9547

• UCREFRP Catalog Number: 9547
• Author: Tyus, H. M. and J. F. S. III.
• Title: An Evaluation of Recovery Needs for Endangered Fishes in the Upper Colorado River, with Recommendations for Future Recovery Actions - Final Report.
• USFW Year: 1999.
• USFW - Doc Type: Glenwood Springs, CO.
• Copyright Material: NO

squawFsh) also appears to be relatively stable, a~hough strong year classes are
infrequent and populations in the UCR are small.
~ Clearly there is a need to maintain or increase the size of extant populations, and to
accomplish this management actions have focused typically on improving physical
habitat conditions. In particular, attention has been devoted to establishing a flow
regime that will benefit adult fish. A serious shortcoming in these management actions
has been the lack of emphasis on biotic factors, especially introduced nonnative fishes.
To date, no successful program has been developed to control or reduce the
~ abundance of nonnative fishes, and it is doubtful if recovery will be successful until that
happens.
Addressing biotic factors alone is no guarantee of successful recovery, however. In
general, recovery will require a more comprehensive view of limiting factors for a given
~ species, which will vary spatially and temporally. Moreover, biotic (biological) and
abiotic (physical and chemical) limiting factors may operate simultaneously. Thus,
successful application of management action at the local level will require a view of
limiting factors that considers all life history stages and the hab~at used by each stage.
In addition, managers must determine when action deemed necessary for recovery may
~ not be sufficien#. For example, creating and maintaining optimal physical habitat is a
condition necessary for recovery, but it may not be sufficient where nonnative predators
have the capacity to eliminate recruitment.
This-study emphasizes that a more holistic approach is needed in the recovery
~, program, and recommends development and formal adoption of a multispecies or
ecosystem recovery plan. Such a plan would encompass all fishes in the big river
community throughout their range as the best mechanism for implementing a broader
and more comprehensive perspective on recovery of the four listed fishes. By
incorporating geographic priorities, such a plan could guide local recovery efforts, and
aid communication and coordination with recovery efforts in other locations as well.
~ Such an approach also would aid in monitoring the status of other species at risk and
insure that other species would not need to be listed in the future.
The following additional conclusions and recovery recommendations address present
recovery efforts for each specific initiative of the RIP, and have been drawn from the
~ review and synthesis of existing information:
Instream Flows:
The need for suitable instream flows for all life stages of the endangered fishes has
~ long been recognized, but more effort is needed to understand how instream flows
affect the fishes, and how adverse effects can be minimized or avoided.

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