OKATIBBEE LAKE PASCAGOULA RIVER, MISSISSIPPI DESIGN

OKATIBBEE LAKE
PASCAGOULA RIVER,
MISSISSIPPI
DESIGN MEMORANDUM
THE MASTER PLAN
APPENDIX D - FISH MANAGEMENT PLAN
._-----------A publication prepared under terms of a contract research
project between the Corps of Engineers, Mobile District and the
Agricultural Experiment Station of Auburn University, AubLU'n,
Alabama. The departments of Agricultural Economics and Rural
Sociology and Fisheries and Allied Aquacultures were responsible
for the research and development of this report.
Auburn University staff members with major responsibilities
for the research and development of this report were David R.
Bayne, Carolyn Carr, Wm. Dumas HI, J. D. Grogan, John M.
Lawrence, David Rouse, Karen Snowden, Glenn stanford, David
Thrasher, Charles J. Turner, and J. Homer Blackstone as
project leader.
U. S. ARMY ENGINEER DISTRICT, MOBILE
CORPS OF ENGINEERS
MOBILE, ALABAMA
July 1974
TABLE OF CONTENTS
Text
1.
2.
Introduction
1
A.
Purpose
1
B.
Master plan
1
C.
Fish management
1
D.
Classification of fishery
1
Physical Characteristics of the Aquatic Habitat that Influence
Fish Production and Harvest
2
A.
General
2
B.
Drainage area
2
C.
1.
Topography
2
2.
Area
2
3.
Land usage
4
4.
Rainfall patterns
4
5.
Runoff rates
6
6.
stream regulation
6
6
Impoundment
1.
Morphometry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
2.
Altitude
6
3.
Area
4.
Mean depth
5.
Maximum depth
.................•..................................... 10
. . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . .. 10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10
3.
6.
Productive-depth zone
...........•.....................•...• 10
7.
Volume of the euphotic strata
8.
Length of shoreline
9.
Eulittoral zone
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
11
. . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
11
10.
Inflow
11
11.
Outflow
11
12.
Rentention time
11
13.
Internal flow currents
12
14.
Penstock depth
12
15.
Water-level fluctuation
12
16.
Uncleared flooded areas
12
17.
Meteorological influence
12
Water Quality in Relation to Fish Production
13
A.
General
13
B.
Water quality constituents
13
1.
2.
Temperature
13
a.
Stratification in lake
14
b.
Condition in tailwaters
14
Dis soIved oh-ygen
15
a.
Stratification in lake
17
b.
Condition in tailwaters
17
3.
pH
18
4.
Carbon dioxide and alkalinity
18
ii
5.
Chemical type
6.
Plant nutrients
7.
8.
C.
4.
. ... . . . .. .. . .. . .. .. . .. . .. .. . .. . .. .. . .. . .. .. ..
. . . . . . . . . . . .. 23
a.
Nutrient enrichment in impoundments
. . . . . . . . . . . . . . . • . . ..
23
b.
Macro-nutrients
. . . . . . . . . . . . . . . . • . . . . . • . . . . . . . . . . . . . . ..
25
c.
Micro-nutrients
. . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
25
d.
Nutrient sources
.........................•..........•..
27
. . . • . • . . • . . . . • . . . . . . . . . • • • . . . • . • . • • . • . . . ..
29
Toxic substances
a.
Pesticides
b.
Heavy metals
c.
Industrial toxicants
29
30
. . . . . . . . . . . . . . . . . ..
30
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . • . . • . . . . ..
30
. . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . • . . . . . . • • . . . ..
32
Sediment load
Pollution sources
. . • . . . . • . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . . ..
Aquatic Plants in the Impoundment
• . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . .. 33
A.
Aquatic plant-definition
B.
Factors affecting aquatic plant growth
C.
Aquatic plant groups and associated habitat problems
D.
21
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
33
. . . .. . .. .. . . . . .. .. . .. . .• .. .. 33
.. .• . .. . .. .. ..
34
1.
Bacteria
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . .. 35
2.
Fungi
............•......•......... "
3.
Algae
............•.......... , ..•.•.. , .. . .. . .. .. ... . .. .. .. 35
4.
Flowering plants
,. .. .. .. 35
... , . ... . . .. ... .. . .. . ... . . .. . .. .. . .. . .. .. .. 39
Aquatic plant problems on Okatibbee Lake and methods for their
control
iii
41
5.
Description of the Fi shery
43
A.
Warmwater species of fish in Okatibbee Lake
43
B.
Coldwater species of fish in Ol<atibbee Lake
43
C.
The downstream species from Okatibbee Lake
43
D.
Rare and endangered species
49
E.
Fish-food organisms
49
F.
History of parasite and disease incidents in fish populations
49
G.
History of fish kills
52
H.
Establishment of Okatibbee Lake fishery including flooding schedule. .
52
1.
History of species composition, relative abundance, and condition
within each species including methods used to obtain fish samples. ...
63
1.
6.
Methods of sampling fish populations
63
a.
Rotenone sampling
64
b.
Electrofishing
66
2.
Fish population studies (rotenone)
67
3.
Fish population studies (electrofishing 1970 and 1973) •...•.....
72
4.
Comparisons of relati ve condition (Kn)
72
J.
Fishing pressure
78
K.
Creel census data
78
MANAGEMENT OF THE FISHERY ............•......................
84
A.
84
Reservoir fishery biology
1.
Factors affecting fish reproduction
85
a.
Adequacy of spawning area
85
b.
Water fluctuation
87
iv
2.
Water temperature •..............................•....... 87
d.
Silt-laden waters
e.
Repressive factor ..............•......................... 88
f.
Size of brood fish
88
g.
Food availability during period of egg formation
88
h.
Crowding'. . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .• 88
i.
Egg-eating habit. . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . • . . . . . . .. 89
j.
Reproductive success of prey upon which predators feed
after reaching finger ling stage. . . . • . . . . . . . . • . . . • . . . . . . . . . . .. 89
k.
strength of predation upon young predator species
...........•............................ 87
89
Predator-prey relationships .................................•. 89
B.
Re'sum~ of factors affecting fish production in reservoirs
C.
Information vs. action ......•........................•.........•.. 100
D.
7.
c.
98
1.
Public relations
2.
Fishing access ..............•.............................•.. 101
3.
Fishing intensity .............•............................... 102
4.
Creel limits .•............................................... 102
5.
Evaluation of fishery management changes ...............•.....• 103
6.
Fishing tournaments and rodeos
Creel census evaluations
101
•••.....•..•..........•....•..• 104
..................................•.....• 105
Coordination with Other Ag'encies .•..............................•...... 106
A.
Personnel and funding
106
B.
Cost-benefit projections •.......•..•............................•. 107
v
C.
Equipment for biologist ........................................•... 108
D.
Job description - Fisheries Management Biologist
E.
Budget. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 111
109
8.
Research Needs for River and Impoundment Management
9.
Synopsis
112
" .. . .. . . . . . . . . . .. .. 116
vi
TABLES
Table
1.
Unit hydrograph of Okatibbee Reservoir inflow.
7
2.
Rainfall-runoff relation for Okatibbee Creek.
8
3.
Average concentrations of macro-nutrients (elements) in filtered
water, suspended matter, bottom soils, and fish from Okatibbee
Lake.
26
Average concentrations of micro-nutrients (elements) in filtered
water, suspended matter, bottom soils, and fish from Okatibbee
Lake.
28
Average concentrations of heavy metal elements in filtered water,
suspended matter, bottom soil, and fish from Okatibbee Lake.
31
List of phytoplankton genera collected from Okatibbee Lake in
1973.
38
List of flowering aquatic plants along the shoreline of Okatibbee
Lake, October, 1973.
42
A checklist of warmwater fish species believed to be present in the
Pascagoula River, separated into game, commercial, and other
groupings.
44-48
Macroinvertebrates collected from the Okatibbee Lake area in 1967.
50-51
10.
Probable fish parasites in the Pascagoula River Basin.
53-59
11.
Viral, bacterial, and fungal diseases of reservoir fish.
60-61
12.
Fish population data collected by rotenone sampling in Okatibbee
Lake in 1971-1972.
68-69
Lengths (in inches) used to classify fish of different species as
yOlmg, intermediate, or harvestable, and as forage, carnivorous
or other.
73-74
Total numbers of various groups of fish sighted in the electrofishing
field during four hours of shocking on Okatibbee Lake in May, 1974.
75
4.
5.
6.
7.
8.
9.
13.
14.
vii
TABLES, cont'd.
Table
15.
Sights-per-minute of various groups of fish observed by electrofishing in Okatibbee Lake in May, 1974.
76
The estimated number of fishermen, hours fished, number of
fish and the pOlmds of fish caught from Okatibbee Lake in 19711972.
80
The number and weight composition of species in total creel from
Okatibbee Lake for 1971-1972.
81
The estimated number of fishermen, hours fished, number of
fish and the pounds of fish caught from Okatibbee Lake in 19721973.
82
The number and weight composition of species in total creel from
Okatibbee Lake for 1972-1973.
83
20.
Reproductive characteristics of various species of freshwater fish.
86
21.
Maximum sizes of forage fishes largemouth bass of a given inchgroup can swallow.
91
16.
17.
18.
19.
viii
FIGURES
Title
1.
Okatibbee Basin,
3
2.
Lake Okatibbee.
9
3.
Oxygen content of water and its relation to fish.
16
4.
Relationship of pH of reservoir waters to their suitability for
fish production.
19
Relationship and determination of CO2 , HC03 ,C03
in natural waters.
20
5.
6.
,and OH
Distribution of K factor for various sizes of four groups of fish
n
collected from Okatibbee Lake in 1974.
ix
77
Fish Management Plan
for
Okatibbee Lake
1.
Introduction.
I-A.
Purpose. This report on the fishery management of Okatibbee Lake
presents a plan to preserve all species of fish within the impoundment, to increase
the production of harvestable-sized fish through the improvement of the aquatic
habitat, and to provide the most favorable lake conditions for public fishing.
I-B.
Master plan.
The fish management plan will be a part of the approved
Master Plan for the continued development and management of Okatibbee Lake.
I-C.
Fish management.
Fish management (Appendix D) will be in accordance
with ER 1130-2-400, App. A (May, 1971); ER 1120-2-400; ER 1120-2-401; AR420-74; Fish and Wildlife Coordination Act of 1958 (PL 85-624) as amended; and
Federal Water Projects Recreation Act of 1965 (PL 89-72).
I-D. Classification of the fisherv.
The fishes in Okatibbee Lake have been
classified as warmwater sport, commercial, and miscellaneous species.
They
are to be managed to provide the puhlic with the maximum sustained yield of harvestable sizes of sport and commercial species and to insure the continued existence
of the miscellaneous species.
2.
Physical Characteristics of the Aquatic Habitat that Influence Fish Production
and Harvest.
2-A.
General.
Aquatic habitats are as numerous as the waters themselves.
Rising in mountains, hills, or plains, small streams meander through the countryside uniting with one another to form larger streams and eventually a river.
Each
change in size and shape forms a new habitat with a new set of envirolilllental
conditions and a different assemblage of aquatic organisms.
however, are never independent of upstream influences.
made impolUldments on rivers.
These new conditions,
The same is true of man-
Morphometric features of the impoundment will,
to a great ell.1:ent, determine the types of aquatic habitats, but environmental conditions in the lake will largely depend on quality and quantity of the collective
waters from the drainage area.
The physical features of Okatibbee Lake and its
associated drainage area are presented in this section of the report.
2-B.
Drainage area.
2-B-L
Topographv.
The Okatibbee Creek rises in the rolling plains
area of tIE Southern Red Hills Region of the East Gulf Coastal Plain Province.
This is an area with low hills and relatively wide, flat valleys.
The portion of
Okatibbee Creek drainage that is above Okatibbee Dam is apprOXimately 36 percent
of its total area (Figure 1).
2-B-2. Area.
The total area of the watershed for Okatibbee Lake is
154 square miles.
2
,
,
,
Hwy. 16
Figure l.
OKATIBBEE
-'\,
BASIN
,
",,,,
,
,
\,
,
...
..,
'.,
,
.
'.
\,
'.
\"\
"---....
--.".,\
\,
,
,,
,,
,
,/'/
,,
,,
,
,J
,
,,-'
"..... /
~
",,$'/,,
,
~v-/
,,
,,
I,
,,
,,
,,,
;
,,
I
,
o "
~
"
\
,
,,
,:
3
I
I
_/
,./
:'
"
/
2-B-3.
Land usage.
Prior to World War II, this portion of the Okatibbee
Creek drainage had a relatively large rural population that engaged in extensive
row-crop farming.
Lands in the Coastal Plain are generally less subject to gully
erosion but have an annual sediment load of 20 to 40 tons per square mile.
During and following World War II the decline in rural population allowed the
land to revert to forest or be converted into pastures. By 1970 the cover on the
upper portion of the Okatibbee watershed was about 50 percent forest, and 35
percent grass and crop lands.
The remaining 15 percent of the land area was
occupied by residential, business, industrial, and transportation facilities.
This
change in land use has resulted in a reduction of the sediment load in the Okatibbee
Creek. A notable exception to this low sediment situation occurs when construction practices are careless.
2-B-4. Rainfall patterns.
of fairly heavy rainfall.
The Okatibbee drainage area is in a region
The normal monthly and annual precipitation throughout
the basin above Okatibbee Dam is shown on the follOWing page (1961 normals
published by the U. S. Weather Bureau).
4
Month
--
Inches
--
January
5.06
February
5.15
March
6.39
April
5.42
May
3.99
June
3.89
July
6.31
August
3.51
September
3.56
October
2.56
November
3.54
December
5.36
ANNUAL
54.74
There is seasonal variation, with about 50 percent of the precipitation occurring'
during the wet period (December through April) and only about 24 percent occurring
during the dry period (August through November).
Flood-producing storms may occur over the Okatibbee basin at any time
during the year, but they are more frequent in winter and early spring.
Major
winter storms are usually of the frontal type and summer storms of the convectional type.
5
2-B-5. Runoff rates.
Due to an abundant rainfall in its headwaters, the
small size of the drainage area, and the general topography of the basin, the
Okatibbee Creek has a fairly high rate of runoff - as shown in Table 1. The rainfallrunoff relation for this basin is shown in Table 2.
Flooding of Okatibbee Lake is
most likely to occur from December through April.
2-B-6.
Stream regulation.
Okatibbee Lake was built to serve as an
upstream flood-control and downstream low flow augmentation structure.
The
only stream regulation above Okatibbee Dam is minor and is provided by small
farm fish ponds.
2-C.
Impoundment.
The physical characteristics of a basin that is illlUldated
have considerable influence on the production of fish in the subsequent impOlUldment.
The physical features of Okatibbee Lake which influence the production and harvest
of fish are described below.
2-C-1.
Morphometry.
Okatibbee Lake may be described as a large fishing
lake which receives too much flood water.
The terraine in which the lake was estab-
lighed is relatively flat, as indicated by the shape of the lake shown in Figure 2.
2-C-2. Altitude.
is 343 feet msl.
The elevation of Okatibbee Lake at normal upper pool
The elevation of the hills surrounding the reservoir varies between
375 and 425 feet msl.
6
Table 1. Unit hyclrograph of Okatibbee Reservoir inflow.
6 hour unit
Hyclrograph
Time in hours
0
0
6
1,300
12
900
18
2,550
24
2,580
30
3,420
36
2,390
42
1,250
48
860
54
580
60
390
66
230
72
90
78
20
84
0
7
Table 2.
Rainfall-runoff relation for Okatibbee Creek '.
Antecedent Average basin
rainfall in
conditions
inches
(storm total)
Average runoff in inches
.4
.5
.6
.7
.8
.9
1, 29
1, 90
2.54
.07
.31
.78
1, 35
1, 96
2.60
.09
.35
.84
1,40
2.02
2.67
.11
.38
.89
1,47
2.08
2.74
.13
.43
.95
1, 53
2.14
2.80
.16
.47
1, 00
1, 59
2.21
2.87
.18
.52
1, 06
1, 65
2.27
2.94
.02
.14
.27
.42
.59
.75
.03
.15
.29
.44
.60
.77
.04
.16
.30
.46
.62
.79
.05
.18
.32
.47
.64
.80
.06
.19
.33
.49
.65
.82
.07
.20
.35
.50
.67
.84
.09
.22
.36
.52
.69
.86
.10
.23
.38
.54
.70
.87
.01
.08
.17
.28
.43
.62
.02
.09
.18
.29
.45
.64
.02
.09
.18
.30
.47
.66
.03
.10
.19
.32
.48
.68
.04
.11
.20
.34
.50
.70
.04
.12
.21
.35
.52
.72
.05
.13
.22
.37
.54
.74
.06
.14
.24
.38
.56
.77
0
.1
.2
0
1
2
3
4
5
6
0
.20
.56
1,12
1,71
2.34
3.00
.02
.23
.61
1,17
1, 77
2.40
.04
.25
.67
1, 24
1, 83
2.47
Normal
0
1
2
3
4
5
6
0
.11
.25
.39
.55
.72
.89
.01
.12
.26
.41
.57
.74
Dry
0
1
2
3
4
5
6
0
.06
.15
.25
.40
.58
.79
0
.07
.16
.26
.42
.60
Wet
00
•3
.05
.28
.72
, Based on the rainfall-runoff relationship of nearby reservoirs which are considered representative of the Okatibbee area.
N
', ..
':~/" .
."
Figure 2.
LAKE OKATIBBEE
9
2-C-3. Area.
The normal upper pool (343 feet msl) surface area of
Okatibbee Lake is 3,800 acres.
This area varies, depending upon flood water
storage and downstream low flow augmentation.
2-C-4.
Mean depth.
