Collaboration for Agriculture & Rural Development: Technical and economic feasibility of applying the Better Management Practices (BMP) to household aquaculture in Vietnam - MS 8 " doc

1

Ministry of Agriculture and Rural Development

COLLABORATION FOR AGRICULTURE
AND RURAL DEVELOPMENT (CARD)


002/05 VIE
Technical and economic feasibility of applying
the Better Management Practices (BMP) to
household aquaculture in Vietnam


MS 8: Technical Report
Environmental and Economic Evaluation of Better
Management Practices for Shrimp Culture in Vietnam

Nguyen Xuan Suc
1
, Dinh Van Thanh
1
, Bui Kien Cuong
1
,
Virginia Mosk
2

and Elizabeth Petersen
2



1
Research Institute for Aquaculture No 1 (RIA1), Tu Son, Bac Ninh
2
The University of Western Australia, 35 Stirling Hwy, NEDLANDS WA 6907
§
Corresponding Author: , Ph/Fax: +61 8 9332 8310


- 2008 -

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
2
Acknowledgements
The authors would like to sincerely thank the Collaboration for Agriculture and Rural
Development (CARD) Programme for funding this research. We would also like to
thank the following institutions for their support:
• The Research Institute for Aquaculture Number 1 in Vietnam,
• The University of Western Australia,
• The Center for Fisheries Extension in Ha Tinh, Nghe An, and Thua Thien-Hue,
• Vietnam’s National Fisheries Quality Assurance and Veterinary Directorate
(NAVIQAVED), and
• The nine farming households for participating in the trial:
o Phan Ngan,
o Hau Van Anh,

o Tran Dinh Van,
o Cao Xuan Hoa,
o Le Van Tuan,
o Dinh Van Dung,
o Nguyen Hong Quyen,
o Nguyen Ngoc Hanh, and
o Hoang Xuan Kien.


Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
3
Executive Summary

The aim of the report is to provide an initial investigation into whether Better
Management Practices (BMPs) can be adopted by Vietnamese shrimp farmers to
reduce the environmental and food safety risks of shrimp production, while ensuring
the farms remain economically viable. It includes analysis of data from in-field
measurements and laboratory analysis of key environmental quality parameters at
different locations within shrimp farming systems that implemented BMPs, including
water in inlet canals before it enters cultivation ponds, water within the cultivation
ponds themselves, and water in outlet canals once it has exited the pond. The same
in-field measurements and laboratory analysis is conducted for shrimp ponds of nine
farming households implementing BMPs (three each in Nghe An, Ha Tinh and Thua
Thien-Hue). Chemical and microbial analysis is also conducted on shrimp produced in
these nine households, and the economic viability of their operations is assessed.

While trials need to be conducted on a larger number of farms over a longer time
period for the findings to be presented with confidence, initial results in this report
suggest that implementation of BMPs are generally effective at controlling

environmental water quality, and chemical and microbial outbreaks. Moreover, the
profitability of farms using these practices are just as cost-effective as farms that do
not use BMPs (the benefit cost ratio of BMP and non-BMP farms are similar). Hence,
widespread adoption of these practices in Vietnam is not likely to have a detrimental
impact on profitability of farming enterprises. Rather, it is likely to have a positive
impact if export markets can be ensured or possibly expanded with product
certification.

Specific key findings
1. Analysis of environmental water sampling showed that, on average, a
number of parameters were within recommended limits for maximising
shrimp production, including: salinity and water temperature (although
significant variation outside recommended limits was reported through
time for these two parameters), pH, ammonia, alkalinity, nitrogen
dioxide and hydrogen sulphide,
2. Transparency readings were found to be slightly problematic being
mostly above the optimal range which showed a difficulty in
establishing good phytoplankton blooms. Temperature was sometimes
found to be lower than recommended levels for optimal production,
3. The one problematic environmental parameter was dissolved oxygen –
with levels being consistently below recommended levels for
maximised production, especially in the morning. Moreover, low
dissolved oxygen levels in output channels have the potential to be
hazardous to significant varieties of fish fauna. Pond aeration prior to
discharge is likely to negate these impacts, although the cost impacts
to the shrimp enterprise needs to be assessed,
4. Chemical and microbial analysis found no or negligible levels of
chemicals or microbes harmful to shrimp (for production or food
safety) or the environment,
Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam

