EOL EES aN
Aa
canbiicasinc aS 8
el ei eesania sn Reese
2: a

ies

rh

es
Sh genet

iS
Ta eek

ria
sy ehhh SAY

Cree tert aes
eee pent
“es

Go

Snax:

as

A earn
STS Sad
Oat:

NATURAL HISTORY.
SURVEY.

STATE OF ILLINOIS

Henry Horner, Governor

DEPARTMENT OF REGISTRATION AND EDUCATION
John J. Hallihan, Director

LAKE MANAGEMENT REPORTS

3. Lincoln Lakes near Lincoln, Illinois

David H. Thompson

and

George W. Bennett

Printed by Authority of the State of Illinois

NATURAL HISTORY SURVEY
Theodore H. Frison, Chief

Biological Notes No. 11 Urbana, Illinois August, 1939

FIG. 1.--Bathing beach at Lincoln Lakes built by the Lincoln Sand
and Gravel Company. (Photo by Herbert Georg Studio.)

FIG. 2.--Above, a winter view of Lincoln
Lakes, showing wooded shores,

FIG. 3.--Right, member of Logan County
Sportsmen’s Club with largemouth bass from
Sportsmen’s Lake, 1938,

LAKE MANAGEMENT REPORTS
3. LINCOLN LAKES NEAR LINCOLN, ILLINOIS

David H. Thompson and George W. Bennett
Illinois Natural History Survey

Lincoln Lakes are a series of water-filled gravel pits in the floodplain of Salt
Creek, about a mile south of Lincoln, Illinois, They have been dug since 1905 by the
Lincoln Sand and Gravel Company. The water area of these lakes is now about 100 acres.
They are irregular in shape, and most of the wide-waters are connected by deep channels.
The gravel company has developed a bathing beach, cottage sites and other recreational
facilities for the general “se of the community. At the present time, Lincoln Lakes
constitute about one-half of the total water area of Logan County, in central Illinois,
and furnish the most convenient outdoor recreational spot for the residents of Lincoln,
a city of 13,000.

The water of Lincoln Lakes is clear and attractive for bathing, boating and fish=
ing. The lakes are partially inundated at intervals of one to several years by flood
water from Salt Creek. At such times the turbidity is increased, although the turbid
condition remains for only a short period. As will be shown later, hook-and-line fish
of sizes attractive to fishermen make up about 19 per cent of the total weight of fish
in these lakes. Furthermore, an unusually large proportion of these fish are bass of
large size. These fish do not take the hook readily, however, and fishing in Lincoln
Lakes is considered poor.

Early in 1938, the gravel company permitted the Logan County Sportsmen’s Club to
use a small arm of water as an experimental area for the general improvement of the re~
mainder of the lakes. This arm was separated from the main lakes by a levee. Most of
this report deals with work carried on in this small area, which will be called Sports-—
men’s Lake,

ACKNOWLEDGMENTS

The Lincoln Sand and Gravel Company is interested in further developing the
recreational uses of Lincoln Lakes and has given us unusually complete information.
The Logan County Sportsmen’s Club, and especially those members primarily interested in
fishing, have given a great deal of their time and effort in carrying out the work on
Sportsmen’s Lake. Whatever benefits may arise from this work are to a great extent the
result of their continued interest in the area, Many members have taken an active part
in the work, but we should like to mention in particular Harry A. Gehlbach, Reginald
Clark, Harold Klemm and Walter Spatz. A large part of the levee was built by the Na=
tional Youth Administration under the direction of Herman Dammerman. At the time the
census was made, we were helped by Dr. A. B. Taylor and Harry G. Kimple of the Univer-
sity of Illinois. Dr. Donald F. Hansen, of the Natural History Survey, helped through
out the census of Sportsmen’s Lake and furnished the information on the rate of growth
of the white crappies of Lincoln Lakes from his manuscript on the growth of the white
crappie in Illinois. The State Department of Conservation assisted with the work pre-
vious to the census. Louis A. Krumholz, graduate assistant of the Natural History
Survey, drew the maps and charts used in this report.

DESCRIPTION OF LINCOLN LAKES

Lincoln Lakes have a water area of 92.5 acres. (This does not include a new pond
of about 10 acres dug since 1936.) The total shoreline is 7.3 miles. The maximum
depth is reported to be 42 feet. The average depth is about 15 feet, and only 5 or 10

per cent of the water area is less than 5 feet in depth. A map of these water-filled
gravel pits is shown in fig. 8. Digging has proceeded without interruption since 1905.
The approximate dates of digging are shown on the map. The northwest water areas are

Oldest, and those of the southeast newest.

This paper is a contribution from the Section of Aquatic Biology.
3

The gravel which is being worked.was deposited in glacial times. Four to 10 feet
of topsoil must be removed to expose it. Most of the topsoil is dumped into the lakes.
The first digging was done with a dragline. In 1908, this was discarded in favor of a
steam dredge, which was operated until 1922, when electric equipment was installed.
Digging has averaged about 3 acres a year, and future operations will extend over a
period of at least 15 years. New water areas will be south of the present lakes; the
company holds land as far south as Deer Creek.

The water level in the lakes is the same as that of the ground water. Surface
drainage from about 500 acres of farm land to the north and east flows into the lakes.
Almost every year Salt Creek overflows the low land near the uam and floods Lincoln
Lakes.

The Lincoln Sand and Gravel Company has made many improvements for public recrea=-
tion on the worked-over areas. A large public bathing beach, fig. 1, was constructed
in 1930 and 1931 at a cost of $16,000. This figure does not include 300 carloads of
sand and gravel which were used. There is a large modern bathhouse and a parking area.
A small charge for swimming pays the lifeguards and other operating expenses and pro=
vides enough extra income for some new equipment each year. Figs. 2 and 3 are from
photographs taken at Lincoln Lakes.

