8169a

• UCREFRP Catalog Number: 8169a
• Author: Brookshire, D. S., M. McKee and G. Watts.
• Title: Draft Economic Analysis of Proposed Critical Habitat Designation in the Colorado River Basin for the Razorback Sucker, Humpback Chub, Colorado Squawfish, and Bonytail.
• USFW Year: 1993.
• USFW - Doc Type: \
• Copyright Material: NO

Of the historical range of humpback chub, 26 percent is proposed for designation as critical
habitat.
d. Bonytail
The bonytail is the rarest native fish in the Colorado River. Formerly reported as widespread
and abundant in mainstem rivers, its populations have been greatly reduced. Of this once
abundant species, only a small number of old adult fish (i.e., ages 40 years or more) still exist
in Lake Mohave and perhaps other Lower Basin reservoirs. The fishes were once common in
Lake Mohave.
USFWS is proposing 6 reaches of the Colorado River system (Figure I-2-4) for designation as
critical habitat for the bonytail. In the Upper Basin, critical habitat is being proposed for
portions of the Green, Yampa, and Colorado rivers. A reach of the Colorado River is being
proposed in the Lower Basin. Of the historical range of bonytail, 15 percent is proposed for
designation as critical habitat.

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Figure I-2-4. Map of Proposed Critical Iiahitat for the Bonytail.
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