Distributional Ecology of the Cisco (Coregonus artedii)
in Indiana'
DAVID G. FREY
Indiana University
ABSTRACT
The cisco is known with considerable certainty to occur in 41 lakes of northern
Indiana, of which Shriner Lake at a latitude of 41° 14' N. is the southernmost known
natural occurrence of the family Coregonidae. There are three and possibly more instances where lakes with cisco populations several decades ago no longer contain the
species, presumably as a result of altered limnological conditions. The few recorded
attempts at stocking the cisco in lakes in which they did not otherwise occur have
apparently been quite uniformly unsuccessful, and it is concluded that the preColumbian distribution has not been extended by man's activities.
•
The species generally occurs in the deep water of a lake in summer. As oxygen
conditions become progressively more severe, the population is forced into the upper
part of the hypolimnion, and finally into the lower or even the upper part of the
thermocline. It is assumed in this paper that the species can tolerate water temperatures as high as 20° C., and an oxygen content as low as 3 ppm., or possibly even slightly
lower. As the species is forced progressively higher in the lake it comes into increasingly greater content with species of fish commonly occurring in the epilimnion, and
may even be preyed upon by the bowfin and the northern pike.
The summer bathymetric distribution of the species in several Indiana lakes was
determined by means of gill nets, and in the other lakes it was inferred from the extremes of temperature-oxygen stratification of summer. Data available for 37 cisco
lakes as compared with 53 non-cisco lakes demonstrate that in general the cisco lakes
have a thicker stratum of water with temperatures below 20° and an oxygen content
greater than 3 ppm. The shallower cisco lakes tend to have an oxygen maximum in
the thermocline, and in one lake such a photosynthetic maximum has occurred regularly
over four successive summers. This type of oxygen distribution is believed significant
in enabling the species to survive in small and shallow lakes.
The facts that the cisco lakes in Indiana occur in definite clusters and that these
lakes tend to have a different type of oxygen distribution than the non-cisco lakes
point to the importance of regional geologic and geomorphic controls in the limnology
of the lakes and consequently in the persistence of cisco populations in them.
Contribution No. 585 from the Department of Zoology, Indiana University. The
field studies reported on here were financed largely by the Indiana Department of Conservation. The assistance of the following temporary employees of the Indiana Lake
and Stream Survey is gratefully acknowledged: Edwin B. Davidoff, Christopher Davis,
William R. Eberly, Allan E. Johnson, Harold R. McReynolds, George Naryshkin, Russell
Noyes, Jr., William D. Ploughe, Thomas W. Pape, William H. Schleicher, Keith V. Slack,
Tom A. Stombaugh, and Richard B. Williams.
INVEST. INDIANA LAKES & STREAMS VOL. IV, No. 7. OCTOBER 1955.
177
178
TABLE OF CONTENTS
Page
Introduction ............................................................................................................................................... 178
Distribution of the cisco in Indiana ............................................................................................... 180
Indiana cisco chronology ............................................................................................................ 180
Additional records of ciscoes in Indiana ............................................................................ 183
Distribution of cisco lakes by major drainages ................................................................. 186
188
Artificial stocking of ciscoes
Factors governing the summer bathymetric distribution ...................................................... 191
Influence of age on oxygen-temperature requirements ........................................................ 196
Summer bathymetric distribution in Indiana lakes ............................................................... 198
A. Indian Village chain of lakes (Noble Co.) ................................................................... 199
( A) 1. Indian Village Lake ...................................................................................................... 199
(A) 2. Hindman Lake ................................................................................................................ 201
(A) 3. Gordy Lake ....................................................................................................................... 201
(A) 4. Knapp Lake ....................................................................................................................... 201
202
5. Tippecanoe Lake (Kosciusko Co.)
6. Oliver Lake (LaGrange Co.) .................................................................................... 203
7. Myers Lake (Marshall Co.) ...................................................................................... 203
Comparison of temperature and oxygen stratification in lakes with and without
ciscoes
207
Types of oxygen distribution in cisco and non-cisco lakes .................................................. 212
Constancy of oxygen typology during given summer .................................................... 212
Oliver Lake ............................................................................................................................. 212
Myers Lake ............................................................................................................................. 213
Little Tippecanoe Lake ...................................................................................................... 215
James Lake ............................................................................................................................. 217
Oxygen type-frequency distribution ...................................................................................... 217
Relation of oxygen typology to summer surfacing and mortality
221
Discussion and conclusions ................................................................................................................ 222
Literature cited ........................................................................................................................................ 225
INTRODUCTION
The coregonid fishes, which are closely allied to the trouts and sometimes are included in the same family with them, occur widely distributed
in the lake districts of the northern portions of both North America and
Eurasia. Except for its absence from Greenland, the group is continuously circum-boreal in distribution. The southernmost latitudinal limit
of the natural distribution of the family is reached in the lake district of
northern Indiana (Meek 1916:136) and in fact, the southernmost known
natural occurrence of the family is in Shriner Lake in Whitley County,
Indiana, at a latitude of 41° 14' N. The various types of coregonids are
so plastic in their phenotypic expression that almost every lake has its
own particular race, nation or subspecies of the species concerned.
The most widely distributed coregonid in the glacial lakes of the
northern United States and Canada is the cisco, Core gonus artedii
Le Sueur. This species extends through the glaciated portion of the
United States at least from New York to Minnesota, and in Canada it
extends northward to Hudson Bay and environs (Dymond 1933) and
northwestward into the Yukon and Northwest Territories (Dymond
1943). This is a pelagic, plankton-feeding species with a terminal mouth,
179
belonging to the subgenus Argyrosomus of the European terminology.
Like the other members of the genus it has been considered to be a cold
stenotherm requiring a fairly high level of dissolved oxygen, although its
oxygen requirement is apparently less demanding than in the whitefishes.
The present study, however, demonstrates that local cisco populations can
be much more tolerant of high temperatures and low concentrations of
oxygen than is commonly assumed.
The phenotypic plasticity of the cisco is demonstrated by the fact that
Koelz (1931) recognized 24 groups (subspecies) within this one species,
although Hile (1936b and 1937) later concluded that there was insufficient basis for establishing these infra-species categories. Moreover, as
Hile pointed out, there is a considerable environmental control of phenotypic expression, so that, for example, different year classes within a
single body of water are able to differ significantly from one another in
various morphometric characters.
The present study is concerned particularly with the distribution of
the cisco, and the factors controlling its distribution. If we assume for
North America, as Thienemann (1950) has done for several of the coregonids in northern Europe, that in late-glacial, or at least by early postglacial, time all the glacial lakes (including ice-block basins without outlets?) in the appropriate watersheds contained ciscoes, then the absence
of the cisco from particular lakes must have resulted from the development of conditions unsuitable for the continued survival of the species.
Thienemann (1918) concluded for Coregonus maraena in northern Germany that the species was eliminated from certain of these lakes as the
oxygen content of the hypolimnion declined to certain minimum values,
accompanying the natural typological aging of the lakes. Willer (1924)
reached similar conclusions regarding Coregonus albula in East Prussia.
A few lakes which did not naturally have coregonids now have vigorous populations of various species established through artificial stocking. This is true of all the large, deep lakes along the southern slope of
the Alps, and also of a very few lakes in northern Germany. The great
bulk of the attempted plantings in this latter region, however, were
unsuccessful. The ability of these fishes to survive and maintain their
populations in a lake, particularly in one in which the epilimnion reaches
temperatures too high for the various species, is regarded as an indication
of the presence of adequate levels of dissolved oxygen in the hypolimnion
throughout the summer. Indeed, in northern Germany the lakes containing the whitefish-type coregonids (particularly Coregonus maraena) belong to the early stages of the profundal midge succession. Coregonus
maraena and Tendipes plumosus are mutually exclusive. On the other
hand, Coregonus albula, which is very closely related to our cisco in morphology and physiology, apparently reaches its maximum abundance during the mesotrophic stage of lake development (Willer 1924).
So far as known, Indiana does not have more than one or two lakes in
which the hypolimnial oxygen levels remain fairly high throughout the
180
summer, at least consistently so from one year to another. Usually there
is a very marked depletion. Yet the cisco in Indiana is known to occur
in lakes having a surface area as small as 2 ha., or a maximum depth as
small as 6 m. Such morphometry must certainly provide environmental
conditions near the survival limit for the species. Because of the great
limnological interest in the factors controlling the distribution of the
various species of coregonids, it was decided to initiate a study on the
particular species occurring in the inland lakes of Indiana.
DISTRIBUTION OF THE CISCO IN INDIANA
Reference to the cisco of Indiana has been in the literature since 1875
when Jordan described the population occurring in Tippecanoe Lake as a
separate species, Argyrosomus sisco. Subsequent references have listed
additional lakes in which the species occurred, described the growth rates
of particular populations, or discussed the synonymy. Koelz (1931) listed
the Indiana cisco as subspecies sisco of Leucichthys artedi, characterized
by a relatively short head, snout, maxillary, and paired fins. However,
the number of specimens from Indiana lakes available to him for examination was so small that definitive conclusions could not be reached.
An annotated listing of the Indiana cisco chronology follows below. The
complete literature citations are given in the bibliography.
Indiana Cisco Chronology
1875a. Jordan. Specimens from Tippecanoe Lake collected about Nov.
25, 1875, were described as a new species, Argyrosomus sisco,
thought to be distinct from the related species in Lake Michigan.
Reported to occur also in nearby Barber Lake (now known as the
Barbee Chain), although not known to occur elsewhere in Indiana.
Apparently identical with the cisco of southern Wisconsin, known to
occur in lakes Geneva and Mendota.
1875b. Jordan. Same material as in Jordan 1875 a. No new records.
1875c. Jordan. Mentions Argyrosomus sisco as one of four species occurring in the State (the other three only in Lake Michigan).
1876. Levette. Argyrosomus sisco "abounds" in all the lakes tributary
to the Tippecanoe River. Also occurs in great numbers in Lake
James (Steuben Co.), where large numbers are caught annually during the spawning period.
1877. Jordan. Fifteen specimens listed from Region V, comprising Lake
Manitou in Fulton Co., and lakes Center and Tippecanoe in Kosciusko Co. No closer locality information is given. An attempt to
locate these specimens in various museum collections was unsuccessful. Possibly the specimens were destroyed during the disastrous
fire in Owen Hall at Indiana University in 1883. This citation is
the earliest known reference to the possible occurrence of ciscoes
in Manitou Lake. Blatchley and Ashley (1901) definitely list the
cisco from this lake on the authority of a Dr. Vernon Gould. Gerking
181
(1945) erroneously ascribed the latter record to Eigenmann and
Beeson (1894). It is not too likely that the specimens concerned
came from this lake, and it is certain that none of the specimens
came from Center Lake, because of the extreme summer oxygen
depletion in this body of water. Most probably the specimens came
from Tippecanoe.
1878. Jordan. Core gonus artedi var. sisco listed as occurring in "Lake
Tippecanoe, etc."
1886. Jordan and Everman. List the cisco as occurring "in the deep
lakes of Northern Indiana (Tippecanoe, Eagle [ = Winona], Maxinkuckee, etc.) . . ." This reference to the presence of ciscoes in
Winona and Maxinkuckee is surprising coming from Jordan and
Evermann, because there is no tangible evidence that the species
has occurred in these two lakes in modern time.
1887. McDonald. Quotes a letter from F. M. Baker of Rome City, Indiana, that ciscoes occur "in some of our lakes in Kosciusko and
Noble Counties." This is the first reference to the occurrence of
the cisco in Noble County. Although the lakes are not specified, it
is likely that the Indian Village group is being referred to.
1892. Jordan. This paper is identical with Jordan (1875b), except that
the figure is omitted.
1894b. Kirsch. Three specimens from Shriner Lake in Whitley Co. Reported to be common in nearby Cedar Lake, but not present in nearby Round Lake or in Blue Lake three miles to the east. Common in
nearby Crooked Lake, and present in small numbers in the west end
of Big Lake ( Noble Co.). These two latter lakes are at the head of
the Tippecanoe Drainage, just over the divide from Cedar, Shriner,
and Round Lakes, which are collectively known as Tri Lakes.
1894. Eigenmann and Beeson. List the records cited by Kirsch. Also
quote a paper ascribed to Jordan in 1877, reporting ciscoes as occurring in lakes Eagle [= Winona] and Maxinkuckee, but in the
supposedly complete bibliography of Indiana fishes in this same
volume there is no paper by Jordan containing these references.
The only known reference to the occurrence of ciscoes in these two
lakes is that by Jordan and Evermann (1886).
1895. Kirsch. Cisco not listed from any lakes of the Maumee Drainage,
except Lake Erie. Fish Lake [-= Hamilton Lake] in Steuben Co.
and lakes Indian and Cedar in Dekalb Co. are specifically mentioned.
1896b. Kirsch. More or less repeats information contained in Kirsch
(1894b). Emphasizes that ciscoes do not occur in Round Lake.
Ciscoes in Cedar Lake reported to be smaller than in Shriner Lake.
1896. Evermann and Smith. Ciscoes reported as occurring only in Tippecanoe, Crooked, Shriner, and Cedar Lakes in Indiana. Measurements are given on four specimens from Crooked Lake ( Whitley
Co.).
182
1901. Blatchley and Ashley. List cisco as occurring in Blue River Lake
[ , Blue Lake] in Whitley Co. on the basis of a collection made by
Kirsch in 1892, even though Kirsch (1894) definitely states that the
cisco does not occur in Blue Lake. This is undoubtedly an erroneous
reference. Other valid records by Kirsch for lakes in Whitley and
Noble counties are cited. The cisco is also listed as occurring in
Lake Manitou (Fulton Co.) on the authority of a Dr. Vernon Gould.
Another list cited here of 19 species collected in the lake by Eigenmann and Norman does not contain the cisco, and in light of other
known instances of Blatchley's uncritical and sometimes erroneous
references to the literature, the record for Manitou must be regarded with considerable suspicion.
1902. Blatchley. Repeats the list of 19 spp. of fishes "known" to occur
in Blue River Lake as cited in the 1901 paper by Blatchley and
Ashley.
1902. Hay. In Indiana, the cisco is listed as occurring in the Tippecanoe
River and its tributary lakes, and in lakes of the Eel River system.
1908. Meek. Cisco merely reported to occur in lakes of northern Indiana
and southern Wisconsin, without any specific localities being mentioned.
1911. Jordan and Evermann. Cisco known to occur in lakes Tippecanoe,
Barber, Crooked, Shriner, Twin, Cedar, and James. It is not certain
whether the Twin Lakes listed is the group in Marshall Co. or in
LaGrange Co., although the latter is more likely. Three specimens
from James Lake (Steuben Co.) collected by W. S. Blatchley are
recorded.
1913. Lower. This is one of the most significant studies on the cisco of
Indiana. Lower lists the species as occurring in Tippecanoe, Barbee,
Crooked, Shriner, Twin Lakes, James, Dallas, Royer, Long, Lake of
the Woods, and Little Balls (location ?). Has two photographs of
three specimens from Lake of the Woods. Gives measurements on
specimens from Lake of the Woods, McLish, and Royer Lakes.
Describes late summer mortality of the cisco in Long Lake.
1915b. Miles. Several ciscoes planted in Crooked Lake (Steuben Co.),
but none known to have been subsequently seen or caught.
1920. Evermann and Clark. Attempted unsuccessfully to locate ciscoes
in Maxinkuckee with gill nets in July of 1899. Concluded the species was not present.
