. One pikeminnow (Code 91) was never contacted in
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