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15343

THESIS

This is to certifg that the
thesis entitled ’
Ln.Lnalyais Of The Bottom Fauna Production In

fertilized An'Unfertilized Ponds And It's
Utilization By YOungbof-the-Year Fish.

presented by

Mercer H. Patriarche

has been accepted towards fulfillment
of the requirements for

M-__degree in_ZQ_O_1_Q &_

M.W

Major professor

DateJril 1)" a 19kg

 

 

 

 

AN ANALYSIS OF THE BOTTOM mum
PRODUCTION IN FERTILIZED AND UNFERTILIZED
PONDS AND ITS UTILIZATION BY YOUNG-OF-THE-YEAR-FISH

By
.Mercer Harding ggtriarche

A THESIS
Submitted to the School of Graduate Studios of Michigan
State College of Agriculture and Applied Science
in partial fulfillment or the requirements
for the degree of

.MASTER OF SCIENCE

Department of Zoology

1948

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4"

ACKNOWLEDGMENT

I would like to express my appreciation to
Dr. RObert 0. Ball of Michigan State College to
whom I am especially indebted for his valuable
advice, close supervision and helpful criticism
throughout this investigation. I would also
like to extend thanks to the Institute for Fish-
eries Research and its Director, Dr. Albert S.
Hazzard, for making this work poséible. Grati-
tude is due to Mr. Ralph Marks, Regional Fish-
eries Supervisor; hr. Henry Hatt, District Fish-
eries Supervisor; and the personnel at the Wolf
Lake State Fish Hatchery for their aid and as-
sistance in carrying out the field work of this

problem.

203301 f

THESlS

IABLE OF CONTENTS

RAGE
INTRQDUCTIOROOOOOOOOO00.000.00.000.0.00.0000... 1

DESCRIPTION OF THE rouns....................... 3
METHODS AND EQUIEMENT "
StOoking.................................... 7
Fertilization............................... 8
Bottom Sampling............................. 9
Fish Collection............................. 10
Laboratory Procedure........................ 10
BOTTOM:EAUNA................................... 15
sTATISTIcAL.ANAtYSIs........................... 16
STOMLOHXANALYSIS............................... 18
DISCUSSION..................................... 21

SUMMARYC.00.......0OOOOOOOOOOOOOOOCOOOOOOOOO... 25

LITERATURE CITEDOOOOOOOOOOOOOOIOOOOOOOOOOOOOOOO 27

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INTRODUCTION

The Michigan Department of Conservation, in OOOpera-
tion with Michigan State College, made possible a series
of experiments to determine the probable effects of fer-
tilizer as applied to Michigan ponds and lakes, formulate
management policies for ponds, and obtain figures on cost
of application of the fertilizer. The experiment with
which this report is concerned was a measure of the effect
of fertilization on the fish-food organisms in pond waters
and a consideration of the utilization of these organisms
by the young-of-the-year fish.

Dredge sampling of bottom-dwelling fish-food organ-
isms was carried out on four experimental ponds at the
wolf Lake State Fish Hatchery as a means of determining
and comparing the productivity in terms of benthic fauna
in fertilized and unfertilized ponds. Physical, chemical,
and biolOgical data We‘collected on the pmds, two of
which were fertilized and two left unfertilized. Stomach
analyses were made of young-of-the-year bluegills to de-
termine qualitatively and quantitatively how the available
food in the ponds was being utilized by the fish.

The construction and management of farm fish ponds to
conserve water resources and provide recreation has com-
landed the attention of workers in other states for sever-
al years. Missouri and Texas have develOped an extensive

farm pond program. Alabama, Louisiana, North Dakota,

Oklahoma, and many other states have been active in similar
projects. muchigan, with some 11,000 lakes within the
state, has not had as great water conservation prOblems ncr
the need of establishing fishing waters as have some other
states. In recent years pOpular interest in farm fish ponds
as a means of better utilizing unproductive land as well as
providing recreation for the owner has develOped.

The practice of applying fertilizer to fish ponds to
attain a greater production of fish has been tried and used
successfully in India, China,IJapan, and.several Eurcpean
countries where pond fish culture has been carried on for
centuries. Since 1930 several investigators in America
have carried out wmrk on fertilization and pond management
with varying degrees of success (Davis and Wiebe, 1930;
HOgan, 1-953; Meehean, 1933; M. w. Smith, 1954; Swingle and
Smith, 1939, 1941, 1942; Tack andeorofsky, 1946; Swingle,
1947).

‘The role that fertilizer plays in the production of
fish is an indirect one in that it supplies the nutrients
for the growth of phytOplankton, the primary food material
upon which all fish are directly or indirectly dependent.
Golden shiners, giszard shad, and goldfish use phyto-
plankton directly in addition to other foods. Bluegills,
small crappies, and young bass depend on the phytOplankton
indirectly in that they feed on zooplankters and on insects
which, in turn, rely on the phytOplankton, the bacteria
that decompose it, and their own kind for food. Inasmuch

as the larger carnivores prey on small fish they, too, are
indirectly dependent on this fundamental phytoplankton.

In order to measure the productivity of a body of
water, several workers have attempted to determine the re-
lationship of average weight of bottom organisms per square
foot and pounds of fish per mile of stream or acre of water
(Richardson, 1921; Surber, 1937; Davis, 1938; Tarzwell,
1938; Howell, 1941; and Ball, 1948).

However no single index of productivity has been adOpted
for, as Helch (1935) pointed out, two considerations are in-
volved in devising a single index of general biological
productivity (1) the inherent capacity of a lake to support
life (biotic potential) and (a) the actual productivity at
a given time. Several indices including bottom fauna have
been proposed but all have weaknesses. When a rich benthic
fauna is present high productivity is common but not neces-
sarily insured. It is believed, however, that the standing
crop of bottom.organisms will give a comparable measure of
the productivity ofponds such as were under consideration

in this investigation of pond fertilization.
DESCRIPTION OF THE PONDS

The field work was carried out during the summer of 1947
at the Wolf Lake State Fish Hatchery, the largest hatchery in
the state, located ten miles west of Kalamazoo in Van Buren
county, unchigan. Two pairs of ponds, selected on the
basis of similarity in size, bottom type, and source of

“d

water supply, were assigned to this problem. These were
Ponds 7, 12, 20 and 21 and their location is shown on a map
of the hatchery (Chart 1).

Ponds 20 and 21 were paired, Pond 20 receiving the
fertilizer treatments and Pond 21 being untreated. In like
manner Ponds 7 and 12 were paired, Pond 12 being fertilized.

Pond 20 has a surface area of 2.3 acres, Pond 21 an
area of 2.2 acres, and both ponds have a maximum depth of
about 6.5 feet. Their bottom soil types are similar, vary-
ing from a mixture of sand and marl in the shallow areas to
a black muck in the deepest part of the ponds. Water is
supplied directly to Pond 20 from the Number 3 Spring, one
of three springs which, in addition to water pumped from
Wolf Lake, supply the hatchery. Pond 21 is filled from the
overflow of Pond 20.

Mbnthly chemica1.ana1yses of the water did not indi-
cate any great difference between ponds in the total hard-
ness of the water, the average for Pond 20 being 114 p.p.m.
while that of Pond 21 was 95 p.p.m.. No free carbon dioxb
ide was indicated for either pond.

There was an.abundant growth of submerged higher
aquatic plants but only four genera were represented in the
flora. The dominant plant in Pond 20 was the water weed
Lnacharis sp. which flourished throughout the pond. ghggg.
sp. was second in.abundance but was confined to the shallow
water. Two species of Potamogeton were also present - g.

crispus and P. Hillii. Mats of filamentous algae covered

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approximately one-fourth of the surface area of the fertil-
ized pond throughout most of the summer, capacially above
the thick submerged weed bed in the shallow end of the pond.
Pond 21 also had a profuse growth of m sp. but the domi-
nant plant in the pond was m sp. tOgether with a scat-
tering of Anacharis sp. and Potamogeton Hillii.

