7114 ‎(2)‎

• UCREFRP Catalog Number: 7114
• Author: Shentyakova, L. F., et al.
• Title: Effect of an Alternating Electric Current on Fishes and Aquatic Invertebrates
• USFW Year: 1970
• USFW - Doc Type: Journal of Ichthyology
• Copyright Material: YES

The Effect of Alternating Current on
Zooplankton and Benthos

In order to determine the parameters of the
electric field of alternating current of com-
mercial frequency at which characteristic
reactions and death of zooplankton and benthos
are caused, we carried out a series of experi-
ments with planktonic crustaceans: Daphnia
longispina Muller, Bythotrephes longimanus
Leydig, Leptodora kindtli (Focke), and one
member of the henthos, Chlronomus plumosus
(L. ).

Material collected in the Volga arm of
Rybinsk reservoir at a depth of 14-18 m was
kept in the laboratory for 3-5 hours In glass
crystal pans at a temperature of 20-220C. After
this adaptation "feeble" and injured specimens
were discarded.

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Special trays of thin plastic (2.4 x 1. 2 cm
and 9.2 x 4. 0 cm) were made for the experi-
ments and stainless steel plate electrodes were
fitted on the two oppos Ite stands. When the
alternating current was switched on a uniform
electric field was created in the tray. The
trays were not too high to be placed beneath
the objective of a microscope. A single
experimental animal was placed In a tray, a
definite difference of potentials was created
in the electrodes and observations were made
through the microscope (ocular x 8, objective
x 0.6). The time for which the current was
effective was 1 sec. The interval between dif-
ferent electrode strengths was at least 5 min.
Water taken from the reservoir was poured
into the tray at a temperature of 20-220C.
The electric conductivity of the water was in
the range (1. 5-2.1) . 10-4 ohm)1 . em-I.

A total of 155 experiments was carried out
with four species of hydrobionts (1110 speci-
mens). Electric field strength was determined
in these experiments and the nominal voltage
of the body of the animal (Ul) was calculated
by multiplying the electric field strength (E)
b)' the total length (l) of the animal. We also
determined the parameters of the electric
field for 3 reactions of the animals (commence-
ment of excitation, commencement of electro-
narcosis or shock and commencement of
death). When the voltage in the electrodes
was low the animals did not feel the existence
of the electric current. When a higher voltage
was used there were sharp spasmodic move-
ments of the body (excitation stage). Thus,
Daphni~ longispina became more active when
the fiel strength was 1.97 v/cm, Bythotrephes
longimanus and Leptodora kindtli became more
active at 0.625 v/cm and Chironomus plumosus
at 0.195 v/cm. When the potential difference
was further increased the stage of electro-
narcosis began. However, the movements of
the animals were renewed as soon as .the -
voltage in the dish electrodes disappeared.
Thus, In experiments with Daphnia longispina

the stage of electronarcosis began when the field
strength was 9.5 v/cm (current density 1.65
m amp.! cm2). with Bvthotrephes 10llj?;imanus It
began at4.6v/cm current density 0.74 m amp per
cm2), with Leptodorl! ]<:indt\! at 3.22 v/cm
(current density 0.58 m amp/cm2) and with
Chironomus plu/us at 5.18 v/cm (current den-
sity 0.88 m amp cm2). Death occurred follow-
ing a very large increase in fi eld strength. The
death of Daphnia longisplna occurred at a field
strength of 14.28 v/cm (current density 2.49
m amp/cm2), that of B~hotrephes longimanus
at 10.21 v/cm (current ensity 1. 4 m amp/cm2)
and that of Leptodora kindtii at 5. 21 v/cm (0.95
m amp/cm2). Chironomus plumosus did not
die even when the electric field strength was
very high (following exposure for 1 sec).

The experimental data were processed by
Nairi computer. Statistical processing was
carried out for three reactions (excitation,
electronarcosis and death), for field strength
(E v/cm), current density (ollamp/cm2), the
nominal voltage of the body of the animal (U v)
and the size of the animal (1 cm. 10-2). The
significance of the data was verified by the
normalized deviation (t); it was above 0.99 for
all the Indices. ~aphnia longispina needed th,l)
greatest electric ield strength to caUSe excita-
tion, electronarcosis and death, Bythotrephes
longimanus needed a lower field strength and
Leptodora kindtli needed the lowest field
strength. It is evident that the reaction of
crustaceans to electric field strength Is depen-
dent on their size. Small crustaceans need a
higher field strength than do large ones. Thus,
Daphnia longispina, which has a mean body
length of O. 21 cm perishes at 14.3 v/cm,
Bythotrephes longimanus, which is 0.29 cm
long, perishes at 10.2 v/cm and Leptodora,
which is 0.55 cm long, perishes at 5.2 v/cm.

Experiments were carried out on the sur-
vival of D:Phnia longispina, . Bythotrephes longi-
~ an Chlronomus plumosus following eX-
posure to electric fields of different strengths.
Ten animals at a time were placed in the dish
and subjected to the action of an electric field
of known strength for 1 sec. The animals
were then placed in glass crystal pans and their
survival was observed. The results of the
experiment were recorded on the following day.
A control was set up in parallel with the experi-
ment. This experiment established a tendency
for reduction in the survival of Daphnia longi-
spina and Bythotrephes longimanus as electric
1'IeTif""strength increased:,,-.

