8SA/1 5B2 0
MERCURY CONCENTRATIONS IN FISH IN LAKE OAHE, SOUTH DAKOTA
APRIL 16 to SEPTEMBER 27, 1972
TECHNICAL SUPPORT BRANCH
_____ SURVEILLANCE AND ANALYSIS DIVISION
U S ENV IRONMENTAL PROTECT ION AGENCY

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                       ACKNOWLEDGEMENT
     This report is the final product of a joint state and federal
endeavor involving the Environmental Protection Agency, Food and Drug
Administration, Bureau of Sport Fisheries and Wildlife, South Dakota
State Health Department and South Dakota Department of Game Fish and
Parks.  The assistance of the following personnel is also acknowledged:
Mr. Marv Allum, State Health Department, coordination of state imput;
Mr. Bob Hanten and staff, State Game Fish and Parks, assistance in
survey planning and collection of control fish from Lake Enemy Swim;
Mr. Fred June and staff, Bureau Sport Fisheries and Wildlife, assistance
in survey planning and fish collection; Messrs Gerald Kaiser, Lee Ischinger
and Tom Nelapa NFIC-Cincinnati, EPA, assistance in fish collection and
Messrs Ron Eddy, Wayne Swallow, Mike Fillinger and Bill Warner, Region VIII
EPA, assistance in fish collection and data preparation; Mr. Tom Entzminger,
EPA, Region VIII, computer programming and statistical analysis.  Mr. Loys
Parrish, EPA Region VIII coordinated the study and prepared the final
report.

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TABLE OF CONTENTS
Page
INTRODUCTION . . 1
METHODS . 2
CHEMICAL ANALYSES 4
RESULTSANDDISCUSSION. . . . . . . . . . . . . . . . . . . . 4
CONCLUSIONS 20
APPENDIX. . . . . . . . . 22
Description of Nets 23
DetailedChemica lMethods 23
List of References. . 24
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LIST OF FIGURES
Figure No. Title Page
1 Oahe reservoir - fish sampling locations 1972. 3
2 Percentage of the total catch at each station equal 7
to or greater than 0.5 ppm mercury.
3 Percentage of fish equal to or greater than 0.5 ppm 8
mercury, at each sampling location, during each
sampling period.
4 Number and percentage of the total catch of each species 9
> 0.5 ppm mercury from the Cheyenne-upper arm (Foster
Bay) area during each sampling period in 1972.
5 Number and percentage of the total catch of each species 10
> 0.5 ppm mercury from the Cheyenne-middle arm (Fish Gut,
Minnconjou) area during each sampling period in 1972.
6 Number and percentage of the total catch of each species 11
0.5 ppm mercury from the Cheyenne-lower arm (Oak Creek)
‘ area during each sampling period in 1972.
7 Number and percentage of the total catch of each species 12
> 0.5 ppm mercury from Whitlock Bay during each sampling
period in 1972.
8 Number and percentage of the total catch of each species 13
> 0.5 ppm mercury from the Oahe Dam Tailrace area during
each sampling period in 1972.
9 The mean mercury concentrations (ppm) and 99% confidence 14
limits of the means for each species sampled from the
Cheyenne-upper arm (Foster Bay) during each sampling
period in 1972.
10 The mean mercury concentrations (ppm) and 99% confidence 15
limits of the means for each species sampled from the
Cheyenne-middle arm (Minnconjou, Fish Gut) during each
sampling period in 1972.
11 The mean mercury concentrations (ppm) and 99% confidence 16
limits of the means for each species sampled from the
Cheyenne-lower arm (Oak Creek) during each sampling
period in 1972.
12 The mean mercury concentrations (ppm) and 99% confidence 17
limits of the means for each species sampled from Whitlock
Bay during each sampling period in 1972.
13 The mean mercury concentrations (ppm) and 99% confidence 18
limits of the means for each species sampled from the Oahe
Dam Tailrace area during each sampling period in 1972.
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.LIST OF TABLES
Table Title P-age
1-A Total number of each species of sport fish sampled per 5
sampling period.
Appendix
1-A Length (mm), weight (grams), mercury content (ppm) and 25
type of fish caught during each sampling period, at
each sampling location.
2-A Results of statistical analyses on mercury concentrations 52
in fish samples.
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INTRODUCTION
This report presents the results of intensive surveys conducted
during the period of April 16 to September 27, 1972, to determine
the mercury content of sports fish in Oahe Reservoir, South Dakota.
The survey was initiated at the recommendation of the conferees to
the Enforcement Conference in the Matter of Pollution of the Navigable
Waters of Western South Dakota, convened on October 19, 1971 in Rapid
City, South Dakota.
Mercury contamination of the environment was discovered to be an
important problem in the United States in the early part of 1970.
Subsequent to the initial identification of the problem, State and
Federal Governments conducted industrial surveys to identify mercury
users, to determine their impact on the environment and to initiate
waste controls. These surveys revealed gold mining operations as one
of the significant producers of mercury laden wastes. The Homestake
Mining Company, Lead-Deadwood mill in South Dakota, used mercury in its
gold mining processes from the latter part of the nineteenth century
to early 1971. Wastes from the mining operation are discharged to
Whitewood Creek which is tributary to the Cheyenne River system which
enters Oahe Reservoir. The company ceased the discharge of mercury
in 1970 but a residual stream bed load remains in the tributary system
(Division of Field Investigations-Denver, 1971).
Several studies were conducted by State and U.S. Bureau of Sport
Fisheries and Wildlife personnel during May, 1970; late July and early
August, 1970; and October 13 and 14, 1970 to determine the mercury
levels of fish in the Cheyenne Arm of Oahe Reservoir. Tissue analyses
of the co1lected samples revealed fish with mercury concentrations greater
than 0.5 parts per million (ppm) mercury. This level is in comparison
to the Food and Drug Administration recommendation that fish containing
0.5 ppm or greater mercury “should” not be eaten. On April 23, 1971
Governor Richard F. Kneip, of South Dakota, requested that the Environmental
Protection Agency call a conference to consider the problem of actual or
potential mercury toxicity to humans from the consumption of fish flesh
and water from the Cheyenne River System including the Cheyenne Arm of
Oahe Reservoir (Environmental Protection Agency, 197la). Held on October
19 through 21, 1971 the Conference produced the recommendation that EPA,
the State of South Dakota and the U.S. Food and Drug Administration
develop a study plan to provide the quantitative data necessary for a
definitive assessment of the health hazard posed by mercury in Oahe
fish and sediments in Oahe Reservoir. The study plan, as implemented,
represented the consensus of representatives of the South Dakota State
Health Department and Department of Game, Fish and Parks, the U.S.
Bureau of Sport Fisheries and Wildlife, EPA, and the U.S. Food and Drug
Administration.
In this report all total mercury concentrations equal to or greater than
0.5 ppm are considered significant. This is in agreement with an EPA posi-
tion document (EPA, l97lb) which stated: “EPA will consider that when a range
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of fish species in an inland or estuarine body of water have residue
levels of mercury equal to or greater than 0.5 ppm that there is an
indication of gross mercury pollution and that consumption of fish
from such a body of water would represent a hazard to health.” This
is consistent with the FDA guidance.
Recent reports have indicated a concern about the fact that the
amount of methylmercury present in fish flesh may be considerably
less than the total mercury measured (Anon.,, 1973). Other forms of
mercury,, less toxic than methylmercury, occur in the aquatic environ-
ment and if present in fish would also be measured as total mercury.
However, a report by Gavis, et.al, (1972) indicates that at least 90
per cent of the mercury in fish analyzed was in the form of methylmercury.
Fimreite, et,al, (1971) tested five specimens of walleye which had an
average of 95 per cent of total mercury as methylmercury. In a more
recent study Henderson et.al (1972) analyzed composite fish samples
from selected waters of the United States, compared total and methyl-
mercury results, and concluded that at least 90 per celit and possibly
more of the mercury in fish is methylmercury. The Food and Drug Admin-
istration still considers all mercury in fish flesh to be toxic until
disproven by future studies (Personal Communication, 1973). All mercury
levels reported herein will be considered conservatively, methylmercury.
METHODS
The fish sampling program involved the six locations listed below
and shown in Figure I.
1. The Cheyenne-Upper Arm (Foster Bay and Upstream).
2. The Cheyenne-Middle Arm (Minnconjou-Fish Gut).
3. The Cheyenne-Lower Arm (Oak Creek-Rosseau Creek).
4. Whitlock Bay.
5. Tailrace of Oahe (Stilling Basin)-control station.
6. Lake Enemy Swim, Day County,, South Dakota-control station.
State and Federal authorities have speculated that mercury deposits
in the’ Black Hills and in marine shales throughout Western South Dakota
may cause natural mercury pollution in Oahe Reservoir, As a check on
this possibility, Lake Enemy Swim, in the North Eastern section of the
state was selected by the Department of Game, Fish and Parks as a control
outside the influence of marine shales or man-made contamination.
Dates for the specific sampling periods were as follows: Spring
4/16 - 4/26 and 5/17 - 5/22, Sumer 6/21 - 6/28,, and Fall 9/19 — 9/27.
Since sport fishing pressure was judged by the Department of Game, Fish
and Parks to be twice as heavy during the spring season as compared to
summer or fall, the spring season was divided into two sampling periods.
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‘0
& 8M 1
1
S
12.87 KM
• — fish sampling locations
FIGURE 1.
OAHE RESERVOIR
“p
\0
3
\0
SOUTH DAKOTA
OIR
Oah.
Toil Watir
fish sampling locatIons, 1972
hitlock
B
ly
C,
I
—3-

