3301

• UCREFRP Catalog Number: 3301
• Author: Papoulias, D.
• Title: Effect of Food Availability on Growth and Mortality of Larval Razorback Sucker,
• USFW Year: n.d.
• Copyright Material: NO

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arranged in rows in raceways. Jars were placed in series, (not
randomly), with position effects controlled by a constant
temperature water bath and providing uniform lighting.
Continuous water flow at approximately 100 ml/min and constant
volume were provided by 2.54-cm pvc pipes perforated above each
aar. Jars were tiltad to facilitate outflow and screened with
fine mesh to prevent escape of larval fish and live food.
On 11 February 1985, adult male and female wild-caught (Lake
Mohave) razorback suckers were infected with human chorionic
gonadotropin. Three days later, fish were stripped and
fertilized eggs incubated at 210C in Heath trays (R. Hammond,
pers. comm.). Hatching occurred from 19 through 21 February and
swim-up on 23 February. On 25 February, 10 mm total length (TL)
larvae were stocked at 10 individuals per ,far. Experiments were
continued for 50 days, until 16 April, at a constant temperature
of 180C.
Fish selected for feeding received newly-hatched brine
shrimp (Artemis saline) nauplii. San Francisco BayR brand eggs
were incubated in aerated gallon bars at 27-28oC for 36 hours, at
which time most had hatched. Jars were agitated and allowed to
sit for 1/2 hour, during which time unhatched eggs floated to the
surface and nauplii accumulated near bottom. The latter were
siphoned to a glass beaker. Density estimates were by 5 counts
in a Sedgewick-rafter cell on 1 ml aliquots. Appropriate amounts
were then removed and prepared by dilution for various levels of
feeding. Fish were fed 3 times a day at 8-hour intervals. Jars