7145 ‎(2)‎

• UCREFRP Catalog Number: 7145
• Author: Inslee, T. D.
• Title: Spawning of Razorback Suckers
• USFW Year: 1981.
• Copyright Material: NO

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The number of eggs in the 9{1 tank were estimated by five people and an
average taken. It was estimated that there were 50,000 eggs in the tank. It
appeared that about 30% of the eggs were water hardened, the remainder of the
eggs either did not water harden or the yolk was broken down.
After the adult fish were removed from tank ~~1 the eggs were left in
the gravel to hatch. Samples of the gravel and rock to obtain and check eggs
gave indications that there was a heavy fungal infestation and that the water
exchange through the rocks was low. There were many dead eggs and water in
rock area was very sour. The 24 inch standpipe was replaced with a six inch
standpipe to cause a greater current over and through the rocks.
When a sample of gravel was taken five days after stocking fish, larvae
was found but later were determined to be prematurely hatched. The movements
of sampling probably caused premature hatching.
The fry started swimming up on the fifteenth day after brood fish had
been stocked in spawning tank. A total of 838 fry were harvested from tank
1i1 whereas no fry were harvested from the control tank. The low number of fry
from this tank is attributed to a suspected loss of eggs from low oxygen in
the rocks although there were no samples taken to ascertain the percentage of
good eggs.
Another trial utilizing one female and three fluid males was initiated
in a circular tank after the fish were seined from the 0.1 surface acre pond.
The female was seined from the pond, injected intermuscularly eaith 500 IU
H.C.G. and placed in the tank. The female caas reinjected 24 hours later
with the same dosage. When this female was caught 48 hours after the first
injection she released about 3,000 eggs that wexe fertilized by stripping milt
from a male and stirring with a feather. These eggs were placed in a Heath
incubator. The female was injected with 2 mg carp pituitary per pound and
returned to the tank. There were very few eggs in the circular spawning
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