1931. Hile. Caught 62 ciscoes in Indian Village Lake, 24 in Gordy, and
11 in Hindman, all of which are small lakes in the Indian Village
chain in southwestern Noble Co. Hile studied the age and growth
of these populations.
1931. Scott. Reports ciscoes from lakes Snow, James, Indian Village,
and Tippecanoe. Discusses the relation of the oxygen notch in the
thermocline to the surfacing of ciscoes in Snow and James lakes
in September.
183
1931. Koelz. Examined four specimens from Gordy Lake, three from
Indian Village, one from James, and two from Tippecanoe. Classified them as subspecies si,sco of Leucichthys artedi, although the
small number of specimens prevented a final decision on the matter.
They seemed to be closer to subsp. artedi.
1938. Blatchley. Lists the species as occurring only in Tippecanoe,
Shriner, and Cedar lakes, and in the Tippecanoe River. Obviously
he had not searched the literature very thoroughly.
1945. Gerking. Reports ciscoes in the Twin Lake group (Lawrence and
Myers lakes) in Marshall Co. and in Clear and Gage lakes (Steuben
Co.), in addition to records already in the literature. The occurrence of the species in Lake Manitou is erroneously ascribed to
Eigenmann and Beeson (1894), and in Oswego Lake to Jordan
1875b).
TABLE
1. Known and reported occurrences of the cisco in Indiana lakes through 1945.
The original source of each record is listed.
Lake
I. Based on actual specimens:
Tippecanoe
Shriner
Crooked
James
Royer
Lake of the Woods
McLish
Indian Village
Gordy
Hindman
II. Reported to occur:
Barber [= Barbee]
James
Eagle [= Winona]
Maxinkuckee
Cedar
Crooked
Big
Manitou
Twin
Dallas
Long
Little Balls
Snow
Lawrence & Myers
Clear
Gage
III. Questionable reports:
Blue River [= Blue]
Crooked
Oswego
County
Source
Kosciusko
Whitley
Jordan 1875a
Kirsch 1894
Evermann and Smith 1896
Jordan and Evermann 1911
Lower 1913
Pl
Steuben
LaGrange
PP
Steuben
Noble
Kosciusko
Steuben
Kosciusko
Marshall
Whitley
>,
Noble
Fulton
LaGrange ?
LaGrange
Nile 1931
Jordan 1875a
Levette 1875
Jordan and Evermann 1886
Kirsch 1894
Blatchley and Ashley 1901
Jordan and Evermann 1911
Lower 1913
21
Steuben
Marshall
Steuben
Scott 1931
Gerking 1945
PI
Whitley
Steuben
Kosciusko
Blatchley 1902
Miles 1915
Gerking 1945 (erroneously
citing Jordan 1875b)
184
Table 1 summarizes the distribution of the cisco in Indiana lakes, as
reported in the literature through 1945. Specimens of fish from ten
lakes were examined by competent persons and reported in the literature.
The species was reported to occur in 14 additional lakes, excluding the
"Twin Lake" listed by Jordan and Evermann (1911), since the exact
identity of this lake is not known, although it is believed to be the group
in LaGrange Co. In addition, there are questionable or definitely erroneous reports of ciscoes occurring in three other lakes.
Additional Records of Ciscoes in Indiana
Since 1937 it has been lawful to fish for cisco with nets in Indiana
lakes during the period November 1 through December 31, both dates inclusive. Upon payment of a license fee of $2 annually, each person is permitted to fish one gill net not more than 150 feet long, with an extension
measure of not less than 21/2 inches. It is illegal to fish with the bottom
of the net more than 15 feet below the surface of the water. All nets must
be surrendered to the Conservation Department for storage during the
closed season. Each fisherman is supposed "to strip or otherwise remove
the milt and spawn from each cisco, as it is taken from the net, and to
return such milt or spawn to the waters from which the cisco was taken."
There is no direction that the eggs and sperm be mixed together before
being placed in the water !
The laws governing the catching of cisco in the inland waters of
Indiana have been changed drastically a number of times. In 1875, when
Jordan described the population from Tippecanoe, there were no fish
laws, and people caught ciscoes in shallow water during spawning season
in a variety of ways. The Office of State Commissioner of Fish (later,
Fisheries and Game) was established in 1881. Soon thereafter the
first fish laws were enacted, including one permitting the taking of ciscoes by net or spear during a certain specified period in November and
December, the limits of which were changed by various commissioners.
In 1901 a closed season for all fishes from December 1 to April 1 was
established, and the use of nets and spears at any time of the year was
abolished. This closed season was in effect until the present law was
enacted in 1937.
In 1951 there were 129 persons licensed to fish for cisco in Indiana in
the manner prescribed above. A questionnaire soliciting information on
the occurrence, abundance, annual catches, and spawning behavior of the
cisco was sent to all these persons. Replies were received from 44, distributed quite satisfactorily over the entire lake district.
According to these returns, cisco are definitely fished for in 29 lakes,
and are reported to occur in an additional 12 lakes. The data are summarized in Table 2, with each fisherman concerned being listed by his
license number. The distribution of these lakes is shown in Figure 1.
It is immediately apparent from the table that cisco fishing is largely
a local cultural activity. A fisherman not only tends to concentrate his
efforts in the lakes close to his place of residence, but also shows little
TABLE 2. Summary of questionnaire to cisco fishermen as to which lakes contain ciscoes. The post office address and 1951-license number
of each fisherman is given. Symbols: X = ciscoes actively fished; R = ciscoes reported to be present but not fished.
m
Ray
Hudson
Fremont
Angola
122
219
175
141
233
163
164
150
223
209
217
208
193
R
X
X
X
R
X
X
X
XXXXXX
X
X
R
R
XRR
X XRX XX
RR
XX XX X
XRXXRR
XRRR
X X XXX X
X
XRXRXR
Secrist
N
Shock
.''
u
Oswego
"..
,..
Kosciusko
Whitley
BigTippecanoe
0
Noble
Vii
14
''. E
iteuben '
.
0
`g
-5
z
g 0
.= .
Q g g, --5 .r. E — -" - > • —
:4 4 4' :'. c4 5 ,i
r c, c.5 CC
.4
o.
]ounty
Post Office
Location of
Cisco
Fishermen
Little Tippecanoe
—
LaGrange
Steuben
R
It XRRR
XX
R XRRR
.
R
It
X
LaGrange
LaGrange
384
RRX
Noble
Albion
R
XX
X
X
R
X
X
South Whitley
Marshall
Argos
159
X X
St. Joseph
Mishawaka
South Bend
154
111
153
X
X X
X
Kosciusko
Leesburg
199
192
106
198
126
107
127
128
129
Kimmel
Wolcottville
Ligonier
Columbia City
Larwill
North Webster
X
XXX
X
X
R
X
136
224
201
112
125
115
227
190
147
137
225
113
188
134
133
114
109
X
X
X X XR XR X
XRXR
X
X
RR EL
R
R
X
X XX
X X?
X
X ? X
X XRR
R
X
R 11
R
X
X
X
X
XR
XX
(Fishing club—no ciscoes)
X
XX
X
X
XX
X
X
R
XX
X
R
X
X
X
XRR
X
XX
XXR
X
X
X
X
X
R
X
X
X
185
knowledge as to the occurrence of ciscoes in lakes outside his own particular region. This limited knowledge of cisco distribution among the fishermen makes it probable that there may be additional lakes containing small
populations of ciscoes. However, because of the relation between chemical
stratification of the water and the presence of ciscoes to be discussed
later, it is doubted that any lakes actively fished are omitted.
Only five lakes listed are fished by just one person, but in two of
these ciscoes are reported by other persons as being present. This may
be another example of the very local nature of the knowledge concerning
cisco lakes, and it may also indicate that the fish population in a lake
must be at least a certain minimum level to make it worth the effort
necessary to catch the fish. On the other hand, for eight lakes the occurrence in them of non-fished populations is reported by single fishermen.
The list of 41 lakes includes 19 of the 25 lakes previously reported in
the literature as containing ciscoes. Hence, the number of known and
reported cisco lakes has been doubled by the present study. It might be
well to point out here that ciscoes have been caught in lakes Tippecanoe,
Myers, Knapp, Indian Village, Gordy, Hindman, Oliver, and Cedar (Whitley Co.) by Lake and Stream Survey crews in 1951 and 1952 (Table 4).
This increases to 14 the number of lakes in which the occurrence of ciscoes is substantiated by actual specimens.
Regarding the six lakes (Big, Winona, Maxinkuckee, Manitou, Twin,
Little Balls) reported in the literature to have cisco populations but not
listed by the cisco fishermen, the identities of the Twin Lakes reported by
Jordan and Evermann (1911) and of Little Balls Lake reported by Lower
(1913) are not known. Since, however, the two groups of lakes in Marshall and LaGrange counties known as "Twin Lakes" both contain ciscoes,
the exact identity is not needed in this instance except for historical
chronology. As already stated in the cisco chronology, there is no tangible evidence, contrary to the report by Jordan and Evermann (1886),
that the cisco has ever occurred in modern time in lakes Maxinkuckee
and Winona.
Not one of the 11 persons reporting being active in the Tri LakesCrooked Lake region listed the species as occurring in Big Lake (Noble
Co.), so that it is entirely possible the cisco has died out in this lake in
the past 60 years. Likewise, if the report by Blatchley and Ashley (1901)
of the former occurrence of the cisco in Manitou Lake is correct, then
here too the species may have died out within the past 50 years. The cisco
has also been reported by Mr. Lowell C. Reinhart, an old time cisco fisherman from Hudson, Indiana, to have occurred many years ago in Big
Long and Turkey Lakes in Steuben Co., but the populations have apparently died out. For a species such as the cisco tending to be restricted to
youthful or middle age lakes, typologically speaking, one would expect the
number of suitable localities to become progressively smaller with time.
Thienemann (1918 and 1928) has already pointed out several instances
where north German lakes formerly containing populations of Core gonus
186
maraenus or C. lavaretus no longer have these fishes because of changes
in the limnological conditions affecting the ecology of the species.
The fish populations in the various lakes do not all have the same
characteristics. According to the fishermen, where the populations are
small the individual fish tend to be large, as in the Indian Village lakes.
Conversely, where the populations are large, as in Myers and Oliver lakes,
the individual fish (known locally as "spikes") tend to be small. To a
certain extent, the population in a given lake is said to retain its sizeabundance characteristics from one year to another, but a number of
experienced fishermen also reported that there are quasi-cyclical fluctuations in size and abundance in individual lakes : when the fish are abundant they are small, and when they are less abundant they are larger in
size. Hile (1936a) found this relationship to hold true among the cisco
populations of four lakes in northeastern Wisconsin, noting that the
occurrence of dominant year classes depended on purely local conditions
affecting spawning and survival, and Jarvi (1950) has been observing
similar fluctuations in the coregonid populations in Finnish lakes for
many years.
This variation in size and abundance from lake to lake and from year
to year within a lake may account for some of the lakes reported as having the species present but not fished. Certainly, a 2%-in. (extension
measure) gill net would not adequately sample some of these populations.
In fact, a number of fishermen contrary to the law as written (but not
necessarily contrary to the sound management of the species) somehow
manage to have a variety of gill nets available : the particular one used
in a given lake in any year depends upon the average size of the fish in
that year.
Distribution of Cisco Lakes by Major Drainages
The Lake District of Indiana, shown in Figure 1, lies largely within
the Erie-Saginaw Interlobate Moraine, also known as the Packerton
Moraine, extending in a general southwest-northeast direction for a distance of 100 miles to the northeast corner of the State and into southern
Michigan. The moraine is of complex origin, dating from Cary Time
within the Wisconsin Glacial. In present time, all the major drainages
in the northern part of the state originate in lakes in this moraine.
Earlier drainage relationships and changes in drainage during and immediately after Cary Time unfortunately are only very imperfectly
known, which complicates the task of explaining the present distribution
of cisco lakes.
Cisco lakes occur in all the major drainages arising in the Packerton
Moraine, both those entering the Great Lakes and those ultimately entering the Mississippi River (Table 3). The Kankakee River, which unites
with the Des Plaines River in Illinois to form the Illinois River, and this
in turn joins the Mississippi just north of St. Louis, has two cisco lakes.
The Tippecanoe Basin contains five lakes with ciscoes, and the Eel River
CISCO LAKES OF INDIANA
A
1
21
CLEAR
ATWOOD
31
HINDMAN
2 GREEN
22 WH 1 TMER
32
GORDY
3 MARSH
23 SLOAN
33
I NDIAN
4 YOUNGS
24 FISH
34
SHOCK
35
SECRIST
5 NORTH
OT TER
25 SOUTH
TWIN
•
q.
—110
25
c'11
8
26 ROUND
36
LITTLE
27 SHRINER
37
TIPPECANOE
8 JAMES
28 CEDAR
38
OSWEGO
9 JIMERSON
29 CROOKED
39
LAWRENCE
30 KNAPP
40
MYERS
10
TIPPECANOE
46
ST JOSEPH
RIVER
24
OHIO
23
GOOSENECK
41
17
1 2 Mc LISH
19
1 3 LAKE OF THE WOODS
1 4 BIG LONG
18
,1
6
1 5 EVE
16 MARTIN
A
-
1 7 OLIVER
M-ARS-HAL- L
42
H
STEUBEN
14
0
22
LAGRANGE
18 HACKENBERG
11
• • ■■•
■■•■• • 111■4
,
7
vt
7 KRIELBAUM
II
• • 01■1,
•
VILLAGE
6 SNOW
1 0 GAGE
MICHIGAN
4I•
;
45
,
MAUMEE RIVER
BASIN
19 MESS1 CK
ELKHART
4•
20 DALLAS
j
34
•
-38
KANKAKEE
RIVER
/
--
37-'
36
a
40
•
33
32 31
_ 30
•
"
35
39
,
29
4,
4
• \_,,,1
NOBLE
'
27
26
0.
•
FORMER CISCO LAKES
STARKE
•
41
TURKEY
42
LONG
43 BIG
44 MANITOU
411,
TIPPECANOE
,
R/ VER
KOSCIUSKO
44
CISCOES
L_
-
1\
wHITLEy
j
45 HAMILTON, in 1947
46
\
EEL RIVER
FULTON
„
FIG. 1.
Distribution of
cisco lakes in Indiana.
PLANTED
CROOKED, ca. 1915
187
TABLE 3. Distribution of cisco lakes by county and river system. Questionable reports
and lakes formerly having cisco populations are in parentheses.
River system
County
Kankakee Tippecanoe
Eel
St. Joseph
Maumee
Marshall Lawrence
Myers
Fulton
( Manitou )
Kosciusko
Tippecanoe
Oswego
Little Tippecanoe
Secrist
Whitley
Crooked
Noble
( Big)
Shock
Cedar
Shriner
Round
Knapp
Gordy
Hindman
Indian Village
LaGrange
Lake of the Woods
Big Long
Eve
Martin
Oliver
Hackenberg
Messick
Dallas
Atwood
Whitmer
Sloan
Fish
South Twin
Steuben
Green
Marsh
Youngs
North Otter
Snow
Krielbaum
James
Jimerson
Gage
Gooseneck
McLish
(Turkey)
(Long)
(Crooked)
Little Balls?
Riddle?