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Primary sport fish sampled from Oahe Reservoir and the total number
of each species per sampling period are listed in Table 1. A three
day sampling period was sufficient to collect most species of fish.
If less than the required number of fish was collected in any three
day period the number collected represented the sample. Fish were
randomly selected from the nets to insure the adequate collection of
all sizes. The minimum length of each species was determined by
observing the sizes of fishes retained by sportsmen fishing the reservoir.
Each fish was identified, weighed, measured, and sexed. Scale samples
were collected for age determination (to be accomplished at a future
date). A randomly selected fillet from each fish was packaged individually,
tagged, frozen and transported to the Regional Lab in Denver for disposition
All fish were collected with either experimental sinking gill nets
or frame nets set for approximately 24 hours. Detailed descriptions
of the nets are in the Appendix.
CHEMICAL ANALYSES
Fish samples were analyzed by the Ute Research Laboratories, Fort
Duchesne, Utah and by the National Field Investigations Center-Cincinnati
Office of Enforcement and General Counsel, EPA. Brief descriptions of
the methods used are in the Appendix.
RESULTS AND DISCUSSION
The concentrations of mercury found in sport fishes, collected from
Oahe Reservoir during the survey periods, are listed in Table 1, Appendix.
The length, weight and sampling location for each fish are also listed in
the same Table. The results of statistical analyses on mercury concentra-
tions in fish samples are listed in Table 2, Appendix. Total mercury
concentrations are listed as reported by each testing laboratory. The
National Field Investigations Center-Cincinnati reported values to the
nearest 0.1 mg of mercury (Hg) per kilogram (Kg.) wet weight of flesh.
The Ute Research Laboratories reported concentrations to the nearest
0.01 mg Hg/Kg. Although the Ute Research Laboratory data are reported
to the nearest 0.01 mg Hg/Kg in Table 1, Appendix, comparative analysis
of the data considered values rounded to the nearest 0.1.
A total of 1032 sport fishes from Oahe Reservoir and its tailwaters
were analyzed for mercury content. Twenty-eight per cent (286) contained
mercury concentrations equal to or greater than the FDA guideline of
0.5 ppm. This compares with approximately 76 out of 295 or 26 per cent of
the fish collected from the same areas in 1971 (Division of Field Investi-
gations-Denver, 1971). Thirty-six per cent or 234 out 651 fish netted
from the Cheyenne Arm contained amounts of mercury equal to or greater
than 0.5 ppm.
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TABLE 1. Total number of each species of sport fish sampled per
sampling period.
Fish Sample number
Walleye Stizostedion vitreum vitreum 8
Northern Pike Esox lucius 6
Channel Catfish Ictalurus punctatus 10
White Bass Morone chrysops 10
Sauger Stizostedion cánadense 8
*Crappje (Black & White) Pomoxis nigromaculatus
end P. annularis 10
*yellow Perch Perca flavescens 10
* These species were to be sampled and information from them used when
any of the first five were not available.
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Figure 2 shows a comparison of the total numbers of fish caught
to the number containing 0.5 ppm mercury or greater for each sampling
area. The largest percentage of fish containing high mercury concentra-
tions were collected from the upper arm (Foster Bay) area (122 of 258
or 47%). The middle arm (Minnconjou-Fish Gut) area yielded 69 of 217
or 32% of the fish contaminated with mercury at 0.5 ppm or greater
mercury. Oak Creek or the lower arm yielded a smaller number of fish
contaminated by mercury with 24% being at or above the 0.5 ppm concentration
The number of fish from Whitlocks Bay containing hazardous levels of
mercury were comparable in quantity to the Oak Creek area of the Cheyenne
Arm. Since there are no known industrial sources of mercury discharging
to the area, the elevated concentrations in Whitlocks Bay appear to be
caused by natural sources. However, there is Insufficient data to
support such a conclusion. Fish from the tailrace area of Oahe were
relatively free from mercury with only 8 of 138 or 6% containing 0.5
ppm or greater. The control lake Enemy Swim had only one fish in the
0.5 ppm or greater range.
Figure 3 shows the percentages of fish at or above 0.5 ppm at each
sampling station for each sampling period. From April to September 1972
there was a general decline in the percentages of fish with hazardous
mercury concentrations. The upper arm (Foster Bay) contained the highest
percentages followed by the middle (Minnconjou) and lower arm (Oak Creek)
areas. The general decline of high mercury concentrations from the upper
arm to the lower arm agrees with the findings of DFIC-Denver (1971). The
lower arm (Oak Creek) area shows an increase in fish containing mercury
in September which was attributed to white bass that had moved into the
area during the sampling period. Fish in Whitlock Bay increased in
percentage of contaminated individuals during June. If the source is
natural, the increase at Whitlock may have resulted from the rains
and runoff that occurred in early June before the sampling period.
Figures 4 through 8 depIct the total number of each type of sport
fish sampled and the number of fish containing 0.5 ppm mercury or greater
for each sampling location, during each sampling period. Figures 9
through 13 depict the mean mercury concentration for each species and the
99 per cent confidence limits at each sampling location, during each
sampling period.
Four out of five species of sports fish from the upper arm of the
Cheyenne had significant percentages of individual fish containing 0.5
ppm mercury or greater during the April sampling period (Figure 4).
The mean concentration of mercury for each species except sauger was
at or above 0.5 ppm (Figure 9), with walleye and northern pike containing
the highest mean concentrations of mercury. In May percentages of fish
with hazardous levels of mercury ranged from 25% to 100% (Figure 8).
Walleye, pike, white bass and crappie had the highest mean levels of
mercury. Channel catfish and sauger were lower than 0.5 ppm in mean
concentrations but the confidence limits for the means reached or exceeded
0.5 ppm (Figure 9). In June walleye, white bass and sauger still contained
significant amounts of mercury. Mean concentrations for these fish were
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300 —
250-
200
150-
Figure 2.
‘-47%
-24%
Upper Middle Lower
Arm Arm Arm
Percentage of the total catch at each station
greater than 0.5 ppm mercury.
flT
Percent of Catch,’ ‘Total
Catch
0.5ppm Hg I
I.,
I O
Lake
Enemy Swim
equal to or
100
0
.0
50
32%
l8%
Bay

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100
Foster Bay •
Oak Creek —.—.-
Minnconjou
Whitlock Bay———— *
80—
I
6O-
20—
I I I
April May June Sept
SAMPLING PERIOD
Figure 3. Percentage of fish equal to or greater than O.5ppm mercury,
at each sampling location, during each sampling period.

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* None Caught
N.Pike C.Cat W.Bass
Species of Fish
Figure 4. Number and percentage of the total catch of
O.5ppm mercury from the Cheyenne- upper
Bay) area during each sampling period in 1972.
No.? 0.5 ppm
Hg, (%)
Crappie
each species
arm (Foster
(87)
20
10
20
tO
(60)
T
Total No.
of Fish
U)
Li.
April
May
June
Sept
.4-
0
0)
0
E
z
2
I0
2
l0
0
Wcil ieye
I00)
(22)
(60)
*
(0)
Souger

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None Caught
I
—
(69)
(12)
(25)
Tfl
—(lo9
n
(40)
(50)
Total
of Fish
(6) (6 - -
No. 0.5 ppm
Hg, (%)
Walleye N. Pike C. Cat W.Bass Sauger Crappie
Species of Fish
Figure 5. Number and percentage of the total catch of each species
? 0.5 ppm mercury from the Cheyenne — middle arm (Fish Gut,
Minnconjou) area during each sampling period in 1972.
20
l0
20
10—
-C
U,
IL
April
May
June
Sept
0
10—
1
4 )
E
z
20
l0

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* None Caught
April
-C
U)
May
0
June
Sept
20
No. 0.5ppm
Hg, (%)
20
l0
20
I0
T
Total No.
of Fish
*
*
I0
(6)
10
*
C. Cat W. Bass Sauger Crappie
Species of Fish
Figure 6. Number and percentage of the total catch of each species
0.5 ppm mercury from the Cheyenne — lower arm (Oak Creek)
area during each sampling period in 1972.

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20
20
April
May •
I L.
•1-
0
* None Caught
Tfl
Total No.
of Fish
*
No. > 0.5 ppm
Hg, (%)
20
10
June ;
E
z
Sept
20
l0
Wall eye
Figure •7.
N. Pike C.Cat W. Bass Sauger Crappie
Spe des of Fish
Number and percentage of the total catch of each species
0.5 ppm mercury from Whitlock Bay during each sampling
period in 1972.

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* None Caught
April
May
U)
IL
I .-
0
June
.0
E
z
Sept
No. 0.5ppm
Hg, (%)
20
10
20
l0
*
T
Total No. -
of Fish
J-
20
*
*
l0
*
Walleye • N.Pike C.Cat W.Bass Sauger Crappie
Species of Fish
Figure 8. Number and percentage of the total catch of each
species O.5ppm mercury from the Oahe Dam tailrace
area during eachsampling period in 1972.

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1.0
April 0.5
E
0 .
U)
May 10:
g 1.0
C-)
>‘
I-
June 0.5
x 1.0
Sept 0.5
0
* None Caught
99% Confidence limits
J,’ of the mean
Mean
Walleye N. Pike C. Cat W. Bass Sauger Crappie
Species of Fish
Figure 9. The mean mercury concentrations (ppm) and 99% confidence limits of
the means for each species sampled from the Cheyenne —— upper arm
(Foster Bay) during each sampling period in 1972.
1 •L
1.0
0.5
0
1.0
0.5
0
1.0
•2.0
: 4
0
1.0
— - 0.5
* *
0

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1.0
April 0.5
- .0
0
0 .
U)
C
0
May 0.5
L.
C
C
1.0
>%
L
June 0.5
x
C
Q)
I.
Sept
0
£ Insufficient sample
* None Caught
Mean 99% Confidence limits
of the mean

-1--
H - ---:- -i----f -
Walleye
Figure 10.
N. Pike C. Cat W. Bass Sauger Crappie
1.0
0.5
0
1.0
0.5
0
1.0
0.5
0
Species of Fish
The mean mercury concentrations (ppm) and 99% confidence limits of the
means for each species sampled from the Cheyenne —— middle arm (M nnconjou,
Fish Gut) during each sampling period in 1972.
I-a
0 ,
I
I
1.0
*
0

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None Caught
April
1.0 -
0.5
E
0
in 1.0
C
0
.f-
May 0.5
4- I
C
U
U
C
0
I
I.
>..
L
U
June 0.5
C
a,
1.0
Sept 0.5
0
:i
Mean
*
99% confidence limits
of the mean
I *
-I
T
i ---i -:
- I -
Walleye N. Pike C. Cat W. Bass Sauger Crappie
1.0
0.5
0
1.0
0.5
0
1.0
0.5
0
1.0
0.5
0
Species of Fish
Figure 11. The mean mercury concentrations (ppm) and 99% confidence limits of the
means for each species sampled from the Cheyenne —— lower arm (Oak Creek)
during each sampling period in 1972.

