7780

• UCREFRP Catalog Number: 7780
• Author: Brooks, J. E., et al.
• Title: San Juan River Seven Year Research Program Summary Report 1992.
• USFW Year: 1992.
• USFW - Doc Type: \
• Copyright Material: NO

discontinued. However, because of their extreme rarity, razorback
sucker that seasonally congregrate in the upper San Juan River arm
should be further studied to determine distribution relative to
reservoir elevation changes and habitat needs. Two low velocity
sampling trips will be conducted from Clay Hills (RM 4.0) to the
confluence with Lake Powell in 1993. The purpose of the two
sampling trips is to determine the presence of young-of-year
Colorado squawfish displaced from upstream reaches.
Tributary Fish Community Surveys - Fish community surveys were
conducted on portions of nine tributaries of the San Juan River
during July, August and September, 1992. The surveys included
locations on the mainstem San Juan River (upstream of Navajo
Reservoir), Los Pinos River, Piedra River, Animas River, Florida
River, La Plata River, Navajo River, Stollsteimer Creek, Rock Creek
and McElmo Creek in Colorado, New Mexico and Utah. All rivers
surveyed contained populations of native fish species. A total of
fourteen species, five native fish species and eight non-native
fish species, were collected during the survey.
Three native fish species were abundant in all rivers; speckled
dace, flannelmouth sucker, and bluehead sucker. Mottled sculpin
(Cottus bairdi) was common in the Animas and San Juan rivers.
Roundtail chub was collected in the San Juan River upstream of
Navajo Reservoir and the La Plata River in New Mexico.
The most collected non-native fish species included fathead minnow
(Pimphales promelas), rainbow trout (Oncorhynchus mykiss), brown
trout (Salmo trutta) and white sucker (Catostomus commersoni).
White suckers were collected in all rivers except the La Plata.
Hybrids- of native suckers and white suckers were collected in
rivers upstream of Navajo Reservoir and 'the Animas, and Florida
rivers.
McElmo Creek was the only San Juan River tributary in Utah
intensively sampled in 1992. Chinle Creek, the only other
tributary in Utah with sufficient flow for sampling, was not
sammpled because of difficulties with access. Non-native fathead
minnow was the most abundant species found in McElmo Creek. No
rare fish were found in Utah tributaries in 1992.
Native fish species were generally more abundant than non-native
fish species in all rivers sampled. Native fish species were
distributed throughout the sampling area. Roundtail chub was
collected only at two sites.
Tributary streams that will be sampled in 1993 include the Mancos
River, Navajo Wash (tributary to the Mancos), McElmo Creek
(Colorado), Animas River (New Mexico), Navajo River (New
Mexico),and additional sites on the Florida and La Plata rivers.
Flow and Habitat Relationships - This study utilized airborne
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