306
L. Véradi
INTRODUCTION
In
a
pond fish farm,
harvesting is a critical operation that requires
a
high concentration of labour and careful organization. There is an increa—
sing need
for
the
mechanization
of
fish
harvesting
for
the
following rea—
sons
:
-—
as
a
result
of
the
increasing level of intensive fish production, a large
amount of fish must be harvested in a fairly short time ;
it
is
increasing difficult to find skilled labour for this hard work ;
—
the
fishermens working conditions need to be improved ;
—
it
is
necessary
to
increase
production efficiency and to improve product
quality.
However
several specific problems and limitations have to be considered
when
planning the mechanization of fish harvesting.
Carp and other commer—
cially
valuable
cyprinids
are
cultured
in
fairly
large
earth
fish
ponds.
These
ponds,constructed
in
accordance
with
topographie,
soil
and
other
con—
ditions,
are
different
from
each
other,
even
in
the
same
farm.
Thus,
the
adaptability of standard equipment is limited and in some cases individual—
ly—designed machines have to be installed.
Another
constraint
of
the mecha—
nization
of
fish
harvesting is
the
limited
availability
of
hard—top roads
and built—in electric power lines, especially in the case of old fish ponds.
The
technical
requirements for equipment are high (easy controlabili—
;y,
durability, resistance to wet conditions, etc.)
;
on
the
other hand, the
equipment should not be expensive, taking into account the economical condi—
tions
of
pond fish farming which is different from other aquacultural indus—
tries
in
pite
of
difficulties,
traditional
fish.
harvesting
methods
have
changed considerably recently as
a
result
of
new
equipment and operational
:echnology.
The mechanized harvesting method and equipment to use are determined by
…he
type and physical condition of the fish pond to be harvested. Mechanized
fish
harvesting uses a catch—basin where the fish stock of the pond can be
collected.
An_incorporated
catch—basin
has
a
bottom
area
of
about
40
m2/ha
with a width of 10 to 25 m,
depending on the net used. Its prefereable depth
Ls
from
0,6 to 1.0 m with a 20—cm height difference between the bottoms of
:he
two
ends.
When
a
separate
catch—basin
is
used,
it
is
connected
to
the
outlet
of
the
fish
pond by a drainage canal of varying length. Its prefera—
ble
area
varies
from 15 x 50 to 20 x 70 m,
with a 20—cm height difference in
the bottoms
of the
ends.
The catch—basin does not have to be large enough to
hold
the
whole
fish
stock
of
the
pond.
When
an
incorporated basin is used,
seining and draining are carried out together. In the case of a separate ba—
sin, the fish are admitted intermittently into the basin.
The
fish
can
be
collected
in
special concrete harvesting boxes without
using nets. A 2.5 m high, lO—m long, 2—m wide concrete box is used in Israel
for harvesting a 4—ha pond (Pruginin, 1959). A common harvesting box for two
adjacent fingerling production ponds has been used with good results in Hun—
gary
(fig. 1).
dïained, seining
is
used
for harvesting. In some
avoided
_
for êîm 1
5
°C
»
emporary dralnlng problems) seining cannot be
:
p
ete harvest1ng however the pond must be drained.
L. Véradi
INTRODUCTION
In
a
pond fish farm,
harvesting is a critical operation that requires
a
high concentration of labour and careful organization. There is an increa—
sing need
for
the
mechanization
of
fish
harvesting
for
the
following rea—
sons
:
-—
as
a
result
of
the
increasing level of intensive fish production, a large
amount of fish must be harvested in a fairly short time ;
it
is
increasing difficult to find skilled labour for this hard work ;
—
the
fishermens working conditions need to be improved ;
—
it
is
necessary
to
increase
production efficiency and to improve product
quality.
However
several specific problems and limitations have to be considered
when
planning the mechanization of fish harvesting.
Carp and other commer—
cially
valuable
cyprinids
are
cultured
in
fairly
large
earth
fish
ponds.
These
ponds,constructed
in
accordance
with
topographie,
soil
and
other
con—
ditions,
are
different
from
each
other,
even
in
the
same
farm.
Thus,
the
adaptability of standard equipment is limited and in some cases individual—
ly—designed machines have to be installed.
Another
constraint
of
the mecha—
nization
of
fish
harvesting is
the
limited
availability
of
hard—top roads
and built—in electric power lines, especially in the case of old fish ponds.
The
technical
requirements for equipment are high (easy controlabili—
;y,
durability, resistance to wet conditions, etc.)
;
on
the
other hand, the
equipment should not be expensive, taking into account the economical condi—
tions
of
pond fish farming which is different from other aquacultural indus—
tries
in
pite
of
difficulties,
traditional
fish.
harvesting
methods
have
changed considerably recently as
a
result
of
new
equipment and operational
:echnology.
The mechanized harvesting method and equipment to use are determined by
…he
type and physical condition of the fish pond to be harvested. Mechanized
fish
harvesting uses a catch—basin where the fish stock of the pond can be
collected.
An_incorporated
catch—basin
has
a
bottom
area
of
about
40
m2/ha
with a width of 10 to 25 m,
depending on the net used. Its prefereable depth
Ls
from
0,6 to 1.0 m with a 20—cm height difference between the bottoms of
:he
two
ends.
When
a
separate
catch—basin
is
used,
it
is
connected
to
the
outlet
of
the
fish
pond by a drainage canal of varying length. Its prefera—
ble
area
varies
from 15 x 50 to 20 x 70 m,
with a 20—cm height difference in
the bottoms
of the
ends.
The catch—basin does not have to be large enough to
hold
the
whole
fish
stock
of
the
pond.
When
an
incorporated basin is used,
seining and draining are carried out together. In the case of a separate ba—
sin, the fish are admitted intermittently into the basin.
The
fish
can
be
collected
in
special concrete harvesting boxes without
using nets. A 2.5 m high, lO—m long, 2—m wide concrete box is used in Israel
for harvesting a 4—ha pond (Pruginin, 1959). A common harvesting box for two
adjacent fingerling production ponds has been used with good results in Hun—
gary
(fig. 1).
dïained, seining
is
used
for harvesting. In some
avoided
_
for êîm 1
5
°C
»
emporary dralnlng problems) seining cannot be
:
p
ete harvest1ng however the pond must be drained.