8030

• UCREFRP Catalog Number: 8030
• Author: Tyus, H. M., C. W. McAda and B. D. Burdick.
• Title: Green River Field Investigations
• USFW Year: 1981.
• USFW - Doc Type: 1979-1981 Draft of the Final Report.
• Copyright Material: NO

Funnel-type wire traps of 1 in chicken wire approximately 1.5 ft in
diameter by 2 ~ ft long were set among large boulders or accumulations
of debris.
Compact, durable, time efficient equipment was procured to collect
physical and chemical data. This included the Marsh-McBirney Model 201
portable water velocity meter, a direct-readout device. Water velocity
measurements were taken at 0.6 distance from the surface. Water depths
were recorded with a collapsible stadia rod and a Lowrance depth finder
(Model LRG 1510A).
Total dissolved solids, salinities and conductivities were measured
with a Yellow Springs Meter (Model 33) which had a combined conductivity
and temperature probe. Conductivity was expressed as micromhos per
centimeter. Salinity was temperature compensated and recorded in grams
per kilogram. A Hach colorimeter (Model DR/1) was used to measure
dissolved oxygen and turbidity. Turbidites were measured in forazin
turbity units (FTU) which are equivalent to Jackson turbidity units.
No single technique efficiently sampled all habitats for all sizes
and species of fish. Every attempt was made to use gear or combinations
of gear that would provide a good cross-section of the fish population
in each habitat. The gear most utilized were seines. While a variety
of seine sizes and meshes were used, '~ in mesh nets were used predominantly.
Seines were hung with double weighted lead lines so they would stay
on the bottom in all anticipated current velocities. The catch per
effort was measured by the number of fish captured in a given area,
i.e., length of seine multiplied by the distance pulled.
Several boat sizes were used but the unit that was the best adapted
to general river use was a 16 ft (4.9m) flat bottom boat powered with a
25-hp outboard. The turbulent sections were traversed .with 18 ft (S.Sm)
rubber rafts.
Special Investigations
Abundance and Distribution of Young Colorado squawfish
The Vernal Field office initiated a special investigation in the
late summer-early fall of 1979 to obtain information about early life
history of Colorado squawfish. Directed toward "f illing 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 RM 363 (KM 581) at the upstream end of Dinosaur National Monument
and extended to RM 22 (KM 35.2) near the confluence of the Green and
Colorado Rivers.
Due to limited manpower, a knowledge of young squawfish behavior
(based on field work and information from others) was applied in developing
a sampling program. In 1979, all backwaters encountered were sampled.
In 1980, a limited sampling of shoreline habitat near the sampled backwaters