APPCOR11256

• Permit No: C1996083
• IBM Index Class Name: Application Correspondence
• Doc Date: 9/3/1996
• Doc Name: MEMO FINAL BIOLOGICAL OPINION FOR BOWIE 2 MINE BOWIE COLO
• From: USFWS
• To: OSM
• Media Type: D
• Archive: No

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Based on early fish collection records, archaeological finds, and other
observations, the Colorado squawfish was once found throughout warmwater
reaches of the entire Colorado River Basin, including reaches of the upper
Colorado River and its major tributaries, the Green River and its major
tributaries, and the Gila River system in Arizona (Seethaler 1978). Colorado
squawfish were apparently never found in colder, headwater areas. Seethaler
(1978) indicates that the species was abundant in suitable habitat throughout
the entire Colorado River basin prior to the 1850's. Historically, Colorado
squawfish have been collected in the upper Colorado River as far upstream as
Parachute Creek, Colorado (Kidd 1977).
A marked decline in Colorado squawfish populations can be closely correlated
with the construction of dams and reservoirs between the 1930's and the
1960's, introduction of nonnative fishes, and removal of water from the
Colorado River system. Behnke and Benson (1983) summarized the decline of the
natural ecosystem. They pointed out that dams, impoundments, and water use
practices are probably the major reasons far drastically modified natural
river flows and channel characteristics in the Colorado River Basin. Dams on
the main stem have essentially segmented the river system, blocking Colorado
squawfish spawning migrations and drastically changing river characteristics,
especially flows and temperatures. In addition, major changes in species
composition have occurred due to the introduction of nonnative fishes, many of
which have thrived as a result of changes in the natural riverine system
(i.e., flow and temperature regimes). The decline of endemic Colorado River
fishes seems to be at least partially related to competition or other
behavioral interactions with nonnative species, which have perhaps been
exacerbated by alterations in the natural fluvial environment.
The Colorado squawfish currently occupies about 1,030 river miles in the
Colorado River system (25 percent of its original range) and is presently
found only in the Upper Basin above Glen Canyon Dam. It inhabits about
350 miles of the main stem Green River from its mouth to the mouth of the
Yampa River. Its range also extends 160 miles up the Yampa River and
104 miles up the White River, the two major tributaries of the Green River.
In the main stem Colorado River, it is currently found from Lake Powell
extending about 201 miles upstream to Palisade, Colorado (Tyus et al. 1982),
and in the lower 60 miles of the Gunnison River, a tributary to the main stem
Colorado River (Burdick pers. comm. 1995).
Critical Habitat
Critical habitat has been designated within the 100-year floodplain of the
Colorado squawfish's historical range in the following sections of the Upper
Basin (59 F.R. 13374).
Colorado. Moffat County. The Yampa River and its 100-year floodplain
from the State Highway 394 bridge in T. 6 N., R. 91 W., section 1
(6th Principal Meridian) to the confluence with the Green River in
T. 7 N., R. 103 W., section 28 (6th Principal Meridian).
Utah. Uintah. Carbon, Grand. Emery. Wayne, and San Juan Counties: and
Colorado. Moffat County. The Green River and its 100-year floodplain