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

fish in specific river reaches and collecting larval fishes downstream
from documented or suspected spawning sites. For example, in the Upper
Colorado River Basin all major tributaries have been sampled to
determine the distribution and abundance of endemic and introduced
fishes (Bestgen 1990; McAda et al. 1993; Miller et al. 1982; U.S. Fish
and Wildlife Service 1990a, 1990b, 1991). Additional work of this type
needs to be done in the other major river systems in Region 6.
3. Migration. Movement and Interchange between Stocks. Some listed and
candidate fishes are known to migrate to specific spawning areas but
return to a home area during the remainder of the year. The Colorado
squawfish migrates long distances to spawning sites and is considered
the most mobile of the endangered Colorado River fishes (Tyus 1991).
The razorback sucker exhibits moderate migrational movements (Tyus and
Karp 1991). Some humpback chub stocks (e.g., the stocks in Black Rocks
and Westwater Canyons in the Colorado River) do not migrate for spawning
(Kaeding et al. 1990) but a lower basin humpback chub stock spawns in
the Little Colorado River and uses the mainstem Colorado River in the
Grand Canyon during the remainder of the year (Kaeding and Zimmerman
1983). The greenback cutthroat trout returns to a specific spawning
stream or river. Migratory bull trout spawn and rear in tributary
streams and return to lakes to mature, while resident bull trout
complete all life stages in one stream location. Migratory bull trout
may move 100 miles or more to spawning sites (Fraley and Shepard, 1989).
Dams fragment habitat and prevent free movement of fishes. Some
geographic separation among stocks is due to such habitat alteration.
In most cases, fish are known to move between different river reaches
during the spawning season. A small amount of interchange between
stocks is a natural phenomenon that facilitates evolution. Stocks with
limited interchange will be classified separately until information is
available to justify combining them. This conservative classification
will prevent or minimize the risk of losing unique genetic attributes of
any stock that may be important in their restoration and recovery.
4. Genetic Identification and Characterization of Stocks. Genetic markers
are useful in the restoration of species. They can be used to
characterize the genetic diversity among stocks and maintain diversity
in a captive propagation program similar to the parent wild stocks
(Allendorf and Phelps 1987; Allendorf and Ryman 1987; Gauldie 1991;
Hynes et al. 1981). It is extremely important to verify inheritance
patterns and genetic characters to ensure that the markers have a
genetic basis and that they are not due to other factors such as
environment, development stage, or sample treatment (Kapuscinski and
Jacobson 1987). Diversity will be characterized by identifying genetic
markers via protein and DNA analysis. In some cases, morphometric
analyses will be used. Early detection of inadvertent hybridization due
to stocking will allow changes in the procedures that could preserve the
genetic integrity of remaining wild stocks (Hynes et al. 1981).

7