LAKE TANEYCOMO - Ozark Anglers

LAKE TANEYCOMO
2013
ANNUAL LAKE REPORT
Shane Bush
Fisheries Management Biologist
Missouri Department of Conservation
Southwest Region
March 1, 2014
EXECUTIVE SUMMARY
Lake Taneycomo was formed by the construction of Powersite Dam (Ozark Beach Dam)
in 1913 and is Missouri's oldest hydroelectric reservoir. It is owned and operated by
Empire District Electric Company (EDEC). The lake is riverine in nature, 22 miles in
length, and encompasses 2,080 surface acres. Prior to 1958, Lake Taneycomo supported
one of Missouri's best warm-water fisheries. This changed in 1958 when Table Rock
Dam, located in the headwater of Lake Taneycomo, began discharging cold hypolimnetic
water into Lake Taneycomo. The discharge of cold water changed Lake Taneycomo into
a cold-water environment, providing good conditions for trout. Rainbow Trout were first
stocked into Lake Taneycomo in 1958. Brown trout were first stocked in 1980. Since
that time more than 30 million Rainbow and Brown Trout have been stocked. Lake
Taneycomo is Missouri's largest and most popular trout fishery. It annually receives in
excess of 140,000 fishing trips and anglers catch an estimated 500,000 trout annually.
The Missouri Department of Conservation (MDC) coordinates fisheries management
activities following the lake management plan that was updated in February 2010.
The 2013 Lake Taneycomo trout electrofishing survey was conducted August 29, 2013.
With the cooperation of the Corps of Engineers and Southwest Power Administration,
hydropower releases were terminated at 2000 hours and sampling began at 2130 hours.
Director Bob Ziehmer and Fisheries Division Chief Brian Canaday were among the crew
of twenty from the Fisheries and Resource Science divisions that assisted with the
sample. What started as a hot, humid, foggy evening ended up to be a rather pleasant
night of sampling. The seasoned and enthusiastic crew helped to make the sample a great
success. Sampling was completed by 0130 hours on August 30.
Rainbow Trout
Rainbow Trout were captured at a rate of 233 fish per hour (Table 1, Figure 1). Size
structure has decreased slightly from previous years; however body condition has
improved with relative weights averaging 97 for all sizes (Table 2). Relative weights of
Rainbow Trout decreased as the lengths of the fish increased. One potential reason for
this decrease could be the length of time that the larger Rainbow Trout have been living
in the lake foraging on natural food sources versus smaller, more recently stocked fish
that have been heavily fed.
Rainbow Trout were collected at a rate of 271 fish per hour in the special regulation zone
above Fall Creek (Table 3, Figure 2). In this same area, PSD13 and PSD16 were 53% and
6%, respectively. Rainbow Trout were collected at a rate of 94 fish per hour below Fall
Creek (Table 3, Figure 3). PSD13 and PSD16 values were 44% and 9%, respectively.
Catch rates and size structure of Rainbow Trout both in the regulation zone and below
remain favorable and are well within the range of normal variation.
The special regulation zone has now been in place for 17 years in upper Lake
Taneycomo. Since the special regulations were implemented in 1997, the Rainbow Trout
population has increased 10-fold (Table 3). Size structure, in general, has greatly
benefited as well. The percentage of stock-size Rainbow Trout at or exceeding 16 inches
has increased above Fall Creek. Currently, PSD16 of 9% falls within the 5-10% objective
listed in the current management plan. Evidence of trophy Rainbow Trout being present
was observed again in 2013 when a potential record sized Rainbow Trout measuring 31
inches long with a girth of 23 inches was caught in the regulation zone (Figure 4). In
addition, this fish was caught near the fish habitat structures installed during the Table
Rock Lake National Fish Habitat Initiative. Body condition of Rainbow Trout has
fluctuated over the past few years. The average relative weight of 88 in 2011 was the
same body condition that was observed during other recent high water years, such as
2008 and 2009. In 2007 and 2010 there was reduced water flow through Table Rock
Dam. Relative weights during these years were noticeably higher. Stable water flows
through Table Rock Dam in 2012 and 2013 have resulted in improvements in relative
weights from 2011. A total of 713,552 Rainbow Trout were stocked into Lake
Taneycomo in 2013 (Table 4).
