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

was added and the number of backwater/shore habitat sampled was restricted
to approximately one location per 3.2 km (2 mi) of river. After sampling
the first backwater encountered, no more samples were taken for two
river miles (3.2 km), then the next backwater encountered was sampled
and so forth. In addition, seine hauls were made in shoreline habitats
near the mouth of each sampled backwater. Collections in 1979 were made
with one-=quarter and one-eighth inch (0.3 cm) mesh seines. However,
little was gained at the expense of extra effort; therefore, in 1980
only one-quarter inch ((0.6 cm) mesh seines were used as a standardized
collection tool. Data obtained from these collections were recorded in
the same manner as in the standardized program.
In 1981 additional changes were made in the sampling design in
order to make this investigation more 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
squawfish. The larval collections were made as follows:
1. At the top of each stratum, each team proceeded downstream 5
mi (8 km) and initiated sampling at that location. All required
habitats were sampled with a larval seine (about 0.2 cm mesh)
in the first initial 0.5 mile reach. If all habitats are not
available in the initial 0.5 mile reach, such lacking habitat
was searched for and sampled in the remaining 4.5 mi of the
section. Records were kept of effort and the depth, velocity
and substrate of each sample was recorded.
2. In addition to the quantitative collections outlined above,
qualitative samples were also taken, using a larval dip
net. The investigators actively searched out larvae
(any habitat) at the site of the seine collections. A
sample of these larvae were taken with a dip net. In addition,
other samples were taken and accurate records were kept for
each collection.
3. The investigators then proceeded to the beginning of the next
5 mile section and repeated the process.
Samples were collected over three habitats: backwaters, eddies and
shorelines. The number of samples collected per habitat are given
below:
1. Backwater (4 collections)
a. deep (2)
b. shallow (2)
2. Eddy (4 collections)
a. deep (2)
b. shallow (2)
3. Shoreline (6 collections)
a. vegetation (2)
b. gravel/cobble (2)
c. sand/silt (2)