8097

• UCREFRP Catalog Number: 8097
• Author: American Fisheries Society.
• Title: Proceedings of the 18th Annual Meeting, Colorado - Wyoming Chapter, American Fisheries Society.
• USFW Year: 1983.
• USFW - Doc Type: March 2-3, 1983.
• Copyright Material: NO

bass spawned within 24 hrs after introduction into the spawning pond. Fry
hatched within 8-10 days after broodfish stocking, and swim-up fry were
present 3 days later.
After 3-4 additional weeks, spawning ponds were drained and fry trans-
ferred to rearing ponds at 22,000/ha. Due to limited space, however, some
fry were reared in spawning ponds after brood stock were removed by sein-
ing. In both cases the ponds were fertilized with organic and inorganic
products to promote plankton production. Bass fry remained in the ponds
until they attained 50 mm in length or had depleted plankton levels, at
which time ponds were drained and fingerlings sorted into uniform size
groups. The fingerlings were then placed into cages suspended within a pro-
duction pond where artificial diet training took place. Cages were constructed
of 25 mm x 51 mm pine ~ith 3.2 rom mesh wire screen sides and had a volume
of approximately .93 m. From two to four cages were used each year with
a maximum of 12,000-15,000 fingerlings per cage.
A ground carp flesh slurry was presented to the fingerlings up to 10
times daily for 8 days. During part of this period, small BioDiet pellets
were added to the carp mixture in increasing proportions until the termin-
al diet consisted of 100% BioDiet. This sequence was similar to that used
by Willis and Flickinger (1981) for largemouth bass training. When the bass
consistently took the artificial diet, training was discontinued. This usu-
ally took 11 to 14 days after which the fingerlings were moved to small
(.11 ha) training ponds where BioDiet pellets were fed. Those fish which
did not successfully train to artificial food were either retrained, if pos-
sible, or stocked out. Fingerlings were kept in training ponds for about
1 month and were then moved to overwinter ponds. BioDiet was fed until fall
at which time minnows and other forage were added. In the spring, when water
temperatures exceeded 130C, BioDiet was again fed along with minnows remaining
in the ponds. Bass were moved to raceways in early June at lengths of 120-130
mm to be marked before stocking.
Equipment used for spray marking consisted of an air compressor, spray
gun, a 120 cm x 24 cm spraying trough with nylon mesh bottom, and colored
pigment. The spray gun reservoir was filled with pigment and the pressure
adjusted by spraying directly onto a spring balance at a distance of 230 rom
and changing air flow until a constant reading of 460-500 g was achieved.
Approximately 20 bass were netted from the raceway, placed in the trough
and sprayed until they has a "painted" look. Fish were then dipped into
a salt solution for 30 seconds, and returned to the raceway.
Bass sloughed off most of the pigment within 24 hrs but numerous
particles remained imbedded under the scales. Two days were allowed before
fish were transported. At the end of the two day period mortality was usu-
ally less than 5%. Approximately 100 fish in 1981 and 1982 were kept at
the hatchery as a control to determine mark retention. Bass were hauled to
the reservoir in hatchery trucks in which Furacin and salt were added to
minimize stress. Bass fry were distributed to most areas of the reservoir
by boat. Bass stocking was to be evaluated at a stocking rate of 50 per
"habitat-acre." Habitat-acre was defined for reservoirs greater than 100
acres as:

H.A.

([actual acres - 100] x .20) + 100

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