9396

• UCREFRP Catalog Number: 9396
• Author: Andrews, E. D., M. B. Bain, K. S. Lubinski, W. L. Minckley, J. A. Stanford, E. Wohl and R. S. Wydoski.
• Title: Highlights of a Peer review and Roundtable Discussion on the Relationship of Streamflow, Geomorphology, and Food Web Studies in Recovery of the Endangered Fishes in the Upper Colorado River Basin - Final Draft Report.
• USFW Year: 1996.
• USFW - Doc Type: Grand Junction.
• Copyright Material: NO

reviewers that the same individuals appeared on numerous studies indicating
persons were pre-selected for continuing research on the endangered fishes.

While it is impossible to cover the roundtable discussions in detail. some of
the relevant comments that were made by the peer reviewers to individual
studies are summarized in this paragraph. Recommended streamflows were
established based on fish use so that optimal streamflows required by the
endangered fish remain unknown. In addition, there appears to be uncertainty
about defining streamflows that will be sufficient to recover the fish. Test
streamflows have no controls for evaluating physical changes and biological
responses and the Program does not appear to be able to arrange for
recommended test streamflows. Also, the responses of the endangered fish may
be related to factors other than the test streamflows (e.g., habitat loss and
nonnative fish interaction). Responses of the endangered fishes to enhanced
or restored habitats would be a better criterion for evaluation than the
actual test flows. The short-term study of physical changes is not indicative
of the effects of streamflows. Studies such as sediment and channel dynamics
(Recovery Program Project 37) provide an essential first step to understanding
geomorphological effects in Upper Basin rivers.

Backwaters that have been shown to be important to the early life stages of
the endangered fishes will change in relation to discharge and channel
morphology. It is crucial to consider the hydrological and geomorphological
processes-responses upstream and downstream of reaches that are critical to
producing suitable habitat for the endangered fishes. This approach was not
apparent in the present scopes-of-work. The current method used in the food
web study may not adequately describe the energy flow through the ecosystem.
The food web study is largely limited to describing the food web that supports
native fish. The use of stable isotope analyses is effective in separation of
organic matter sources and food web components (Angradi 1994; Peterson and Fry
1987) that would provide a more comprehensive method for food web dynamics.
Little effort appears to be devoted to collecting data on the status and
trends of nonnative fishes. Yet predation and competition on the endangered
fishes during the early life stages appear to be important factors related to
the absence of or low recruitment. [NOTE: The present Recovery Program
thrust on control of nonnative fishes and changes in management of sportfishes
(i.e.. stocking procedures) were not initiated when this review was made.]
During the roundtable discussion, it became apparent to the peer reviewers
that Recovery Program participants are beginning to integrate the design and
results of the various disciplines. However. the expected results of proposed
studies and a discussion of how the results would be integrated were not
clearly documented in the scopes-of-work.

Syntheses of Available Information LackinQ. It was apparent that a lot of
information on the endangered fishes. nonnative fishes. streamflows, and
geomorphic changes has been collected through previous Program efforts.
However, this information appeared to be fragmented and disjointed. The
planning efforts for synthesizing the various Flaming Gorge studies will be
beneficial in evaluating whether the information can be fully integrated for
making decisions for future management of the Green River Subbasin. Syntheses
of the Aspinall Unit studies in the near future will serve a similar function
for the Colorado River Subbasin.

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