The fees for fishing and boating are as follows:

Fishing—$1.00 per year (plus the state fishing license)
Boating--A few rowboats rent at 25 cents per hour, or $1.00 per day

Privately-owned boats may be used on the lake at the following rates:

Rownoatts 2s. ese e ewe we OO por year
Garloes* 65S s evel we. wselite) eon ener Our:
De ANTS o, Mra, |e tie mers ie ae leone ae ee 3.00 per year
MOTOR DOAESH Ss ve\cs) ee ie eae ake See ne 5.00 per year

Cottage sites may be leased for 10 years (renewable) at $35.00 per year. These
sites have a 50-foot lake frontage and are 100 feet long. Eleven cottages are now
in use.

Hunting is not allowed on this area because of the danger and the nuisance to
people seeking other recreation,

A watchman=<caretaker in the employ of the company handles the bait concession,

Picnicking and hiking are free--and skating when the company finds that the ice
is safe.

DESCRIPTION OF SPORTSMEN*S LAKE

Sportsmen’s Lake, dug in 1920 and 1921, figs. 4 and 8, is an arm of Lincoln Lakes
with an area of 3.69 acres. It was diked off in 1938 in an effort to separate it from
the other lakes and to prevent its being flooded by Salt Creek, The small lake is
shaped somewhat like a glove with six fingers, These fingers are lined with a dense
stand of small willows. The shores are wooded except on part of the west side. While
the maximum depth in open water is 194 feet, most of the channels on the east side
are less than 10 feet in depth. The average depth of the entire lake is 9.8 feet;
the shoreline is 0.8 mile; and the volume is 36 acre feet.

The levee built in 1938 was high enough to keep out ordinary floods on Salt Creek.
However, in March, 1939, Salt Creek flooded higher than at any time since 1926, and
water from Lincoln Lakes backed up into Sportsmen’s Lake, covering the levee from
March 13 to 16 and again for two days in April.

The Lincoln Sand and Gravel Company plans this summer to raise the levee high
enough to prevent all possibility of future flooding,

4

IN

SPORTSMEN'S LAKE

NEAR

LINCOLN, ILLINOIS

DEPTHS IN FEET

(&) ~ SCALE
VRS) | INCH = 100 FEET
WIRY

OYO)-

7
—

S = : f ee » e) —
SA OQ) (Cj DWE;
LW S <=

17

AREA 3.69 ACRES a
VOLUME a6 ACRE FEET
SHORELINE 0.80 MILE
FIG. 4.—Map of Sportsmen’s Lake, indicating depths in feet.

5

HISTORY OF FISH POPULATION

No written records have been kept of fish planted in Lincoln Lakes. The following
notes have been furnished from memory by sportsmen and by officials of the gravel
company. On three or four occasions since 1925, the State Department of Conservation
fish car has brought fish to the lakes. These plantings included probably largemouth
bass, yellow bass, white crappie, black crappie, warmouth bass, bluegill, green sun-
fish, yellow perch, sheepshead, channel cat, black bullhead, yellow bullhead and other
Illinois River species. Trucks have brought in fish at other times. On several oc-
casions, lake trout and wall-eyed pike fry have been planted. Fish have been stocked
probably at frequent intervals since digging was begun in 1905.

Large numbers of stream fishes from Salt Creek must have entered Lincoln Lakes
during times of flood. It is probable that all of the species of "rough" fish, the
smallmouth bass, sheepshead, gar, gizzard shad and a number of kinds of minnows and
small fishes now in Lincoln Lakes came in this way.

In July, 1937, Mr. D. John O’Donnell, at that time of the Natural History Survey,
fished for two days in what is now Sportsmen’s Lake with two 34-foot, 1-inch mesh hoop
nets. This place is not adapted to hoop—net fishing, and the water was too clear for
some kinds to enter the nets readily. His catch is listed in table l.

TABLE 1.--HOOP NET CATCH, JULY, 1937, SPORTSMEN’S LAKE
Fotal

Length,
Inches

White crappie ..

Redmouth buffalo.
Yellow bass ...
Sheepshead. . « o
Redghorse s Yeu eel
OrioslibaGk: Aigeawe ose) 6

In April, 1938, as a preliminary to the census work of the Survey, members of the
Logan County Sportsmen’s Club under the direction of Mr. Clifford Sullivan of the
State Department of Conservation fished the pond with four hoop nets in an attempt to
remove some of the fish before the water was poisoned. Several turtles were taken,
but only a few fish. Nets lifted on one day, April 29, contained one slider turtle,
Pseudemys troosti (Holbrook), and two small softshell turtles, Amyda spinifera (Le
Sueur); only one fish was taken, a white crappie, 6.1 inches long.

No bass were taken in the nets in either 19357 or 1938. However, in both years

most of the fish in the nets may have escaped through holes cut almost every night by
muskrats.

Hook-and-line fishing has been poor in Lincoln Lakes. Occasional bass have been
taken, but not more than one or two dozen each year. The Survey made a complete creel

TABLE 2.--AVERAGE TOTAL LENGTHS OF WHITE CRAPPIES OF DIFFERENT AGES

Age in Years

June 16, 1937 Total length. .
(hook-and—line catch) .] Number of fish.

