4209

• UCREFRP Catalog Number: 4209
• Author: U.S. Fish and Wildlife Service.
• Title: Alternative Methods of Preserving and Recovering Three Endangered Colorado River Fishes, and Identification of Significant Environmental Issues.
• USFW Year: n.d.
• USFW - Doc Type: \
• Copyright Material: NO

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be at such reduced numbers (possibly extirpated) that any
existing population is unable to sustain itself. Therefore,
both the squawfish and the bonytail may be dependent upon the
implementation of active, directed management measures to even
maintain them at current levels.
E. Conservation Plan--Proposed Action
This alternative involves many, if not all, of the various
provisions discussed in the previous alternatives and will be
in addition to on-going Section 7 consultation. The major
characteristic of this alternative is that all such actions
will be done under a directed, unified design, rather than in
a piecemeal, fragmented fashion. All activities intended to
preserve and recover the fish caould be incorporated into a
directed plan of action that would increase effectiveness.
The activities proposed under a conservation plan can be
divided into the following catuborLes:
1. Research, data-gathering, and population monitoring.
Intensive field investigations would be conducted to
locate and determine current and future population numbers
for all three species. Laboratory experir~.ents into the
effects of turbidity, ~cuiperature, salinity, environmental
contaminants, and competition with nonnative species
would be conducted. field rind laboratory studies would
attempt to further refine specific habitat requirements
of the fishes. Investigation into the possible effects
of competition with other fish species, and the potential
for hybridization would expand.
2. _Research and construction of fish passage and habitat
restoration features. The capability of squawfish to
negotiate various fish passage devices, and the effectiveness
of various features designed to restore or preserve
habitat, such as instream spawning grounds and streamside
nursery areas, would be studied. Structural design and
cost estimates for construction and operation would be
developed. Certain features considered effective and
feasible would bL constructed in suitable portions of the
river system.