 

Ponds 'l and 12 are almost an acre smaller than the
aforementioned ponds, having 1.5 and 1.6 acres respectively
and a maximum depth of about seven feet. The bottom type of
both ponds is a black organic muck, Pond 12 having, in addi-
tion, considerable organic detritus. The water supply for
Pond 12 comes from the adjacent Pond 6 which receives water”
from both Wolf Lake and the Number 1 spring. Pond '7 is
supplied indirectly from the same spring via the overflows
of Ponds 4 and 5.

Chemical analyses of the water indicated an average
total hardness of 117 p.p.m. for Pond 12 and 137 p.p.m. for
Pond 1, no indication of free carbon dioxide for Pond 7 but
one test at the end of August in Pond 12 showed 8 p.p.m. of
free carbon dioxide in the water, presumably due to the de-
cay of the filamentous algae.

These experimental ponds likewise supported luxuriant
plant-growths. The dominant plant in Pond 12 was 39.125. sp.
with _C_h_a_r_a_ sp. in the shoal areas tOgether with Potamogetcn
Hillii. After fertilization was started an abundant growth
of filamentous algae appeared in this pond and remained un-
til the end of August. Pond 'I supported a floral popula-
tion which included Ceratcphzllum demersum, Anacharis sp.,

 

Potamogeton Hillii, and an excessive growth of 33122 and
Tara.

The presence of higher aquatic plants in any large
quantity in small ponds is undesirable for several reasons.
In the first place they may seriously deplete the dissolved
oxygen content of the pond water at night or over a period
of several cloudy days thereby causing suffocation of the
' fish. This is especially true in fertilized ponds where a
phytOplankton bloom may have develOped which will further
tax.the oxygen supply. Secondly, a luxuriant growth will
provide too many places for the young fish to hide thereby
reducing the chances of the bass, or any other predator, of
controlling their excess numbers. Consequently the pond be-
comes overcrowded and stunting results. And, finally, the
plants have a nuisance value in.that they interfere with
harvesting of the fish.

Swingle and Smith (1941, 1942) have employed fertilizer
successfully to control submerged aquatic plants. The fer-
tilizer induces a plankton bloom which shades the plants
thus reducing their photosynthetic activity and as a result
the plants die. Observations on thefertilized Pond 12 at
Wolf Lake showed that at the end of the summer the submerged
plants had almost completely disappeared and in Pond 20
there was little evidence of the pond weeds (Potamogeton)

 

but Anacharis seemed unaffected. There was no apparent re-
duction in the higher aquatic flora in the unfertilized
ponds noruagg'there any extensive filamentous algal mats in

these ponds. Apparently the mate of filamentous algae in

the fertilized ponds were instrumental in eliminating the

pond weeds with the exception of the Anacharis and Chara.

 

IA Secchi disk was used to measure the turbidity of the
pond waters every week but the water remained clear until
the last week in August when readings of 58 inches were ob-
tained in the fertilized Pond 20 and 50 inches in Pond ll,
the other fertilized pond. These plankton blooms were ob-
served after the filamentous algae disappeared. Slight
blooms were recorded in all ponds for July 7 and August 12
but they were not heavy enough for a turbidity reading.

It is more desirable to develOp a heavy plankton bloOm
than filamentous algae since excessive growths of tgié£1at-
ter formscf algae are generally considered obnoxious inas-
much as it interferes with fishing and other harvesting Op-
erations. Swingle (1947) concluded that filamentous algae
could be prevented by applying inorganic fertilizer only
after the water has warmed up in the spring. At this time
the plant nutrients are dispersed throughout the pond from
top to bottom rather than settling immediately and are
available to the plankton algae instead of the filamentous
forms.

METHODS AND EQUIPMENT
Stocking

The ponds were stocked with a combination of adult
bluegills (Lepomis macrochirus) and yearling largemouth
bass (Micropterus galmoides) at the rate of 12 bluegills

and 150 base per acre for Ponds 20 and 21, and 40 bluegills
to 150 bass per acre in Ponds 7 and 12. The bluegills that
were used in stocking the ponds were in poor condition. To
offset an anticipated mortality extra bluegills were put in
the ponds, the increase being in prOportion to the stocking
rate Just described.
The following table (Table 1) shows the numbers and

planting dates for the four ponds:

 

 

 

 

 

 

 

 

 

Table 1

POND SPECIES NUMBER PLANTING DATE
7 Bluegill 76 5/20/47
Largemouth base 240 4/15/47
12 Bluegill 86 5/20/47
Largemouth base 240 4/15/47
20 ' Bluegill 41 5/20/47
Largemouth base 345 4/15/47
21 ’ Bluegill 59 5/20/47
Largemouth bass 550 5/1 /47

Fertilization

.A 10-6-4 commercial inorganic fertilizer containing 10
per cent Nitrogen, 6 per cent available Phosphoric Acid, and
4 per cent Potash was applied to Ponds 12 and 20 at the rate
of 100 pounds to the acre every three weeks between April 2
and August 6.

At the outset two methods of fertilization were tried.

One method was to broadcast it from along the shore and the
other was to spread the fertilizer over the pond surface
from the back of a boat as it was rowed around his pond. The
latter method proved to be the most effective and was used
throughout this work.

Bottom Sampling

A total of 255 bottom samples were collected by random
sampling from the four ponds between the last week in June
and the middle of September. Seven samples were collected
eadh week in Ponds 20 and 21 and 6 per week in Ponds 7 and
12. As time did not permit adequate sampling of the entire
pond a section Judged typical of the pond was selected and
the dredge samples were collected in this area, every effort
being made to insure randomness in the sampling.

A Peterson dredge, which covers an area of .826 square
feet, was used for the sampling. After a bottom couple was
obtained, the dredged material was put into a tub and any
plant naterial brought up was removed, washed in a 30-mesh
sieve, and placed in a quart Jar containing a little water.
The remaining naterial was thoroughly stirred in water in
the tub and poured through the sieve. The organisms and res-
idue remaining were washed several times, put in another
quart Jar, and all samfles taken to the laboratory. If they
could not be picked over within a short time the samples
were kept in a refrigerator until such time that they could

be sorted out and preserved in 80 per cent alcohol.

10

Fish Collections

Bluegill fry were first Observed in the pends on July 8.
Beginning the first week in August, at least 25 were collect-
ed weekly from each pond by seining and taken to the labora-
tory where they were measured and the stomachs removed and
preserved in 10 per cent formalin for future analysis. A
total of 503 fish were collected and their stomachs preserved.

Seining was done from a boat. One end of a fifty-foot,
fine-mesh seine was weighted and, after selecting an area
over a weed bed, the weighted brail was tossed into the water
from the rear end of the boat and the not passed into the
water while an assistant piescribed a small circle with the
boat and returned to the starting point. The seine was then
hauled into the boat and 25 or 30 fingerlings were trans-
ferred to a pail and taken to the laboratory. In the fertil-
ized ponds, one cast was all that was required to collect the
desired number of fish whereas in the control ponds often

several tries were needed.

Laboratory Procedure

Bottom samples - The method employed in separating the
organisms from the bottom sample debris was to place a por-
tion of the sample in a white pan, add a little water, and
remove them as they were detected moving around. However,
the plant samples required a different technique. A "salt-
ing out" process was used to facilitate separating the

ll

clinging organisms from the plants and, by doing this, great-
er assurance was felt that all of the minute invertebrates
(as well as the larger ones) were obtained.