May 20, 1938
(poisoned in Sports-— Total length. .
men’s Lake). . . . « «|Number of fish.

census on the opening day of the 1937 bass season, June 16. Only four legal-sized
fish were taken-—-two bass and two white crappies. Hundreds of thin white crappies
under legal length (8 inches) were caught. Scales and measurements were taken from 33
of these small crappies and their ages determined by Dr. Hansen of the Survey. In
table 2 the lengths and ages of these fish are compared with the lengths and ages
which he found among 148 white crappies obtained when Sportsmen’s Lake was poisoned,

The poor hook~and-line fishing in Lincoln Lakes is one of the reasons the Logan
County Sportsmen’s Club was given a small arm of the lakes to be diked off and used
as a hatchery pond, rearing pond or experimental area where methods could be worked

TABLE 3.--FIRST FISH KILLED BY POISON
IN SPORTSMEN’S LAKE, MAY, 1938.

Total
Length,
Inches

Largemouth bass
sub Gye Le i
Black crappie
White crappie

Green sunfish .
Yellow bass ..
Black bullhead.
Gizzard shad. .
Spotted sucker.
Golden shiner .
Brook silverside. . .
DAI EI eee es 6 ele 6 «
Miscellaneous minnows

out for the improvement of fishing in the rest of Lincoln Lakes. While the evidence
indicated that fish were scarce, it was thought desirable to clean out Sportsmen’s Lake
with poison before any fish propagation activities were begun.

FISH PREDATORS

Animals which prey upon the fishes of Lincoln Lakes are herons, cormorants, king=
fishers, gulls, fish-eating ducks, and a few turtles and gars that have migrated from
Salt Creek. It does not seem likely that these predators have noticeably affected the
fish population,

TABLE 4.——COMPARISON OF FIRST AND SECOND POISONINGS
OF SPORTSMEN’S LAKE, MAY-JUNE, 1938.

Per Cent Average Average
of Fish Weight Weight
Escaping First Second

First Poisoning, Poisoning,
Poisoning

Largemouth bass ..

Other "fine" fish*.

Baltheads: os él. «s

Bit taLOeS . 6 6 « «

Carp, quillback and suckers

Baeavard SHAGGY 4) os tee os «

Minnows and other small
EWINOU SEG CIC CE

* See table 5 for a list of "fine" fish.

Average Per Cent
Weight of
Per Fish, Total
Pounds Weight

TABLE 5.~-CENSUS OF ALL FISHES IN SPORTSMEN’S LAKE, MAY-JUNE, 1938

as yO Te ee

Qf FBR off i ee ae bs B

hH
tay)
POCO OMNNON

oO

Bluegill. .

Green sunfish .

Orange-spotted sunfish.

Wellow pereiis mw «. «a «

Vollow bass .. 6 da). aia fe

Bheepshead., «<5 fata aos @ «
TOTAL

OID ONANWAWAO

Gaara Cat. ‘fe dite See
Black bulihead. *& o. %S i e

Mongrel buffalo. .
Smallmouth buffalo.
Quillback .

Spotted sucker. .
Common sucker . .

POR D) AE ORR te vch Et

Long-nosed gar... - «= . « gels 0.6
TOTAL al 0.6

BON R) Ag Gy, Sale since Et

Straw-colored minnow.
Blunt-nosed minnow. .

picked up... mh utah
TOTAL

Total number of fish = 7,008 Number of fish per acre = 1,899
Total weight of fish = 1,256 lbs. Weight of fish per acre 340 1bs.

1938 FISH CENSUS OF SPORTSMEN'S LAKE

Sportsmen’s Lake was poisoned on May 20, 1938. The open water was treated from a
boat between 9:45 and 10:30 a.m. Between 10:30 a.m. and noon, a garden sprayer was used
to distribute poison along the edges and in the narrow channels. The fish began to
appear soon after the first poison was introduced and by noon the fish listed in table 3
had been collected, sorted and counted.

Although the poison may not have been distributed uniformly, the list in table 3
shows, in some measure, the fish that are most easily killed. The surface water
temperature was 70 degrees Fahrenheit.

It required three days to handle the fish. The procedure was the same as that
described in Lake Management Reports, 2. Fork Lake near Mount Zion, Illinois, published
by the Natural History Survey as Biological Notes No. 9, January, 1939.

When we returned to the pond on June 2, it was reported that some fish had escaped
the first poisoning. Next day we saw three fish jump. On June 14 the lake was
repoisoned with twice the original dosage, 1 pound of poison per acre foot of water.
This repoisoning was begun at 2 p.m., and before dark 7 largemouth bass and 20 redmouth
buffalo were collected. The following day, 13 bass, 7 crappies, 3 bullheads, 1 sheeps=
head, 1 quillback and 35 redmouth buffalo were picked up. These fish were large and
had evidently survived the first poisoning. Table 4 shows the percentage and sizes of
fish escaping the first poisoning. At the time of the second poisoning, large numbers
of redmouth buffalo fry and somewhat smaller numbers of largemouth bass and black bull-
head fry were killed. These fry ranged between one-half and 14 inches in length and
had been spawned since the first poisoning on May 20.

TABLE 6,.—-FREQUENCIES OF STANDARD LENGTHS OF FISHES
(EXCEPT LARGEMOUTH BASS) IN SPORTSMEN’S LAKE, MAY-JUNE, 1938.

Standard
Length,
Inches

Redmouth Mongrel Smallmouth Channel
Buffalo Buffalo Buffalo Cat

Sheepshead

“

NIPOOWrP
e

@

WNNNHHP Poe

(Continued on next page)

TABLE 6.-—-FREQUENCIES OF STANDARD LENGTHS OF FISHES
(EXCEPT LARGEMOUTH BASS) IN SPORTSMEN’S LAKE, MAY-JUNE, 1938——Continued.