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U)
C
0
to
May LO.5
4 .’
C
(5
U
C
0
0
>. I
L
U
June
C
(5
a)
1.0
• One Fish
* None Caught
Species of Fish
Figure 12.
The mean mercury concentrations (ppm) and 99% confidence limits of the
means for each species sampled from Whitlock Bay during each sampling
period in 1972.
April
1.0
0.5
0
Mean Confidence limits
of the mean
-
- I I
E
0
0.
I *
1.0
- 0.5
0
1.0
0.5
-
Sept 0.5
0
— — — — — — — — —— — __ f__....__ .
• I I -
Wa l leye N. Pike
0
1.0
0.5
0
1.0
0.5
0
C. Cat
W. Bass Sauger
Crappie

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1.0
April 0.5 -
E
Q.
0.
1.0
U I
C
0
May 0.5
June
1.0
Sept 0.5
0
Mean
£ Insufficient Sample
* None Caught
99% Confidence limits
of the mean
-- _I *
I
- I * * £ *
t
- I *
1.0
.5
0
1.0
D. 5
C
1.0
0.5
0
1.0
). 5
0
Wa lleye N. Pike C. Cat W. Bass Sauger Crappie
Species of Fish
Figure 13. The mean mercury concentrations (ppm) and 99% confidence limits of the
means for each species sampled from the Oahe Dam tailrace area during
each sampling period in 1972.
- A A *
*

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at or above the 0.5 ppm guideline. Channel cat and crappie had lower
mean concentrations of mercury, with the confidence limits for the
mean concentration in crappie extending over the 0.5 ppm level. Conditions
appeared to have improved in September with most percentages of affected
fish smaller than those in the other sampling periods (Figure 4). Walleye
and white bass contained significant amounts of mercury, with white bass
being higher in percentage of fish over the guidelir e and in mean mercury
concentration than in any other sampling period. Only one northern
pike was captured and it contained 2.0 ppm mercury. The mean concentra-
tion of mercury in channel cat increased from 0.3 to 0.4 ppm with
the confidence limits extending over 0.5 ppm mercury.
Fish from the middle arm (Fish-Gut-Minnconjou) of the Cheyenne
contained less mercury than those from the upper arm; even though
concentrations of mercury were still significantly high. In comparison
to fish in the upper arm, percentages of contaminated fish in the
middle arm were generally lower in number except for pike and sauger
which were higher in number during the April sampling period and white
bass which were higher in number in September (Figure 5). Numbers of
contaminated walleye, northern pike and channel cat were highest in
April. The highest percentages of crappie, sauger and white bass
equal to or greater than 0.5 ppm mercury occurred during the same
sampling periods in both the upper and middle arm areas (Figures 4 and 5).
Mean mercury concentrations were at or above 0.5 ppm for walleye and
pike in April, pike and crappie in May, sauger in June and white bass
in September. At any one sampling period at least two out of six
primary sport fishes collected had 25 per cent or more of their respective
populations at or over the 0.5 ppm guideline.
The lower arm of the Cheyenne contained smaller percentages of
mercury laden fish as compared to the upper or middle arm (Figure 6).
One notab1e exception is white bass with 85% of the population at or
over the 0.5 ppm guideline in September. Comparison of percentages
of mercury contaminated white bass in the Cheyenne Arm reveals a gradual
increase in the percentage of fish at or over 0.5 ppm from April to
September at each sampling location. Significant percentages of northern
pike in the lower arm exceeded the 0.5 ppm guideline in April and May.
In May the mean concentration of mercury in pike was less than 0.5 ppm
but the confidence limits of the mean extended above the 0.5 level.
Crappie contained significant amounts of mercury in May throughout the
entire Cheyenne Arm, while sauger were higher in mercury content in
June than in other periods of the year.
Whitlock Bay was sampled as a potential problem area, outside the
influence of the Cheyenne Arm. Previous surveys had reported fish that
contained concentrations of mercury over 0.5 ppm. In April and June
all of the fish species netted contained percentages of fish with mercury
concentrations equal to or greater than 0.5 ppm. In May white bass,
sauger and crappie had 29%, 33% and 70% of their respective numbers
high in mercury. Crappie contained the highest mean concentration of
mercury of any species captured from Whitlock Bay. During the September
sampling period a greater percentage of white bass were high in mercury
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concentrations similar to the same species in the Cheyenne Arm.
Crappie also tended to follow the same patterns of mercury concentration
in Whitlock and the Cheyenne Arm.
The taiIrace area of Oahe Reservoir represented a control station. Th
highest percentage of contaminated fish was 18 per cent of the catfish
caught in April (Figure 8). Only 6 to 12 per cent of the walleye
sampled had mercury concentrations at or above 0.5 ppm. None of the
species taken from the tailwaters had mean concentrations of mercury
at or above 0.5 ppm and the confidence limits for the mean concentrations
did not extend to or above 0.5 ppm (Figure 13).
In Lake Enemy Swim most of the fish sampled contained 0.3 ppm or
less mercury. Only one fish, a white bass, contained a higher amount
of mercury (0.6 ppm) than the 0.5 ppm guideline.
CONCLUSIONS
Thirty-six per cent of the fish sampled from the Cheyenne Arm of
Oahe Reservoir contained mercury at a concentration equal to or greater
than 0.5 ppm. Fish with the highest concentrations of mercury were
found in the upper arm or Foster Bay area with 50 per cent or more of
each specie containing hazardous levels of mercury during at least one
sampling period.
Fish from the middle arm did not contain concentrations of mercury as
high as those in the upper arm and the lower arm supported fish with
generally lower mercury concentrations than the middle arm, a pattern
noted by the Division of Field Investigations-Denver in an earlier
report. Both the middle and lower areas contained fishes with sufficient
concentrations of mercury to represent potential health hazards. In
the Cheyenne Arm white bass increased in percentage of affected fish as
the year progressed. Other species contained their highest concentrations
of mercury at different times of the year; walleye, and channel cat in
April, sauger in June and crappie in May. Pike were significantly high
in mercury concentrations during the entire survey. During the September
survey most fish except white bass had mercury levels less than 0.5 ppm.
Whitlock Bay contained contaminated fish, notably white bass,
crappie and sauger. White bass contained more mercury in September
while crappie concentrated more mercury in May; a pattern foflowed
by the same species in the Cheyenne Arm. More species of fish contained
0.5 ppm or greater mercury during the months of April and June, than in
May and September.
Fishes from the control areas (tailrace and Lake Enemy Swim) contained
small amounts of mercury and were not viewed as potential sources of
mercury contamination to man.
A report by Katz (1972) cites an international committee that con-
siders an intake of 1 mg/day of methylmercury as a toxic dose for
healthy adults, excluding pregnant women or other vulnerable groups.
- 20 -

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This is approximately 1/5 lb. of fish at loppm or 2 lb. at lppm.
In the same report it was noted that a Swedish toxicological committee
recommends a maximum acceptable intake of 0.03 mg/day for a 70 kg
(154 lb.) male, which is less than ½ lb of fish at lppm per week
without other intake of mercury from other food sources . With
the above values as a comparison, most species of sport fishes from
the Cheyenne Arm of Oahe Reservoir could pose a threat to the health
of anyone consuming them, especially during the spring season when
fishing pressure is twice a heavy as the rest of the year. The
consumption of white bass, crappie and sauger from Whitlock Bay
could also represent a health hazard. Fishermen who camp on the
shores of the reservoir and catch and eat fish from the reservoir
during their stay may be subjecting themselves to large doses of
mercury from contaminated fish.
Accordingly, it is recommended that the Cheyenne Arm of Oahe
Reservoir be posted at all accessible locations to warn the general
public of the potential health hazard from consuming fish taken from
this body of water. Similar posting may also be necessary at Whitlock Bay
advising fishermen to release selected species of fish. As a follow-up
to the posting of the Cheyenne Arm, investigatory studies should be
pursued to achieve a basic understanding of the mechanisms governing
the dynamic transport and cycling of mercury from sediment to fish
in this area of the reservoir. From these studies an assessment
should evolve of the feasibility and practicality of undertaking
specific actions, if any, to curtail the chain of transmission. Con-
current with these studies, periodic monitoring of mercury levels in
fish should be conducted to verify the need for continued posting.
It is possible that a certain mitigation of the problem could result
from the coverage of the mercury-bearing material with sediment carried
into the reservoir from upstream locations. However, the time response
of this natural process in terms of substantially decreased mercury
levels is an unknown and, perhaps, quite slow.
- 21 -

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APPENDIX
—22—

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Fish Nets
Gill nets were single strand monofilament 106.7 meters (350 ft.)
long with seven panels measuring 1.8 meters (6 ft.) by 15.2 meters
(50 ft.). Mesh sizes of the panels were as follows: 1.91 cm (3/4 in.),
2.54 cm (1 in.), 3.17 cm (1 1/4 in.), 3.81 cm (1 1/2 in.), 5.08 cm.
(2 in.), 6.35 cm (2 1/2 in.) and 7.62 cm (3.0 in.).
The frame nets had 0.91 meter (3 ft.) by 1.83 meters (6 ft.) frames
with 1.27 cm (1/2 in.) mesh netting. Each net had a 15.2 meter (50 ft.)
1 ead.
Chemical Procedures
Fish samples were analyzed by two different laboratories. Part of
the samples were analyzed by the Ute Research Laboratories, Fort Duchesne,
Utah with the following method:
1. The fillet is masserated using a high speed blender.
2. 1.000 gram (net weight) of fish tissue is weighed into a 0.118 1.
(4 oz.) polyethylene bottle.
3. 15 ml. of a 1:2 HC10 - HNO 3 mixture is added and the bottle
closed tightly.
4. The mixture is swirled-to disperse the sample and placed in a
water bath at 60° C for 8 hours.
5. 4 ml of DIH 2 O are added and the sample is heated an additional
2 hours to drive off NO fumes.
6. The sample is cooled an diluted to 50 ml with DIH 2 O.
7. (a) 5 ml of NaC1 - Hydroxylamine Hydrochloride solution (l2Og
NaC1 + 120g NH OH HCl/l) is added - wait 1 minute.
(b) 5 ml of st nnous chloride solution (113g 5nCl 9 2H 2 O + 170 ml
HC1/l) is added and the aerator Is immediately inserted into the
sample.
8. The sample is analyzed with a Perkin-Elmer 403 Atomic Absorption
Spectrophotometer* with a cold vapor mercury atomization attachment
• and an automatic electronic recorder. Strict quality control was
maintained (Ruckman, 1972).
The National Field Investigations Center-Cincinnati used the cold
vapor procedure basic to the Hatch and Ott method (1968) with the following
changes. Preliminary combustion of the sample at approximately 8500 C in
a closed tube-type furnace with collection of the liberated mercury in an
acid permanganate trap is followed by reduction of the mercury to the
metalic form and measurement with a Perkin-Elmer-Coleman mercury vapor
meter. All phases of the analysis were carried out under the strictest
quality control surveillance (Sanning, 1973).
* Mention of trade names or comercial products does not constitute
endorsement by Region VIII, Environmental Protection Agency.
- 23 -