Clear
(Hamilton)
Basin contains three. Both of these rivers are tributaries of the Wabash,
which enters the Ohio River at the Ilinois-Indiana-Kentucky corner. Most
of the cisco lakes, however, 31 in all, lie in the St. Joseph drainage basin,
188
which enters Lake Michigan from the southeast at Benton Harbor, Michigan. Even the Maumee River system, which drains into Lake Erie at
Toledo, contains one cisco lake in Indiana.
The distribution of cisco lakes in the lake district and within the
various drainage basins is obviously not uniform or random (Fig. 1) .
Rather, there are definite groups or clusters of cisco lakes. Seven major
clusters can be recognized : 1) the Twin Lakes group in Marshall Co.,
2) the Tippecanoe group in Kosciusko Co., 3) the Indian Village group
(perhaps including Shock Lake as well) in Noble Co., 4) the Tri Lakes
group in Whitley Co., 5) the Oliver Lake group in southern LaGrange
Co., and finally 7) the James Lake group in Steuben Co. No more than
a half-dozen of all the reported cisco lakes occur independently of one or
another of these clusters.
That the distribution is not random is well illustrated by the fact that
whereas the North Branch of the Elkhart River has numerous cisco
lakes in the vicinity of Oliver Lake, the South Branch, which drains central Noble Co. and has many lakes, some of them reputed to be fairly
deep, has no reported cisco populations.
If the assumption is correct that all or nearly all the lakes in the lake
district contained ciscoes in early post-Cary time and that populations
have been eliminated by the gradual development of limnological conditions unsuitable for their continued survival, then the persistence of cisco
populations in such definite clusters of lakes can be explained only by the
operation of certain factors controlling the regional limnology of the
lakes.
It is interesting that Willer (1924) reached a similar conclusion for
the lakes of East Prussia containing Core gonus albula. He distinguished
three types of lakes : 1) the ermlandische type, being the deepest and
most strongly oligotrophic ; 2) the oberlandische type, consisting of rather
strongly eutrophic lakes located largely in woodland regions and having
a better developed littoral shelf and a higher organic content in the offshore sediments ; and 3) the masurische type, an intermediate mesotrophic
type with intermediate morphometry as well. The coregonid populations
are confined almost exclusively to the masurische type, being completely
absent from the oberlandische lakes. The three types of lakes are quite
well delimited geographically, indicating the importance of regional factors in their limnology.
Artificial Stocking of Ciscoes
For several decades at the turn of the century the United States Fish
Commission attempted to bolster the stock of whitefish in the Great Lakes
by hatching large numbers of eggs in various Federal hatcheries, and
then planting the fry in the lakes. Less extensive culture of the cisco was
carried out. Occasionally, at the request of state officials or of other
influential persons, fry were planted in various inland lakes. There is
also the possibility, of course, that fry or adult fish from one lake were
189
transplanted into neighboring lakes by interested fishermen. It is necessary, therefore, to examine the available records on stocking to determine
the influence of man in extending the pre-Columbian distribution of the
cisco in Indiana.
The whitefish, Coregonus clupeaformis, has been stocked in several
Indiana lakes on a number of occasions. This species is more oligotrophic
in its ecology than the cisco, and hence would be even less likely to survive
in the generally productive lakes of Indiana. Locally around the Indian
Village chain of lakes in Noble Co., Shock Lake in Kosciusko Co., and
lakes Gage, Clear, and Krielbaum in Steuloen Co., occasional coregonids
as large as 4 lbs. in weight are reported. These are sometimes referred
to as "whitefish" by the local fishermen, as are also specimens only 1 to
2 lbs. in weight, even though these have the same appearance as the still
smaller fish, which are designated "ciscoes." Although none of these
large individuals has been personally examined, it is believed that all of
them are ciscoes, and that the whitefish does not occur in any of the
Indiana lakes. The largest cisco caught by the Lake and Stream Survey
was a female from Knapp Lake (Indian Village chain) weightng 1007
grams. The largest ciscoes caught by Hile (unpublished data) from the
several lakes of the Indian Village chain were 940 g. from Gordy Lake,
775 g. from Hindman, and 810 g. from Indian Village.
According to Levette (1876) the whitefish was introduced into Winona
Lake from Lake Michigan about the year 1860. The fish were reported
to be occasionally caught in the lake, although never abundant. Possibly
the fish that were planted lived for a while without reproducing, and then
died out. The species is definitely no longer present in the lake. The
same can be said for Wawasee, in which 2,000,000 whitefish fry were
planted in 1896 at the request of Eigenmann (Kirsch 1896a). According
to Clark (1894), a total of 215,000 whitefish eggs and fry were planted
in the inland lakes of Indiana during the period 1872 through 1893. The
specific lakes that received these plantings are not mentioned, and there
is no additional information in the early biennial reports of the State Fish
Commissioner of Indiana. During 1890 and 1891 for certain, and possibly
in a few subsequent years as well, experiments were conducted at a hatchery at Warren, Indiana, on the raising of whitefish in ponds (Dennis
1892, and Kirsch 1894a) . There was some measure of success, and the
hatchery superintendent enthusiastically predicted that the whitefish
would become the popular pond fish in the Midwest, and that once its requirements were understood, it could be grown in any water in which
bass will thrive !
Regarding the cisco, there is even less information about the stocking
of the species in the lakes, and the general conclusion is that the preColumbian distribution has not been extended at all, or at least not appreciably, by these practices.
At the hatchery at Warren, Indiana, previously mentioned as raising
whitefish fingerlings in ponds, during the 1893-1894 biennium there were
190
hatched and distributed to the waters of Indiana and adjoining states
100,000 fry listed as whitefish x cisco hybrids (Kirsch 1894a). Even
accepting this report at face value, it is obvious that the distribution of
the cisco in Indiana was not affected by the survival of any of these fry.
Construction of several state-owned fish hatcheries in Indiana was
begun during the 1911-1912 biennium, and completed during the 19151916 biennium. The first hatcheries established were at Wawasee and
Tri Lakes. In the winter of 1914, and apparently only in this one winter,
a large number of cisco eggs were stripped from females at the Tri Lakes
Hatchery, and after being fertilized were "replaced in the nearby lakes
at the most favorable locations" (Miles 1915a). Of the "nearby" lakes,
Big, Crooked, Cedar, and Shriner were already known to have populations
of ciscoes, whereas Round and Blue probably did not. The cisco has
apparently disappeared from Big Lake, so that any stocking in this lake
had no lasting effect. The only hint of benefit is in the case of Round
Lake at Tri Lakes. One of the 11 fishermen reporting fishing for ciscoes
in the Tri Lakes region stated that the species occurred in Round Lake
but was 'not fished. This is at best a very uncertain record. Hence, we
may conclude that the operations described above did not materially affect
the distribution of ciscoes in Indiana.
A few other plantings of ciscoes have been made that are recorded or
reported, and one cannot know how many other similar plantings have
gone completely unrecorded. Miles (1915b) mentioned that several
ciscoes were placed in Crooked Lake (Steuben Co.), but that over a period
of several years nothing was heard further about these fish, and no one
caught any. In late November of 1947, Mr. Floyd DeLancey of Angola
and the personnel of the Fawn River Fish Hatchery transplanted eggs
stripped from Clear Lake ciscoes into Hamilton Lake (Steuben Co.). In
consideration of the limnological characteristics of this lake, the prospects
for at least long term survival of this planting are very poor.
Not until the current cisco law was adopted in 1937 were the fishermen required to return the eggs of the cisco to the waters from which
the fish were taken. It is not known how generally the fishermen comply
with this provision of the law, nor how stringently the Conservation officers attempt to enforce it. Under ordinary conditions of compliance,
this practice would be of doubtful value in influencing the fish populations in the lakes being fished, and very likely would be completely ineffective in extending the distribution of the species.
In the discussion of the temperature-oxygen relations in cisco lakes
and non-cisco lakes, it will be seen that there are very few lakes without
cisco populations at present which likely are capable of supporting the
species. Even if the stocking of ciscoes had been appreciably more extensive than the meager literature records indicate, it is still certain that
most, and perhaps all, of the plantings would have met with failure. Because of the considerable number of lakes still in a rather youthful stage
of development in northern Germany, stocking attempts there would be
191
expected to have a greater probability of success than in northern Indiana,
and yet even in that region success was very limited.
FACTORS GOVERNING THE SUMMER BATHYMETRIC DISTRIBUTION
Except for the Great Lakes where the species occurs primarily in
shallow water, the cisco is generally regarded as a fish of the deep, cold
water of lakes in summer. It tends to occupy the coldest water that still
has sufficient oxygen for its requirements. Because of its needs for both
cold water and fairly high levels of dissolved oxygen, it comes to occupy
an intermediate depth position in summer, limited above by high temperature and below by insufficient oxygen. The thickness of the habitable
zone is largely a function of the typological age of the lake. Perhaps the
species, as Hile and Juday (1941) suggest, can descend temporarily into
the underlying oxygen-deficient water for feeding, and perhaps also during a respiratory crisis can penetrate the thermal barrier of the thermocline into the epilimnion, and there survive after readjusting physiologically to the radically new conditions (Scott 1931).
Birge and Juday (1911) made several observations regarding the vertical distribution of the cisco in a number of Wisconsin lakes. On Sept. 12,
1909, six specimens were collected in Green Lake at a depth of 67 m.
where the oxygen content was very little more than 1 cc. per liter. The
authors concluded that the species does not hesitate to enter water with
this low an oxygen content. In Okauchee Lake ciscoes live just below the
thermocline in summer. When the oxygen content of this water becomes
too small there can be severe mortality of the fish. Of the four years for
which observations are available, there was a severe mortality in 1909.
The oxygen content of the hypolimnion was lowest in this year, reaching
an observed maximum in late summer of only 0.44 cc. per liter. It should
be mentioned here that the cisco mortality in Okauchee Lake is perhaps
also associated with the almost regular development of a minus-heterograde oxygen distribution.2 Scott (1931) suggested that this type of
oxygen distribution was responsible for the September surfacing of the
cisco in Snow Lake, Indiana.
Lower (1913) studied the cisco in northern Indiana during the period
1909-1912. Without presenting any supporting data he concluded that a
temperature of 60° F. (15.6° C.) is fatal to the fish, and that as a consequence the fish are restricted to the hypolimnion in summer.
The first detailed study of the ecology of the cisco was made by Cahn
(1927), but unfortunately the section relating to the bathymetric distribution of the species is most confusing and difficult to interpret. By
means of gill nets Cahn studied the summer distribution of the species in
14 lakes of Waukesha County in southeastern Wisconsin. Although he
determined experimentally in the laboratory that the species if possible
'See p. 198 for a discussion of the Aberg-Rodhe system of classifying the oxygen
distribution in lakes.
192
avoids water temperatures greater than 17° C., he concluded that in summer the cisco takes a position just above the thermocline. As substantiation for this conclusion he stated that if one determines the location of
the thermocline with a thermometer, one can set gill nets just above this
depth and catch ciscoes all summer long, whereas in 43 sets made below
the "thermocline" in nine different cisco lakes, Cahn did not catch a
single cisco.
Cahn did not present any detailed temperature and oxygen data, but
he stated that on one occasion in an unspecified lake, he caught no ciscoes
at 9 m., 11 at 10 m., 2 at 11m., and no ciscoes in repeated attempts in
deeper water. The thermocline at this time was stated to lie at 11 m. In
all probability, Cahn used the word "thermocline" to mean the lower
boundary of the thermocline, as we commonly understand the term. If
this interpretation is correct, then Cahn found the ciscoes in all these
lakes to occur in the lower portion of the thermocline (usual meaning) in
summer, and only very seldom in the hypolimnion.
This interpretation is substantiated in part by the series of data presented by Birge and Juday (1911) for three of the cisco lakes studied by
Cahn. Lake Okauchee has already been discussed. On Sept. 20, 1906,
Lake Nagowicka had an oxygen content of only 0.1 ppm. at 10 m., with
even less at greater depths. The temperature at this level was 16.2° C.,
well up in the thermocline. At 8 m. there was an oxygen content of 4.1
ppm., but the temperature was 20.1°, which is generally considered to be
at or even above the upper limit of tolerance of the cisco. Hence, on this
date, only a thin stratum possibly less than a meter thick at the uppermost part of the thermocline provided suitable conditions of temperature
and oxygen for the cisco.
In the west basin of North Lake on Sept. 4, 1907, there was essentially
no oxygen from 6 m. to the bottom. Yet the temperature at 5 m. was
already 20.5°, and the oxygen content 6.2 ppm. In this lake very likely
the ciscoes were even more sharply restricted in their late summer bathymetric distribution.
Several other examples of cisco lakes in southern Wisconsin might be
mentioned here, although they were not studied by Cahn. In Lake Mendota at Madison the cisco population is forced by insufficient oxygen in
deeper water to live at fairly high temperatures in the upper part of the
thermocline (Birge and Juday 1911). Pearse (1921a) fished the lake
with gill nets from June 24 to Sept. 5, 1919. The four ciscoes caught on
Aug. 20 and Sept. 3 were from depths of 10 to 12 m. Quite a number of
perch (Perca flavescens) were caught at the same and somewhat greater
depths during this period. Pearse did not make any determinations of
dissolved oxygen, but it is known from the studies of Birge and Juday
(1911) that the oxygen of the hypolimnion usually becomes completely
used up during summer stagnation. In 1906, the year for which the best
series of records is available, there was no oxygen at all at 12 m. for a
period of three weeks in August, and even at 10 m. the supply was so
193
small (less than 0.1 cc. per liter) "that animals requiring a moderate
supply of oxygen, such as fish, could not have lived at this depth during
this time." This stratum was located at the bottom of the thermocline
in August and near the middle in early September. Water temperatures
of less than 20° C. extended upward to 9 m. at this time, and the ciscoes
presumably were living in this very thin stratum of warmer water with
somewhat less severe conditions of dissolved oxygen.
Lake Geneva in southern Wisconsin is a large lake, with an area of
2210 ha. and a maximum depth of 43.3 m. (Juday 1914). The oxygen
content of the hypolimnion becomes considerably reduced in summer,
although it evidently remains adequate for fish life down to about 30 m.
(Birge and Juday 1911). During the period Aug. 8-25, 1920, Pearse
(1921b) caught ciscoes at depths between 15 and 25 m. Other species
caught in this stratum were the rockbass ( Ambloplites rupestris), smallmouth bass ( Micropterus dolomieui), yellow perch, and walleye (Stizostedion vitreum). Pearse observed the northern pike ( Esox lucius) to be
feeding on the cisco, even though the pike at that time was never taken
below 15 m. In 1941 Nelson and Hasler (1942) likewise found that the
larger individuals of northern pike were feeding almost exclusively on
ciscoes, even though the bathymetric ranges of the two species barely
overlapped. These investigators also captured a number of other species
along with the cisco : yellow perch, rainbow trout (Salmo gairdneri),
northern pike, largemouth bass ( Micropterus salmoides), smallmouth
bass, and white bass ( Morone chrysops). Only ciscoes were caught below
a depth of 60 ft. (18.3 m.). Hence, in Lake Geneva an upward displacement of the cisco in late summer brought about presumably by declining
oxygen levels below, brings the species into contact with quite a number
of other species, and subjects them to predation by such a typically
shallow-water fish as the northern pike.