Standard Golden Bullhead Blackfin Straw-colored Blunt-=nosed
Length, Inches Shiner Minnow Minnow Minnow Minnow
at 3 e@eee 4
1t ae 3A 1 6 41

eves

Gizzard Black White
Shad Bullhead Crappie Bass

Spotted
Sucker

JH» mo r0Oa~ Khe -

>
“I

Standard
Length,
Inches

Orange-
Spotted

Warmouth
Bass

* Zygonectes notatus (Refinesque)

10

The census shown in table 5 includes the fish taken in both poisonings. A large
number of individuals of all species was measured. The frequencies of standard lengths
of all species (except largemouth bass) are compiled in table 6. The carp, buffalo,
largemouth bass and channel cat were large. Most of the crappies, bluegills and other
pan fish were small, and few of them were of legal size.

The numbers and weights of hook-and-line fishes of legal sizes are summarized in
table 7. Although fishing in Lincoln Lakes is not considered good, the proportion of
legal-sized hook-and-line fish is probably rather high, since they made up 19 per cent

TABLE '7.--HOOK-AND-LINE FISH OF LEGAL SIZES.

Legal
Length,
Inches

Largemouth bass
White crappie .
BCP ee Weta te

Green sunfish
Yellow bass .
Sheepshead. «.
Channel cat...
Black bullhead.

# No legal lengths specified by state law. Arbitrary sizes chosen as the minimum for
table use.

of the weight of all fish present in Sportsmen’s Lake. It should be noted that the
_largemouth bass and the bluegill were the kinds which contributed most of the legal-
sized fish.

AGE, GROWTH AND SEX IN THE LARGEMOUTH BASS

When Sportsmen’s Lake was poisoned the first time, detailed observations were made
on each individual bass. As the number was rather large and covered a wide range of
sizes, we have treated these fish in some detail.

One hundred sixty-seven bass were taken in the two poisonings; 146 the first time
and 21 the second (not including the newly-hatched fry). Total lengths, standard
lengths and weights were taken on the first group of fish. Sex determinations were
Made, and scales collected for ages. Observations made on bass from the second poison=
ing included only the number, the total weight, 45 pounds, and the sizes of a few indi-
Vidual fish.

For many years fish investigators have used standard length measurements (tip of
Snout to end of backbone) in preference to total length measurements. Total length
asurements in inches, on the other hand, are better understood by laymen and are,
therefore, more useful in fish management.

Test measurements of standard lengths made by three workers on a single fish were
ound to vary considerably because of a difference of opinion about the exact location
of the end of the backbone. On the other hand, total length measurements varied less.
Total lengths are most uniform when measured from the tip of the snout, with the mouth
tlosed, to the tip of the tail. The tail should be extended, i.e., not spread. The
usual objection to the use of total length is that part of the tail fin may be broken
ff. However, scarcely one fish in a hundred under natural conditions shows injury to
mertail fin,

RE

Standard and total lengths were compared on all measured bass taken from Sports—
men’s Lake to learn whether the ratio of total length to standard length is constant.
The ratio was found to change as shown in table 8. It may be seen that the body grows
in length more rapidly than the tail.*

It was possible to determine the ages of all but two of the bass taken following
the first poisoning. The numbers of bass of known ages are shown diagramatically by age
groups in the shaded areas of fig. 5. The two bass of undetermined ages from the first
poisoning and 21 bass from the second poisoning were arbitrarily assigned to age groups
on the basis of size and are shown in unshaded areas in fig. 5.

Spawning and survival must have been more successful in some years than in others.
As may be expected, the greatest numbers of bass were one- and two-year-olds. But,
there were more fish in the five- and six-year groups than in the three- and four-year
groups. This fact may indicate an abundance cycle with dominant broods appearing every
three or four years. Eschmeyer** presents evidence of dominant broods among the bass

/
TABLE 8.-=RATIO OF TOTAL LENGTHS TO STANDARD .
LENGTHS IN BASS OF DIFFERENT SIZES.

' Standard Ratio of
Length, Total Length to
Inches Standard Length

which he poisoned in Howe Lake, Michigan. In his case the first summer and fourth sum-
mer fish were much more numerous than bass of other ages.

Age determinations were made from the scales, distances between ‘annuli were meas—
ured and the length of each fish at the end of each year of life was calculated in the
usual manner. Table 9 shows the average of these calculated lengths for each year’s |
spawn. Table 10 shows the average yearly length increases of the fish shown in table 9.

Curves showing the sum of the length increases and the average lengths of these
bass are given in fig. 6. The sum of the length increases (solid line) gives, in most
respects, a more nearly true picture of the growth history of these bass. Average
length curves are subject to greater irregularities. For example, the nine-year old
fish average slightly shorter than the eight-year old fish. This does not mean that
bass shrink between their eighth and ninth years but that the eight-year old average
includes two unusually large fish which are not represented in the nine-year average.

a

No significant differences in growth rates of the two sexes could be found.

:

Scales and measurements from nine largemouth bass taken by anglers from Lincoln

Lakes during 1937 and 1938 show a rate of growth similar to that of the poisoned bass
of Sportsmen’s Lake.

* Bennett found no change in the ratio of total to standard length in smallmouth bass
when the former was measured from the tip of the snout to a line across the end of
the tail spread in the natural position. Bennett, G. W. 1938. Growth of the Small-

mouth Black Bass, Micropterus dolomieu Lacépede, in Wisconsin Waters. Copeia, No.
4, pp. 157-70.

#* Eschmeyer, R. W. 1938, The Significance of Fish Population Studies in Lake Manage-
ment. Trans. Third N. Am. Wildlife Conf., pp. 458-68.