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List of References
Anon., 1973. Mercury—in—fish standard. Sport Fishing Institute Bul. No. 242, 8p
Division of Field Investigations-Denver, 1971. Report on pollution affecting
water quality of the Cheyenne River system Western South Dakota. Division
of Field Investigations—Denver,. EPA, Office of Enforcement. 89pp.
Environmental Protection Agency, 197l,a. Conference in the matter of pollution
of the navigable waters of Western South Dakota. Proceeding. US-EPA, 596pp.
________________1971.b Proposed Environmental Protection Agency Position
Document-Mercury. US-EPA, 123pp.
Fimreite, N.,, W.N. Halsworth, J.A. Keith, P.A. Pearce and I.M. Gruchy. 1971.
Mercury in fish and fish eating birds near sites of industrial contamination
in Canada. Canadian Field—Naturalist, vol. 85, pp2ll-220.
Gavis, Jerome and John F. Ferguson. 1972. The cycling of mercury through the
environment. Water Research, vol.6, pp989-1008.
Henderson, Croswell, Anthony Inglis, and Wendell L. Johnson. 1972. Mercury
residues in fish, 1969-1970. National Pesticide Monitoring Program.
Pesticides Monitoring Journal 6 (3):l44-l59.
Katz, Arthur. 1972. Mercury pollution: The making of an environmental crisis.
CRC Critical Reviews in Environmental Control. January pp5l7-534.
Roy, Caesar, Assistant to the Director, Division of Regulatory Guidance,
U.S. Food and Drug Administration. 1973. Personal communication on
March 9, 1973.
Ruckman, Jack, Director, Ute Research Laboratories, Fort Duchesne, Utah.
Letter dated November 15, 1972.
Sanning, Donald E., Chemist, Chemistry Section, Water Science Branch, National
Field Investigation Center-Cincinnati, Office of Enforcement and General
Counsel, EPA. Memo dated March 27, 1973.
Hatch, W. R., and W. L. Ott. 1968. Determination of sub-microgram quantities
of mercury by atomic absorption spectrophotometry, Anal. Chem. 40, 2085.
- 24 -

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TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location.
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Upper Arm No. Pike 4/18 708 2211 1.7
H ‘I 690 3118 0.3
H 875 369 09
‘I I’ 1 775 3289 0.6
I’ 1 545 1588 0.3
I’ I’ H 620 1588 0.4
I’ 4/19 980 7031 1.2
‘I 1 685 3062 0 7
II ‘I 566 1474 0 4
I’ ‘1 523 1049 0.6
I’ ‘I 612 1588 0.4
Upper Arm C. Cat 4/18 417 794 0.2
‘I ‘I 388 624 0.1
‘I H 410 367 0.3
H 540 1814 0 8
II ‘I 4 5 907 0.7
II I’ 425 879 1 0
750 1984 1.3
I’ 490 1361 0.6
I’ 390 680 0 5
I’ ‘I 385 567 0 8
‘I “ I’ 350 454 0.4
‘I I’ 390 595 0 4
I I II 1 358 510 0.6
H ‘I 790 3118 1 .0
I’ 381 624 1.1
H I’ 1 345 510 03
‘I I’ 1 310 340 0 5
I’ 4/19 583 2778 0.2
H H U 373 567 0 6
“ I’ 357 510 0.4
Upper Arm V. Perch 4/18 160 113 0.1
4/19 229 284 0 3
“ H 191 113 0 1
I’ I’ 165 85 02
I’ I’ 200 113 0.1
25 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Upper Arm W. Bass 4/18 265 312 0.2
U U U 275 340 0.9
I’ 290 454 0.7
II I’ 308 510 0.9
I U 310 510 0.8
II. U 300 454 1.1
‘I U 260 312 0.3
I’ 270 369 0.3
‘I 265 312 0.6
I’ 260 312 0.4
‘I 258 312 0.2
‘I ‘I 279 369 0.2
I’ U 260 312 0.2
I’ ‘I 255 255 0.7
I’ 250 227 0.6
‘I I’ 260 284 0.3
I’ 1 215 142 0.3
° ° ° 242 227 0.3
° ° 265 312 0.5
250 255 1.2
Upper Arm Walleye 4/18 535 1049 0.4
° ° 425 907 0.7
° ° ° 515 1588 1.4
400 709 1.1
° ° 360 539 0.7
° ° ° 310 369 0.7
° ° 320 369 0.5
° 445 1021 0.6
° ° ° 435 907 0.3
455 1162 0.7
° ° 428 879 0.5
° “ ° 504 1474 1.4
° ° 393 709 1.0
° ° 410 850 1.3
420 964 0.5
Upper Arm Sauger 4/18 340 340 0.3
° ° 320 227 0.2
° ° ° 260 142 <0.1
° ° 250 142 0.2
° 320 255 0.4
° 246 113 0.2
° 4/19 255 142 0 2
° ° ° 221 85 0.2
° ° II 345• 340 0.4
I’ 458 822 0.9
- 26

-------
TABLE i-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (m) Weight (gms) Hg (ppm)*
Middle Arm V. Perch 4/20 187 113 0.2
I’ ‘I 185 85 01
U 4/22 134 85 0.1
‘I I’ 4/26 180 85 0.2
191 85 0.1
Middle Arm Sauger 4/20 345 397 0.3
II ‘I 340 340 0.4
4/21 351 397 0.5
‘I ‘I U 330 340 0.4
Middle Arm No. Pike 4/20 576 1361 0.7
‘I 659 2211 0.5
I’ I’ 720 2948 1 0
I’ 895 5897 1.4
I’ 1 4/21 920 4876 1.5
582 1531 0 6
I’ 1 4/24 600 1758 0.5
4/26 867 5897 0 8
‘I 673 2296 1.1
U U I 752 3289 0.4
‘I 785 3856 1 0
‘I I’ 511 1021 0.3
Middle Arm C. Cat 4/20 370 567 0.3
‘I 420 794 04
U 339 454 0 3
1 320 340 0 3
I’ I’ 379 567 0 4
4/21 411 907 0 6
I’ I’ 350 482 0 5
‘I I’ 519 1758 0.8
I’ I’ 325 397 0 3
‘I 415 850 0.5
‘I 340 397 0 4
I’ I’ 415 907 0 6
‘I 4/22 346 510 0 4
‘I I’ 310 340 0.4
“ ‘I 276 227 0 1
I’ I’ 325 397 02
‘I 365 539 0.4
‘I U 4/25 570 1276 0.8
‘I I’ 341 454 03
U 375 567 0.4
Middle Arm B. Crappie 4/24 292 454 0.4
— 27 -

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TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Lenght (mm) Weight (gms) Hg (ppm)*
Middle Arm W.Bass 4/21 275 397 0.2
I’ 1 270 340 0.2
II “ 210 142 0.2
1 4/25 313 425 0 2
I’ 269 368 1.0
‘I 1 220 142 0 2
‘I 259 255 0 5
I’ I’ 1 210 113 0.2
I’ 212 142 03
U 4/26 268 170 0.5
Lower Arm No. Pike 4/22 680 1928 0.5
U ‘I 606 1644 0 3
I’ U I’ 580 1531 0 3
I’ U I’ 824 4649 2.3
I’ ‘I U 640 2155 0 4
U I’ 1 582 1418 0 4
‘I 1 627 1707 0.4
H U 4/26 961 5897 1.4
I’ 671 2438 0 4
‘I I’ ‘I 588 1361 0.2
‘I ‘I 1 699 2523 0.8
‘I ‘I “ 582 1616 0.4
Lower Arm Walleye 4/22 531 1814 0.5
H I’ U 448 1162 0 7
U “ 374 539 03
11 ‘I 360 454 0.2
‘I 330 340 0.2
II ‘I 1 340 454 03
I’ I’ I’ 322 284 0 2
.11 304 284 02
U “ 562 2155 0.5
° I’ 316 368 0 3
I’ 318 397 0 3
I’ ° 435 992 08
° I’ 392 680 0 3
345 425 0 2
I’ ‘I 342 397 03
‘I I’ ‘I 278 227 0.2
Lower Arm C. Cat 4/22 370 624 0.5
H ° 412 737 0 4
I’ 335 397 0.2
380 684 0.3
- 28 -

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TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Lenght (mm) Weight (gms) Hg (ppm)*
Lower Arm C. Cat 4/22 334 397 0.2
I’ 1 358 539 03
I’ 369 595 0 7
‘I 1 392 680 0 4
I’ 466 1332 0.3
Lower Arm V. Perch 4/22 244 255 0.2
193 113 01
‘I 4/26 186 85 0.2
Lower Arm Sauger 4/22 313 255 0.3
II II 4/26 338 340 0 3
I’ 266 170 03
U ‘I 260 142 0.1
Tail Race C. Cat 4/16 458 950 0.3
410 690 <0 1
351 440 0.1
I’ U 340 330 <0.1
U I’ 570 2250 0 7
361 450 0 3
I’ 0 491 1250 <0 1
II UI I I 372 490 0.3
II II II 358 410 0.2
‘I 404 590 0.5
‘I I’ 385 560 0.3
Tail Race Walleye 4/16 375 567 0.2
H ‘I 458 992 0 2
330 340 0 2
‘I 345 454 0.4
I’ 365 567 <0.1
‘I 345 397 0 1
I’ H 471 1134 0 4
‘I 4/25 481 1304 <0 1
‘I 352 400 <0 1
‘I 351 425 0 4
I’ 351 425
351 454 0 1
‘I 439 1 021 <0 1
I I 315 284 <01
0 I’ 352 397 0.6
I’ 1 415 879 0.2
- 29 -

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TABLE I-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Lenght (mm) Weight (gms) Hg (ppm)*
Tailrace Sauger 4/25 332 368 0.2
I’ 343 340 <0 1
I’ “ 1 283 170 0.1
Tailrace W. Bass 4/25 299 482 0.2
Whitlocks Walleye 4/17 390 684 0.5
‘I 1 390 567 0.2
U 1 360 482 0 2
‘I ‘I 368 510 0.3
I’ U 1 395 680 0 3
‘I 366 510 07
‘I ‘I U 425 850 0.2
° ° 335 454 0 2
4/18 421 850 0.6
0 352 482 01
353 482 04
330 368 0.4
414 794 0.3
361 510 0.2
339 397 04
340 397 0.3
Whitlocks No. Pike 4/18 550 1304 0.3
4/20 590 1729 0.3
590 1729 0 4
560 1361 0 2
600 1701 0 3
570 1361 0 2
590 1446 0 3
660 1928 0.4
590 1616 02
610 1871 0 3
570 1361 0.3
‘I 525 1134 0.7
Whitlocks C. Cat 4/18 410 765 0.5
Whitlocks W. Bass 4/17 222 113 0.1
“ 4/18 308 510 0.5
234 170 0.2
1 4/20 350 907 1 .2
II ° 200 142 0.1
- 30 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (m) Weight (gms) Hg (ppm)*
Whitlocks Sauger 4/18 342 425 0.2
‘I 1 333 284 0 5
I’ 313 227 0.2
I’ ‘I 337 312 0.3
‘I 4/20 350 340 0.2
Whitlocks V. Perch 4/17 200 0.113 0.1
‘I 1 180 0.142 0 2
‘I 1 1 238 0.142 0.1
Upper Arm No. Pike 5/17 700 2495 1.35
‘I U ‘I 930 4990 1 38
° ° 647 1814 0.95
° ° 664 2268 0.48
° ° 755 2977 1 .57
° ° 540 1077 0 30
° ° 570 1307 0.41
Upper Arm Walleye 5/17 395 850 0.43
° 370 624 0.40
° ° 365 567 0 22
° “ 380 624 0.48
° 400 737 0.27
° ° ° 460 1134 0.43
“ ° 400 737 0.29
° ° 335 454 0.95
450 964 0.75
0 432 794 0 95
II u ° 480 1162 0 68
429 907 0 55
° ° ° 421 709 0.84
° ° 416 794 0 50
II 375 595 0 54
° ° 422 822 0.34
Upper Arm C.Cat 5/17 440 1134 0.55
454 1361 0.65
389 709 0 31
II UI II 450 1049 0 58
310 397 0 27
400 850 0 15
340 567 0 48
285 284 0 31
° ° 320 454 0.62
250 198 0 23
365 624 0.56
- 31

