HABITAT IMPROVEMENT
PROJECT
Fishery Division
otsoe STATE
-4.111.11111144
SAME COMMISSION
OREGON STATE GAME COMMISSION
NUMBER 9
P. 0. BOX 3503
Upper Cow Lake
Completion Report
PORTLAND, OREGON 97208
STATE OF OREGON
OREGON STATE GAME COMMISSION
FISHERY DIVISION
C. J. Campbell, Chief of Operations
Upper Cow Lake and Tributaries
Rehabilitation Project
Federal Aid in Fish Restoration Project
F-20-D-21
Post-Treatment Report
By
Lawrence.E. Bisbee
District Aquatic Biologist
NUMBER 9
Upper Cow Lake
Completion Report
View of Upper Cow Lake from outlet.
Rock dam and outlet works at Upper Cow Lake. Water flows into
irrigation canal or through spillway to Lower Cow Lake.
- 1 -
upper Cow Lake and Tributaries Rehabilitation Project
Post-treatment Report
ABSTRACT
Upper Cow Lake located in Malheur County, Oregon has a surface area of 975
acres and a volume of 7,150 acre-feet of water.
Chemical treatment of the lake was
completed September 11, 1963 to remove an abundant population of coarsescale suckers,
bridgelip suckers, squawfish, black bullhead, shiners and dace.
Approximately 55 miles of tributary streams above the lake were chemically
treated in August and September 1963.
The preparation and treatment of the reservoir were detailed in a Progress
Report, printed and distributed under the Habitat Improvement Project, Fishery
Division series, Report Number 6.
The present report covers the work accomplished
after the chemical treatment to December 31, 1964.
Restocking
Restocking of fry and fingerling trout in Upper Cow Lake commenced on April 14,
1964.
1.
The information on trout releases completed in the lake is presented in Table
Table 1:
Trout Releases in Upper Cow Lake in 1964
Pounds
Number per Pound
Date
Species
Number
April 14
Rainbow
99,900
999
100
July 17
Cutthroat
88,878
22
4,000
October 1
Rainbow
12,994
1,000
13
October 2
Rainbow
12,196
1,000
12.2
October 10
Rainbow
32,500
8
246,468
3,029
11
L
4,000
Lahontan stock
L2 New Zealand stock
Lake Survey
Water temperatures and dissolved oxygen samples were taken during the peak of
Water temperatures and dissolved oxygen
the hot summer weather in Upper Cow Lake.
content appeared to be favorable for trout during the periods tested.
atures and dissolved oxygen data are presented in Table 2.
located in three sections of the lake.
Water temper-
Collection stations were
Station Number 1 was in the center of the
deep western end and Number 2 at the narrows near the center and Number 3 in the
shallow southeast corner near Cow Creek.
3
Table 2:
Date
Location
Item
Water Temperature in Degrees Fahrenheit, Dissolved Oxygen in Parts
per Million and Ph Concentrations Measured at Upper Cow Lake, Oregon,
1964
July 6, 1964
Station 1
Temp. Oxygen Ph
Air
80.0
Surface
77.0
July 6, 1964
Station 3
Temp.
July 27, 1964
Station 1
Oxygen Ph
8.0
79.5
Oxygen Ph
87.0
87.0
80.0
7.6
Temp.
July 28, 1964
Station 2
Temperature
8.0
7.8
76.o
78.5
8.6
Depth in
feet
75.0
8.2
1
76.5
79.5
76.o
2
71.0
76.o
76.0
73.0
3
66.o
74.o
76.0
72.0
4
64.5
70.0
76.o
72.0
5
64.0
76.0
71.5
6
64.0
7
63.5
72.0
67.0
8
63.5
69.5
66.5
9
63.5
68.5
10
63.5
11
63
Date
Location
Item
66.0
7.4
63.0
87.0
Surface
78.5
75.5
7.1
67.5
7.0
69.0
6.6
66.5
July 28, 1964
Station 3
Temp. Oxygen Ph
Air
7.8
7.1
8.6
August 14, 1964
Station 1
Temp.
Oxygen
August 14, 1964
Station 2
Temp.
Olygen
August 14, 1964
Station 3
Temp.
Oxygen
68,0
68.o
71.0
71.0
74.o
79.0
74.0
77.0
Depth in
feet
7.0
1
78.5
69.2
2
77.o
69.0
74.0
72.0
3
77.0
69.0
73.0
69.o
4
72.0
67.0
72.0
68.0
5
68.5
66.5
67.5
6
67.5
66.o
66.2
7
67.5
66.o
66.2
5.8
8
66.o
9
66.0
6.6
4
7.1
7.8
66.2
66.2
7.2
Bottom food samples were taken at several stations on July 6, 1964 to
determine the effects of the eradication of trash fish populations on bottom
A summary of the data is presented in Table 3.
food organisms.