The mean depth of Okatibbee Lake at normal upper
pool elevation (343 feet msl) is 11.1 feet.
2-C-5.
Maximum depth.
At a point immediately above Okatibbee Dam the
water is approximately 32 feet deep (at normal upper pool elevation of 343 feet msl).
2-C-6.
Productive-depth zone.
Within any body of water a certain area
supports most of the aquatic life found there.
Several limiting factors determine
the lower depth of this productive zone in a lake.
One factor is the point in depth
at which the total quantity of surface light is reduced by 99 percent.
Another factor
is that point in depth at which the dissolved Q),'ygen concentration in the water is less
than 1 ppm.
Since these limits vary as a result of other lake conditions, the 12 foot
depth will be considered the approximate bottom of the productive zone in Okatibbee
Lake.
2-C-7.
Volume of the euphotic strata.
The volume of the various euphotic
strata, which comprise the primary productive areas of lake waters, determines
the quantities of nutrients in the lake that may be efficiently converted into phytoplankton.
The voltmles of the 3-, 6-, 9-, and 12-foot stratum in Okatibbee Lake
are given below.
10
to
to
to
to
343
340
337
334
2-C-8.
340
337
334
331
feet
feet
feet
feet
10,080
8,010
6,600
5,360
msl
msl
msl
msl
Length of shoreline.
acre-feet
acre-feet
acre-feet
acre-feet
The productive zone of a lake, as well as its
accessibility to banle fishermen, is related to the length of its shoreline.
This length
is also used in the calculation of shore development. The shoreline at Okatibbee Lake
is 28 miles long and the shore development for the lake is 3.21 which is the ratio between the actual shoreline and the circumference of a circle whose area equals that
of Okatibbee Lake.
2-C-9.
Eulittoral zone.
high- and low-water levels.
The eulittoral zone is that bottom area between the
The summer pool elevation of Okatibbee Lake is 343 feet
msl and the conservation pool (December tln'ough March) elevation is 339 feet msl. The
area between these two levels is 1,080 acres and the volume is 12,950 acre feet.
2-C-10. Inflow.
200 cfs.
Average annual flow into Okatibbee Lake is estimated at
The maximmn flow at tillS point was about 17,000 cfs in February, 1961.
A minimum flow of <1. 0 cfs was recorded in October, 1952.
2-C-ll.
Outflow.
The average daily flow at Okatibbee Dam site was approxi-
mately 203 ds for the period 1938-1962. The maximum flow was 17,400 cfs in February, 1961 and the minimum daily flow was 0.7 cfs in October, 1952.
2-C-12.
Retention time.
Based upon an average discharge of 203 cfs, the
water exchange rate would be about 105 days in Okatibbee Lake or 3.5 times per year.
II
2-C-13.
Internal flow currents.
Little is known of internal flow currents
in Okatibbee Lake. Due to its shallow overall depth, convection currents and wind
driven currents would occur daily within the upper epilimnon during warm weather.
2-C-14.
Penstock depth.
There are no penstocks on Okatibbee Dam,
but the opening to the outlet works extends from elevation 310 to 321 feet ms!'
Thus,
the waters discharged downstream are taken from the lower level of the lake.
2-C-15. Water-level fluctuations.
The water level in Okatibbee Lake is
maintained near elevation 343 feet msl from May through October. There may be
slight fluctuations above or below this level due to heavy rains, or for low flow augmentation during drier periods.
Maximum drawdown for water quality control and
water supply is to 328 feet ms!.
2-C-16.
Uncleared flooded areas.
Trees were cleared from the entire
reservoir area. There were no specific uncleared areas flooded as a benefit to
sport fisheries.
2-C-17.
Meteorological influence.
Weather conditions are a major in-
fluence on the water quality in Okatibbee Lake during the summer months.
Hot,
dry periods do produce chemical stratification that can be partially or completely
disrupted by a heavy rainstorm.
Winter storms and their accompanying flood waters muddy the lake and this
may occur in the spring and interfere with bass and crappie reproduction.
12
3. Water Quality in Relation to Fish Production.
3-A.
General.
The quality of impounded stream waters largely determines
the quality and quantity of aquatic life in the lake. The water quality of a stream
is, in turn, the product of its watershed.
The stream receives leached, washed-
off, and dlUl1ped contributions from agricultural, industrial, and urban use of the
drainage area.
3 -B. Water quality constituents.
Since water is the medium in which
aquatic plants and animals spend most of their existence, water conditions must
be optimum for survival, growth, and reproduction of aquatic life.
Those water
quality parameters that are most important to aquatic life include temperature,
dissolved oxygen, pH, carbon dioxide and alkalinity, chemical type, plant nutrients,
toxic substances, and sediment load.
Each of these water quality parameters is
discussed below.
3-B-1. Temperature.
The water temperature in a lake determines the
type of aquatic life that it can support. In the Southeast, water temperatures range
from about 40 0 to 95 0 F.
Generally, weather conditions control surface water
temperatures, but the activities of man can sometimes alter the temperature of
waters.
Some obvious examples of the latter case are the construction of deep-
water impOlUldments, the winter storage of cold waters, and the release of heated
water from industrial cooling systems.
13
3-B-1-a. Temperature stratification in lake.
In all bodies of water
there is a tendency for the entire volume to be homogeneous in temperature during
the winter period.
However, as the weather warms up in the spring the surface
water temperature of the lake begins to rise.
Then as summer approaches, there
is an increasing temperature difference between the surface and the bottom. The
magnitude of this difference depends upon the water depth and the quantity and
quality of inflowing and outflowing waters.
In lakes the size of Okatibbee, the summer thermal pattern starts at the
surface layer or epilimnon, where surface temperatures approach or may exceed
mid-day air temperatures.
Descending in depth, the water temperatlll:e decreases
until it approaches a thermocline.
In Okatibbee Lake the epilimnon begins to warm-up in March and by June may
have attained its maximum temperature for the summer.
sli~tly
The water temperature
decreases with depth, but the stratification never attains a stable thermo-
cline. Any unstable thermal situation can be disrupted by a heavy summer thunderstorm or by prolonged high winds.
3-B-1-b. Temperature conditions in tailwaters.
Since the tempera-
ture of the water immediately above Okatibbee Dam varies from uniform in the
winter to somewhat stratified in the summer, and the discharge intake draws
bottom waters, the tailwaters will be only a degree or so warmer than these
bottom waters.
From the available information the tailwaters would never be
more than 4 0 C cooler than the sm'face waters in Okatibbee Lake.
14
3-B-2. Dissolved oxygen.
Water must contain an adequate supply of
dissolved oxygen in order to support aquatic life. Ranges of dissolved oxygen
concentrations in relation to freshwater fish production are shown in Figure 3.
Factors which affect the quantity of dissolved oxygen in water include temperature, presence of oxidizable materials, respiration requirements of plants
and animals, and the abtmdance of phytoplankton.
The oxygen absorbing capacity
of water increases as the water temperature decreases.
However, the amount of
oxidizable organic and inorganic materials in the water determines the degree of
saturation that will be maintained.
Although water can absorb oxygen from the atmosphere, such absorption is
limited to the surface layers of lakes.
Since a lake needs dissolved oxygen more
during the warm weather period when absorption is lower, a more efficient oxygen
source is required.
called phytoplankton.
Such a source is prOVided by the microscopic aquatic plants
These plants produce free o>,j'gen as a by-product of the
process of photosynthesis. TlJis process is so efficient that waters supporting a
moderate-sized population can become supersaturated with oxygen.
An overabtmdance of phytoplankton can be detrimental to the overall oxygen
situation in a lake. Dense growths reduce the depth to which sunlight can penetrate,
which in turn restricts the amount of photosynthesis.
Thus, oxygen production
occurs only near the water surface, even though the oxygen demand below this layer
is increased by dead plants settling toward the bottom. Also the dark period respiratim of this dense plant population may use most of the previously produced
15
Pond Fish
>-'
'"
Lethal
point for
pond
fish
(
Small bluegills may
survive if
CO is low.
2 J
ppm
dissolved oxygen
0.1
Usable range for pond fish
"
I
~
0.2
-v
0.3
1.0
2.0
Desirable range for pond
fish
3.0
l'
Danger point
for stream
fish
Stream Fish
Figure 3.
Oxygen content of water and its relation to fish.
4.0
5.0
;:.
;>
R-
Desirable
range for
stream
fish
:;>
excess dissolved oxygen. The supersaturation of sm'face waters resulting from
excess oxygen production is not necessarily beneficial to a lake, since much of
this supersaturation is lost to the atmosphere if the area is subject to wind-wave
action.
In Okatibbee there are sufficient plant nutrients to support a moderate to
abundant growth of phytoplankton.
Thus, dissolved oxygen concentrations in
surface waters should be slightly less than - to greater than - saturation at all
times.
3-B-2-a.
Dissolved oxygen stratification in lake.
The dissolved
oA'Ygen (D, 0.) concentrations in Okatibbee Lake are usually fairly homogeneous
during those same cold weather periods when water temperatures are Lmiform at
all depths. As the surface waters begin to warm up, the dissolved oxygen satm'a-
tion level decreases.
In addition, organic and inorganic oxidation processes
begin to speed up and fish and other aquatic life become more active. All of these
factors require more oxygen.
As hot weather approaches, the dissolved oxygen in sLU'face waters remains
near saturation levels, but the degree of saturation decreases with increasing
depth.
Under stratified conditions the dissolved oxygen content may be at or near
zero below the 10-15 foot depths.
3-B-2-b. Dissolved oxygen conditions in tailwaters.
The intake
gates on Okatibbee Dam open at a level that permits withdrawal of water from the
bottom of Okatibbee Lake. After passage through the dam this water is released
17
in a stilling basin equipped with cross walls that not only reduce the waters forces
but also act as agitators that increase the absorption of oxygen into the water.
3-B-3. pH. The pH of surface waters is a measure of whether the
water has an acid or basic reaction.
In most natural surface waters pH reflects
the quantity of free carbon dioxide present.
Such waters generally fall in the pH
range of 6.0 to 9. 5, which is the range tolerated by freshwater fish.
Normally,
surface waters fluctuate between these two e,,1:remes every 24 hours as a result
of photosynthetic activity. Aquatic plants use the C02 and sunlight to produce 02
during the day, thus raising the pH toward 9.5. At night these plants respire,
releasing CO2 and depressing the pH toward 6. O.
Some surface waters, such as mine drainage wastes, may accumulate acids
that have leached from the exposed soiL
Other waters may contain acidic or basic
wastes from industrial operations.
The pH of water in Okatibbee Lake falls within the range of 6.0 to 9.5. The
relationship of pH to the SUitability of a lake for fish production is shown in Figure 4.
3-B-4. Carbon dioxide and alkalinity.
Most natural waters are buffered
by a carbon dioxide-bicarbonate-alkalinity system.
The relationships of C02'
HC0 -, C0 --, and OH- in natural waters are shown in Figure 5 .
3
3
Carbon dioxide is a natural component of all surface waters. It may enter the
water from the atmosphere but only when the partial pressure of carbon dioxide in
the water is less than in the atmosphere.
Carbon dioxide can also be produced in
18
ACID
DEATH
POINT
ALKALINE
DEATH
POINT
>-'
'"
(
TOXIC
TO
LOW
FISH
DESIRABLE
,
11,
3
4
NO
REPRODUCTION
1
>JI
iJ
5
RELATIONSHIP
RANGE
LOW
FOR
PRODUCTION
If
FIGURE 4.
>
<
)0
6
OF pH
FISH
TOXIC
PRODUCTION
TO
FISH
PRODUCTION
.,
It
7
8
9
OF RESERVOIR WATERS
FOR FISH PRODUCTION
10
TO
THEIR
II
12
SUITABIL\ TY
~
Total Alkalinity
<
)
Bicarbonate Alkalinity
)
(
Carbonate and OH Alkalinity
)
Range of Occurrence of COS
Amount Determined by Titration with HCl.
'"o
NaHCOS
(
Na2COS + HCl
'-
Range of Occurrence of HCO S-. Amount
Determined by Titration with HCl.
CO 2,
pH
= 4.5
Figure 5.
(
NaHCOS + HCl
'"
BCO S
Concentration
,I, Decreasing
8.S
Free OH- Occurs in this Range,
Usually Only in Polluted Waters.
)
10.0
,I,
11. 0
Relationship and dete=ination of CO 2 , HCO S-, COS--, and OH- in natural waters.
12.0
IS.0
waters through biological oxidation of organic materials.
In such cases, if the
photosynthetic activity is limited, the excess carbon dioxide will escape to the
atmosphere.
Thus, surface waters are continually absorbing or giving up carbon
dioxide to maintain an equilibrium with the atmosphere.
The alkalinity of natural waters is due to the presence of salts of weak acids.
Bicarbonates represent the major form of alkalinity since they are formed in
considerable amounts by the activity of carbon dioxide upon basic materials in
the soils.
Under certain conditions natural waters may contain considerable
amounts of carbonate and hydroxide alkalinity. This situation often exists in
waters supporting a moderate to heavy growth of phytoplankton.
These algae re-
move free and combined carbon dioxide to such an e,rtent that a pH of 9.0 to 10.0
often exists.
3-B-5. Chemical type.
The total hardness, total chloride, and total
sulfate content of surface waters indicates its chemical type, particularly where
the source of these ions is attributable to the soil formation in the drainage area.
Conductance measurements are also included under this heading since it may be
used to detect changes that may occur in the relative abundance of the above mentioned ions.
Total hardness is primarily a measure of the total divalent metallic and alkaline earth elements in solution in the water.
calcium and magnesium concentrations.
In most surface waters it measures
The range in total hardness in waters
from Okatibbee ranged from 14 to 20 ppm as CaC03 , with magnesium hardness
accounting for about 40 percent of the total concentrations.
21
It should be noted that water hardness is a direct reflection of the geology of
the drainage area.
Lake waters have an appreciable total hardness only when
CO enriched waters flow over or through soluble limestone formations on its
2
way to the laJ<e. Total hardness also has a direct bearing upon the total alkalinity
of soft water lakes.
In this section of the United states the amount of total chlorides generally
indicates the degree of domestic and industrial pollution. In the West, however,
total chlorides may reflect the type of drainage area. A maximum concentration
of less than 10 ppm total chlorides would be considered normal in water of Okatibbee Lake.
Total sulfates, like total chlorides, are usually an indication of domestic or
industrial pollution here in the Southeast.
In the West, total sulfates may indicate
the type of drainage area. A maximum concentration of less than 10.0 ppm total
sulfates would be considered normal in waters of Okatibbee Lake.
Conductance of surface waters depends on the total concentration of soluble
ions since tllis parameter measures how well a surface water conducts an electrical current.
Conductance is eh1Jressed as pmhos/cm 3 . It is useful in fisheries
management in detecting changes in certain soluble elements in the water.
Okatibbee Lake conductance ranged from 125 to 20 ,ll.1l1.hos/cm3 .
22
In
3-B-6.
Plant nutrients.
3-B-6-a. Nutrient enrichment in impoundments. The surface runoff in a stream basin is both the solvent and the transporting vehicle for more than
15 elements that are essential nutrients in the growth of aquatic plants and animals.
The concentration of these elements in runoff water and eventually in river water
depends not only upon the type of soils and agricultural operations that occur in
the drainage area, but also upon the amounts of domestic sewage and industrial
effluents that may be discharged there.
Once the nutrients reach the impoundment various things can happen.
the nutrients in the lake will always be present in soluble form.
Some of
These soluble
nutrients may origtnate either from re-solution of bottom muds or from waste
and decomposition of plants and animals. Another portion of the nutrients may
be precipitated as colloidal matter directly into the bottom muds for temporary or
permanent storage.
Yet another part of the input nutrients may be used in the
growth and reproduction of bacteria, ftmgi, algae, or rooted aquatic plants. These
plants may be consumed by some animals, or the plants may die and deposit their
nutrients in the muds.
Animals eliminate most of the nutrients they consume as waste, retaining
only a small portion in their growth.
The growth retained portion of nutrients may
be removed from the local enviromnent if the animal flies, walks, crawls, or is
taken bodily from the impoundment. If the animal remains in the impoundment, it
eventually dies. Then the nutrients return to bottom muds or become a food item
for another animal.
23
A portion of the input nutrients passes out of the impoundment into the tailwaters and are then classified as outlet nutrients.
These outlet nutrients may
occur in soluble forms, bacteria, flmgi, algae, rooted plants, animals, other
organic materials, and soil colloids. All of these nutrients move downstream to
combine with additional rtmoff and eventually become the input nutrients for the
next impoundment. There the process is repeated and so on until the river flows
into the ocean.
What has been described above is an abbreviated nutrient cycle for an impoundment.
In order for man to use this cycle to his advantage it is necessary
to know both the quantity of each nutrient found in each of the niches described
and the rate of partial or permanent retention.
With such information available
it is possible to determine the element or elements responsible for overproduction
of noxious plants, isolate the source(s), and eventually correct the problem.
Since the nutrient cycle of an impolmdment is intimately related to eutrophication, and since a moderate degree of nutrient enrichment is essential for fish
production in impolmdments, tolerable eutrophication is beneficial. In those cases
where there are excessive amollnts of nutrients, seasonal rooted aquatic plants
may be used as possible nutrient retention sites during periods of hot weather and
low flow.
Cold weather and frost then provides a mechanism for the slow release
of nutrients when there is a greater rate of stream flow.
Since elemental nutrients are essential to aquatic life, it is necessary to know
how they are distributed in the water, suspended matter (living and dead, organic
24
and inorganic), bottom soils, plants, and fish.
Only with this knowledge is it
possible to fully evaluate an aquatic habitat.
3-B-6-b.
Macro-nutrients. All living things are composed of
elements that are arranged in different combinations and configurations to form
matter.
