7990

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

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almost exclusively on benthic larval Chironomidae and early instar Ephemeroptera
(Maddux et al. 1987; R.T. Muth, Colorado State University, pers. comm., 1992).
As razorback sucker larvae grow, the mouth metamorphoses to become inferior, and
the fish begins feeding more on benthic foods. Unfortunately, few details are known
about the diet of juvenile razorback suckers because fish of this age are rarely
encountered. The only study known reports "algae and bottom ooze" from the
digestive tract contents of eight juvenile (90-115 mm) razorback suckers taken from a
Colorado River backwater (Taba et al. 1965).
The diet of adult razorback suckers taken from riverine habitat consisted chiefly of
immature Ephemeroptera, Trichoptera, and Chironomidae, along with algae, detritus,
and inorganic material (Jonez and Sumner 1954, Banks 1964, Vanicek 1967). The diet
was of benthic origin, but may have been taken from drift. Diets of reservoir-dwelling
adults were dominated by planktonic crustaceans (Cladocera), but also contained some
algae and detritus (Minckley 1973; Marsh 1987).
Larval and juvenile razorbacks in hatchery ponds at Dexter, New Mexico (Hamman
1987) and Vernal, Utah (Lanigan and Tyus 1988) have been reared successfully on
natural foods (i.e., phytoplankton and small zooplankton). They also have.been reared
in aquaria using brine shrimp (Artemis sp.; Papoulias and Minckley 1990). In addition,
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