600/ l
. 03 I
vyEPA
United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
EPA-600/3-80-038
March 1980
Research and Development
Protection Agency
Region 9
UN 1
Environmental
Effects of Western
Coal Surface Mining
Part V
Age and Growth of
Walleyes and
Saugers in the
Tongue River
Reservoir, Montana
1975-77
EJBD
ARCHIVE
EPA
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RESEARCH REPORTING SERIES
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This document is available to the public through the National Technical Informa-
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EPA-600/3-80-038
March 1980
2
ENVIRONMENTAL EFFECTS OF WESTERN COAL SURFACE MltiJtyM
PART V - AGE AND GROWTH OF WALLEYES AND SAUGERS IN THE
TONGUE RIVER RESERVOIR, MONTANA, 1975-77
by
Victor L. Riggs and Richard W. Gregory
Cooperative Fishery Research Unit
Montana State University
Bozeman, Montana 59717
Grant No0 R803950
Project Officer
Donald I. Mount
Environmental Research Laboratory
Duluth, Minnesota 55804
us EPA . Repository Material
SSS11" permanent Collection
> Mailcode 3404T
1301 Constitution Ave NW
Washington DC 20004
202-566-0556
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
DULUTH, MINNESOTA 55804
-------
DISCLAIMER
This report has been reviewed by the Environmental Research Laboratory-
Duluth, U.S. Environmental Protection Agency, and approved for publication.
Approval does not signify that the contents necessarily reflect the views
and policies of the U.S. Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement or
recommendation for use.
ii
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FOREWORD
As additional surface mining for coal in Western U.S. occurs, the
potential disruption of surface waters or their degradation is of increasing
importance. This study was completed to identify discernible impacts on
walleye and sauger populations in southeastern Montana as a result of strip
mining of coal.
No measurable impacts were found although the dilution volume into
which the drainage emptied was relatively large. This study provides a
background against which future evaluations can be assessed.
J. David Yount
Deputy Director
m
-------
ABSTRACT
A study was conducted between 1975-1977 on the populations of walleye
(Stizostedion vitreum) and sauger (Stizostedion canadense) in the Tongue River
Reservoir, in southeastern Montana. The Tongue River Reservoir is the recipi-
ent of mine water effluents from the Decker Mine, the largest surface coal
mine in the western United States. The objective of the study was to deter-
mine possible impacts of the mine on the walleye and sauger populations in
the reservoir, and to provide data against which future comparisons can be
made. These species were chosen because they are two of the most important
game fishes in the reservoir.
The age and growth of 640 walleyes and 546 saugers were determined from
collections made in gill nets, trap nets, and by electrofishing. The 1973
sauger year class and the 1972 walleye year class dominated the catches
during the three years of the study. The movements of tagged fish in late
March and early April 1977 strongly suggested that walleyes spawned in the
Tongue River, upstream from the reservoir. The growth rates for both
species were excellent for a northern latitude reservoir, indicating no
noticeable effect by surface coal mine operations at the time of the study.
IV
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CONTENTS
Page
Foreword in
Abstract iv
Figures vi
Tables vii
Acknowledgments ix
I Introduction 1
II Conclusions 4
III Recommendations 5
IV Description of Study Area 6
V Materials and Methods 14
VI Results and Discussion 16
A. Sauger Population Characteristics 16
B. Walleye Population Characteristics 26
C. Movement of Tagged Walleyes 37
D. Tag Loss 43
E. Deviation from Lee's Phenomenon 43
VII Potential Impacts of Surface Coal Mining 45
References 51
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FIGURES
Number Page
1 Map of Montana showing location of study area 2
2 Study area, showing locations of present and proposed surface
coal mining areas 7
3 Discharge rates of the Tongue River near Decker, Montana 9
4 Water level elevations above sea level for the Tongue River
Reservoir 10
5 Water storage history of the Tongue River Reservoir 11
6 Length-scale relation of saugers from the Tongue River Reservoir . 18
7 Growth in length of saugers from the Tongue River Reservoir 21
8 Length-weight relation of saugers from the Tongue River Reservoir . 23
9 Growth in weight of saugers from the Tongue River Reservoir .... 25
10 Length-scale relation of walleyes from the Tongue River Reservoir . 28
11 Growth in length of walleyes from the Tongue River Reservoir ... 33
12 Growth curves for male and female walleyes collected in the Tongue
River Reservoir and Tongue River study areas in 1977 34
13 Length-weight relation of walleyes from the Tongue River
Reservoir 38
14 Growth in weight of walleyes from the Tongue River Reservoir ... 39
15 Tagging locations in the Tongue River Reservoir of five adult
male walleyes recaptured in the Tongue River 41
16 Recapture locations in the Tongue River Reservoir of six adult
male walleyes previously captured in the Tongue River 42
vi
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TABLES
Number
1 Morphometric data of the Tongue River Reservoir at spillway
elevation ............................. 8
2 Species of fishes present in the Tongue River Reservoir,
1975-1977 ............................. 13
3 Lengths and weights of saugers from the Tongue River Reservoir
in each age class at time of capture ............... 17
4 Back calculated lengths of saugers from the Tongue River
Reservoir, 1975-1977 ....................... 19
5 Calculated lengths of saugers of different ages from various
waters .............................. 22
6 Estimated weight- to- length relation for saugers from the Tongue
River Reservoir .......................... 24
7 Lengths and weights of walleyes from the Tongue River Reservoir
in each age class at time of capture ............... 27
8 Back calculated lengths of walleyes from the Tongue River
Reservoir, 1975-1977 ....................... 29
9 Back calculated lengths of male and female walleyes collected
from the Tongue River Reservoir, 1977 ............... 30
10 Back calculated lengths of male and female walleyes collected
from the Tongue River, 1977 .................... 31
11 Lengths and weights of young-of-the-year walleyes from the
Tongue River Reservoir, September 1976 .............. 35
12 Calculated lengths of walleyes of different ages from various
waters .............................. 36
13 Estimated weight- to- length relation for walleyes from the
Tongue River Reservoir ...................... 40
14 Averages and ranges of some chemical and physical parameters
of the Tongue River Reservoir, November 1975 to November 1976 ... 46
vii
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TABLES
Number Page
15 Average values of selected parameters measured in the Decker
Mine discharge water and in the Tongue River above and below
the mine discharge, June 1975 to November 1976 48
viii
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ACKNOWLEDGMENTS
The authors thank those who assisted in this study: Dalton E.
Burkhalter, who assisted in the computer analysis of data; Allen A. Elser
and the Montana Department of Fish and Game, who provided field assistance
and equipment; and Russell R. Penkal, Janet Amestoy, and Stephen Leathe,
who aided in the field work. The Decker Coal Company provided research
station facilities.
This research was funded in part by the Montana Department of Fish and
Game, and by the U.S. Environmental Protection Agency, Environmental Research
Laboratory - Duluth, Research Grant No. R803950, awarded to Natural Resource
Ecology Laboratory, Colorado State University, and Fisheries Bioassay
Laboratory, Montana State University.
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SECTION I
INTRODUCTION
The Tongue River watershed, including the Tongue River Reservoir, lies
in the Fort Union Coal Basin, an area that encompasses a large portion of
eastern Montana (Figure 1) as well as parts of northern Wyoming and western
North Dakota. The Fort Union Basin, and other coal deposits in the northern
Great Plains, contain nearly half of the nation's known coal reserves. To
meet the nation's growing energy demands, surface coal mining in the Fort
Union Basin is rapidly increasing.
The largest surface coal mine in the Tongue River area is the Decker
Mine, located on the southwest shore of the Tongue River Reservoir in east-
ern Montana, just north of the Wyoming border. The Decker Mine began opera-
tion in 1972, and is currently being expanded to the southeastern shore of
the Reservoir; permit application has been made for expansion northward
along the western shore. As the mine expands, and production increases, the
Decker Mine complex is projected to be the largest surface coal mine in the
world. In addition to the Decker Mine, other mines are located in the Tongue
River watershed, farther up river in Wyoming. Resource development plans
also call for construction of mine-mouth coal-fired power plants in that
same region.