Those elements which are most abundant in living tissues are called
macro-nutrients or major elements.
Macro-nutrients include carbon, hydrogen,
oxygen, nitrogen, phosphorus, sulfur, potassium, magnesium, calcium, and
sodium. The concentrations of macro-nutrients in various aquatic components
of Okatibbee Lake are shown in Table 3.
Using the mean flow data on the Okatibbee Creek at the Dam and taking the
average total nitrogen and total phosphorus concentrations at the lower end of the
lake, the total daily output of these nutrients was calculated for Okatibbee Lake.
The estimated daily discharge per square mile of drainage area was 2.3 pounds
of nitrogen and less than 0.01 pOlmds of phosphorus.
The estimated standing crop
of soluble nitrogen and phosphorus in Okatibbee Lake was 14.2 and 0.03 pounds
per acre respectively.
3-B-6-c.
Micro-nutrients.
In addition to the major nutrients men-
tioned above, all living things require minute quantities of other elements in order
to survive. Because only a limited quantity of each element is required, they are
called micro-nutrients. Among the micro-nutrients are iron, manganese, copper,
zinc·, molybdenum, vanadium, boron, chlorine, and cobalt.
There are undoubtedly
several other elements which eventually will be added to this list, but at present
25
Table 3. Average concentrations of macro-nutrients (elements) in filtered water,
suspended matter, bottom soils, and fish from Okatibbee Lake.
Suspended
matter, ppm
Bottom
soil, ppm
Fish
ppm
Macronutrients
Filtered
water, ppm
Nitrogen
.896
Phosphorus
.01
Potassium
1. 36
.119
610
23,144
Magnesium
5.96
.025
480
3,746
Calcimll
4.53
.001
1,510
11,896
Sodimn
14.82
.067
320
9,580
285
26
these are the only ones whose active role in living organisms is known.
The
micro-nutrient concentrations fOlmd in the various components of Okatibbee Lake
are given in Table 4.
3-B-6-d.
Nutrient sources. All of the nutrients entering Okatibbee
Lake come from one of the following sources: the atmosphere, domestic sewage
animal production refuse, animal and plant processing wastes, fertilizer and
chemical manufacturing spillage, other industrial effluents, and agricultural nmoff.
The discussion here is concerned with the carbon, nitrogen, and phosphorus
that enters the system.
In pond cultm'e it has been demonstrated that water, like land, must be properly
fertilized to produce a sustained high yield of fish.
Likewise, large impoundments
must have a continuous supply of nutrients in order to produce food for fish.
Unforhmately, large impoundments have um'egulated nutrient supplies and in
some instances have become so over-fertilized that they produce noxious plant
growths. To date, even though the supply of nitrogen and phosphorus in Okatibbee
Lake has been moderate for phytoplankton production, other factors (namely excessive flow, tm'bidity, and wind action) have prevented such a growth from
developing.
Dissolved carbon is known to be a limiting factor in the development of phytoplankton growths in runoff waters from Piedmont Province soils. Runoff waters
from Coastal Plain soils are also poor sources of dissolved carbon.
During its
first years of impomldment Okatibbee Lake might have received a considerable
27
Table 4. Average concentrations of micro-nutrients (elements) in filtered water,
suspended matter, bottom soil, and fish from Okatibbee Lake.
Micro-
Filtered
water, ppm
Suspended
matter, ppm
Bottom
soil, ppm
Fish
ppm
Iron
.167
.341
220
274.6
Manganese
.160
.046
194
838
Copper
.012
.021
10
12.4
Zinc
.064
.014
110
175.8
Cobalt
.012
.0001
20
9.4
28
quantity of dissolved carbon from decomposition of plant refuse on its bottom.
This source has been depleted and now the only source is that naturally produced
on the drainage area.
3-B-7. Toxic substances.
For many years researchers have recognized
that a number of chemical compolmds, alone or in combination with other compounds,
were toxic to fish at low concentrations.
For a long time it was impossible to
identify exact causative toxicants because of inadequate analytical techniques.
In the past decade, however, there have been some outstanding break-throughs in
analytical equipment and now it is possible to detect and identify most of the
pollutants in water.
This has permitted rapid strides to be made in the control
of toxic substances.
Only two major groupings of toxicants are known to be present in the Okatibbee
Creek system.
These groups are pesticides
3-B-7-a.
Pesticides.
and heavy metals.
Pesticides, products of modern organic
chemistry, were not known prior to World War II. Since that time the efficacy
of most insecticides, bacteriacides, fung'icides, and herbicides has created an
enormous market for these products.
Unfortunately, some of the compounds are
quite toxic to fish and others are very persistent in either their original or analog
form.
Techniques of application have been devised to minimize the risk of those
pesticides which are toxic to fish, but a few compounds have been ballied from use.
In the case of persistent pesticides which accumulate in fish tissues,
29
although their detrimental effects upon fish production is questionable, many
persons assume such pesticides constitute a hazard to human health.
Consequently,
there now are strict regulations concerning the use of pesticides, particularly in
aquatic areas.
Needless to say, many vector and aquatic weed control practices
on large impoLmdments have been altered.
The amounts of pesticides in fish from Okatibbee Lake are unknown.
3-B-7-b.
Heavy metals. There are a number of metallic elements
sLLch as lead, zinc, mercury, chromium, cadmium, nickel, and copper that are
considered either essential or tolerable constituents of aqLLatic life when fOLLnd
in limited quantities.
In large amounts, however, these metals may be either
toxic or accumulative in aquatic organisms.
Unfortunately, our knowledge of
the natural occurrence of these elements in water is limited, and so their true
effects upon the envirOlmlent remain to be determined.
Data on the amount of
these elements found in the various components of the Okatibbee Lake aqLLatic
habitat are given in Table 5.
3-B-7-c.
Industrial toxicants.
3-B-8. Sediment load.
None are known.
The sediment load transported by nmoff waters
depends LLpon several factors in the watershed. These factors inclLLde slope of
the land, soil type, qLLantity and type of land cover, amount of construction on the
watershed, and ore-washing procedures used at strip mines.
In addition, the
seasonal rate and duration of rainfall in the drainage area influence the sediment
load of runoff waters.
30
Table 5. Average concentrations of heavy metal elements in filtered water, suspended
matter, bottom soil, and fish from Okatibbee Lake.
Metallic
elements
Filtered
water, ppm
Suspended
matter, ppm
Bottom
soil, ppm
Fish
ppm
0
.022
20
8.6
Chromium
.023
.016
46
28.8
Cadmimn
.007
.008
8
9.2
Nickel
.006
.026
0
22.6
Lead
31
The Okatibbee Creek drainage area occupies a topographic region consisting
of very low hills and rather broad valleys. The soils within this region are typical
Red Hill derivatives that are erosive.
Since these soils are sandy clays, the silt
loading of runoff waters is partially of a colloidal nature.
on the Okatibbee Creek varies from 5 to 25+JTU's.
The current turbidity
Maximum loading occurs two
or three times a year in the winter and early spring.
3-C.
Pollution sources.
These sources are identical to the nutrient em'ich-
ment sources listed in Section 3-B-6-d. As a matter of record, no point sources
of waste disposal on the Okatibbee Creek above Okatibbee Dam are of sufficient
size to warrant inclusion in any published report.
The fact that very limited agricultural pollution enters Okatibbee Lake accounts
in part for the absence of soluble phosphorus in the lake waters.
32
4. Aquatic Plants in the Impoundment.
4-A. Aquatic plants - definition.
The term "aquatic plant", as used in this
Plan, refers to a multitude of plant species (including some bacteria and fungi)
whose entire life cycie is passed within an aquatic environment.
Practically all aquatic plants may be desirable at one time or another in a
particular habitat.
However, when they become too dense or interfere with other
uses of the water, they become a nuisance.
4-B.
Factors affecting aquatic plant growth. Bodies of water are like land
areas in that some type of vegetation will occupy any suitable habitat.
Likewise,
the more ablmdant the nutrient supply, the more dense the vegetation, other environmental factors being favorable. All nutrients essential for plant growth are
yet to be determined.
Some of the elements lmown to be important are nitrogen (N),
phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn),
iron (Fe), silicon (Si) for diatoms, sulfur (S) as sulfates, oxygen (02)' and carbon
(C) as carbonates.
In many habitats an abundance of nitrogen and phosphorus
promotes vegetative production if other conditions for growth are favorable.
Most
algae also require some simple organic compounds, such as amino acids and
vitamins, and many trace elements, such as zinc and copper.
It must be remembered that factors other than plant nutrients also are opera-
tive in the establishment and maintenance of aquatic plant growths.
For the process
of photosynthesis to occur, there must be sufficient light reaching the critical point
in the habitat. If turbidity from muds, dyes, other materials, or even phytoplankton
33
is too great, plants at lower depths cannot grow. However, these same plants if
established in an area, can trap large amounts of intermittent silt and other materials, and clear the water for downstream use.
Another factor that might be operative in preventing aquatic plant growth
would be the lack of free CO 2 and bicarbonate ions in a particular aquatic environment.
Certainly an area in which the pH is high, 9.5 or above, or low, below
5.5, productivity would not reach high levels due to a lack of sufficient bicarbonates.
Temperature also is an important factor in determining the amount of growth.
For each species there is an optimum range of temperatures in which the greatest
growth occurs.
Wave action on large expanses of water may also be a factor in regulating all
types of aqua tic plant growths. This appears contradictory to the concept that
winds cause mixing of surface and bottom waters, thereby renewing plant nutrients
in the euphotic zone.
However, in certain lakes and reservoirs, wind induced waves
and currents mechanically agitate bottom materials and waters to an extent that
interferes with the production of phytoplankton and rooted aquatic plants.
4-C.
Aquatic plant groups and associated habitat problems.
The plants that
occupy an aquatic habitat may be divided into bacteria, fungi, algae, and rooted
or floating flowering plants.
In the paragraphs which follow there is a brief
summary of the characteristics of each plant group and the problems the plants
may create.
34
4-C-1. Bacteria.
Members of the group of sheath-formers are the
primary bacterial nuisances in rivers, lakes, and ponds. A notable problem
associated with this group occurs in the areas subjected to organic em"ichment.
Bacteria, especially of the genus Sphaerotilus are prevalent in areas receiving
raw domestic sewage or improperly stabilized paper pulp effluents containing a
small amount of simple sugars. The bacterial growths interfere with fishing by
fouling lines, clogging nets, and generally creating unsightly conditions in an infested area.
Their metabolic demands while living and their decomposition after
death also cause the bacteria to impose a high BOD load on the stream, which can
severely deplete dissolved oxygen.
Furthermore, it has been reported that large
populations of Sphaerotilus render the habitat noxious to animals and thus actively
exclude desirable fish and invertebrates.
No known growths of Sphaerotilus were present in Okatibbee Lake during 1973.
4-C-2.
Fungi.
4-C-3. Algae.
size, and habitat.
No information.
The freshwater algae are quite diverse in shape, color,
In fact, describing all the species of algae would be as compre-
hensive as writing about all the land plants, including fungi, mosses, ferns, and
seed plants.
Algae may be free-floating (planktonic) or attached to the substrate (benthic or
epiphytic types).
They may be macroscopic or microscopic and are single-celled,
colonial, or filamentous.
When present in sufficient numbers, these plants im-
35
part color to the water, varying from green to yellow to red to black.
They may
also congregate at or near the water surface and form a scum or waterbloom.
Algae form the first link in the aquatic chain which converts inorganic constituents in the water into organic matter.
During daylight hours algae photosynthe-
size, thus removing carbon dioxide from the water and producing oxygen.
also produce carbon dioxide by their continual respiration.
Algae
The amolmts of oxygen
produced by algae during active photosynthesis is generally in excess of the amount
of carbon dioxide released by respiration.
Limited concentrations of algae are not troublesome in surface waters, but
an overabundance of various species is undesirable for many water uses.
A rela-
tively abundant growth of phytoplankton in waters 3 or more feet deep shades the
bottom muds enough to prevent germination of seed and halt the growth of practically all rooted submersed and emersed aquatics.
This removes an important
source of food for ducks and other waterfowl.
Some green algae, blue-green algae, and diatoms produce odors and SCunlS
that make waters less desirable for swimming. Also, people who are allergic to
many species of algae are affected if the algae become very numerous in waters
used for swimming.
Dense growths of such phytoplankton and filamentous algae may limit photosynthetic activity to a surface layer only a few inches deep.
Under certain condi-
tions, the population of algae may die and their decomposition will deplete dissolved
oxygen in the entire body of water.
36
A number of algal species reportedly cause gastric disturbances in humans
who consume the infested water.
Under certain conditions several of the blue-
gTeen algae produce toxic organic substances that kill fish, birds, and domestic
animals.
The g'enera that contain species which may produce toxins are Anabaena,
Anacystis, Aphanizomenon, Coelosphaerium, Gloeotrichia, Nodularia, and Nostoc.
Species of the green algae, Chlorella, have also caused toxicosis.
Many forms of phytoplankton and filamentous algae clog sand filters in water
treatment plants, produce lmdesirable tastes and odors in drinking water, and
secrete oily substances that interfere with manufacturing processes and domestic
water use.
Certain algae cause foaming of water during heating, corrosion of
metals, or clogging of screens, filters or piping. Algae may also coat cooling
towers and condensers, causing these units to become ineffective.
Filamentous algae in ponds, lakes and reservoirs may deplete the nutrient
supply of the unicellular algae which are more commonly eaten by fish and fishfood organisms. Dense growths of filamentous algae may also reduce total fish
production and seriously interfere with harvesting the fish by hook and line, seining,
or draining.
Under certain conditions, these growths on pond and lake bottoms
become so dense they eliminate fish spawning' areas and possibly interfere with
the production of invertebrate fish food.
However, the amount of cover prOVided
by such large growths of filamentous algae can contribute to enormous population
increases, resulting in large muubers of small, stlmted fish.
A listing of the various genera of algae collected from Okatibbee Lake is given
in Table 6.
37
Table 6.
List of phytoplankton genera found in Okatibbee Lake in 1974.
Chlorophyta (Green Algae)
Asterionella
AnJdstrodesmus
Chlamydomonas
Chlorella
Coelastrulll
Cosmarium
Hormidium
Pediastrum
Sphaerocystis
staurastrum
Ulothrix
Euglenophyta (Euglcnoids)
Coccomonas
Euglena
Lepocinclis
Phacus
Trachelolllonas
Chrysophyta (Yellow-green Algae)
Lagynion
Mallomonas
Unidentified diatoms
Cyanophyta (Blue-green Algae)
Anabaena
Aphanocapsa
Merislllopedia
Pyrrhophyta (Dinoflagellates)
Glenodinilllll
Peridinium
38
4-C-4.
Flowering plants.
floating, and marginal plants.
This group includes submersed, emersed,
These aquatics may be rooted in the soil or they
may have roots which float at or near the water surface.
Submersed plants are those which produce most or all of their vegetation
beneath the water surface.
These plants often have an underwater leaf form totally
difi'lrent from the floating or emersed leaf form.
aerial stalk.
The flowers usually grow on an
The ablmdance of these weeds depends upon the depth and turbidity
of the water and also upon the type of bottom.
In clear water 8 to 10 feet is the
maximum depth of their habitat, since they must receive enough light for photosynthesis when they are seedlings.
Most of these submersed aquatics appear
capable of absorbing nutrients and herbicides through either their roots or their
vegetative growth.
Emersed plants are rooted in bottom muds, but produce most of their vegetation at or above the water surface.
Some species have leaves that are flat and
float entirely upon the surface of the water.
Other species have saucer-shaped
or irregular leaves which do not float entirely upon the water sill'face.
Marginal plants are probably the most widely distributed of the rooted aquatic
plants and are quite varied in size, shape, and habitat.
both in moist soils and in water up to 2 feet deep.
Many species can grow
Other species grow only in
moist soils or only in a water habitat.
Floating plants have true roots and leaves, but instead of being anchored in
the soil they float about on the water surface.
39
The plants are buoyant due to modi-
fications of the petiole and the leaf, including the covering of the leaf surface.
Most species have well-developed root systems which collect nutrients from the
water.
Species designated as weeds are not necessarily such in all places and at all
times.
For example, many submersed and emersed plants that normally inter-
fere with water recreation are considered desirable food sources in waterfowl
refuges. Rooted plants with floating leaves (e. g., waterlilies and watershield) and
those plants which float upon the surface (e. g., waterhyacinth, parrotfeather,
alligatorweed, and duckweeds) are considered highly objectionable by many
water users.
However, in clear water areas where artificial or natural fertiliza-
tion is moderate, removal of these surface-shading plants permits sunlight to
penetrate to the bottom muds and thus submersed plants may soon occupy these
waters.
These submersed plants generally are considered more objectionable
than the original surface-covering plants.
Most emersed and marginal plants and a few submersed plants and filamentous
algae provide a suitable habitat for the development of anopheline and other pest
mosquitoes.
They also furnish a hiding place for snakes and are an excellent
habitat for damselflies and some aquatic beetles.
Like filamentous algae, flowering plants consume nutrients that could otherwise be used by phytoplankton.
Thus an overabundance of rooted plants may re-
duce total fish production in an infested body of water and interfere with harvesting
the fish.
There is also evidence that rank growths of submersed, emersed, or
40
floating plants may deplete the dissolved oxygen supply in shallow waters.
This
causes fish to move into more open and better quality water, if such water is
available.
Extensive growths of weeds can, however, provide so much cover
that the fish population increases enormously, resulting in overcrowding and
shmting.
A listing of the flowering aquatic plants for Okatibbee Lake is given in Table 7.
4-D. Aquatic plant populations on Okatibbee Lake and methods for their control.
As stated above, there are no growths of troublesome aquatic plants on Okatibbee
Lake at the present time.