12

OF ~ FISH

NUMBER

INCHES

TOTAL LENGTH,

| 2 3 a 2S 6 FA 8 9
AGE IN YEARS

FIG. 5.--Shaded areas show numbers of largemouth bass of different
ages taken from Sportsmen’s Lake following first poisoning.
Unshaded areas represent numbers of bass arbitrarily assigned to
age groups on basis of size: 2 from first poisoning, 21 from second.

| 2 3 a 5 6 if 8 9
AGE IN YEARS

FIG. 6.--Rate of growth of largemouth bass in Sportsmen’s Lake.
Solid line, sum of length increases; broken line, average lengths.

13

| ever |

| 9s*6T_

[ user |

96°FT | LTS°ST soseelout yysueT Jo mm

Tae eseIOAY VL

Ris

FSORNMNAMN AH) ie]

NOONoODr MW

hi
1k
T.
g
T
4
0
ra

poseloay
usta JO
eJTT JO reer Iequmnn

p
ita}
ci

*@S6T ‘ANNC-AVW SOMIVI S,;NOWSLYOdS WOU NOIVL SSVA HLNOWHOUVT 0
SHHONI NI SASVHYONI HLONYI GALVINOTVO--°OT WIaVL

eseIOAY FPL

82H mks

TE
48
00
Le

peseloAy

Ustwd Jo
BIeeX UT 83 Jeqmunn

"@S6T ‘ANOP-AVW ‘SDIVI S.NWSLYOdS WOUd NODIVL SSVA HLNOWHOUT
4O SHHONI NI SHLDONYT TVLOL (&LVINOTVO--"6 WIdVL

peumeds
Jeez

14

All bass of four years and older were of legal length (i.e., 10 inches or more).
Eight out of 10 three-year-olds were of legal length, as well as 5 of the 47 two-year-
olds. The largest yearlings were 9 inches long.

Ages, length frequencies and sexual development of these 144 bass are shown in
table 11. It may be seen that sexual maturity is correlated more closely with length
than with age. All fish over 10$ inches long were sexually mature; all below 10 inches
were immature. Examination showed that males and females become mature at about the
same size.

Of the 56 sexually-mature specimens examined, 19 were females and 37 were males.

TABLE 11.--NUMBERS OF LARGEMOUTH BASS (TAKEN FROM SPORTSMEN’ S LAKE,
MAY-JUNE, 1938) OF DIFFERENT LENGTHS AND AGES, SEXUALLY MATURE AND
IMMATURE. (SEXUAL MATURITY DETERMINED BY DISSECTION. )

Total Age in Years
Length,
Inches

Sexually immature

2
3
2

wwe «

DPrH.

May 20 apparently bisected the time of annulus formation in the five younger age
groups. Sixty of these bass had newly-formed annual rings, while 66 had not formed
their 1938 rings. None of the 18 fish six or more years old had formed new rings.

’

15

These data are summarized in table 12. May 20 is about a month earlier than the mean
date determined by Hansen for annulus formation in the white crappie.#*

TABLE 12.--NUMBERS OF LARGEMOUTH BASS WITH
AND WITHOUT NEW ANNULI ON MAY 20, 1938, SPORTSMEN’S LAKE.

Number
Without New
Annulus Formed

Number With New
Amnulus Formed

il
2
3
4a
5
6
Ui
8
9

There is a tendency for the larger bass of an age group to form their annual ring
before smaller bass of the same age. This may be seen in table 13.

Some of the bass which escaped the first poisoning in Sportsmen’s Lake spawned
within the next week or two; large numbers of inch-long fry were killed by the second
poisoning, June 14. This seems to indicate a close correlation between the time of
annual ring formation and the time of spawning.

TABLE 13.--NUMBERS OF BASS OF DIFFERENT LENGTHS WITH AND
WITHOUT NEWLY-FORMED ANNULI, MAY 20, 1938, SPORTSMEN’S LAKE.

One-Year Old Bass Two-Year Old Bass

Standard
aati Ring Ring Ring Ring
Formed Not Formed Formed Not Formed

HPWAWAOA ONE -

Fish are often described as plump or thin, but investigators have devised a more
accurate method of measuring condition by dividing the weight of the fish by the cube

* Hansen, Donald F., 1937. The Date of Annual Ring Formation in the Scales of the Whi
Crappie. Trans. Am, Fish. Soc., 66:227-36.

16

of its length. It is most convenient to divide the weight in pounds by the cube of the
total length in inches. In order to avoid long decimals, the result is multiplied by
10,000; in other words, the decimal point is moved four places to the right. For ex-
ample, a 10-inch fish weighing one-half pound will have an index of condition of

oe en? or 5.0. A 20-inch fish weighing 4 pounds will have an index
of condition of pipes Tien 1OSO00 7 > or 5.0. Thus it may be seen that they are

20 hin se 20" i, x 20° in?
equally plump. This figure can be referred to as the index of condition, or abbreviated
as C.

Other workers have devised similar methods for comparing the plumpness of fish of
different sizes, but most of them have used lengths in centimeters and weights in grams;
or have used standard lengths, or some linear measurement other than total length. One
of the most common measures is calculated from standard lengths in millimeters and
weights in grams. This is called the coefficient of condition, or K. This is trouble-
some to the average fisherman because he usually measures fish in inches and weighs them
in pounds.

The index of condition, C, was calculated for each of the bass taken from Sports-—
men’s Lake which were weighed and measured. Table 14 shows that C becomes progressively
greater in longer fish. This indicates that large bass are stockier than small bass.