Historically, water from the Tongue River has been used for agricultur-
al purposes and the raising of livestock. In 1939 an earthfill dam was com-
pleted on the Tongue River, forming a reservoir for flood control and irriga-
tion water storage. In recent years the reservoir has also become an
important recreation area.
The potential impacts from coal mining and proposed coal combustion
facilities on the Tongue River system are largely unknown. To provide a
basis for measuring that impact, a variety of studies have been undertaken
by the Montana Cooperative Fishery Research Unit, U.S. Fish and Wildlife
Service, on the present status of the aquatic biota of the river and reser-
voir. The research reported here is the result of a study conducted between
1975 and 1977 on the populations of walleye (Stizostedion vitreum) and
sauger (S. canadense) in the Tongue River Reservoir. These are two of the
most important sport fishes in the reservoir, and are highly sought by
fishermen because of their large size and the excellent quality and flavor
of their flesh. The immediate objective of the present research was to
study the populations, age and growth, and life histories of the walleyes
and saugers in the Reservoir, and to see what discernable impact, if any,
present coal mining operations might be having on these fishes. The longer
1
-------
I
I
s
^
M
Heleno
Bozeman i
N
Packer. . _jv
-Tongue River Reservoir
^71 Fort Union CooTRegion
Figure 1. Map of Montana showing location of study area.
-------
range objective is to provide information against which comparisons can be
made in the future as mining operations in the Tongue River watershed in-
crease.
Additional studies on the aquatic biota of the Tongue River and Reser-
voir will be reported separately. These include reports on the microbiolog-
ical community within the Decker Mine settling pond (Turbak et al. In press),
the limnology of the Tongue River Reservoir (Whalen 1979), and the distribu-
tion and behavior of smallmouth bass (Micropterus dolomieui) and largemouth
bass (M. salmoides) in the reservoir (Penkal and Gregory, in press). Infor-
mation from these and the present study will be of value in formulating
recommendations for institution of appropriate safeguards to protect aquatic
life as mining and combustion operations expand in this region of the coun-
try with relatively little water and a fragile environment.
-------
SECTION II
CONCLUSIONS
1. Growth of both the walleye and sauger In the Tongue River Reservoir was
excellent for a northern body of water. Characteristics of the popula-
tions were: (a) the greatest increment of growth in length for both
species occurred during the first year of life and the greatest weight
increment during the third year; (b) annulus formation of both species
occurred primarily in June; (c) saugers collected were up to seven
years old and walleyes up to 11 years; (d) female walleyes of all age
groups collected were significantly larger than males; (e) the 1972
walleye year class and the 1973 sauger year class were predominant
during the three years of this study, representing from 37 to 56 per-
cent and 29 to 45 percent of the catch, respectively; the 1973 walleye
year class was noticeably weak.
2. Tag and recapture studies demonstrated that some sexually mature wall-
eyes migrate from the reservoir into the Tongue River in the spring,
presumably to spawn. Male and female walleyes captured in the river
were slightly larger than fish of the same age class collected in the
reservoir. The tag and recapture studies did not yield sufficient data
for comparable conclusions for saugers. The significance of the river
as a spawning habitat and the resultant contribution to reservoir
populations of walleyes and saugers has not been determined.
3. Based on the data collected, there is no apparent evidence that the
presence of surface mining activities adjacent to the reservoir, or the
addition of the mine discharge water after mixing with the Tongue River
water source to the reservoir, is affecting the growth, reproduction,
survival, or movements of walleyes or saugers within the reservoir.
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SECTION III
RECOMMENDATIONS
Further monitoring of walleye and sauger populations in the Tongue
River and Reservoir and concurrent water chemistry studies will be necessary
to determine if increased mining activities and associated human population
increases adversely affect these fish populations.
Information that will be critical for determining potential effects
include: (a) the future trends in growth, abundance, distribution, and age
structure of sport fishes; (b) the influence of human population increases
on fishing pressure and sport fish harvest; (c) the importance of the Tongue
River as a spawning area; (d) the food and habitat requirements of each
species at various life stages; (e) water quality data, including nutrients,
temperature, salinity, and concentrations of trace metals, on the mine
discharges and the receiving waters; (f) data on trace metal accumulation in
fish tissues.
-------
SECTION IV
DESCRIPTION OF STUDY AREA
The Tongue River Reservoir (Figure 2) is located in Big Horn County in
southeastern Montana, 23 km north of Sheridan, Wyoming. It is the only
major impoundment on the Tongue River. The river originates on the eastern
slopes of the Big Horn Mountains of Wyoming and flows in a northeast direc-
tion for 105 river kilometers until reaching the reservoir. The drainage
area above the reservoir is 4584 km2 [U.S. Geological Survey (USGS) 1976].
The river continues for 271 km beyond the reservoir to its confluence with
the Yellowstone River at Miles City, Montana.
The reservoir was created for irrigation and flood control purposes,
and the earthfill dam (27.7 m high) was completed in 1939. At spillway
level (1043 m above sea level) the reservoir floods an area of about 1415 ha
(USGS and Montana Department of State Lands 1977). At storage capacity the
reservoir has a maximum length of 12.5 km, a maximum width of 1.4 km, and an
average depth of 6.1 m (Garrison et al. 1975). The surface area is 1277 ha,
the length of shoreline at spillway elevation is 60 km, and the shoreline
development index is 4.74 (Penkal 1977). The shoreline development index is
the ratio of the length of the shoreline to the length of the circumference
of a circle having the same area as the lake (Hutchinson 1957). The initial
storage capacity of the reservoir was estimated at about 8939 ha-m in May
1939 (Dendy and Champion 1973); by 1948, sedimentation had decreased the
capacity to about 8557 ha-m. Assuming similar rates of sedimentation, the
1975 capacity was estimated to be about 7398 ha-m (USGS and Montana Depart-
ment of State Lands 1977). Selected morphometric characteristics of the
Tongue River Reservoir are listed in Table 1.
Peak runoff in the river usually occurs during late May and early June,
but 1975 was an exceptional year; runoff persisted from early May to mid-
July (Figure 3). The high runoff in 1975, coupled with an extensive late
summer draw-down, resulted in a reservoir fluctuation of about 8 m (Figure
4). Water levels in 1976 and 1977, when fluctuations were 5 m and 6 m, were
closer to normal. The greater water level fluctuation in 1975 is apparent
from the water storage history of the reservoir (Figure 5). Annual water
level fluctuations prevent the development of shoreline and emergent vegeta-
tion.
The river study section was approximately 3.1 river kilometers long and
contained areas of gravel substrate which appeared suitable for walleye and
sauger spawning. During the study period the ice cover broke up on April
23, 1975; April 3, 1976; and April 6, 1977.
-------
TONGUE RIVER
RESERVOIR
Figure 2. Study area, showing locations of present and proposed surface
coal mining areas. [Numbers designate water sampling stations
of Whalen (1979) discussed in section VII]
-------
TABLE 1. MORPHOMETRIC DATA OF THE TONGUE RIVER RESERVOIR AT SPILLWAY
ELEVATION (1043 m ABOVE SEA LEVEL).
Maximum depth (m)-7 18.0
Mean depth (m)-7 6.1
Depth of outlet (m)-7 15.2
Maximum length (km)-7 12.5
Maximum breadth (km)-7 1.4
Mean breadth (km)-7 1.1
Surface area (ha)-7 1277
Volume (ha-m)-7 7398
Length of shoreline (km)- 60
Index for shoreline development- 4.74
^Garrison et aL 1975.
-7USGS and Montana Department of State Lands 1977.
-7Penkal 1977.
8
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25
20
15
o
o
o
uu
O 10-
Of. lvr
O
1975
1976
1977
JAN FEB MAR APR MAY JUN JUL AUO SEP OCT NOV DEC
MONTH
Figure 3. Discharge rates of the Tongue River near Decker, Montana (USGS
1976, 1977, and 1978).
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1O44
1043
1042
1041
1O4Oi
< 1039-
103&
1037
1036
103&
JAN" FEB MAR ' APR ' MAY JUN " JUL ' AUG SEP OCT ' NOV DEC
MONTH
Figure 4. Water level elevations above sea level for the Tongue River Reservoir.
