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

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laboratory experiments are needed in the recovery Program. Endangered fish
and hatchery facility needs will be reviewed annually by the Biology Committee
so that adjustments can be made to accommodate critical immediate Program
requirements and to effectively plan for short-term and long-term needs.
Identification Characterization Status and Trends of Endangered Fish Stocks
in the Upper Colorado River Basin

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Four presumptive stocks of razorback suckers, five stocks of humpback
chub, and five stocks of Colorado squawfish in the Upper Colorado River
Basin were identified based on suspected or identified spawning sites
or geographical separation of the stocks. The assignment of presumptive
stocks for the upper basin was conservative to ensure retaining the
genetic diversity of all possible stocks because the results of the
ongoing genetics and systematics studies were not available to be
considered in this analysis.
Status and trends of presumptive stocks were reviewed for endangered fish
in the Upper Colorado River Basin. Species priorities were assigned on
the basis of stock status and trends: razorback sucker - 1; bonytail - 2;
humpback chub - 3; and Colorado squawfish - 4. Priority "1" indicates
the highest priority and "4" the lowest priority. The assignment of
priority 1 to the razorback sucker was based on the recovery potential of
upper basin stocks. Assignment of priority 2 to the bonytail was based
on the fact that only occasional captures of this species are made
infrequently in the upper basin so the potential for capturing sufficient
fish for broodstock development in the upper basin is remote. Broodstock
development for restoration stocking efforts of this species will depend
upon captive fish of Lake Mohave stock.
The razorback sucker was identified as the species that is most likely to
become extirpated in the Upper Colorado River Basin because of the declining
trend in adults and lack of recruitment. Immediate development of razorback
sucker broodstocks can be viewed as a "life insurance policy to prevent
extinction of a species". These fish would be propagated to meet Program
needs for broodstock development, research studies, information and education
programs, and stocking (experimental, augmentation, and restoration).
The bonytail is close to extirpation in the upper basin and wild adults are
captured so infrequently that development of a broodstock of upper basin
bonytails is not likely. However, Program protocol has been developed to
bring bonytails captured in the upper basin into captivity for broodstock
development. Development of a broodstock and restoration stocking of this
species in the upper basin will probably have to be made from Lake Mohave
stock that is maintained at the Dexter National Fish Hatchery and Fish
Technology Center, New Mexico. This species can readily hybridize with other
Gila (Haman 1981b) and restoration stocking in the upper basin would be
premature, until the Gila genetics and systematics studies are completed as an
interim report in 1995 and a final report in 1997.
Humpback chub stocks are considered low in number but considered to be stable
in localized reaches of the upper basin. The potential for catastrophic loss
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