8123

• UCREFRP Catalog Number: 8123
• Author: Wydoski, R. S.
• Title: Coordinated Hatchery Facility Plan
• USFW Year: 1994.
• USFW - Doc Type: Need for Captive-Reared Endangered Fish and Propagation Facilities.
• Copyright Material: NO

(Ralls and Ballou 1992; Thomas 1990). The natural genetic diversity within
a population is associated with its evolutionary history and is important
for adaptation, long-term survival, and maximum production in the wild.
Protecting genetic diversity within a hatchery broodstock prevents
artificial selection, inbreeding, and genetic drift which frequently occurs
in hatchery programs (Allendorf 1993). The concept of "maximally protecting
genetic diversity" within a hatchery stock assumes that sufficient numbers
of the appropriate donor stock or population were used such that the
broodstock truly reflects the genetic characteristics of the donor
population. Proper broodstock development during the founding phase of a
propagation program is fundamental in the recovery of endangered species
because the species must possess sufficient genetic diversity to allow
survival and recruitment of the fish in altered and partially restored
environments.
It is especially important to obtain a random sample of fish that represents
i the donor population by sampling adults within and among spawning times
i throughout the spawning range of that stock. The number of wild fish
removed at any one time should be limited so that the remaining wild fish
are not adversely affected by their removal unless the species is in
immediate danger of extinction. In general, no more fish should be removed
than can be spawned at a particular time or maintained in available holding
facilities. Following successful contribution to the F, generation, wild
fish should be returned to the river reach where they were collected. If
further stocking is deemed necessary, additional wild fish can be captured
and used to supplement the genetic diversity in broodstocks.
F. Genetic Risks Associated with Captive Propagation and Stocking. Planning
recovery efforts for the endangered fishes in the Upper Colorado River Basin
will be accomplished following a logical and systematic approach (Box 3)
that will prevent potential genetic risks. A genetic risk is broadly,
defined as the sum of critical uncertainties associated with captive
propagation that may change the genetic diversity both within and among wild
stocks. Risk assessment consists of (1) estimating risk and (2) managing
risk (Lichatowich and Watson 1993). Risk assessment will be addressed in
specific stocking plans on a case-by-case basis. The potential to manage
potential genetic risks to wild stocks will be essential for a "no jeopardy
opinion" under Section 7 consultation of the Endangered Species Act.
If conducted in a scientifically sound manner, captive propagation of
endangered fish will prevent the major types of genetic risk: (1)
extinction of the species, (2) loss of genetic diversity within a species,
stock, or population; (3) loss of genetic diversity among stocks or
populations; and (4) inadvertent artificial selection that may lead to
directional succession from inbreeding or genetic swamping of wild stocks
(Busak 1990; Kapuscinski et al. 1993). The genetic processes that may be
affected by these risks and the hatchery activities that may cause the risks
are summarized in Box 4. The extinction of indigenous fish stocks can be
caused by stocking captive-reared fish but is generally preceded by the loss
of genetic diversity within and between populations.
1
1 23