7406

• UCREFRP Catalog Number: 7406
• Author: Bestgen, K. R.
• Title: Status Review of the Razorback Sucker,
• USFW Year: 1990.
• Copyright Material: NO

perhaps spawning, in a flooded pasture near Clifton, Colorado (RM
175.6)(in Osmundson and Kaeding 1989a). No accounts of abundance
are available for the Colorado River in Utah.
Reductions in distribution and abundance of razorback
suckers in the Colorado River sub-basin were evident by the early
1940's and by 1945, razorback suckers were apparently common only
in the lower Gunnison River (Wiltzius 1978). Razorback suckers
accounted for only about 1$ of all catostomids collected in 1946
by W. P. Knoch from the Colorado River at the mouth of the
Gunnison River (Hobbs and Miller 1953). By the 1950's, Beckman
(1952) considered the razorback sucker a rare species in
Colorado. Eight razorback sucker juveniles comprised less than
0.5$ of the fish collected (n=2,785) from the Colorado River near
Moab, Utah, in 1962-1964 (Taba et al. 1965). These specimens
("90-115 mm long") were the last verified razorback sucker
juveniles documented from the Colorado River.
Razorback suckers are currently rare in their historic range
in the Colorado River, and remaining individuals are scattered.
Only five razorback suckers were collected in three surveys of
fishes of Cataract Canyon, Utah, since 1979 (Persons et al. 1982,
Valdez et al. 1982a, Valdez 1990). The relatively large
concentration of razorback suckers in the Colorado River near
Grand Junction, Colorado, has declined dramatically in recent
years. From 1974 to 1976, Kidd (1977) collected 234 adult
razorback suckers; most (n=210) were from Walker Wildlife Area
gravel pit-ponds and other backwaters, near Grand Junction,
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