The Wilmington morning star., 1947-09-28
Counting Crackers Cause
Research Into Noises Made
Bv Fish In South Atlantic

k4lO 4ottS1 SAS
counting croakers.
As aresult of the April l, con-
ference in 1913, the Navy as
signed the studies on segregat-
ed fish to the Naval Ordnance
Laboratory and the measure
nent of the noise off Florida
was made a joint project for
the San Diego laboratory, the
New London laboratory, and the
Naval Ordnance labor atory.
Segration work was pur-
sued at the Shedd Aquarium of
Chicago and also at the U. S.
Fish and Wild Life Station on
Pivers Island between More
head City and Beaufort. A 80
foot yawl, the U. S. S. Saluda
was used for studies in the Gulf
Stream.
! The work on Pivers Island be-
gan in June 1943 and continued
through August. Efforts were
made to arrange conditions in
such a way that the fish, al
though segregated, would feel
more at home than in an aqua
rum.
DR.. H. F. Prytherch, director
of the laboratory on Pivers Is
land worked with the men who
set up the sound equipment for
recording the noises made by
various fishes.
A floating net for confinement
of certain species of fish with a
hydrophone suspended from
a corner Of the frame which
held the net was placed in a
section of the experimental fish
farm. Into this net, various spe.
cies of fish caught by CONNER
cial fishermen employed for the
purpose of supplying same, were
placed.
Definite recordings of the
sounds of many species were OBJ
tanned during the period that the
experiments were underway. Not
all of the recordings were made
from the sounds that came from
fish in the special net in the
"fish farm"
Eydrophones were suspended
from the bridge which connects
the island with the main high
way leading from Beaufort to
Morehead City and mere noises
Of other species we're detected.
A toadfish was captured and
placed in the special net, but
while a prisoner over a period
of one month it made no noise.
Then one day the hydrophone
was suspended from one of the
Pivers Island piers. A peculiar
noise was recorded it sounded
almost musical.
This noise continued to come
from the microphone for about
one week. = crab trap was low
cred with the hopes of captur-
ing the fish making the strange
noise. When the trap was down
the noise stopped. When it was
pulled up, a slimey and fat toad
fish was imprisoned in it. It was
kept in the experimental pond
for several days but never once
did it produce the musical note
or any sound for that matter.
Circumstantial evidence seemed
to indicate that the musical
sounds definitely came from the
toadfish which quit singing
once it was in captivity.
In ~ the crews of patrol boats
never reported any musical
sounds from toadfish. The noise
they heard came from croakers
counting croakers making love
to each other in the waters off
the Carolina Capes.
It will probably never be
known how much noisy fish ac-
tually interfere with acoustic
gear, but it is said that Jul sub
marines took advantage of crack
ling shrimp in the Pacific, hiding
under it's cover to evade enemy
echo-ranging gSr.
The experiments conducted al
Pivers island and elsewhere IN
connection with mostly fish, open
up possibilities with the aid {.
sound gear) in locating schoo.
of them and catching them COM
mercially in peacetime. It would
be helpful for fishermen to have
more than a mere "hunch" t.
tell them to lower their nets.