Research Institute for Aquaculture No 1 & The University of West Australia
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5. Total costs of half-hectare shrimp operations is approximately 55
million VND (approximately USD3,400 at the time of writing). These
costs are dominated by feeding (51%). There is significant variation in
costs across farms,
6. The average production is just over 1 tonne/half-hectare operation,
valued at 76 million VND (approximately USD4,700 at the time of
writing). This is also very variable across shrimp operations,
7. The average price received for the shrimp was 73,000VND per shrimp,
although higher prices were received for larger shrimp compared with
the small shrimp (by weight),
8. Profit was approximately 21 million VND (approximately USD1,300 at
the time of writing), compared with 8 million VND for non-BMP
farmers. The average Benefit Cost Ratio was approximately 1.3, on par
with non-BMP farmers. This suggests that the study farms invested
significantly more funds into their operations, than the average non-
BMP farmer,
9. If environmental water quality is contained within recommended limits,
and chemical and microbial outbreaks are avoided, then the major
determinant of profit was feeding. The most cost-effective farms were
those that invested heavily in feeding the shrimp.
10. There are significant opportunities for increased capitalisation of
shrimp enterprises. Significant growth in Vietnam’s shrimp aquaculture
industry has the potential to be sustained in the medium-term.


Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
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Table of Contents

Acknowledgements 2
Executive Summary 3
1. Introduction 6
2. Methodology 8
3. Environmental Quality of Shrimp Aquaculture Systems 10
3.1 Transparency 10
3.2 Salinity 11
3.3 pH 12
3.4 Dissolved oxygen (DO) 12
3.5 Water temperature 13
3.6 Ammonia (NH
3
) 14
3.7 Alkalinity 15
3.8 Nitrite 15
3.9 Sulphides 16
3.10 Key findings 17
4. Household Shrimp Production 18
4.1 General information on household operations 18
4.2 Environmental water quality data 19
4.3 Shrimp produt quality analysis (chemical and microbial) 22
4.4 Costs of production 23
4.5 Production volume and value 27
4.6 Profit and Benefit Cost Ratio 29
5. Discussion and Conclusions 31
5.1 Environmental water quality parameters 31
5.2 Shrimp production and profitability 32
5.3 Summary comments 33

Bibliography 34
Appendix 1: Better Management Practices 35
Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
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1. Introduction

Household shrimp production is the predominant form of coastal aquaculture in
Vietnam. In 2006, approximately 459,000 tonnes of shrimp was produced comprising
12% of total fisheries production in Vietnam (USDAFAS 2007). Approximately 34% of
shrimp production (158,000 tonnes) was exported at a value of USD1.46billion.
Shrimp production is increasing, with an average of 13% growth experienced each
year from 2000 to 2006 (USDAFAS 2007). Prices have remained steady such that the
growth in the value of shrimp production is similar to the growth in volume.

Approximately 70% of shrimp production (by volume) is produced through
aquaculture operations, which comprises approximately 24% of total aquaculture
production by volume but 71% by value (Fistenet 2007). Aquaculture production of
shrimp experienced an average of 26% growth between 2001 and 2006, compared
with 2% growth in the wild-caught sector.

In recent years, residues and contaminants have been detected in exported shrimp,
with devastating results in markets. In 2003, five consignments from Thua Thien-Hue
(TT-Hue) province to the European Union were destroyed or returned because of the
presence of residues, and a far larger quantity from all north central provinces were
similarly treated in 2004. Low standards of education, limited farm capital and
minimal opportunities for capacity-building amongst households have resulted in
inappropriate farm practices, which have caused degradation of the environment,
declines in water quality, loss of farm resources and disease outbreaks. As a
consequence, the livelihood of many of these farmers is threatened.

The loss of production, negative environmental and socio-economic impacts, and
food safety concerns have provided impetus for the development and extension of
better management practises (BMP) for household shrimp farms. BMPs have been
used in many countries to implement the more general principles of responsible
shrimp farming (FAO 2005). They can be defined as farm and local-level practices
aimed at enhancing efficiency, productivity, mitigating negative environmental and
socio-economic impacts, and suppling products that meet requirements of food
safety. BMPs are voluntary and are becoming widely used as an important strategy to
enhance the marketability of aquaculture product.

A number of projects have contributed to the development of practical BMPs for
shrimp farming in Vietnam (e.g. a DANIDA-funded (Danish International
Development Agency) SUMA/NACA project (Support to Brackish Water and Marine
Aquaculture/Network of Aquaculture Centre in Asia-Pacific), and a NAFIQAVED
(National Fisheries Quality Assurance and Veterinary Directorate) pilot project - see
Appendix 1 for the list of BMP protocols). These projects have proposed specific BMPs
and have conducted some small-scale testing of these BMPs. Their findings have not
yet been widely disseminated among producers and BMP implementation is still
limited. This is due to a number of financial, social, technical and economic feasibility
constraints. Small-scale household shrimp farms are extremely diverse and
fragmented, and their capacities to adopt BMP are hampered by lack of awareness,
capital constraints and lack of perceived incentive. The benefits of applying BMP to
Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
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7
household farms remain to be fully investigated. However, experience in Thailand,
India and Bangladesh has shown that small-scale farmers who applied BMPs made
gains in efficiency, productivity and quality (SUMA, 2004).

