Economic analysis of a pilot commercial produc

Aquaculture Research, 2002, 33, 1265 1272

Economic analysis of a pilot commercial production for
spotted babylon, Babylonia areolata (Link 1807), of
marketable sizes using a flow-through culture system
in Thailand
N Chaitanawisuti1, S Kritsanapuntu2 & Y Natsukari3
1

Aquatic Resources Research Institute, Chulalongkorn University, Bangkok, Thailand

2

Department of Bioproducts, Prince of Songkla University, Suratani, Thailand

3

Department of Fisheries, Nagasaki University, 1 14, Bunkyo Machi, Japan

Correspondence: N Chaitanawisuti, Aquatic Resources Research Institute, Chulalongkorn University, Bangkok, Thailand 10330.
E-mail:

Abstract
This article examines the economic considerations
involved in the production of spotted babylon (Baby­
lonia areolata) in Thailand. A financial analysis of
the construction and operating costs of a pilot com
mercial production of spotted babylon of marketable
sizes is provided, based upon proven practical tech
niques and production data for a flow through
growout system. The investment required for a spot

ted babylon growout hatchery producing 990 kg per
year is estimated to be US$4528.8. The annual cost
of operating such a hatchery is estimated to be US
$4624.1. The cost of producing 990 kg of market
able size spotted bablyon with a survival rate of 95%
is estimated to be US$4.91 per kg of snails produced.
Cash flow analysis showed that a constant selling
price of US$5.8 kg-1 results in positive cash flow by
year 4. The proposed enterprise is marginally feas
ible if cost can be considerably reduced by targeting
production and integrating hatchery and growout
operations.
Keywords: Babylonia areolata, economic analysis,
flow through, growing out, seawater system,
spotted babylon
Introduction
Recently, there has been considerable interest in the
commercial culture of spotted babylon, Babylonia
© 2002 Blackwell Science Ltd

areolata (Link), in Thailand. This interest is the result
of a growing demand and an expanding domestic
market for seafood, along with a catastrophic de
cline in natural spotted babylon populations in the
Gulf of Thailand. There is no published information
on the economics of spotted babylon aquaculture in
Thailand. A lack of economic data can be an import
ant constraint to the successful development of
spotted babylon aquaculture. A financial investment
analysis linking biological, production, cost and

market price variables can be used to make decisions
about culture methods and the type and feasibility of
any commercial operation. An accurate economic
assessment of spotted babylon culture is necessary if
producers are to make informed decisions regarding
the potential of this enterprise. The analysis pro
vided here describes the relationships between
yield (growth and survival), market price, fixed
and variable costs, and profitability indicators.
From 1998 to 2000, Chulalongkorn University con
ducted a collaborative research and development
project with the National Research Council of
Thailand (NRCT) to develop the land based aqua
culture systems for large scale seedling production
and growout operations for spotted babylon, Baby­
lonia areolata, in Thailand, with a view to then
transferring the methods and techniques to hatch
ery based operations in Thailand (Chaitanawisuti &
Kritsanapuntu 2002). This study is the first attempt
to present economic considerations based on the
results of a pilot scale (ten growout ponds) culture
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A pilot commercial production for spotted babylon N Chaitanawisuti et al.

Aquaculture Research, 2002, 33, 1265 1272

operation for spotted babylon, B. areolata, of market
able sizes in a flow through culture system.

Table 1 Parameters used for economic analysis of grow
out operation of spotted babylon B. areolata, using a flow
through culture system

Materials and methods

Parameter

Value

Farm size
total farm area (m2)
Pond size (m)
Total pond area (m2)

300
3.0 x 4.5 x 0.5
135

Stocking data
Average initial weight of juvenile (g)
Stocking density (no. m-2)
Stocking density (no. per pond)

0.30
400
5, 500

Harvest data

Duration of growout (days)
Pond preparation (days)
Average number of crops per year per pond
Average final weight (g)
Survival (%)
Feed conversion ratio
Average yield per pond (kg)
Average yield per crop (kg)
Total annual farm yield (kg)

180
5
2
9.0
95
1.8
49.5
495
980.4

Sale price (US$ kg-1)

