280
The carnivore species aquaculture is separate from basic food production, particularly in
animal protein food production because this
production method reduces the amount of food.
The global production of carnivorous species
are going to continue; however, as pointed by
FAO, over 80 % of natural resources as human
food are already overexploited. Baitfish
resources for aquaculture are also included in
overexploited natural resources. In addition, as
pointed out previously (Yamane 2010), nonfood use consumption indicates a decreasing
trend in the recent 10 years, and it is assumed
that the amount of human direct consumption is
one of the major factors. When considering the
actual state in the global fishery production, it
is very important to improve the roundabout
production system of carnivore fish aquaculture
system. To make optimum food production system for humans, a potential of bias on both
quantity and quality of fishery production that
reflect on the state of natural stocks should be
considered. Natural resources are finite and we
could not overuse these organisms’ sustainable
self-recovery.
For example, a simple production model is
proposed under several limitations. As a first
step, a logistic model was used to describe the
relationship between quantity of baitfish production and total capture fishery production.
As a representation of the problem, only the
relationship between the quantity of fish production of capture fishery and those of aquaculture is described. To obtain the best capacity of
fishery products, the percentage for each production unit as optimum production was figured
out. The relationships between total fishery production, total capture fishery products, and
those for aquaculture can be defined as (Kadota
et al. 2012)
T
y
f
y
f
f
= −
( ) + ( )
1 α
α
(1)
where T is the total fishery products, y f is the total
product from capture fishery, f(αy f ) is total aquaculture products, and α is a parameter indicating
percentage of baitfish supplied for aquaculture
feed.
Since aquaculture production may be subjected to a restriction such as quantity of the permitted area, environmental conditions, etc., it is
assumed that the production would hit a peak
somewhere. Here, as a model, Eq. (2) was chosen
representing the relationships between total fishery products, total capture fishery products, and
aquaculture products:
f y
A
f
y f
α
βα
( ) = −
(
)
−
1 e
(2)
where A and β are constant coefficients concerning capture fishery products. Developing Eq. (2),
the following equation is obtained to represent
total fishery products and other production units:
T
y
A
f
y f
= −
( ) + −
(
)
−
1
1
α
βα
e
(3)
α
β
β
=
( )
ln A
y f
(4)
Since actual data of baitfish used for aquaculture could not be identified, the α values were
calculated with the known value A as 40 % of
total capture products and 50 % of nonfood use
allotted to aquaculture baitfish (Fig. 10). The data
applied for calculation is the 2006 FAO data.
According to the estimated value to obtain the
optimum production level from given stocks,
17 % of capture products allotted to aquaculture
baitfish would result in peak total fishery production. Though under limited conditions, the results
would represent the actual state.
T. Yamane
The carnivore species aquaculture is separate from basic food production, particularly in
animal protein food production because this
production method reduces the amount of food.
The global production of carnivorous species
are going to continue; however, as pointed by
FAO, over 80 % of natural resources as human
food are already overexploited. Baitfish
resources for aquaculture are also included in
overexploited natural resources. In addition, as
pointed out previously (Yamane 2010), nonfood use consumption indicates a decreasing
trend in the recent 10 years, and it is assumed
that the amount of human direct consumption is
one of the major factors. When considering the
actual state in the global fishery production, it
is very important to improve the roundabout
production system of carnivore fish aquaculture
system. To make optimum food production system for humans, a potential of bias on both
quantity and quality of fishery production that
reflect on the state of natural stocks should be
considered. Natural resources are finite and we
could not overuse these organisms’ sustainable
self-recovery.
For example, a simple production model is
proposed under several limitations. As a first
step, a logistic model was used to describe the
relationship between quantity of baitfish production and total capture fishery production.
As a representation of the problem, only the
relationship between the quantity of fish production of capture fishery and those of aquaculture is described. To obtain the best capacity of
fishery products, the percentage for each production unit as optimum production was figured
out. The relationships between total fishery production, total capture fishery products, and
those for aquaculture can be defined as (Kadota
et al. 2012)
T
y
f
y
f
f
= −
( ) + ( )
1 α
α
(1)
where T is the total fishery products, y f is the total
product from capture fishery, f(αy f ) is total aquaculture products, and α is a parameter indicating
percentage of baitfish supplied for aquaculture
feed.
Since aquaculture production may be subjected to a restriction such as quantity of the permitted area, environmental conditions, etc., it is
assumed that the production would hit a peak
somewhere. Here, as a model, Eq. (2) was chosen
representing the relationships between total fishery products, total capture fishery products, and
aquaculture products:
f y
A
f
y f
α
βα
( ) = −
(
)
−
1 e
(2)
where A and β are constant coefficients concerning capture fishery products. Developing Eq. (2),
the following equation is obtained to represent
total fishery products and other production units:
T
y
A
f
y f
= −
( ) + −
(
)
−
1
1
α
βα
e
(3)
α
β
β
=
( )
ln A
y f
(4)
Since actual data of baitfish used for aquaculture could not be identified, the α values were
calculated with the known value A as 40 % of
total capture products and 50 % of nonfood use
allotted to aquaculture baitfish (Fig. 10). The data
applied for calculation is the 2006 FAO data.
According to the estimated value to obtain the
optimum production level from given stocks,
17 % of capture products allotted to aquaculture
baitfish would result in peak total fishery production. Though under limited conditions, the results
would represent the actual state.
T. Yamane