Finally, in Green Lake with a maximum depth of 72.2 m., making it
the deepest inland lake in Wisconsin, oxygen levels remain high almost
to the bottom throughout the summer. Pearse (1921a) found that at
this season the ciscoes occur exclusively at depths greater than 40 m.,
where they live alone. Hence, where oxygen levels are adequate the
species may prefer to live far below the thermocline, utilizing only a relatively small portion of the total volume of water physiologically available. In a somewhat similar instance of summer bathymetric distribution
correlated with high oxygen levels, Thienemann (1933) found a race of
Core gonus albula, feeding on benthos rather than plankton. He postulated
that this species was originally a bottom feeder, but that it was forced to
change its habits by the declining oxygen levels of the deepest water with
increasing typological age.
Hile (1936a) and Hile and Juday (1941) described the summer bathymetric distribution of the cisco in four lakes of northeastern Wisconsin
in relation to the temperature and oxygen stratification of the water
and in relation to other species occurring along with the cisco. In Trout
194
and Clear lakes having fairly high levels of oxygen throughout the hypolimnion, the species occurred quite generally in the hypolimnion. In
Silver Lake, which experiences a moderate oxygen deficit, the species became concentrated in a stratum from 10.5 to 15.5 m. In Muskellunge
Lake, the lake with the most severe oxygen depletion in the hypolimnion,
the ciscoes in 1931 were largely confined to a stratum only a half-meter
thick, from 9.5-10 m. On Aug. 26, 1931, this stratum was located in the
middle of the thermocline, with a temperature range of 16.3 to 14.8°, and
an oxygen range of 4.6 to 1.6 mg./1. In 1930 and 1932, conditions were
not quite so extreme, the fish being largely concentrated in each case in
a stratum about 2 meters thick. This stratum in 1932 had thermal limits
of 13.8 and 10.4°, and oxygen limits of 2.7 and 0.4 mg./1. No chemical
data are available for 1930. By virtue of the severe oxygen utilization
in the hypolimnion, the fish are forced upwards into the lowermost portion of the thermocline. It is interesting that at least in Muskellunge
Lake even at severely reduced levels of dissolved oxygen the negative
tropism of the species to the thermal gradient continues so strong that the
fish do not ascend very high into the thermocline, where temperatures
are still adequate and oxygen levels much more satisfactory. Hile (1936a:
259) concluded, "As a result of this deficiency of oxygen in the deeper
strata, the ciscoes are forced out of the cooler strata and by reason of
their preference for cool water and their need of oxygen become concentrated in that stratum that has the lowest temperature available and
yet contains sufficient oxygen to support life." Hile thought this lower
limit might be as little as 1 mg./1. In a later paper, however, Hile and
Juday (1941) suggested that the cisco, like the perch, may make temporary sorties for food into deeper water with insufficient oxygen, and
hence the lower bathymetric limit as determined by capture may well be
below the lower physiological limit for oxygen and carbon dioxide.
In these four Wisconsin lakes, various other species of fish were found
associated with the cisco in summer, varying with the typological age of
the lake and the dependent bathymetric distribution of the cisco. The
four lakes arranged in order of decreasing oxygen content in the hypolimnion are : Trout, Clear, Silver, and Muskellunge. In Trout Lake, the
ciscoes are associated with such polyoxybiontic cold-stenotherms as the
lake whitefish (Coregonus clupeaformis), lake trout (Salvelinus namaycush), and the burbot (Lota iota). In Clear Lake the walleye was caught
at all depths with the cisco, and in addition a rock bass and five yellow
perch were taken. None of the more oligotrophic stenotherms was present, however. In Silver Lake where there is considerable depletion of
oxygen in the lower hypolimnion, the ciscoes are forced into the upper
portion of the hypolimnion, and here they live largely by themselves.
Only one perch was caught with them. Finally, in Lake Muskellunge,
which develops the most severe oxygen deficit of these four lakes, the
ciscoes are intimately associated with small perch in late summer, and
may well be in competition with them for food. Hence, with decreasing
195
content of oxygen in the hypolimnion, the ciscoes are forced higher in
the water and come into progressively greater contact with warm water
species. Hile and Juday emphasize the fact, however, that the lower
bathymetric distribution of any particular warm water species seems to
vary considerably from one lake to another.
Allequash Lake in northern Wisconsin is perhaps even more interesting as an example of the extreme environmental conditions the cisco can
tolerate, and of the other species of fishes the cisco can be brought into
contact with as it is forced progressively higher in the thermocline. The
lake has an area of 142 ha. and a maximum depth of only 7.5 m. (Juday
1914) . On Aug. 20, 1907, the only date for which data have been published, the oxygen content at 5 m. where the temperature was 19.2° C.
was 5.7 ppm., and at 6 m. at a temperature of 12.4° only 0.9 ppm. (Birge
and Juday 1911). Certainly the ciscoes must have been concentrated in
a very thin stratum at this time. Restriction of the fish to the upper
part of the thermocline brought them into direct contact with other species.
Hile (1936a: 317) records that, "Along with the 70 ciscoes captured in
1930 were taken 1 blue gill, 15 suckers, 22 pike-perch, 32 rock bass, and
182 perch." Conditions necessary for the survival of the cisco must be
near the tolerance limit in this lake.
Fry (1937) studied the seasonal movements of the cisco in Lake
Nipissing, a large lake in southern Ontario. and correlated these with
chemical and physical conditions. In this lake, the species moves into
deep water in late spring and early summer, different size classes and
sexes migrating at different times. Through depletion of oxygen in the
hypolimnion, the fish become concentrated immediately beneath the
thermocline in late summer. In general, the species is confined to temperatures below 20°, which Fry regarded as a critical limit for the species.
At no time during six seasons of study were any considerable numbers of
ciscoes taken in water that had been above 20° for very long. Moreover,
once the fish get into the hypolimnion, their negative response to the
sharp thermal gradient of the thermocline is so pronounced that even
during the initial stages of autumnal cooling, as the thermocline sinks
deeper the fish continue to remain below this thermal gradient in water
quite low in oxygen, even though the epilimnion by this time has cooled
below 20°.
More recently Smith3 has described the seasonal bathymetric distribution of the species in Green Bay of Lake Michigan. In late May the
fish are confined to depths less than 30 ft., most of the fish being concentrated in the uppermost 15 ft. In June, and especially in July, the
fish tend to occur only at depths greater than 30 ft. In July the water
temperature of the upper 30 ft. varied between 18.3 and 21.5° C., and
Smith concluded that the only relationship of the lake herring to temperature was the avoidance of water warmer than about 20° C. However, the
Smith, S. H. 1955. Life history of the lake herring of Green Bay, Lake Michigan.
167 typed pages. To be published as a Fishery Bulletin by U. S. Fish & Wildlife Service.
3
196
influence of increasing water temperature in bringing about the downward movement of the species is somewhat obscure from the data. Thus,
on June 10-12 the fish were already largely confined below 30 ft., although surface temperatures at this time varied from 12.9 to 15.1°, and
the temperature at 30 ft. was 12.3-13.7°. The upper water temperatures
in late May were almost this high, and yet at this time, as already stated,
the fish were largely above 30 ft. in their bathymetric distribution. The
oxygen content of the water does not seem to be influencing these
movements.
In summary, the cisco tends to occupy the entire hypolimnion during
the summer if adequate levels of oxygen are present. In clinograde lakes
(see below) the fish are forced progressively higher by depletion of oxygen below, until they become confined largely to the uppermost hypolimnion and lowermost thermocline. With still further depletion, the
fish may be forced into the upper part of the thermocline, although judging by Muskellunge Lake and even Nipissing they seem to resist this displacement as long as possible. Some degree of stenothermy persists in
the species, however, because there are no records of the cisco occurring in
the warm surface watters of our lakes during the summer.
INFLUENCE OF AGE ON OXYGEN-TEMPERATURE REQUIREMENTS
Among the coregonids, and apparently among fishes in general,
physiological plasticity and adaptability declines with age. Thus, although the coregonids as a group are considered typically to require relatively cold water and high levels of dissolved oxygen for their survival,
first summer young of at least three species have been successfully reared
in shallow, warm-water ponds.
At the early fish hatchery at Warren, Indiana (Dennis 1892, and
Kirsch 1894a), whitefish (Coregonus clupeaformis) were reared in ponds
to an age of 6 months before transplanting. The first attempts were not
too successful, in that only 800 fingerlings 2 inches long still survived 3
months after the stocking of 100,000 fry in a small pond (Dennis 1892).
Apparently the later attempts were more successful, although no data are
presented. Furthermore, no data are presented on the temperature extremes to which the fish were subjected in these ponds.
Slastenko (1931, as quoted by Sukhoverkhov 1943) was able to raise
whitefish (species not stated by Sukhoverkhov, although very likely
Coregonus lavaretus) in carp fattening ponds during their first summer.
The most extensive experiments, reported on in considerable detail,
were carried out by Sukhoverkhov (1943) on Coregonus albula and one of
its varieties with a faster rate of growth. Fry from hatchery jars were
stocked in carp ponds up to 150 ha. in area at the rate of 200 to 5000 per
ha. No places in these ponds were deeper than 3 m., and the average
depths were only 0.8-1.5 m. Permanent stratification was therefore out
of the question. Temperatures in these ponds reached maxima of 26-28°
C. on individual days in July and August, and occasionally the oxygen
197
content of the water fell to rather low levels over night. Survival on the
whole was good, and the rate of growth tended to be much faster than
in natural waters. The fish fed on a variety of littoral entomostraca that
normally are not encountered by wild populations. Moreover, Dryagin
(1939, as reported by Sukhoverkhov 1943) found C. albula in some of the
lakes of the Kalininskoi District which were so shallow that summer
stratification did not occur at all or was only transitory. These results on
C. albula are of particular interest in the present study because of the
close morphological and physiological similarity of the species to C.
artedii, which, according to Bauch (1953), is somewhat intermediate
morphologically between C. albula and the species collectively known as
"grosse Marane."
The greater tolerance of young coregonids to high temperatures is
indicated by other observations as well. Fry (1937) observed in Lake
Nipissing that the young ciscoes are the last to move into deep water as
the lake warms up in spring. Kennedy (1941) noted that in the movement of C. clupeaformis from one lake to another, apparently induced by
unfavorable temperatures in the one, the smallest individuals were the
last to migrate.
There is also some evidence that young coregonids are more tolerant
of low oxygen levels than are larger and older fish. Willer (1929)
pointed out that this is known for trout, and that presumably the same
holds true for C. albula. He ascribed the mortality of the majority of
individuals of this species at the end of their second year of life in
Nariensee to the low oxygen levels in the hypolimnion. Furthermore,
Bauch (1949) observed an almost complete disappearance of C. albula 3-5
summers old from Mochelsee at the beginning of summer stratification
in 1944, which he attributed to the disappearance of oxygen from the
hypolimnion. Younger fish continued to live in the lake. Eichler (1940)
observed a heavy mortality of the species in LOwentinsee in 1938, which
he ascribed to the disappearance of oxygen from the hypolimnion. The
kill was not complete, however, because in 1944 Bauch (1949) again
caught fish in this lake. He believes that only the young fish are able
to withstand the severe hypolimnial oxygen depletion that develops.
One of the interesting regional differences between continental European lakes and the mid-continental lakes of North America is that the
summer stratification of the former is usually much less sharply developed. The epilimnion frequently has temperatures below 20° throughout the summer, and the gradient of the thermocline is much less steep
than in the North American lakes. As a result the thermocline does not
seem to be such a pronounced barrier to the upward movement of C. albula
as it is to C. artedii in their respective lakes. There is abundant evidence
based both on visual occurrence of schools of fish and on food habits that
C. albula makes food sorties into the too-warm epilimnion, much as the
Wisconsin ciscoes apparently make food sorties into the deep water with
insufficient oxygen (Hile and Juday 1941).
198
In lieu of evidence to the contrary we can assume that the young of
C. artedii likewise are more tolerant of high temperatures and low oxygen
than are the larger and older individuals in the populations.
As environmental conditions become progressively more severe for
C. artedii and C. albula in their respective lakes, one can suppose that in
years of extreme oxygen deficit, involving the thermocline as well, many
fish will be unable to adapt to the extreme conditions of oxygen and temperature and will perish. The individuals involved will be primarily the
large and old members of the population. As long as some of the smallest
individuals survive, however, the population can continue to exist. Complete elimination of the population might result when such severe environmental conditions develop in two or more years in succession, or
when such a severe year follows one or more years without recruitment
to the population, resulting in an age-frequency structure truncated below
by the lack of the younger and physiologically more adaptable individuals.
SUMMER BATHYMETRIC DISTRIBUTION IN INDIANA LAKES
In the summers of 1951 and 1952 the Indiana Lake and Stream Survey
began a study of the summer bathymetric distribution of the cisco. A
total of 348 specimens was caught in seven different lakes during the two
seasons, as summarized in Table 4.
4. Ciscoes netted by the Indiana Lake and Stream Survey during the summers
of 1951 and 1952.
1952
1951
Lake
County
TABLE
Indian Village
Hindman
Gordy
Knapp
Tippecanoe
Oliver
Myers
Noble
,t
11
Kosciusko
LaGrange
Marshall
6
1
10
4
26
53
1
1
48
203
Gill nets of various kinds were fished in several ways. During the
second summer the standard procedure was to set two gill nets in tandem
on the bottom and two in tandem diagonally through the water from
surface to bottom in the manner described by Fry (1937). Sometimes
"experimental" gill nets were used, each containing successive webbing
sections of 11/2, 2, 21/2, 3 and 4-inch extension measure, and at other times
1
standard gill nets of either 2 or 2 /2-inch extension measure were used.
The position of the ciscoes in the nets was kept track of by relating each
fish to the nearest numbered float of the corkline. Depth soundings at
both ends of the net, and usually in the middle as well, served as the
bathymetric controls.
In the rest of this paper, where it is necessary to typify or describe
the type of oxygen distribution in a lake, the system proposed by Aberg
and Rodhe (1942) will be used. The following types of oxygen distribution are recognized in stratified lakes : ortho grade, in which there is no
199
decline (subtype a) or only a very gradual decline (subtype b) in oxygen
content with increasing depth ; clino grade, in which the oxygen curve is
similar in shape to the temperature curve of a temperate, stratified, holomictic lake ; plus-heterograde, in which there is a pronounced peak of oxygen concentration in or near the thermocline ; and minus-heterograde, in
which there is a pronounced decline in oxygen content in or near the
thermocline (the so-called "oxygen notch"), with recovery at greater
depths. In many respects this system is a restatement of other descriptions of oxygen distribution proposed earlier, and yet there is a simplicity
in the concepts and terminology which recommends it. One of the advantages of this system is that the types of oxygen distribution are described without reference to the primary trophic level of the lake, even
though the orthograde and clinograde curves are usually associated with
oligotrophic and eutrophic lakes, respectively. There are all gradations
between the various types, however, so that it is sometimes difficult to
assign a particular distribution to any one of them.
A. Indian Village chain of lakes (Noble Co.)
Hile (1931) recorded the cisco as occurring in three of this chain of
six small lakes—Indian Village, Hindman, and Gordy. No ciscoes were
caught in Rider or Duley, and Hile did not fish Knapp Lake. The cisco
populations in Indian Village, Hindman, and Gordy are still maintaining
themselves (Table 4), and in addition it is now known that Knapp Lake
also contains the species. The Survey crews caught no ciscoes in either
Rider or Duley. This chain of lakes is interesting in that all of them
except Knapp are quite shallow and small in area (see Table 5), and exhibit severe oxygen deficits in the hypolimnion which force the ciscoes
into the uppermost hypolimnion or even into the thermocline in summer.
