Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1870-10-12
On the Deep-Water Fauna Of Lake
MIchioan

Vh the Deep-Water Fauna Of LAX
Michigan.
FROM the American Naturalist
n knowledge OF the character of the an;
mais ana plants living at the bottom of tb,
great North American Lakes, the larges
BODIES OF fresh water in the world. ba,
long been desideratum; and dredgine
| operations have this year been initiated
by the Chicago Academy of sciences
which hsve already produced in
teresting re5albs. The first dredo
lngs were made OF Chicago, where
the waters were found TO be sbal
low, and the bottom sandy or grayeil7. Al
| a distance OF eighteen miles from land the
depth was but fourteen fathoms. The bot
tom was nearly barren of life. We obtain.
| ed, however, specimens of the larya OF
| some fsntoPterous insect, O Czepsi2p. q
flesh colored lee6h belonging to new se-
nus; Lynnoea. two Molsnians, and a
PietmateAo The plants consisted of a
moss, Chard, q Nostoc, and one other
alga,
Iho next Investigations were made in
the more GENITAL and deeper parts of the
lake. DR.. Hoy, of Raeine, had been for
some sin'e3 endeayoring to ascertain the
natuye OF tBe tood Of the w1iteash,
which had previously fenaaihed entirely
unknown. These fish being cajtga3 in gill
nets and pounds" are generally taken
from the water some hours after being &C,
tually entrapped, and the food in the
stomach becomes thoroughly aigested, and
it's Character undistinguishable, before it
can BE obtainea and examined DR.. How.
howeyefj aftef long search, succeeded in
obtaining some fish In which the Contents
of the stomach were III q som tsafativeiy
fresh state, and ascertained them 10 c6nssst
mainly of the remains of small crustaceans.
These he submitted to me for examina-
ton. a1d among them ! had the pleasure
of detecting fndicatieps of the existence of
maiina fotms IL the LAKE,
Il thus beGa19e hiahly desirable to ex
anime the ground upon which DR.. Hogs
fishes had been obtained, and accordingly,
on the Oath of June last. we started CIT
from Esc.ne for the purpose, in tug be-
longing % tbat place. The party con-
sisted OF Tr. ImpItam, DIR. HOY. Mr..
Blatchford, and br. Nndr8ss, of Chicago,
and myself. We dredged at SYaffoJis points
the greatest depth found being sixty
foGf. fathems, with bottom of
blacRish ln1plaosbis mud Between
the distances of twelve and twenty-five
miles frb5p shore, the depth was telerably
uniform, averaging forty-fve .fathonis; the
bottom being generally d faadisf OF brown
isb, sandy mud. On this plateau vs. OBJ
tanned alive the crustacea found by Dr.
hoy In the stomachs of the whitefsh, con-
sistipg Of a Mysis and two species of Gan
iniarus A small Ntite Planaria aud new
species Of Pisidiuni also occurred. All of
these sniniafs were found in abundaree,
showing this PORTION Of the lake bottom to
be rather densely Inhabited
Mysis is O marine genus, many species
of which occur in the colder parts of the
North Atlantic and in the Arctic seas One
species, NJ relcta, was found by Loven in
with idotheG entomon and other
marine efustasea IN tie deep fresh water
lakes, Wenner and Wetter, of Sweden, in
dlcatIng that these basins wefe formerly
filed with saltwater, and have been isolats
ed from the sea BY Che elevatory movement
of the Scandinavian petiinsuIa which
is still going on. That th5 same
thing has occurred to our own lakes
is shown by the occurrence in
their depths of the genus Mysis, notwith-
the non-eoncnrrence of marine
shells i'll the qtiaternarJ desposits on their
shores Kingston, On Lake Ontario, is, /
believe, the highest point in the valley at
which such shells have been found. Very
probably, at the time when the sea had ac-
cess to these basins the communication
was somewhat narrow and deep, and the
influx of fresh water from the SURROUNDING
country was sufficient to occupy entirely
the upper stratum, while the heavier sea- wa
ter remained at the bottom. After the
basins had become separated from the
nv VIC of thn he ton
water must have become fresh, by diffu-
sion, very slowly to allow of the gradual
adaptation of the crustaceans to the change
of element Possibly the occurrence at the
bottom of salt springs, like those Of the ad-
jacent shores OF Michigan, may have had
something to do with the slowness of the
change. At present, the bottom water,
Judging from specimen we obtained at a
depth OF tiftv-ive fathoms approximately,
is entirely fresh.
[ am informed, by Professor Gill that the
1Tiglopsis Thonaps0nii of Girard, is Z ma
rIne, rather than q fresh water form. This
fish inhabits the depths of the lakes, hav-
ing been found by Profussor, Baird in the
stomach OF b0ta mGculOsd, taken 10 Lake
Ontario, and recently by DIR. Hoy, In those
Of trout caught off Racine:
Our Mysis is allied to certain arctic
forms which would lead us to refer its orig
inal entry into the lakes to the cold period
of the quarterly epoch. While the marine
species usually live near the surface of the
water, this one appears to be confined to
the bottom, 8. result Of it's seeking the
colder and at former time more saline
waters.
The investigation of the materials OBJ
taiued by the dredging parties of the Acad-
will be published in fill with illustrations
at an early day.