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

EXECUTIVE SUMMARY
The Redlands Dam passageway, constructed on the Gunnison River, a major
tributary of the Colorado River, near Grand Junction, Colorado, was completed in
1996. The first of its kind in the Upper Colorado River Basin, its specific
purpose was to provide upstream passage for two Federally listed fishes, the
Colorado pikeminnow and razorback sucker. It was also designed for selective
passage. That is, it was to preclude upstream movement of nonnative fish.
The purposes of this investigation were to 1) evaluate whether sub-adult
and adult Colorado pikeminnow would use the fish passageway at Redlands Dam and
2) monitor movements and distribution of Colorado pikeminnow that pass through
the fish passageway.
The 5-year evaluation relied on three separate investigative techniques.
Fish were collected in the trap at the Redlands passageway to obtain data on the
number of large-bodied fish using the passageway, species and numbers per
species, and seasonal distribution by species. Telemetry was used to determine
movement patterns and distribution of sub-adult and adult Colorado pikeminnow in
the passageway and in the Redlands Dam plunge pool, in the 2.3-mile reach
downstream of the diversion dam, and those that passed through the passageway and
were released immediately upstream of the dam. Electrofishing was used to
determine if any of the Colorado pikeminnow that had passed through the fish
passageway associated with other pikeminnow at spawning site(s) in the Gunnison
River upstream of the diversion dam.
Telemetry incorporated a digitally encoded system to follow movements of
sub-adult and adult Colorado pikeminnow, captured in the fish trap, from the 15-
and 18-mile reaches of the Upper Colorado River, and pikeminnow captured in the
Lower Gunnison River that had been translocated upstream of the Redlands Dam.
Ground surveillance was used to monitor the movements of radio-tagged pikeminnow
from a boat and from three fixed, land-based tracking stations equipped with data
loggers. One station was located at the diversion dam and the other two were
strategically located up- and downstream from the dam. The ground stations
constantly monitored and automatically recorded signals from transmitter-tagged
fish.
Summary results from this research were many. The only listed fish
collected in the passageway trap was the Colorado pikeminnow. Forty-three
different sub-adult and adult Colorado pikeminnow ascended the Redlands
passageway from 1996 through 2000. Seven different pikeminnow ascended the
passageway twice. One of these fish ascended the passageway three different
times. The greatest number of pikeminnow were collected in 1998 (23) followed
by 1997 (18). The number of pikeminnow declined to 5 in 1999 and to 4 in 2000.
Pikeminnow used the passageway almost exclusively in July and August over the
five-year evaluation: 35 (69X) in August and 15 (29X) in July; one pikeminnow
used the passageway in early-September 1999. The migration of pikeminnow through
the passageway was during post-runoff which was associated with the period
immediately following spawning.
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