Brown Trout
The catch per unit effort (CPUE) of Brown Trout was 61 fish per hour (Table 5, Figure
5). Three year classes of Brown Trout stocked from 2011 through 2013 comprised the
majority of the catch. Size structure of Brown Trout continues to increase with PSD13
and PSD16 values measured 76% and 35%, respectively. Currently, the percentage of
Brown Trout equal to or greater than 20 inches remains low with a PSD20 of 3%, but falls
within the lower limits of the management objective of 3-6%. These PSD20 values should
improve in 2014 as the fish stocked in 2011 will be five years old and should begin to
reach the minimum length limit of 20 inches. Body condition of brown trout has
improved from the past couple of years and remains well above normal with average
relative weight of 114 (Table 6). A total of 15,238 Brown Trout were stocked in 2013
(Table 4).
A total of 5,000 triploid Brown Trout were stocked in 2013 as part of the 15,000 fish
commitment. These fish were two years old, averaged 10.46 inches when they were
stocked in May, and had reached 11.78 inches by August. Additionally, the triploid
Brown Trout, as determined by adipose fin clips, made up the majority of the fish
captured in the 10-13 inch range. (Figure 6). The 10,238 diploid Brown Trout that were
stocked in November 2012 as part of the 2013 commitment averaged 12 inches at the
time of stocking and were three years old. The average length of all diploid Brown Trout
sampled in Lake Taneycomo in 2013 was 15.69 inches. An additional 5,000 triploid
Brown Trout will be stocked in Lake Taneycomo each year in 2014 and 2015 as part of
this study and should help the Brown Trout fishery continue to rebound. These triploids
will be stocked along with 10,000 diploids each year for a total of 15,000 Brown Trout
planned to be stocked in 2014 and 2015.
General Lake Activities
Lake Taneycomo experienced a drawdown from November 4-7, 2013. The Corps of
Engineers had to repair a broken ducter discharge valve that siphons the water out of the
Table Rock Dam generators. The Table Rock house turbine remained on at 600 cubic
feet per second (cfs) during this drawdown, which helped to keep the upper portions of
Lake Taneycomo wetted. However, the middle and lower portions of the lake
experienced lower lake elevations as the lake level dropped to 697 feet above mean sea
level at Powersite Dam. No fish mortalities were observed as a direct result of this
drawdown.
The low dissolved oxygen (DO) season in 2013 was the most severe as it has been in the
past few years, resulting in numerous fish mortalities. The vacuum breaker vents were
blocked open at Table Rock Dam on July 10 and restrictions were placed on generation
on August 22. Generation restrictions were lifted and vacuum breaker vents were closed
on December 10. Approximately 50-100 trout were observed dead during the first week
in November (Figure 7). These mortalities were likely the result of low dissolved oxygen
combined with excessive fish handling by anglers as many of these were observed at or
just below the outlets near the hatchery. Most of the trout reported dead were Brown
Trout in the 15-17 inch range, but several Rainbow Trout were observed as well. The
number of mortalities decreased as the dissolved oxygen levels improved throughout
November and December.
In July 2013, MDC met with EDEC to discuss potential options to reduce the number of
invasive aquatic plants in the lake near Empire Park. The plants identified to be the most
problematic were Curlyleaf Pondweed, Coontail, and Southern Naiade. With MDC
providing advice and logistical support, EDEC hired Midwest Lake Management, Inc. to
treat the aquatic vegetation around the park. In August, Midwest Lake Management staff
treated the vegetation using an air boat equipped with droppers to disperse a mix of
Tribune and Komeen into the water to kill the plants in the area (Figure 8). The cost was
approximately $15,000 to treat 25 acres of the lake. Treatments were highly effective at
killing the Curlyleaf Pondweed and Southern Naiade and moderately effective at killing
the Coontail (Figures 9-10). EDEC staff plan to use Midwest Lake Management, Inc.
again in the spring of 2014 to spray the vegetation as it begins to grow and will likely
continue treatments in the future to keep the plants under control.