This method cOnsisted of preparing a saturated salt solu-
tion.in a pan, immersing a few of the plants, and stirring
them around in the solution. After letting it stand a few
minutes, the organisms were removed as they floated on the
surface and preserved in 80 per cent alcohol with the others.

The quantitative analysis can be made by either comparing
the dry weights or the volumes of the organisms with numeri-
cal counts. Because many invertebrate organisms in bodies of
water differ considerably in size, it has been found desir-
able by many investigators of bottom fauna production to con-
sider their data both volumetrically and numerically (Tester,
1932; Lyman, 1942; Ball, 1948). unless both methods of eval-
uation are considered, a false concept of the invertebrate
population may be obtained. .As, for example, in the samples
from Pond 12 it was found that leeches made up only 3 per
cent of the bottom fauna population numerically but more than
53 per cent volumetrically.

The volumetric method was employed,along with numerical
counts, in this analysis because it is relatively faster
than the dry weight method, requires simple equipment, and is
sufficiently accurate for this work. As determined by Ball
(1948), the conversion factOr fer changing the preserved
volume of organisms in cubic centimeters to an equivalent

live weight in grams is 0.98. Fur purpose of this problem

12

one cubic centimeter of preserved volume is considered as
one gram live weight.

In making volumetric determinations, the organisms
were first placed in a graduated centrifuge tube and the
alcohol allowed to drain off the sample by putting the tube
in a rack which was inclined at about a 45 degree angle.

To measure the volume of the invertebrates more alcohol was
then added to the tube from a burette until the entire sam-
ple was displaced in the liquid. By using a burette which
had been calibrated with the centrifuge tube, the differ-
ence in readings between the two scales was noted and re-
corded as the total volume of the sample. The inverte-
brates were then sorted into taxonomic groups, counted, and
their group volumes measured.

£222 analysis - The stomach analyses were made under a
binocular microscope. Numerical tabulations were made of
the contents and the food organisms identified. (Observa-
tions were recorded on the presence of any other material
in the stomachs. Volumetric determinations were not made
because the limitations of the equipment would not permit
an accurate measurement of’the minute organisms. This
omission is not considered serious because, in a food study
of fish of this size (1.3-2.6 inches), numerical data will
provide a significant index to the food habits of the small
fish.

13

BOTTOM FAUNA

Charts II, III, IV, and V show the composition of the
,_bettom fauna pOpulations of the dredge samples taken from
the four ponds, both numerically and volumetrically. From
these it can be seen that the midges were, numerically,
the dominant organism in three of the four ponds. The
Chironomidae were the most abundant, followed by the
Ceratcpogonidae and the Chaoborinae. The latter appeared
in the bottom samples from Ponds 12 and 21 about the mid-
dle of August and became abundant in Pond 21 in September
but none were taken from the fertilized Pond 20 and only
one from Pond 7.

In addition to the midge pOpulation there were other
organisms whose distribution and numbers varied consider-
ably among the ponds. Oligochaetes were numerous in Ponds
20 and 21, represented in Pond 7, but were quantitatively
not significant in Pond 12. The sand, Hyalella knicker-
bockerii, was fairly abundant in Ponds 20 and 7 and pres-
ent in Ponds 21 and 12 whereas the small mayfly, Caenis
sp., was found in.1arger numbers in Ponds 21 and 12 than
in Ponds 20 and 7. Leeches (Hirudinea) constituted a low
percentage numerically in all of the bottom samples but
swelled the volumetric percentages considerably in the
samples from Ponds 7, 12, and 21.

Very few dragonflies (AnisOptera) were taken in the
samples but they represented from two to five per cent of
the total sample volume of each pond. The large burrow-

ing mayfly, Hexagenia sp., was numerous in the bottom

 

 

II $E'IANEWS
ORGAFYIS'PB

 

   
 
     
   
   

Per cent by number

           

HEUUUIHW

Lessons
(26‘)

 

 

 

 

 

 

 

 

 

Per cent by volume

Chart II. - leposition of bottom fauna in dredge
samples from unfertilized Pond 7.

 

Per cent by amber

 

 

 

 

 

 

 

 

1mm

Discuss
(5311

 

 

 

“SIEMENS

  
  

ORGA‘TIS‘uB

Per cent by volume

Chat III. - Cmposition of bottom fauna in dredge
samples from fertilized Pond l2.

 

 

 

   

Per cent by number

 

ORGA"! $8

Per cent by volume

Chart V. - Composition of bottom fauna in dredge
samples from unfertilized Pond 21.

14

fauna of Pond 21 and present in Pond 7 but none were found
in Pond 12 and only two individuals were taken from Pond 20.

Other organisms represented in the bottom samples in
small numbers were damselfly nymphs (Zngpters), ColeOptera
larvae, immature forms of the mayfly, Baetis sp., caddisfly
larvae (TrichOptera), a few small molluscs (GastrOpoda and
Pelecypoda) and the water mite (Hydracarina). Two or three
LepidOptera larvae and several Diptera larvae, other than
midges, were also taken.

While crayfish.and tadpoles were present in all of the
ponds, and a few were brought up in the samples, they have
been excluded from consideration because it was felt that
the method of sampling used would not adequately sample
their numbers. The comparatively large volume of those few
taken.would unduly influence the total volume of the fish
food organisms thereby producing a volumetric total not
truly indicative of the pond pOpulation.

From the bottom sampling it appears as though each
pond had a bottom fauna composition more or less peculiar
to itself, thereby emphasizing the fact that no two bodies
of water are exactly alike. Swingle (1947) reported a
similar variation in the production of plankton.a1gae in 27
small ponds at the Alabama Experiment Station. Even though
the ponds had a common.water supply and were, morphologic-
ally, almost alike the ccmposition of the phytOplankton
varied from pond to pond.

Tables 2, 3, 4, and 5 have been prepared summarizing

Table 2. -.L summary of the Grades—sample data of'the unfertilized

Pond 7 and a tabulation of the bottom fauna in the samples.

 

 

 

 

 

 

 

 

Collection Date July August September Totals
No. of Samples 50 18 6 54
Total Sample Area 24.78 14.87' 4.96 44.60
(sq. ft.)
Total 30. Organisms 1515 611 84 2210
No. Crganisms/sq.ft. 61.14 41.09 16.95 49.46
TOtal V?1e grganlsma 1504 Ssh lob 2200
cc.

V01. Organisms/aq.ft. 062 e06 e26 049
Chironomidae A 775 51.02 248 40.57 48 57.14 48.52
B 2.9 17.68 1.1 16.42 .1 7.69 16.80

Ceratopogonidae A 50 1.98 10 1.64 1 1.19 1.85
B --- trace --- trace --- trace trace

Chaoborinae A --- ----- --- ----- 1 1.19 .05
B --- ----- --- ----- --- trace trace

Caenis A 245 16.17 52 8.51 --- ----- 15.42
B 1.1 6e71 03 4048 "' ‘‘‘‘ 5e74

Baetis A 5 .55 --- ----- --- ----- .25
B --- trace --- ----- --- ----- trace

Hexagenia A 6 .40 11 1.80 --- ----- .77
B 08 4088 1.0 14e95 "’ ‘‘‘‘ 7e68

Anisoptera A 5 .55 --- ----- --- ----- .25
B .8 4.88 --- ----- --- ----- 5.28

Lygoptera A 15 .86 21 5.44 --- ----- 1.54
B .2 leaz e1 le49 "‘ ..... 1.23

Trichoptera A 5 .20 9 1.47 5 5.57 .68
B --- trace .1 1.49 --- trace .41

Coleoptera A 41 2.71 10 1.64 6 7.14 2.58
B .5 1.85 --- trace --- trace 1.25

Lepidoptera A --- ----- --- ----- --- ----------
B --------- --- ..... --- CCCCCCCCCC

