7875

• UCREFRP Catalog Number: 7875
• Author: Burdick, B. D., R. S. Wydoski and C. W. McAda.
• Title: Stocking Plan For Razorback Sucker In The Upper Colorado And Gunnison Rivers.
• USFW Year: 1995.
• USFW - Doc Type: \
• Copyright Material: NO

selection of stocking areas, and the protocol and criteria to investigate the
relation between size at stocking and survival and time of stocking. The plan
also outlined research efforts and general procedures to monitor stocked fish
and evaluate the stocking program. Although the plan is comprehensive, it did
not identify the number of smaller-sized razorback sucker that would be needed
to evaluate the relation of survival to size at release, and the number of
adult fish needed per river reach to achieve recovery.
In the Gunnison River, the razorback sucker are thought to be extirpated,
and the present population in the Colorado River is so low that they are
considered functionally extinct. So few adult riverine fish remain in the
wild that it is unlikely that a population can be restored through natural
reproduction. As a consequence, the Biology Committee has placed a high
priority on stabilizing the middle Green River stock and reestablishing
razorback sucker in the Upper Colorado and Gunnison rivers.
As part of genetics conservation management, the Genetics Management
Guidelines (Williamson and Wydoski 1994) require that a stocking plan be
deeloped to provide the justification and rationale for specific actions
regarding the stocking of captive-reared endangered fish in the Upper Colorado
River Basin including details such as species, size of fish, timing of
release, location of release, genetic risks, and a description of how
evaluation of the stocking will be made. The purpose of this document is to
provide a razorback sucker stocking plan for the Upper Colorado and Gunnison
rivers for 1996 through 2000 that will supplement Burdick (1992).
III. RELATIONSHIP TO RECOVERY PROGRAM
One of the underlying missions and philosophies of the Recovery
Implementation Program for genetics management of endangered fishes of the
Upper Colorado River Basin is that the genetic integrity is maintained and
managed to prevent irreversible losses of genetic diversity. Genetics
management of Colorado River basin endangered fishes is an integral part of
the Program that involves native fish stocking. Augmenting or restoring
populations by stocking endangered fishes has been identified as one of the
/ five elements for recovery of endangered fishes in the upper basin. It has
also been identified as an activity for the Colorado River mainstem and
Gunnison River in the Recovery Implementation Program's Recovery Action Plan
(RIPRAP; USFWS 1995a). Developing a stocking plan for razorback sucker and
seeking acceptance from the Recovery Program is an item in the RIPRAP.
IV. STOCKING PLAN
This stocking plan outlines an expanded experimental field study to
determine the survival and performance of stocked captive-reared razorback
sucker. The study will evaluate re-introduction stocking of razorback sucker
as a management strategy to develop self-sustaining populations in the Upper
Colorado and Gunnison rivers.
The intent is to stock all surviving captive-reared razorback suckers into
the Gunnison and Upper Colorado rivers if the fish meet the "Genetics