4.5 5.8

Pilot-scale growout trial
A pilot commercial growout trial was conducted at
a mollusc hatchery at Sichang Marine Science
Research and Training Station, Chulalongkorn
University, Thailand. Juveniles were grown to
marketable size using the culture methods described

by Chaitanawisuti and Kritsanapuntu (1997,
1998, 1999a, b). A total of 55 000 hatchery reared
juvenile B. areolata (average body weight 0.30 g)
were held in 10 3.0 x 4.5 x 0.5 m (width x length
x height) rectangular canvas ponds at a density of
400 snails m-2 (5500 per pond). The culture ponds
were supplied with flow through ambient natural
seawater at a rate of 150 L h-1 for 24 h, and water
depth in the rearing ponds was 30 cm. The pond
bottom was covered with coarse sand as a substra
tum. The juveniles were fed with fresh meat of
carangid fish, Selaroides leptolepis, to satiation once
daily. Thirty per cent of individual snails were
sampled for growth measurements at 30 day inter
vals and growout duration was 180 days per cycle.
On day 180, the individual final weight and
feed conversion ratio averaged 9.0 ± 0.8 g and
1.8 ± 0.4 respectively. The final survival rate was
95%. Based on continuous and year round produc
tion, all 10 growout pond facilities were stocked by
month 1 and first harvest began by month 6. Five
days was allowed for pond clean up and restocking.
Each pond was harvested twice during a 1 year
cycle. Based on growth data from the pilot study,
95% of the snails reached market size by day 180, at
an average weight of 9.0 g. The average yield was
49.5 ± 12.3 kg per pond (495 kg per cycle), and
total annual yield was 990 kg (Chaitanawisuti &
Kritsanapuntu 2002). Table 1 summarizes the pro
duction and harvest data used for the economic

analysis. Duration of growout and average weight
at harvest are based on the results of the pilot study.

Financial analysis
A financial analysis was conducted of 10 growout
pond facilities, based on investment costs and pro
duction and marketing data from the pilot scale
trials. The analysis was used to determine and
1266

analyse critical relationships between stocking dens
ity, harvest size, survival, and pond management
factors that affect yield; capital and operating costs;
and market price. The components of the economic
analysis include the following.
Capital costs
Facilities and equipment costs and economic life of
the proposed 10 growout pond facility for spotted
babylon production are presented in Table 3. The
production system consists of 25 13.0 x 4.5 x 0.5 m
canvas ponds arranged in a 5 x 5 array, with
common walls to reduce construction costs. The
growout ponds are supplied with flow through am
bient natural seawater for 24 h from a seawater
intake system. The seawater intake consists of a
50 mm diameter PVC pipe manifold horizontally
into the sea. Seawater is delivered to each pond
through 50 mm PVC main pipes and 1 inch
diameter PVC distribution pipes. The seawater
system is powered by one a 1 hp water pump. Sea

water flow rate to the ponds is adjusted to provide
an exchange rate of 3.5 t day-1, and drainage of
each pond is accomplished by a standpipe 40 mm
in diameter. The ponds are not aerated. Thus, for the
economic analysis, it was assumed that snails can
© 2002 Blackwell Science Ltd, Aquaculture Research, 33, 1265 1272


Aquaculture Research, 2002, 33, 1265 1272

A pilot commercial production for spotted babylon N Chaitanawisuti et al.

grow in full strength seawater, which can be
pumped from the shore adjacent to the growout
facility. High growth and survival of spotted babylon
from juvenile to marketable size in flow through
seawater is well documented (Chaitanawisuti &
Kritsanapuntu 1999). Feed is stored in one 1.5 m3
freezer. Building requirements include a 300 m2
shed for a juvenile growout area and for sorting
harvested snails. The shed is enclosed with a sheet
zinc roof and has a concrete floor. Interest rates for
capital cost are based on bank loan rates for 2000
(3.5% per year) for this type of business enterprise
and calculated on an average investment basis.
Fixed costs
Annual depreciation is estimated from the expected
useful life of each asset, and all equipment and
facilities are assumed to have no residual value at
the end of their useful life. The hatchery building