(Montana Department of Natural Resources, unpublished data)
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O
O
O
O
<
oc
O
1956 57 58 59 *> 61 62 63 04 «5 60 67 68 09 70 71 77 73 74 75 70 77
YEAR
Figure 5. vtoter storage history of the Tongue River Reservoir.
(Montana Department of Natural Resources, unpublished data).
11
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A warmwater fisheries program was implemented at the reservoir in 1963.
Prior to this time, rainbow trout (Salmo gairdneri) had been planted, but
their numbers remained low, and populations of rough fish, remaining from a
rehabilitation project in 1957, increased. The warmwater species planted
included northern pike (Esox lucius), channel catfish (Ictalurus punctatus),
largemouth bass (Micropterus salmoides) and walleye. White crappie (Pomoxis
annularis) and black crappie (Pomoxis"nigromaculatus) were present prior to
the 1957 rehabilitation and were abundant at the time of our study (Penkal
1977). Smallmouth bass (Micropterus dolomieui) first appeared in 1972 and
are believed to have entered the reservoir as a result of overflow from
stripmine ponds near Sheridan, Wyoming (Elser 1975). Saugers first appeared
in the reservoir in 1973 and are believed to stem from a planting by the
Wyoming Game and Fish Department in the Tongue River near the Montana-
Wyoming border in 1967 (Elser et al. 1977). Walleye fry were planted as
follows: 1965750,000; 1966100,000; 1967197,700; 1968601,200; and
196992,500. Of the warmwater fishes present in the reservoir, only
northern pike are not self-sustaining. A list of the species present is
given in Table 2.
12
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TABLE 2. SPECIES OF FISHES PRESENT IN THE TONGUE RIVER RESERVOIR,
1975-1977
Common name
Scientific name
Trouts
Rainbow trout
Brown trout
Minnows and carps
Carp
Goldfish
Golden shiner
Flathead chub
Suckers
River carpsucker
Shorthead redhorse
Longnose sucker
White sucker
Catfishes
Black bullhead
Yellow bullhead
Channel catfish
Stonecat
Sunfishes
Rock bass
Green sunfish
Pumpkinseed
Smallmouth bass
Largemouth bass
White crappie
Black crappie
Pikes
Northern pike
Perches
Yellow perch
Sauger
Walleye
Salmonidae
Sal mo gairdneri
S. trutta
Cyprinidae
Cyprinus carpio
Carassius auratus
NotemigoTius crysoleucas
Hybopsis gracilis
Catostomidae
Carpi odes carpio
Moxostonii macrolepidotum
Catostomus catostomus
C. commersoivf
Ictaluridae
Ictalurus melas
I.
1.
natal is
_ punctatus
Noturus flavus
Centrarchidae
Ambloplites rupestris
Lepomis cyanellus
L. gibbosus
Micropterus dolomieui
M. salmoides
Pomoxis annularis
£. nigromaculatus
Esocidae
Esox lucius
Percidae
Perca flavescens
Stizostedion canadense
S. vitreum
13
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SECTION V
MATERIALS AND METHODS
Walleyes and saugers were captured at numerous locations throughout the
reservoir with trap nets and gill nets in 1975, 1976, and 1977. The fishes
were widely distributed, and at any location on any given occasion no more
than 20 individuals were captured; most frequently the numbers were five or
less. During September 1976 electrofishing proved successful for collecting
young-of-the-year walleyes and 2- and 3-year-old saugers. In addition,
fishes were sampled in the river study section during spring 1977 by elec-
trofishing. Electrofishing was conducted in the reservoir at night and in
the river during the day. Direct current was used in both waters. The
shocking gear consisted of a modified Smith Root Model VI electrofishing
boat (Penkal 1977), a model VP-10 Coffelt variable voltage pulsator, and a
230-volt, 4000-watt, AC generator. Total lengths were measured to the
nearest millimeter and weights to the nearest 10 grams. Fish were tagged
with Floy FD-67 anchor tags in 1975 and 1976, and Floy FD-68B anchor tags in
1977. A right pelvic clip was used in 1976 and a left pelvic clip in 1977
as a precaution in the event of tag loss. Sex was determined by manually
expressing eggs or milt from ripe fish or by dissection.
Scale samples for age and growth determination were taken from the
fish's left side, just posterior to the pectoral fin. Cellulose acetate
impressions were examined with a scale projector at a magnification of 66X.
Total scale radius and radius at each annul us were measured from the center
of the focus to the median anterior margin. The anterior edge of the scale
was considered the annulua for the period January 1 until the beginning of
spring growth.
The length-scale radius relations for walleyes and saugers in the
Tongue River Reservoir is curvilinear. The equation best describing this
relation is:
L = aSb
or log L = log a + b log S
where L = length, S = scale radius, and a and b are constants determined by
linear regression, using logarithms of the length and scale radius values.
The method of back calculation is that described by Hile (1941).
Weights were estimated by using the relation described by the equation
of Ricker (1975):
14
-------
W= aLb
or log W = log a + b log L
where W = weight, L = length, and a and b are constants determined by linear
regression based on logarithms of the length and weight values.
A modified Schnabel population estimate (formula 3.17 in Ricker 1975)
was computed for walleyes in the river study section for spring 1977.
A comparison of the ratio of tagged fish to untagged fin-clipped fish
in the population at the time of capture to the same ratio at the time of
recapture was used to determine tag loss. Statistical analyses were con-
ducted according to procedures described in Snedecor and Cochran (1967).
Linear regressions were derived using the method of least squares.
15
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SECTION VI
RESULTS AND DISCUSSION
A. SAUCER POPULATION CHARACTERISTICS
Age and growth
The growth rate of saugers varied considerably (Table 3). In some
age groups certain individuals were over 50% longer and 200% heavier
than others. Some fish reached 457 mm at age 3, while others not until
age 7.
The 1973 sauger year class was dominant in the three collection
years, making up 29.1% of the catch in 1975, 27.4% in 1976, and 43.8%
in 1977. The ages of saugers collected ranged from one to seven; only
two age 7 fish were taken. The largest sauger taken was 591 mm long
and weighed 2660 g. The largest sauger ever reported from the Tongue
River Reservoir weighed 3266 g; it was taken by an angler in 1975 and
was still the state record in 1977.
Annul us formation
Annul us formation occurred during June in 1975 and 1976. In 1975
it was 67% complete by June 19 and complete by July 11. In 1976 it was
80% complete on June 29 and complete by July 5. Nelson (1969) reported
that in saugers 3 years old and older in Lewis and Clark Lake, South
Dakota, annuli began forming in mid-June and were complete by early
July; Carlander (1950) reported May and early-June as the time of
annul us formation in saugers from Lake of the Woods, Minnesota.
Growth in length
The relation between body length and scale radius (Figure 6) was
based on 546 saugers, 141 to 631 mm long. The assumption was made that
no significant differences existed in the relation from one year to the
next, and therefore the data for all three years were combined.
The average back calculated lengths at each age increased when
calculations were made from progressively older fish (Table 4). This
observation is unlike Lee's phenomenon, where the average calculated
length at each age class usually decreases when the calculations are
made from progressively older fish.
16
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TABLE 3. LENGTHS AND WEIGHTS OF SAUGERS FROM THE TONGUE RIVER RESERVOIR
IN EACH AGE CLASS AT TIME OF CAPTURE
Age
class
1
2
3
4
5
1
2
3
4
5
6
7
1
2
3
4
5
6
7
Total
Number
6
23
17
12
21
6
101
107
76
65
37
1
0
0
4
32
26
10
1
length
Mean
215
315
423
481
537
258
305
387
462
501
547
613
--
378
453
495
536
587
(mm)
Range
1975
141-265
265-404
362-464
420-540
458-631
1976
197-293
216-365
293-578
347-530
427-591
465-595
1977
327-425
394-562
404-527
449-587
Number
5
15
15
8
12
6
100
107
76
65
37
1
0
0
4
32
26
10
1
Weight
Mean
88
277
677
915
1352
135
216
473
860
1163
1497
2100
--
435
797
1104
1443
1610
(g)
Range
60- 120
140- 560
400- 870
600-1150
1020-1750
60- 180
50- 440
170-1870
350-1350
720-2660
862-2210
--
300- 530
394-1040
840-1240
740-1900
17
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7001
600
100 200 300 400 5OO
SCALE RADIUS (MM)X66
Figure 6. Length-scale relation of saugers from the Tongue River
Reservoir.
