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

Water velocity was measured with a direct-reading Marsh-McBirney
Model 201 water velocity meter. Water velocity measurements were taken
at 0.6 distance from the surface. Water depths were measured with a
collapsible, stadia rod and a Lowrance Model LRG 1510A depth finder.
Total dissolved solids, salinities and conductivities were measured
with a Yellow Springs Model 33 meter with a combined conductivity and
_ temperature probe. Conductivity was expressed as micromhos per cen-
timeter and adjusted to 25°C. Salinity was temperature compensated and
recorded in grams-per kilogram. A Hach Model DR/1 colorimeter was used
to measure turbidity in formazine turbity units (FTU), equivalent to
Jackson turbidity units. Dissolved oxygen readings were taken using a
Hach Field Kit.
Several boat sizes were used but the best adapted unit for general
river use was a 16 ft flat bottom boat powered with a 20-hp jet drive
outboard. In whitewater canyon areas, downstream from Deerlodge Park,
inflatable rafts (13'6" Campways Miwoks; 18' Campways Havasus) and
canoes (17' Blue Hole whitewater canoes) were used.
Special Investigations
Abundance and Distribution of Young Colorado Squawfish
The Vernal Field Office initiated a special investigation in late
summer-early fall, 1979, on the Green River to obtain information about
early life history of Colorado Squawfish. In 1981 a similar investi-
gation was initiated on the Yampa River. Oriented toward "filling in"
needed information not obtained by the standardized sampling program;
this special effort was designed to evaluate the distribution and
abundance of young-of-the-year (YOY) Colorado squawfish. Collections
were made from Cross Mountain Canyon in Colorado, RM 56.1 (89.8 km),
downstream to the confluence of the Yampa and Green rivers and thence
downstream to Split Mountain.
Due to limited manpower, knowledge of young squawfish behavior was
applied in developing the 1981 sampling program for the Yampa River. 19$1
sampling was designed to be compatible with work in progress by the
Colorado Division of Wildlife. Larval fish collections were made in
addition to collections for the larger (30-70 mm) young Colorado squaw-
fish. The larval collections were made as follows:
1. Investigators proceeded downstream 5 mi (8 km) from
the top of each stratum, and initiated sampling at
that location. All required habitats were sampled
with a larval seine (about 1/16 in mesh (1.6 mm) in
the first 0.5 mi (0.8 km). If all habitats were not
available in the initial 0.5 mi (0.8 km) reach, the
investigators searched on and sampled such lacking
habitat in the remaining 4.5 mi (7.2 km) of the
section. Records were kept of the area sampled and
the depth, velocity and substrate of each sample.
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