7203

• UCREFRP Catalog Number: 7203
• Author: Osmundson, D. B. and L. R. Kaeding.
• Title: Colorado Squawfish and Razorback Sucker Grow-Out Pond Studies as Part of Conservation Measures for the Green Mountain and Ruedi Reservoir Water Sales
• USFW Year: 1989.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

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During 1986-1988, we conducted additional studies to further develop
techniques for rearing young Colorado squawfish and razorback sucker in
gravel-pit ponds. In addition, attempts were made to spawn locally caught
Colorado squawfish so that progeny reared in the ponds would be of the
same genotype as the local, wild subpopulation. This report summarizes
our results and provides recommendations for future fish-rearing activi-
ties.
METHODS
In May 1986, two rearing ponds were selected and leased from local land-
owners. These former gravel pits are located between Grand Junction and
Fruita, Colorado. Fish Chalet ?ond is 1.62 ha and West Pond is 1.34 ha;
both have a maximum depth of 3.2 m. West Pond was devoid of fish, whereas
Fish Chalet, a pond used during Osmundson's (1987) 1983-85 studies, con-
tained common carp (Cyprinus carpio) and channel catfish. To eliminate
predation by non-native fishes as a potential mortality factor, Fish
Chalet Pond was treated with the toxicant rotenone to remove catfish
before squawfish were stocked. Fathead minnow (Pimephales promelas)
populations, a forage base for squawfish, were then established by stock-
ing 175 locally-captured, adult fatheads in each pond. To increase pro-
ductivity, ponds were fertilized on two occasions with Triple Super Phos-
phorus (45% available phosphoric acid) at a rate of 2.3 kg/acre ft.
Electrofishing and trammel-netting were used to capture seven adult Colo-
rado squawfish for use as broodstock. These fish were collected during
12-23 May 1986 from the Colorado River between Grand Junction and Clifton,
Colorado (RMI 165.5-175.1) and transferred to a holding pond at the Tiara
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