18
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TABLE 4. BACK CALCULATED LENGTHS OF SAUGERS FROM THE TONGUE RIVER
RESERVOIR, 1975-1977
Age Num^er
group f.sh
1 12
2 124
3 129
4 120
5 112
6 47
7 2
Grand average
calculated length
Grand average
incremental length
Sum of grand
average increments
Total length at the end of
1
146
164
175
186
194
195
156
180
180
180
2
270
310
324
330
337
340
311
130
310
345
372
400 445
409 460 496
421 479 518
429 495 546
396 457 503
73 50 37
383 433 470
each year
6 7
541
573 591
543 591
23 18
493 511
19
-------
Growth curves for saugers, based on the grand average calculated
lengths and on the sums of the grand average increments of length,
differed (Figure 7); this difference can be attributed to the greater
calculated lengths of the older fish. The summation of the grand
average increments is probably the most representative of the growth of
saugers because it avoids the irregularities caused by the successive
elimination of fish of the older age groups. This curve should repre-
sent the average growth that saugers might have if the opposite effect
of Lee's phenomenon were not present. The rationale for this data
treatment is discussed in a later section. The greatest average annual
increment for saugers occurred during the first year of life and de-
creased steadily thereafter.
The back calculated lengths of the saugers from the Tongue River
Reservoir are greater than those reported for other Montana waters
(Table 5). The only exception is the 1948 Fort Peck Reservoir study
(Peters 1964) in which average lengths equaled those at age 6, and
surpassed those at age 7 in the present study. Saugers grew faster in
the Tongue River Reservoir than in the Garrison Reservoir, North
Dakota, Lake Winnebago, Wisconsin, and Lake of the Woods, Minnesota,
except that the length of saugers at age 6 in the Garrison Reservoir
surpassed that of saugers in all other studies. The lengths of saugers
from Lewis and Clark Lake were greater than those in the present study,
and the lengths of saugers from Lake Oahe were greater at all ages
except age 1.
Growth in weight
A length-weight relationship (Figure 8) was derived from the
measurement of 521 saugers captured from 1975 through 1977. In the
length-weight relationship formula (W = aL ), the constant b equals 3.0
if growth is isometric (Ricker 1975). When b is greater or less than
3.0, growth is allometric. Values greater than 3.0 indicate weight
increasing faster than the length and values less than 3.0 indicate
length increasing faster than weight. In a normal fish population b
usually ranges between 2.5 and 4.0 (LeCren 1951). The value of b for
the Tongue River Reservoir sauger (b = 3.23) falls within this range,
and indicates allometric growth.
The predicted weights of fish at ages 1 through 7 were obtained by
applying the length-weight equation to the summed grand average incre-
ments at successive annuli (Table 6, Figure 9). Although the greatest
annual length increment occurred during the first year of life, the
greatest annual weight increment did not occur until age 3. The
average weight increment was nearly constant for ages 2 through 5 but
declined at ages 6 and 7.
20
-------
600-1
GRAND AVERAGE
CALCULATED LENGTHS
GRAND AVERAGE SUMMED
INCREMENTS
AVERAGE ANNUAL INCREMENTS
34567
YEAR OF LIFE
Figure 7. Growth in length of saugers from the Tongue River Reservoir.
21
-------
TABLE 5. CALCULATED LENGTHS OF SAUCERS OF DIFFERENT AGES FROM VARIOUS WATERS
ro
ro
Local i ty
Tongue River Reserv.
(present study)
Ft. Peck Reserv. , MT ,
1948 (Peters 1964)-'
Ft. Peck Reserv. , MTa/
1949 (Peters 1964)-'
Marias River, MT /
1961 (Peters 1964)^'
Garrison Reserv. , ND
(Carufel 1963)-7
Lake Winnebago, WI
(Priegal 1969)-7
Lake of the Woods, MN
Number
of fish
546
124
134
16
%«b/
m-
222 f^7
784 m
957 f
883
Average calculated total lengths at end of year (mm)
1
180
130
122
112
122
127
125
135
126
2
310
224
244
203
216
224
241
252
185
3
383
297
325
282
292
318
307
310
235
4
433
363
389
335
358
399
335
338
276
5
470
429
371
384
447
467
356
358
313
6789
493 511
493 521
488
465
587
376 389 401
378 391 401
337 362 359 385
10
383
(Carlander 1950)-
Lewis and Clark Lake
(Nelson 1969)
Lake Oahe, ND, SD
(Nelson 1974)
1112
506
188 324 404 466 514 560 596 626
158 311 401 464 517 551 589 594 612
- Total length in inches converted to total length in mm.
- m = male, f = female.
- Standard length in inches converted to total length in mm (Total length - Standard length ratio of
1.159 derived by Carlander 1950).
-------
35001
30OO-
25OO-
2OOO-
X
o
1500-
1OOO-
5OO-
w =
r =
.00000203 L
.942
3.2317
1OO 2O 0 3OO 4OO 5OO 6OO 7OO
TOTAL LENGTH (MM)
Figure 8. Length-weight relation of saugers from the Tongue River
Reservoir.
23
-------
TABLE 6. ESTIMATED WEIGHT-TO-LENGTH RELATION FOR SAUCERS FROM THE TONGUE RIVER RESERVOIR
(LENGTH IN MILLIMETERS, WEIGHT IN GRAMS)
ro
Length
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
Weight
0.0
0.0
0.0
0.0
0.1
0.1
0.2
0.3
0.4
0.6
0.9
1.1
1.5
1.9
2.3
2.9
3.5
4.2
5.0
5.9
6.9
8.0
9.3
10.6
12.1
13.8
15.6
17.5
Length
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
220
225
230
235
240
245
250
255
260
265
270
275
280
Weight
19.6
21.9
24.3
27.0
29.8
32.8
36.0
39.4
43.1
47.0
51.1
55.4
60.0
64.9
70.0
75.4
81.1
87.1
93.4
99.9
107
114
122
129
138
146
115
165
Length
285
290
295
300
305
310
315
320
325
330
335
340
345
350
355
360
365
370
375
380
385
390
395
400
405
410
415
420
Weight
174
184
195
206
217
229
241
253
266
280
294
308
323
338
354
371
387
405
423
441
460
471
500
521
542
564
587
610
Length
425
430
435
440
445
450
455
460
465
470
475
480
485
490
495
500
505
510
515
520
525
530
535
540
545
550
555
560
Weight
634
658
683
709
735
762
790
818
847
877
908
939
971
1000
1040
1070
1110
1140
1180
1220
1250
1290
1330
1370
1420
1460
1500
1550
Length
565
570
575
580
585
590
595
600
605
610
615
620
625
630
635
640
645
650
655
660
665
670
675
680
685
690
695
700
Weight
1590
1640
1680
1730
1780
1830
1880
1930
1980
2040
2090
2150
2200
2260
2320
2380
2440
2500
2560
2630
2690
2760
2830
2890
2960
3030
3110
3180
-------
125O
1OOO
CD 730-
O
UJ
5OO-
25O
3 4
YEAR OF LIFE
Figure 9. Growth in weight of saugers from the Tongue River Reservoir.
(Dashed line represents average annual weight increments).
25
-------
B. WALLEYE POPULATION CHARACTERISTICS
Age and growth
The growth rates of individual walleyes varied considerably (Table 7).
For example, certain individuals in the 1973 age-3 group were over 100%
longer and 280% heavier than others of the same group. Some individuals
reached 457 mm during their third year of life and others not until their
fifth year.
The 1972 walleye year class dominated the catch in the three years of
the study; it constituted 56% of the catch in the reservoir in 1975, 37% in
1976, and 52% in 1977. Of the walleyes captured in the river study area
during the spring spawning migration of 1977, the 1972 year class was also
dominant (37% of the catch). The 1973 year class was noticeably weak; its
greatest contribution was in 1976 when it represented 11% of the reservoir
catch. It contributed only 5% to the reservoir catch in 1975 and 2% in
1977, and none were collected in the river in 1977.