(A) 1. Indian Village Lake
The only previous report as to the depth at which ciscoes occur in
Indiana lakes in summer, based on actual netting records and the relation
of this stratum to the temperature and oxygen characteristics of the
water, is that of Scott (1931) for Indian Village Lake. Hile set a 31/4inch extension measure gill net, which was 12 ft. in depth, in the deepest
part of the lake on July 21, 1929, and caught 18 ciscoes in the upper
two feet only of the net. The depth of the central portion of the lake is
6.3 m. According to these relationships, the fish were caught in the
stratum from 3.64 to 4.25 m. below the surface. There is no assurance
from the catch data that there were no ciscoes at shallower depths than
this, although that is not too likely because of the temperature relationships.
Scott presents an oxygen curve for the lake for June 27, about a month
before the ciscoes were netted. At that time the oxygen content varied
from 5.6 ppm. at the upper level of this stratum to 3.4 ppm. at the lower.
A month later, there would be no reason to expect any appreciable change
200
at the upper level, although at the lower boundary the oxygen content
might have been still smaller.
Temperature data for this period are not available. Since, however,
thermal stratification is largely a function of the surface features of a
lake and its watershed topography, and for such small lakes, at least,
varies relatively little from one year to another, more recent thermal
data can be used.
On Aug. 18, 1951, the interpolated temperature at 3.6 m. was 18.8°,
and at 4.2 m., 16.4°. This zone lies in the upper portion of the thermocline. On July 31, 1952, water temeperatures at the same levels were
19.0° and 16.2°, respectively. In spite of the considerably steeper thermal
gradient in 1952 than in 1951, the thermal limits of this stratum are very
similar in the two years.
As closely as could be determined from the field data, the six specimens caught in 1951 were taken at a depth of approximately 4.6 m. The
oxygen content at this level was approximately 4.2 ppm., and the temperature was 14.5°. If the temperature tolerance in this year was 19°,
as it seemed to be in 1929, then the fish could have ranged upward to
3.5 m. In 1951 the lake had a plus-heterograde oxygen distribution, with
the maximum occurring at 4 m. The decline below this depth was very
sharp, so that the fish would not have been able to remain continuously
in water much more than a few decimeters below this level. Such a photosynthetic maximum of oxygen in the thermocline is probably of great significance in facilitating the survival of the cisco in this lake and in a
number of other small Indiana lakes. There is evidence from at least one
lake (Myers) that a photosynthetic maximum is of regular occurrence
in some of these lakes, although in 1952 the oxygen distribution in Indian
Village was clinograde. The depth at which the single cisco of this year
came from could not be determined from the field data.
The marginal conditions under which the ciscoes are forced to live in
this lake are strikingly illustrated by the warm water fishes occurring
with this species. One of the six specimens caught in 1951 was partially
eaten, supposedly by the bowfin (Amia calva) 58 cm. long which had become entangled nearby in the same net. In four other sets of gill nets at
this depth, or at most 2 ft. shallower, no ciscoes were caught, but there
were instead six white suckers (Catostomus commersoni), one brown bullhead (Ictalurus nebulosus), and one black crappie (Pomoxis nigromaculatus). In another set only a little shallower than this there were ten common suckers, one grass pickerel (Esox vermiculatus), seven bluegills
(Lepomis macrochirus), one golden shiner (Notemigonus crysoleucas),
and two warmouth bass (Chaenobryttus coronarius).
Thus, not only is the bathymetric distribution of the cisco greatly restricted in this lake in late summer, but it lies immediately below or even
overlaps to a slight extent the shallow water habitat of the warm water
species. The stratum occupied lies in the upper portion of the thermocline roughly between temperature limits of 19 and 15°, and at oxygen
201
concentrations roughly between 8 and 3 ppm.
( A) 2. Hindman Lake
Hile (1931) caught 11 ciscoes in Hindman Lake on Aug. 12-13, 1929,
but unfortunately for the present purpose he did not discuss their bathymetric distribution. The single cisco caught in 1951 is also from an
indeterminable depth. However, the late summer stratification in this
lake is so extreme there is only a very thin stratum in which the fish can
live. If one assumes that the upper thermal limit of the species is 20° C.,
as Fry (1937) concluded, and that the lower oxygen limit is approximately 3 ppm., then only the stratum from 3.2 to 3.8 m. provided these
conditions on July 26, 1952. On Aug. 26, 1953, the depth limits of this
zone were 3.7 and 4.3 m. In both years the lake exhibited a strong plusheterograde oxygen distribution early in the summer, somewhat less
strong later. Since the odor of ILS was already pronounced in water
samples from 5 m., it is likely that the photosynthetic release of oxygen
in the upper thermocline is important in maintaining the species in this
lake, too.
(A) 3. Gordy Lake
Hile (1931) studied 24 ciscoes from Gordy Lake, 11 of which were
caught on July 23, 1929. Again, regretfully, no data are given on bathymetric distribution. The 10 ciscoes caught by the Lake and Stream Survey in 1951 came from a depth of about 4.5 m., as near as can be determined. The single specimen caught in 1952 came from about 5 m. Its
head had been eaten off, and nearby in the net in somewhat shallower
water were two garfish (Lepisosteus sp.). It is not believed, however,
that the gars ate the cisco, but rather that a bowfin did, as in Indian
Village Lake, because another set from approximately the same depth
yielded a bowfin and a bullhead. In 1951 nine bluegills were taken in the
same set as five ciscoes. Hence, the bathymetric ranges of these two
species if not slightly overlapping at this time were at least contiguous.
Both in 1952 and 1953 Gordy Lake had a strong plus-heterograde
oxygen distribution, with the oxygen maximum occurring in the upper
part of the thermocline at a depth of 4 m. and a temperature of 19° C.
Contrary to the conditions in Indian Village and Hindman lakes, there
was not the extremely rapid cutoff in oxygen below this maximum, which
may well be related to the greater hypolimnial volume in Gordy Lake. As
a result concentrations of oxygen adequate for ciscoes persisted down to
6 m. or even a little deeper. Based upon toleration of temperatures up
to 20° and dissolved oxygen down to 3 ppm., the cisco stratum in these
two years extended from 3.8 to 6.3 m., and from 3.9 to 6.2 m., respectively,
in late summer.
(A) 4. Knapp Lake
During the period Aug. 13 to 17, 1951, four ciscoes were caught at
202
depths of 6.0 to 8.5 m. Nets set at depths greater than 9 m. did not catch
any fish.
Chemical and physical data are available for 1952 and 1953. In both
years the oxygen distribution was plus-heterograde, although in 1953 this
had changed to clinograde by late August. On July 23, 1952, the stratum
from 4.5 to 12.1 m. had conditions assumed to be suitable for cisco, and
on Aug. 26, 1953, from 4.9 to 8.8 m. These zones extend through the
lower 2/3 of the thermocline into the uppermost part of the hypolimnion.
It is interesting and probably significant that all four lakes in the
Indian Village chain which maintain cisco populations tend to develop
a plus-heterograde oxygen distribution. This is important particularly
in the two shallowest lakes in helping to maintain adequate levels of oxygen in the upper and middle thermocline, where the cisco lives in late
summer. Here the temperature is so high that warm water species from
the epilimnion, including predators, can occur along with the ciscoes.
5. Tippecanoe Lake ( Kosciusko Co.)
Tippecanoe Lake was fished during the period July 10-27, 1951, with
various combinations of two experimental nets and two standard 3-inch
nets. The nets were set off the bottom as well as on the bottom. Many
sets yielded no fish at all. Nets set offshore at water depths of 10 m.
or less did not catch any ciscoes, although one specimen each of rainbow
trout, bluegill, and white sucker was taken at depths almost this great.
Ciscoes first began appearing at 12 m. (there is one somewhat questionable record for 11 m.), reached their maximum concentration at 15-18 m.,
and then continued in small numbers to depths at least as great as 25 m.
It is quite likely that this early in the season when the oxygen deficit is
not yet very extreme, the ciscoes occur throughout the hypolimnion. No
other species of fish were caught along with the cisco.
Tippecanoe is a large lake and is the deepest in Indiana, with a maximum depth of 37.5 m. Moreover, the hypolimnial volume (that below a
depth of 10 m.) is large, comprising 46 percent of the total volume of the
lake. In this respect, it is almost on the border line between oligotrophic
and eutrophic lakes in Thienemann's original statement of the concept.
However, the lake is definitely not oligotrophic. It regularly develops an
oxygen notch in the thermocline early in the summer, and as the season
advances, the oxygen content of most or even all of the hypolimnion can
be reduced to very low values. In 1951, the oxygen notch was less
strongly developed and the oxygen content of the hypolimnion remained
higher than for any other year on record. On Aug. 26 the oxygen content
at 10 m. was 1.2 ppm., but below here it varied between 3.4 and 4.5 ppm.
down to at least 30 m. There is little reason to believe that these levels
of dissolved oxygen presented any difficulties for the fish.
Birge and Juday (1911) present a series of observations on Tippecanoe for Sept. 17, 1909, in which the oxygen content at 10 m. was only
0.16 ppm., and the maximum oxygen content of the hypolimnion was only
203
3.3 ppm. Scott (1916) likewise found a more extreme stratification than
in 1951, although not quite so extreme as in 1909. On Aug. 12, 1912, the
oxygen content at 10 m. was 0.27 ppm., and the maximum concentration
in the hypolimnion was 3.66 ppm. Apparently, ciscoes can survive quite
well at these higher oxygen levels. In some years, however, for which
observations on the water chemistry are unfortunately lacking, conditions
become extreme enough to bring about extensive mortality. 1954 is reported to have been such a year. It is believed that the hypolimnial oxygen content below the 10-meter level becomes so greatly reduced at such
tims that the fish are unable to survive, and they rise to the surface.
This seems to be a much better example of the phenomenon reported by
Scott (1931) for Snow Lake, in which the September surfacing is believed to result from the fish becoming trapped below the oxygen notch
and suffering temporary asphyxiation (see p. 221) .
6.
Oliver Lake (LaGrange Co.)
Oliver Lake is a deep, marl-type lake, which tends to maintain quite
high levels of dissolved oxygen in most of the hypolimnion throughout the
summer. Of all the lakes in Indiana it, along with James Lake in Steuben
Co. and Crooked Lake in Whitley Co., most closely approaches the oligotrophic type in terms of summer oxygen distribution. This summer oxygen pattern is reflected in the summer bathymetric distribution of the
ciscoes.
A total of 48 ciscoes was caught in Oliver Lake in 1952, 40 during the
period July 15-18, and 8 during Aug. 12-15. These fish were all taken at
depths varying from 9.8 to 23 m. Two specimens may possibly have been
caught in water as shallow as 8.5 m. ; but since these were from a diagonal
set, the records are not above suspicion. Only two other fish were taken
with the ciscoes—a rainbow trout at 11 m., and a white sucker at 13 m.
The former tends to be a cold water species, and the latter frequently
extends its range into cold water.
Based on these catch records, the cisco in Oliver Lake lives at tempera0
tures 10 and below in summer, and at oxygen concentrations generally
between 5 and 8 ppm. Even as late as September 12, there were still 2.5
ppm. of oxygen at a depth of 20 m. Contrary to the lakes of the Indian
Village chain, the ciscoes here are not driven upward into the thermocline
in late summer by reduced levels of oxygen in the hypolimnion. The
fish remain in the hypolimnion all the time and apparently do not enter
the thermocline, even though conditions here are adequate for survival,
indicating that the hypolimnion is the preferred habitat of the species,
and that the warmer water of the thermocline is used only when the
hypolimnion is no longer habitable.
7.
Myers Lake (Marshall Co.)
This is one of the more interesting lakes in Indiana. Regularly during
five successive summers (1951-1955) it has developed and maintained
204
a very pronounced photosynthetic oxygen maximum centered at about
8 m. in the lowermost part of the thermocline, resulting in the highest
levels of dissolved oxygen known from any Indiana lake. The highest
concentration recorded is 23.2 ppm. at a temperature of 12.1°, and the
organism largely responsible for this condition is Oscillatoria Agardhii
Gom. Moreover, below this oxygen maximum at a depth of 9.5 to 10 m.,
there is usually an extremely sharp decline in oxygen content to just a
trace or none at all within a depth of a half-meter (Fig. 6). W. R. Eberly
has been attempting to discover the factors responsible for the consistent
development of this oxygen maximum, and its effect on the overall productivity of the lake.
Using Birge's definition of a thermocline in temperate lakes as a
thermal gradient equal to or exceeding 1° C. per meter of depth, then
the mid-summer boundary between the thermocline and hypolimnion lies
at 9.0±
0.2 m. Because of insufficient oxygen in deeper water, the ciscoes
are limited in their summer bathymetric distribution to the uppermost
meter or two of the hypolimnion, plus whatever portion of the lower
thermocline they are forced to invade.
A total of 256 ciscoes was captured in the lake during 1951 and 1952.
Certain data for these fish have already been partially organized by
Davidoff,4 although the analysis of the bathymetric distribution is modified and developed further in the present paper.
During the period July 30 to Aug. 10, 1951, 53 ciscoes were netted at
depths between 7.6 and 10.7 m., with the bulk of the fish apparently occurring right around 9 m. On Aug. 13, the thermal limits of this stratum
were 12.9° and 8.8°. Because of the location of this stratum with reference to the thermocline, it may be presumed that there were no significant changes in temperature during the preceding two weeks. The peak
of the oxygen maximum occurred at 8 m. on this date, with a value of
18.9 ppm., and a concentration of 8.1 ppm. at 10 m. Although no oxygen
sample was collected at 11 m. on this date, it is likely from subsequent
more detailed studies on the limnology of the lake that the oxygen cutoff
began at 10 m., and that by a depth of no more than 10.7 m. there was
probably very little dissolved oxygen remaining. Hence, in midsummer
of 1951 the Myers Lake ciscoes were inhabiting a stratum only 2-3 m.
thick at the thermocline-hypolimnion junction. The fish were probably
reacting negatively to the thermal gradient, which kept them from occurring at higher levels in the thermocline, as in Indian Village and Hindman Lakes. A few warm water species were occurring with the ciscoes.
A bottom set at a depth of 10 m. caught three brown bullheads and one
bluegill along with three ciscoes.
In 1952, the lake was fished at three different times during the summer, and greater care was taken to ascertain the particular depth at which
4
Davidoff, E. B. 1953. Growth, response to netting, and bathymetric distribution
of the cisco, Leucichthys artedii (Le Sueur), in Myers Lake, Indiana. Univ. Michigan,
MS-thesis manuscript. iv + 31 typed pp.
205
each cisco was caught. The results for the bottom sets are more reliable
than for the diagnonal, because the latter as a result of sagging did not
always fish at the calculated depths.
Eighty-six ciscoes were caught during the period June 26 to July 3,
1952. Most of these fish were captured at depths varying from 7.0 to
10.4 m. Two specimens were apparently caught at 10.7 m. and one at
11.9; these three specimens were all dead when hauled to the surface. At
lesser depths, one-half to three-fourths of the fish were still alive after
a 12-hour set. Eighteen ciscoes were taken in the upper of two experimental nets set on the diagonal. The bottom of this net was at a depth
of 7 m. If the net was stretched straight along the diagonal line from
this depth to the surface, then some of these fish could have been caught
in depths as shallow as 5.2 m. Because of known instances in which nets
set diagonally sagged, it is entirely possible that this net was sagging a
bit. Furthermore, in view of what has already been stated about the
bathymetric distribution of the cisco in 1951, it is considered quite unlikely that any of the fish were actually living in water shallower than
6.5 m. this early in the summer.