TABLE 14.--AVERAGE INDEX OF CONDITION, C, OF LARGEMOUTH BASS
OF DIFFERENT SIZES, SPORTSMEN’S LAKE, MAY 20, 1938,

Index of
Condition,
(S

Qn > -
OMrHNN

SHRaDA

It may be interesting in later work to use this bass population for comparison with
the bass populations of other waters. The relation of standard length to total length
has been smoothed of its minor irregularities by fitting a curve. In like manner the
relation between length and weight has been smoothed. Table 15 shows corresponding
lengths, weights and values of C and K, read or computed from these smoothed curves.

TABLE 15.--CORRESPONDING LENGTHS, WEIGHTS, INDICES OF
CONDITION (C) AND COEFFICIENTS OF CONDITION (K) OF
LARGEMOUTH BASS FROM SPORTSMEN’S LAKE, MAY 20, 1938.

Standard Weient Total Standard
Length, Ents Length,| Length,
Inches Inches Inches

OODIATP EW
BRPAASGRS
e
YNHONNNNNWND
Pea ene o Ss
.

tn iS DoH fo

e
CS SaAaesres

OPrA
Ono

t & RYE OSS
.

noon

OPP OMNMHHH
ooo) DWP O
BRANNHASS

PPP PPR RRO
DiyO PC Oo
RACHA ERA
AO

On

eoese so eS ©

Aonaannnon
e

YOVNWNWMNWNNWNWD DW
©

CRaNSSase

a
5
6
ti
8
9
10
ial
12

C1

17

LIMNOLOGICAL OBSERVATIONS
On June 2, 1938, temperatures were taken at two stations in the deeper water (Sta-
tions A and B) and at the head of one of the larger fingers (Station C) of Sportsmen’s
Lake. These temperatures are shown in table 16.

TABLE 16.--TEMPERATURES IN DEGREES FAHRENHEIT IN SPORTSMEN’S LAKE, JUNE 2, 1938.

Station A Station B Station C
Temperature Temperature Temperature

0)
1
2
3
a
5
6
7
8
9

59.5, bottom

47.5, bottom

Later in the summer, on August 12, temperatures and oxygen samples were taken at
one station in the deep, open water of Lincoln Lakes, as well as in Sportsmen’s Lake.
The first location was about 200 feet west of the boatyard. The station in Sports-
men’s Lake was the same as Station B on June 2. The temperatures and dissolved oxygen
concentrations found are shown in table 17.

TABLE 17.--TEMPERATURES IN DEGREES FAHRENHEIT AND DISSOLVED
OXYGEN CONCENTRATIONS IN PARTS PER MILLION IN SPORTSMEN’S LAKE
AND OTHER PARTS OF LINCOLN LAKES, AUGUST 12, 1938.
Lincoln Lakes Sportsmen’s Lake

Dissolved
Oxygen

PO MH O

5
6
Li
8
9
@)
it

a=)

Continued on next page)

18

TABLE 1'7.-—-TEMPERATURES IN DEGREES FAHRENHEIT AND DISSOLVED
OXYGEN CONCENTRATIONS IN PARTS PER MILLION IN SPORTSMEN’S LAKE
AND OTHER PARTS OF LINCOLN LAKES, AUGUST lé, 1938--Continued.

Lincoln Lakes Sportsmen’s Lake

Depth,
Feet Temperature Dissolved Temperature Dissolved
Oxygen Oxygen

0.0, bottom

The two series of temperatures taken in Sportsmen’s Lake, June 2 and August 12,
are diagramed in fig. 7.

The common kinds of fish found in artificial lakes in Illinois--largemouth bass,
white crappie, black crappie and bluegills--require two to three parts per million

SURFACE

4
a
ie so
ir
oo
ape
uJ
ra)
16
BOTTOM

°

TEMPERATURE, F.

FIG. 7.--Water temperatures in Sportsmen’s Lake, June 2 and
August 12, 1938.

19

of dissolved oxygen. In Lincoln Lakes, in summer, they cannot be expected to live
below a depth of 15 feet. Bullheads, however, do not require such a high concentra-
tion of oxygen as the other kinds of fish of Lincoln Lakes. Both the black bullhead
and the yellow bullhead can tolerate an oxygen concentration as low as one-half part
per million.

TABLE 18.--CHEMICAL ANALYSES OF WATER FROM SPORTSMEN’S LAKE.

April 30, 1938, Nov. 16, 1958,
Determination Parts Per Million | Parts Per Million

Iron

PaLGEmeds a. «-chtare eh Leu eure 0.08 trace

METRE! 6 ct emte olen On Oe
gitteds (SiO)... eee see 4.0 1.5
Calcium (ca) a eee, laa 49.5 37 el
Maenesivm (Me) . 26% eel 23.5 24.2
Potassium: (KS). < sci comrente 0.9 4.4
gultate (SOgye: « </fe eMel s 42.1 34.8
Nitrate (NOg). . <4 2 mits 3.2 ey,
Ghitertde: (Cie) shee ee eee 3.0 4.0
Methyl orange alkalinity. . 172.0 156 .O
Totadls hardnesist ve: veer ol re 220.5

The transparency of Sportsmen’s Lake on the day it was first poisoned (May 20,
1938) was 3 feet, as measured by a Secchi disc. Later, on June 2, after the silt roiled
by the fish had settled, the transparency was 9 feet. A heavy crop of plankton algae
had reduced the transparency on August 12 to 4 feet 3 inches. On November 16 it was
again 3 feet.

Lincoln Lakes on August 12 showed a transparency of 3 feet 9 inches,

Chemical analyses were made by Mr. J. B. Swartz of the State Water Survey on
samples of water collected from Sportsmen’s Lake on April SO and November 16, 1938.
These analyses are shown in table 18.