During the study age-0 to -11 walleyes were collected, but age groups
7-11 were poorly represented. No walleyes under age 3 were collected in
1977. The largest walleye captured was 787 mm in length and weighed 5556 g.
Annul us formation
Annul us formation in 1976 was 22% complete by June 9 and complete by
June 20. Too few walleyes were collected in May and June of 1975 to deter-
mine time of annul us formation, and no fish were collected after May in
1977.
Growth in length
Measurements of 640 walleyes 173 to 787 mm long were used to derive the
length scale relationship (Figure 10). This relation was applied to the
combined data for the years 1975, 1976, and 1977, and to the reservoir
male-female groups and the river male-female groups for 1977.
The tendency for greater average calculated lengths at younger ages
when calculated from older fish is evident in the back calculated lengths
from the combined walleye data (Table 8). This trend breaks down with the
inclusion of the 10- and 11-year-old fish; however, each of these age groups
are represented by only one individual. The presence or absence of the
trend is difficult to determine when considering the back calculated lengths
for the reservoir and river male-female data (Tables 9 and 10). The age
groups 1-4 are either poorly represented or not represented at all in the
1977 male and female samples, and it is in these age classes where the trend
was most evident.
26
-------
TABLE 7. LENGTHS AND WEIGHTS OF WALLEYES FROM THE TONGUE RIVER RESERVOIR
IN EACH AGE CLASS AT TIME OF'CAPTURE
Age
class
I
2
3
4
5
6
7
0
1
2
3
4
5
6
7
8
9
10
11
1
2
3
4
~
5
6
V
7
/
8
9
1
2
3
4
5
6
7
8
9
10
Total length (mm)
Number
20
7
84
31
7
5
4
64
9
60
27
93
36
12
6
4
4
__
1
--
25
3
80
30
5
7
4
5
28
9
18
9
6
1
Mean
267
355
431
485
572
584
646
190
215
327
443
490
539
589
632
682
735
--
787
408
479
525
555
616
658
704
385
510
569
589
625
669
640
Range
1975
231-317
300-430
317-500
422-629
542-601
502-665
612-709
1976
159-216
173-313
194-412
386-507
411-578
445-615
531-635
582-704
604-891
700-762
--
1977-Reservoir
362-440
475-484
398-595
477-621
593-657
590-699
661-751
1977-River
319-415
415-575
530-604
560-632
595-675
610-755
~
Weight (g)
Number
19
7
70
27
7
5
4
64
9
60
25
90
35
12
5
4
4
"~ *~
1
--
25
3
80
30
5
7
4
--
5
28
9
18
9
6
1
Mean
173
396
783
1147
1919
2050
2709
59
101
320
817
1139
1508
2051
2306
2645
4608
5556
--
724
1010
1433
1730
2306
2687
3928
--
682
1286
1707
1969
2442
3058
2680
Range
90- 300
300- 600
340-1260
700-2980
1580-2410
1360-3280
1542-3760
30- 90
40- 300
130- 500
400-1380
550-2080
880-2630
1360-3050
1640-3100
2240-3720
3690-5556
--
""
--
420-1740
930-1130
680-2080
1070-2600
2090-2790
1890-3290
2480-5330
490- 720
840-2070
1350-2020
1570-2750
2170-3100
2360-4090
27
-------
7001
600
soo
4OO
o
z
<
o
300-
2OO-
1OO
100 200 3dO 400
SCALE RADIUS (MM)X66
Figure 10. Length-scale relation of walleyes from the Tongue River
Reservoir.
28
-------
TABLE 8. BACK CALCULATED LENGTHS OF WALLEYES FROM THE TONGUE RIVER
RESERVOIR, 1975-1977
Age
class
Number
of fish
Total length at the end of each year
8
10 11
1
2
3
4
5
6
7
8
9
10
11
29
67
141
127
151
56
33
20
14
1
1
213
231 304
242 336 406
246 352 430 479
256 366 445 493 525
257 376 457 509 542 558
263 393 476 534 566 598 606
258 391 484 540 583 604 631 647
259 399 482 557 603 637 662 679 694
219 346 434 497 534 578 599 622 628 640
260 378 453 530 587 641 673 706 733 754 771
Grand average
calculated length 247 353 437 499 542 583 625 661 692 697 771
Grand average
incremental length 247 102 77 51
34 24 17 18 15 17 16
Sum of grand
average increments 247 349 426 477 511 535 552 570 585 602 618
29
-------
TABLE 9. BACK CALCULATED LENGTHS OF MALE AND FEMALE WALLEYES COLLECTED
FROM THE TONGUE RIVER RESERVOIR, 1977
Age Number
class of fish
1
2
3
4
5
6
7
8
9
Grand average
calculated
Grand average
incremental
0
0
0
0
5
4
3
0
35
27
17
8
3
1
2
1
2
2
length
length
Sum of grand
average increments
Sex
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
Total length
1
--
247
267
249
252
266
260
257
268
263
239
310
237
263
253
266
253
266
253
266
2
329
347
375
355
378
363
375
397
399
382
441
375
405
359
378
106
112
359
378
3
329
413
440
433
461
440
453
480
493
463
549
444
494
435
459
76
82
435
459
at the end
4
479
479
514
490
507
529
556
520
610
515
581
487
520
49
56
484
515
5
505
553
520
543
566
597
551
651
569
631
516
559
29
39
513
554
of each year (mm)
6
542
565
594
627
527
671
606
680
553
598
24
27
537
581
7
609
657
601
688
631
707
613
690
20
26
557
606
8
615
699
651
725
633
717
17
16
574
622
9
665
743
665
743
13
17
587
639
30
-------
TABLE 10. BACK CALCULATED LENGTHS OF MALE AND FEMALE WALLEYES COLLECTED
FROM THE TONGUE RIVER, 1977
Age
class
1
2
3
4
5
6
7
8
9
10
Number
of fish
0
0
0
0
5
0
0
0
25
3
9
0
17
1
8
1
4
2
1
n
Sex
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
F
M
c
Total
1
_ _
--
__
--
250
--
__
--
251
256
268
269
270
260
272
242
279
219
2
__
323
--
__
--
358
380
393
391
406
394
405
396
409
346
length at
3
385
--
__
--
440
454
476
471
498
477
521
465
501
434
4
480
521
520
524
551
517
579
525
574
497
the end of each year (mm)
5 6 7 8 9 10
504
558
550 569
550 571 585
582 609 629
565 586 606 621
609 633 648 660
562 593 613 633 644
637 665 686 702 714
642 578 599 622 628 640
Grand average
M
calculated length F
Grand average M
incremental length F
Sum of grand M
average increments F
258 374 454 505 535 576 595 625 641 640
267 396 483 549 591 643 662 688 714
258 117 80 46 29 22 17 17 10
267 129 88 66 43 27 19 15 12
12
258 374 454 500 529 551 568 585 595 607
267 396 483 549 591 618 638 652 664
31
-------
The general growth curve for walleyes derived from the grand average
calculated lengths differs greatly from that derived from the summed incre-
ments of length (Figure 11). The summed increments of length are believed
to be more representative of the growth of walleyes because of the occur-
rence of a reverse Lee's phenomenon in the back calculated lengths. The
greatest annual length increments occurred at age 1 and then decreased to a
nearly constant level at ages 7 through 11.
Separate growth curves based on the summed increments of length for
male and female walleyes collected in the reservoir and river in 1977
(Figure 12) showed the growth of females to be faster than that of males at
all ages. This relation has been reported by others (Mraz 1968; Stroud
1949; and Tucker and Taub 1970), but some investigators have shown the
opposite trend for 1- and 2-year-old walleyes (Lewis 1970, Nelson 1974, and
Wolfert 1977). At the end of the first year of life, females captured in
the reservoir had a 12-mm advantage over the males and by age 9 this advan-
tage had increased to 52 mm. For the river sample, the females had a 9-mm
advantage at age 1 which increased to 68 mm at age 9. The curve for females
from the river is based on only nine fish and may not be representative of
the females that spawn in the river.
The calculated lengths of walleyes of both sexes captured in the river
were greater than those captured in the reservoir. This difference never
exceeded 19 mm for males at any given age, or 38 mm for females.
