7125 ‎(2)‎

• UCREFRP Catalog Number: 7125
• Author: McAda, C. W.
• Title: Aspects of the Life History of Three Catostomids Native to the Upper Colorado River Basin.
• USFW Year: 1977.
• USFW - Doc Type: Utah State University,
• Copyright Material: YES

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communication, N. Armentrout, Bureau of Land Management, Moab, Utah],
but their abundance is not known.
During the present investigation, razorback suckers were found
to be most common, though never numerous, at two locations - the mouth
of the Yampa River (Echo Park) during early spring, and the Walter
Walker Wildlife Area near Grand Junction, Colorado, throughout the
year. Razorback suckers were occasionally found at other sampling
sites and at Echo Park during the fall (Table 1).
Razorback suckers apparently moved into the area of the confluence
of the Yampa and Green Rivers (Echo Park) in late fall (Table 2).
Although considerable sampling was done in the lower sections of the
Yampa River during summer and early fall, no razorback suckers were
collected during that period in 1975 or 1976. Razorback suckers were
never collected farther than 2.0 km upstream in the Yampa River
(Table 3). Sampling was not possible during the winter because of
ice cover and the inaccessibility of the canyon areas. Some razorback
suckers probably remained in the area over winter, although documenta-
tion is unavailable. These fish were joined the following spring
(late April) by other fish moving from the Green River into the mouth
of the Yampa River. A female razorback sucker was recaptured in the
mouth of the Yampa River after being collected two weeks earlier in
the Green River at Island Park. She had moved a distance of 26 km
(see the sections on movement and reproduction). Because she was
ripe (i.e., exuding eggs) when recaptured, it is possible to hypothe-
size the existence of a spawning migration. Further documentation
would be required before any conclusions could be established.
Razorback suckers apparently leave the mouth of the Yampa River