7715

• UCREFRP Catalog Number: 7715
• Author: U.S. Fish and Wildlife Service, C. R. F. R. T.
• Title: Bonytail Chub Recovery Plan.
• USFW Year: 1990.
• USFW - Doc Type: \
• Copyright Material: NO

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key characteristics which separate them will be identified. The group of
experts also will attempt to identify any recent changes in the genetic and/or
morphological characteristics of the Gila complex and to relate these changes
to any environmental modifications. The initial timeframe for completion of
the work is an estimated 4 years.

Distribution and Abundance
Historic Distribution

The original records of bony tail chub were from the Colorado and Gila Rivers
(Baird and Girard 1853; Jordan 1891; Jordan and Evermann 1896) (Figure 1).
Captures in the Green River indicate bony tail chub were present in southern
Wyoming in the reach where Flaming Gorge Reservoir now is located (Bosley
1960; Smith et al. 1979), in Dinosaur National Mnnllment in Colorado and Utah
(Binns et al. 1963; Vanicek and Kramer 1969; Vanicek et al. 1970), Desolation
and Gra Can on in Utah (Holden 1978), and the lower Green River in Utah
Jordan 1891; Holden and Stalnaker 1975). In the ~olorado River mn;nstem,
they were collected from near Grand Junction, Colorado, to the mouth of the
Colorado River at the Gulf of California (Ellis 1914; Smith et al. 1979).
Major tributaries of the Colorado River where bony tail chub were recorded
included the Gila (Kirsch 1888), Salt (Evermann and Rutter 1895), and Verde
Rivers in Arizona (Smith et al. 1979); the San Juan River (Cope and Yarrow
1875); and the Gunnison R;v~r (Smith et al. 1979). The species also entered
the Salton Sea basin in California when that area received Colorado River
inflow during 1905-07, but disappeared when salinity became intolerable
(Walker et al. 1961).

The bony tail chub was reported abundant in some locations of the Colorado
River. drainage in the late 1800's (Jordan and Evermann 1896). Jordan (1891)
seined five specimens from the Green River at Green River, Ut~ and Kirsch
(1888) cited an expedition on the Gila River at Ft. Thomas, Arizona, which
noted that the fish "took the hook freely." A number of other reports also
indicated it was common to abundant during this period (Cope and Yarrow 1875;
Gilbert and Scofield 1898; Chamberlain 1904). However, some of these and
later reports may be questionable due to possible use of the term "bony tail"
for other Gila species, particularly the roundtail chub (~. robusta) in the
Upper Basin.

There were few reports of bony tail chub for the Upper Basin in the first half
of the 20th century. The species declined in the Lower Colorado River Basin
(Lower Basin).during this time, disappearing from the Salt and upper Gila
rivers before 1926. Miller (1961) reported that, by 1940-1942, bony tail chub
were rare in the Colorado and Gila rivers near Yuma, Arizona, and absent by
1950. Soon after closure of Glen Canyon Dam in 1962, bony tail chubs were
reported in Lake Powell (Kent Miller and Dale Hepworth, Utah Division of
Wildlife, pers. comm.) and downstream of the dam to Lee's Ferry (Arizona State
University museum records 1963-1965). "Older" fishermen reported that
bony tail chub were caught in the upoer Green Ri\/er during the 1940's and
1950's. However, the last known riverine area where bony tail chub were common
was the Green River in Dinosaur N tio , where Vanicek (1967) and
Holden and Stalnaker (1970) ~ollected 91 s ecimens durin 1962-1966.

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