296
J, Oiah
INTRODUCTION
Organic fertilization is a very cheap and effective method of increasing
practically
all
nutrient
compartments
in
fish
pond ecosystems.
Unlike
inor—
ganic fertilization
this
procedure
supplies
nutrients
directly
to
algae,
bacteria,
benthic
and
planktonic animals and to some extent even to the fish
populations.
Organic
fertilization
feeds
both
the
algal and the bacterial—
detrital
food chains.
In principle the introduction from outside of any orga—
nic
materials
functions
as
an
allochtonous
organic carbon load.
In
practice
animal
manure,
domestic
sewage and green plants are the main sources of orga—
nic
enrichment.
Feeding the fish with cereals and other low—protein food is
usually
not
considered
as
organic fertilization,
in
spite of the fact that
almost
95 percent of their nutrients drives the bacterial—detrital food chain
and
only
5
percent
is
directly utilized
for
fish
growth.
In
this
context
there
is
no
any
differencelæŒween fermented poultry manure and cereal feeding.
In
both
cases,
the
pond
food
chains
are
fed
directly rather than the fish
populations.
Fish
pond manuring as a management tool
in
culture
practice has a long
history in Europe and goes back to ancient times in China.
Its
European evo—
lution
followed
the
path
of
supplementary feeding operation that is highly
developped
in
Hungary'
(Woynarovich
1956).
On
the
in
many
Asian
culture
practices,
organic
fertilization
dominated
fish
pond
operation and
feeding was additional.
Only recently,
during the seventies,
Israeli
scien—
tists
at
Dor
made
a
successful
effort
to
develop
fish
culture
techniques
relying exclusively on manuring,
feeding the pond only with manure without
any
cereals
or
pellet
and
without
any
inorganic fertilization
(Moav et al.
1977;
Rappaport et al.
1977,
1978
.
Schroeder, 1974, 1975). Later, hunger in
developing
countries
and
the
organic
waste
disposal
problem
in
developed
countries
enforced this
research trend.
In
this
paper
I
have
tried
to
synthe—
size
at
least
some
quantitative aspects of this new research trend.
Previous
results
have
been
brilliantly
reviewed
by
Winberg
and
Lyahnovits
(1965).
However
at
that
time hydrobiology was just starting as a quantitative science
and
the
basic
pathways of the production processes were very poorly quanti—
fied.
Even
today,
the
more
reliable
quantitative method
(although many are
available)
are
very
seldom
applied on fish pond research.
Few
well
trained
hydrobiologist is working in our fish ponds. Ti_recently almost all measure—
ments
of
primary production were performed by the dark—light bottle method
often
with
such
a
long
incubation
time
as
a
whole
day,
this
resulted
in
a
very
significant underestimation of the daily organic matter produced and it
was
impossible
to
understand
the
real
transfer
rates
which
determine
every—
day
fish
production
in
ponds.
Hardly'
anybody has properly'
quantified
the
pathways of the nitrogen cycle in fish ponds,
although tons of nitrogen per
hectare
are
transfered
annually
through.
such
pathways
as
ammonification,
nitrification,
denitrification
and
nitrogen
fixation.
This
situation
is
crucial
and
limits
the
further development of such a culture system as manure
feeding technology depending exclusively on energy flow and mineral cycling
along the algal and bacterial—detrital food chains.
1…
In spite of our limited understanding of the machinery of the production
processes
in manured ponds,
significant progress has been achieved by ISraeli
scientists
in
elaborating the management parameters by an empirical way that
is
conducting a number of pond experiments with varying stocking densities
and
manuring rates.
It
became
clear
at
the
beginning that common carp mono—
culture
was
not
effective
enough to utilize all the resources of the natural
J, Oiah
INTRODUCTION
Organic fertilization is a very cheap and effective method of increasing
practically
all
nutrient
compartments
in
fish
pond ecosystems.
Unlike
inor—
ganic fertilization
this
procedure
supplies
nutrients
directly
to
algae,
bacteria,
benthic
and
planktonic animals and to some extent even to the fish
populations.
Organic
fertilization
feeds
both
the
algal and the bacterial—
detrital
food chains.
In principle the introduction from outside of any orga—
nic
materials
functions
as
an
allochtonous
organic carbon load.
In
practice
animal
manure,
domestic
sewage and green plants are the main sources of orga—
nic
enrichment.
Feeding the fish with cereals and other low—protein food is
usually
not
considered
as
organic fertilization,
in
spite of the fact that
almost
95 percent of their nutrients drives the bacterial—detrital food chain
and
only
5
percent
is
directly utilized
for
fish
growth.
In
this
context
there
is
no
any
differencelæŒween fermented poultry manure and cereal feeding.
In
both
cases,
the
pond
food
chains
are
fed
directly rather than the fish
populations.
Fish
pond manuring as a management tool
in
culture
practice has a long
history in Europe and goes back to ancient times in China.
Its
European evo—
lution
followed
the
path
of
supplementary feeding operation that is highly
developped
in
Hungary'
(Woynarovich
1956).
On
the
in
many
Asian
culture
practices,
organic
fertilization
dominated
fish
pond
operation and
feeding was additional.
Only recently,
during the seventies,
Israeli
scien—
tists
at
Dor
made
a
successful
effort
to
develop
fish
culture
techniques
relying exclusively on manuring,
feeding the pond only with manure without
any
cereals
or
pellet
and
without
any
inorganic fertilization
(Moav et al.
1977;
Rappaport et al.
1977,
1978
.
Schroeder, 1974, 1975). Later, hunger in
developing
countries
and
the
organic
waste
disposal
problem
in
developed
countries
enforced this
research trend.
In
this
paper
I
have
tried
to
synthe—
size
at
least
some
quantitative aspects of this new research trend.
Previous
results
have
been
brilliantly
reviewed
by
Winberg
and
Lyahnovits
(1965).
However
at
that
time hydrobiology was just starting as a quantitative science
and
the
basic
pathways of the production processes were very poorly quanti—
fied.
Even
today,
the
more
reliable
quantitative method
(although many are
available)
are
very
seldom
applied on fish pond research.
Few
well
trained
hydrobiologist is working in our fish ponds. Ti_recently almost all measure—
ments
of
primary production were performed by the dark—light bottle method
often
with
such
a
long
incubation
time
as
a
whole
day,
this
resulted
in
a
very
significant underestimation of the daily organic matter produced and it
was
impossible
to
understand
the
real
transfer
rates
which
determine
every—
day
fish
production
in
ponds.
Hardly'
anybody has properly'
quantified
the
pathways of the nitrogen cycle in fish ponds,
although tons of nitrogen per
hectare
are
transfered
annually
through.
such
pathways
as
ammonification,
nitrification,
denitrification
and
nitrogen
fixation.
This
situation
is
crucial
and
limits
the
further development of such a culture system as manure
feeding technology depending exclusively on energy flow and mineral cycling
along the algal and bacterial—detrital food chains.
1…
In spite of our limited understanding of the machinery of the production
processes
in manured ponds,
significant progress has been achieved by ISraeli
scientists
in
elaborating the management parameters by an empirical way that
is
conducting a number of pond experiments with varying stocking densities
and
manuring rates.
It
became
clear
at
the
beginning that common carp mono—
culture
was
not
effective
enough to utilize all the resources of the natural