7612

• UCREFRP Catalog Number: 7612
• Author: Roberts, B. and M. Moretti.
• Title: Final Fisheries Survey of the San Juan River, Utah 1988.
• USFW Year: 1988.
• USFW - Doc Type: Salt Lake City, Utah.
• Copyright Material: NO

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ABSTRACT OF THESIS
CATOSTOMID FISHES OF THE
YAMPA AND WHITE RIVERS, COLORADO
The catostomid fish communities of the Yampa and White
Rivers in northwestern Colorado were sampled by electro-
fishing from July, 1975, through October, 1976. Specimens
of pure and hybrid suckers were analyzed by morphometric,
meristic, electrophoretic and discriminant function methods,
and populations of bluehead suckers from four sampling sites
on the Yampa River were examined for variance in the depth
of the caudal peduncle.
Flannelmouth, bluehead and white suckers, and flannel-
mouth X white, bluehead X white, and flannel-mouth X blue-
head sucker hybrids were identified. Most morphometric
proportions and meristic counts of hybriJ sackers were
intermediate between parental values. Intermediacy of blue-
head X white and flannelmouth X white sucker hybrids was also
shown in the elect rophoretic analysis, but a small sample was
t,,-sted.
Blue.head and flannelmouth suckers were found at all
stations on the Yampa and White Rivers. luehead X white
and flannelmouth X white sucker hybrids occurred only in
the upper Yampa River and comprised as much as 29.2 percent
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