9585

• UCREFRP Catalog Number: 9585
• Author: U.S. Fish and Wildlife Service.
• Title: Inland Salmonid Broodstock Handbook.
• USFW Year: n.d.
• Copyright Material: NO

For this reason, future brood eggs that have been
set aside from paired coatings should be incubated
- separately based on the date the eggs were taken.
Such a protocol allows adjustments in egg numbers to
be made at a later date, insuring that the
.contribution from a given spawning take is relative
to the number of females actually spawned on that
date. At certain facilities, eggs from early takes
may actually begin to hatch before the entire
population has been spawned. In these situations,
"best guess" extrapolations based. on hatchery
records should be used to estimate the relative egg
contribution"from a given egg take.
For Eusmple:
Spawn Date -May 1 May 7 May 14 May 21 May 28
Females Ripe 50 250 400_ 250 50
Females used
for future
brood eggs 25 50 100 50 25
t©tal number should be a minimum of 250
Total number of females ripe on the days brood eggs were taken
1000 (50+250+-400+250+50)
May 1 = 50 females or 5%
May 7 = 250 females of 25%
May 14 400 females or 40%
May 21 = 250 females or 25%
May 28 = 50 females or 5%
If 5000 eggs are needed for future brood 5% would come from the
paired coatings on May 1(250), 25% from the coatings on May 7
(1250) , 40% from the coatings on May 14 (2000) , 25% from the
coatings on May 21 (1250) , and 5% would come from the paired
coatings on May 28 (250). This regimen will help to insure
genetic variation while maintaining time of spawning.
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