This report is one output of a project jointly funded by the Australian Agency for
International Development (AusAID) and the Vietnam Ministry of Agriculture and
Rural Development (MARD) through the Collaboration for Agriculture and Rural
Development Programme (CARD). The aim of the report is to provide an initial
investigation into whether BMPs can be adopted by Vietnamese shrimp farmers to
reduce the environmental and food safety risks of shrimp production, while ensuring
the farms remain economically viable. It presents the results of environmental and
economic evaluation of BMP trials in three provinces of Vietnam (Ha Tinh, TT-Hue
and Nghe An). The evaluation includes analysis of water quality as it enters and
leaves shrimp ponds, product quality data, and economic assessment of household
incomes for those participating in the BMP trials.

The report proceeds with a methodology (Section 2), an analysis of environmental
quality parameters of shrimp aquaculture systems (including the potential impact of
shrimp production on food safety and the environment) (Section 3), and an analysis
of household shrimp production (including food safety, production and profitability
aspects of households implementing BMPs) (Section 4). The report finishes with a
discussion and conclusion regarding the initial assessment of the cost-effectiveness of
BMP adoption in reducing environmental and food safety risks (Section 5).

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
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2. Methodology

Data collection was conducted over a five month period, March to July 2007, in three
provinces; Ha Tinh, Nghe An, and Thua Thien-Hue (TT-Hue) (see Figure 1).

Figure 1: Vietnamese provincial map indicating the location of the three project provinces

Data was collected by three sources:
1. Extension officers. These data include in-field measurements and laboratory
analysis of key environmental quality parameters at different locations within
the project site. Data is presented for inlets (water in inlet canals before it
enters the ponds), outlets (water in outlet canals once it has exited the pond),
and within the ponds themselves. Readers are referred to Ha and Suc (2007)
for more information on project sampling sites.
2. Farmer households. These data include in-field measurements of key
environmental quality, production and economic parameters collected by nine
different shrimp farmers within the project site.
3. NAVIQAVED officers (Vietnam’s National Fisheries Quality Assurance and
Veterinary Directorate). NAVIQAVED controls food safety and veterinary
services for seafood products in Vietnam. They provide chemical and
microbiological analyses of shrimp produced by the nine farmer households
during the trial period.

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
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In-field measurements included:
• pH: measured with a portable pH meter (YSI 52)
• Salinity: use of refractometer (Spec T2000)
• Dissolved Oxygen (DO): measured with an oxygen meter (YSI 52)
• Temperature (
o
C): measured with a digital thermometer (Thermo 100)
• Transparency (cm): measured with Secchi disk

The running river water was used as a supply source for in-field laboratory analysis.
Samples were collected using a peristaltic pump with two heads, were kept cool with

ice, and then analyzed immediately upon reaching the laboratory. All analysis
followed standard methods (Alpha 1998), and included:
• Alkalinity (mg/l),
• Ammonia (mg/l),
• Nitrite (mg/l), and
• Sulphide (mg/l).

In-field measurements and laboratory analyses were conducted by Extension Officers
and the nine farming households (with assistance from the Vietnamese research
team). The nine farming households also completed a shrimp culture diary to collate
production and economic information. The Vietnamese project team took the shrimp
product samples from the nine households to Vietnam's NAVIQAVED for shrimp
product quality analysis (including chemical and microbial analysis).

The Vietnamese and Australian partners (Research Institute for Aquaculture No.1 and
the University of Western Australia) collaborated in the data analysis and report
writing. Three Vietnamese project partners visited Perth in December 2007 to
collaborate with the Australian project partners to conduct initial data analysis,
discussion and planning. The analysis and report was finalised through email contact.

Project team
The Vietnam-based project team comprised:
¾ Mr Nguyen Xuan Suc, Project Leader,
¾ Dr Dinh Van Thanh, and
¾ Mr Bui Kien Cuong.

The Australian-based project team comprised:
¾ Dr Elizabeth Petersen – Adjunct Senior Lecturer, the University of Western
Australia, and Applied Economist, Advanced Choice Economics Pty Ltd,
¾ Ms Virginia Mosk, MSc – Technical Aquaculture Consultant to The University of

Western Australia, and
¾ Associate Professor Steven Schilizzi – The University of Western Australia.






10
3. Environmental Quality of Shrimp Aquaculture
Systems

This section presents data collected by Extension Officers on nine environmental
water quality parameters, which was taken at approximately two week intervals over
a four month period from March/April – June/July 2007 (the exact time period differs
across provinces). These tests were done at three demonstration farms. Testing was
conducted on water within ponds, as well as on water before it enters the ponds
(inlets) and after it has exited the ponds (outlets). Key findings are presented at the
end of this section (Sub-section 3.10).

3.1 Transparency
It is recommended that transparency (Secchi disc visibility) remain between 25 and
40cm for maximum production (Boyd 1990). If transparency is less than 25cm and
the pond is too turbid with phytoplankton, this may create problems with dissolved
oxygen. If the reading is greater than 40cm then the phytoplankton is too scarce.