It is doubtful that any problems with aquatic plants will
develop on this lake so long as present operational procedures are in effect.
41
Table 7.
List of flowering aquatic plants along the shoreline of Okatibbee
Lake, October, 1973.
Gramineae
Eragrostis hypnoides
Leersia oryzoides
Panicum agTostoides
Panicum dichotomiflorum
lovegrass
rice cutgrass
redtop panicum
fall panicum
Cyperaceae
Cyperus erythrorhizos
Cyperus iria
Cyperus pseudovegetus
Cyperus strigosus
Eleocharis obtusa
Eleocharis tuberculosa
Fimbristylis autumnalis
Fimbristylis miliacea
Fimbristylis tomentosa
redroot flats edge
rice flatsedge
flatsedge
false nuts edge
bunt spikeru sh
spikerush
slender fimbristylis
fimbristylis
fimbristylis
Polygonaceae
Polygonum pensyl vanicum
Pennsylvania smartweed
Unbelliferae
Eryngium prostratum
eryngo
Scrophulariaceae
Lindernia dubia
false pimpernel
Compositae
Bidens frondosa
devil's beggarticks
42
5.
Description of the Fisheries.
Throughout the time this impotmdment has existed, studies have been cond lcted
to determine the species of fish present, the abtmdance of each species in the total
catch, the condition of individuals of each species, and the prevalence of disease
and parasite infestations.
The available information on each of these aspects of
Okatibbee Lake is summarized in this Section.
Most of the information presented
in this Plan was collected between 1971 and 1974.
No pre-impoundment data on the
fish population in the stretch of stream within Okatibbee Lake are available for
comparative purposes.
5-A.
Warmwater species of fish in Okatibbee Lake.
The earliest collections
of freshwater fishes from Pascagoula River system were made in the 1880's.
Since
that time several ichthyologists have collected in this area and have added to the total
list of species that have existed in this stretch of the river.
These findings were
slUllmarized in 1959 (Cook) and a checklist of known and doubtful species that
currently exist was prepared.
The warmwater species comprising this list were
divided into three gTOUpS: sport, commercial, and miscellaneous as presented in
Table 8.
5-B.
Coldwater species of fish in Okatibbee Lake.
None.
5-C.
Downstream species from Okatibbee Lake. According to the best infor-
mation available the same species of fish exist in the tailwaters of Okatibbee Dam
that exist in Okatibbee Lake.
43
Table 8.
A check list of warmwater fish species believed to be present in the
Pascagoula River, separated into game, commercial, and other
groupings. *
Game Species
Redfin pickerel
Esox americanus
Chain pickerel
Esox nio-er
-=
White bass
Morone chrysops
Striped bass (introduced 1972)
Morone saxatilis
Rock bass
Ambloplites rupestris
Flier
Centrarchus macropterus
Warmouth
Chaenobryttus gulosus
Green sunfish
Lepomis cyanellus
Orangespotted sunfish
Lepomis humilis
Bluegill
Lep0mls macrochirus
Dollar sunfish
Lepomis marginatus
Longear sunfish
Lepomis megalotis
Red-ear sLmfish
Lepomis microlophus
Spotted sunfish
Lepomis punctatus
Spotted bas s
Micropterus punctulatus
Largemouth bass
Micropterus salmoides
White crappie
Pomoxis annular is
Black crappie
Pomoxis nigromaculatlls
44
Table
8, cont'd.
Commercial Species
Atlantic sturgeon
Acipenser oxyrhynchus
Paddlefish
Polyodon spathula
American eel
Anguilla rostrata
Carp
Cyprinus carpio
Ri vel' carpsucker
Carpiodes carpio
Quillback carpsucker
Carpiodes cyprinus
Highfin carpsucker
Carpiodes velifer
Blue sucker
Cycleptus elongatus
Creek chubsucker
Erimyzon oblongus
Sharpfin chubs ucker
Erimyzon tenuis
Northern hogsucker
Hypentelium nigricans
Smallmouth buffalo
Ictiobus bubalus
Bigmouth buffalo
[ctiobus cyprinellus
Spotted sucker
Minytrema melanops
Black redhorse
Moxostoma dUCluesnei
Golden redhorse
Moxostoma erythrurum
Blacktail redhorse
Moxostoma poecilurum
Black bullhead
[ctalurus melas
Yellow bullhead
[ctalurus natalis
Brown bullhead
Ictalurus nebulosus
45
Table
8, cont'd.
Commercial Species cont'd.
Channel catfish
Ictalurus plUlctatus
Flathead catfish
Pvlodictis olivaris
Other Species
Least brook lamprey
Lampetra aepyptera
Spotted gar
Lepisosteus oculatus
Longnose gar
Lepisosteus osseus
Shortnose gar
Lepisosteus platostomus
Alligator gar
Lepisosteus spatula
Bowfin
Amia calva
---
Skipjack herring
Alosa chrysochloris
Gizzard shad
Dorosoma cepedianum
Threadfin shad
Dorosoma petenense
Goldeneye
Hiodon alosoides
Mooneye
Hiodon terg-isus
Stoneroller
Campostoma anomalum
Goldfish
Carassius auratus
Silver jaw minnow
Ericymba buccata
Cypress minnow
Hybognathus hayi
Silvery minnow
Hybog-nathus nuchalis
Speckled chub
Hybopsis aestivalis
46
Table
8, cont'd.
other Species cont'd.
Pirate perch
Aphredoderlls sayanlls
Blackstripe topminnow
Ftmdullls notatus
starhead topminnow
Fund ulus notti
Blackspotted topminnow
Fundulus olivaceous
Mosquitofish
Gambusia affinis
Brook silverside
Labidesthes sicculus
Mississippi silvers ide
Menidia audeus
Banded pygmy sunfish
Elasoma zonatum
Naked sand darter
Ammocrypta beani
Scaly sand darter
Ammocrypta vivax
Blllntnose darter
Etheostoma chlorosomum
Johnny darter
Etheostoma nigrunl
Goldstripe darter
Etheostoma parvipinne
Speckled darter
Etheostoma stigmaeum
Gulf darter
Etheostoma swaini
Redfin darter
Etheostoma whipplei
Banded darter
Etheostoma zonale
Logperch
Percina caprodes
Blackside darter
Percina maculata
Blackbanded darter
Perc ina nigrofasciata
47
Table
8, cont'd.
other Species cont'd.
Dusky c1arter
Perc ina sciera
Stargazing darter
Percina uranidea
Freshwater drum
Aplodinotus grunniens
* Data from
Fannye A. Cook, Freshwater Fishes in Mississippi (1959).
48
5-D. Rare and endangered species.
The Mississippi Game and Fish Commis-
sion has prepared a list of those species of fish that might be rare or endangered in
the surface waters of their State.
While the Okatibbee Creek, in the stretch above
Okatibbee Dam, may contain some rare species there are none that currently can
he expected to be endangered.
5-E.
Fish-food organisms.
In 1966-67 a biological survey was made of the
Okatibbee Creek basin by the Fisheries Division of Mississippi Game and Fish
Commission.
This study included the segment of the Creek immediately down-
stream from Okatibbee damsite.
A total of 44 different aquatic organisms were
found (Table 9) of which ten were classified as intolerant forms.
5-F.
History of parasite and disease incidents in fish populations.
Throughout
the history of Okatibbee Lake impoundment there have been incidents of fish mortality when all water quality parameter s have been satisfactory for fish to grow ani
reproduce.
One major cause of warm weather fish kills has been a bacterial infec-
tion caused by the group called Aeromonas.
Generally this type of infection is
recognized by the large, red, boil-like lesions on the body of the fish.
Three factors, operative in the springtime, tend to incite the spread of both
parasite and disease infections.
One factor is a rising water temperature, that
prOVides the optimum parasite and disease development range (65 to 75 0 F). A
second factor is that this temperature range is the same that stimulates fish spawning
and many species of sunfishes and bass are congregated and seeking nesting sites.
This results in crowding of fish into a restricted area and much physical contact
49
Table 9.
Macroinvertebrates collected from the Okatibbee Lake area in 1967.
Plesioposa
Lumbriculidae
Tubificidae
Limnodrilus
Amphipoda
Gammaridae
Gammarus
Decapoda
Cambaridae
Isopoc1a
Asellic1ae
Asselus militaris
Coleoptera
Elmidae
Dryopidae
Pelonomus
Dytiscidae
Hydroporus
Gyrinic1ae
Dineutus
Hyc1roohilidae
Berosus
Diptera
Ce r atopogonic1ae
Tenc1ipedic1ae
Clinotanypus
Hyc1 r obaenus
Pentaneura monilis
Polypedilum
Pseuc1ochironomus
Spaniotoma
Tanypus
Tanytarsus
Tendipes (cryptochironomus) sp.
Tendipes (Cryptochironomus) sp. B
Tendipes (cryptochironomus) ~
50
*
Table 9,
cont'd.
Diptera (cont'd)
Tendipedidae (cont'd)
Tendipes (Dicrotendipes) neomodestns
Tendipes (Endochironomusl nigricans
Tendipes (Tendipes) attenuatns
Ephemeroptera
Bactidae
Isonychia
Caenidae
Caenis
Ephemeridae
Hexagenia limbata
Heptagenidae
Stenonema ares
Stenonema bipunetatnm
Stenonema sp.
Odonata
Agrionidae
Argia
Gomphidae
Dromogomphus
Hagenius
Gomphus
Progomphus
Plecoptera
Perlidae
Perlesta
Trichoptera
Hydroptilidae
Oxethira
Psychomyiidae
Polycentropus
En lamellibranchiata
Sphaeriidae
Pisidium
Sphaerium stamineum
Gastropoda (Class)
* Mississippi
Game and Fish Commission 5 1
between individuals.
Such a situation provides ideal conditions for the spread of
infections. Another factor is that fish are in their poorest condition during early
spring, making them more susceptible to disease and parasite attacks.
Current trends in disease and parasite infections in lakes of the Southeastern
United States indicate that infections are generally more prevalent during warm
months, but may occur in varying degrees throughout the year.
Also, it has been
noted that under certain conditions the spread of infections in a large impOlmdment
may intensify over a period of several years.
The probable disease organisms that are present on fish in the Okatibbee Creek
area are presented in Tables 10 and 11.
Needless to say, the loss of mostly harvestable-sized fish to disease and parasite infections is lmdesirable, nevertheless it indicates that considerably more
harvestable-sized fish were present than were being taken by the fishermen.
To
date, no satisfactory treatment has been devised that could be used to combat the
spreading of disease and parasite infections among' the fishes in Okatibbee Lake.
5-G. History of fish kills.
During the existence of Okatibbee Lake there have
been no reports of fish kills other than those caused by disease and parasite infections.
5-H.
Establishment of Okatibbee Lake fishery including flooding schedule.
The origin of the freshwater fishery in Okatibbee Lake was the fish population
inhabiting the Okatibbee Creek at the time the dam was closed. As the waters in
this impolmded portion of the stream rose they flooded a broad flood plain.
This
provided increased enrichment as well as increased surface area for fish-food
52
Table 10.
1.
Probable fish parasites in the Pascagoula River Basin.
Amiidae
Cestoda
Haplobothrium
Proteocephalus
Acanthocephala
Neoechinorhynchus
11.
111.
Anguillidae
Crustacea
Ergasilus
Catostomidae-
Fungi
Saprolegnia
Protozoa
Glossatella
Myxobilus
Myxosoma
Trematoda
Anoncohaptor
Aplodiscus
Dactylogyrus
Gyrodactylus
Myzotrema
Octomacrulll
Pellucidhaptor
Pseudomurraytrema
Triganodistolllulll
Cestoda
Biacetabulum
Isoblaridacris
Monobothrium
Proteocephalus
Nematoda
Capillaria
Philometra
Spinitectus
53
Table 10 (cont'd.)
III.
(cont'd.)
Acanthocephala
A canthocephalus
Neoechinorhynchus
Pilum
Leech
Piscicolaria
Placobdella
Crustacea
Argulus
Ergasilus
IV.
Centrarchidae
Fungi
Saprolegnia
Protozoa
Epistylis
Myxobilatus
Trichodina
Myxosoma
Glossatella
Myxidium
Trematoda
Actinocleicllls
Anchoradiscus
ClavunclllllS
Crepiclostomum
Cryptogonimus
Gyroclactylus
Lyrodiscus
NeasClls
Phyllodistomllm
Pisciamphistoma
PosthocliplostOIDllID
Urocleiclus
CleiclodisClls
Uvelifer
Lellcerutherlls
ClinostoIDllm
54
Table 10 (cont'd.)
N.
(cont'd.)
Cestoda
Bothriocephalus
Haplobothrium
Proteocephalus
Nematoda
Camallanus
Capillaria
Contracaecum
Hedruris
Philometra
Spinitectus
Spiroxys
Acanthocephala
A canthocephalus
Eocollis
Leptorhynchoides
Neoechinorhynchus
Pilum
Pomphyrhynchus
Leech
Cystobranchus
Illinobc1ella
Pisciolaria
Crustacea
Ergasilus
Aetheres
Lernea
Mollusca
Glochic1ium
V.
Clupeic1ae
Protozoa
Ichthyophthirius
Plistophora
Trichoc1ina
Scyphidia
55
Table 10 (cont'd.)
V.
(cont'd.)
Trematoda
Pseudoanthocotyloides
Mazocraoides
Cestoda
Bothriocephalus
Nematoda
Capillaria
Hedruris
Acanthocephala
Gracilisentis
Tanaorhamphus
Crustacea
Ergasilus
VI.
Cyprinidae
Protozoa
Epistylis
Glossatella
Ichthyophthirius
Myxobilatus
Myxosoma
Trichodina
Scyphidia
Trematoda
A lloglossidium
Crepidostomum
Dactylogyrus
Gyrodactylus
Neascus
Posthodiplostomum
Pseudacolpenteron
Cestoda
Atraetolytocestus
Biacetabulum
Khawia
Penarchigetes
Proteoecephalus
56
Table 10 (cont'd.)
VI.
(cont'd.)
Nematoda
Rhabdochona
Leech
Placobdella
Crustacea
Argulus
Ergasilus
Lernaea
Mollusca
Glochidia
VII.
Esocidae
Trematoda
Crepidostomum
Cestoda
Proteocephalus
Nematoda
Hedruris
Philometra
Rhabdochona
Acanthocephala
Neoechinorhynchus
Pilum
Crustacea
Ergasilus
Lernaea
VIII.
Ictaluridae
Fungi
Saprolegnia
Protozoa
Chilodon
Costia
Glossatella
I-Iennegllya
Ichthyophthirills
57
Table 10 (cont'd.)
VIII.
(cont'd.)
Protozoa (cont'd.)
Scyphidia
Trichodina
Trichophrya
Trematoda
Alloglossidium
Cleidodiscus
Clinostomum
Gyrodactylus
Phyllodistomum
Posthodiplostomum
Cestoda
Corrallobothrium
Nematoda
Contracaecum
Raphidascaris
Spinitectus
Acanthocephala
Neoechinorhynchus
Leech
Cystobranchus
Crustacea
Achtheres
Argulus
Ergasilus
Lernaea
IX.
Lepisosteidae
Trematoda
Didymozeidae
Cestoda
Proteocephalus
Nematoda
Hedruris
58
Table 10, cont'd.
IX.
X.
cont'd
Crustacea
Argulus
Ergasilu8
Polyodontidae
Trematoda
Diclybothrium
Cestoda
Marsipometra
Nematoda
Camallanus
Crustacea
Ergasilus
Xl.
Sciaenidae
Trematoda
Crepidostomum
Alloglossic1ium
Nematoda
Contracaecum
Cystidicola
Crustacea
Ergasilus
Lernaea
Mollusca
Glochic1ia
59
Table 11.
Viral, bacterial and fungal diseases of
l~eservoir
fish *
Catostomidae
Viruses - None
Bacteria
Aero111onas liquefaciens (Syn. :.A. hydrophila, A. -punctata)
Pseudomonas fluorescens
Chondrococcus colunlnaris
Fungi
Saprolegnia
Achlya
Centrarchidae
Viruses
Lymphocystis
Bacteria
Aeromonas liguefaciens (Syn, : A. hydrophila, A. pUllctata)
Pseudolnonas flourescens
Chondrococcus colulllllaris
Fungi
Saprolegnia
Achlya
B ranchiomyces
Clupeidae
Viruses - None
Bacteria
Aeromonas liguefaciens (Syn. : ~ hydrophila, A. punctata).
Pseudolnonas flourescens
Chondrococcus colulllnaris
Fungi
Saprolegnia
Achlya
60
Table 11 (Cont'd).
Cyprinidae
Viruses - None
Bacteria
Aeromonas liquefaciens (Syn. :A. hydrophila. A. punctata)
Pseudonl0nas fluorescens
Chondrococcus colunlnaris
Fungi
Saprolegnia
Achlya
Esocidae
Viruses - None
Bacteria
Aeromonas liquefaciens (Syn. : A. hydrophila, A. punctata)
Pseudol11onas fluorescens
Chondrococcus columnaris
Fungi
Saprolegnia
Achlya
Brachiomyces
Ictaluridae
Viruses
Channel catfish virus (has not been found in reservoirs)
Bacteria
Aerol11onas liquefaciens (Syn. : A. hydrophila,
Pseudomonas fluorescens
Chondrococcus colunularis
Jl.
p""unctata)
Fungi
Sapro1egnia
Achlya
* Information
from Dr. John A. Plumb, Auburn University Department of Fisheries
and Allied Aquacultures.
61
development.
The fish population expanded with this increased water area and
abundant food supply.
The reservoir started filling in the fall of 1968.