COARSE AQUATIC PLANTS

Lincoln Lakes support very few submerged, coarse aquatic plants. At various times
in the past, attempts have been made to establish several kinds. Some years ago the
curly-leaved potamogeton (Potamogeton ecrispus) was planted near the bathing beach. It
spread over the beach so rapidly that it became objectionable to bathers and was pulled
up. At present very little of this plant is left, and it has not caused trouble on the
bathing beach since its peak of abundance.

At the time Sportsmen’s Lake was poisoned (May 20) it contained only a very sparse,
short growth of Potamogeton foliosus in one of the larger necks of water where the
transparency was somewhat greater than in the rest of the pond.

On May 26-28, 1938, members of the Logan County Sportsmen’s Club collected a truck-
load of aquatic vegetation from some old strip mine ponds near Oakwood, Illinois, and
planted it in Sportsmen’s Lake, This load consisted of Ceratophyllum, Myriophyllum,
Ranunculus, Chara and several species of Potamogeton (including P. foliosus). Plantings
were made along the shores and in the narrow necks. An inspection on August 12 showed
that P. foliosus had "taken" the pond. It was abundant in all the necks and along the

shores, growing in as much as 5 feet of water. A few thrifty plants of Ceratophyllum
weré present near the levee.

On November 16, the Potamogeton foliosus had entirely disappeared, but some other
forms were growing more or less abundantly. Collections made in shallow water near the

20

levee at the north end of the lake included Ranunculus, Chara, Myriophyllum and Cera-
tophyllum. These latter kinds evidently came from the truckload planted in May.

RESTOCKING WITH LARGEMOUTH BASS AND BLUEGILLS

Plans for restocking were discussed with members of the Sportsmen’s Club, and it
was decided to use largemouth bass and bluegills in order to test this combination
further for high production of hook-and-line fish. (See Lake Management Reports,

2. Fork Lake near Mount Zion, Illinois, referred to previously). Plantings have been
made from a number of sources and at various times since the second poisoning on June 14.
These are listed in table 19.

TABLE 19.-—DATA ON RESTOCKING OF SPORTSMEN’S LAKE.

size
Range,
Inches

Homewood Lake. . Dept. Conservation
Homewood Lake, . Dept. Conservation
Senachwine Lake. .| Nat. Hist. Survey
Senachwine Lake. Nat. Hist. Survey

Chautauqua Lake. Dept. Conservation
Chautauqua Lake. Dept. Conservation
TalDSbs TON betas mee UicyuS 9 ee.) BSNS
Missourl: pe ue = Ute, Buia en obls
Chautauqua. Lake. Dept. Conservation
Chautauqua Lake. Dept. Conservation

Chautauqua Lake. Dept. Conservation

When planted, all of the bluegills were large enough to spawn. Approximately 20
per cent of the bass will be of spawning size in 1939. Occasional fly-fishing in the
early fall of 1958 showed that the bass planted on August 18 were growing rapidly.

Although the Sportsmen’s Lake levee was topped by the flood of March, 1939, we be-
lieve that, because the water was cold, there was little or no movement of fishes be-
tween the small experimental lake and the rest of Lincoln Lakes. During this flood
there was ice along the shores, and on the afternoon of the first day the water temper-
ature was 34 degrees Fahrenheit.

On the second flood, a month later, which is reported to have connected Sportsmen’s
Lake with the rest of Lincoln Lakes on April 16-17, we do not have such detailed in-
formation as on the first. We know that the air temperature of the Lincoln weather sta-
tion at this time was somewhat above freezing, but the probability is that the water
temperature at that time was not high enough to encourage fish movement.

We are supporting the belief that there was not much fish movement in either of
these floods by our experience at Horseshoe Lake when it was flooded for a much longer
period in January and February, 1937.* Observers reported that at the time of the Salt
Creek floods of 1939 there was no current through Sportsmen’s Lake to encourage the
movement of fishes.

The number of bass stocked in Sportsmen’s Lake is greater than the number poisoned
and will be augmented by the 1939 spawn. Unless there was more fish movement during the

* Thompson, David H., and George W. Bennett. Lake Management Reports. 1. Horseshoe
Lake near Cairo, Illinois. Illinois Natural History Survey Biological Notes No. 8.
September, 1938.

21

1939 floods than we suspect, the bass planted in Sportsmen’s Lake will be free from
competition by crappies and other carnivorous species now in Lincoln Lakes. Bluegills
offer little competition to bass and should produce an abundance of young for bass food.
Considerable numbers of young bluegills may be expected to survive the summer of 1939
and grow too large for bass to eat.

RECOMMENDATIONS FOR SPORTSMEN'S LAKE

The bass and bluegills of Sportsmen’s Lake should be fished heavily during 1939 as
well as in subsequent years. It is advisable to remove 100 or more of these bass during
1939. Any bass below legal length taken on hook and line should be carried across the
levee and placed in Lincoln Lakes. In like manner it is recommended that 150 or more of
the breeder bluegills be removed.

There should be no further stocking of the pond.

Minnows should not be used for bait because of danger of contamination of the pond
with undesirable kinds. Artificial baits, worms, grasshoppers, crayfishes, etc., are
suggested.

It is especially urged that the members of the Sportsmen’s Club keep a complete
record of the numbers and weights of fish taken from Sportsmen’s Lake. These should be
recorded in a bound record book along with notes on transparency of the water, sub-—-
merged vegetation, waterfowl, fish predators, dead fish, etc. The equipment for making
these observations and the record book should be kept in a locked box set up near the
levee. A supply of scale envelopes should be included for the collection of scales and
measurements useful in following the growth of the fish. A gage board should be attache
to a substantial post or piling near the box. Keys to the box should be carried by
those members of the club most interested in fishing, A rough table nearby would be a
convenient place to clean fish and to make observations on then.

