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

Since the goal of restoration and recovery is to develop self-sustaining
populations or stocks, strategy 1 has been used in the recovery of the
Colorado squawfish, humpback chub, Kendall Warm Springs dace, and Neosho
madtom. Strategy 2 is being used for recovery of the razorback sucker,
bonytail, pallid sturgeon, greenback and westslope cutthroat trout, and bull
trout. Strategy 3 may be used as a last resort to maintain a species in the
wild. However, listed and candidate fish stocks that are in jeopardy of
extinction could be maintained in refuges as broodstocks that are
genetically managed until the limiting factors in their natural environment
can be eliminated or reduced.
III. IDENTIFICATION AND CHARACTERIZATION
OF LISTED AND CANDIDATE FISH STOCKS
and
DETERNINING THEIR STATUS AND TREND
Individuals of natural animal populations are rarely distributed randomly and
their distributions may range from continuous to clumped (Barker 1989). The
philosophy and goals of genetic management are based on the recognition that
stocks or local self-sustaining populations must be considered the operational
unit in their restoration and recovery.
A. Criteria for Identification and Characterization of Fish Stocks. A stock is
defined as a randomly breeding group of individuals that has spatial,
temporal, or behavioral integrity from other randomly breeding groups of
that same species (Kutkuhn 1981). This stock definition applies to multiple
stocks within an individual river or a single stock comprising fish from
various rivers within a basin (Philipp et al. 1993). The biological
uniqueness resulting from isolation or geographic separation is an
evolutionary one and such stocks have been referred to as "evolutionary
significant units" (Dizon et al. 1992).
Criteria considered to identify and characterize fish stocks include
distribution and abundance, spawning, migration, and genetic information
(Dizon et al. 1992, Ihssen et al. 1981). The criteria used to identify and
characterize listed and candidate fish stocks will be:
1. Geographic Distribution and Abundance. The basic criteria used to
categorize fish stocks are distribution and abundance. Some disjunct
stocks are geographically separated from others and do not appear to
exhibit interchange between them. For example, the humpback chub is
found in relatively small concentrations that are widely separated and
confined to short reaches of deep canyon areas (Valdez and Clemmer 1982;
Tyus and Karp 1989; Tyus and Karp 1991).
2. Identified or Suspected Spawning Sites. Spawning sites and spawning
time must be determined. This will be accomplished by collecting ripe
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