-------
TABLE 1A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Upper Arm C. Cat 5/17 335 539 0.31
I H H 285 312 0.39
340 539 0.22
‘I I 315 397 0.40
I’ H 260 227 0.60
II 240 227 0.21
Upper Arm Sauger 5/17 270 142 0.29
1 5/19 305 227 0.28
465 680 0.98
H 1 290 198 0 36
U U 285 170 0 19
‘I “ 435 284 0 56
‘I 260 113 0.44
‘I 285 198 0.21
Upper Arm W. Bass 5/17 220 170 0.30
U 205 142 0 10
‘I H I’ 200 113 0.26
° “ ° 210 170 0.06
° 319 964 0 62
° ° 325 567 0 68
° ° ° 294 454 0.66
° ° ° 316 567 0.60
° ° ° 283 397 0 43
° ° 306 510 0 31
H 305 454 0 75
° ° 260 312 0 23
° ° ° 275 312 0.60
° 280 340 0 42
° “ 315 510 0 73
° ° ° 264 284 0.49
242 227 0.67
° ° 305 510 0 40
279 368 0.45
Upper Arm W. Crappie 5/17 315 510 0.74
° ° ° 325 567 1.02
Middle Arm N. Pike 5/20 695 2438 1.49
° ° 590 1418 0.61
1040 8278 0 81
730 2438 0.89
1090 8392 1 .07
II II ° 745 3204 1.09
° 640 1588 0.38
- 32 -

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TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Middle Arm N. Pike 5/22 590 1474 0.25
‘I U 1 800 3600 0.58
I’ I’ 605 1474 0.33
‘I 527 1219 0.26
II 795 1474 0.80
Middle Arm Walleye 5/20 425 737 0.42
U I II II 295 227 0.32
I’ 450 964 0.39
‘I 320 340 0.32
‘I ‘I 395 624 0.48
‘I U I’ 332 397 0.35
I’ “ 195 255 0.55
U 332 312 0.19
U I’ 320 340 0.11
H U 300 284 0.18
I’ 450 964 0.33
‘I U 295 255 0.26
I’ I’ 340 454 0 33
‘I 359 454 0.20
° ° 290 255 0.30
° 330 284 0.30
Middle Arm C. Cat 5/20 250 482 0.21
U 305 340 0 11
5/21 344 425 0 45
° ° 420 822 0 38
352 454 0 31
° ° 5/22 481 1474 0 32
° 365 539 0.31
Middle Arm Sauger 5/21 375 454 0.40
Middle Arm W. Crappie 5/20 329 567 0.90
I’ 5/21 320 510 0.24
° B. Crappie 5/20 319 567 0.23
I’ 290 397 0 56
° U 5/21 275 255 0.70
° 5/22 290 255 0 76
° ° 303 454 1.12
Middle Arm W. Bass 5/22 272 312 0.45
° ° ° 277 340 0 28
I’ 314 454 0 23
U 306 397 0.62
- 33

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TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Lower Arm N. Pike 5/20 640 1616 0.50
I’ 700 2608 0 54
I’ “ 550 1304 0.24
II H 605 1474 0.30
° ° 5/21 542 1247 0.21
II 5/22 736 2466 0.53
Lower Arm Walleye 5/20 450 1021 0.25
450 1021 0.35
340 454 0.52
° ° ° 365 482 0.21
° ° ° 369 652 0.45
° ° 312 312 0 18
° ° 339 425 0 26
° ° ° 359 510 0.32
It 342 425 0.18
° ° 302 312 0 38
° 305 312 0.21
° ° 413 709 0 22
° ° 273 198 0 18
280 227 0.19
309 340 0.24
Lower Arm C. Cat 5/20 385 539 0.19
5/21 320 454 0 21
340 454 0 30
318 340 0.25
Lower Arm V. Perch 5/20 180 85 0.14
176 85 025
175 85 025
5/21 210 113 0.24
Lower Arm Sauger 5/21 250 113 0.28
280 170 0 31
5/22 335 368 0.32
Lower Arm W. Crappie 5/20 360 794 0.58
I’ 5/22 350 680 0.52
302 368 0.54
B. Crappie 315 482 0.64
305 425 0 81
300 425 0.25
Tail Race Walleye 5/19 355 510 0.32
1 310 284 0 30
295 284 0.16
- 34 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Tail Race Walleye 5/19 281 227 0.12
I’ 368 510 0.06
‘ I 325 397 0.21
I’ ‘S 455 1134 0.23
1 308 255 0 20
U “ 310 284 0.45
I’ “ 292 284 0.06
I I I I 290 227 0.12
“ H 280 255 0 12
310 283 0.04
‘ I 310 340 0.79
“ U H 321 340 0 17
“ ‘ I 330 312 0.20
Tail Race Sauger 5/19 430 794 0.20
Tail Race C. Cat 5/19 285 227 0.23
I’ “ 335 454 0.24
“ “ ‘ I 430 1021 0.54
“ ‘ I I’ 350 454 0.48
I’ U 288 227 0.17
I I SI “ 350 454 0 36
‘I “ 390 680 0 12
630 3572 0.45
I’ “ 510 1588 0.24
1 1 350 284 0 16
380 567 0.35
‘ I “ 360 510 0 25
‘ I “ 450 964 0.21
II “ 335 397 0 20
435 1021 0.28
355 510 0 07
1 ‘S 455 1077 0 12
II II 470 1247 0.34
‘ I 335 397 0 25
310 340 0.26
Whitlocks Walleye 5/17 445 794 0.21
‘ I 535 1588 0 26
I’ 1 370 425 0 38
357 425 0 67
354 369 0.18
I “ 457 879 0.18
439 737 0 25
‘S 321 340 0 25
347 397 0.15
— 35 —

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Whitlocks Walleye 5/17 420 737 0.30
I’ 345 397 0 13
I’ 471 1162 0.32
I’ ‘1 I’ 310 312 0.12
‘I U 319 369 0 23
U 1 339 454 0 35
‘I 321 340 0.28
Whitlocks N. Pike 5/17 610 1786 0.24
I’ I’ 590 1389 0.25
U 631 1928 0 30
‘I U 600 1474 0.42
‘I H 610 1588 0 32
I’ “ 580 1 389 0 21
‘I 760 2948 0 35
‘I 1 578 1361 0 25
I’ 600 1673 0 20
° ° U 665 2098 0.41
II U UI
Whitlocks C. Cat 5/17 320 397 0.32
U U 410 822 0 25
UI II II 390 680 0 21
328 454 0.21
U 458 794 0 33
U I 314 340 0 32
° ‘I 5/18 318 368 0 12
‘I U 323 340 0.30
Whitlocks W. Bass 5/17 280 397 0.52
II 300 454 0.33
294 454 0 65
° 340 680 0 29
‘I ° 315 454 0 33
“ ° 326 198 0.30
203 113 0.18
Whitlocks Sauger 5/17 312 227 0.33
° 310 198 0 44
285 198 0 40
5/18 440 850 0.51
U ‘I 422 652 0 40
‘I 335 340 0.47
Whitlocks B. Crappie 5/17 300 482 0.60
U ° 295 454 0 45
300 454 0.60
- 36 —

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms H _ g (ppm)*
Whitlocks B. Crappie 5/17 318 595 0.62
‘I 295 454 0.80
‘I ‘I 1 291 454 0 71
U 285 454 0.20
I’ 310 539 0.52
II ‘I 290 454 0.18
° ° 304 510 0.72
Whitlocks V. Perch 5/17 180 85 0.21
° 188 85 0.11
° ° 181 85 0.18
Upper Arm Walleye 6/21 389 623 0.62
214 284 0.38
° ° ° 449 879 0.87
° ° ° 374 567 0.56
° ° 386 567 0 46
II ° 379 595 0.50
° ° 276 198 0.40
299 255 0.39
345 454 0.67
346 397 0.74
418 822 0.54
362 454 0.78
320 340 0 45
414 765 0.70
292 227 0.38
470 1049 0.87
Upper Arm C. Cat 6/21 351 454 0.40
II ° 399 652 0.49
333 425 0 28
309 340 0.20
342 454 0.27
II II 350 454 0.28
330 397 0.31
393 680 0.32
400 822 0 37
386 765 0 24
378 538 0 32
342 454 0 40
“ ° “ 342 482 0.39
295 255 0.54
290 255 0.15
394 595 0.20
300 284 0.20
485 680 0.31
475 595 0.55
- 37 -

-------
TABLE 1.-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) j g (ppm)*
Upper Arm V. Perch 6/21 225 142 0.30
Upper Arm W. Bass 6/22 294 368 0.45
‘I ‘I U 304 368 1.08
I’ I’ 332 482 0.79
‘I 287 368 0.50
I’ ‘I 282 340 0.62
‘I I 291 340 0.55
‘I ‘I 270 284 0 42
I’ 275 340 0.82
H 290 368 0.95
I’ ‘I 281 340 0.87
‘I I’ 255 255 0.35
6/23 280 368 0 37
‘I I’ U 255 284 0.18
‘I 279 368 0.33
‘I I’ 280 368 0 63
U H 11 245 255 0 10
1 271 340 0 90
I’ U 294 425 0 53
‘I 284 397 0.24
1 215 170 0.21
Upper Arm Sauger 6/21 232 255 0.50
I’ 392 482 0 55
H 6/22 408 567 0.79
II UI II 340 284 0.38
U 332 284 0 50
I’ I’ 255 113 0.37
H I’ U 232 85 0.23
Upper Arm W. Crappie 6/21 207 113 0.24
II II U 213 142 0 27
‘I ‘I 325 482 0 90
I’ ‘I 211 142 0.14
B. Crappie “ 175 85 0.12
Middle Arm Walleye 6/25 485 1134 0.65
I’ 360 454 0 35
‘I 315 255 0.25
H ‘I 342 425 0 32
‘I I’ 360 454 0 23
‘I 490 595 0 36
‘I 315 255 0 30
U I’ 380 482 0.55
I’ 322 340 0.26
I’ 342 368 0.43
- 38 -