and all the growout ponds are assumed to have a
useful life of 10 years because of the saltwater envir
onment. Housing and the seawater pump have been
assigned a useful life of 5 years. The life expectancy
of equipment ranges from 3 to 5 years. Salaries
(general manager, production manager and ac
countant/secretary) and overheads (insurance,
property taxes, licence fees and permits) are not
estimated. Land is assumed to be leased from the
land authority at a rate of 36 000 baht per year.
Interest rates for equipment, pond construction and
water supply are based on bank loan rates for 2000
(3.5% per year) for this type of business enterprise
and calculated on an average investment basis.
Variable costs
The variable costs for a 10 pond operation are pre
sented in Table 4. Spotted babylon juveniles (aver
age body weight 0.30 g) would be purchased from a
commercial hatchery at 0.8 1.0 baht per juvenile.
Juveniles would be fed fresh meat of carangid fish
once daily to satiation at a cost of 15 baht per kg
and feed conversion ratio of 1.8. Annual repair and
maintenance is estimated at 3% for building, pond
construction and operating equipment costs. Electri
city would be purchased at a cost of 1.3 baht per
kWh. Labour requirements include one full time
labourer at a rate of 5000 Baht per month. Oper
ation equipment (vehicle, fuel, storage containers,
farm shop equipment, etc.) is not estimated.
Chemicals costs include analytical reagents and

hyperchlorite powder. Miscellaneous costs include
© 2002 Blackwell Science Ltd, Aquaculture Research, 33, 1265 1272

telephone, fresh water, materials and supplies. Inter
est charges for operating capital are based on bank
loan rates for 2000 (3.5% per year) for this type of
business enterprise and calculated on an average
investment basis.
Return analysis
Net return and return on investment for hatchery
production were computed at an average final sur
vivals of 95% and a selling price of spotted babylon
of marketable sizes ranging from US$4.5 to 5.8 per
kg. Gross return was calculated for each level of final
weight (range 7.0 10.5 g) and for selling price. Net
return was calculated as gross return minus produc
tion cost. Return to capital and management was
computed for each level of final weight and each
selling price by subtracting annual operating cost
from gross returns. Subsequently, return on invest
ment was estimated by dividing returns to capital
and management by initial capital investment
(Fuller, Kelly & Smith 1992).
Cash flow
An annual production budget was developed from
the variable and fixed costs, and cash flow budgets
were developed to examine profitability in relation
to the timing of expenditures and earning. Net cash
flow was determined by projecting estimated rev
enues and costs over a 10 year period because an

aquaculture enterprise would not be an attractive
investment opportunity if it was not profitable
within this period. The cash flow analyses were
performed at constant prices. The initial capital in
vestment was charged in the first year, and costs in
subsequent years included annual variable and fixed
costs, and replacement costs of depreciation items.
Construction and snail acquisition occur in the first
year, and variable costs were adjusted to account for
no sales during the first 6 months of operation
(Rubino 1992; Head, �erbi & Watanabe 1996).

Results
Initial investment requirement for construction of
the growout hatchery was US$4528.8 (Table 2).
Construction of the building and construction of
the growout ponds were the largest cost compon
ents, representing 50.78% and 20.30% of the total
investment cost respectively. These two components
of the hatchery represented 71.08% of total invest
ment requirements. The laboratory equipment and
1267


A pilot commercial production for spotted babylon N Chaitanawisuti et al.

highest variable costs, accounting for, respectively,
29.85% and 27.37% of the total annual costs. Elec
tricity and feed were next most expensive operating
cost items, representing 11.93% and 10.44% of

total annual cost. The cost associated with produ
cing spotted babylon marketable sizes is expressed as
US$ per kg. Costs per kg at selected final weight are
presented in Table 5. The cost of producing 990 kg
marketable sizes in this hatchery design was esti
mated at US$4.66 per kg. Production under condi
tions of 95% survival, final weight of 9.0 g and
selling price of US$5.8 per kg showed the best
results in this study. Gross return at these levels
was US$5747.2 (Table 6) and net return for pro
duction was US$1128.2 (Table 7). Returns on
capital and management, and returns on invest
ment were US$1803.2 and US$0.39 respectively
(Tables 8 and 9). Cash flow budgets were developed
to examine profitability in relation to the timing of
expenditures and earning (Table 10). These condi
tions, at a constant selling price of US$5.8 per kg,
would result in a positive cash flow by year 4. The
proposed enterprise would be marginally feasible if
costs could be considerably reduced by targeting
production and by vertically integrating hatchery
and growout operations.

