7025

• UCREFRP Catalog Number: 7025
• Author: Hawkins, J. A. and T. P. Nesler.
• Title: Nonnative Fishes in the Upper Colorado River Basin
• USFW Year: 1991.
• USFW - Doc Type: An Issue Paper.
• Copyright Material: YES

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which nonnative species affect which endangered species and how. Recommendations 7-
10 provide further guidance regarding research activities that would document negative
impacts to recruitment, negative competitive interactions, and the utility of flow-related
management, habitat enhancement, or fish control efforts in reducing the abundance and
effects of introduced fishes or enhancing the survival of native fishes. Recommendations
11-12 encourage better research planning and design based on previous research results.

Currently, research is ongoing that addresses some of the concerns and
recommendations above. Results from these studies will provide further guidance of a
more specific nature regarding problem species, interactions with native fishes, and
effects of environmental manipulations. Decisions concerning future research needs or
field management activities can be refined when these studies are completed.

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Until research documentation provides the necessary direction, specific
management activities targeted at negatively affecting introduced fish species should be
selected carefully. Negative management activities directed at introduced fish species
with little sportfish value can probably proceed without arousing opposition. In the
meantime, agencies can seek to minimize suspected negative impacts from nonnative
fishes by more conservative management of certain predaceous gamefish species in
select, or restricted aquatic habitat. This is the essence of management recommendations
1-2. Agencies can also manage for identifying and ~educing incidental harvest of
endangered and native fishes via angling by continuing to monitor river reaches via creel
survey, protecting endangered fishes and select river reaches vulnerable to angling
pressure, and continuing public relations and education efforts aimed at promoting
identification and release of endangered and native fishes. This is the intent of
management recommendations 3-5.

Recommendations 6-8 suggest means of improving management for nongame and
native fish fauna via better communication between nongame and gamefish interests,
review of present stocking programs and goals, and expanded regulatory procedures for
preventing undesirable introductions of non-native fish species. Reintroduction or
augmentation of native endangered fishes are potential management options applicable
in the field. Research results have suggested this approach can be severely affected by
the presence of predaceous fish species in the receiving waters. Recommendation 9
suggests a protocol and procedure for reintroduction or augmentation in riverine habitat
affected by introduced predaceous fishes.

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