Management Recommendations
1) Collect trout population information annually for regulation, monitoring, and
triploid study evaluation.
2) Continue to stock 700,000 Rainbow Trout and 15,000 Brown Trout annually,
including 5,000 triploid Brown Trout annually through 2015.
3) Collect information related to trout health to determine the effects of low DO
levels and document trout mortality during the low DO season.
4) Cooperate in ongoing efforts to monitor and enhance water quality and flow
regimes.
5) Continue efforts through education of boaters and anglers to prevent the spread of
zebra mussels, Didymo geminata, and other aquatic nuisance species from and to
Lake Taneycomo.
6) Review and comment on permit applications for boat dock construction and
dredge and fill activities.
Table 1.
Electrofishing capture rates (number/hour) and size structure indices of
Rainbow Trout in August electrofishing samples, 1979-2013. (PSD = Proportional Size
Distribution, the percentage of stock-size fish (11 inches) exceeding a given length, either
13, 16 or 20 inches). back to text
Year
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009*
2010
2011
2012
2013
Number/Hour
256
140
85
95
165
191
103
135
76
101
74
73
68
43
99
44
56
23
101
117
203
185
175
274
219
277
276
175
259
157
313
245
302
248
233
*For Zones 1, 2, and 4b only
PSD-13
14
24
19
7
47
8
13
5
19
8
10
19
<1
8
33
32
25
10
30
46
53
24
31
59
52
43
57
52
55
66
57
70
60
56
52
PSD-16
3
4
6
1
9
<1
5
0
1
1
1
0
0
0
2
2
2
0
2
5
9
3
5
12
13
9
11
6
4
7
9
18
16
9
6
PSD-20
1
1
1
<1
2
0
0
0
0
<1
0
0
0
0
0
1
<1
0
<1
0
<1
0
<1
<1
0
0
0
<1
0
0
0
0
1
<1
<1
Table 2.
Relative weights of Rainbow Trout from Lake Taneycomo, 1993-2013.
back to text
Year
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
All Sizes
111
95
111
106
102
107
104
95
112
112
101
99
96
85
96
88
88
98
88
92
97
Relative Weight by Length Class (Inches)
<13.0
>13.0
110
112
95
97
109
117
107
100
101
102
107
107
104
103
96
90
110
114
109
114
101
100
99
99
100
94
86
84
97
95
88
88
91
87
96
100
88
89
94
89
99
96
>16.0
118
124
102
109
104
81
113
116
99
98
92
86
94
85
84
101
92
85
93
Table 3.
Electrofishing capture rates (number/hour) and size structure indices of
Rainbow Trout in August electrofishing samples, taken above and below Fall Creek,
1996-2013. (PSD = Proportional Size Distribution, the percentage of stock-size fish (11
inches) exceeding a given length, either 13 or 16 inches). back to text
Year
Number/Hour
Above Fall Creek – Regulation Area
1996
27
1997
121
1998
147
1999
238
2000
202
2001
205
2002
334
2003
260
2004
331
2005
315
2006
226
2007
302
2008
187
2009*
449
2010
275
2011
338
2012
278
2013
271
Below Fall Creek – Non-Regulation Area
1996
10
1997
38
1998
18
1999
50
2000
78
2001
64
2002
86
2003
65
2004
64
2005
125
2006
38
2007
55
2008
45
2009
122
2010
120
2011
97
2012
112
2013
94
*For Zones 1 and 2 only
PSD-13
PSD-16
9
31
47
54
25
34
62
55
44
59
53
56
67
62
72
60
58
53
0
2
5
9
3
5
13
14
10
12
6
4
7
11
19
16
9
6
0
11
14
19
5
3
31
17
29
17
46
32
53
28
43
44
24
44
0
0
0
4
2
1
3
2
4
2
8
0
7
0
6
15
2
9
Table 4. 2013 monthly stocking rates in Lake Taneycomo. back to text
Month
Rainbow Trout
Brown Trout
January
47,969
10,000
February
39,874
March
54,500
April
60,103
May
72,125
June
81,971
July
81,025
August
81,034
September
67,632
October
60,332
November
39,477
December
27,510
TOTAL
713,552
5,000
15,000
Table 5.