During the spring of 1969
this newly filled reservoir was stocked with the following nunlbers and kinds of fish:
503,000
40,000
149,000
1,289
bluegill fingerlings
red-ear fingerlings
largemouth bass fry
striped bass fingerlings
In 1970 the following stocking was made to the lake:
1,000 striped bass fingerlings
In 1971 the lake was stocked with the fish listed below.
12,000 striped bass
The 1972 and 1973 stockings of fish into Okatibbee Lake were as follows:
35,000 and 20,000 striped bass respectively
In the spring of 1974, following the shad thinning program started in the fall of
1973, the following numbers and kinds of fish were stocked into Okatibbee Lake:
61,500
24,000
40,000
73
7,800
striped bass fingerlings
Florida largemouth bass
largemouth bass
largemouth bass (brood fish)
threadfin shad (brood fish)
From 1969 to the present the water level has fluctuated annually according to
the schedule prescribed for flood control. This fluctuation has undoubtedly concentrated the smaller fishes and made them more vulnerable to bass predation.
It has also temporarily deprived the sunfishes of some 1,080 acres of food producing boLtom areas.
62
5-1.
Historv of species composition, relative abundance, and condition within
each species including methods used to obtain fish samples.
One of the major
problems that has confronted fisheries biologists has been the lack of techniques
to accurately estimate the population of fish that exist in large impoundments.
To
date, the estimates that are available in various publications and in biologists'
files are open to criticism, but no one can say that they are LUlreliable.
In large
ponds and small lakes it is usually possible to get an accurate cOlmt of the population by draining the water from the basin, collecting all of the fish, and separating,
measuring, counting and weighing each species present. While this destroys the
fish population it does allow an accurate count and weight of the fish present at the
moment they were collected.
In large impolmdments on a stream this technique is
impossible and unwarranted for many reasons.
5-1-1.
Methods of sampling fish populations.
In the search for techniques
that would provide reliable estimates of the fish population in a large impolmdment,
a number of methods for collecting fish samples have been employed. A listing of
some of the more commonly used methods are seining, netting (gill, trammel, and
hoop), trapping (baskets and boxes), trawling (a relatively new technique for freshwaters), fish toxicants (rotenone and antimycin), and electrofishing.
Coupled
with the use of these methods some investigators have collected, marked, released,
and then recaptured fish in an attempt to estimate the standing crop of fish in an area
by establishing ratios between marked and unmarked fish, captured by one of these
sampling methods.
63
5-1-1-a. Rotenone sampling.
The most popular technique employed
in recent years has been area sampling by use of rotenone.
This method employs
the use of a block net, which should have a mesh no larger than 3/8-inch, be of a
sufficient depth to reach from the surface to the lowest point on the bottom around
the perimeter of the sample area, and be of sufficient length to completely surround
or block an area of 2 or more acres.
This net is very carefully set arOlUld the
sample area several hours prior to the actual application of the rotenone.
It is
common practice to set a block net at night since there is less disturbance of fishes
within the area and possibly more fish are in the shallow water areas during darkness.
Care must be taken in setting the net to have the lead-line in contact with
the bottom at all points around the sample area.
It is also helpful to leave this net
in place for at least a day after rotenoning or until the bloated fish are all recovered
to prevent their floating all over the lake.
To determine the quantity of rotenone required to collect fish, the volume of
water within the block net is determined.
The quantity of rotenone to apply is at
least sufficient to give a concentration of 0.05 ppm rotenone for the entire volume
of water within the area. After the quantity of rotenone needed is measured it is
mixed with several volumes of water, and the mixture is pumped down a perforated
hose to produce a uniform concentration from surface to bottom throughout the
sample area.
The usual application pattern is to block all four sides with a wall of
rotenone and then make diagonal crosses from corner to corner.
Sufficient potassium permanganate (2 pounds of KMn04 for each pound of 5
percent rotenone compound used) should be on hand to start neutralizing the
64
rotenone in the waters outside the block net a few minutes after the fish begin to
surface in the sample area.
Care should be taken to apply the KMn04 far enough
from the net (at least 20 feet) to prevent undue chemical damage to the rope and
webbing.
For best results in recovering fish, sampling with rotenone should be done
when the water temperature within the area to be sampled is no lower than 75 degrees.
The higher the water temperature when rotenone is applied the faster fish will react,
also those fish which sink to the bottom when killed will bloat and float much quicker
allowing greater total recovery as well as more accurate weights and measurements.
It is also imperative that an adequate crew equipped with sufficient boats,
(at
least 10 per acre), nets, and containers be on hand when sampling starts, and that
the crew remains available for the second day pickup. All pickup crewmen should
be advised to pick up all fish seen, whatever species or size it might be.
In addition to collecting the fish from the sample area, there must be an adequate sorting, measuring, and weighing crew eqUipped with accurate measuring
boards on sorting tables, with sufficient containers for holding sorted fish, and
accurate scales for weighing the various inch-groups of each species. Accurate
identification of species and accurate records of numbers and weights of each inchgroup for each species must be stressed.
If this method is used to sample a fish population, and great care is taken to
collect all fish from within the sample area, and to record accurately all weights
and numbers of each inch-group of each species, then a reliable estimate of the
fish population within this type habitat in the reservoir may be obtained.
65
When selecting sites for rotenone sampling of fish populations it is important
that the specific areas chosen be representative of as large an area of comparable
habitat in the lake as possible.
Rotenone sampling can be effective in water depths
to 20 feet, but at greater depths the dispersion of toxicants is very difficult. AIso,
since block nets must reach from the sUl'face to the bottom of the sample area, use
of this teclmique is restricted to relatively shallow water.
Likewise, stumps and
snags must be minimal to allow setting of a -block net and also to allow free movement of fish collecting crews throughout the sample area.
5-1-1-b. Electrofishing.
Electrofishing devices are currently being
used in sampling techniques that count or collect game, forage, or rough species of
fish in shallow water areas of rivers and impoundments.
If such equipment is pro-
perly operated, and the biologists are careful in their capture and data taking techniques, this fish sampling method results in practically no mortality to the fish
population. This makes electrofishing advantageous over the rotenone method so
far as public relations are concerned.
The electrofishing gear consists of a
no
volt, 60 cycle AC generator with at
least 3,000 watt output, a control panel with variable AC or DC voltage outputs, a
heavy duty 2-pole foot-operated switch, and an electrode system that can be arranged
in various configurations to produce the desired electrical field.
The specific elec-
trode configtu'ation used to sample the fish populations in Corps lakes was a rectangle, 1. e. a terminal electrode was located on the outermost end of each of the
2 booms some 12 feet in front of the boat and another electrode was located on each
66
of these booms some 6 feet behind the outermost ones.
The width between the tips
of the booms was approximately 10 feet.
This electrofishing equipment was mOlmted on a wide beam, square bow, 16foot aluminum boat powered by a 25 h. p. outboard motor.
The bow section of tills
boat was covered with a square deck and fitted with a 3-foot illgh guard rail.
When
operating, the electrodes were adjusted to be suspended about 5 feet into the water.
With the power supply operating, the unit was adjusted to produce a load of approximately 800 watts witilln the electrical field.
The procedure used with this electrofishing operation was as follows.
The
biologist on the bow of the boat was equipped with a dip net while the boat operator
was equipped with a tape recorder.
As the fish surfaced in the electrical field
they were identified, counted, and this information was recorded on tape.
Selected
sizes of all species that were affected by the electrical current were collected by
net and their total length, depth, and weight were determined and recorded.
Scale
samples were collected for age-growth determinations, and condition of the ovaries
was examined in samples collected during spawning" season.
5-1-2.
Fish population studies (rotenone).
There were no pre-impoundment
rotenone samples collected from Okatibbee Lake area.
Fish population samples
(using rotenone) were taken at various sites on Okatibbee Lake in 1971 and 1972.
The identity of sample areas and results of these population studies are summarized
in Table 12.
From these studies it was determined that the fish population was
overcrowded by gizzard shad, and that a majority of these shad were too large to be
utilized by the resident predatory groups.
67
Table 12.
Fish population data collected by rotenone sampling in the Okatibbee Lake in 1971-1972.
Community Lall(lin"
22-23 Sep '71
North of rsl:md
2"-2!l Jul '71
00
Lhs
AT
·Hi
19.2.1
!.l2
17. G5
D5
15.51
U2
.52
50
IG.12
7·'
·I.I'H
D2
22.15
!i ~J
78
.8G
87
13 . .18
23
2.05
·12. ·16
5~J
I. 30
'00
.7:1
ti2
D.uG
"'
OS
25.17
GO
97.n!)
2!)
.57
58
2.G3
17
L:ll'gcmouth bass
10.88
88
:10,(;1
Wllite crappie
1.:1.1
'0
nl:ICk cr:lppic
I. 17
Chain pickerel
-
H('II-ca r
.13
sh
Warmouth
Gl~zard
:1:1. 20
:W
.20
0
2.1-1
55
I. 72
22
.05
0
.O!)
0
.35
(;:1
.11
"
. :18
13
.36
:1:1
5.95
'00
. 12
0
·12!L 01
12
0
100
G.74
.1-1
3.2·'
68
.0'
0
"Hi
0
.25
20
.I!J
88
2.82
22
5.82
70
H;'(::\
no
1.1:1
G3
1. 3G
7 ~l
.:l!)
0
1. ZO
'00
Z.:W
5'
. ilG
'00
20.70
!!l
.!il
"
9. !J()
'00
H.70
tOO
'00
10.:15
·lfJ
1:; 17
'00
z.no
'00
15
151. .j"
22
153.1,1
20
!i I. 85
·12
:\. 00
shad
12
.f)(j
Channcl ('atJish
Bowfin
27.'1-1
0
C':\l'p,.'.lCke r
SpottC'<! suckcrs
·'0
.0'
C:11'p
1\\I11hc:ld
(i!)
".1.
.27
~'J1l(jsh
Or:lllgcspottcd sunfish
(jl'CCll s\lllfi
11-1~Scpt72
AT
Lbs
Western spoiled
I'inc Springs I.anding
Lbs
AT
0>
7-H Sep '72
AT
I.bs
Longea" sunfish
Cartc'!' Hill Ll.lldin~
Lbs
Species
BluC'!till
--i\T
House Creek Bri<lg-e
22-2:J Aug '72
·12.22
Table 12, cont'd.
North 0f Islanu
28-29 Jul
Species
Lbs
i\lisccl):l11cotlS minnows
'71
kr
COlllmunlty L:lnding"
22-2:J Sell
Lb!S
.1:3
'71
AT
0
House Creck Bl'hlgc
22-2:1 A\11; '72
Lbs
A '1'
.40
0
.00
0
Carter IIill L;m{lin~
7-8 Sep '72
Lbs
.27
AT
0
Pine Springs Lalllling
11-12 Sep '72
Lbs
.J.!
t\lil;ec\l:mcous d:lners
Pi rale pCl'ell
'"'"
(in ,.
-
Fie
ric
AT
0
.02
l\latlt(llllS
Total
• Or.;
fl!l. 23
:129. Hi
307.76
liG. r.:1
;)51. 2:1
u7
7.12
.\. :i5
3.23
27. :::!f,
.06
.33
.33
.17
.n
2·1.87
5 I. 5~
23.11
26.51
-1.2·1
-I.
AT
0
These fish population data were summarized by methods proposed by SWingle
(1950) to describe the relationships of dynamics of balanced and unbalanced fish
populations. A brief summary describing the meaning of terms used in this methodology of data evaluation is given below.
Balanced populations are defined as "-those capable of producing satisfactory
annual crops of harvestable fish.
They were characterized by having (1) a definite
range in ratio of the weights of forage and piscivorous species,
(2) a narrow range
in ratios of weights of small forage fishes to the weight of piscivorous groups, and
(3) more than 33 percent of the total population weight in the form of fishes of
harvestable size. "
The "C" value is the weight in pounds of "C" class species and the "F" value
is the weight in pounds of the "F" class species.
The range in F/c ratios in
balanced fish populations was from 1. 4 to 10. O.
Populations with F Ic ratios from
1.4 to 2.0 were overcrowded with
"c" species. Balanced populations with F/c
ratios below 3 were inefficient due to the overcrowding of
"c" species. This con-
dition was found to reduce the total weight of the population.
The F Ic ratio was a relatively stable value, remaining almost constant despite
variations in rate of fishing for "F" and "C" species.
TIllS ratio is useful in com-
paring and determining the condition of fish populations.
The "Y" value in a population is the total weight in pOlmds of all fishes in the
"F" class which are small enough to be readily gulped by the average-sized adult
in the "C" class. The Y/C ratio is an expression of the food available to the "C"
class. The most desirable populations were in the range Y/C = 1. 0 to 3. O.
70
The "AT" value is the percentage of total weight of a population composed of
fish of a harvestable size.
In balanced ponds the range was from 33 to 90. The
most desirable populations had values between AT
~
60 to 85.
The "E" value of a species is the percentage of weight of a population composed
of that species.
The "F" class and also "F" species were subdivided into groups of "large".
1. e. fishes of harvestable size; "intermediate". 1. e. those too large to be eaten
by the "C" species and too small for harvest; and "small". 1. e. the fishes small
enough to be eaten by the average-sized individuals in the large group of "C" species
in the population.
The "A F" value is the percentage of the total weight of the" F" class composed
of large fish.
The "IF" and "SF" values are percentages of the total weight of the
"F" class composed respectively of the "intermediate" and "small" fishes.
An "A F"
~
35 appeared to be the minimum value fOLIDd in desirable populations
and apparently e:>qJressed the maximlUn allowable depletion of the adult" F" species
if satisfactory production is to be maintained.
in the range "A F"
~
60 to 80.
The most desirable populations were
Satisfactory populations occurred in the "SF" value
range 15 to 40.
The "A F'"
"IF". and "SF" values were found to be dynamic values shifting with
changes due to harvest. predation and natural mortality.
Pond studies indicated that the harvest of adult" F" species increased the pounds
of
"e" species per acre, and that failure to harvest the former group resulted in a
decrease in the pounds of "C" species in the population.
71
Separation of various species into the various classes specified in the population
analyses outlined above are given in Table 13.
5-1-3.
Fish population studies (electrofishing).
The data obtained by
electrofishing in Okatibbee Lake during 1974 are summarized as the total number of
each species seen and number sighted-per-minute (Tables 14 and 15), and as the
relative condition (Kn > of the species offish collected and measured (Figure 6).
5-1-4.
Comparisons of relative condition (Kn ).
It has been suggested that
average length-weight relationships of major species of freshwater fishes be prepared
for the large geographic regions, and that these averages be used as a basis for the
determination of the relative condition factor, Kn .
Such a set of average length-weight
relationships for many species of fish from rivers, lakes, and reservoirs in Alabama
are available
eN.
E. Swingle and E. W. Shell, 1971), and these averages were used to
determine the Kn values for all major species of fishes collected from Okatibbee Lake.
The data for 1974 are presented graphically in Figure 6.
In these data a Kn value of
less than 1.0 indicates poor condition, a value of 1. 0 indicates average condition, and
a value greater than 1. 0 indicates good condition. The Kn values for Okatibbee Lake
are limited, but are believed to be unbiased, representative (electrofishing) samples
of the species present in this reservoir.
It is noted that the Kn values for bass indicate that this species is in good con-
dition, but that the size range does not include larger fish.
According to the best
information avaIlable these larger fish are scarce or non-existent in this population
The I<n values for crappie indicate an overcrowded population that is
72
Table 13 . Lengths (in inches) used to classify fish of different species as young, intermediate, or
harvestable. and as forage, carnivorous or other. *
Species
J,
-'I
""
Young
fish
0-12"
Paddlefish
08"
Spotted gar
0-12"
Longnose gar
0- 8"
Shortnose gar
1- 5"
Gizzard shad
Mooneye
1- 6"
Goldfish
1- 6"
1- 8"
Carp
Carpsuckers
1- 8"
Northern hog sucker 1- 7"
Smallmouth buffalo 1- 8"
Bigmouth buffalo
1- 8"
1- 8"
Black buffalo
Shorthead redhorse 1- 7"
River redhorse
1- 7"
1- 7"
Golden redhorse
1- 5"
Blue catfish
1- 5"
Channel catfish
1- 5"
Flathead catfish
1- 6"
White bass
Intermediate
11sh
13-31"
9-19"
13-19"
9-19"
7-11"
7-10"
9-12"
9-12"
8-10"
9-12"
9-12"
9-12"
8-10"
8-10"
8-10"
6- 9"
6- 9"
6-11"
7- 8"
Harvestable
fish
> 32"
.? 20"
? 20"
? 20"
? 6"
~ 12"
~ 11"
~ 13"
:a 13"
? 11"
? 13"
? 13"
~ 13"
? 11"
? 11"
? 11"
? 10"
? 10"
? 12"
~
9 '1
Carnivorous
fish
Forage
fish
-
0-12"
-
~
12"
All Sizes
All Sizes
All Sizes
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0- 8"
0-10"
0-10"
0-10"
0- 6"
Other
fish
-
> 8"
> 8 11
0
-
-
> 8"
> 8"
-
-
> 8"
> 8"
-
> 8"
-
> 8"
> 8"
-
-
> 10"
> 10"
> 10"
> 6"
> 8"
> 8"
> 8"
Table 13.
Species
...,
Warmouth
Bluegill
Spotted bas s
Largemouth bass
White crappie
Black crappie
Sauger
Freshwater drum
Miscellaneous
Small Fish
Young
fish
111111-
3"
3"
4"
4"
3"
3"
1- 8"
1- 5"
All
Sizes
Intermediate
fish
4- 5"
4- 5"
5- 8"
5- 9"
4- 7"
4- 7"
9-11"
6- 8"
-
Cont'd .