Transparency readings were found to be above the maximum level at the start of the
production period in ponds of all three provinces, decreasing to within recommended
levels half way through the season in Ha Tinh and Nghe An (Figure 2). While
transparency readings were higher than recommended in the inlets and outlets of all

provinces (with the exception of the outlets in TT-Hue), transparency is considered to
be an indication of pond condition and phytoplankton density, and is therefore less
important in the inlet and outlet channels.

Transparency levels in the inlet and outlet are unlikely to have an impact on the
environment, or affect food safety, as it is purely an optimal range for the best
growth of the shrimp. Plankton blooms favour greater shrimp production by
stimulating the growth of shrimp food organisms and it also limits the visibility of the
shrimp from predatory birds, thus reducing stress to the target species allowing them
to roam and feed, and develop more quickly.

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
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Ha Tinh - Transp are ncy
20
30
40
50
60
70
80
date
cm
Inlet
Outlet
Ponds
Hue - Trans
p
arenc

y
20
30
40
50
60
70
80
cm
Inlet
Outlet
Ponds

Nghe An - Transparency
20
30
40
50
60
70
80
cm
Inlet
Outlet
Ponds

Figure 2: Transparency levels in inlets, outlets and ponds

3.2 Salinity
There is very little difference in salinity levels between water sources in any

provinces (Figure 3). It is recommended that for maximum production, salinity levels
remain between 15 and 25%
o (Boyd 1990). Salinity levels remained between this
range in Nghe An, but increased to 27%
o by the end of the cultivation period in Ha
Tinh, and dropped below this range mid-season in TT-Hue due to heavy rainfall which
is common for that time of year. Salinity levels in the inlet and outlet during and at
the end of the trial is unlikely to have an impact on the environment or food safety.
Ha and Suc (2007) indicates a range of 13-24%
o for the three areas prior to
stocking.

Ha Tinh - Salinity
11
16
21
26
date
o/00
Inlet
Outlet
Ponds
Hue - Salinity
11
16
21
26
o/00
Inlet
Outlet

Ponds

Nghe An - Salinity
11
16
21
26
o/00
Inlet
Outlet
Ponds

Figure 3: Salinity levels in inlets, outlets and ponds

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
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3.3 pH
It is recommended that for maximum shrimp production, pH remain between 7.5 and
8.5 (Boyd 1990). The pH of the culture pond was consistently within this range
throughout the season in all provinces (Figure 4). pH levels were lower than
recommended in inlets and outlets in Nghe An and in the inlets in Ha Tinh, although
this does not have an impact on shrimp production if pH levels are correct within the
ponds themselves.
pH levels in inlet and outlet canals during and at the end of the trial is unlikely to
have an impact on the environment or food safety. The MS-3 baseline data report
(Ha and Suc 2007) indicates a range of 6-8.30
for the three areas prior to stocking.

Ha Tinh - pH

5.5
6
6.5
7
7.5
8
8.5
date
pH
Inlet
Outlet
Ponds
Hue - pH
5.5
6
6.5
7
7.5
8
8.5
pH
Inlet
Outlet
Ponds

Nghe An - pH
5.5
6
6.5
7

7.5
8
8.5
pH
Inlet
Outlet
Ponds

Figure 4: pH levels in inlets, outlets and ponds

3.4 Dissolved oxygen (DO)
Generally, dissolved oxygen levels are highest in the inlets, and lowest in the outlets
(Figure 5). Dissolved oxygen of the culture pond at Ha Tinh and TT-Hue sat above
5.5 mg/l (above 5 mg/l being optimal) even though the outlet pond readings did drop
below 4.5 mg/l. At Nghe An, dissolved oxygen dropped below 5mg/l for most of the
season and ended at around 3.75 mg/l. Despite the dissolved oxygen of the outlet
pond in Ha Tinh dropping to around 2.75 mg/l at the end of the season, the culture
pond stayed at a stable 5.5 mg/l. As shrimp spend most of their time on the pond
bottom, the mud/water interface and its oxygen content is very important. Almost all
muds are devoid of oxygen below a depth of a few centimetres because of poor water
circulation and microbial activity within the mud. Maintenance of oxygenated
conditions at the mud surface is particularly important in shrimp ponds as oxygen is
needed for shrimp and food organism respiration, it promotes microbial degradation
of organic matter, and prevents the release of toxic, reduced substances such as
hydrogen sulphide and nitrite (Boyd 1990). If the readings where taken at the same
position each time in the culture ponds it may be that there were other stagnant
areas of the pond, which were not aerated and circulated properly, hence causing an
overall reduction of oxygen in the system. DO at these levels are unlikely to affect
food safety, however DO levels in outlets that fall lower than 5mg/l may have an
impact on the environment, and plants and animals in the surrounding aquatic