Young-of-the-year
A total of 64 young-of-the-year walleyes were collected between Septem-
ber 1 and September 16, 1976 (Table 11). These fish averaged 190 mm in
length and ranged from 159 to 216 mm. Priegal (1970) reported lengths of
young-of-the-year walleyes on September 1 for the years 1959 through 1967 to
range from 83 to 148 mm in Lake Winnebago, Wisconsin. Young-of-the-year
walleyes from Oneida Lake, New York, ranged from 111 to 156 mm on September
1 for the years 1956 through 1961 (Forney 1966). Wolfert (1977) reported
average lengths of 185 mm at the end of August and 230 mm by the end of
September for young-of-the-year walleyes in western Lake Erie.
Lengths of walleyes from the Tongue River Reservoir were greater than
those reported for other Montana reservoirs with two exceptions: Hauser
Lake, in which lengths were greater at ages 3 and 4, and Nelson Reservoir,
in which lengths were greater at age 6 (Table 12). Walleyes from the Tongue
River Reservoir grow faster than walleyes from Lake of the Woods, Minnesota,
and Lake Gogebic, Michigan, but slower than walleyes from Norris Reservoir,
Tennessee, and Canton Reservoir, Oklahoma. Walleyes from Clear Lake, Iowa,
showed slower growth rates than walleyes from the Tongue River Reservoir at
ages 1 through 6, but faster at ages 7 through 11. Walleyes from Lake Oahe
were longer at all ages except age 1. An earlier spawning season and a
longer growing season are factors contributing to the better growth in the
Tennessee and Oklahoma reservoirs.
32
-------
7001
600J
GRAND AVERAGE SUMMED
INCREMENTS
CALCULATED LENGTHS /
AVERAGE ANNUAL INCREMENTS
"l 2 3 4 5 6 7 8 9 10 11
YEAR OF LIFE
Figure 11. Growth in length of walleyes from the Tongue River Reservoir.
33
-------
RIVER FEMALE
X
/ X" RIVER MALE
RESERVOIR FEMALE,.
X
RESERVOIR MALE
R VER FEMALE.-
RIVER MALE
^>
RESERVOIR MALE
RESERVOIR FEMALE
123456789 123456789
YEAR OF LIFE
Figure 12. Growth curves for male and female walleyes collected in the
Tongue River Reservoir and Tongue River study areas in 1977.
34
-------
TABLE 11. LENGTHS AND WEIGHTS OF YOUNG-OF-THE-YEAR WALLEYES FROM THE
TONGUE RIVER RESERVOIR, SEPTEMBER 1976
Date
1
2
4
10
12
13
14
15
16
Number
of fish
4
18
3
2
3
2
8
7
17
Average
length
171
178
177
196
198
202
198
195
198
Range of
lengths (mm)
159-184
168-190
169-189
193-199
196-201
199-204
179-216
189-201
180-209
Average
weight (g)
35
56
40
55
70
70
65
63
66
Range of
weights
30-50
30-70
30-50
50-60
60-70
60-80
50-90
60-70
60-80
Totals
64
190
159-216
59
30-90
35
-------
TABLE 12. CALCULATED LENGTHS OF WALLEYES OF DIFFERENT AGES FROM VARIOUS WATERS
o>
Locality
Tongue River Res.
(present study)
Nelson Res. , MT /
1959 (Peters 1964F/
Lake Oahe, ND, SD
(Nelson 1974)
Clear Lake, IA
(Car lander and./
Whitney 1961)*'
Lake of the Woods , MN
(Carlander 1945)5'
Morris Res. , TN
(Stroud 1949)^
Lake Gogeblc, MI,
(Esclweyer 1950 Fx
Canton Res. ,,OK
(Lewis 1970)*7
KUlen Res., MT .,
1960 (Peters 1964P/
Frenchman Res. , MR,
1958 (Peters 1964P'
Hauser Lake, MT ./
1961 (Peters 1964)2'
Number
of fish
640
71
757
3079
2898
1146
519
870
18
34
9
Average calculated total lengths at end of year
1
247
94
213
178
163
262
117
310
79
185
168
2
349
193
351
287
235
417
239
427
170
338
325
3
426
269
445
373
293
475
307
495
305
401
429
4
477
345
522
434
342
506
361
554
406
460
526
56789
511 535 552 570 585
470 650
569 603 633 678
480 526 559 605 643
378 424 464 507 549
528 533 561 633
401 437 457 478 495
607 650 704
447
450
(mm)
10 11
602 618
686 699
577 607
508
-'Total length 1n Inches converted to total length in millimeters.
b/Standard length 1n Inches converted to total length in millimeters, (Total length- standard length
~ ratio of 1.159 derived by Carlander 1945).
-------
Growth in weight
The walleye length-weight relation (Figure 13) is based on a combined
sample of 616 fish. The value of the constant b, from the length-weight
formula, is 3.16. This value indicates allometric growth, where the in-
crease in weight occurs faster than the increase in length and falls within
the range of normal values established by LeCren (1951).
The predicted weight at ages 1 through 11 were obtained by applying the
length-weight equation to the summed grand average increments of length at
annulus (Figure 14). The yearly weight increments increased until age 3,
declined steadily until age 7, and remained fairly constant thereafter.
The predicted weights for walleyes for each 5 mm length interval
listed in Table 13.
are
Population estimate in the Tongue River
A population estimate of male walleyes in the river study section was
made in spring 1977. Electrofishing in the river was conducted on March 26,
28, and 31, and April I and 4, 1977 to determine if walleyes and saugers
were spawning in the river. Increased river discharge and the accompanying
increase in turbidity made electrofishing impossible beyond April 4 and no
direct evidence of spawning could be obtained. On the five dates of elec-
trofishing two saugers and 86 walleyes were captured. Of the 86 walleyes,
80 were ripe males, 30 of which (38%) were recaptured during the sampling
period. This resulted in a male recapture rate of 37.5%. Using the Chapman
method of population estimation (Ricker 1975) it was determined that 129
male walleyes (95% confidence limits: 86-251) were present in or passing
through the river study section from March 26 to April 4. None of the six
females was recaptured.
C. MOVEMENT OF TAGGED WALLEYES
Movement data were obtained for 11 walleyes, all of which were males.
Four of these (No. 1-4 in Figure 15) captured in the reservoir in fall 1976
were recaptured in the river study area in spring 1977, 8.5 to 15 km from
the points of release. Another walleye (No. 5 in Figure 15) was captured in
the summer channel of the river in spring 1976 and recaptured in the river
study section in spring 1977.
Of the 80 male walleyes tagged in the river study area during spring
1977, six were later recaptured in the reservoir (Figure 16). Of these six,
three were recaptured twice and their movements from the first point of
recapture to the second point of recapture are indicated by arrows in the
figure.
37
-------
35OO1
W
r
.000003507 L
.945
3.1608
3OOO-
25OO-
2OOO-
x
o
1300
10OO-
50O-
1OO 2OO 3OO 4OO 5OO 6OO ZOO
TOTAL LENGTH (MM)
Figure 13. Length-weight relation of walleyes from the Tongue River
Reservoir.
38
-------
25OO-
2OOO-
O
13OO-
O
LU
1OOO
5OO
234 567 891O11
YEAR OF LIFE
Figure 14. Growth in weight of walleyes from the Tongue River Reservoir.
(Dashed line represents average annual weight increments.)
39
-------
TABLE 13. ESTIMATED WEIGHT-TO-LENGTH RELATION FOR WALLEYES FROM THE TONGUE RIVER RESERVOIR
(LENGTH IN MILLIMETERS, WEIGHT IN GRAMS)
Length
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
Weight
0.0
0.0
0.0
0.0
0.1
0.2
0.3
0.4
0.6
0.8
1.1
1.5
1.9
2.4
3.0
3.6
4.4
5.3
6.3
7.4
8.6
9.9
11.4
13.1
14.9
16.9
19.0
21.3
Length
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
220
225
230
235
240
245
250
255
260
265
270
275
280
Weight
23.8
26.5
29.4
32.5
35.8
39.3
43.1
47.1
51.4
55.9
50.7
65.8
71.1
76.7
82.7
88.9
95.4
102
110
117
125
133
142
151
160
170
180
191
Length
285
290
295
300
305
310
315
320
325
330
335
340
345
350
355
360
365
370
375
380
385
390
395
400
405
410
415
420
Weight
202
213
225
237
250
263
276
291
305
320
336
352
369
386
403
422
440
460
480
500
521
543
565
588
612
636
661
686
Length
425
430
435
440
445
450
455
460
465
470
475
480
485
490
495
500
505
510
515
520
525
530
535
540
545
550
555
560
Weight
712
739
767
795
824
854
884
915
947
979
1010
1050
1080
1120
1150
1190
1230
1270
1310
1350
1390
1430
1470
1520
1560
1610
1660
1700
Length
565
570
575
580
585
590
595
600
605
610
615
620
625
630
635
640
645
650
655
660
665
670
675
680
685
690
695
700
Weight
1750
1800
1850
1900
1960
2010
2060
2120
2180
2230
2290
2350
2410
2470
2530
2600
2660
2730
2800
2860
2930
3000
3070
3150
3220
3300
3370
3450
-------
Fish
No.