Electrofishing capture rates (number/hour) and size structure indices of
Brown Trout in August electrofishing samples, 1979-2013. (PSD = Proportional Size
Distribution, the percentage of stock-size fish (11 inches) exceeding a given length, either
13, 16 or 20 inches). back to text
Year
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009*
2010
2011
2012
2013
Number/Hour
2
10
51
132
225
160
188
273
134
66
73
204
62
71
133
113
145
102
175
93
124
100
120
125
84
80
77
101
90
41
33
29
23
107
61
*For Zones 1, 2, and 4b only
PSD-13
60
60
40
10
38
33
14
24
60
57
37
40
44
45
57
38
58
32
42
51
37
59
36
52
59
67
91
76
82
66
87
98
45
51
76
PSD-16
40
7
11
4
10
8
6
2
14
29
17
13
16
11
15
15
20
13
13
17
10
15
8
14
16
23
45
33
39
30
35
67
37
7
35
PSD-20
40
0
1
1
<1
1
<1
<1
0
2
2
2
1
3
3
3
2
2
2
2
2
3
1
1
3
3
2
4
5
5
6
12
20
2
3
Table 6.
Relative weights of Brown Trout from Lake Taneycomo, 1993-2013.
back to text
Year
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
All Sizes
94
100
100
95
96
92
92
91
95
96
95
92
113
105
105
104
109
131
107
103
114
Relative Weight by Length Class (Inches)
<13.0
>13.0
93
94
104
95
102
99
96
94
98
96
95
91
97
87
93
89
97
93
104
92
97
94
94
92
107
113
99
107
102
105
102
105
91
110
100
132
103
128
99
107
103
116
>16.0
96
90
99
89
96
90
79
83
89
91
89
89
123
110
107
105
106
137
133
110
119
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
LAKE TANEYCOMO - 2013
50
45
40
35
30
25
20
15
10
5
0
Effort = 4.5 hr.
233 Total RBT/hr.
N = 1041
PSD (13) = 52%
PSD (16) = 6%
PSD (20) = <1%
0
3
6
9
12
15
18
21
24
Length (Inches)
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
LAKE TANEYCOMO - 2012
50
45
40
35
30
25
20
15
10
5
0
Effort = 4.3 hr.
248 Total RBT/hr.
N = 1073
PSD (13) = 56%
PSD (16) = 9%
PSD (20) = <1%
0
3
6
9
12
15
18
21
24
Length (Inches)
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
LAKE TANEYCOMO - 2011
50
45
40
35
30
25
20
15
10
5
0
Effort = 5.6 hr.
302 Total RBT/hr.
N = 1689
PSD (13) = 59%
PSD (16) = 16%
PSD (20) = 1%
0
3
6
9
12
15
18
21
24
Length (Inches)
Figure 1. Length frequencies for Rainbow Trout sampled in all zones 2011-2013.
N = number of individuals captured back to text
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
SPECIAL MANAGEMENT ZONE
LAKE TANEYCOMO - 2013
50
45
40
35
30
25
20
15
10
5
0
Effort = 3.5 hr.
271 Total RBT/hr.
N = 951
PSD (13) = 53%
PSD (16) = 6%
PSD (20) = <1%
0
3
6
9
12
15
18
21
24
Length (Inches)
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
SPECIAL MANAGEMENT ZONE
LAKE TANEYCOMO - 2012
50
45
40
35
30
25
20
15
10
5
0
Effort = 3.5 hr.
278 Total RBT/hr.
N = 983
RSD (13) = 58%
RSD (16) = 9%
RSD (20) = <1%
0
3
6
9
12
15
18
21
24
Fish/Hr
Length (Inches)
50
45
40
35
30
25
20
15
10
5
0
RAINBOW TROUT LENGTH FREQUENCY
SPECIAL MANAGEMENT ZONE
LAKE TANEYCOMO - 2011
Effort = 4.8 hr.
338 Total RBT/hr.
N = 1610
RSD (13) = 60%
RSD (16) = 16%
RSD (20) = 1%
0
3
6
9
12
15
18
21
24
Length (Inches)
Figure 2. Length frequencies for Rainbow Trout sampled above Fall Creek 2011-2013.
