Download Translation Series No.1358

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FISHERIES RESEARCH BOARD OF CANADA
Translation Series No. 1358
THE EFFECT OF SOUND AND OF ELECTROMAGNETIC FIELDS
ON THE BEHAVIOUR OFCASPIAN KILKA
.
By I. V. Nikonorov and A. Kh. Pateev
Original title: Vliyanie zvukovogo i elektromagnitnogo polei
na povedenie Kaspiiskoi
From: Rybnoe Khozyaistvo, Vol. 44, No. 9, p. 11-12, 1968.
Preliminary translation by W. E. Ricker
Fisheries Research Board of Canada
Biological Station, Nanaimo, B. C.
•1
1970
This is a preliminary translation prepared for the use of
Fisheries
the
Research Board of Canada. It is not a definitive
English version of the article, and it has not been checked or
approved by the author.
The effect of sound and of electromagnetic fields
on the behaviour of Caspian kilka
By I. V. Nikonorov and A. Kh..Pateev-
In searching for new stimuli that might be used to
help catch fish or to increase the effectiveness of present
fishing gear, we have investigated the effect of sound, ultrasound and electromagnetic fields on the behaviour of kilka.
Observations were made in May on the Caspian Sea in the
region of the kilka fishery, on board a ship at night during
quiet weather. The anchovy kilka (Clupeonella engrauliformis)
was used in the experiments; they , were obtained from catches
made at the light of a cone net. The kilka were placed in a
thick-walled aquarium made of rubber, 2000 x 1600 x 500 mm.
The rubber minimized dispersion of sound in the water coming
from reflections off the walls and bottom.
The source of the sound was an electromagnetic vibrator
of the VSP type, to the rotor of which was attached a round
membrane 120 mm in diameter. At a current frequency of 50 hertz
the emitter required 30 watts and emitted sound at a frequency
of 100 hertz. In our experiments a transformer was used that
made it possible to-obtain currents of a frequency of 20 to 50
hertz to be fed into this emitter. The frequency of the sound,
controlled by a frequency meter, accordingly varied between the
limits 40-100 hertz.
For the production of ultrasound we used a fourcore nickel magnitostriktsionnyi vibrator with a working
frequency of 23.5 kilohertz, placed on the bottom of the
aquarium with its emission surface directed either upward or
to the side. The vibrator worked on an impulse regime, the
microsecond?],
length of each impulse being about 1 mm•sec
and their frequency varied from 1 to 185 impulses per minute.
Impulses were produced by the discharge into the windings of
the vibrator of a condenser of 2 microfarads capacity charged
to a potential of 600 volts. The average computed power of
an impulse was about 300 watts.
Magnetic fields were produced by two cored magnets
and one interrupted [razorvannyi] annular magnet. The length
of the cores of the former was 200 mm; the mean radius of the
centre of the ring magnet was 200 mm, the distance between the
-2--
faces [tortsy] was 200 mm. The cores, of 30 mm diameter, were
made of tempered steel wire. The coils for the cores were
made of copper wire size PBD-0.64 and had insulation sufficient
for underwater work. The m.d.s, of each coil when the current
was on for a prolonged period was about 1000 av; for short
intervals it could be raised to 8,000-10,000 av.
The cored electromagnets were set up for observations
the behaviour of kilka in a dispersed magnetic field and in
a field of opposed types [vstrechnoodnorodnoe pole], when the
magnets were placed with like poles (north or south) opposite
each other at a distance of 50-100 mm.
qn
•The ring electromagnet was used for observations on
the behaviour of kilka when these moved through the magnetic
field between the poles. For this purpose the magnet was
placed so that only its poles were submerged in the water.
The electromagnets were supplied with either direct
current, or alternating current of 50 hertz.
The experiments were conducted when there was weak
light on deck. For observations on the behaviour of kilka in
sound and magnetic fields in conjunction with light, we used
a small-sized 25-watt electric lamp (voltage 26 volts) with a
reflector. The lamp was suspended over the middle of the
aquarium, and the radius of the circle of illumination on the
surface of the water was 250-600 mm, depending on the height
of suspension.
The aquarium was filled with water from overboard
at a temperature of about 20°C. For each experiment 50-100
of the liveliest kilka were selected.
When the non-working VSP emitter was placed under the
[page 12] surface of the water the kilka moved away from it
approximately 10 cm. Probably the cause was the • dark colour of
the emitter. After turning on the current at a sound frequency
of 100 hertz the kilka moved away from the emitter, forming an
empty zone around it of a radius 43-44 cm. Reducing the
frequency of the sound to 40 hertz weakened the effect of the
sound on the kilka.
When the deck •illumination was turned off a large
part of the fish gathered in the zone illuminated by the lamp
suspended above the aquarium. When the emitter was switched
on, the fish moved away from it, as before.
No reaction of the kilka to the electromagnetic field
was observed. Kilka which were in the fields of the electro-
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magnets, or near the electromagnets themselves, did not change
their behaviour either when the current in the windings of the
magnet was turned on, or when it was turned off. Kilka which
had assembled in the illuminated zone of the aquarium likewise
did not react to the action of the electromagnetic field.
Thus sound of frequency of 100 hertz frightens kilka,
even when they are in an illuminated zone. It is possible that
a frequency can be found to which the kilka will have a positive
reaction.
Utilization of acoustic excitation is an alluring
prospect, in view of the low power and weak current required
for sound under water, especially in the low-frequency range.
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