-------
TABLE1A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) H (ppm)*
Middle Arm Walleye 6/25 475 1021 0.50
H I U 358 454 0.24
I’ 360 454 0.34
‘I 1 330 284 0.88
U I 357 425 0.40
‘I 439 850 0.35
Middle Arm C. Cat 6/25 370 595 0.29
I’ H U 304 340 0.13
U 412 907 0.19
‘I “ 358 482 0.20
H 340 454 0.21
U 1 471 1247 0.42
‘I U 277 255 0.18
U U 278 284 0.20
U 320 368 0.09
I’ I’ 309 340 0.22
U I’ 450 1219 0 08
H 328 284 0.14
‘I 438 680 0.30
‘I 340 454 0.23
U H 533 2013 0 18
U U 290 340 0.08
I’ U 252 198 0.21
‘I 1 280 255 0 24
I’ 325 454 0.11
‘I 1 321 368 0.19
Middle Arm N. Pike 6/25 728 2722 0.80
Middle Arm W. Bass 6/25 290 340 0.50
I’ 310 454 0 60
I’ 300 340 0.29
H 272 340 0 52
I’ 223 142 0.26
U U 228 142 0.10
H 1 285 368 0 37
I’ 6/26 300 425 0 29
I’ 1 293 397 0 28
U 305 425 0.50
Middle Arm V. Perch 6/25 221 142 0.41
U P1 223 142 0.18
Middle Arm Sauger 6/25 418 680 0.39
I’ 300 227 0.58
- 39

-------
TABLE;1 Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (m) Weight (gms) Hg (ppm)*
Middle Arm Sauger 6/25 348 368 0.30
II I I 318 312 1.00
H 232 113 0.07
I’ 6/26 320 227 0.47
Middle Arm W. Crappie 6/25 203 113 0.10
‘ I 224 142 0.07
Lower Arm Walleye 6/25 500 1304 0.43
‘ I 323 340 0.32
I’ I’ 380 567 0.24
SI I’ 380 567 0.63
‘ I 429 737 0.30
H H 343 340 0.24
U 358 454 0.30
H 290 227 0.15
410 567 0.40
I’ 365 482 0.10
U U 0 344 454 0.29
U U 455 964 0.25
II 342 425 0.33
1 446 992 0.40
U U 405 680 0.29
U U 396 652 0.13
Lower Arm C. Cat 6/25 372 680 0.19
U U 420 907 0.30
412 794 0.24
U 402 680 0.35
U 310 340 0.23
‘ I U 359 567 0.42
432 907 0.32
U H 322 397 0.24
6/26 300 340 0.20
U 335 454 0 25
• U 329 397 0.20
323 397 0 25
U 1 U 420 850 0 71
U II 334 454 0.13
422 907 0.29
372 680 0 22
326 397 0.32
U 1 417 850 0.54
240 454 0 25
U 0 330 454 0.20
Lower Arm W. Bass 6/25 289 340 0.45
U 282 340 0.48
- 40 -

-------
TABLE 1-A
Length (m), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
318
296
269
276
264
482
454
340
340
284
0.54
0.40
0.24
0.43
0.23
Date Length (mm )
II
II
II
U
II
II
Weight (gm Hg (ppm)*
Area
Lower
Arm
— Fish
W. Bass
6/25
II
II
U
6/26
6/27
Lower
Arm
W. Crappie
6/25
165
85
0.18
I’
I
314
425
0.68
‘I
I
•6/26
183
85
0.06
°
“
‘I
202
85
0 08
‘I
U
6/27
200
113
0.13
U
B. Crappie
6/26
246
225
0.20
Lower
Arm
Sauger
6/26
279
170
0.13
‘I
H
424
482
0.62
Tail
Race
Walleye
6/27
250
142
0.18
‘I
I
u
260
170
0.17
°
U
I
270
170
0.18
‘I
I
U
345
425
0.08
‘I
fi
H
314
312
0.19
I’
I
300
255
0 15
‘I
I
290
255
0.47
“
“
6/28
277
227
0 26
‘I
1
257
194
0 15
U
I
319
340
0 30
“
“
I’
280
227
0.33
U
I
543
1928
0 33
“
“
“
253
142
0.22
‘I
I
275
227
0.51
U
.
I
1
283
227
0.30
“
I’
I
322
312
0.17
Tail
Race
C. Cat
6/27
353
454
0.20
‘I
1
375
538
0 14
I’
1
I
380
567
0 22
‘I
492
1814
0 07
“
“
I’
295
283
0,18
“
‘I
285
227
0.13
“
“
H
332
397
0.16
“
“
1
360
510
0 31
‘I
11
301
283
0 21
U
U
U
340
397
0.09
U
“
323
340
0.18
‘I
1
6/28
370
567
0.15
‘I
“
321
454
0.17
“
U
H
- 41 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (m) Weight (gms) Ijg (ppm)*
Tail Race C. Cat 6/28 412 737 0.44
U U 345 194 0.30
Tail Race V. Perch 6/27 180 85 0.16
Whitlocks Walleye 6/21 418 709 0.20
‘I 400 684 0.42
U 345 425 0.51
U I’ 314 284 0 24
H I’ 335 368 0 26
II I’ 330 340 0.45
I’ “ 310 255 0 40
U U 525 1559 0 31
° ° 348 425 0.72
° ° 352 482 0.36
° 260 170 0.33
461 1021 0.32
° U 291 255 0.20
° 456 907 0 34
II ° ° 293 255 0 13
° ° 347 425 0.25
Whitlocks N. Pike 6/22 705 3090 0.70
° ° 6/23 390 454 0.22
Whitlocks C. Cat 6/21 400 737 0.43
° ° 400 794 0.52
° I’ 368 680 0.52
° 405 907 0 36
° ° 6/22 264 255 0 18
299 284 0.13
410 794 0.65
390 680 0.50
° ° ° 390 709 0.49
° ° 370 765 0 50
275 255 0.32
° 348 425 0.30
6/23 370 567 0.23
° ° 276 227 0 14
IS ° 361 567 0 29
° ° 318 425 0.25
Whitlocks W. Bass 6/22 299 425 0.37
II ° ° 321 510 0 54
° 219 142 0 20
° ° 309 425 0.14
- 42 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Whitlocks W. Bass 6/22 208 142 0.32
U U 203 113 0 21
II II 100 113 0 12
‘I 200 142 0.19
Whitlocks Sauger 6/21 380 454 0.76
‘I U 368 425 0 83
1 423 539 0.35
I’ U 330 284 0.48
I’ U 431 737 0.60
U U U 345 284 0.38
° 6/22 322 255 0 18
° ° 224 85 0.49
11 6/23 365 454 0.22
° ° 311 227 0 21
° ° I’ 210 113 0 14
308 198 0.36
Whitlocks B. Crappie 6/21 296 454 0.99
220 170 0 48
° 260 284 0 25
° ° ° 280 397 0 52
230 198 0 10
300 340 0 38
° ° ° 310 482 0 81
° I’ 290 425 112
° ° 6/22 215 170 0 18
° ° 6/23 330 454 0.70
W. Crappie 6/21 215 142 0.10
180 85 0.18
186 85 017
6/22 197 85 0 29
6/23 235 170 0 18
240 198 0.10
Whitlocks V. Perch 6/21 180 85 0.38
° 180 57 0.36
6/23 240 198 0.18
220 198 0.11
- 43 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (ppm)*
Upper Arm Walleye 9/20 405 907 0.3
‘I 1 H 424 709 0.7
U 373 539 08
U 383 425 0 3
H 335 368 1.7
H “ 300 227 0 3
° 295 255 0.3
258 170 0.2
9/21 294 255 0.3
° ° ° 365 539 0.5
° ° 324 340 0.3
° ° ° 390 567 0.7
° ‘I 369 567 0.6
° 332 397 02
° ° 229 284 0 2
“ ° ° 428 907 0.6
Upper Arm N. Pike 9/20 737 2495 2.01
Upper Arm C. Cat 9/20 360 510 0.2
° ° 532 1673 1 .2
9/21 347 482 0.2
332 454 0.2
9/22 395 709 0.3
° ° ° 400 709 02
° ° ° 336 454 0.3
394 595 0.6
318 340 0.2
II
Upper Arm V. Perch 9/20 192 113 0.3
- ° 9/22 189 113 0 1
158 57 <0.1
Upper Arm W. Bass 9/20 248 227 0.2
260 284 0 5
291 425 0 3
9/21 295 454 1 0
255 284 0.5
244 227 1 2
° ° ° 295 397 0 4
° 9/22 296 454 0 4
299 454 0.9
300 482 0.9
Upper Arm Sauger 9/20 236 113 0.1
- 44 -