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
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ecosystem. Under normal stream conditions 3.0mg/l or less, of DO is regarded as
hazardous for a significant variety of fish fauna (Ellis 1937).
Ha Tinh - DO
2.5
3.5
4.5
5.5
6.5
7.5
date
mg/l
Inlet
Outlet
Ponds
Hue - DO
2.5
3.5
4.5
5.5
6.5
7.5
mg/l
Inlet
Outlet
Ponds

Nghe An - DO

2.5
3.5
4.5
5.5
6.5
7.5
mg/l
Inlet
Outlet
Ponds

Figure 5: Dissolved oxygen levels in inlets, outlets and ponds

3.5 Water temperature
There was little difference in the water temperature between water sources in any of
the provinces (Figure 6). For shrimp production, it is recommended that the
temperature remains between 25 and 33
o
C for maximum production. Temperature
remained within this range in all provinces. Temperature increased over the season
in all provinces, and experienced significant increases mid-season in TT-Hue and
Nghe An corresponding to the drop in salinity and pH of the water.

As temperature levels both in the inlet and outlet channels effectively mirriored the
temperature in the ponds, and were similar to baseline readings (Ha and Suc 2007),
it is highly unlikely that there would be an impact on the surrounding environment.
Water temperature would only affect food safety if the product was harvested and
not put on ice immediately and handled properly throughout the packaging and
transporting process. The temperature of the ponds alone would have no effect.

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
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Ha Tinh - Temperature
24
26
28
30
32
34
date
oC
Inlet
Outlet
Ponds
Hue - Temperature
24
26
28
30
32
34
oC
Inlet
Outlet
Ponds

Nghe An - Temperature
24
26

28
30
32
34
oC
Inlet
Outlet
Ponds

Figure 6: Water temperature levels in inlets, outlets and ponds

3.6 Ammonia (NH
3
)
Ammonia levels were consistently low in all water sources and provinces throughout
the season (Figure 7). Levels were below 0.1mg/l in all sources, which is the
maximum recommended level for Vietnam (internationally, Chin & Chen (1987)
consider 0.13mg/l of ammonia to be a safe level for shrimp pond conditions).
Generally, ammonia levels were found to be higher in the outlets than in the ponds
and inlets. Levels of ammonia in the outlet channels were not significantly high and
would be unlikely to impact the environment or food safety standards. Ammonia is
more toxic when dissolved oxygen concentration is low, however with increasing
carbon dioxide (which occurs when DO is low) the toxicity of ammonia decreases
(Boyd 1990).

Ha Tinh - NH3
0
0.2
0.4
0.6

0.8
date
mg/l
Inlet
Outlet
Ponds
Hue - NH3
0
0.02
0.04
0.06
0.08
mg/l
Inlet
Outlet
Ponds

Nghe An - NH3
0
0.02
0.04
0.06
0.08
mg/l
Inlet
Outlet
Ponds

Figure 7: Ammonia levels in inlets, outlets and ponds

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
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3.7 Alkalinity
Alkalinity averaged approximately 85mg/l in all water sources, although it increased
significantly to approximately 100mg/l in Ha Tinh during the end of the data
collection period (Figure 8). This increase corresponds to a drop in temperature,
salinity and pH. Alkalinity in all water sources generally remained within the safe
range of 80-120 mg/l. Alkalinity is defined as the sum of exchangeable bases
reacting to neutralise acid when an acid is added to water. Alkalinity plays two
important roles in water. Bicarbonates, and carbonates to a lesser degree, are a
storehouse of carbon needed in photosynthesis for phytoplankton growth. They also
constitute the major buffering system to reduce fluctuations in pH. Alkalinity levels
in outlets and inlets at all times during the trial was unlikely to have any impact at all
on the environment or affect food safety.

Ha Tinh - Alka linity
60
80
100
120
date
mg/l
Inlet
Outlet
Ponds
Hue - Alkalinity
60
80
100

120
mg/l
Inlet
Outlet
Ponds
Nghe An - Alkalinity
60
80
100
120
mg/l
Inlet
Outlet
Ponds

Figure 8: Alkalinity levels in inlets, outlets and ponds

3.8 Nitrite
There are significant differences in nitrite levels across provinces and water sources
(Figure 9). It is recommended that nitrite levels remain below 0.30mg/l to maximise
shrimp production. Whilst sub-lethal concentrations of nitrite increases the
susceptibility of fish to bacterial diseases (Hanson & Grizzle, 1985), nitrite levels were
significantly lower than this level for all water sources in TT-Hue, and generally for
inlets and ponds in Ha Tinh and Nghe An. As there are many factors which affect the
nitrite toxicity in fish and shrimp ponds (eg. chloride concentration, pH, animal size,
previous exposure, nutritional status, infection and dissolved oxygen concentration
(Schwedler et al. 1985)), it is difficult to pinpoint one variable. However, attention to
dissolved oxygen is again highlighted as important.

