7990

• UCREFRP Catalog Number: 7990
• Author: Tyus, H. M.
• Title: Razorback Sucker ‎(
• USFW Year: 1997.
• Copyright Material: NO

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no significant recruitment to'any population has been documented (Tyus and Karp
1990, Minckley et al. 1991, Modde et al. 1996).
Razorback suckers have been reintroduced at several locations in the upper and lower
Colorado River basin. More than 12 million young and juvenile razorback suckers were
reintroduced into riverine habitats in Arizona and California from 1981 to 1990, but
indications are that most of these stocked fish were consumed by nonnative predatory
fishes (Marsh and Brooks 1989; Minckley et al. 1991; Mueller 1995). Some small-scale
augmentation stockings have occurred in the upper basin. Recapture results indicate
that stockings in the San Juan River have been successful in the short term (Ryden
and Pfeifer 1995).
Life History
The razorback sucker and other endemic Colorado River fishes are adapted to the
fluctuating hydrologic environment of the historic Colorado River (Minckley 1973, 1983;
Carlson and Muth 1989), with its periodically extreme flow conditions and high
turbidities. Historic riverine systems provided a wide variety of habitats including
backwaters, sloughs, oxbow lakes, and seasonally inundated floodplains (Holden and
Stalnaker 1975; Minckley 1983; Lanigan and Tyus 1989). However, some~life history
needs, including habitat requirements, and other attributes of this fish remain unknown.
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