Harvestable
fish
>
6"
?. 6
~
11
9"
~10"
~
~
8"
8"
~12"
~
9"
-
Forage
fish
00000000-
5"
5"
4"
4"
6"
6"
6"
6"
All
Sizes
Carnivorous
fish
Other
fish
> 5 11
>
5"
> 4"
>4 11
> 6"
> 6"
> 6"
-
"'
* From
"An Evaluation of Cove Sampling of Fish Populations in Douglas Reservoir. Tennessee"
in Reservoir Fishery Resources Symposium, 1967.
> 6"
Table 14. Total numbers of various groups of fish sighted in the electrofishing
field during four hours of shocking on Okatibbee Lake in May, 1974.
Total number
Group
Bass
45
Bluegill
150
Longear
8
Red-ear
1
Warmouth
1
White crappie
6
Yellow bullhead
9
Brown bullhead
11
Black bullhead
16
Pickerel
1
Gar
1
Gizzard shad
121
Total
370
75
Table 15..
Sights-per-minute of various groups of fish observed by electrofishing
in Okatibbee Lake in May, 1974.
Species
Sights-per-minllte
Bass
.19
Bluegill
.63
Longear
.03
Red-ear
.004
Warmollth
.004
White crappie
.025
Yellow bullhead
.037
Brown bullhead
.046
Black bullhead
.066
Pickerel
.004
Gar
.004
Gizzard shad
.500
Total
1. 540
76
Kn
White
1.5
1.4
Gizzard
Large1110ut hb
-
1.3
1.2 -
1.1
-
,
I,
!
1.0
""""
•9
-
·8
-
I
I
I
'II
I
I
II
•7
•6
.5
I
I
I
I
I
I
I
15
20
25
30
35
40
45
Figure 6.
I
I
I
10
15
20
Totallength (mm X 10)
I
I
I
15
20
25
I
15
Distribution of Kn factor for various sizes of four groups of fish collected from Okatibbee Lake in 1974.
20
25
30
lUlable to harvest forage species that are over 2 to 3 inches in length. The bluegill
1<n values are also in the poor range
indicating an overcrowded population.
The
problem with the bluegilis and other sunfishes is a lack of adequate fish-food organisms,
and this situation is aggravated by the annual winter drawdown.
The drawdown, on
the other hand, does concentrate the fish and makes those small enough for forage
more available to the piscivorous species.
5-J.
Fishing pressure.
The fishing pressure within Okatibbee Lake has been
rather intensive for the period of 1971 through 1973.
The estimated total nUluber of
fishermen trips in 1971 was 45,416 trips (they caught 93,070 pounds of fish).
It
was 31,416 trips (they caught 65,715 pounds of fish) in 1972, and no totals are
available for 1973.
The 1973 fishing pressure was believed to be somewhat lighter
due to a decrease in size of sunfishes and crappies. This decreased size resulted
from overcrowding of the fish population by sunfish, gizzard shad, crappie, and
bullhead catfish.
5-K.
Creel census.
A creel census is a method of bookkeeping designed to
determine the nun1bers and pounds of various species of fish harvested by various
methods, and the effort (time and manpower) required to obtain this harvest.
The
SlLrVey can be more sophisticated and determine the age and sex of fishermen, the
point of origin of the fishermen, and other facts if so desired.
Inherent in the
design of the census is the fact that daily and day-of-week fishing pressure, as well
as monthly fishing pressure and catch can be extracted from the data.
However,
the most important information is to obtain as accurate and complete record as
78
possible of the nwnbers and weights of each species of fish harvested from the
entire body of water, and the time required to attain this harvest.
An acceptable and usable creel census has been in operation on Okatibbee Lake
since 1971.
This creel has provided very important data on the yearly production
and should be continued to evaluate the trend in the fishery that will result from the
1973 shad control program, and threadfin shad stocking program which is currently
lUlderway,
Slilllmaries of the creel data are given in Tables 16 through 19,
79
Table 16. The estimated number of fishermen, hours fished, number of fish and the pounds of fish caught from
Okatibbee Lake in 1971-1972. *
March
April
May
June
July
August
7,699
13,953
8,024
2,852
1,714
1,615
Hours fished
23,120
49,772
32,191
11,550
8,242
7,105
,',Number caught
15,721
23,890
27,362
15,362
10,797
11,155
Pounds caught
15,490
18,416
19,315
7,046
7,418
3,975
September
October
November
December
January
February
2,914
2,270
1,005
2,191
561
921
45,719
10,238
11,408
6,143
3,286
4,101
3,730
170,885
Number caught
8,292
15,743
4,484
1,380
1,764
1,268
137,219
Pounds caught
4,914
8,787
4,116
732
2,051
821
93,070
Fishermen
00
0
Fishermen
Hours fished
* Mississippi
Game and Fish Commission, Fisheries Division.
Totals
Table 17. The .number and weight composition of species in ·total creel from
Okatibbee Lake for 1971-1972.
Percent in creel by
Species
\"eight
numbers
Largemouth bass
65.99
27.15
.20
.10
White crappie
5.11
10.10
Black crappie
4.96
11. 05
Bluegill
13.17
39.21
Red-ear
.41
.79
Warmouth
.60
1. 97
Channel catfish
.47
.36
Bullhead
5.48
8.16
Pickerel
.90
.43
2.70
.69
99.99
100.01
Spotted bass
Bowfin
Total
81
Table 18. The estimated number of fishermen, hours fished, number of fish and the pounds of fish caught from
Okatibbee Lake in 1972-1973. *
March
Fishermen
April
May
June
July
August
3,332
3,893
4,709
3,316
2,858
4,763
14,974
15,639
22,355
16,100
14,647
7,859
Number caught
12,129
13,293
24,367
13,846
4,834
2,515
Pounds caught
9,434
9,227
15,649
7,889
4,687
1,965
September
October
November
December
January
February
Totals
Fishermen
1,603
1,269
1,044
1,147
1,085
2,397
31,416
Hours fished
4,969
5,570
3,875
3,614
8,246
8,388
126,236
Number caught
4,820
2,785
6,123
3,108
4,123
6,123
98,067
Pounds caught
2,037
1,894
4,224
2,711
2,391
3,607
65,715
Hours fished
I
00
""
* Mississippi
Game and Fish Commission, Fisheries Di vision.
Table 19.
The number and weight composition of species in total creel from
Okatibbee La.ke for 1972-1973.
Percent in creel by
Species
weight
numbers
Largemouth bass
60.16
20.64
White crappie
13.09
26.69
Black crappie
7.98
18.11
Bluegill
5.86
20.52
Red-ear
.57
1. 74
Warmouth
.59
2.14
Channel catfish
.95
.45
Bullheads
7.07
8.86
Pickerel
1. 22
.40
others
2.51
.45
*
Total
*
100.0
Mostly bowfins
83
100.0
6.
MANAGEMENT OF THE FISHERY.
The management plan presented in this section is the one that has the most potential for iJXreasing fishing success in Okatibbee Lake for the cost involved.
It is em-
phasized that if post-operational evaluation of a particular part of the plan does not
provide the desired increase in fish production, this phase should be discontinued and
a different approach devised.
Also, in those cases where no economical management
plan can be devised, it will be recommended that the operational procedure remain at
its present status.
6-A.
Reservoir fishery biology.
This section is a brief review of some basic
biological processes of a reservoir fishery that were considered in evaluating the
fishery condition in Okatibbee Lake, and in the preparation of the Management Plan
that will follow.
The two principal problems involved in fish production are (1) the
production of an abundant supply of fish food, and (2) the management of the fishery
for a high sustained yield of harvestable sized fish.
An analysis of any reservoir fish population is a complex problem involving an
understanding of the habitat, the food supply, the biology of each species of fish, the
relationships that result from all of these species liVing together, and the impact of
removal upon a sustained harvestable population.
Information of the types of habitats, and the potentials for fish-food production
have already been discussed in previous sections of this plan. In summary, it can be
stated that a large portion of the Okatibbee Lake aquatic habitat is well suited for
macroinvertebrate (fish-food organisms) production.
However, the inflow of nut-
rients is inadequate, and water movement is too eA'tensive to permit the full
84
development of phytoplankton in this lake.
There was no evidence from any pre-
vious studies that other water quality parameters were inadequate to support moderate abundance of all forms of aquatic life.
Since Okatibbee Lake receives organic as well as inorganic waste products,
a diversity of food SOLU'ces is available which requires fishes of different feeding
habits to fully utilize these resources.
The species listed in Table 8
indicates
that an adequate diversity of feeder-types exists in this lake and its tailwaters.
The presence of such scavengers as gars, carp, catfishes, and bowfins indicates
the probability of a decreased rate of eutrophication in this lake.
Present eutro-
phic conditions are much less than would occur if these scavengers were not present.
Likewise, the presence of planktonivorous shads indicates utilization of
plankton and the production of a forage group to help support the population of
carnivorous basses, crappies, and catfishes.
6-A -1.
Factors affecting fish reproduction.
The continued existence of
all fish species in Lake Okatibbee depends upon their ability to spawu in this habitat.
There are many factors that affect the reproductive success of reservoir fishes.
Some of these factors are discussed below.
6-A -I-a. Adequacy of spawning area.
The type spawner, i. e. nest
builder or random, will determine whether or not adequate spawning areas exist
in the habitat (Table 20).
In the case of nest builders, spawning sites are located
on firm bottom materials consisting of gravel, clay, or silt.
85
Sandy bottom areas
,
:;';in.
S')ccie.
~Y"'-
Largemouth bass
n..-;I';; b... :ldBl'
'7(;1'
Si~(;,
:::J)_IWn.ng-
.,
'1'"
",in:ctnci
8-10
ne", .. b,;i IdeI'
:-';0.
~p.:\.'ll
::?... c y,--
.~.
Fry
:."IIin. L_tcb.cg:
SC:-.c,01in r .•
T\.;.
sinkin.;
.IC:: ....;"'i\·'"
9
",~r.c;';;:ll·
:::.mallmouth bass
,
<>;:-:..-:1 ..'""
70
1
70
J.G.. esl\'c
White 0.... 5S
r,est buiider
10
sink:ng
..dr."''''ln;!
Ea"torn piek",rei
"· ..I:..
o,n
15
sl;;•.i-!.;"Gy .....
S:-,u:;cr
1':1:1":0;11
L
D{.JJ";t>IVO
·13
sinlJ.r:b
Go
BLI..:k C,,',lp;nc
CO!O;ly 01' t>~i'.c:l..:
'I
nest builder
3:)-...:0
1
J,(,l.C.:i;VC
colony or ",i.nb'le
nest bui:der
7
colo;W
n..:;::;t b.lild.::r
3
colony
nl:t>~ LL.ildcr
3
Redl)l'east
colony
r.est bt<ilder
3
Round flier
nc:;t build;::!"
Warmouth
Groen ;:iunfisn
White cr;,pplC
58
00
51'''''''6'
aOli..:;",ve
2-2
SO
3
75
:;i.n;,:nb
ad;cs:vc:
2-3
'!l
3
heavy
a ....l.c.;,lvC
1
CG-63
nest builder
3
:ld:-:.csiH!
colony
n",st bu:!dcl'
3
.lohesivc
,
colony
builder
3
adhc;:,.vc
2
71-73
Channel e:ltfi&h
nc:,t b\lildel'
10.5
he;.v}'
:Hiilesivc
1
'/4
Speckled bullhe:l.d
nest builder
0
ndhcsivc
1
00
Golden shiner
random
5
.tc:,es:ve
3
Buf....lo
r,.ndorr'.
i3
Giaard shad
:·,.:JGom
5
ad;10:,;ve
,
Threadf,n shad
rar,dom
3
a(J:10::.:ve
3
llIucgill
Redeal'
Longear
sinkin~
;({.hc.;,ive
sin:-iilJ
ad~;c:;ivc
'0
6b-7u
n~::,t
sinid;:;
86
+
06
60
+
68
70
"?
are largely unsuited for spawning since these may be shifting bottom areas.
Nest
builders also have a preference of water depth in which to locate their nests. This
depth generally ranges from less than 1 foot to approximately 10 feet. Random
spawners require shallow water areas where an abundance of egg-attachment
materials (brush, grasses, and weeds) exist.
6-A-1-b. Water fluctuation.
Drawdown during spawning may destroy
a few or all nests and expose eggs of some shallow water random spawners.
Rising
water prior to spawning can dilute the repressive factor and induce basses, carp,
and buffalo to produce heavier spawns.
6-A-1-c. Water temperature.
The 6-inch water depth temperatures
at which various species spawn is shown in Table 20. The spawning success of
early spawners such as crappies and basses may be adversely affected by unusual
water temperature fluctuations.
6-A-1-d.
Silt laden waters. Water heavily laden with silt are un-
favorable for spawning of sunfishes and basses.
Sunfish in general are more toler-
ant to silt than are basses while bullhead catfish apparently suffer no ill effects
from silt. Random spawners, such as shads, carp, pickerels, and buffalo, whose
eggs may be attached to twigs, leaves of grasses, etc., are less susceptible to
silt damage than are the bottom spawners. An often overlooked but potential
siltation hazard, is produced by wind-driven currents that cause suspension of
shallow water silts and clays.
87
6-A-l-e. Repressive factor.
This is a self-inflicted type of birth
control first observed in g'oldfish, carp, and buffalo populations.
Basses and
sunfishes are thought to secrete a repressive factor which limits the extent of
their own reproduction.
6-A -l-f.
Size of brood fish. There is a size below which each species
of fish will not spawn. The minimum sizes of spawning fish of various species are
given in Table 20.
Slmfishes that are growing rapidly may spawn at a smaller size
than slower growing individuals.
6-A-l-g.
Food availability during period of egg formation.
Availa-
bility of food during periods of egg formation and maturation will influence the
number of yOlmg fish produced per female. Thus,heavy reproduction of a species
indicates rapid growth of brood fish; light reproduction, slow growth; and no reproduction, no growth or loss of weight by brood fish.
Some species such as sunfishes and shads can mature eggs within a few weeks
and spawn two or more times during a summer.
Other species such as basses,
pickerels, carp, catfishes, and buffalo require several months for egg formation.
Thus in these latter species reproduction success is influenced by conditions that
existed during the late fall, winter, and early spring.
6-A-l-h.
Crowding.
Since crowding results in less food per indivi-
dual, it results in smaller size brood fish and slower growth.
Crowding may re-
Slut from too many individuals of the same species ancl/or of competing species.
The results of overcrowding are reduced or no reproduction.
88
6-A-l-i. Egg-eating habit.
Under conditions of crowding, sunfishes
have been found to eat eggs of their own and other species.
When confined to sun-
fishes and competing species, this may be considered a beneficial type of birth
control.
However, when it is e>.1:ended and includes the eating of bass eggs, it is
extremely detrimental for it causes unbalanced populations.
6-A-l-j. Reproductive success of prey upon which predators feed
after reaching fingerling stage.
Since some predatory species require fish as
prey to produce normal gTowth, it is necessary that successful reproduction of
prey species occurs.
6-A-l-k.
Strength of predation upon young predator species. The
young predatory species are not exempt from the same predation that exists for
the young of other species. Among the basses, the greatest predation probably
occurs by those larger individuals of the school that start feeding on their own
brothers and sisters or on the young from a neighboring nest. This characteristic
of young bass to largely eliminate their nest mates makes the operation of bass
nursery ponds on reservoirs of dubious value.
6-A -2.
Predator-prey relationships. The rate and efficiency of predation
within a fish population depend upon a number of biological and physical factors.
Notable among the biological factors is the schooling habits of various species.
The largemouth bass fry, for example, are vulnerable to aU basses and crappie
of larger size.
Since they move about in a large school for several days after
89
leaving the nest they are easy prey.
Thus, a majority of fry of all basses may be
eaten by larger fish in a natm'al population before the schools break up.
Carp
eggs, fry, and fingerlings appear to be extremely vulnerable to bass predation.
This species cannot be classified as a true schooling species, but the fry and young
fingerlings seem to congregate into groups and this makes them easy prey for
predators.
Small shad also congregate into schools and predators are generally
lurking the environs of these shad schools.
The fry of most species of sunfish disperse more or less at random into shallow water areas upon leaving the nest.
A chief factor in the survival of large num-
bers of these species is the quantity of available cover in which these small fish
can hide from predators.
Filamentous algae and rooted aquatic weeds, if present
in sufficient quantities in shallow edges, provide excellent hiding places for many
small fishes.
Thus, weed control is an essential factor in establishing a healthy
predator-prey relationship in a reservoir.
The predatory species ("C" class) have been described as those piscivors which
consume any fish they can capture that is small enough to be swallowed at a gulp.
This suggests that a relationship exists between the size of the predator and its
prey. By research it was established that the mouth width measurement of the
predator species is equivalent to the maximum depth of body measurement of the
forage species that it can swallow.
Since mouth width and maximum depth of body
are related to total length of body, this relationship is generally expressed as the
total length of a forage species a bass of a given total length can swallow, and is
90
given in Table 21. This chart indicates that largemouth bass can start on a fish
diet at a very early age.
These relationships on mouth width of predators to depth of body of forage
species have been established for largemouth, smallmouth, and spotted basses,
and eastern pickerel as predators, and for bluegill, red-ear, goldfish, golden
shiner, and gizzard shad as forage species. It is believed that the same type relationship exists between mouth widths of crappies and catfishes and sizes of
forage fish they can gulp, but to date these have not been determined.
The presence of an adequate number of predators (piscivorous species) within
a fish population is essential if the forage species are to be thinned to the extent
that a sustained maximum harvestable crop of fish is to be produced.
The chief
predators for the reservoirs in this area include basses, the larger catfishes, the
pickerels, and to a limited extent the crappies. Unfortunately, our knowledge of
the activities of the larger catfishes is much more limited than it is for the other
three species.