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
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Ha Tinh - Nitrate
0
0.05
0.1
0.15
0.2
0.25
0.3
date
mg/l
Inlet
Outlet
Ponds
Hue - Nitrite
0
0.05
0.1
0.15
0.2
0.25
0.3
mg/l
Inlet
Outlet
Ponds

Nghe An - Nitrite

0
0.05
0.1
0.15
0.2
0.25
0.3
mg/l
Inlet
Outlet
Ponds

Figure 9: Nitrite levels in inlets, outlets and ponds

3.9 Sulphides
It is recommended that sulphides remain below 0.2mg/l for maximum production.
Sulphide levels in TT-Hue were consistently and significantly below this level for all
water sources in TT-Hue, and for inlets and ponds in Ha Tinh and Nghe An (Figure
10). Sulphide levels were higher than recommended in the outlets in Nghe An, and in
Ha Tinh at the beginning of the season. Toxic amounts of hydrogen sulphide block
the electron transport system and stops oxidative respiration. Blood lactate
concentrations also increase and anaerobic glycolysis is favoured over aerobic
respiration, suggesting that the toxic effect is hypoxia. Therefore, increased levels of
dissolved oxygen are desirable (Boyd, 1990). Hydrogen sulphide toxicity is also more
common in acidic environments as pH decreases. As hydrogen sulphide is toxic at low
concentrations and egg survival and fry development of fish can be limited by
0.006mg/l H
2
S, impact on the environment should be monitored. If the pond water
can be aerated prior to discharge this would minimise the environmental impact of

H
2
S. At the levels reflected in these data food safety is not a concern.
Ha Tinh - Sulphide
0
0.01
0.02
0.03
0.04
date
mg/l
Inlet
Outlet
Ponds
Hue - Sulphide
0
0.01
0.02
0.03
0.04
mg/l
Inlet
Outlet
Ponds

Nghe An - Sulphides
0
0.01
0.02
0.03

0.04
mg/l
Inlet
Outlet
Ponds

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
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Figure 10: Sulphide levels in inlets, outlets and ponds

3.10 Key findings
1. Five environmental water parameter readings were within the recommended
range (for maximum production) in all provinces:
a. Alkalinity,
b. Ammonia,
c. Nitrite,
d. pH, and
e. Water temperature,
2. Dissolved oxygen was lower than recommended in Nghe An,
3. Salinity was lower than recommended in TT-Hue, and higher than
recommended in Ha Tinh,
4. Sulphides were within the recommended range for all ponds, although higher
than recommended for outlets in Ha Tinh and Nghe An,
5. Transparency was high at the beginning of the cultivation period in all
provinces, but fell to within the recommended range in Ha Tinh and Nghe An
towards the end of the period,
6. An increase in alkalinity in Ha Tinh corresponded to drop in temperature, pH
and salinity, and
7. Environmental quality data analysis shows that it is unlikely that the shrimp

aquaculture systems tested will have an adverse effect on the environment or
food safety. One exception to this is dissolved oxygen levels, which were low
in the output channels and my be hazardous for fish fauna. Low dissolved
oxygen also increases the toxicity of nitrites and sulphides in outlet channels.
Pond water aeration prior to discharge is likely to negate these impacts.


Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
18
4. Household Shrimp Production
Data and analysis on household shrimp production is presented in the following six
sub-sections:
1. General information on household operations,
2. Environmental and water quality data,
3. Chemical and microbial analysis,
4. Costs of production,
5. Production volume and value, and
6. Profit and Benefit Cost Ratio.

4.1 General information on household operations
Nine households participated in the BMP trials, three from Thua Thien-Hue (TT-Hue)
(households 1 to 3 in Table 1), three from Nghe An (households 4 to 6 in Table 1)
and three from Ha Tinh (households 7 to 9 in Table 1). The average size of the
shrimp culture ponds was 0.44ha, ranging from 0.25ha to 0.68ha. This average pond
size is smaller than the average of non-BMP shrimp farmers in the same provinces
(0.69ha) (Thanh et al. 2007).

Table 1: Household name, location, pond area and culture type
Location of household

Area of culture
pond (ha)
Stocking
density
(shrimp/m
2
)
Culture type
1 Phongchanh, Vinhhung, TT-Hue 0.68 7.9 Improved-extensive
2 Phongchanh, Vinhhung, TT-Hue 0.36 13.9 Improved-extensive
3 Phongchanh, Vinhhung, TT-Hue 0.50 10.0 Improved-extensive
4 Hunghoa, Hunghoa, Nghe An 0.25 24.0 Semi-intensive
5 Hunghoa, Vinh, Nghe An 0.45 22.2 Semi-intensive
6 Hunghoa, Vinh, Nghe An 0.50 10.0 Improved-extensive
7 Hongha, Thachha, Ha Tinh 0.50 18.0 Semi-intensive
8 Lienha, Thachha, Ha Tinh 0.50 20.0 Semi-intensive
9 Lienha, Thachha, Ha Tinh 0.25 24.0 Semi-intensive
Average 0.44 16.7

Four of the nine shrimp farmers who participated in the trials also have ‘containing
ponds’ which are used for water conditioning and processing. These ponds average
0.19ha (ranging from 0.10 to 0.25ha).

