8232

• UCREFRP Catalog Number: 8232
• Author: Burdick, B. D.
• Title: Evaluation of Fish Passage at the Grand Valley Irrigation Company Diversion Dam on the Colorado River Near Palisade, Colorado.
• USFW Year: 1999.
• USFW - Doc Type: CAP-17,
• Copyright Material: NO

flannelmouth sucker) were all marked by clipping the left pelvic fin.
All native fish implanted with PIT tags exceeded 150 mm. A11 nonnative
fish captured that were tagged with Floy® tags were at least 200 mm. All fish
that were fin clipped were at least 100 mm. Oniy fish captured downstream of the
GVIC Diversion were marked. No fish were marked after 28 August nor upstream of
the GVIC Diversion Dam during this study.
Centrarchids (largemouth bass and smallmouth bass) and ictalurids (channel
catfish) that were captured up- and downstream of the GVIC Diversion Dam as "by-
catch" were removed and disposed. Mountain whitefish were not marked or tagged
and were released alive. All other nonnative fishes (carp, white sucker, and
sucker hybrids) except salmonids collected upstream of the diversion dam were
removed.
Sampling upstream of the diversion dam with electrofishing attempting to
recapture marked fish that had moved from the downstream reach was conducted once
prior to spring runoff and 10 times during post-runoff river stage. Sampling
downstream of the diversion dam to mark and tag fish also resulted in recapturing
some of the fish previously marked and tagged. Prior to- and following runoff,
eight days were dedicated to each sampling effort downstream of the diversion
dam.
Electrofishing was conducted either from an outboard-powered, 16-foot,
aluminum jon boat or from a 14-foot, oar-powered rubber raft. The jon boat was
equipped with a 5-kilowatt Honda generator and a Coffelt° VUP-15 voltage pulsator
to adjust the voltage and amperage transmitted to the water. The rubber raft was
used during low-flow conditions and was equipped with a 5-kilowatt Vanguard°
generator and a Smith-Roots 5.0 GPP voltage pulsator. Investigators used direct
current and tried not to exceed 300 volts or 12 amps to minimize injury to fish,
while maximizing electrofishing effectiveness.
The second method incorporated telemetry to follow movements of sub-adult
and adult Colorado pikeminnow captured in the 15-mile reach that had been
implanted with LOTEK~-coded transmitters (model no. MCFT-7A). The transmitter
weighed 29.0 g (air weight), was 83-mm long with a 16-mm circumference, and had
a theoretical life of about 360 days. It was surgically implanted in the body
cavity of adult Colorado pikeminnow using techniques outlined by Hart and
Summerfelt (1975) and Tyus (1984). The transmitter had an external antennae,
that consisted of a plastic-coated metal cable, that was approximately 16-inches
long, and. that extended outside the fish which required slight modification in
surgical technique (Ross 1982).
Lotek~ SRX 400 telemetry receivers were used to monitor movements of
transmitter-tagged fish. One fixed, land-based tracking station was deployed in
mid-April 1998 at the GVIC Diversion Dam. This station consisted of a data-
logging receiver and two, four-filament Yagi antennae arrays that constantly
monitored and recorded signals from tagged Colorado pikeminnow. One antennae
array constantly checked for fish immediately downstream of the diversion dam and
another checked for fish passing through the newly-constructed notch. Because
the land-based, data-logging receiver was powered by a photovoltaic panel
equipped with a solar battery that stored electricity, the data logger was
6