On June 26, the temperature at 7 m. was 11.9° C., and at 10 m., 7.5°.
Oxygen concentrations were 17.0 ppm. at 7 m. and 0.8 ppm. at 10 m. The
oxygen maximum occurred at 8 m. on this date, with adequate concentrations (4.7 ppm.) down to 9.5 m. (see Fig. 6). If the three specimens calculated as having been caught at depths greater than 10.4 m., where the
oxygen content at this time was only about 0.5 ppm., actually came from
these depths, than it is possible that they had been making quick sorties
into this lower water, such as already postulated for Lake Muskellunge
in Wisconsin (Hile and Juday 1941). The fact that all three fish were
dead when recovered lends support to this idea.
Two rainbow trout were caught in approximately 9 m. of water, and
were alive when taken.
During the period July 22 to July 25, 1952, one diagonal set yielded 27
ciscoes from the upper net. If the assumption is made that the net was
not sagging on this occasion, then these fish came from depths between
5.2 and 6.5 m. This statum was near the top of the thermocline. Its
thermal limits were 18.0° and 12.5°, and its oxygen limits 9.3 ppm. at
the top and 14.4 ppm. at the bottom. On this date, the oxygen maximum
of 20.2 ppm. occurred at 8 m., and oxygen concentrations 3 ppm. or greater
extended downward to 10.5 ppm. In light of what has already been
reported in this paper concerning the strong negative tropism by the
cisco to the steep temperature gradient of the thermocline, and the consequent pronounced tendency of the species to remain in the deepest water
with adequate levels of dissolved oxygen, it is difficult to understand why
these fish would vacate the lower half of the thermocline when the oxygen
concentrations here were still much more than adequate for their needs.
Possibly they were responding negatively to the large concentrations of
Oscillatoria at depths of 8 m. and greater, particularly the flocculent
206
senescent algae near the lower limit of the thermocline, or perhaps the
fish were actively avoiding the excessively high concentrations of oxygen
in the middle thermocline. Sukhoverkhov (1943), for example, found
that in one pond in which the oxygen content reached an extreme value
of 39.2 mg./1., there was a loss of Core gonus albula, supposedly from the
high oxygen levels, but the carp occurring in the same pond were not
appreciably affected.
That the ciscoes occur higher in the thermocline in late summer, even
though oxygen levels for some distance deeper are still adequate, is
further demonstrated by the catch data of Aug. 18-21. Eighty-four
ciscoes were caught at this time. The calculated depths of 34 ciscoes
caught in diagonal sets (4.9-6.1 m.) were somewhat less than those of the
50 fish caught in bottom sets (4.9-8.5 m.), which may be accounted for in
part by the tendency of the diagonal nets to sag. Even allowing for this
possible source of error, however, it is significant that no specimens were
caught below 8.5 m. It is true that at this time the oxygen conditions
in the upper part of the hypolimnion were greatly reduced over what they
had been only a week previous, so that, for example, at 9.5 m. the oxygen
content was only 2.4 ppm. There is no apparent reason to question the
bathymetric distribution as calculated from the field data, and one must
conclude that the ciscoes were avoiding the stratum from 8.5 to 9.5 m.
for some reason.
This higher bathymetric distribution in late summer brought the cisco
into direct contact with several warm water species. One warmouth bass
was taken at 7.3 m., and a brown bullhead was taken at 6.1 m., flanked
on either side in the net by ciscoes. Bullheads were fairly abundant at
depths down to 4.3 m. Rainbow trout, however, tended to occupy the
same stratum as ciscoes throughout the summer. Four specimens were
captured during this late-summer period at depths of 5.2-8.2 m.
Thus from the available bathymetric data for Indiana and Wisconsin
it is apparent that the cisco prefers to live in the deep, cold water of the
inland lakes. Where oxygen concentrations are adequate, as in Trout and
Clear Lakes in Wisconsin, the fish continue to occupy the entire hypolimnion throughout the summer, or only the bottom half of the hypolimnion in Green Lake. As the oxygen content of the lower hypolimnion declines, the fish are forced into progressively higher levels with the advancing season, as in Silver Lake (Wisconsin) and perhaps Oliver Lake.
With still further utilization of oxygen, the fish become concentrated
immediately below the thermocline, as in Lake Nipissing. The negative
response to the thermocline is very strong, however, and the fish stay
out of this stratum if possible. Nevertheless, in instances of extreme
stratification the ciscoes do enter the thermocline and may even live in
the upper half of the thermocline in late summer, as in Indian Village,
Hindman, Myers, Mendota, and Allequash lakes. Here they come into
contact with various warm water species of fish. Although the cisco
avoids the warmer temperatures of the thermocline if possible, when
207
forced to live in this stratum, it can tolerate temperatures up to 19° or
even 20° C.
The requirements of the fish for dissolved oxygen are less well understood. The fish may be able to tolerate concentrations as low as 1.5
ppm., although it seems more likely that the level for sustained activity
of the larger fish at least is somewhat higher, possibly about 2.5 or
3 ppm. Almost nothing is known concerning the effect of the CO2-content
of the water on the respiratory process of the species ; that is, the same
concentration of dissolved oxygen may have different physiological values
at different concentrations of free CO,. Black, Fry, and Black (1954),
for example, have shown that all 16 species of freshwater fishes studied
require greater amounts of dissolved oxygen at high CO, tensions than at
low tensions.
COMPARISON OF TEMPERATURE AND OXYGEN STRATIFICATION IN LAKES
WITH AND WITHOUT CISCOES
During the summers of 1950 through 1953, Lake and Stream Survey
crews visited a total of 33 cisco lakes and 36 non-cisco lakes for the purpose of obtaining basic limnological data. Some of the lakes were visited
only once, others were visited several times, and a few have been studied
intensively for one to three summers. In addition there are stratification
data given by Birge and Juday (1911) and Scott (1916 and 1931) for a
number of Indiana lakes, so that in all temperature and oxygen data are
available for 37 lakes now or formerly containing ciscoes, and 53 lakes
without ciscoes in modern time.
Relatively few of these lakes have had hydrographic surveys made. In
the absence of such maps the Official Indiana Lake Guide (Gutermuth
1938) is the only ready source of approximate information as to the
areas and depths of the lakes. In general, the areas listed in the guide
are more reliable than the depths. Most of the non-cisco lakes visited
by the Survey crews were selected for study because the Lake Guide
includes them among the deeper lakes of the State. Many of them were
found to be much shallower than listed.
The surface areas and maximum known depths of these 90 lakes are
presented in Table 5. Lakes represented by hydrographic maps are designated by an asterisk, and the area and depth of these lakes are taken
from the maps. Areas of all other lakes have been taken from the Lake
Guide. The depths listed, however, are the maximum depths found by
the Lake and Stream Survey crews, or reported by Birge or Scott. They
thus represent depths known to occur, and are believed in most instances
to more closely approximate the actual maximum depths than do the
figures listed in the Lake Guide. Each series of lakes is arranged in
order of decreasing known depth.
It is apparent immediately that there is no relation between the maximum depth of a lake and the presence or absence of ciscoes. Deep lakes
may or may not have the species, and likewise shallow lakes. In fact, two
208
TABLE 5. Known maximum depths and actual or approximate areas of Indiana lakes for which
denotes hydrographic map available. Counties are
temperature and oxygen data are available.
designated by the first letter of their names: Fulton, Kosciusko, LaGrange, Marshall, Noble,
Steuben, Whitley.
Non-cisco lakes
Cisco lakes
Lake
County
*Tippecanoe
Crooked
Clear
*Oliver
*Snow
*James
Dallas
Fish
*Big Long
Big
*Shriner
*Cedar
*Gage
Lawrence
*Little Tippecanoe
*Round
Myers
Lake of the Woods
Knapp
McLish
Shock
*Secrist
Martin
*J imerson
Messick
South Twin
Royer
Eve
Whitmer
Big Turkey
Hackenberg
Little Otter
*Gordy
Long
Atwood
*Indian Village
Hindman
K
W
S
L
S
S
L
L
L
N
W
W
S
M
K
W
M
L
N
S
K
K
L
S
L
L
L
L
L
L
L
S
N
S
L
N
N
Max.
depth
( m.)
37.5
33
32
28.5
27.5
26
26
24.8
24.7
23.7
22.3
22.3
21.3
19.7
18.9
18.9
18.5
18.5
17.5
17.2
17
17
16.8
16.5
16.5
15
14
13.5
12.5
12.5
12
11.5
10.5
9.5
9
6.5
6
Area
(ha.)
286
77.7
310
145
120
534
107
32.8
148
80.5
48.6
58.3
132
24.7
108
53.0
34.8
51.4
31.2
6.1
4.0
40.1
6.1
82.2
22.3
47.3
21.9
6.1
87.0
182
15.0
?
11.5
38.0
63.2
2.0
6.1
Lake
Loon
*Adams
*Maxinkuckee
*George
*Winona
Olin
Pretty
Diamond
*Wawasee
*Crooked
*Dewart
*Yellow Creek
Goose
Hamilton
Balls
Round
Troy Cedar
Fox
Bear
*Webster
Little Long
Cook
*Manitou
Blue
Round
*Big Barbee
Waldron
Pleasant
Pretty
Thomas
*Chapman
Bixler
Latta
Black
North Twin
*Silver
Center
Hill
Pike
Golden
*Cline
Hog
Otter
*Shoe
Walters
Hollem
Hogback
Big Cedar
Stevens
Duley
*Weir
Center
Loon
County
W
L
M
S
K
L
L
N
K
S
K
K
W
S
S
N
W
S
N
K
N
M
F
W
S
K
N
S
M
M
K
N
N
W
L
S
K
K
K
S
L
S
S
K
S
M
S
L
K
N
L
S
S
Max.
depth
( m.)
29
28.5
26.5
25.3
24.4
24
23.5
23.5
23.5
23.1
23
22
21.5
20.7
20.5
19.5
18.5
17.5
17
15.8
15.5
15
14.9
14.5
14
14
13.5
12
12
12
11.9
11.5
11.5
11
11
11
10
9.5
9.5
9.5
9.2
9.0
9
9
8.5
8
8
8
6
6
5.8
5
4
Area
( ha.)
321
119
751
206
215
38.5
74.5
38.8
1200
325
145
57.7
35.6
309
31.6
33.6
38.1
57.5
50.2
237
25.9
23.1
289
95.5
6.1
92.3
80.1
19.4
34.4
2.0
168
45.3
14.2
8.5
53.0
37.9
48.2
23.9
74.5
47.8
8.0
35.6
58.3
16.0
15.0
8.1
50.6
43.7
5.7
10.1
2.4
14.6
57.1
209
of the shallowest studied (Indian Village and Hindman) harbor the
species.
In order to ascertain what general differences in summer oxygen content and temperature stratification might be present between the two
groups of lakes, certain more or less arbitrary physiological limits were
established for the cisco. The species was considered capable of surviving at any depth where the temperature was 20° C. or less and the oxygen
content was 3 ppm. or more. All lakes, except a few with a very pronounced minus-heterograde oxygen distribution (Tippecanoe and Martin), could then be divided into three bathymetric zones : a supra-cisco
layer (essentially the epilimnion) with adequate levels of dissolved oxygen, but with water temperatures above 20°; an infra-cisco layer with
suitable low temperatures, but with oxygen contents less than 3 ppm.;
and an intermediate cisco layer, varying greatly in thickness from one
lake to another and sometimes completely lacking, in which the temperature is less than 20° and the oxygen content greater than 3 ppm.
In Figures 2, 3, and 4, the thickness of these three layers and the
la
cc
<u_N
La-
o
rn
05
0
In n
0C ,4
1 ?1 0
0
1 ,
5•6
.
6
•,,,
g
z
-1
,I E
IT:Aj
0
z
<
w20.,
L.)
u
=_
2_i !2 '3'],.;
f,°
lax
2=2
5
10
15
20
25
a
.?,
.
,.„,
LI,..T!
E=g,gt
>_
a.
<,
-
1,,
30
r,g
3C
13
=
0 >.
Is
ONY
z
■sni.
o
;2 5.
Eiglj
''
LJ ;
..,
. „,
<
,E
>. 21 5.
=,,,iu?Ji 32i iii
5
10
15
THERMOCL1NE
ED
TEMP.
>ze
TEMP.
<2e; 0 2 >3 PPM.
E21 02 <3 PPM.
FIG. 2. Temperature-oxygen relations in known cisco lakes under conditions of maximum recorded summer stagnation. The middle stratum in solid black is by definition the cisco layer, with temperatures of 20° C. or less, and an oxygen content of
3 ppm. or greater.
•
•
cr
z
0 'I)
•
0
—
co
N _1
FIACKENBERG
210
0
•
CTI
z=
>
0 nj •
CC
—
co
,7)
..
-.
co
<V
ni
0
Z >.
. o .1)
—I
-J
Cti Oi
aN
0 ,n
I—
5
•
< CD
1
5
I0
15
I
THERMOCLINE
1 TEMP
20
>20°
11111 TEMP. <20% 0 2 >3 PPM.
EZI 0 2 <3 PPM.
25
FIG.
3. Temperature-oxygen relations under conditions of maximum recorded summer
stagnation in lakes reported to have ciscoes present but not actively fished. The
middle stratum in solid black is by definition the cisco layer, with temperatures
of 20° C. or less, and an oxygen content of 3 ppm. or greater.
mean oxygen content within each layer is shown for each lake. Figure 2
is for lakes known to contain ciscoes, Figure 3 for lakes reported to now
contain ciscoes but not fished or to formerly have contained the species,
and Figure 4 is for lakes in which the cisco is not reported to be present.
Where several series of observations are available, the series with the
greatest depletion of oxygen in the hypolimnion was selected as representing the most extreme conditions of survival for the cisco. The heavy line
to the left of each figure shows the vertical extent of the thermocline, as
defined by a thermal gradient equal to or greater than 1° C. per meter.
The differences in temperature-oxygen relationships between lakes
containing cisco populations that are being actively fished and those in
which the cisco is not reported to occur are striking and quite consistent.
The stratum of water having conditions suitable for the species as here
defined tends to be thicker in the cisco lakes and also to have a higher
mean content of dissolved oxygen. Many of the non-cisco lakes do not
have any stratum suitable for ciscoes according to the arbitrary limits
established, and many others have only a thin cisco layer.
The diagrams for the individual lakes cannot be regarded as absolute
expressions of the stratification in the lakes, because there can be considerable variation from one year to another. For one lake the vertical
series available may approximate the extremes of oxygen utilization,
whereas in another lake the oxygen utilization represented may be even
less than average. The survival of ciscoes in a lake is necessarily con-
211
2
12
2;
42 o o 02.
Erg
E,5
10
20
23
la
■-•'
o-
6;
_ 60' , E.
2
.5>
3rvi
10
15
21
l k-13
II
0369
PPM 0 2
1[1] I
I
I
THE RMOC LINE
TEMP. >2ð
TEMP.