-------
TABLE 1-A Length (m), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (pp)*
Middle Arm Walleye 9/25 368 454 0.4
U ‘I 244 113 0.2
H U 0 330 312 0 2
460 879 0.5
I’ ‘I 304 227 0.2
‘I U 417 684 0.5
I’ I’ 323 340 0 2
‘I 434 652 0.7
I’ 323 340 0.27
259 198 0.21
I’ 358 425 0.48
° 385 539 0.40
I’ 439 737 0.40
“ 410 652 0.3
II ° ° 384 510 0.2
Middle Arm N. Pike 9/26 600 1361 0.46
Middle Arm C. Cat 9/25 305 312 0.3
288 255 03
300 284 0 1
° ° ‘ H’ 425 822 0 3
“ 355 482 02
II I’ 381 567 0 2
437 907 0.4
“ “ 294 227 0.2
“ 9/26 355 454 0.3
“ 619 850 0 5
“ “ 365 454 0.1
341 425 0.3
“ “ “ 354 454 0.2
“ ‘I 324 368 0.3
“ 9/27 375 567 0.3
“ 375 567 0.3
289 227 0.2
“ 295 255 0.3
Middle Arm W. Bass 9/25 265 340 0.7
297 425 0 2
215 170 07
295 425 1 0
“ 280 368 09
“ “ 9/27 205 142 0.2
Middle Arm V. Perch 9/25 180 85 <0.1
“ “ “ 180 85 <0.1
“ “ 9/26 210 113 0.1
1 92 11 3 <0. 1
“ “ 9/27 190 113 <0.1
- 4c -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (pp)*
Lower Arm Walleye 9/25 332 340 0.2
I’ I’ 320 312 0.2
II I I 365 454 0.4
1 270 170 01
I’ 292 227 0.3
I’ I’ U 344 425 0.2
‘I U 374 454 0 2
271 198 0.2
U I’ 338 340 0.1
I’ U 285 227 <0.1
SI I’ 408 567 0.2
I’ U II 405 652 0 2
II II 345 454 0 3
U 486 1191 0.3
Lower Arm C. Cat 9/25 352 482 0.2
II 1 II 300 284 0 3
II U 9/26 334 454 0 3
SI II II 373 539 0.3
II U II 344 425 0.4
9/27 382 567 0.2
Lower Arm W. Bass 9/25 218 198 0.2
II I I II 281 425 0 4
U 15 318 482 06
I I I I 310 482 06
I I I 314 482 0 8
55 II II 320 482 0 7
U 315 454 06
U U 230 198 02
U I I 305 425 08
II U 304 482 0.9
U II 9/26 307 454 0.7
U U U 313 454 08
U 55 U 314 510 1.0
1 U I I 310 510 0.7
323 567 0 8
II SI 9/27 321 482 0 8
U 55 286 368 0.8
U 55 310 425 08
II II 55 318 539 09
II 55 248 284 0.7
Lower Arm N. Pike 9/25 660 1588 0.31
621 1446 0.37
Lower Arm Sauger 9/26 307 255 0.2
- 46 -

-------
.TABLE i-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (pp)*
Tail Race Walieye 9/19 338 397 .0.1
‘I ‘I 1 345 454 <0.1
‘I U 324 340 <0 1
‘I 325 340 <0.1
‘I 1 425 794 03
U “ I’ 324 368 0 2
I’ “ 350 425 0 1
‘I I’ 305 227 0 1
290 284 <0.1
‘I 230 368 0.1
I’ ‘I 332 397 0.1
334 368 0.1
U 305 312 0.1
I’ I’ 1 302 255 <0.1
‘I U 320 397 0.1
‘I ‘I 1 254 170 <0.1
Tail Race C. Cat 9/19 330 368 <0.1
° 305 340 01
I’ 270 227 <0 1
° 250 198 <0 1
I’ ° 1 230 142 0 1
° U U 270 227 <0 1
° ° U 240 170 01
° ° ° 230 142 <0 1
° ° ° 242 142 0 1
II II II 239 142 <0 1
280 255 0 1
° ° ° 242 142 0 2
250 142 02
° 205 113 01
U “ I’ 260 1 98 <0 1
242 142 <0 1
° ° ° 290 255 0.4
° ° ° 250 170 <0 1
° • 252 142 0.1
° “ 250 198 <0.1
Tail Race W. Bass 9/19 330 652 0.1
Whitlocks Walleye 9/21 230 113 0.1
307 284 0.2
° ° ° 378 510 03
° ° 295 255 0 2
U ° 236 113 0.1
U ° ° 270 170 0.2
303 284 0.2
- 47 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (pp)*
Whitlocks Walleye 9/21 238 113 <0.1
I’ ‘I 288 255 <0.1
I’ 319 255 0.2
‘I U 379 510 0.2
I’ ‘I H 370 482 0.1
‘I 490 1049 0.2
‘I H I 317 284 0.1
‘I ‘I 333 368 0 2
I’ 313 284 0.1
Whitlocks N. Pike 9/21 488 794 0.18
‘I “ I’ 413 510 0 21
‘I 9/22 660 1843 0.32
Whitlocks C. Cat 9/22 322 425 0.3
U 300 340 0.1
U 278 227 0.1
‘I U 420 737 0.2
‘I I’ 305 284 0.1
I’ I’ 371 454 0.3
‘I 374 567 0.2
I’ I’ U 392 595 0.2
U 1 308 312 0.2
Whitlocks W. Bass 9/20 314 537 0.7
‘I 315 454 0.7
I’ I’ 253 255 0.2
9/21 290 454 0.3
“ I’ 250 284 0.2
‘I I’ 9/22 244 255 0.2
‘I U 390 794 0.8
Whitlocks Sauger 9/20 243 113 <0.1
9/21 365 368 0.2
I’ ‘I I 420 567 0 4
‘I I’ 276 170 0.1
U U 1 335 284 02
I’ I’ U 347 340 0 4
306 227 0.3
H U 1 271 142 <0.1
I’ I’ U 250 113 <0 1
U 301 227 <0.1
I’ ‘I I 256 142 0 1
I’ 1 9/22 320 312 0.2
‘I 215 85 <0.1
- 4R -

-------
TABLE 1 A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (pp)*
Whitlocks V. Perch 9/21 201 113 0.1
H 0 0 224 170 <0 1
I’ 196 113 0 1
9/22 193 113 <0 1
H 216 170 0 1
‘I 164 113 <0 1
1 235 170 02
I’ I’ I 190 113 0 1
‘I 190 113 0 1
II II 194 113 <0.1
“ ‘I 205 113 01
182 85 01
182 85 0.1
I’ 1 203 113 0.1
‘I 187 85 <0.1
‘I 207 113 <0.1
Whitlocks B. Crappie 9/20 317 537 0.6
‘I 9/21 298 482 0.3
I’ W. Crappie 9/20 218 170 <0.1
9/21 243 255 <0.1
E. Swim Walleye April 419 794 0.29
330 822 0.22
267 227 0.22
I’ 317 368 0 18
I’ I’ 546 1616 0 31
‘I ‘I 317 340 0 20
1 254 170 0.21
E. Swim N. Pike April 521 765 0.23
I’ 1 571 936 0.23
‘I ‘I 597 1418 0 30
648 1758 0 30
“ 1 571 1191 0.27
II II II 571 1247 0.29
E. Swim B. Crappie April 305 510 0.22
0 0 241 340 0 14
IS 0 254 340 0 19
‘I 1 254 284 0 20
254 284 0 17
“ I’ 229 227 0.12
I’ I’ 190 142 0.11
E. Swim V. Perch April 254 198 0.27
241 227 0.22
- 49 -

-------
TABLE 1-A Length (rn) , weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date ength (mm) Weight (gms) Hg (pp)*
E. Swim V. Perch April 216 198 0.32
241 170 0.30
E. Swim W. Crappie May 254 312 0.19
‘I I’ 317 624 0.27
U “ U 267 340 0.24
1 272 368 0.20
‘I “ H 254 312 0.17
I’ I’ 221 255 0.18
B. Crappie “ 234 227 0.16
H ‘I 254 255 0.17
‘I ‘I 267 340 0 20
‘I ‘I 272 368 0.17
E. Swim W. Bass May 387 1049 0.55
E. Swim N. Pike May 483 850 0.26
June -
E. Swim B. Crappie July 335 680 0.27
W. Crappie “ 254 284 0.16
‘I I’ H 241 255 0 19
I’ H 267 312 0 18
‘I I’ 241 227 0.20
E. Swim N. Pike July 462 680 0.21
E. Swim V. Perch July 178 85 0.30
157 57 0 20
U “ 178 85 018
H H 157 57 0.23
II I’ 157 57 0.19
II II H 178 85 0.15
I’ 152 85 018
ii ‘I 157 85 0.16
II II U 171 85 022
I’ 140 57 0.14
E. Swim Walleye July 330 368 0.23
E. Swim Crappie July 241 284 0.16
I’ U 267 312 0.19
I’ U 254 312 0.26
E. Swim V. Perch July 221 227 0.22
U ‘I U 241 284 0.21
- 50 -

-------
TABLE 1-A Length (mm), weight (grams), mercury content (ppm) and type
of fish caught during each sampling period, at each sampling
location. (continued)
Area Fish Date Length (mm) Weight (gms) Hg (pp)*
E. Swim V. Perch July 216 170 0.19
U U 216 170 0.30
‘I 203 170 0 18
° ° 216 142 0.22
E. Swim WaIleye Sept. 335 397 0.24
° ° 317 340 0.19
310 312 0.19
° ° ° 330 368 0.22
° ° 305 312 0.27
° ° ° 267 198 0.21
C, Swim Crappie Sept. 279 368 0.24
° ° 284 397 0.21
° ‘I 241 255 0.19
343 822 0 40
° ° 229 255 0 16
° ° “ 284 482 0 30
° ° ° 279 368 0 26
“ ° 259 340 0 17
248 284 0 16
267 340 0.19
E. Swim V. Perch Sept. 229 142 0.22
190 85 0.21
221 142 0 19
190 85 0 40
° 216 85 0.14
196 85 0.32
178 85 0 22
° ° 183 85 020
165 57 0.17
241 170 0.25
— 51 -

-------
TABLE 2A - Results of Statistical Analyses on Mercury Concentrations in
Fish Samples
Cheyenne - Upper Arm
Mean Mercury Total No. Standard 99% Confidence
Month Species Conc.(ppm) Sampled Deviation Max. Mm. limits of mean
April Walleye 0.8 15 0.4 1.4 0.3 0•5 1.0
May 0.5 16 0.2 0.9 0.2 0.4 0.7
June 0.6 16 0.2 0.9 0.4 0.5 0.7
Sept . 0.5 15 0.4 1.7 0.2 0.3 0.8
Total 0.6 62 0.3 1.7 0.2 0.5 0.7
April No. Pike 0.7 11 0.4 1.7 0.3 0.3 1.0
May 0.9 7 0.5 1.6 0.3 0.4 1.4
Sept . 2.0 1 0.0 2.0 2.0 2.0 2.0
Total 0.8 19 0.5 2.0 0.3 0.5 1.2
April C. Catfish 0.6 20 0.3 1.3 0.1 0.4 0.8
May 0.4 17 0.2 0.6 0.1 0.3 0.5
June 0.3 19 0.1 0.5 0.1 0.3 0.4
Sept . 0.4 9 0.3 1.2 0.2 0.1 0.7
Total 0.4 65 0.3 1.3 0.1 0.3 0.5
April W. Bass 0.5 20 0.3 1.2 0.2 0.4 0.7
May 0.5 19 0.2 0.7 0.1 0.3 0.6
June “ 0.5 20 0.3 1.1 0.1 0.4 0.7
Sept . “ 0.6 10 0.3 1.2 0.2 0.4 0.9
Total 0.5 69 0.3 1.2 0.1 0.4 0.6
April Sauger 0.3 10.0 0.2 0.9 0.1 0.1 0.5
May H 0.4 8.0 0.3 1.0 0.2 0.2 0.7
June H 0.5 7.0 0.2 0.8 0.2 0.3 0.6
Total 0.4 25.0 0.2 1.0 0.1 0.3 0.5
May Crappie 0.8 2.0 0.2 1.0 0.7 0.5 1.2
June “ 0.3 5.0 0.3 0.9 0.1 0.0 0.7
Tôtàl 0.5 7.0 0.4 1.0 0.1 0.1 0.8
April Yellow Perch 0.2 5.0 0.1 0.3 0.1 0.1 0.3
apt . “ 0.2 3.0 0.1 0.3 0.1 0.0 0.3
To i’1 0.2 8.0 0.1 0.3 0.1 0.1 0.2
GRAND TOTAL 0.5 255.0 0.3 2.0 0.1 0.5 0.6
— 52 —

