7375

• UCREFRP Catalog Number: 7375
• Author: Wengert, M. W.
• Title: Flaming Gorge Reservoir Fisheries Management Investigations Six Year Completion Report ‎(1977-1983)‎.
• USFW Year: 1985.
• USFW - Doc Type: \
• Copyright Material: NO

ABSTRACT
Flaming Gorge Reservoir is located in southwest Wyoming and northeast Utah
and is jointly managed by the two states. The reservoir has a maximum surface
area of 42,000 acres and is 91 miles long at a maximum elevation of 6,040 feet
above sea level. The reservoir has been divided into three distinct areas based
upon topography, geology, hydrographic features, limnology, and distribution of
fishes: Inflow Area, Open Hills Area, and Canyon Area.
Before the gates on the reservoir were closed and the reservoir began
impounding water in November 1962, the Green River was chemically treated with
rotenone to control undesirable fish species. Rainbow trout were initially
planted in the reservoir and provided an excellent fishery. Creel rates and
harvest peaked in 1965. A general decline of the rainbow fishery has occurred
since that time, primarily because of establishment and expansion of Utah chub
and white sucker populations. Brown trout were stocked in the Inflow Area in
1966 to utilize Utah chubs. By the late 1970's, Flaming Gorge was a.nationally
acclaimed trophy brown trout fishery. By 1980, a developing lake trout fishery
was also"recognized. Lake trout had become established through downstream drift
from the Finger Lakes in the upper Green River drainage. In 1982, management of
the reservoir was changed to recognize the trophy fishery represented by the
large brown and lake trout.
A total of 20.9 million trout were planted in the reservoir during the study
period (July 1, 1977-June 30, 1983). Most of the trout planted (75 percent)
were rainbow and 14.4 percent were brown trout. Two strains of cutthroat trout
and lake trout accounted for the rest. Most of the trout were barge-planted to
insure uniform distribution. Other game fish planted included kokanee salmon,
channel catfish and smallmouth bass. Forage fish introductions included the
Bear Lake sculpin and Bonneville cisco.
Over 3 million trout were marked during the study period to provide data on
movement, survival, longevity, growth, and return to the creel. Identification
of marked trout was done during creel surveys and trend sampling (gill nets and
purse seine).
Year-round programmed creel surveys were conducted in 1978 and 1982, using
angler interviews and aerial c9unts. During 1979, 1980, and 1981, creel surveys
were run from April-September and consisted of angler interviews only. Harvest
and use estimates are presented and compared with creel data from 1964-1977.
The data document the continued decline of the harvest, led by the collapse of
the rainbow fishery.
Analysis of the programmed creel data indicates a harvest of 155,755 fish in
695,817 man-hours at a rate of 0.22 fish per hour in 1978 and a harvest of
161,528 fish in 670,891 man-hours at a rate of 0.24 fish per hour in 1982.
Rainbow trout continued to lead the harvest followed by lake and brown trout,
smallmouth bass, kokanee salmon and cutthroat trout. The reservoir yielded an
average annual harvest of 4.7 pounds/acre during the project period.
Harvest of lake trout has increased dramatically since 1975. In 1979, about
2.4 pounds/acre of lake trout were harvested and an annual average of 1.6
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