<20., 02 >3 PPM
1ESa 02 < 3 PPM
Fie. 4. Temperature-oxygen relations under conditions of maximum recorded summer
stagnation in lakes not reported to have ciscoes in them. The middle stratum in
solid black is by definition the cisco layer, with temperatures of 20° C. or less, and
an oxygen content of 3 ppm. or greater.
trolled by the extreme and not the average conditions. Hence, on the
basis of the single series of observations plotted one might wonder how
ciscoes can maintain themselves in Royer Lake, or why for example they
are not present in Olin or Fox lakes. Perhaps they are present in the
latter lakes, even though the fishermen did not report them. Olin Lake,
for instance, is closely connected to Oliver Lake and might be expected to
receive stock from this lake. In any event, the data show that the lakes
containing ciscoes have on the whole a greater buffer capacity against
extreme oxygen utilization than do the lakes without this species. The
loss of this margin of safety may well have resulted in the elimination
of the species from the latter lakes during extreme years, as conjectured
on p. 198.
The final critical limits and associated conditions that result in the
extinction of a cisco population in a particular lake are not known. Very
likely some individuals are able to survive at oxygen concentrations considerably less than 3 ppm. in extreme years. In Lake Mendota, Wiscon-
212
sin, for example, on Aug. 24, 1906, no stratum of water at temperatures
below 20° had an oxygen content as great as 3 ppm. (Birge and Juday
1911) . The same was true on July 26, 1951, in Hackenberg Lake, which
is reported to have a non-fished population of ciscoes.
TYPES OF OXYGEN DISTRIBUTION IN CISCO AND NON-CISCO LAKES
The main controls of the oxygen distribution in a lake are the depth of
the photosynthetic zone, the intensity of oxygen utilization in the deeper
water, and the stability of thermal stratification. Lakes having a large
volume of hypolimnial oxygen in relation to the amount utilized during
the summer tend to have an ortho grade distribution. Conversely, lakes
having only a relatively small volume of hypolimnial oxygen develop a
clino grade distribution. Where the transparency of the water is sufficient
so that at least the upper part of the thermocline is included in the photosynthetic zone, a plus-hetero grade distribution can develop. And finally,
in instances where a net positive assimilation does not extend to the thermocline, and where perhaps the thermal gradient is particularly steep, an
oxygen notch ( minus-heterograde distribution) can develop. This last
type of oxygen distribution is probably the least well understood.
Constancy of Oxygen Typology During a Given Summer
The stability or instability of these types during a single season is
illustrated by the detailed studies on temperature and oxygen distribution
made on Oliver, Myers, and Little Tippecanoe lakes in the summer of
1952. The bathymetric distribution of the cisco in Oliver and Myers
Lakes during 1952 has already been described. In Figures 5, 6, and 7, the
oxygen curves are shown chronologically, and in each curve the solid line
represents the "cisco layer" with a temperature below 20° C. and an oxygen content of 3 ppm. or greater. The limits of the thermocline at the
beginning and end of the period of observation for each lake are given to
enable the oxygen curve and the location of the cisco layer to be related
to the thermal gradient.
Oliver Lake
Oliver Lake (Fig. 5) had a plus-heterograde oxygen distribution during July and August, with the maximum gradually descending from 6 m.
to 8 m. below the surface. On Aug. 22 the maximum was barely discernible, and the distribution on this date might be classified as b-orthograde
because of the gradual decline in oxygen content nearly to the bottom.
Except for a thin stratum on July 21, an oxygen content exceeding 3 ppm.
extended all the way to the bottom of the lake until Aug. 22. Even by
Sept. 12, however, only the lowermost 3 m. had an oxygen content of
less than 3 ppm.
In 1953 Oliver Lake also had a plus-heterograde distribution on July 8,
which had changed to a b-orthograde (or a very weak plus-heterograde)
213
0
Cu
>—
27.0°
I
20.9°
thermocline
10
°
Sept. 12
—
8.4
15
20
38 2.4
25
3.0
38
'
1. 2
.3
1.0
OLIVER LAKE — 1952
4.1
0
,
.
ppm. oxygen
FIG. 5. Oxygen distribution in Oliver Lake during the summer of 1952.
distribution by Aug. 25. On the latter date the stratum from 7.1 to 20.8
m. had conditions suitable for ciscoes, comparing favorably with 1952.
On Sept. 6, 1930 (Scott 1931), the oxygen distribution present might be
classified as weakly clinograde, with the cisco layer occurring from 6.5 to
17.0 m. On July 26, the only analysis in 1951, the oxygen distribution was
minus-heterograde, and in late August, 1950, weakly clinograde. Hence,
the type of oxygen distribution not only can vary within a single season,
but can also vary from one year to another, depending upon the several
factors controlling the bathymetric production and consumption of oxygen. As a consequence, the thickness of the zone habitable by ciscoes can
also vary from month to month and from year to year. The "oxygen
buffer capacity" of a lake is therefore important in helping the ciscoes
survive through seasons of extreme oxygen utilization. Oliver Lake
consistently has one of the most adequate oxygen supplies known for Indiana lakes, in spite of these variations in the type of oxygen distribution.
Myers Lake
Of all the lakes for which data are available, Myers Lake has the most
pronounced plus-heterograde distribution. As evident in Figure 6, an
oxygen maximum in the lower half of the thermocline was already well
developed on June 26, and this prominent maximum persisted to at least
Sept. 11. These rough data suggest that there were two peaks of photosynthesis at 8 m., one in late July and the other in late August. The cutoff in dissolved oxygen at times was very rapid below the photosynthetic
to
to
I- I0_ ..°2
Li
N
).-
>-
)-
...1
D
1
-I
D
n
g
25.4°
CO
N
0
)-
Li
D
J
<
,
0
CO
N N
N
Li
Li
D
<
6
< <
=
I-:
0.
IJ
CI)
/
1 21.7 °
therrnochne
thermocline
June 26
18.5
17.1
10
1 8.5
20.
19.8
16.7
1 6.4
Sept. 11
..... .....
7.5°
8.3*
..
0
15
MYERS LAKE — 1952
FIG.
6.
Oxygen distribution in Myers Lake during the summer of 1952.
ppm. oxygen
215
maximum, with the result that there was usually virtually no oxygen
below a depth of 10 or 11 m. The ciscoes at this time were necessarily
living in the thermocline, and this is where they were caught with gill
nets (see discussion on bathymetric distribution) .
Not only did the plus-heterograde distribution in Myers Lake persist
throughout the period of summer stratification, but it is also developed
each year to about the same extent. A plus-heterograde distribution
was observed on all occasions during the summers of 1951 through 1954.
The factors involved in the development and maintenance of an oxygen
maximum are not yet too well understood, but the consistent development
of such a maximum is believed to be of very great importance in enabling
the survival of cisco populations in some of the smaller lakes of the State.
Little Tippecanoe Lake
Little Tippecanoe (Fig. 7) is representative of a small number of cisco
lakes and of the bulk of the non-cisco lakes with its clinograde oxygen
distribution. The lake develops a very pronounced oxygen deficit in the
hypolimnion. In middle August of 1952 there was very little oxygen below a depth of 7 m. The situation improved somewhat in late August and
early September, although still not sufficiently to permit the survival of
ciscoes below a depth of 7 m. Early in the summer the lake had a rather
sharp oxygen maximum in the upper part of the thermocline, but this
was completely dispelled within a space of only two weeks.
Conditions such as occur in Little Tippecanoe very likely approach the
extreme conditions that the species can tolerate. Even the shallower
lakes of the Indian Village chain in Noble County do not confront the
species with such severe demands for survival. On the basis of the arbitrary definition set up in this paper, the cisco layer in Little Tippecanoe
was compressed by warm temperatures above and oxygen utilization
below to a stratum only 0.1 m. thick on Aug. 11, and 0.2 m. thick on
Aug. 18. One wonders how the species can possibly survive under such
extreme conditions of stratification.
Six fishermen contacted in the questionnaire reported that they have
fished for ciscoes in Little Tippecanoe during the spawning season in
late November and early December. In 1952 the Lake and Stream Survey crew fished the lake with four experimental gill nets during the
periods July 8-10, and Aug. 5-9. Bottom sets were made in water depths
from 1.6 to 12.5 m., and diagonal sets were made from the surface to the
bottom in water as deep as 10.6 m. The 'nets were certainly fished at all
possible depths at which ciscoes might have been present. Yet not a
single cisco was taken in the ten times the nets were lifted. Other
species, however, were caught in or just above the cisco layer. One
rockbass and one warmouth bass were caught at 5.8 m. Another warmouth was caught at 4.9 m., and five white suckers were caught at 5.2 m.
Specimens of these and other species were taken quite commonly in still
shallower water.
-JUNE 28
,r)
>-
>-
D
—)
.
.
D
D
D D D
< < <
.".
..."
,
25.9 °
:
...........
5
thermoc line
........
.....
June 28
10
LI
(/)
.......
...
..•• .........
20.7 °
.....
..
thermodline
r ...
Sept. 8
8.8°
8.3°
15
0.2
0.2
20
0.1
0.2
O. 02
0
0
5
ppm. oxygen
LITTLE TIPPECANOE LAKE -
1952
Fro. 7. Oxygen distribution in Little Tippecanoe Lake during the summer of 1952.
217
What is not known is if the fish caught in Little Tippecanoe in late
autumn have spent the summer in the lake. There is a possibility that
they may have come from Big Tippecanoe, because Jordan (1875a)
quoted the observations of Judge J. H. Carpenter that at spawning time
the ciscoes "come in myriads into the streams which enter the lakes."
Cahn (1927) also noted that ciscoes may ascend streams at spawning
time and actually spawn in the rivers. As a specific example, some fish
ascend the Oconomowoc River from Fowler Lake, even though the majority of the population spawns in the lake. It is difficult to understand,
however, how such a "run" from Big Tippecanoe into Little Tippecanoe
could maintain itself, because if the mid-summer oxygen conditions are
inadequate for the survival of the species, then any fingerlings developing from the eggs spawned in the lake would be doomed to early death.
On the other hand, the fish might return to Big Tippecanoe Lake in spring
before the unfavorable oxygen stratification develops. Kennedy (1941),
for example, found that a number of species, including the closely related
whitefish (Coregonus clupeaformis), moved in spring from the relatively
shallow White Lake into the considerably deeper Big Trout Lake. The
movement was believed to be induced by the warmer temperatures in
White Lake. It is interesting that the largest individuals migrated first,
a pattern similar to that observed by Fry (1937) for the downward
spring movement of the cisco in Lake Nipissing.
James Lake
A further example of the oxygen and temperature distribution in
cisco lakes, emphasizing this time the differences that can develop from
one year to another, is afforded by James Lake (Fig. 8). On Sept. 20,
1930, the oxygen distribution was minus-heterograde, with only a trace
of oxygen at a depth of 24.5 m. On Aug. 21, 1953, the distribution was
plus-heterograde, and on Aug. 5, 1951, essentially b-orthograde. The
vertical extent of the cisco layer is indicated by the solid portion of the
oxygen curve. At no time was the temperature-oxygen distribution critical for the species, unless individuals were trapped below the oxygen
notch on September 20, in the manner Scott (1931) postulated for Snow
Lake.
Thus, although probably all temperate holomictic lakes have an orthograde oxygen distribution during the spring overturn, relatively few of
them are able to maintain this distribution over the summer. The most
common condition in shallow stratified lakes is for a clinograde distribution to develop, either directly or after first passing through one of the
heterograde types. A plus-heterograde distribution, especially when it is
maintained throughout the summer, appears to offer the most favorable
situation for maintaining the cisco in shallow lakes.
Oxygen Type-Frequency Distribution
In order to determine if there are any significant differences in the
218
ppm. oxygen
temperature
2 4 6 8 10
8
°
C.
16
24
DEPTH—meters
5
10
15
20.IX.30
21.V111.53
20
25
MINUS
HETEROGRADE
PLUS
HETEROGRADE
B -ORTHOGRADE
LAKE JAMES - 3RD BASIN
FIG. 8.
Oxygen curves for James Lake in three different years, showing the variation
in type of oxygen distribution that can develop from one year to another. The solid
portion of the oxygen curves designates the stratum with a temperature below
20° C. and an oxygen content greater than 3 ppm.
oxygen distribution of cisco lakes as compared with non-cisco lakes, a
type-frequency distribution was prepared for each lake, based on all the
years for which chemical data are available. These data are presented
in Tables 6 and 7. In each table the lakes are arranged in order of decreasing depth to take account of the fact that in small lakes the thermocline generally lies closer to the surface than in large lakes. With the
same transparency, therefore, small lakes theoretically are more likely to
have a photosynthetic maximum of oxygen in their thermocline than
large lakes. The mean depth of the thermocline is listed for each lake.
Even a superficial comparison of the tables shows that there is indeed
a significant difference in the oxygen distribution between the cisco and
non-cisco lakes, and this is particularly true for the smaller lakes. Although a number of the cisco lakes exhibit a clinograde distribution, much
more frequently they have a plus-heterograde distribution, and somewhat
less frequently a minus-heterograde distribution. The majority of the
cisco lakes less than 60 ha. in surface area regularly have an oxygen
maximum in the cold water of the thermocline. The author believes that
this factor is largely responsible for the survival of the cisco in lakes
219
TABLE
6. Frequency of types of oxygen distribution in the cisco lakes of Indiana.
Counties are designated by the first letters of their names.
Frequency of 0, types
Lake
County
Area
(ha.)
No. of
years
I. Lakes with cisco populations that are fished.
6
S
534
James
5
310
Clear
S
286
4
K
Tippecanoe
5
L
145
Oliver
132
5
S
Gage
5
S
120
Snow
2
108
Little Tippecanoe K
2
L
107
Dallas
77.7
4
W
Crooked
58.3
2
w
Cedar
51.4
1
Lake of the Woods L
2
48.6
Shriner
W
1
L
47.3
South Twin
Secrist
Myers
Fish
Knapp
Lawrence
Royer
Gordy
McLish
Martin
Eve
Hindman
Shock
Indian Village
K
M
L
N
M
L
N
S
L
L
N
K
N
40.1
34.8
32.8
31.2
24.7
21.9
11.5
6.1
6.1
6.1
6.1
4.0
2.0
1
4
1
3
1
1
3
2
1
2
2
2
3
Mean
depth of
thermocline
(en.)
5.7-10.7
6.6-11.2
5.7- 9.7
5.4-10.7
5.9-10.5
5.2- 9.4
4.5- 9.5
5.5- 8.5
4.8-10.5
3.5- 9.5
4-9
4-9.5
6-11
4-8.5
4-10.5
4-8
3.3-7.3
3-9
3-7
3.3-7.7
3.5-8.5
2-7
4-9
2-5.5
2-7.5
2-6.3
borthograde
plusheterograde
2
1
4
minusheterograde
2
4
1
2
2
3
clinograde
1
1
2
3
2
2
2
2
2
1
2
1
1
4
1
2
1
1
1
1
2
2
1
2
2
2
1
2
II. Lakes reported to have ciscoes now (although not fished), or to have had ciscoes
formerly.
Big Turkey
L
182
1
4-8
1
Big Long
L
2
5-10
1
1
148
Whitmer
Jimerson
L
Big
Atwood
Round
Long
Messick
N
L
W
S
L
L
Hackenberg
s
87.0
82.2
80.5
63.2
53.0
38.0
22.3
15.0
1
2
2
1
2
1
1
1
4-9
4.5-8.7
4.5-8
5-9
4.5-10
2-7
3-9
0-8
1
2
2
1
1
1
1
1
1
as small as these.