1
2
-
5
Date
Tagged
(1976)
10/21
11/5
11/6
10/28
4/10
Date
Recaptured
(1977)
3/28
3/28
4/1
4/4
4/4
N
Figure 15. Tagging locations in the Tongue River Reservoir of five adult
male walleyes recaptured in the Tongue River.
-.
-------
Fish
No.
1
:
3
4
5
6
Date
Tagged
(1977)
3/28
3/28
3/28
4/3
3/28
3/28
Date
Recaptured
(1977)
4/8, 4/13
4/13, 4/17
4/23
4/25, 4/29
4/26
4/26
-
Figure 16. Recapture locations in the Tongue River Reservoir of six
adult male walleyes previously captured in the Tongue
River. (Arrows indicate movement of fish recaptured
twice.)
-------
The tag return data suggest that walleyes in the reservoir may use the
Tongue River for spawning. However, the portion of the reservoir population
that uses the river and the extent of their upstream migration can be
determined only through further research.
Whether saugers in the reservoir use the river for spawning has yet to
be determined. Since only ripe males and spent females were collected it
appears that most saugers had spawned before the start of sampling on March
23, 1977.
D. TAG LOSS
During summer 1976, 168 saugers and 76 walleyes were tagged and
fin-clipped to measure the extent of tag loss. During spring 1977, 46
saugers and 184 walleyes were similarly marked. Floy FD-67 anchor tags
were used in 1976 and Floy FD-68B anchor tags in 1977. Tags in both
years were placed behind the spiny dorsal fin.
Tags were lost from one of four (25%) saugers recaptured during
the summer of 1976. No tag loss occurred for the six saugers tagged in
summer 1976 and recaptured in spring 1977, nor for the two saugers
recaptured in spring 1977.
Only one fin-clipped walleye was recaptured during 1976 and it had
retained its tag. However, of six walleyes recaptured in spring 1977,
four (67%) had lost tags. During spring 1977 only one of 55 walleyes
recaptured had lost its tag.
Much of the tag loss was attributable to the vinyl tubing slipping
off of the anchor portion of the tag. Use of the Floy FD-68B tag,
which incorporates a plastic bulb on the end of the anchor, reduced
this kind of tag loss.
E. DEVIATION FROM LEE'S PHENOMENON
The greater calculated lengths at younger ages, when successively
older fish were used in making growth calculations, is evident for both
walleyes and saugers in the Tongue River Reservoir. The presence of
this phenomenon could be caused by some naturally occurring factor, or
by sampling bias. If non-random sampling were the problem, one of two
conditions existed: (1) a sampling technique which would have a ten-
dency towards capturing the smaller fish in the younger age classes, or
(2) a tendency towards capturing the larger fish of the older age
classes. Because of the variety of sampling techniques used (gill
nets, trap nets, and electrofishing), non-random sampling is not a
likely explanation. When Carlander and Whitney (1961) reported a
similar occurrence in the back calculated lengths for walleyes in Clear
Lake, Iowa, they felt that missed annuli on a few of the older fish may
43
-------
have been responsible. It is possible that missed annuli contributed to the
occurrence of the phenomenon in walleyes and saugers in the Tongue River
Reservoir.
Selective mortality, bearing more heavily on the smaller fish of each
age class, thus leaving the larger fish of each successive age class to be
sampled for age and growth, would also explain the apparent decrease in
growth rates observed. Predation has been shown to be selective toward
slower-growing walleyes during the first year (Chevalier 1973), but such
predation before the first annuli formed would have no effect on the back
calculated lengths. The continuation of such size selective predation into
the second and later years of life may be possible (Ricker 1975), but it
probably does not continue throughout all of the age groups. When the
phenomenon was observed in the calculated lengths for walleyes in Canton
Reservoir, Oklahoma, Lewis (1970) believed that the growth reduction may
have reflected the stabilization of an increasing walleye population to the
pre-existing forage fish population. The oldest walleyes taken during the
Tongue River Reservoir study were age 11 and the oldest saugers were age 7.
Because the ages of these fishes date back to the earliest known existence
of the two species in the reservoir, the apparent decrease in growth rates
may have been a result of an increase in numbers of these two species,
thereby increasing inter- and intra-specific competition. If so, later
monitoring of these populations in the reservoir will be required for veri-
fication.
44
-------
SECTION VII
POTENTIAL IMPACTS OF SURFACE COAL MINING
Surface run-off water in the immediate vicinity of the Decker mine, and
subsurface water resulting from disturbing the aquifer, are collected within
the Mine in a sedimentation pond system. The sedimentation pond water is
reused for dust control and for irrigation onto reclaimed mine spoils; ex-
cess water is pumped onto the flood plain of the Tongue River at the upper
end of the Reservoir.
Turbak et al. (In Press) have studied the quality of the settling pond
water, including the heavy metals arsenic, cadmium, lead, mercury, and
selenium, and data are reported for the mine effluent water for five dates
from July 1976 to April 1977. Concentrations ranged from 1.1 to 1.9
ug/liter for arsenic and <1 to <5 for cadmium, both of these below the
criteria published by EPA (1977). Reported concentrations for lead were
<0.01 to <0.1 mg/liter and for selenium were <0.3 to 0.5 ng/liter. No
specific numerical criteria for these two metals have been provided by EPA
(1977), although it is recommended that acceptable concentrations be based
on 96-hr LC50 values for sensitive resident aquatic species. The reported
concentrations for mercury, 0.11 to 0.87 ug/liter, are in excess of the EPA
(1977) criterion of 0.05 ug/liter, however these criteria are for receiving
waters, not the discharge itself.
Additional data on mercury concentrations in the mine effluent between
October 1975 and August 1976 have been reported by Phillips (1978); based on
reported analyses performed by the Montana Department of Health and Environ-
mental Sciences, mercury concentrations ranged between 1.2 and 335 ug/liter.
Phillips also reported concentrations of mercury in the Tongue River below
the mine effluent at this same time as ranging from <0.2 to 2.3 ug/liter.
The most extensive data available on the water chemistry of the Tongue
River in the region of the Decker Mine have been reported by Whalen (1979),
who studied the chemical limnology of the reservoir. Whalen has considered
the potential impact on the river and reservoir of the mine discharge, and
has extrapolated from his data to consider also the impact from the proposed
expanded mine areas. Water chemistry from Whalen are presented in Tables 14
and 15. Whalen has calculated the average annual discharge of the mine to
be less than 0.1 percent of the Tongue River flow at point of receipt. On
the basis of the values obtained from the chemical parameters measured both
in the receiving water and present mine discharge, Whalen has concluded that
the impact of the mine water discharge on the Tongue River is and will be
negligible for those parameters measured, with the caveat that an unusually
45
-------
Table 14. Averages and ranges (in parenthesis) of some chemical and
physical parameters of the Tongue River Reservoir, November
1975 to November 1976.-'
Parameter
1 i
Ca (meq/£)
Mg (meq/£)
Na (meq/£)
K+ (meq/£)
Total alkalinity (meq/£ CaC03)
S04= (meq/£)
Cl" (meq/£)
Si02 (mg/£)
NH3-N (pg/£)
NOj-N (|jg/A)
N02-N (Mg/£)
PO^-P (pg/£)
Total -P (pg/£)
Station I-7
Reservoir
Above Dam
2.86
(1.26-3.80)
2.99
(0.96-4.29)
1.25
(0.34-1.92)
0.10
(0.04-0.16)
3.70
(1.92-4.70)
3.44
(0.81-5.18)
0.08
(0.03-0.12)
5.6
(1.4-11.8)
24
(0-236)
27
(0-204)
3
(0-20)
10
(0-100)
40
(16-144)
Station 2
Mid-Reservoir
2.79
(1.30-4.31)
2.91
(0.84-4.59)
1.23
(0.29-22.7)
0.10
(0.04-0.16)
3.59
(1.68-5.62)
3.35
(0.66-6.24)
0.08
(0.03-0.13)
5.7
(1.1-10.0)
18
(0-142)
26
(0-187)
3
(0-10)
8
(0-77)
41
(10-109)
Station 3
Reservoir
Upper region
2.81
(1.09-3.63)
2.99
(0.79-3.81)
1.26
(0.28-2.02)
0.10
(0.03-0.13)
3.69
(1.56-4.71)
3.37
(0.54-5.27)
0.08
(0.03-0.12)
6.8
(2.5-13.0)
21
(0-220)
27
(0-47)
3
(0-10)
12
(0-27)
71
(37-260)
46
-------
Table 14. Continued.