N = number of individuals captured back to text
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
BELOW SPECIAL MANAGEMENT ZONE
LAKE TANEYCOMO - 2013
50
45
40
35
30
25
20
15
10
5
0
Effort = 1.0 hr.
94 Total RBT/hr.
N = 90
RSD (13) = 44%
RSD (16) = 9%
0
3
6
9
12
15
18
21
24
Fish/Hr
Length (Inches)
50
45
40
35
30
25
20
15
10
5
0
RAINBOW TROUT LENGTH FREQUENCY
BELOW SPECIAL MANAGEMENT ZONE
LAKE TANEYCOMO - 2012
Effort = 0.8 hr.
112 Total RBT/hr.
N = 90
RSD (13) = 24%
RSD (16) = 2%
0
3
6
9
12
15
18
21
24
Length (Inches)
Fish/Hr
RAINBOW TROUT LENGTH FREQUENCY
BELOW SPECIAL MANAGEMENT ZONE
LAKE TANEYCOMO - 2011
50
45
40
35
30
25
20
15
10
5
0
Effort = 0.8 hr.
97 Total RBT/hr.
N = 79
RSD (13) = 44%
RSD (16) = 15%
0
3
6
9
12
15
18
21
24
Length (Inches)
Figure 3. Length frequencies for Rainbow Trout sampled below Fall Creek 2011-2013.
N = number of individuals captured back to text
Figure 4. A Rainbow Trout measuring 31 inches caught in Lake Taneycomo in 2013. back
to text
BROWN TROUT LENGTH FREQUENCY
LAKE TANEYCOMO - 2013
Fish/Hr
20
18
16
14
12
10
8
6
4
2
0
Effort = 4.5 hr.
61 Total BNT/hr.
N = 271
PSD (13) = 76%
PSD (16) = 35%
PSD (20) = 3%
0
3
6
9
12
15
18
21
24
27
30
Length (Inches)
BROWN TROUT LENGTH FREQUENCY
LAKE TANEYCOMO - 2012
Fish/Hr
20
18
16
14
12
10
8
6
4
2
0
Effort = 4.3 hr.
107 Total BNT/hr.
N = 463
PSD (13) = 51%
PSD (16) = 7%
PSD (20) = 2%
0
3
6
9
12
15
18
21
24
27
30
Fish/Hr
Length (Inches)
20
18
16
14
12
10
8
6
4
2
0
BROWN TROUT LENGTH FREQUENCY
LAKE TANEYCOMO - 2011
Effort = 5.6 hr.
23 Total BNT/hr.
N = 129
PSD (13) = 45%
PSD (16) = 37%
PSD (20) = 20%
0
3
6
9
12
15
18
21
24
27
30
Length (Inches)
Figure 5. Length frequencies for Brown Trout sampled in all zones 2011-2013.
N = number of individuals captured back to text
BROWN TROUT TRIPLOID LENGTH FREQUENCY
LAKE TANEYCOMO - 2013
5
Fish/Hr
4
Effort = 4.5 hr.
11 Total BNT/hr.
N = 49
3
2
1
0
0
3
6
9
12
15
18
21
24
27
30
Length (Inches)
BROWN TROUT DIPLOID LENGTH FREQUENCY
LAKE TANEYCOMO - 2013
5
Fish/Hr
4
3
Effort = 4.5 hr.
42 Total BNT/hr.
N = 188
PSD (13) = 93%
PSD (16) = 46%
PSD (20) = 4%
2
1
0
0
3
6
9
12
15
18
21
24
27
30
Length (Inches)
Figure 6. Length frequencies for triploid and diploid Brown Trout sampled in all zones
in 2013. N = number of individuals captured back to text
Figure 7. Dead trout observed in upper Lake Taneycomo on November 5, 2013.
back to text
Figure 8. Airboat equipped with droppers dispersing chemical into Lake Taneycomo to
treat aquatic vegetation. back to text
Figure 9. Dying Coontail in Lake Taneycomo following chemical treatments.
back to text
BEFORE
AFTER
Figure 10. Pictures of Lake Taneycomo by Empire Park before and after chemical
treatments. back to text