7166

• UCREFRP Catalog Number: 7166
• Author: Miller, W. H., et al.
• Title: Yampa River Fishes Study
• USFW Year: 1982.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

SUMMARY
Historic flows of the Yampa River, largest tributary of the Green
River, have not yet been altered by dams. However, a large number of
water development projects are planned which may significantly impact
flows, and consequently, the endangered fish fauna. Several previous
investigators have indicated the importance of the Yampa River and the
upper Green River for endangered fishes, including the Colorado squaw
fish (Ptychocheilus lucius). Because of potential conflicts between
proposed water projects and the survival of endangered fishes, the U.S.
Fish and Wildlife Service (FWS) and the National Park Service (NPS)
proposed that a study of the Yampa River be initiated as part of ongoing
research (Colorado River Fishery Project) on the upper Colorado River
basin. The Yampa study was needed to: 1) supply FWS with information
needed to prepare Biological Opinions under Section 7 of the Endangered
Species Act, and 2) provide FWS and NPS with information needed for
planning purposes. The FWS and NPS signed a cooperative agreement in
the spring, 1981, to study fishes in the Green and Yampa rivers within
Dinosaur National Monument (DNM). FWS also initiated research on the
upper Yampa, above DNM, with funds provided by Congress. The study area
included 124 mi of the Yampa River, from Round Bottom downstream to the
Green/Yampa confluence, and 26 mi of the Green River, from the Green/`
Yampa confluence downstream to Split Mountain campground.
The overall study consisted of three major investigations: 1) a
standardized sampling program to characterize fishery habitat, fish
distribution and abundance; 2) a special investigations program which
included radiotelemetry studies of adult Colorado squawfish, and abun,
dance and distribution studies of young Colorado squawfish; and 3)
physical habitat modeling (PHABSIM) of representative and unique river
reaches. Eight homogeneous river reaches (designated as strata), on the
Yampa and four on the Green were delineated for fisheries investigations
and five stations were selected for physical habitat simulation surveys.
Five standardized fisheries sampling rotations were completed on each
stratum, including the lower Little Snake River, from April through
October 1981. Three to four surveys were conducted at each PHABSIM
station.
A total of 24 species representing 9 families was collected in the
Green (19 species), Yampa (24 species), and Little Snake (11 species)
rivers in 1981. Of the 24 total species found, nine were native (6
endemic to the Colorado River basin) and 15 were introduced species. The
total number of fishes generally increased upstream with the exception
of Cross Mountain Canyon (Stratum 5) and Juniper Canyon (Stratum 7). The
total number of fish species also increased upstream, and was due to the
appearance of exotic species in samples. Most abundant native fishes
were bluehead and flannelmouth suckers, roundtail chub, and speckled
dace. Most abundant introduced species were red shiner, sand shiner,
redside shiner, fathead minnow, and channel catfish. Adult Colorado
v