7890

• UCREFRP Catalog Number: 7890
• Author: U.S. Fish and Wildlife Service.
• Title: Region 6, Fish and Wildlife Service Guidelines Directing Captive Propagation Of Listed And Candidate Fish.
• USFW Year: 1996.
• USFW - Doc Type: \
• Copyright Material: NO

propagation program for imperiled species must consider the genetic implications of all
activities. It must be the guiding concept for the entire planning process.
BROODSTOCKS
A necessary element of native fish stocking includes the development of genetically sound
broodstocks. Broodstock can be derived from two different sources: 1) Wild fish caught by
commercial, sport, tribal, federal or state employees; and 2) Hatchery-reared fish which are
progeny of wild-caught fish. Propagation or reproduction is central to achieving restoration
or recovery goals. Hatchery propagation must be an identified restoration or recovery
activity--a tool to use in initiating and sustaining propagation in the wild and maintaining rare
gene pools in captivity. All. captive broodstocks should be genetically representative of each
selected wild population, and each population should be held at a minimum of two separate
facilities to guard against a catastrophic loss, conserve unique genetic material, and preserve
options for future activities.
If sufficient adult fish are available and removal from the wild will not jeopardize the genetic
characteristics of the founder stock, a minimum of 50 adults (25 males and 25 females)
should be used to develop broodstocks since the likelihood of inbreeding will be minimized.
Broodstocks will be developed through paired matings that produce pedigreed family lots.
An inbreeding rate of 1 per cent was estimated for an effective population size of 50 fish that
• is considered to be acceptable for maintaining the genetic diversity of wild fish stocks.
When stocks are low, a minimum breeding strategy using a 5 X 5 di-allele cross should be
used to develop broodstocks. A 5 X 5 strategy has an effective population size of 10 fish,
and an estimated inbreeding rate of 5 per cent. In the event that 5 males and 5 females are
not available, a factorial mating design will be used to capture the genetic contribution from
all fish of the least numerous sex. Additional wild adults should be used to supplement the
broodstock that are developed from a 5 X 5 or factorial cross, when they become available,
to increase the effective population size and reduce the estimated inbreeding rate.
Mating crosses of hatchery-reared broodstock should generally be done using individuals
from different year classes. This crossing will convert genetic differences between the year
classes, which undoubtedly exist because of the relatively small number of fish spawned each
year, into genetic variation within the broodstock. Matings should also be random to avoid
making genetic changes by selection. Continuous genetic evaluation and monitoring of
captive broodstocks should be conducted and is a central feature of a well-designed
broodstock program (Hard et al. 1992). The rearing regime for future broodstock should
parallel that of any production fish, except there should be no mixing of these two uses of
fish.
The broodstock program will be guided be the following documents: 1) Genetic
Management Guidelines For Listed and Candidate Fish Species In Region 6, 2) Fish
• Broodstock Policy, 3) Inland Salmonid Broodstock Management Handbook (712 FW 1), and
4) Other broodstock guidance material found in published documents, Service, State, and