water supply were the second most expensive items
in equipping the hatchery, representing 15.24% and
10.14% of the total investment respectively. Details
of investment costs, annual depreciation, economic
life and annual interest charges for a 10 13.0 x
4.5 x 0.7 m growout pond facility are presented in
Table 3. Annual ownership costs were estimated to

be US$676.60, with annual operating costs esti
mated at US$3947.5. Total annual cost for the
marketable size production of spotted babylon cul
ture was US$4624.1 (Table 4). Annual ownership
and operating costs accounted for 14.61% and
85.39% of the total annual cost respectively. The
two major ownership cost items were depreciation
at 12.62% and interest on investment at 1.99% of
total annual cost. The hired labour and initial pur
chase of the spotted babylon juveniles were the

Table 2 Initial investment requirements of 10 growout
ponds for spotted babylon B. areolata marketable sizes in
flow through culture system
Cost
(US$)

Item

Per cent of
total cost

Buildings (roof and concrete
floor of 300 m2)
Pond construction (10 3.0 x
4.5 x 0.5 m canvas ponds)
Laboratory equipment (freezer,
water quality devices
and lab equipment)
Water supply and drainage

(seawater pump of 2.7 kW
and pipe, valves and couplings)
Aeration (air blower of 2 kW
and airline)

2298.9

50.78

919.5

20.30

689.7

15.24

459.8

10.14

160.9

3.54

Total cost

4525.8

Aquaculture Research, 2002, 33, 1265 1272

Discussion
The feasibility of producing B. areolata of marketable
sizes in a pilot commercial growout operation was
examined. Although returns are small, production
with 95% survival and selling price of US$5.8 per kg
is economically feasible under the assumptions
employed. This study presented a positive net
return, and positive levels of return and a payback
period of less than 10 years are often used as

100

Table 3 Estimated depreciation, interest charges, and repairs and maintenance of 10 growout ponds for B. areolata
marketable sizes in flow through culture system

Item

Cost
(US$)

Buildings
Pond construction
Laboratory equipment
Water supply and drainage
Aeration

2298.9
919.5
689.7

458.9
160.9

10
10
5
5
5

229.9
91.9
137.9
91.9
32.2

80.5
3.2
4.8
3.2
1.1

Total cost per year

4528.8

583.8

92.8

135.8

1268

Economic life
(years)

Annual depreciation
(US$)

Annual interest
charges (US$)

Annual repair and
maintenance (US$)
68.9
27.6
20.7
13.8
4.8

© 2002 Blackwell Science Ltd, Aquaculture Research, 33, 1265 1272


Aquaculture Research, 2002, 33, 1265 1272

A pilot commercial production for spotted babylon N Chaitanawisuti et al.

Table 4 Annual enterprise budgets for a ten pond aquaculture facility for spotted babylon, B.
areolata. A stocking density of 400 per m2 and a wholesale price of 5.8 US$ per kg are assumed

Item

Value

Variable costs (US$)
Repair and maintenance
Hired labours
Feed
Juvenile purchase
Electricity
Interest on operating capital

135.8
1379.3
482.8
1264.4
551.7
133.5

Total variable costs (US$)

3947.5

Fixed costs (US$)
Depreciation
Interest of investment capital
Total fixed costs (US$)
Total annual costs (US$)

583.8

92.8
676.6
4624.1

Per cent
variable

Per cent of
total cost

3.42
34.96
12.21
32.06
13.97
3.38

2.92
29.85
10.44
27.37
11.93
2.88

100

85.39

86.37
13.63

12.62
1.99

100

14.61
100

Table 5 Estimated total annual cost for production of spotted babylon at selected final weights
and 95% survival rate
Final weight
(g)