In connection with the very high resistance
of Chironomus plumosus to high electric field
strengths exposure In experiments with it was
increased to 180 sec at a field strength E =
= 22.8 v/cm and to 60 sec at a strength of 38
v/cm.

The survival of Chironomus plumosus was
70"1. in the experiments in which exposure

370

Table 6

StatiStltC~1 indices of experiments on electric field strength (v Icm)
curren .ensity (llamp/cm2) and nominal voltage of the body of th
. ammals (Ul = E . l = v) following exposure fo 1 e

r sec
'Reaction Species used in Size 1, cr,p
experiment em E.', v/cm ampl cm2 C,.V
Excitation Daphnia longispina 0.21
l. 968 345.3 n.44
Bythotr~p'ull longimorl.lu 0.29 0.625
Lt!ptodora kindW 105.5 0.18
Chironomlls plW7lo8U$ 0.55 0.635 lt5.6 0.34
EIecbonarcosis DaphnIa longispina 2.05 0.195 32.7 0.40
0.21 9.499 1647.6
8ythotr~phi's longimanus 0_29 4.604 740.4. 2.0
up/aflora klndlii 1.34
Chironomus plW7108US 0_55 3.217 ~B2.6 1.91
Dea.th Daphnia longispina 2.05 5.176 878.9 JO.li.)
0.21 14.277 2~98.5
Bythotrephes longimanw 0.29 10.209 3.11
LFptodora kindtit 1i4n.7 ;:U~'f
0.55 5.208
Chironomus plumosus 2.05 932.1 2.HJ

wa~ 180 sec and 10 % in the experiments in
whl~h .exposure was 60 sec. Survival was
1001. m the control in both experiments.,

Conclusions

1. No differences In the quantity of living
and damaged animals Were discovered in
samples of zooplankton and benthos taken after
the passage of an electrified trawl and in
front of it.

~. No dead fish were noted in visual obser-
vatIOns ?f the _surface of the water in Rybinsk
reservoir behmd the electrified trawl over a
path 25 km long.

3. N~ dead and damaged fishes were dis-
cover.ed m.the bottom water layers In benthic
traw~mg Wit? an ordinary 22 meter trawl
carried out Immediately behind the electrified
trawl.

4. The catching capacity of the electrified
trawl by ~omparison with the catching capacity
of an ordmary trawl was 125, 249 and 263"/.
In different areas of Rybinsk reservoir. 0

5. The exposure of breeding perch blue
bream_, roach and bream to a uniform 'ac
electriC field (fishes in a state of shock for 5
sec) had no effect on the spawning capacity of
these fIshes and on the subsequent growth of
the young.

6. .The state of shock lasting 5 sec pro-
duc.ed m cyprinids by the effect of an alter-
natmg current of commercial frequency had
no effect on their survival and growth when
they ~.ere Subsequently kept under pond
CondItions.

7. The action of ac electric fields at
strengths of between hundredths of a volt/cm
~d a few volts/cm on fertilized perch eggs
dId not have a lethal effect on their develop-
ment and on the hatching of pro larvae.

.-'--"

8. The survival of perch prolarvae and
larve in different stages of development was
the same In the experiment and in the control
following the action of an alternating current at
different electric field strengths (0.6-3.0 v/cm).

9. The survival of white bream eggs and
pro larvae and of underyearling blue bream and
roach at an age of 2 months following the action
?f an altern>:ting current on them was no lower
m the ~xperlments than in the control even
followmg exposure to electric fields of high
strength (E = 3-5 v/cm) more than ten times
the strength of the electrified trawl.

10. ~ncrease In exposure to the effect of
alternatmg current (field strength 2.5 v/cm)
fro_m 1 to 5 min did not lower the survival of
whIte bream larvae.

11. Following the exposure of roach to an
ac electricyeld of strength 0.3 v/cm for 12 Sec
the glycemia level was increased only in part
of the fIshes and this Increase did not exceed
tbe ?yperglycemia range found in fishes under
the mfluence of natural factors.

. 12. The parameters of the ac electric
fields causing the following reactions after ex-
posure for 1 sec were determined for 3 species
of.planktonic crustaceans, Daphnia longispina
Muller, Bythotrephes ]ongimanusLevdig: and
Leptodora kindtii (Focke): excitatio'; (E';' 0.6-
2.0 v/cm), electronarcosis (E = 3.2-9.5 v/cm)
and death (E = 5.2-14.3 v/cm). For Chyrono-
mus pJumosu!, (L.) the electric field parameters
"ere etermmed only for the excitation reac-
~lon (E = 0.2 v/cm) and electronarcosis (E =
- 5.2 v/cm) followmg exposure for 1 sec and
the death of this benthic animal following'such
exposure did not Occur even when the electric
field strength was very high.

13. The survival of zooplankton and
be~thos is lowered as electric field strength
IS Increased. Following exposure for 180 sec
to a ~ield with a strength of 22. 8 v/cm the
surVIval of Chironomus plumosus was 7001. ,

371