The levee should be built higher than any possible floods on Salt Creek. The in-
stallation of a frame with rollers would provide a convenient method for transferring
light boats back and forth between Sportsmen’s Lake and other parts of Lincoln Lakes.
The levee should be planted with Lespedeza or other low, soil-binding plants which pre-
vent erosion. No further erosion control or planting seems necessary around Sports—
men’s Lake. No further aquatic plantings seem necessary until the results of last
year’s planting are learned.

RECOMMENDATIONS FOR LINCOLN LAKES

Since the water supply of Lincoln Lakes is ground water, except for surface drain-
age from about 500 acres of farm land and overflow from floods on Salt Creek, it seems
advisable to build levees to keep out flood waters from the creek, as these waters make
the lake turbid and bring in undesirable fish. It is probable that the high fish produc-
tion in Lincoln Lakes may be maintained through drainage from the surrounding farm land.

If larger amounts of submerged aquatic vegetation seem desirable, they may be
transplanted from Sportsmen’s Lake after they have been tested there.

Much better bass fishing than in recent years seems possible, and more successful
methods for taking these bass on hook and line should be sought. Since Lincoln Lakes
are unusually deep and relatively free of organic matter, satisfactory amounts of
oxygen are present in midsummer at depths as great as 15 feet. This condition suggests
that the bass may spend most of their time in deep water. Lincoln Lakes are crowded
with large numbers of small, stunted white crappies. White crappies of legal size
should be removed as rapidly as possible in order to promote more rapid growth among
those remaining and to reduce their competition with the bass.

A few dozen nest boxes erected at suitable places around Lincoln Lakes may promote
the establishment of wood ducks in the area.

22

SUMMARY

1. Lincoln Lakes are water-filled excavations made by the Lincoln Sand and Gravel
Sompany since 1905. This company has developed these water areas in many ways for
public recreation.

2. These lakes now have a water area of about 100 acres, about half of the total
vater area of Logan County.

3. The company, in 1958, turned over a small area of water-to the Logan County
jportsmen’s Club to be used for the improvement of fishing in Lincoln Lakes. This area
1as been separated from the other lakes by a levee and is called Sportsmen’s Lake.

4, After unsuccessful attempts to remove the fish of Sportsmen’s Lake with nets,
it was poisoned on May <0, 1958. A few large buffalo, bullheads and bass survived this
Pirst poisoning, and it was repoisoned on June 14; twice the original dosage was used.

5. A complete fish census was made which included at least 29 species. A total
of 7,008 fish weighed 1,256 pounds, the per acre equivalent of 1,899 fish weighing 340
ounds. About 19 per cent of the total, or 239.4 pounds, were hook~and-line fish of
legal or edible sizes.

6. The white crappies of Lincoln Lakes, although numerous, are small; age de-
perminations showed that they have grown very slowly.

7. A comparison of standard and total lengths on 146 largemouth bass showed that
che body of the fish grows in length more rapidly than the tail.

8. The growth histories of these bass were read from their scales and their
lengths calculated for each year of life. All bass four years of age and older were
\f legal length. Eight out of 10 three-year-olds were of legal length, as well as 5 of
17 two-year-olds.

9. Evidence was found that dominant broods of bass occur at intervals of three or
Pour years. It appears that bass between one and seven years of age die at the rate of
about 25 per cent per year, while older bass die at the rate of about 50 per cent per
rear..

10. Sexual maturity in bass was found to be related more closely to size than to
ze. Both males and females become sexually mature when they reach total lengths of
lO to 104 inches, regardless of age.

11. About one-half of all the bass under five years of age had, on May 20, 1938,
lew annual rings on their scales. None of the older fish had 1938 rings. There is a
tendency for the large fish of an age group to form annual rings before the smaller
fish of the same age.

12. A method was devised for measuring condition, or plumpness, by use of total
length in inches and weight in pounds.

13. Transparencies, temperatures and chemical characteristics of the water for
1938 were determined.

14. Indigenous, coarse aquatic plants increased after the fish were poisoned and
the water had cleared. Other kinds were planted with some success.

15. Sportsmen’s Lake was restocked with largemouth bass*° and bluegills.
16. Suggestions for the improvement and management of Sportsmen’s Lake and

Lincoln Lakes during the next few years were outlined.

23

—-

a

‘snp e10M SONeT 949 YOTYM UO Sogep eqeUTxXoIdde oyy BuTMOYUs ‘seyey] ULOOUTT Jo deW--"g “yIW

So
t

JE ee aS Re
aiva - L€6! @

AINV1d TaAVed

-—-_~-—
4

SE Pee eae
Bis ; 2 :

1-026!

41334 00S
a cr

319s

S39VL109 ©

SPIN €2Z 3NIMT3YOHS
S3Yuov S26 VW3"V

226!

Weg
aN “OYVALVOS

N
SIONIT1 “NIOSNIT

S3Y¥V1 NTIOONT 3

ie ~
; , \ i ° Whe
RRA 4 INTOONIT. OL ; :

pas

QY’ & HOV3a ©
™ ONIHLVE

ee Pa

Sree

Seb Se be a ht

nA 2 : eS
ret ase re : Seo
Stee oe SRE
¢ e 5 : rte ges ee > : . . ; gies
se : Bore Dtecrw eer
" GE BEE ES ees NARA
ee ne See ee Ee od
es ae

<e
eT
6 ENS

ecw

a
Renae.
rs .