Other Diptera A 4 026 5 e82 --‘ ““- 041
B --- trace --- trace --- ----- trace

Hyalella A 261 17.25 182 29.78 7 8.55 20.54
, B 1.4 8.04 100 14e93 “" trac. 9084
fiirudinea A 22 1.45 6 .98 5 5.57 1.40
B 4.9 29.88 .2 2.99 1.2 92.5 25.82

hydracarina A --- ----- --- ----- 4 4.7 .18
B —-- ----- --- ----- --- trac trace

Cligochaeta A 52 2.11 5 .65 2 2.5 1.72
B 07 4.27 e3 4e48 '1‘ trac 4.10

Gastr°p0da A 25 1e65 25 4e09 3 5.5 2e40
. B 05 be05 e7 10e45 "’ trac 4.92
PelecyPOGB A 49 3023 27 4:42 6 7e1 $.71
B 1.8 10e97 05 7e46 "‘ trac 9043

 

 

A - Number of organisms and

per cent of all organisms by number.

B - Volume of organisms in cubic centimeters and per cent of all
organisms by volume.

I

 

 

Ifable 5. - d emery of the dredge-sample data of the fertilized

Pond 12 and a tabulation of the bottom fauna in the samples.

 

 

 

 

 

 

 

 

Collection Lute July August September Totals
Yo. or Samples 50 18 6 54
Tocul Sample drea 24.78 14.87 4.96 44.6L
(so. it.)
Total :0. Crganisms 512 956 176 5644
1.00 crganiSULS/sge 1.30 1010427 040:9 £45048 £1079
lotal Vol. (rganisms 52.1 19.9 1.6 56.6
(cc.)
V010 crganiSILlS/BKefte 10(10 1004 00L 1.er
Chironomidae A 2205 87.68 791 82.74 117 66.47 85.24
Ceratopogonidae A 4 .16 10 1.05 --- ----- .58
B. ---- trace --- trace --- ----- trace
Chaooorinae n ---- ------------- 14 7.9; .6L
5 ---- ------------- --- trace trace
Caenis 1 115 4.50 4C 4.18 --- ----- 4. 9
3 00 1070 0‘5 080 "" ..... 104/0
3861318 A 7 028 """""" '-’ .... 01.9
. B ---- trace -------- --- ----- trace
hexagenia 1 ---- ------------- --- ----------
3 ---- .............. --- ..........
AniSOP’cel‘a 2.1 13 052 d 0h]. 10 5068 008
B 104 4012 "’" trace 02 12050 ~.e&:
Zngptera A 18 .72 v .51 7 5.96 .77
' B .3 .88 --- trace --- trace .51
Trichoptera A 2 .08 7 .75 1 .57 .57
B ---- trace .1 .45 --- trace .17
ColeOptera A 22 .88 10 1.65 2 1.14 .95
B 06 . 088 “‘ EraCb -‘- 0130: 001
LepiLOptera A l .04 -------- --- ----- .su
B ---- trace -------- --- ----- trace
Other niptera A 2 .08 8 .84 --- ----- .17
B ---- trace .1 .45 --- ----- .17
Hyalella A 47 1.87 25 2.62 1 .57 2.06
B 01 029 01 045 --- trace 034
Hirudinea A 56 2.25 56 5.77 --- ----- 2.5;
B 1704 51018 1508 59048 ." ..... ‘3)00U4
hydracarina A 5 .04 4 .51 1 .57 .14
B ---- trace ---- trace --— ----- trace
Oligochaeta A 7 .28 1 .10 --- ----- .21
B ---- trace --- trace -4- ----- trace
GastrOpoda 1 2 .08 11 1.15 12 6.82 .69
3 01. 029 --‘ trace 0]. 0025 .u4
EelecyPOGa A 11 04.4. 8 084 11 0025 04 :1:
3 .6 1070 05 1029 00 U7oéL £055

 

 

A - Number of organisms and per cent of all organisms by number.

B - Volume of organisms in cubic centimeters and per cent of all
organisms by volume.

 

 

Table 4. - A sumsry or the dredge-sample data or the fertilized
Pond 20 and a tabulation of the bottom.rauna in.the samples.

 

 

 

 

 

 

 

 

 

 

 

Collection Dat0 June July Annust September Totals
No. of Samples u . 35 28 - 7 7“
Sq. ft. 4
Total No. Organism 232 31:51 was 352 5680
"00 m1!” ICQ0 ft. 7003 119037 79077 60090 96020
“tal‘VOI; Organisms 301 3605 1808 “03
000
Vol. Organisms/sq. ft.
Chironomidae A 136 58.62 .
B .3 25.31 19.1 51.19 6.6 30.27 1.6 20.00
Ceretonogonidae A 3 1.30 ”5 1.30 139 7.53 M3 12.21
B tre tre 01 027 0" 10d} 01 10:55
ChQObonna. ‘ -D.’ ..... -O- ..... -C- ..... -C- .....
B ---- ....- ---' - .... --- ..... ---
cum. A 5 2.16 .162 M66 59 3.20 2
B _tr0 tr0 0 7 1088 02 092 tre
Baetis .A 17 ..M9 .3 .16 1
B .3 .80 r. tr. tr.
Hexnsenie , .A 1 .b3 1 .03 --- ..... --- .....
B 01 3023 0} 080 "- -"""- "’- ....
”not“! A ----- 10 .29 142 2.23 27 7.67
o B O--- ..... tr0 tr. 02 092 01 106
mscptera A 1.30 17 .119 1 .03 6 2.27
' B 10 H5 016 1 08 ’4 082 tr. tre 03 3
TrichOptera ~ A ----‘ ----- 1 .03 13 .70 u» -----
s ..-- ----- tr. tr. .1 .us ..-- .....
ColeOptera A 9 3.33 1m 1.27 36 1.95 3
B .3 9.68 .7 1.8.7 .2 .92 tr.
Corixidee A ---- ----- --- ----- --- ----- --- -----
B ..-- ..--- --- ----- --- ..... --- .....
Lepidcptern A. p--- ----- --- ----- --- ----- h 1.1“
B ---- --... -- ----- --- - ---- .1 1.25
Other Diptorl A h... 0.---.. 7 020 10 0219 5 1.112
. s .--- ....-- .20 1.07 tr. tr. .3 3
83010110 A. 19 8.19 R30 12.”) 309 16.75 50 1
s .2 6.15 3.5 9.38 1.9 6.72 .1 1.25
Hi 31111100 A “- O.... 23 066 1 0811 11 3 012
a --- - .... 1.6 11.23 1.1 5.011. .5 6.25
Hydracerina A --- ----- .9 ‘ .09 20 .98 h
. B --- ..... tr. ‘ tr. tr0 tr. tr.
Oligcchaeta A 56 211.111 "69 13.55 5"!) 29.5!2 97 27.55 -
B i 0} 9066 6.0 16008 607 30073 08 10.00
Nmtcda’ A --- ..--- h .12 --- ------- --- .....
B --- --g-- .1 .27 --- ----- --- -..--
Gaatmpoda A 09-- ----- 73 2 011 66 3038 Is 5 011
n ------- 1.7 11.56 1.11 6. 2 .I' 5.
Pelecypods A an ----- --- ----- -- ----- * --- ----
B

 

 

 

¥ - ‘mfll

A - Number of organisms
B - Volume of organisms
organisms by volume.

and per cent of all organisms by number.
in cubic centimeters and per cent of all

 

 

Table 5. - A summary of the dredgaaample data or the unfertilized

Poul 21 a!!! u tabulation of the bottom fauna in the samples.