The average stocking density was 16.7 shrimp/m
2
, which is almost double that of
non-BMP households where the stocking density is 8.4 shrimp/m
2
(Thanh et al.
2007).

Culture type is defined by stocking rate according to the following guide:
• < 8 shrimp/m
2
– Extensive
Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
19
• 8 – 15 shrimp/m
2
– Improved extensive
• 15 – 25 shrimp/m
2
– Semi-intensive
• > 25 shrimp/m
2
– Intensive

The households who participated in the farm trials are either improve-extensive or
semi-intensive farmers. All farmers in TT-Hue are improved-extensive farmers. All
other farmers are semi-intensive except for one farmer in Nghe An.

4.2 Environmental water quality data
This section presents data on environmental water quality parameters collected by
household members. They are the same nine parameters as measured by Extension
Officers for the shrimp systems as presented in Section 3, and are located in the
same three provinces. Table 2 presents average, minimum and maximum water
quality readings from a 10-17 week culture period from March/April to June/July
2007 (the exact timing of the readings depends on the farm).

4.2.1. Transparency
Although the average transparency reading for all households was approximately
37cm, within the recommended range of 25 – 40cm for maximum production, almost
all ponds had higher than recommended maximum levels, and one pond also fell
below the recommended minimum of 25cm.

Data was missing from ponds 6, 7 & 8, and patchy data for 4, 5 & 9, however farms
from the other ponds noted in detail water colour and corrective measures taken if
the colour changed from ideal green to strong green. Pond 3 in TT-Hue seemed to
have the most consistent colour from green to strong green and to yellow. These
transparency levels are unlikely to have an impact on the environment, or affect food
safety, as it is purely an optimal range for the best growth of the shrimp.

4.2.2 Salinity
The average salinity reading for all households was approximately 19%
o, which is
within the recommended range of 15-25%
o for maximum production. Salinity was
low in TT-Hue, with two farmers having lower than recommended salinity levels
(even though it may be expected that warmer ambient air temperatures in this

region would encourage evaporation and therefore increase salinity levels). Overall,
salinity was higher in Ha Tinh and Nghe An, with higher than recommended readings
on some of the ponds in those areas. These salinity levels are unlikely to have an
impact on the environment or food safety. Ha and Suc (2007) indicate a range of 13-
24%
o for the three areas prior to stocking.

4.2.3 pH
pH in the mornings (average 7.93) and evenings (average 8.10) did not venture

greatly outside the optimum range of 7.50 – 8.50 for maximum production.
Generally, pH was found to be slightly higher in the evenings than in the mornings.
pH levels are unlikely to have an impact on the environment or food safety. Ha and
Suc (2007) indicates a range of 6-8.30
for the three areas prior to stocking.

Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
20
4.2.4 Dissolved oxygen levels seemed to be a widespread problem with a number
of minimum and maximum readings falling below the acceptable 5.00mg/l, especially
in the mornings, and will thus not enhance maximum growth of this species. DO at
these levels are unlikely to affect food safety, however DO levels in outlets that fall
lower than 5mg/l may have an impact on the environment, and plants and animals in
the surrounding aquatic ecosystem. Under normal stream conditions 3.0mg/l or less,
of DO is regarded as hazardous for a signicant variety of fish fauna (Ellis 1937).

4.2.5 Temperature readings were consistently between the optimum of 25–33
o
C for
maximum production. Ponds in Ha Tinh and Nghe An had maximum temperatures
higher than the recommended temperatures. As the temperatures did not deviate
greatly from the ambient, it is highly unlikely that there would be an impact on the
surrounding environment. Water temperature would only affect food safety if the
product was harvested and not put on ice immediately and handled properly
throughout the packaging and transporting process. The temperature of the ponds
alone would have no effect.

4.2.6 Ammonia (NH
3

), almost all readings fell within the safe range for production
and environment of 0.00–0.10 mg/l. Levels of ammonia were not significantly high
and would be unlikely to impact the environment or food safety standards. Ammonia
is more toxic when dissolved oxygen concentration is low, however with increasing
carbon dioxide (which occurs when DO is low) the toxicity of ammonia decreases
(Boyd 1990).

4.2.7 Alkalinity readings were consistently between the optimal range of 80–
120mg/l. Two farms each in TT-Hue and Nghe An dropped below the optimal range,
but it is not expected that this would impact shrimp production, and was unlikely to
have any impact at all on the environment or affect food safety.