Since the species dynamics of any reservoir fish population is
dependent upon the predator-prey (Fie ratio) relationship, a discussion presented
by Swingle and Swingle, (1967) concerning problems encountered with largemouth
bass and crappie predation is given below.
Largemouth bass are efficient predators upon small fish.
This species spawns
in shallow water in the spring and the young fry migrate into shallow water and feed
upon zooplankton, for which they must compete with all other small fishes in the
same environment.
From the size of I-inch on, they may feed upon mixtures of
zooplankton, insects, and small fish, depending upon their relative availability.
91
Table 21- Maximum sizes of forage fishes largemouth bass of a given inch-group can swallow.
Bass
Total length of forage fish
Total Length
lnchGroup
mm
<!>
''''
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
38
64
89
114
140
165
191
216
241
267
292
318
343
368
394
419
445
470
495
521
546
572
597
Bass
mm
24
34
44
54
68
82
96
120
132
145
158
169
183
196
229
249
263
278
292
298
342
355
369
Bluegill
mm
36
40
45
52
58
65
73
81
89
97
104
113
121
129
145
157
169
185
193
208
223
-
Redear
mm
Green
sunfish
mm
Golden
shiner
mm
26
32
37
46
54
62
72
81
91
100
108
119
129
139
159
173
188
202
-
36
41
46
54
61
69
78
87
94
104
113
122
131
141
159
172
186
199
212
229
-
45
52
60
72
82
93
106
119
132
145
156
170
183
197
224
243
262
281
301
-
-
Goldfish
mm
40
45
50
58
65
72
81
89
98
106
114
124
133
142
159
172
185
198
-
Gizzard
shad
Inm
39
45
52
62
72
81
93
104
115
126
136
149
160
172
195
212
230
246
263
284
305
327
Threadfin
shad
11un
28
36
43
56
69
79
91
102
117
130
140
155
170
Examination of rotenone samples indicated that growth of largemouth bass was
relatively slow during its first summer, and that there may be from 0 to more than
100 individuals per acre in various impoundments.
Since these small bass remain
largely in marginal waters it is the relative abundance of small fishes in these
areas that regulates their growth and affects survival.
Small gizzard shad are
seldom found abundantly in these areas making the bass principally dependent upon
fry and small fingerlings of minnows and the periodically spawning sunfishes during
their first growing season. By the time they are sufficiently large to migrate toward deeper waters, few gizzard shad-of-the-year are small enough to serve them
as food.
Those surviving over the winter are able to feed upon newly hatched shad
by follOWing schools over pelagic areas only at the expense of exposing themselves
to greater dangers of predation by larger predators. If the shad species is gizzard
shad, by mid-summer to late summer again few are small enough to serve as food
for the I-year bass.
In both ponds and large reservoirs, the presence of gizzard
shad as the principal forage fish results in two groups of bass: (1) the young O-toII-year groups which must grow slowly, with correspondingly high losses from
predation and other types of natural mortality; and (2) the rapidly-growing bass
which have become large enough to follow schools of shad over pelagic areas.
These latter bass have mouth wtdths large enough to allow them to feed year-round
upon larger shad.
Unfortunately, adequate studies have not been made in impoundments upon the
food-chains of small bass and factors affecting their growth and survival to larger
93
inch-groups. Until more is known of the importance of many of the supposedly
minor species to bass growth and survival, it is impossible to develop plans for
improving conditions and solving one of the problems in converting a reasonable
percentage of the shad crop into bass.
The two species of crappies appear to present similar problems in ponds and
large reservoirs.
Their principal characteristic is the cyclic nature of their
ablmdance. A strong year-class recurs periodically, at intervals of every 3 to
5 years. Age groups I and II of a strong year-class are typically crowded and
slow growing.
During this period, few young-of-the-year crappies survive, or
there may be no reproduction.
This is not because of the size of the crappie, as
even well-fed 2-ounce crappie are capable of spawning, but is due to crowding
within the species.
Crowding may prevent egg formation or the fry-eating habits
may prevent survival of a year-class. As the strong year-class passes to III or IV,
gradual reduction in numbers from fishing and natural mortality results in gradual
increase in size, and heavy reproduction again occurs.
Investigations in ponds have indicated that tendencies to periodic overcrowding
were due to the fact that crappie normally spawn earlier (68 0 F) than, or approximatelyat the same time as largemouth bass, which typically spawn at 70 0 F.
YOlmg crappie after hatching, spend a few days or weeks in shallow waters and
then migrate into deeper waters.
Early spawning by crappie and migration into
deep waters combine to make young-of-the-year bass poor predators uponO-age
crappie.
In bluegill-bass-crappie ponels, the numerous age class I bass are the
principle predators upon O-class crappies.
94
These basses are the galmtlet through
which the O-age crappies must successfully pass to establish a strong I age-class.
Consequently, it was found in ponds that despite heavy crappie reproduction, a
cyclic pattern of crappie abundance did not occur in populations in years where
strong I age-class bass occurred.
Strong I age-class of crappie developed the following year after there was
heavy reproduction by crappie dm'ing a year when few or no I age-class bass were
present.
Larger bass fed upon the larger fish and allowed survival of too many
small crappie.
Once the strong I age-class of crappie developed, numbers of
young-of-the-year bass declined, probably because of predation by crappie on
bass fry.
In state-owned public fishing lakes, once this cycle started, it was re-
peated within 4 to 5 years.
It was always evident from seining samples taken in
June when another cycle was starting.
This was evidenced by averages of 10 to
30 or more crappie finger lings per 15 -foot seine haul, with no age I bass by the
50-foot seine and few caught by the fishermen.
In balanced populations, it is of interest that low numbers of age I bass gener-
ally follow years with abnormally high mmiliers of age I bass.
Seining records on
e"1Jerimental ponds have demonstrated that in such years older bass reproduced,
but age I bass allowed very few or none to survive beyond the schooling stage.
Unfortunately, the rotenone samples taken in large impolmdments were useless
in studying this young bass-crappie problem.
Most rotenone samples were taken
from July to Septenilier and by this time practically all sizes of crappie had migrated to deeper waters.
If rotenone samples were taken also during the spawning
95
period of crappie, while most were in shallow water, a more useful census could
result. Possibly, periodic seining during spring to mid-summer would provide
a census of the O-class and its stU'viva!.
Trapping, creel census, and relative
condition data can yield information of frequency and length of cycles.
Crappies
are not lmdesirable species in either ponds or large reservoirs; biologists just
do not yet have techniques for their management.
As previously mentioned, the fish population in Okatibbee Lake was overcrowded
by large gizzard shad in 1973.
On 3 October 1973, the lake was treated with one-
tenth ppm (to 4-foot depth) of 5 percent emulsifiable rotenone to reduce the
ber of large gizzard shad.
mUl1-
The results of this treatment are given below.
Numbers and Weights of fish killed by rotenone
Species
Pounds
Gizzard shad
Largemouth bass
Bluegill
Crappie
Red-ear
Bowfin
376,613
343
447
180
19
210
Total
377,812
Percent weight
Percent number
98.22
.09
1.17
.47
.05
T
99.68
.09
.12
.05
T
.06
100.0
100.0
This amounted to a removal of 99 pounds of gizzard shad per acre so late in
the season that no further reproduction could occur in 1973.
It was hoped that this
selective poisoning had thinned the population of gizzard shad sufficiently to allow
a stocking of threadfin shad, made in April, 1974, to become established and provide a source of forage for the smaller crappie and bass.
96
Unfortunately, obser-
vations made in late May, 1974, indicated that a considerable number of large gizzard shad still existed in the population.
It was also noted that the sunfish and
crappie had not increased in size as had been anticipated.
All information gathered during the early summer of 1974 indicated that the
Okatibbee Lake fish population was overcrowded with sunfish, crappie, and bullheads.
It was also apparent that individuals within the population of largemouth
bass were too small to utilize the large shad as forage.
Thus, it appeared that
the lake was destined to remain overcrowded indefinitely unless an effort was made
to partially poison the lake and thin the numbers of bream, crappie and large shad.
It is noted that the nutrient levels in the waters of Okatibbee Lake are too low
to support anything more than a meager population of phytoplankton.
basic food source of all forage for game fishes is in short supply.
indicate the major limiting nutrient to be phosphorus.
Thus the
The analyses
Since this is a relatively
small impoundment that does not receive excessive floodwaters during warmer
months, it is within the realm of practicality to instigate a partial fertilization
program and increase fish production.
If the population was thinned and limited fertilization was practiced, the annual
winter drawdown would help maintain a balanced fish population and would aid in
marginal weed control.
97
6-B. R~sLUne of factors affecting fish production in reservoirs.
1.
The latitude and altitude of the drainage area and the reservoir determine the temperature of its water and the species of fish it may support.
2.
The shape, size, and geographic location of its drainage area determines
in large part the quantity of inflowing waters into a reservoir.
3.
The type of soil, and its management, on the drainage area determines
the sediment load borne by inflowing waters.
4.
The types of soils and agricultural practices employed on the watershed determine the natural nutrient concentrations in inflowing waters.
5.
The quantities of domestic and industrial effluent released into tributaries to the reservoir augment the flow of nutrients into the reservoir
enviromnent.
6.
The inflow - storage - output ratios of nutrients in a reservoir determine the trophic levels that are maintained.
7.
The storage of nutrients in bottom soils of reservoirs is dependent
upon water depth, flooding, and level of release of discbarge waters.
8.
The conversion of nutrients into phytoplankton will retard development
of macrophytes in shallow water areas of reservoirs, whereas the
conversion of nutrients into macrophytes will inhibit the development
of phytoplankton in a reservoll...
9.
The presence of macrophytes will act as precipitators of silt resulting
in more rapid clearing of water, but this process may result in elimination of shallow marginal areas in the reservoir.
98
10.
The maximum food production in a reservoir is attained when a moderate quantity of the available nutrients are converted into phytoplankton.
Excessive conversion of nutrients into phytoplankton will produce lmfavorable habitat conditions.
11.
The type of bottom in the euphotic zone of a reservoir may determine
in large meaSlLre the percentage of conversion of phytoplankton into
macroinvertebrates that serve as food for fish.
12.
The presence of other substrate materials, such as brush and rooted
aquatic plants, increases attachment sites for macroinvertebrate and
epiphyte production.
13. To efficiently utilize all forms of food available within a reservoir the
population of fish must include species whose feeding habits are adapted
to utilize these varied food sources.
14. The population of fish within the reservoir is composed of those species
present within the impounded portion of the stream at the time the dam
was closed. If other species are considered desirable or necessary in
the reservoir fish population they should have been stocked when the
dam was closed and allowed to expand with the native fish.
15.
There must be an adequacy of spawning areas in the reservoir to provide for almual recruitment to the fish population.
16.
A predator-prey relationship must be established and maintained that
is capable of reducing the total numbers of fishes to a level of maximum sustained harvestable-sized sport and commercial species.
99
17.
An excessive quantity of macrophytes can provide too much protection
for small fishes from predators and result in an overcrowded and
stunted fish population.
18.
There must be an adequate annual harvest by fishermen to remove a
high percentage of the harvestable-sized sport and commercial species.
Tltis will permit adequate reproduction and the mfL'<imum rate of growth
among the recruitments to the population.
19.
An abtmdance of large, trophy-sized bass or other species taxes the
available food supply and results in a decreased total standing crop
and fewer harvestable-sized fish.
20.
Inadequate removal of harvestable-sized fish results in an abundance
of older individuals that are more susceptible to parasite and disease
attacks.
21.
Parasite and disease infections are higher among" species with schooling"
habits. Also, incidences of infection are greater during spawning
periods when many individuals are crowded into smaller areas, and
antibody production is at its lowest level.
6-C.
Information vs. action. It is evident from the preceeding discussion
that all prior data gathered on Okatibbee Lake may be classified as Vital information
concerning the status of the fishery in this lake. It should also be mentioned that
this information has been used by the Mississippi Fisheries Division as the basis
for corrective management techniques that are aimed at improving fishing in
Okatibbee Lake.
100
6-C-1.
Public relations.
This phase of the Fishery Management Plan
might ':xl considered as the equivalent of customer's service in a large corporation.
Its purpose is to provide the fishermen with such information as the kinds and habits
of fish inhabiting Okatibbee Lake; the most successful methods to employ to catch
these fish; the (current) areas where fishing for various species has been most
successful; and weekly (dLU'ing hot weather) temperature and dissolved oxygen
conditions to indicate where fish might congregate.
The information on fishery biology is an integral part of the training of any
Fisheries Biologist.
The dissemination of this information to civic groups, con-
servation and wildlife groups, and school children could be most helpful to the
public to better lmderstand problems of fish production as well as in their harvest
of fish.
These presentations could be timely and include fishing techniques for
those species cLU'rently being harvested.
6-C-2.
Fishing access.
The points of access for boat fishing on Okatibbee
Lake are adequate to allow most areas to be within a 15 minute run from a concrete
ramp.
All ramps are adequate to handle normal boat traffic, but on certain days
there may be a slight delay due to very large crowds.
Banle fishermen (which comprise about 40 percent of total fishermen visits) have
had no special facility consideration.
They have simply had to be content with
existiIg ballie conditions regardless of their proximity to favorable fishing grounds.
It is suggested that this aspect of reservoir fishing could be improved in selected
areas by construction of fishing piers or dikes into favorable shallow water areas.
101
The piers could either be fixed (piling) or floating types.
The floating fishing pier
has an advantage that it can be moved if the conditions within the lake (such as a
drawdown) warrant new or different areas to access.
The dike, on the other hand,
cannot be moved, but in constructing the dike the material for the fill can come
from along each side, thus creating deepened water conditions that are more favorable to attracting fish and providing some added water depth to take care of drawdowns.
The topography of the Okatibbee Lake site lends itself very well to either
type of bank access.
6-C-3.
Fishing intensity.
It was stated in the Introduction that the pri-
mary purpose of this Fishery Management Plan was to prOVide the greatest sustained yield of harvestable-sized fish, based upon its basic fertility, within Okatibbee
Lake. To attain this yield requires a sustained fishing pressure, particularly
during those periods when fish are congregated, either on beds, or migrating upstream, in preparation for spawning.
However, to sustain the needed fishing
intensity requires that a majority of these fishermen catch fish.
6-C-4. Creel limits. It is contended that the present high creel limits
could be a factor that determines the relative fishing success of most fishermen.
It is well Imown that the consistent fisherman Imows where and when to fish, and
when he locates a bed or area where fish have congregated that he will remove one
or more limits on several consecutive days. This procedure does remove large
numbers of fish, and results in making it more difficult for the majority of less
102
expert fishermen to catch fish.
A lowering- of the total creel limit could tend to
spread the catch to include more fishermen.
This could result in a stimulus to a
wider fishing clientele which should be the philosophy for any public waters that
are created and managed from g'eneral public flmds.
The harvest of adequate numbers of commercial species, especially the catfishes
and carp, from Okatibbee Lake has been sporadic and in a sense restricted.
Unfor-
tunately, no data are available on harvest of commercial species to indicate how
adequately the present fish crop of all catchable groups is being- harvested.
Since
it requires approximately as much food to maintain a pound of fish as is required
to produce a pOlmd of fish, the harvest of commercial species should be encouraged
to release some of the pressure upon the food supply of the game species. By
proper selection of fishing gear, the probability of catching game fish by commercial
techniques is considerably lessened.
However, if our assumptions on game fish
harvest are reliable, then the removal of the limited number of game species by
commercial gear could only result in an improvement of the entire fish population.
6-C-5.
Evaluation of fisheries management changes.
The operation of
a concurrent creel census on game and commercial fishing would be the only way
to accurately evaluate any proposed changes in management practices in regard to
their influence upon total fish harvest in Okatibbee Lake. The continuance of the
creel census and population studies conducted by Mississippi Fisheries Division is
necessary to fully evaluate the impact that the gizzard shad control program and
stocking of threadfin shad will have upon the future fishery.
103
6-C-6.
Fishing tournaments and rodeos.
Another factor in adequately
harvesting the game fish population in a lake to sustain a maximum harvestable
crop, is the operation of bass tournaments and fishing rodeos. As mentioned previously, it requires about the same amount of fish food to maintain a pound of fish
as to produce a pound of fish.
For example, it requires about 4 pOlmds of fish to
produce one pOlmd of bass within one year.
It will require an additional 4 pounds
of fish to maintain this one pOlmd of bass through its second year of life, and if he
gains another pOlmd in weight he will consume an additional 4 pOlmds of fish.
Thus
by the time a fish is 2 years old and weighs 2 pounds he will have consumed 12
pOlmds of fish (enough food to have grown three one-pound bass in one year).
If a
bass lives to be 6 years old and weighs 6 pOlmds at the end of that period, he will
have consumed 80 plus pounds of fish during that period (enough to have produced
20 one-pound bass during these six years).
Fisheries management teclmology has not advanced to a stage to provide means
for producing these greater numbers of smaller basses in preference to the one
larger fish in larger impolmdments, and it is not known that if such a technique
were available if it would result in a balanced fish population in such impoundments.
These facts were pointed out to indicate that the removal of trophy sized basses by
tournaments and rodeos can have a beneficial effect upon a reservoir's overall fish
population in the release of pressure upon the available food supply.
in a brief stimulation of growth among basses and possibly crappies.
104
Tllis results
In any impoundment inhabited by g"izzard shad, it is necessary that the population
of basses consists of individuals of all sizes from young-of-the-year to old grandads.
As mentioned earlier, larger basses seemingly prefer near ma.ximum sized forage
fishes that they are capable of swallowing; thus these lunker sized basses are a
necessity to control the numbers of gizzard shad and other forage fishes.
Their
occasional removal only allows a slightly smaller bass a more abundant food supply
and an opportunity to reach the "lunker" sized category.