 

 

 

 

 

 

 

 

 

 

 

Collection but. Juno July August ' Swimmer watch
'0. of 36‘1” n ’ 35 28 7 7“
MC: SEWIO)A1‘I 3 a” 28 091 23 013 5 078 61 012
Sq . ft .
mom No. Organica- 105 1033 92': 296 2565
lo. WIN/”o”. 31082 ”073 ”0” 510” ”0%
166.1(761). Organim 5.1 no.2 15.7 1.7 60.6
0° 0
W1 0 m1 “II-Q0” o 09” 10” 0“ o” 099
0111 mud“ A 3 2.86 100 10 .82 18 6.014 6.96
B n. “no. on 1 098 01 h 076 1 o“
contopogomau - A 1 .95 an M76 u 1.51l 3.76
B - tnoo -.. trac. ... true .15
01111050an. A ... ....- 83 8.98 230 77 .17 13.21
B O“ m“ 02 o” 06 28 057 1 021
“.311 3 A 3 2 .86 159 17 02° 1 o 19 050
B -- true. .5 2.16 -- trac. 2.67
nutu A - ---- 2 .22 -.. ....- .30
B ..- ....- ... tnoo «- ....- true.
mm.“ B A 20 19 o” 3” 3 a“ 1 03"; 7 051
B 1.1 n .118 1k]. 200” .0. ‘1'.” 22002
3 CW- trace .3 1 0.” 02 9 .52 h 007
Zymton A ... ..... 27 2.92 3 1.01 1.60
B -0. “0.. 01 050 0-- tn“ .1,
Mahayana A 2 1.90 114 1.51 -.. ....- 1.10
B o 1 3 .23 01 050 --" 0.... .75
0010033001! A .0- CC... 5 .5” m ..C“ 1 .01
a m ....- «- true. «.- ----- .115
00111106. A --- ...-- ... «- -- --..- .13
B ..- --- ..- ---- -- --- t no.
Lopidoptora A --- --- -.. ...-- -.. ---- true.
B --- ---- ... -...- - ---—- .01:
”0611» Diptera A «- mu 5 .5” ..- ---- 1.90
B O.- o...- 0.- trace .0- .m0 1 081
”.1011. A 1 o” 22 2 a” m M u .00
a ... truce no true. - ..... J15
1!. M13“ A O.- ....- 1h 1 051 u 1 03” 1 on
B «In-- c...- u 03 21 029 -.. $800 27 01"
nydraoarinu 'A -- ..--- 17 1.63 5 1.66 1.27
B «- ...-- -- taco ... true true.
01130011116“ A 6" $095 89 23002 8 2 .63 a .62
' a 1.6 56.06 11.6 25.76 .6 26.57 26.69
Nomtoda A ..- ....‘- “- --- .. ..-.. --— .--- ----
B -3. us... no. con-d o.- -.00- o.- -ooo- o..--
muro-soaa A ‘10 9.52 . 119 11".?" 151 111.17 16 6.014 6.76
a .1 3.23 .5 1.22 .9 11.1.16 .2 9.52 2.56
Blooypoda A ..- ...... 1 .10 1 .11 -.. ----- .06
B ..- ----- ..- truce '--- tag. on —--- truce

 

 

A - We: of organ-u
P - Volum of organism
organism by voluu.

and per cent of an organism by number.
in cubic continuum and p01- oont of an

 

 

15

the sampling data by months for each pond. A monthly summary
of the bottom fauna taken in the samples is included showing
the numbers, per cent of all organisms by number, volume, and
per cent of all organisms by volume.

The total bottom fauna production for each pond, as cal-
culated from the dredge sampling of the standing crop of or-
ganisms, is presented in Table 6. The computations show that
the fertilized Pond 20 produced 16 per cent more invertebrate
organisms than did the unfertilized Pond 21 and the fertil-
ised Pond 12 produced 136 per cent more invertebrates than
the unfertilized Pond 7.

However, in order to present a more accurate picture of
the potential fish food production of these ponds, the fig-
ures were revised, omitting the leeches and oligochaetes as
they were seldom taken as feed. This is believed Justified
not only from the results of file stomach analyses presented
here but also from results reported in the literature (Ben-
nett, Thompson, and Parr, 1940; Leonard, 1940; Howell, 1941;
Ball, 1948). This revision, shown in the second column of
Table 6 shows that the fertilized Pond 20 produced 91 per
cent more food organisms of a size used by small fish than
did Pond 21, and Pond 12, also fertilized, produced 50 per
cent more food organisms found in the diet of snall blue-
gills than did Pond 7. In each instance the ponds that were
treated with fertilizer had a greater standing crop of
benthic organisms than did the untreated ponds.

Table 6.- Comparison in pounds per acre of total bottom

fauna with the production of organisms found in the diet

of bluegills in fertilized and unfertilized ponds.

 

Pounds per acre

 

 

Pond Total bottom fauna Food organisms**
Pond 20‘ 92 71
Pond 21 79 37
Pond 12* 92 4s
Pond 7 39 32

 

 

 

 

* Fertilized pend.

** Oligcchaetee and leeches omitted.

 

 

16

STATISTICAL ANALYSIS

In a quantitative analysis of this sort a statistical
approach is highly desirable although not always essential.
As Lyman (1943) pointed out "Biological research from the
quantitative angle does not in all situations lend itself
to statistical analysis.... Indications and trends are
often as useful as absolute values.“ However, an attempt
was made to offer mathematical support of the results ob-
tained in this experimmt by analyzing the variance of the
data.

Leeches and oligochaetes were omitted from the data
in order that the tests could be made on the population of ’
the organisms generally found in me diet of the bluegill.
The null hypothesis to be tested was that the data from
each pair of experimental ponds are random samples from s
common population. If the test is significant the vari-
ance in the data is not due to the sampling but rather
that the populations in the fertilized and unfertilized
ponds are different.

Fisher's 'F' test of significance (Snedecor, 1947)
was appliedfite'the weekly sample data of Ponds 20 and 21.
The ‘1" ratio of the volumetric data was 5.52 with l and
20 degrees of freedom'which is significant at the 5 per
cent level. The test of the numerical data showed a
ratio of 11.55 with 1 and 20 degrees of freedom which is
highly significant at the l per cent level. The first

17

test indicated that there was less than one chance in 20
that the samples were drawn from the distribution specified
in the hypothesis while the results of the second test
showed that there was less than one chance in 100 that the
samples were drawn from the distribution stated in the hypo-
thesis. Evidently the pOpulation of organisms in the fer-
tilized and unfertilized ponds was different. Since fertil-
ization was the factor tested in these experiments, the sig-
nificantly greater invertebrate pOpulation of the fertilized
Pond 20 over that of the unfertilized Pond 21 can be attrib-
uted to the application of fertilizer.

The '1!" ratios obtained from testing the data of Ponds
7 and 12 were 1.38 for the volumetric data and 2.99 for the
numerical data, both with l and 16 degrees of freedom.
Neither tests were significant so that the null hypothesis
was not disproved. The individual variations among the
data within each pond were too great for the small number
of samples taken. mere samples would be required for a
statistically positive test.