Number of
snails per kg

Production
(kg)

Total annual
cost (US$)

Cost per kg
(US$)

7.0
7.5
8.0
8.5

9.0
9.5
10.0
10.5

142
133
125
117
111
105
100
95

774.6
827.0
880.0
940.2
990.9
1047.6
1100.0
1157.9

4619
4619
4619
4619
4619
4619
4619

4619

5.96
5.59
5.25
4.91
4.66
4.41
4.19
3.99

Table 6 Gross return* for production of spotted babylon marketable sizes at selected final
weight, 95% of survival rate and selling prices
Selling price (US$ per kg)

Final weight (g)

Production (kg)

4.5

5.1

5.5

5.8


7.0
7.5

8.0
8.5
9.0
9.5
10.0
10.5

774.6
827.0
880.0
940.2
990.9
1047.6
1100.0
1157.9

3485.7
3721.2
3960.0
4230.9
4459.1
4714.2
4950.0
5210.6

3950.5
4217.7
4488.0
4795.0
5053.6

5342.8
5610.0
5905.3

4260.3
4548.5
4840.0
5171.1
5449.9
5761.8
6050.0
6368.5

4492.7
4796.6
5104.0
5453.2
5747.2
6076.1
6380.0
6715.8

*Gross return was computed for each level of final weight ranging from 7.0 to 10.5 g and selling price
(US$4.5 5.8).

© 2002 Blackwell Science Ltd, Aquaculture Research, 33, 1265 1272

1269

A pilot commercial production for spotted babylon N Chaitanawisuti et al.

Aquaculture Research, 2002, 33, 1265 1272

Table 7 Net return* for production of spotted babylon marketable sizes at selected final
weights, 95% of survival rate and selling prices
Selling price (US$ per kg)

Final weight (g)

Production (kg)

4.5

5.1

5.5

5.8


7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5

774.6
827.0
880.0
940.2
990.9
1047.6
1100.0
1157.9

-1133.3
-897.8
-65.9
-388.1
-159.9
95.2
331.0
591.6

- 668.5
-401.3
-13.1
176.0
434.6
723.8
991.0
1286.3

-358.7
-70.5
22.1

552.1
830.9
1142.8
1431.0
1749.5

-126.3
117.6
48.5
834.2
1128.2
1457.1
1761.0
2096.8

*Net return was calculated from the gross return minus the total production cost (US$4624.1).

Table 8 Return on capital and management* for production of spotted babylon marketable
sizes at selected final weights, 95% of survival rate and selling prices
Selling price (US$ per kg)

Final weight (g)

Production (kg)

4.5

5.1

5.5

5.8


7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5

774.6
827.0
880.0
940.2
990.9
1047.6
1100.0
1157.9

-458.3
-222.8
16.0
286.9
515.1
770.2
1006.0
1266.6

6.6
273.7
544.0
851.0
1109.6
1398.8
1666.0
1961.3

316.3
604.5
896.0
1227.1
1502.9
1817.8
2106.0
2424.5

548.7
852.6
1160.0
1509.2
1803.2
2132.1
2436.0
2771.8

*Return to capital and management was computed for each level of final weight ranging from 7.0 to 10.5 g
and each selling price by subtracting annual operating cost (US$3947.5) from gross returns.

Table 9 Return on investment* for production of spotted babylon marketable sizes at selected
final weights, 95% of survival rate and selling prices
Selling price (US$ per kg)

Final weight (g)

Production (kg)

4.5

5.1

5.5

5.8


7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5

774.6
827.0
880.0

940.2
990.9
1047.6
1100.0
1157.9

-0.10
-0.50
0.003
0.06
0.11
0.17
0.22
0.28

0.001
0.60
0.12
0.19
0.25
0.30
0.37
0.43

0.07
0.13
0.19
0.27
0.33
0.40

0.46
0.53

0.12
0.19
0.26
0.33
0.39
0.47
0.54
0.61

*Return on investment was estimated by dividing returns to capital and management by initial capital
investment (US$4528.8).