Tournaments and rodeos
have thus far only encouraged the gTowing-up of smaller basses. If tournament
activity is too extensive (in size and frequency) it could eventually result in a gradual decrease in sizes of larger basses, but it is doubtful that this point has been
approached in this lake.
Thus, from the fish manager's standpoint, a limited
number of moderate-sized tournaments and rodeos would be considered a desirable
means of harvesting a segment of the fish population that is taxing the available
food supply.
6-D.
Creel census evaluations. In conclusion, it cannot be over-emphasized
that the workability of any of the proposed practices or changes in management of
the fishery in Okatibbee Lake can only be evaluated by a creel census that is properly
designed and conducted in such a manner as to prOVide a reliable estimate of the
trend in total fish harvest.
The results of such a census must be constantly exa-
mined to follow the catch trends, and to check its sensitivity in evaluating the practices under study.
In those cases where it is indicated that a particular practice is
not increasing the total yield, this practice should be discontinued, or modified,
and if modified its effects should be closely evaluated.
105
7.
Coordination with Other Ag"encies
The establishment of a fishery habitat by the impoundment of Okatibbee Lake
created a problem of managing this public resource.
By custom, it has been assumed
that the fishes living in this body of water belong to the state until they are caught
and removed at which time they become the property of the fishermen.
States have
been resistant" to assume the management of these federally financed projects on
the grounds that no State revenues are derived from such installations whereas private utilities do pay taxes on their impoundment holdings.
this attitude will change in the immediate future.
There is no likelihood that
States do insist however, that the
fishery created by these federal impoundments is still their responsibility.
This
Plan assures the State of the continued role as principal participant in the manag"ement of fisheries within its jurisdiction.
7-A.
Personnel and funding. In light of the above situation, it must be assumed
that the Corps of Engineers has a responsibility to the public, who financed these
projects, to provide the financial means for their management. The procednres for
solving all management problems are details beyond the scope of this Plan.
However,
it is felt that the Plan can include some suggested methods for their initial enactment.
The Corps of Engineers should employ a skeleton staff of professional fisheries
management persolUlel to act as liaison between themselves and the State fisheries
biologists.
These Biologists should be provided witb adequate funding for each
reservoir under their jurisdiction to provide for collection of essential data and
conduction of public relation and other managerial aspects of each reservoir's fishery.
lOG
Okatibbee Lake could share a fisheries biologist with the Black WarriorTombigbee Lakes.
This biologist would coordinate the fisheries management acti-
vities between the Corps of Engineers and the fisheries biologists of Mississippi.
The various aspects of the program that are to be accomplished could then be contracted to the Fisheries Divisions of Mississippi's Game and Fish Commission, to
State Universities, or they could be conducted in-house.
Such an arrangement should
be designed to encourage State participation in the plan, and in-house implementation
would be used as a last resort.
The role of State Universities in this management
plan would be restricted to research activities in relation to specific biological or
management problems.
This fisheries biologist should be adequately trained in fisheries biology and
management, and have an M. S. degree.
The suggested rating would be a G. S. 9
or 11 in order to attract qualified persons.
The funding, provided by the Corps of
Engineers, for implementation and contimling the management plan of Okatibbee
Lake could be based upon fisherman usage estimates, and could be as high as $0.05
per fisherman visit.
This figure would provide adequate monies to conduct a good
creel census and to start some of the other activities set forth in this plan.
7 -B.
Cost-benefit projections.
It is impossible to place a value upon the bene-
fit derived by an individual for one fisherman visit to Okatibbee LaJ<e.
Certainly the
value would be several times the $0.05 cost per fisherman visit indicated above.
In
additim, for each fisherman visit, it is estimated that he placed into the local economy
(spent) well in excess of $1. 00 to make this visit. Thus, the cost-benefit ratio could
conceivably range from 1: 25 to more than 1: 1, 000.
107
7-C. Equipment for biologist.
The fishery management biologist must be
provided with certain specialized equipment if he is to be efficient and effective in
providing technical assistance that will result in a higher sustained yield of fish on
the stringer. The following items are basic to this biologist being self-sufficient
over the wide territory that he must keep under continuous surveillance.
1.
Pickup truck equipped with a lockable body cover.
2.
16' fiberglass boat (Boston Whaler type).
3.
65 or 85 h. p. outboard motor with a least an 18 gallon gas tanlc.
4.
Heavy duty boat trailer.
5.
Corps communication radios in both truck and boat.
6.
State communication radio in truck.
7.
Water sampling equipment to include:
a.
Dissolved oxygen-temperature meter with at least 50-foot lead or
probe.
8.
9.
b.
Water sampling bottle capable of collecting water sample at any depth.
c.
Ice chest and Cjuart size Nalgene plastic sample bottles.
d.
Secchi disc.
Fish sampling equlpment including:
a.
25' x 4' one-fourth inch mesh seine.
b.
Dip net with one-fourth mesh bag.
c.
Ice chest with plastic sample bags.
35 mm camera.
a.
Color film for slides.
b.
Black and white film for news releases.
108
7-D.
Job description - Fisheries Management Biologist. The qualifications
and duties listed below are minimum requirements for a Corps of Engineers Fisheries
Management Biologist.
Degree: M. S. in Fisheries Management.
Training to include:
1.
Warm-water fisheries biology.
2.
Management of large impoundment warm-water fisheries.
3.
Fish disease and parasites.
4.
Water quality in relation to fish production.
5. Aquatic plant identification and control.
6.
Fish identification.
7.
Statistics.
8.
Public speaking.
9. Journalism.
Duties:
1.
Thorough Imowledge of the fishery habitats within each Lake for
which he is responsible.
2. Knowledge of the surrounding drainage area, especially the sources
of domestic, industrial, and agricultural pollution.
3.
Knowledge of current sport fishing success on each lake including
most productive areas.
Inform public through news releases,
radio, T. V. and Lake bulletins.
4.
Knowledge of commercial fishing on each laJ,e including number of
fishermen, type of gear used, and kinds and amounts of fish harvested.
109
5.
Maintain surveillance for fish kills and determine cause(s). Report to
appropriate State agency.
6.
Current knowledge (at all times) of water quality conditions throughout each lake.
Share information with public through news releases,
radio, T. V., and posted information on lake.
7.
Maintain surveillance on aquatic plant (including phytoplankton) populations and determine when and where control measures should be
employed.
8. Cooperate with State fisheries biologists on all above-mentioned duties
so that both may better inform the public about the fishery within each
lake.
9.
Promote fishing interest through news releases, public appearances at
clubs and civic groups, and by personal contacts on lakes.
10. Identify, help develop, coordinate and participate (to be informed) in
any contractural management or research plan that may be in effect on
each lake.
11. Actively participate in local, state and regional fisheries organizations
to inform and be informed on current management practices.
12. Coordinate and encourage participation of each Resource Manager and
other Corps personnel on each lake project in collecting and disseminating information relative to that lake's fishery.
Note - This biologist could be most effective if he did not have citation authority. In
this way he can contact persons with valuable information, but who are noncommunicative with law enforcement personnel.
no
7-E. Budget.
The personnel required to implement this Fisheries Management
Plan consists of a District Fisheries Biologist and a Project Fisheries Biologist.
This Project Fisheries Biologist would be shared by Coffeeville Lake (20 percent),
Demopolis Lake (30 percent), Warrior Lake (20 percent), Holt Lake (20 percent),
and Okatibbee Lake (10 percent).
The work basis for Okatibbee Lake will be as
follows:
Project Fisheries Biologist,
GS-9, 10 percent, 26 days.
Estimated annual cost is as follows:
a.
Personnel
Fisheries Biologist (GS-9) ($13,791 + 32%) x .10
$
1,820
Contingencies (15 percent)
273
Supervision and Administration (15 percent)
273
b.
Equipment ($12,500 x .02)*
250
c.
Operating expenses
1,200
Subtotal
d.
3,816
Management Practices
Fishing piers, creel census, weed
control, population studies, etc.
5,000
Total Cost (32,000 x $0.275** per user day)
8,816
Total Benefits (32,000 x $1. 00 per user day)
32,000
*Equipment costs prorated over 5 year period.
**Due to limited use by fishermen the cost per fisherman
visit is greater than amount suggested in body of Plan.
III
8.
Research Needs for River and Illlpolmdlllent Management.
Improved techniques for evaluating the present and future fish populations in
rivers and impolllldments are urgently needed by state and Federal regulatory
agencies and by industries that are required to biologically monitor the effects of
their wastes.
Equally important, we need to utilize, at the optimum level, the
productive capacity of our natural surface waters.
Title:
Improvement and Evaluation of Fish Sampling Techniques for Use on Rivers
and Illlpolllldments.
Situation: One of the major problems confronting management of fisheries in rivers
and impolmdments is the inadequacy of available techniques to sample all facets
of the resident fish population. This is a distinct handicap to fisheries biologists
who are attempting to improve sport and commercial fish production.
Equally
important is the fact that it is virtually impossible for biologists to evaluate
either detrimental or beneficial effects of waste or heated-water effluents upon
fish production in rivers and impolmdments.
Objective:
1.
To devise a sampling system that provides total recovery of the standing
crop of fishes in a given area.
2.
To develop new sampling techniques that will permit the attainment of the
first objective.
112
3.
To evaluate the efficiency of individual sampling techniques to estimate a
portion or all of the standing crop under various types of habitats.
Title:
Factors Affecting Food Chain Development in Rivers and Impoundments.
Situation:
The availability of food is the chief factor involved in fish production in
rivers and impoundments.
Since the majority of fish foods are produced within
an aquatic environment, their degree of abtmdance is not nearly so obvious as
it is with terrestrial forms.
In addition, the characteristics of the aquatic
habitats are not so obvious as they generally are on land.
Most life history
studies of aquatic forms have been conducted singly ane! little effort has been
devoted to integrated food chain production studies.
Thus, the various factors
which may have the greatest influence upon the food chain for various species
of game and commercial fish are little Imown or understood.
Only through a
better tmderstanding of food chain relationships can fish production in many
waters be managed or improved.
ctJjective:
1.
To devise sampling techniques capable of collecting representative forms
of all major food groups for fresh water fishes.
2.
To more fully understand the general life-cycle of each group of organisms
that are components of the food chain for fish.
3.
To identify the physical and chemical factors that are beneficial and harmful to all component organisms in the food chain.
113
4.
Evaluate the gain or loss in efficiency of conversion for food chains of
varying complexity.
Title: Optimum Nutrient Loading for Maximum Fish Production in Rivers and
Impoundments.
Situation:
Plant nutrients, mainly N, P, and C, are generally the limiting factors
in the production of adequate food to attain the maximun1 natural production of
fish in rivers and impoundments.
Several other chemical and physical factors
seemingly influence the quantity of plant nutrient necessary for optimlm1 fish
production in a given aquatic habitat.
Experience in farm fish ponds has sbown
that the combination of factors are almost as variable as the munber of ponds
that have been studied, but there appeared to be average values for the components of the combinations that tend to optimize fish production.
It is believed
that similar sets of combinations exist to optimize fish production in rivers and
impolllldments.
Objective:
L
Correlate rate of nutrient flow with the standing crop of fish in rivers and
impolllldments.
2.
Compare fish production in impoundments resulting from agricultural and
non-agricultural nutrient sources.
Title:
OptimlUn Harvest Rate for Various Trophic Levels in Rivers and Impoundments.
114
Sitmtion:
It has been shown in pond research that individuals comprising a fish
population do not grow lUlless a sufficient number of the larger individuals
are harvested and the pressure on the food supply relieved to allow smaller
individuals to attain harvestable size. This rate of harvest was found to be
proportional to the available food supply. In rivers and impoundments the
rates of harvest of sport and commerical species are generally unknown.
The
same can be stated concerning the trophic levels of these same enviromnents.
The urgent need is to acclUllulate sufficient information to correlate optimum
harvest rates with nutrient input of the various streams and impoundments
throughout the Southeast.
OJjective:
L
To determine the optimum rate of harvest of fish from rivers and impolmdments with different rates of nutrient flow.
115
Synopsis
Okatibbee Lake, with a surface area of 3, 800 acres, a length of 4. 5 miles on
Okatibbee Creek, an average depth of 11. 1 feet, and a drainage area of 154 square
miles, is an upland flood control structure which at normal pool elevation of 343
feet msl covers the large, flat flood plain of Okatibbee Creek and its tributaries.
The lake is subject to excessive flood waters one or more times each winter and
spring.
These flood waters are temporarily stored in Okatibbee Lake and slowly
metered downstream to reduce flooding of Meridian and other downstream towns.
The degree of tLU'bidity associated with these flood waters is dependent upon the
severity of the flood-producing storms, but is less than might be anticipated since
the watershed has a fairly permanent vegetative cover.
The inflowing waters into Okatibbee Lake are relatively lUlpolluted since there
are only homestead and general farm waste sources on the watershed.
Thus, the
water quality, so far as dissolved oxygen is concerned, is relatively natural for
mixed farmland-timberland runoff.
directly related to rainfall.
Flows on Okatibbee Creek are variable and
The lake is subject to a decreasing water level in
late summer and fall due to low rainfall-runoff conditions.
Since there are no major sources of domestic, industrial, or livestock wastes
released into Okatibbee Creek or its tributaries above Okatibbee Dam, the supply
of plant nutrients, namely nitrogen and phosphorus, to the lake waters is very
limited. This results in a limited production of phytoplankton and other fish-food
organisms.
This fish-food supply is fLU'ther restricted during the fall and winter as
a result of the 4-foot flood-storage drawdown.
116
The flood-storag"e drawdown, on the other hand, is very beneficial as a
method for the control of marginal aquatic plants.
To date, there is no indication
that aquatic plants are going to be troublesome in this lake. The low nutrient
level in the waters and soils has also been beneficial in restricting the growth of
rooted aquatic plants.
It is suggested that a public relations program to alert the
public against the infestation of the lake with weed carried on boats, motors, and
trailers be instigated immediately to eliminate one major source of contamination.
In the spring of 1969, following the flooding of Okatibbee Lake the previous
winter, the lake was stocked with the following:
504,000
40,000
140,000
1,289
bluegills
red-ear
largemouth bass
striped bass
Thus, the natural fish population plus the stocked fish had an opportunity to expand
together.
Striped bass were stocked each year from 1969 through 1973.
Yearly
sampling, since 1969, of the fish population by use of rotenone indicated that the
gizzard shad had overcrowded the lake with individuals too large to be consumed by
the vast majority of piscivorous species present.
This sampling also indicated a
stLmted (overcrowded) bream and crappie population.
Creel census conducted
tlu'oughout this period indicated poor sizes of slmfish and crappie as well as a
yearly decrease in numbers of fishermen and total catch.
In OCtober, 1973, a shad thinning program using a 0.1 ppm (concentration in
total volLmle) emulsifiable rotenone treatment was initiated. This first thinning
eliminated an estimated 99 pounds of gizzard shad per acre.
117
In the spring of 1974,
a total of 7, 800 threadfin shad brood fish was stocked into the lake in an attempt
to estab lish this fish as another forage species. It is to be noted that the shad
thinning treatment resulted in a kill consisting of 99 percent shad and only one percent other species.
An examination of the fish population in May, 1974, indicated that the shad
thinning had been partially effective in reducing the numbers of gizzard shad, and
practically ineffective in reducing the numbers of sunfish and crappie. It was
also irrlicated that a stunted population of bullhead catfish existed in this lake.
Reports indicated that bass fishing was fair, but the individuals that were caught
were only moderate (2 to 3 pounds) sized. It was noted at this time that no school
of young shad were sighted on the lake. Either or both of the following factors
might have accounted for this absence of shad:
1. There was insufficient food to produce large spawns of shad.
2. The piscivorous fishes were consuming these small fishes as fast as they hatched.
In swnmary it can be stated that the 1973 shad-thinning practice was only partially successful in correcting the overcrowded condition within Okatibbee Lake.
ft is suggested that the Fisheries Division of the State of Mississippi continue
to conduct creel census and rotenone sampling programs to study fish population
composition and growth. It is further suggested that a marginal rotenone treatment(s) also be used to thin not only shad but also sunfish and crappie. A public
relations campaign prior to the actual operation could obtain public support for
such a practice.
118
Since Okatibbee Lake might be considered an over-grown fish pond that receives excessive flood waters for limited periods, and then remains fairly stable
from May through September, it is adapted to the use of a partial (500 to 600
pOlmds per acre) fertilization program. Analyses of the waters indicates that
there is a serious lack of phosphorus in the lake waters.
Okatibbee Lake has the potential of developing into a productive sport fishing
lake, but to achieve this status will require the use of all of the managerial
techniques available.
The Fisheries Division of the state of Mississippi is urged
to continue its management program on this lake, and the Corps of Engineers will
lend assistance through funds and personnel to help the state develop this facility.
119
References Cited
Swingle, H. S.
1950. Relationships and dynamics of balanced and unbalanced fish
populations. Auburn Dniv. Agr.
Swingle, H. S.
Exp.
Sta. Bull.
274. 74 pp.
1953. Fish populations in Alabama rivers and impoundments.
Trans. Am.
Fish.
Soc.
83 :47 -57.
SWingle, H. S., and W. E. Swingle. 1968. Problems in dynamics of fish populations
in reservoirs.
Reservoir Fish. Resources Sym. pp. 229-243, 1968.
Swingle, W. E., and E. W. Shell. 1971, Tables for computing relative conditions
of some common freshwater fishes.
183.
55 pp.
Auburn Dniv. Agr.
Exp.
Sta.
Circular
The development of this Fish Management Plan
was coordinated with the Plan currently in use on
Okatibbee Lake by the Mississippi Game and Fish
Commission. All aspects of this Plan were discussed
and agreed upon by the Mississippi Fisheries Biologists
prior to their incorporation into this document.