Although the results were not mathematically support-
ed, indications of a greater production of bottom fauna in
the fertilized Pond 12 than in the unfertilized Pond 7 can
be demonstrated. In addition to the computations already
presented in Table'6, Charts VI. VII, VIII, and II have
been prepared to show the results and fluctuations in the
weekly bottom sample data. Charts VIII and IX show a con-
siderable difference in the production of food organisms in

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18

the fertilized Pond 12 over that of the unfertilized Pond 7.
Ball (1948) has shown from his work on Third Sister
Lake, Michigan, over a three-year period that there is an
annual cycle in the bottom fauna production. The organisms
reach a peak in abundance in January after which their num-.
bers decline until a low point is reached somewhere around
the end of June or the first week in July. At this time
the population again starts to rise toward the winter peak.
From the charts it appears as though there was an interrup-
tion in the normal upswing of production in the experiment-
al ponds at Wolf Lake. This can be accounted for by at
least two factors. One was the effects of predation by the
young bluegills which had reached an active foraging size
at this time. The other was an emergence of the numerical-
ly dominant midges. The predatory activities of the fish
presumably kept the bottom fauna pOpulation in check the

rest of the summer.
STOMACH ANALYSIS

The measurements of the bluegills taken for this food
study ranged between 1.3 and 2.6 inches (total length).
most of the stomachs contained at least some undigested or
partially digested material, there being only 19 of the 503
examined that were empty. Chart I presents the principal
organisms taken as food by the young-of-the-year bluegills,
showing each organism as the per cent of the total number

of organisms taken and the percentage of stomachs contain-

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l9

ing the organism.

IMidge larvae and pupae were found to be the principal
item in the omnivorous diet of these fish. Chironomidae
and CeratOpogonidae constituted 48 per cent of the total
number of organisms, the former occuring in 73 per cent of
all stomachs containing food. Midges are apparently one
of the staple items of food for these young fish. This is
further borne out by the fact that at the time of capture
85 per cent of the bluegills were feeding on these insects
in the fertilized ponds while about 60 per cent of the
fish in the unfertilized ponds were feeding on them.

Next, in numerical importance, were the Ostracoda
which made up 25 per cent of the total number and were
taken by 47 per cent of the fish. The scud, gyalella
knickerbockeri, and mayfly, Caenis sp., were each taken by
29 per cent of the bluegills, both.forming roughly 5 per
cent of the total number of organisms. Water fleas
(Cladocera) comprised 6 per cent of the total number but
were taken by only 18 per cent of the fish. Twenty per
cent of the stomachs contained caddisfly larvae (Tri-
chaptera)., Other invertebrates found in the stomachs
were copepods, damselfly nymphs (Zngptera), snails, may-
fly nymphs of the genus Baetis, water mites (Hydracarina),
beetle larvae (ColeOptera), water boatmen (Corixidae), and
one leech. ‘

Tables 7 and 8 are summaries of all the material taken

by the 503 bluegills examdned, each organism being tabulat-
ed as per cent of the total number of organisms along with

fable 7.42he food of 230 young-of-the-year bluegills which

were taken.frem.Pond 7 and Pond 12.

Average total

 

length-1.86" (Range 1.3-2.3 inches).

 

 

 

 

POED 12 POND 7
(fertilised) (unfertilized)
Per cent Per cent
Per cent of Per cent of
of all stomachs of all stomachs
organisms containinglorganisms containing
organisms organisms
{MOLLDSGA
Snails 1.71 15.13 1.44 9.00
MILLCOSTRAGA
23818118 2.36 26.05 7.38 30.63
EETOMDSTRLGL
Cladocers 8.46 30.25 8.26 27.93
Ostrecode 36.28 58.82 9.54 29.73
Gopepods 4.02 29.41 1.52 9.91
.LQHATIO INSECTS
Ridges:
Chironomida. 350 61 84 087 51024 68016
CeratOpogointdlo 4035 33 0 62 202‘ 14 041
Ephemerida:
0881118 107’ 26005 8082 4005‘
Baetis .19 2.52 .24 2.70
Odonata:
niaoptem 011 2058 016 1080
Zngptera 2.98 15.97 1.68 14.41
Nichoptera 082 13 04‘ 5005 25023
0°1eopt°m 034 4020 024 1080
Hemiptere 4.02 29.41 .88 4.50
Other Diptera .11 2.52 ----- -----
TERRESTRlAL INSECTS .04 .84 .08 .90
121828181 " ' .11 1.68 .16 1.80
HIDRAGARIRA .78 11.76 .48 4.50
18:82 ‘ ’ ----- ----- .08 .90
0LIGOCHAEIA .04 .84 ----- -----
menarche ' .07 1.68 .16 1.80
oneiric'onssxs -~--- 3.36 ----- 6.31
InoRcAnxc 888218 ----- 21.00 ----- 15.32
vEGEIAIIon' ' ----- 1.68 ~---- 8.11
ALGAE .' ----- 9,24 ----- 3,50

 

 

 

 

 

 

 

Table 8.-The food of 273 young-of-the-year bluegills which
were taken from Pond 20 and Pond 21. Average total
length-1. 91" (Range 1.3-2.6 inches).

 

 

 

 

 

 

POND 20 POND 21
(fertilized) (unfertilized)
. Per cent Per cent
Per cent of Per cent of
of all stomachs of all stomachs
organisms containing organisms containing
organisms organisms
MOLLUSCA
Snails .18 2.21 1.16 5.84
Clams .12 1.47 .06 .73
MALACOSTRACA
Hyalella 9089 46032 1090 13087
ENTOMOSTRACA
Ostracoda 26.30 48.52 15.01 49.63
Cladocera .78 5.15 4.72 13.14
COPQPOda 1069 5088 025 2019
AQUATIC INSECTS
Midges:
Chironomidae 48.13 86.02 52.20 59.85
Ceratopogonidae 4.71 25.00 .98 9.49
Ephemerida:
Caenis 1.33 9.56 12.81 42.33
Baetis .60 5.15 1.23 7.30
Hexagenia 006 07‘ 012 1046
Odonata
AnisOptera .18 2. 21 .06 .73
Zngptera .54 5. 88 2.59 13.14
Trichoptera 2.29 19.85 4.84 20.44
Coleoptera .30 3. 68 .31 3.65
Hemiptera .36 3.68 .12 1.46
Other Diptera 084 9056 043 2092
181052181 .18 2.21 .98 8.03
HYDRACARIHA 1.51 11.03 .43 4.38
ORGANIC DEBRIS ----- 24.26 ---- 9.49
INORGANIC DEBRIS ----- 2.94 ---- 7.30
7288111105 ' ----- f 12.50 ---- 13.14
ALGAE " ----- f 6.62 ---- L 2.19

 

 

 

 

 

 

 

20

the per cent of stomachs containing the item. The heading
"Vegetation" refers to the leaf and floral parts of higher
aquatic plants presumably taken in along with some organ-
ism as they were always a minor item in the 46 stomachs in
which they were found. This seems to be also true for the
fragments of filamentous algae and EEEEE.SP° which were
found in 27 stomachs. Animal matter which was unidentified
has been classed as organic debris. Leonard (1940) pointed
out that the proportion of various organisms represented in
the debris is about in direct ratio to their abundance among
recognizable organisms and need not be considered in calcu-
lating the percentage composition of the stomach contents.

The percentage of occurence of the organisms in the
stomachs of the bluegills may be interpreted as the percent-
age of fish feeding on the organism at the time of capture.
Twenty per cent or more of the fish were taking individuals
from at least one of the following groups: Entomostraca,
sends, midges, mayflies, and caddisflies. Therefore it is
important to note that these organisms thrive and multiply
rapidly in fertilized ponds to a greater extent than in un-
fertilized ponds.

One criterion of measurement in fish food studies is the
‘forage ratio' suggested by Hess and Swartz (1940). This
factor is a ratio of the percentage of occurence of an org-
anism in the population to its percentage of occurence in the
stomach of the fish. If the ratio of a group of organisms
varies significantly from one, it should be due to either a

difference in availability or a difference in preference.