Even quite a number Of the larger lakes have a plus-heterograde distribution. Almost equally common among these larger, and for the most
part deep, lakes, however, is a minus-heterograde distribution. If the
oxygen notch results from the decomposition of current organic product
arrested in its rate of sinking by the sharply increasing viscosity and
density associated with a particularly steep thermal gradient, then the
220
TABLE 7.
Frequency of types of oxygen distribution in the non-cisco lakes of Indiana.
Counties are designated by the first letters of their names.
Frequency of 02 types
Lake
Wawasee
Maxinkuckee
Crooked
Loon
Hamilton
Manitou
Webster
Winona
George
Chapman
Dewart
Adams
Blue
Big Barbee
Waldron
Pretty
Pike
Otter
Yellow Creek
Fox
North Twin
Hogback
Bear
Center
Golden
Bixler
Diamond
Olin
Troy Cedar
Silver
Goose
Hog
Pretty
Round
Balls
Little Long
Hill
Cook
Pleasant
Shoe
Walters
Center
Latta
Duley
Black
Hollem
Cline
Round
Stevens
Weir
Thomas
County
K
M
S
W
S
F
K
K
S
K
K
L
W
K
N
L
K
S
K
S
L
S
N
K
S
N
N
L
W
S
W
S
M
N
S
N
K
M
S
K
S
S
N
N
W
M
L
S
K
L
M
Area
(ha.)
1200
751
325
321
309
289
237
215
206
168
145
115
95.5
92.3
80.1
74.5
74.5
58.3
57.7
57.5
53.0
50.6
50.2
48.2
47.8
45.3
38.8
38.5
38.1
37.9
35.6
35.6
34.4
33.6
31.6
25.9
23.9
23.1
19.4
16.0
15.0
14.6
14.2
10.1
8.5
8.1
8.0
6.1
5.7
2.4
2.0
No. of
years
Mean
depth of
thermocline
(in.)
1
2
2
2
2
1
1
2
1
1
1
4
1
1
1
4
2
1
3
1
1
1
1
3
1
1
2
1
1
1
2
1
2
2
2
1
1
2
2
1
1
1
1
2
1
2
1
3
1
1
1
9-12
7-10
6-10.5
3-7.5
5-9.5
3-8
4-9
5.5-10
5-10
C-10
6-11
5.8-10
6-9
3-8
4-8
5.3-10.1
3-7
3-9
3.3-8.7
3-9
5-11
3-6
4-8
4-8.3
3-8
4-9
4-9.5
4-9
3-8
4-10
3-7.5
3-9
4-8
4.5-9.5
4-9.3
5-9
5-9.5
4.8-9.8
5.5-10
4-8
2-6
3-5
5-9.5
2-6
2-7
4-8
4-9
4.3-10
2-6
4-5.5
1-7
b°mho.
grade
plusheterograde
minus.
hetero.
grade
1
2
1
1
1
1
1
1
2
1
2
1
1
1
1
1
3
1
1
1
3
2
1
3
1
1
1
3
1
1
2
1
1
1
2
1
2
1
2
2
1
1
1
2
1
1
1
1
1
clinograde
1
2
1
2
1
1
1
1
1
Note: Loon Lake (Steuben, 57.1 ha.) and Big Cedar Lake (LaGrange, 43.7 ha.)
are 3rd order lakes with no water as cold as 20° C.
221
oxygen notch can be looked upon as a conserver of hypolimnial oxygen.
The presence of an oxygen notch would then mean that the levels of
oxygen in the hypolimnion are higher than they would be without such
a notch, particularly if it is true that the hypolimnial oxygen deficit developing in a given year is more closely controlled by the production of
that year than by the accumulated organics of past years in the uppermost
sediments. Einsele (1941) concluded this was true for Schleinsee and
probably also for all other lakes in which allochthonous organic matter is
at a minimum.
A clinograde distribution is developed primarily in the deepest cisco
lakes. In many of these, such as James, Clear, and Oliver, the clinograde
distribution is only weakly developed, being somewhat intermediate between the clinograde type (sens. str.) and the b-orthograde type. It is
interesting that in the smallest cisco lake known, Indian Village Lake, the
oxygen distribution in two of three years was clinograde, rather than
plus-heterograde, as in the other small cisco lakes. Hence, a plus-heterograde distribution is not an absolute sine qua non for the survival of the
cisco in small lakes.
The non-cisco lakes are quite uniformly clinograde, usually strongly
so. A few were weakly plus-heterograde in one or two years. Adams and
Pretty lakes in LaGrange Co. were each plus-heterograde in only one of
four years. This condition was associated with a somewhat thicker stratum habitable by ciscoes. The plus-heterograde condition listed for Fox
Lake was observed on July 10, and for Hog Lake on July 23. It is not
known if this condition persisted through August into the partial fall
overturn, although this is likely for Fox Lake, because the oxygen maximum here was strongly developed. Olin, Pretty (Marshall Co.), and
Latta lakes seem to be suitable for ciscoes if the weakly plus-heterograde
condition observed in them develops regularly each year, as it may well
do in Pretty Lake. Aside from these few lakes and Manitou, which although clinograde still had a fair amount of oxygen in deep water in the
single year examined, there are no lakes included in this study which very
likely contain cisco populations even though not reported by the fishermen. Thus, the oxygen-temperature stratification in the various lakes
attests to the general reliability of the questionnaire reports by the
fishermen.
•
Relation of Oxygen Typology to Summer Surfacing and Mortality
Scott (1931) was particularly interested in Snow Lake because the
ciscoes there are reported to surface early in September in almost every
year. He postulated that the fish become trapped in the oxygenated layer
below the oxygen notch, and that, as the oxygen content of this lower
layer is still further used up, the fish, unable to tolerate the conditions
any longer, undergo temporary asphyxiation and rise to the surface. Scott
did not believe that these fish died, but rather that after adjusting
physiologically to the new conditions, they remained in the epilimnion
222
until fall turnover.
Scott diagrammed the oxygen distribution in Snow Lake on Sept. 14,
1929, and Sept. 7, 1930, to illustrate his point. On the former date there
was no oxygen below a depth of 9 m., except for a trace of about 0.15
ppm. at 12 m. According to the opinion of the present paper the ciscoes
would have been eliminated from the hypolimnion long prior to this time.
On Aug. 9, the last date in 1929 for which data are tabulated, there is no
suggestion of a minus-heterograde distribution. Likewise, on Sept. 7,
1930, there is a very minor nick in the oxygen curve at 11 m. amounting
to only 0.43 ppm. (not even listed in the table for this date), and in the
other August and September series for this year (except possibly Sept. 2)
there is no trace of an oxygen notch. The oxygen distributions might best
be classified as clinograde, or even weakly plus-heterograde because of
the slight yet distinct increase in oxygen content from the surface down
to depths of 7 and 6 m., respectively, in the two years. In neither year
does the very weak oxygen notch in September represent, therefore, a
final stage of a persistent minus-heterograde oxygen distribution. The
data presented by Scott do not seem to support the theory he developed.
The cisco fishermen reported similar early September surfacing of
the species (with mortality) to occur irregularly in Tippecanoe, Crooked
( Whitley Co.), James, Jimerson, Snow, Clear, Lake of the Woods, Dallas,
Little Tippecanoe, McLish, and even Myers lakes. More fishermen did
report them surfacing in Snow Lake than any of the others, however. A
number of specific instances are : Tippecanoe in 1949, 1950, and 1954;
Clear Lake on Labor Day a few years ago ; Little Tippecanoe in 1948;
Snow Lake in 1947 and 1948; Dallas Lake in August of one year ; Myers
Lake in 1953; etc. The point is that many of these lakes according to
the data available do not develop a minus-heterograde distribution. Tippecanoe Lake, which has the most pronounced minus-heterograde oxygen
distribution known from Indiana lakes, represents the only lake that
might correspond in fact with Scott's theory to explain late summer surfacing and mortality. Hence, regardless of how reasonable the theory
seems to be, there are no satisfactory data from Snow Lake or elsewhere
to support it. The oxygen notches in Snow Lake considered by Scott do
not seem to have much real physiological significance for the species, and
September surfacing (and mortality) of the cisco occurs in quite a number
of Indiana lakes representing a variety of types of oxygen distribution.
DISCUSSION AND CONCLUSIONS
The coregonids as a group are generally considered to be polyoxybiontic cold stenotherms, primarily boreal in distribution. The cisco of
North America and its European counterpart (C. albula) conform less
closely to this generalization than any other species reported on in the
literature, although probably the young of all species are less demanding
in their environmental requirements than the adults. Contrary to the
belief prevalent among limnologists and fishery biologists, the cisco is
223
not restricted in its distribution to cold water with high levels of dissolved oxygen. The species obviously is as plastic physiologically as it is
morphologically, and, particularly among residual 200)
populations, its toleraand of fairly low
tion of fairly high temperatures (up to perhaps
levels of dissolved oxygen (certainly down to 3 ppm., and possibly even
lower) is well documented by both the present and a number of previous
studies.
In our inland lakes the cisco spawns in shallow water in NovemberDecember when the water temperature has dropped to slightly below 4°
C. (Cahn 1927) . During the winter the fish are apparently generally distributed through the lake, occurring abundantly towards the surface. As
the water warms in spring the fish begin to migrate from the surface
water into the colder water below the incipient thermocline. In Lake
Nipissing (Fry 1937) at least, the entire population does not migrate
downward at the same time, but rather the migration occurs in a quite
orderly sequence according to size and sex. The largest individuals of
either sex migrate earliest, with the males of a particular size moving in
general before the females. The two youngest age groups move downward last. Once the fish get into the deep water in this lake and in
other cisco lakes, they tend to remain there until the time of the fall
partial overturn, or even until the complete overturn.
In any given lake the species tends to occur in the coldest water having
adequate levels of dissolved oxygen. When high levels of oxygen are
available, the summer bathymetric distribution may in some instances
involve only the lowermost part of the hypolimnion and in others the entire hypolimnion. As the lake ages typologically and the oxygen content
of the hypolimnion gradually declines, the fish are forced progressively
higher in the hypolimnion. The steep temperature gradient of the thermocline, however, constitutes a formidable block to further upward displacement, and apparently only under conditions of extreme oxygen deficit in the hypolimnion does the species penetrate the overlying stratum
of rapidly changing temperature. A number of instances are known
based in part upon the presumed tolerance limits of the species to temperature and oxygen, where the fish do live in the thermocline in summer,
and even in the upper part of the thermocline.
The most extreme conditions of survival occur in those lakes where
during the height of summer stagnation there is no stratum in the lake
with a temperature less than 20° C. and an oxygen content as great as 3,
or even 2, ppm. Even under these extreme conditions, however, the fish
still react negatively to high temperatures. The epilimnion-thermocline
junction in Indiana lakes usually has a temperature in the neighborhood
of 20°. Towards the surface temperatures are higher. The downward
transport of oxygen by turbulent diffusion and by more general circulation is such that in all lakes known to contain ciscoes this boundary
stratum has adequate levels of dissolved oxygen for the species. Possibly
the cisco, particularly the young of the year, can actually survive over
224
extreme summers in a thin stratum above the thermocline, as defined
by Birge, although beyond this the species even with its great physiological adaptability cannot go. There are no known lakes in Indiana or elsewhere in which adult ciscoes are generally distributed through
the epi0
limnion in summer when the water temperatures are above 20 .
At some point in the aging of a lake the tolerance limit is surpassed,
and the local population is snuffed out. Probably long before this time
is reached the population has become greatly reduced in numbers, and significant reproduction occurs only at relatively infrequent intervals. Such
a residual population with an atypical age structure, including the complete absence of one or more of the younger age groups, would be expected to be less capable of surviving a period of unusually extreme
thermal and chemical stratification than a more normal population.
Cisco populations in northern Indiana are not confined to the largest
and deepest lakes ; indeed, four of the cisco lakes have a known maximum
depth of less than 10 m. Indian Village and Hindman lakes with miximum depths of 6.5 and 6 m., respectively, are the shallowest known cisco
lakes.
It is not believed, however, that the populations in these and many
other of the shallower cisco lakes are existing under the most extreme
conditions the species can endure, because there is a tendency in the
shallower cisco lakes in particular for significant photosynthesis to occur
in the region of the thermocline during summer, thereby providing adequate levels of dissolved oxygen at fairly low water temperatures. This
factor is believed to be of importance in maintaining the species in many
of the shallower lakes. The most extreme conditions are believed rather
to occur in those lakes that exhibit a steadily declining oxygen content
below the epilimnion. In these lakes the hypolimnion and even much of
the thermocline can be completely lacking in oxygen or have only very
low levels remaining by the height of summer stagnation. In a number
of such lakes represented in this report, both in Indiana and Wisconsin,
there was on occasion in summer no stratum of water with a temperature
less than 20° C. and an oxygen content as great as 3 ppm.
Assuming that all the natural lakes in the region concerned in this report either actually contained ciscoes or were accessible to colonization
by the species in early post-Cary time, regardless of whether the particular lakes were ultimately located in the Great Lakes or the Mississippi
River drainage basin, then those lakes still containing ciscoes represent
the only ones in which conditions within the tolerance range of the species
have persisted during the intervening millenia. The interesting fact regarding the distribution of cisco lakes in Indiana is that the lakes are not
randomly distributed through the lake district but are grouped together
in definite clusters, suggesting that particular patterns of geologic and
geomorphic factors constitute the chief controls in their distribution.
Through the action of these regional factors the cisco lakes tend to have
a greater buffer capacity or safety factor for the cisco regarding oxygen
225
depletion in cold water, and also to have a more frequent positive assimilation balance in the thermocline in summer, resulting in higher levels of
oxygen here than would otherwise occur. Dr. W. J. Wayne of the Indiana
Geological Survey has suggested that the clusters of cisco lakes tend to
be located in regions of glacial outwash rather than of till. The surrounding surficial material would therefore tend to be size sorted, probably
with a greater permeability and a relatively smaller percentage of very
fine particles. The manner in which these factors, or others associated
with them, might influence the development of the oxygen stratification
described in this paper is not yet comprehended.
Thienemann (1950) believes that the European equivalent (Coregonus albula L.) of the North American cisco originally fed on benthos, but
that as the oxygen content of the hypolimnion declined it was forced upward away from the bottom, and consequently had to modify its feeding
habits. The fine gill rakers preadapted the species for feeding on
zooplankton. In the oligotrophic lakes where there is adequate oxygen in
the deep water but little plankton the present plankton-feeding species
does not do very well. In the strongly eutrophic lakes where there is insufficient oxygen for the species in deep water, the surface waters even
though containing adequate oxygen and an abundance of zooplankton are
either so warm that the species has been eliminated altogether, or else the
populations are very small and marginal. At the intermediate mesotrophic stage of lake development a large zooplankton occurs along with
adequate oxygen in the upper hypolimnion, and it is in such lakes that
the populations tend to be densest and most successful. The same limnogenetic controls are claimed to operate for the stint (Osmerus eperlanus
L.) in the north German lakes.
Certainly of all the coregonids in North America the cisco is best able
to maintain itself under conditions of relatively high temperature and
relatively low oxygen. During the gradual typological aging of a lake
the cisco population probably alters its physiology correspondingly. If
the matter were properly studied we would surely find the populations
in different lakes to be as variable physiologically as they are morphometrically. Moreover, a considerable part of this variability might well
be the same kind of direct and short-term response or adaptation to environmental conditions that Hile (1936b, 1937) discovered for the morphometry of the species in northern Wisconsin.
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