WSP00173

• File Number: 8240.200.10.A
• Description: UCRBRIP Habitat Restoration
• Basin: Colorado Mainstem
• Date: 10/8/1997
• Author: UCRBRIP
• Title: Final Habitat Restoration Program FY 1998 Work Plan Part 2
• Water Supply Pro - Doc Type: Publication

Assessment of relative viabi1.it:y of F2 progeny and backcrosses

Relative viability of hybrid offspring to pure parentals will be monitored
intensively during the first four months and routinely during subsequent
months for each study year. We have divided the analysis into three life-
stages: fertilized egg stage, larval stage, and juvenile stage.

Fertilized egg stage:
For each of the 72 family lots the following measurements will be made:

Hatching percent
Mortality rate
Percent to free-swimming stage
Percent deformed individuals

Each of the parameters will be measured by examining the lots on a daily basis
(more than one observation will be made at hatching).

Larval staqe:

Variables to be measured:

Growth rate
Mortality rate

These variables will be measured on a weekly basis during the four month
period.

Juvenile staqe:

Bilateral asymmetry will be measured once individual fish are> 70 rom in
length.

Lipid content will also be measured as a condition indicator if fish are
available. Fish must be sacrificed to measure lipid content.

Other variables to be measured:

Growth rate
Mortality rate
Age to first reproduction
Percent deformed individuals
Sex ratio (when possible)

These variables will be measured once every 2 months to quantify growth rate
(length and weight) and survivorship.

VII. Task Description and Schedule:

PHASE I: F~ VIABILITY

FY ~998

Task ~.

Obtain Gila adults.

Task 2.

'Perform Gila crosses.

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