Table 3:
Summary of Thirty Bottom Samples Taken at Three Stations
in Upper Cow Lake on July 6, 1964
Station Number
1
Station location
Center of lake
Center of south- Center of northeast arm
east arm
No. samples taken
10
10
10
Bottom type
Silt
Silt
Silt
Depth range
11 feet
6 feet
7-8 feet
Summary
4
3,
30
6-11 feet
Total
Number of aquatic organisms
Percent of total
Chironomidae
51
7
54
112
39.6
Annelida
61
34
39
134
47.3
Hirudinea
16
11
6
33
11.7
2
1
3
1.1
1
1
101
283
Ephemeridae
Amphipoda
Total
128
54
211_
100.0
CREEL CENSUS
The first anglers began fishing Upper Cow Lake about August 1, 1964 when fish
population studies indicated the trout were of legal size.
Angling pressure on
the lake was very light and little effort was made to collect creel information
the first year.
There was a brief period in September when anglers fishing the
lake had good success.
Information obtained from one party of six anglers indi-
cated they had taken 23 rainbow in 12 hours of effort for a success of two
5
fish per hour.
Few anglers fished the lake because of the remoteness of the area,
the lack of a good road for public access and very little publicity.
The Malheur
County court is building a new access road in cooperation with the Bureau of Land
Management and the Oregon Game Commission.
Angling pressure is expected to increase
when the road is completed.
Fish Population Studies
Fish populations in Upper Cow Lake were sampled on July 28, 1964 to check on
the growth rate of the trout and reinfestation of rough fish.
population samples was taken on November 19, 1964.
A second series of
Results of the population studies
are listed in Table 4.
Table 4:
Date
July 28
Results of Fish Population Samples Taken in Upper Cow Lake
on July 28 and November 19, 1964
No. Net Sets
Gill nets Trap net
5
1
Species
Taken
Rainbow
trout
Number of
Fish in Sample
Gill nets Trap nets
120
Bridgelip
sucker
1
Coarsescale
sucker
2
Redside
shiner
4
Li
Rainbow
trout
Coarsescale
sucker
LI_
3
5 - 10
39.1
10
0.3
2 - 17
1.6
138
1 - 4
43.8
48
1 - 3
15.2
50
6 - 13
92.6
4
16
Dace
Nov. 19
3
Size Range Percent
in Inches of Catch
The trap net was not set because of ice cover.
- 6 -
7.4
A small number of coarsescale suckers and bridgelip suckers were captured
in the nets.
the trap net.
A good number of redside shiners and speckled dace were taken by
An extremely heavy runoff from Cow Creek probably accounted for
the rapid infestation of shiners and dace.
It is thought that the large suckers
entered Upper Cow Lake from Lower Cow Lake during the historically high spring
runoff.
Stop boards in the dam at the outlet of Upper Cow Lake were removed to
prevent flooding of the private property at the upper end of the lake.
It is
planned in the future to construct a rock barrier to fish at the lake outlet.
Growth rates for the rainbow fingerling stocked on April 14, 1964 were
considered to be excellent.
The trout averaged three inches in length when
stocked in April and averaged 11.2 inches fork length in November, 1964.
Growth
rate averaged 1.2 inches per month.
A stomach analysis was completed on 18 trout taken in the July 28, 1964
population samples.
the samples.
An abundance and variety of food organisms were found in
A summary of the data is presented in Table 5.
Rainbow trout 10 to 13-inches in length collected at
Upper Cow Lake by gill net on November 19, 1964.
The
trout were stocked as 2- to 4-inch fingerling on April 14,
1964.
- 8
Table 5:
A Summary of Stomach Analysis Data Obtained from
18 Rainbow Trout Taken by Nets in-Upper Cow Lake
on July 28, 1964
Aquatic Organism
Number
Percent of total
Water boatmen (Corixidae)
254
43.1
Freshwater shrimp (Gammaridae)
251
42.6
Back swimmers (Notonectidae)
53
9.0
Water mites (Hydrachnidae)
12
2.1
Mayfly larvae (Ephemeridae)
9
1.5
Diptera larvae
3
0.5
Damsel fly nymphs (Zygoptera)
2
0.3
Snails
2
0.3
Diptera pupae
1
0.2
Beetles, adults (Coleoptera)
1
0.2
Leeches (Hirudinea)
1
0.2
Crustacea
LI Mostly Daphnia
Common
Biological investigations, creel census, fish population studies and
stocking will continue at Upper Cow Lake as part of the normal fishery district
management activities.
Financial Statement:
Project approval:
Actual expenditures:
$
13,000.00
12,774.70
Approved by:
Submitted by:
obert L. Borovicka
Coordinating Fishery Biologist
Lawrence E. Bisbee
District Aquatic Biologist