21

Allen (1942), offering the term 'availability factor'
for the forage ratio, states that in order to obtain a true
estimate of the actual quantity of fish food any fauna rep-
resents, one must consider differences in availability to
the fish. Therefore the forage ratios have been computed
for four principal organisms that were found both in the
bottom samples and in the stomachs and are presented in
Table 9. These-ratios would seem to indicate that the or-
ganisms were available to the fish but that only in Pond 21
was any preference indicated and that was for the midges.
Leonard (1941) suggested that the forage ratio be used as a
measure of availability only. In view of this criticism,
the midge ratio for the unfertilized Pond 21 would indicate
instead that they were not readily available to the fish.

DISCUSSION

Cuisiderable work has been done in measuring the
standing crop of bottom fauna of streams and lakes (Adam-
stone and Harkness, 1923; Surber, 1930; rate, 1931; Need-
ham, 1934; Tarzwell, 1938; Cooper, 1941; and Ball, 1948)
but very little has been dune on ponds. Meehean (1936), re-
porting on bass production in.Louisiana ponds, stated that
with the application of fertilizer the bottom:fauna in.the
ponds reached a production of 105 pounds per acre. H. E.
Howell (1942) demonstrated in.Alabama ponds that the addi-
tionpffertilizer more than trebled the average dry weight
of the bottom organisms. Ball (1948) converted Howell's
results to a pounds per acre basis to show that the fertil-

Table 9.-Forage ratios of four organisms found in the diet
of bluegills and the per cent composition by num-
ber of the organisms in the bottom samples and
bluegill stomachs.

 

 

 

 

 

 

 

Midges mayflies Scuds Damselflies

POND 20

Per cent in samples 54 4 14 1

Per cent in stomachs 48 2 10 .5

Forage ratio .9 .5 .7 .5
POND 21

Per cent in samples 11 28 4 2

Per cent in stomachs 52 14 2 2

Forage ratio 4.7 .5 ’.3 1
POND 12

Per cent in.samp1es 85 4 2 1

Per cent in stomadhs 39 2 2 3

Forage ratio 0.45 .5 1 3
POND 7

Per cent in samples 50 13 20 2

Per cent in stomachs 53 9 7 2
Forage ratio 1.1 .7 .35 1

 

 

 

 

 

 

22

ized ponds produced approximately an average standing in-
vertebrate crop of 98 pounds per acre and 28.8 pounds per
acre in the unfertilized ponds.

Howell's results compare favorably with those obtain-
ed in this eXperiment in which it was also shown that the
bottom fauna production of the fertilized ponds was great-
er than that of the unfertilized ponds. Table 6 showed
that both the fertilized Pond 20 and Pond 12 had a stand-
ing cr0p of bottom fauna of 92 pounds per acre whereas the
unfertilized Ponds 21 and 7 had respectively 29 and 39
pounds per acre of benthic organisms.

The results of these investigations indicate that the
application of fertilizer in proper amounts will increase
the standing crop of bottom organisms. Other evidence
presented in this paper showed that fertilization had lit-
tle effect on the total hardness of the pond waters nor
was it possible to produce a plankton bloom until late in
the summer in ponds with submerged beds of higher aquatic
plants. Instead of a plankton bloom a heavy growth of
filamentous algae was produced which resulted in eliminating
most of the submerged higher aquatic plants although it had
little effect on Anacharis sp.

It was also demonstrated that fertilization favors
the production of organisms used as food by young-of-the-
year bluegills. Fisher's 'F' test of analysis of fariance
was applied to the sample data of the standing crop of

these fish-food organisms to show that the variance in the

-.—a—.. ..--

‘r--.

L. -

23

data was not a sampling variation but rather one of pOpula-
tion differences between the fertilized and unfertilized
ponds. Both significant and highly significant results
were obtained on the data from Ponds 20 and 21.

The results of the food analysis of the young-of-the-
year bluegills compare favorably with previous studies.
Pearse (1918), Leonard (1939), Bennett, Thompson and Parr
(1940), and Howell (1941) all agree that entomostracans
and midges form the chief articles of diet of the young
bluegill. Chironomids, Ostracoda, and small mayfly nymphs
were the principal items in the diet of the small blue-
gills in these experimental ponds. Leonard sums up the
food of all sizes of bluegills from his work on Ford Lake,
Michigan in this manner: "members of the group of smallest
fish (15-26 mm.) fed almost exslusively mu plankton, small
mayfly nymphs, and chironomids. Plankton, Chironomids, and
aphids bulked about the same in the group of middle-sized
fish (33-50mm.) but the Odonata were almost as abundant.

The largest specimens (105-130 mm.) fed on anisoptera drag-
onfly nymphs almost to the exclusion of other groups."

Howell (1941) and 3411 (1948) observed that the phantom
midge Chaoborus was not taken by the bluegill and this was
true in Pond 21 where these midges were becoming increasing-
ly abundant at the end of the summer but were not found in a
single stomach.

Howell, Swingle, and Smith (1941) reached the conclu-
sion that bluegills resorted to plant foods only when the

2‘

supply of invertebrates was reduced, apparently preferring
the animal food. This was corroborated by the work of Bell
(1948). The young bluegills in these experimental Ponds at
Wolf Lake fed almost exclusively on animal foods, vegeta-
tion being only incidental items of food in a few stomachs.
ENidently in all of the ponds the young bluegills had an
abundance of invertebrate food organisms upon which.to feed.

The weekly data on the stomach contents revealed a
definite change in the diet of these young fish about the
time they had reached a length of almost two inches. At
that time their principal food changed rather markedly from
entomostracans, sends and small mayfly nymphs to a diet in
which midges were most important.

The application of fertilizer to small Michigan ponds
is desirable in that it will indirectly increase the food
supply of thefish. Inasmuch as it is generally accepted
that food is a limiting factor in fish production, this in-
crease of bottom fauna by fertilization and its utilization
by the fish should result in an.increased production of
fish.

'Swingle and Smith (1939) demonstrated, from their work
in Alabama, that by applying inorganic fertilizer in proper
amounts to a pond they could increase the production of
bluegill bream (Lepomis macrochirus) from 130 pounds per
acre to between 300 and 500 pounds per acre. That these
results can.be equalled in.Mlchigan has not been demonstrat-

ed. Local conditions such as fertility of the soil, length

25

of the growing season, and characteristics peculiar to the
individual pond have to be taken into consideration.

In Illinois, Bennett (1946) reported that from a sur-
vey of 22 small, unfertilized bodies of water it was found
that they supported fish pOpulations varying from 71 pounds
per acre in a new pond on a sterile site to 1145 pounds per
acre in an old oxbow lake.

It was shown in this investigation that the ponds used
for this experiment, although physically quite similar,
proved to be biologically quite different as shown by the

composition of the flora and bottom fauna.

SUMMARY

1. The standing crop of bottom fauna of two fertil-
ized and two unfertilized ponds was measured and com-
pared. The two fertilized ponds showed 16 and 136
per cent greater production of organisms respectively
than the corresponding unfertilized ponds.

2. A.similar comparison between.the two pairs of
ponds showed that the fertilized ponds produced, re-
spectively, 91 and 50 per cent more of those food
organisms important in the diet of the bluegill than
did the unfertilized ponds.

3. Fisher's "F" test of analysis of variance, ap-.
plied to the data, demonstrated a significant differ-
ence in the production of bottom fauna of one of the
fertilized ponds over the production of its untreated

control pond.

4.

5.

6.

7.

9.

10.