1270

© 2002 Blackwell Science Ltd, Aquaculture Research, 33, 1265 1272


Aquaculture Research, 2002, 33, 1265 1272

A pilot commercial production for spotted babylon N Chaitanawisuti et al.

Table 10 Ten year cash flow of a pilot commercial production for spotted babylon, B. areolata, marketable sizes using ten
growout ponds in a flow through culture system. Annual production of 990 kg and selling price of US$5.8 kg-1

Year

Variable cost

(US$)

Fixed cost
(US$)

Investment
(US$)

Total annual
cost (US$)

Receipt
(US$)

Net return
(US$)

Cumulative
(US$)

Year 1
Year 2
Year 3
Year 4
Year 5
Year 6
Year 7
Year 8
Year 9
Year 10

3947.5
3947.5
3947.5
3947.5
3947.5
3947.5
3947.5
3947.5
3947.5
3947.5

676.6
676.6
676.6
676.6
676.6
676.6
676.6
676.6
676.6
676.6

4528.8
0
0
0
0
0
0

0
0
0

9152.9
4624.1
4624.1
4624.1
4624.1
4624.1
4624.1
4624.1
4624.1
4624.1

5747.2
5747.2
5747.2
5747.2
5747.2
5747.2
5747.2
5747.2
5747.2
5747.2

-3405.7
1123.1
1123.1
1123.1

1123.1
1123.1
1123.1
1123.1
1123.1
1123.1

-3405.7
-2282.6
-1159.5
36.4
1159.5
2282.6
3405.7
4528.8
5651.9
6775.0

business investment criteria. The relative attractive
ness of an investment should also include an evalu
ation of markets and realistic sale, site selection,
technology and management requirements. In Thai
land, live spotted babylon fetched selling prices
ranging from US$9.2 to 13.8 per kg at seafood
restaurants and US$5.5 6.5 per kg at farm outlets.
The basic conditions in this study (juvenile price of
US$0.02 per juvenile, production feed price of
US$0.3 per kg, stocking density of 400 m-2 and
selling price of US$5.8 per kg) resulted in a net
return and a return on investment of US$1128.2

and US$0.39 respectively. This indicates that the
proposed 10 growout pond operation is economic
ally feasible under these conditions. Decreasing
the culture period to 5 months and decreasing the
juvenile prices to US$0.01 per juvenile improves
the economic feasability. Aeration and/or water ex
change are necessary for flow through culture
systems and have been accounted for in the present
economic analysis. Profitability can be improved by
targeting production and market prices and areas.
With regard to production, profitability indices were
most sensitive to changes in average final weights
and survival. In general, snails are rendered unmar
ketable by stunting and deformity characteristics
which are presumably genetically based, and
which are related to lowered growth rates (i.e.
final average weights) and survival.
To summarize, the results of an economic analysis
of a proposed 10 pond production system for spotted
babylon, based on pilot production data, suggest
that the enterprise would be commercially feasible
at current selling prices at a final body weight of
9.0 g, marginally feasible at 8.0 g and uneconomical
© 2002 Blackwell Science Ltd, Aquaculture Research, 33, 1265 1272

at 6 7 g. Costs can be considerably reduced by re
ducing the culture period, improving growth and
survival and using locally hatchery and growout
operations. Vertical integration of a hatchery oper
ation with the growout phase can substantially im

prove economic feasibility. This economic analysis is
intended as a guide and must be modified to reflect
individual situations.

Acknowledgments
We would like to thank the National Research
Council of Thailand (NRCT) for its support of
the project. Thanks also go to Professor Piamsak
Menasveta & Associated Dr Somkiat Piyatiratitivor
akul for their advice and guidance. Lastly, we would
like to thank Mr Soonthorn Thepmoon, Miss Siriwan
Kathinmai, Mr Mongkol Maklit & Mr Sailom
Tantulvawit for their assistance during the hatchery
work.

References
Chaitanawisuti N. & Kritsanapuntu A. (1997) Effects of
stocking density and substrate presence on growth and
survival of juvenile spotted babylon, Babylonia areolata
Link, 1807 (Neogastropoda: Buccinidae). Journal of Shell­
fish Research 16, 429 433.
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