Parameter
Spec. cond. (|jmhos/cm @25 C)
pH
Turbidity (JTU)
Temperature (C)
Dissolved Oxygen (mg/£)
Station I-7
Reservoir
Above Dam
660
(246-929)
8.4
(7.5-8.9)
7.3
(1.9-24)
10.6
(1.2-23.5)
8.5
(0.2-13.4)
Station 2
Mid-Reservoir
645
(221-1032)
8.5
(7.5-9.0)
8.6
(1.3-32)
10.9
(1.2-23.8)
9.3
(0.8-19.6)
Station 3
Reservoir
Upper region
654
(197-948)
8.4
(7.9-9.0)
20.3
(5.5-62)
11.4
(1.2-23.9)
10.1
(2.5-17.6)
§/From Whalen (1979).
-Station locations shown in Figure 2.
47
-------
Table 15. Average values of selected parameters measured in the Decker
Mine discharge water and In the Tongue River above and below
the mine discharge, June 1975 to November 1976,, (All parameters
expressed as mg/liter unless otherwise noted.)-
Parameter
PH
Dissolved oxygen
Spec. Cond. (umhos/cm @ 25 C)
Turbidity (JTU)
Temperature (C)
Organic carbon
C03
HC03
Total alkalinity (as CaC03)
S102
Fe
Cl
F
so4
Ca
Mg
Na
K
N02-N (ug/2)
N03~N (ug/£)
Tongue River
above mine
8.6
10.1
693
15
14.7
4.9
4
238
202
7.4
0.028
2.8
0.33
166.4
61.2
37.8
30.5
3.9
3
31
Mine discharge
8.5
9.8
1498
18
14.9
5.2
12
597
509
13.0
0.021
6.8
1.22
295.1
33.1
42.4
253.3
7.7
37
287
Tongue River
below mine
8.4
9.8
696
14
14.7
5.0
4
240
203
7.4
0.024
2.7
0.33
166.4
61.0
37.8
30.4
3.9
3
30
48
-------
Table 15. Continued.
Tongue River Tongue River
Parameter above mine Mine discharge below mine
NH3-N (ug/£) 16 282 16
Total Kjehldahl nitrogen (ug/£) 326 674 333
P04-P (ug/A) 20 6 18
Total -P (ug/£) 62 38 60
Sodium absorption ration (SAR) 0.78 6.88 0.78
§/From Whalen (1979).
49
-------
dry water year could alter his prediction. It should be noted that Whalen
did not report concentrations of heavy metals.
The present study has concerned itself with the movement, age and
growth, and life histories of walleyes and saugers in the Tongue River
Reservoir. Any effect on these fishes as a result of altered water chem-
istry within the reservoir is not apparent from the results of the study.
Fishes from the reservoir do move into the river above the reservoir, but
the extent of this movement and whether this movement is affected by the
mine discharge is not known, and warrants further study. With the intensi-
fication of coal mining planned for this area, we believe that additional
information is needed to plan for adequate safeguards to protect the aquatic
biota of the Tongue River drainage system. Information is now available
which will provide baseline data against which data from future studies may
be compared.
It is of particular concern, in our judgment, to assess the importance
of the Tongue River above the reservoir relative to use by walleye and
sauger for spawning migrations. If reproduction by these species makes a
substantial annual contribution to reservoir populations, any alterations in
water quality and spring flow regimes could significantly affect the
standing crop available to sport fishermen. Such alterations could include
abnormal spring temperatures, reduced flow volumes, dewatering, increased
salinity, and heavy metal loading. Any of these factors, singly or in
combination, could reduce recruitment of walleye and sauger in the Tongue
River Reservoir downstream due to loss of migratory cues, improper condi-
tions for egg deposition and incubation, and downstream transport of larval
fishes.
An incremental increase in recreational use of the river and reservoir
will undoubtedly result from expanded mining or coal conversion operations.
These waters are currently subject to light fishing pressure but a human
population influx could alter use patterns and fishing intensity.
In summary, we believe the following aspects should be studied in some
detail in the near future:
1. Changes in water quality of the river and reservoir (salinity,
temperature, nutrient loading, heavy metal loading).
2. Changes in water quantity (dewatering for offstream storage and
use, and resultant reductions in reservoir storage levels).
3. Changes in fishing pressure and recreational use (including con-
flicts among various user types).
50
-------
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Carlander, K. D., and R. R. Whitney. 1961. Age and growth of walleyes in
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Carufel, L. H. 1963. Life history of sauger in Garrison Reservoir. J.
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Forney, J. L. 1966. Factors affecting first-year growth of walleyes in
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51
-------
Hlle, R. 1941. Age and growth of the rock bass, Ambloolites rupestris
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52
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Snedecor, G. W., and W. G. Cochran. 1967. Statistical methods. Iowa State
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Whalen, S. C. and S. A. Leathe. 1976. Limnology of the Tongue River
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Progress Report submitted to Decker Coal Company of Sheridan, Wyoming,
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53
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
REPORT NO.
EPA-600/3-80-038
2.
3. RECIPIENT'S ACCESSION NO.
«. TITLE AND SUBTITLE
Environmental Effects of Western Coal Surface Hining
Part V - Age and Growth of Walleyes and Saugers in the
Tongue River Reservoir, Montana, 1975-77
5. REPORT DATE
March 1980 issuing date
6. PERFORMING ORGANIZATION CODE
7r.AUTHORtS) ... _ .
Victor L. Riggs and Richard W. Gregory
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Cooperative Fishery Research Unit
Montana State University
Bozeman, Montana 59717
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
R803950
12. SPONSORING AGENCY NAME, AND ADDRESS ,
Environmental Research Laboratory - Duluth, Minnesota
Office of Research and Development
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
EPA/600/03
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A study was conducted between 1975-1977 on the populations of walleye (Stizostedion
vitreum) and sauger (Stizostedion canadense) in the Tongue River Reservoir, in south-
eastern Montana. The Tongue River Reservoir is the recipient of mine water effluents
from the Decker Mine, the largest surface coal mine in the western United States. The
objective of the study was to determine possible impacts of the mine on the walleye
and sauger populations in the reservoir, and to provide data against which future com-
parisons can be made. These species were chosen because they are two of the most impor-
tant game fishes in the reservoir. The age and growth of 640 walleyes and 546 saugers
were determined from collections made in gill nets, trap nets, and by electrofishing.
The 1973 sauger year class and the 1972 walleye year class dominated the catches during
the three years of the study. The movements of taqned fish in late March and early
April 1977 strongly suggested that walleyes spawned in the Tongue River, upstream from
the reservoir. The growth rates for both species were excellent for a northern latitude
reservoir, indicating no noticeable effect by surface coal mine operations at the time
of the study.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Toxicity
Pollution
Coal mining effects
Fish growth
Energy development
Strip mining
Coal mining
Baseline studies
68D
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
64
2O. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (R*v. 4-77) PREVIOUS EDITION is OBSOLETE
54
* US 60VEWIMFHT HUNTING OFFICE. 1980 -657-146/5626
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