26

The application of fertilizer produced a heavy
growth of filamentous algae throughout most of the
summer. This resulted in eliminating most of the
submerged higher aquatic plants in Pond 12 and Potamo-
ggtggycrispus in Pond 20 but did not seem to affect
Anacharis sp.

Stomach analyses were made on 503 young-of-the-
year bluegills. There was a marked change in their
diet from entomostracans to midges when they reached
a length of about two inches. There was no evidence
that the fish were eating vegetation indicating that
a sufficient animal food supply was available in all
of the ponds.

The application of fertilizer to small ponds in
Michigan is desirable in that it will indirectly in-
crease the food supply of the fish, which is one of
the limiting factors in fish production.

The evidence presented from this investigation
shows that fertilization favors the production of
organisms used as food by young-of-the-year bluegills.

Although physically quite similar the ponds
proved to be biologically quite different as shown by
the composition of the flora and bottom fauna.

In ponds with submerged beds of higher aquatic
plants it was impossible to obtain a plankton bloom
until late in the summer even though the amount of
fertilization was varied considerably.

Fertilization had little effect on the total

hardness of the pond waters.

27
LITERATURE CITED

Adamstone, F. B. and W. J. K. Harkness
1923 The bottom organisms of Lake Nipigon. Univ.
Toronto Studies. Biol. 22. Pub. Ont. Fish.
Lab. 15.
Allen, K. Radway
1942 Comparison of bottom faunas as sources of
available fish food. Trans. Am. Fish. Soc.,
1941 Vol. 71, pp. 275-283.
Ball, Robert C.
1948 Relationship of Lake productivity to total
fish production and to fish feeding habits.
Tech. Bull. 206, Michigan State College Agr.
Exp. Sta.
Bennett, George W.
1946 Fertilizers in fish pond management. Mimeo.
leaflet of Ill. Nat. Hist. Surv. 2 pp.
Bennett, Geo. W., David H. Thompson, and Sam A. Parr
1940 A second year of fisheries investigations at
Fork Lake, 1939. 111. Nat. Hist. surv.
Biol. Notes No. 14, 24 pp.
Cooper, Gerald P.
1941 A biological survey of lakes and ponds of
the Androscoggin and Kennebec River drain-
age systems in mains. Fish. Surv. Rept.

No. 4, mains Dept. Inland Fish. and Game.

28

Davis, H. S.
1938 Instructions for conducting stream and lake
surveys. Fisheries Circular No. 26, pp. 1-55,
U. 8. Bureau of Fisheries.
Davis, H. S. and A. H. Wiebe
1930 EXperiments in the culture of the black bass
and other pond fish. Rept. U. S. Comm. of
Fisheries, 1930, Appendix IX, pp. 177-203.
Hess, A. D. and Albert Swartz
1940 The forage ratio and its use in determining
the food grade of streams. Trans. Fifth N. A.
Wildlife Conf., pp. 162-164.
Hogan, Joe
1933 Experiments with commercial fertilizers in
rearing largemouth black bass fingerlings.
Trans. Am. Fish. Soc., Vol. 63, pp. 110-119.
Howell, Henry H. v
1942 Bottom organisms in fertilized and unfertil-
ized fish ponds in Alabama. Trans. Am. Fish.
Soc., 1941 Vol. 71, pp. 165-179.
Howell, H. H., H. S. Swingle and E. V. Smith
1941 Bass and bream food in.A1abama waters. Ala-
bama Cons. Vol. 1, No. 4, p. 3.
Leonard, J. W.
1940‘ Further observations on the feeding habits of
the Montana grayling and bluegill in Ford
Lake, Mich. Trans. Am. Fish. Soc., 1939 Vol.
69, pp. 244-256.

29

\Leonard, J. W.

1941 Some observations on the winter feeding habits
of brook trout fingerlings in relation to nat-
ural food organisms present. Trans. Am. Fish.
Soc., 1941 Vol. 71, pp. 219-227.

Lyman, F. Earle

1943 A.pre-impoundment bottom-fauna study of Watts
Bar reservoir area (Tennessee). Trans..Am.
Fish. Soc. 1942 Vol. 72, pp. 52-62.

Lyman, F. Earle and Jack S. Dendy

1943 .A pre-impoundment bottom-fauna study of Chero-
kee Reservoir Area (Tennessee). Trans. Am.
Fish. Soc. 1942 Vol. 73, pp. 194-208.

,Meehean, 0. Lloyd

1933 The role of fertilizers in pondfish culture.
Trans. Am. Fish. Soc., 1932 Vol. 63, pp. 103-
109. ‘

1936 Some factors controlling largemouth bass
production. U. S. Bur. Fish., Prog. Fish-Cult.,
No. 16, pp. 1-6.

Needham, P. R.

1934 Quantitative studies of‘stream.bottom foods.
Trans. Am. Fish. Soc., 1933. Vol. 64, pp.
238-247.

Pate, V. S. L.

1931 "Studies on the fish food supply in selected

areas". A biol. surv. of the Oswegatchie and

Black river systems. Suppl. 21st. Ann. Rept.,

30

19500 State Of N0 Y0 Cons. Deptep PP. 133‘1490

Pearce, A. S.

1918

The food of the shore fishes of certain Wiscon-
8111 lakea0 U0 Se Bur0 Fishe Bulls, V01. 35,
Pp0 247-2920

Richardson, R. E.

1921

The small bottom and shore fauna of the middle
and lower Illinois River and its connecting
lakes. Bull. Ill. Nat. Hist. Surv., Vol. 13,
pp. 362-522.

Smith, Es V0 and H0 80 877111ng

1939

1941

The relationship between plankton production
and fish production in ponds. Trans. Am. Fish.
Soc., 1938 Vol. 68, pp. 309-315. I
The use of fertilizer for controlling several
submerged aquatic plants in ponds. Trans. Am.

Fish. Soc., 1940 vo1. 71, pp. 94-101.

Smith, M. w.

1934

1934

Physical and biological conditions in heavily
fertilized water.g Joann. Biol. Bd. Canada,
vol. 1, pp. 67-93. '

The dissolved oxygen.contont of'fertilized
waters. Trans. Am. Fish. Soc., 1933 Vol. 64,
pp. 408-415.

Snedecor, George W.

1947

Statistical methods. Iowa State College Press,
.Ames, Iowa. 485 pp.

 

31

Surber, E. W.
1931 ,A quantitative method of studying the food of
small fishes. Trans. Am. Fish. Soc., 1930 Vol.
60, pp. 158-163.
1937 Rainbow trout and bottom fauna production in
one mile of stream. Trans. Am. Fish. Soc.,
Vol. 66, 1936. pp. 193-202.
Swingle, H. S.
1947 Experiments on pond fertilization. Ala. Exp.
Sta., Ala. Poly. Inst. Bull. No. 254. 23 pp.
Swingle, H. S. and E. V. Smith
1942 management of farm fish ponds. Ag» Exp. Sta.,
Ala. Poly. Inst. Bull. No. 254. 23 pp.
Tack, P. I. and W. F. Morofsky
1946' A preliminary report on farm pond management
in Michigan. Mich. Ag. Exp. Sta. Qt'ly Bull.,
Vol. 28, No. 4, May.
Tarzwell, Clarence M.
1938 Factors influencing fish food and fish pro-
duction in southwestern streams. Trans..Am.
Fish Soc., 1937 Vol. 67, pp. 246-255.
Tester, A. L. I
1932 Food of the small-mouthed black bass (ygpggy-
pterus dolomieu) in.some Ontario waters. Uhiv.
Toronto Studies No. 36. Pub. Ont. Fish. Res.
Lab. No. 46, pp. 171-203.
Welch, Paul S.
1935 Limnology. McCrawAHill Book Co., New'York,
N. Y. 471 pp.

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