-------
TABLE2A - Continued
Cheyenne - Middle Arm
Mean Mercury Total No. Standard 99% Confidence
Month Species Conc.(ppm) Sampled Deviation Max. Mm. limits of mean
April Walleye 0.6 16 0.3 1.4 0,3 0.4 0.7
May 0.3 16 0.1 0.5 0.1 0.2 0.4
June 0.4 16 0.2 0.9 0.2 0.3 0.5
Sept . 0.3 16 0.2 0.7 0.0 0.2 0.4
Total 0.4 64 0.2 1.4 0.0 0.3 0.5
April No. Pike 0.8 12 0.4 1.5 0.3 0.5 1.1
May 0.8 11 0.4 1.5 0.2 0.4 1.0
Total 0.8 23 0.4 1.5 0.2 0.6 1.0
April C. Catfish 0.4 20 0.2 0.8 0.1 0.3 0.5
May 0.3 7 0.1 0.4 0.1 0.2 0.4
June 0.2 20 0.1 0.4 0.1 0.1 0.2
Sept . 0.3 18 0.1 0.5 0.1 0.2 0.3
Total 0.3 65 0.2 0.8 0.1 0.2 0.3
April W. Bass 0.4 10 0.3 1.0 0.2 0.1 0.6
May 0.4 4 0.2 0.6 0.2 0.2 0.6
June 0.4 10 0.2 0.6 0.1 0.3 0.5
Sept . 0.6 6 0.3 1.0 0.2 0.3 1.0
Total 0.4 30 0.2 1.0 0.1 0.3 0.5
April Sauger 0.4 4 0.1 0.5 0.3 0.3 0.5
June 0.5 6 0.3 1.0 0.1 0.2 0.8
Total 0.4 10 0.2 1.0 0.1 0.3 0.6
May Crappie 0.6 7 0.3 1.1 0.2 0.3 1.0
June 0.1 2 0.0 0.1 0.1 0.1 0.1
Total 0.5 9 0.4 1.1 0.1 0.2 0.8
April Yellow Perch 0.1 5 0.1 0.2 0.1 0.1 0.2
June 0.3 2 0.1 0.4 0.2 0.1 0.6
Sept . 0.1 5 0.0 0.1 0.1 0.1 0.1
Total 0.2 12 0.1 0.4 0.1 0.1 0.2
GRAND TOTAL 0.4 213 0.3 1.5 0.0 0.4 0.4
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TABLE 2-A- continued
Cheyenne - Lower Arm
Mean Mercury Total No. Standard 99% Confidence
Month Species Conc.(ppm) Sampled Deviation Max. Mm. limits of mean
April Walleye 0.3 16 0.2 0.8 0.2 0.2 0.5
May 0.3 15 0.1 0.5 0.2 0.2 0.3
June 0.3 16 0.1 0.6 0.1 0.2 0.4
Sept . 0.2 16 0.1 0.4 0.0 0.1 0.3
Total 0.3 63 0.1 0.8 0.0 0.2 0.3
April No. Pike 0.6 12 0.6 2.3 0.2 0.2 1.1
May 0.4 3 0.2 0.5 0.2 0.1 0.7
Sept . “ 0.4 2 0.1 0.4 0.3 0.2 0.5
Total 0.6 17 0.5 2.3 0.2 0.2 0.9
April C. Catfish 0.4 9 0.2 0.7 0.2 0.2 0.5
May 0.2 3 0.1 0.3 0.2 0.2 0.3
June 0.3 20 0.1 0.7 0.1 0.2 0.4
Sept . 0.3 6 0.1 0.4 0.2 0.2 0.4
Total 0.3 38 0.1 0.7 0.1 0.2 0.3
June W. Bass 0.4 7 0.1 0.5 0.2 0.2 0.5
Sept . 0.7 20 0.2 1.0 0.2 0.6 0.8
Total 0.6 27 0.2 1.0 0.2 0.5 0.7
April Sauger 0.2 4 0.1 0.3 0.1 0.1 0.4
May 0.3 3 0.0 0.3 0.3 0.3 0.3
June 0.4 2 0.4 0.6 0.1 0.0 1.0
Sept . 0.1 2 0.1 0.2 0.0 0.0 0.4
Total 0.2 11 0.2 0.6 0.0 0.1 0.4
May Crappie 0.5 6 0.2 0.8 0.2 0.3 0.7
June 0.2 6 0.2 0.7 0.1 0.0 0.5
Total 0.4 12 0.3 0.8 0.1 0.2 0.6
April Yellow Perch 0.2 3 0.1 0.2 0.1 0.1 0.3
May 0.2 4 0.1 0.2 0.1 0.1 0.2
Total 0.2 7 0.1 0.2 0.1 0.1 0.2
GRAND TOTAL 0.4 175 0.3 2.3 0.0 0.3 0.4
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TABLE 2-A- continued
Whitlock Bay
Mean Mercury Total No. Standard 99% Confidence
Month Species Conc.(ppm) Sampled Deviation Max. Mm. limits of mean
April Walleye 0.3 16 0.2 0.7 0.1 0.2 0.4
May 0.2 16 0.2 0.7 0.1 0.2 0.3
June 0.3 16 0.1 0.7 0.1 0.2 0.4
Sept . 0.2 16 0.1 0.3 0.1 0.1 0.2
Total 0.3 64 0.2 0.7 0.1 0.2 0.3
April No. Pike 0.3 12 0.1 0.7 0.2 0.2 0.4
May 0.3 10 0.1 0.4 0.2 0.2 0.3
June “ 0.4 2 0.4 0.7 0.2 0.0 1.1
Sept . “ 0.2 3 0.1 0.3 0.2 0.2 0.3
Total 0.3 27 0.1 0.7 0.2 0.2 0.4
May C. Catfish 0.2 8 0.1 0.3 0.1 0.2 0.3
June 0.4 16 0.2 0.6 0.1 0.2 0.4
Sept . 0.2 9 0.1 0.3 0.1 0.1 0.3
Total 0.3 33 0.1 0.6 0.1 0.2 0.3
April W. Bass 0.4 5 0.5 1.2 0.1 0.0 1.0
May 0.4 7 0.1 0.6 0.2 0.2 0.5
June 0.2 8 0.1 0.5 0.1 0.1 0.4
Sept . U 0.4 7 0.3 0.8 0.2 0.2 0.7
Total 0.4 27 0.3 1.2 0.1 0.2 0.5
April Sauger 0.3 5 0.1 0.5 0.2 0.1 0.4
May 0.4 6 0.1 0.5 0.3 0.3 0.5
June 0.4 12 0.2 0.8 0.1 0.2 0.6
Sept . 0.2 13 0.1 0.4 0.1 0.1 0.3
Total 0.3 36 0.2 0.8 0.1 0.2 0.4
May Crappie 0.5 10 0.2 0.8 0.2 0.4 0.7
June 0.4 16 0.3 1.1 0.1 0.2 0.6
Sept . 0.3 4 0.2 0.6 0.1 0.0 0.6
Total 0,4 30 0.3 1.1 0.1 0.3 0.6
April Yellow Perch 0.1 3 0.1 0.2 0.1 0.1 0.2
May II 0.2 3 0.1 0.2 0.1 0.1 0.2
June 0.3 4 0.2 0.4 0.1 0.1 0.5
Sept . 0.1 15 0.1 0.2 0.1 0.1 0.1
Total 0.1 25 0.1 0.4 0.1 0.1 0.2
GRAND TOTAL 0.3 242 0.2 1.2 0.1 0.3 0.3
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TABLE 2-A- continued
Tailrace - Control
Mean Mercury Total No. Standard 99% Confidence
Month Species Conc.(ppm) Sampled Deviation Max. Mm. limits of mean
April Walleye 0.2 16 0.2 0.6 0.1 0.1 0.3
May 0.2 16 0.2 0.8 0.0 0.1 0.3
June 0.2 16 0.1 0.5 0.1 0.2 0.3
Sept . 0.1 16 0.1 0.3 0.1 0.1 0.2
Total 0.2 64 0.1 0.8 0.0 0.2 0.2
April C. Catfish 0.3 11 0.2 0.7 0.1 0.1 0.4
May “ 0.2 20 0.1 0.5 0.1 0.2 0.3
June 0.2 16 0.1 0.4 0.1 0.1 0.3
Sept . 0.1 20 0.1 0.4 0.1 0.1 0.2
Total 0.2 67 0.1 0.7 0.1 0.2 0.2
A ru Sauger 0.1 3 0.1 0.2 0.1 0.1 0.2
otal 0.1 3 0.1 0.2 0.1 0.1 0.2
GRAND TOTAL 0.2 134 0.1 0.8 0.0 0.2 0.2
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TABLE 2-A- continued
Lake Enemy Swim - Control
Mean Mercury Total No. Standard 99% Confidence
Month Species Conc.(ppm) Sampled Deviation Max. Mm. limits of mean
April Walleye 0.2 7 0.1 0.3 0.2 0.2 0.3
Sept . 0.2 0.1 0.3 0.2 0.2 0.3
Total 0.2 13 0.1 0.3 0.2 0.2 0.2
April No. Pike 0.3 6 0.1 0.3 0.2 0.2 0.3
‘ rotal 0.3 6 0.1 0.3 0.2 0.2 0.3
April Crappie 0.2 7 0.1 0.2 0.1 0.1 0.2
May 0.2 10 0.1 0.3 0.2 0.2 0.2
June 0.2 6 0.1 0.3 0.2 0.2 0.3
Sept . 0.2 10 0.1 0.4 0.2 0.2 0.3
Total 0.2 33 0.1 0.4 0.1 0.2 0.2
April Yellow Perch 0.3 4 0.1 0.3 0.2 0.2 0.3
June 0.2 16 0.1 0.3 0.1 0.2 0.2
Sept . 0.2 10 0.1 0.4 0.1 0.2 0.3
Total 0.2 30 0.1 0.4 0.1 0.2 0.2
GRAND TOTAL 0.2 82 0.1 0.4 0.1 0.2 0.2
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