4.2.8 Nitrogen Dioxide (NO
2
) and Hydrogen Sulphide (H2S) levels were all
within the safe range throughout the season and in all ponds, and are unlikely to
have any impact on the environment or food safety





21
Table 2: Environmental water quality parameter of households

Transparency
(cm)
Salinity
(%o)
pH

(AM)
pH
(PM)
DO mg/l
(AM)
DO mg/l
(PM)
Temp
o
C
(AM)
Temp
o
C
(PM)
NH
3
(mg/l)
Alkalinity
(mg/l)
NO
2
(mg/l)
H
2
S
(mg/l)
Standard Max 40.00 25.00 8.50 8.50 33.00 33.00 0.10 120.00 0.25 0.02
Optimal
range for

Vietnam
Standard Min 25.00 15.00 7.50 7.50 5.00 5.00 25.00 25.00 0.00 80.00 0.00 0.00
Average household data 36.81 19.14 7.93 8.10 4.56 5.42 28.90 31.18 0.04 88.30 0.02 0.00
Max actual 41.43 19.57 8.46 8.36 5.61 5.49 32.14 34.14 0.01 115.00 0.02 0.00
Min actual 30.00 15.79 8.10 8.00 5.16 4.70 25.71 30.57 0.00 86.00 0.00 0.00
Pond 1
TT-Hue
Average 35.16 17.80 8.29 8.18 5.41 5.26 30.06 32.09 0.00 97.63 0.01 0.00
Max 50.71 15.57 8.17 8.50 5.21 6.36 29.21 32.93 0.07 95.00 0.03 0.01
Min 34.29 12.43 7.74 8.00 4.38 5.71 26.86 29.86 0.00 71.60 0.00 0.00
Pond 2
TT-Hue
Average 41.57 14.33 7.92 8.19 4.74 6.06 28.41 31.14 0.02 84.35 0.01 0.00
Max 54.29 15.71 8.10 8.50 5.07 6.21 29.00 34.71 0.05 100.00 0.03 0.00
Min 37.14 12.00 7.64 7.94 4.71 5.92 27.36 30.07 0.00 67.50 0.00 0.00
Pond 3
TT-Hue
Average 42.14 14.18 8.45 8.15 4.93 6.07 28.21 31.03 0.02 85.43 0.01 0.00
Max 49.17 22.00 8.25 8.45 6.30 8.50 32.00 39.70 0.01 90.00 < 0.3 0.02
Min 25.00 15.00 6.90 7.23 3.75 4.13 25.63 26.25 0.01 71.60 < 0.3 0.00
Pond 4
Nghe An
Average 33.18 18.49 7.54 7.83 4.68 5.95 28.58 31.67 0.01 80.57 < 0.3 0.01
Max 56.67 19.00 8.45 8.65 5.00 5.30 33.00 33.50 0.01 90.00 <0.3 0.02
Min 30.00 15.00 7.65 7.90 2.00 3.00 25.00 25.25 0.00 71.60 <0.3 0.00
Pond 5
Nghe An
Average 38.01 17.75 8.03 8.23 3.69 4.44 28.90 29.68 0.01 76.63 <0.3 0.01
Max 62.14 27.21 8.33 8.60 4.29 4.29 32.50 35.17 1.08 110.00 < 0.3 0.00
Min 30.00 20.00 7.50 7.75 3.14 3.14 23.57 25.29 0.00 80.00 < 0.3 0.00

Pond 6
Nghe An
Average 38.75 21.38 7.99 8.37 3.95 3.95 27.87 29.82 0.15 89.50 < 0.3 0.00
Max 40.00 27.00 7.77 8.06 5.40 6.00 30.50 34.25 0.08 110.00 0.05 0.02
Min 27.50 24.00 7.54 7.77 4.00 5.50 28.00 29.00 0.01 89.50 0.01 0.01
Pond 7
Ha Tinh
Average 35.06 25.60 7.67 7.93 4.60 5.70 29.63 31.85 0.05 99.83 0.03 0.01
Max 50.00 31.00 8.14 8.43 n.a. n.a. n.a. n.a. 0.09 120.00 0.10 0.02
Min 10.00 22.00 7.76 7.99 n.a. n.a. n.a. n.a. 0.01 89.50 0.01 0.01
Pond 8
Ha Tinh
Average 30.00 24.83 7.94 8.23 n.a. n.a. n.a. n.a. 0.06 101.18 0.06 0.01
Max 62.50 20.50 8.10 8.45 5.00 8.30 34.00 36.00 0.09 90.00 n.a. 0.01
Min 25.00 15.00 7.11 7.39 3.60 4.25 25.68 26.25 0.00 70.00 n.a. 0.00
Pond 9
Ha Tinh
Average 37.38 17.90 7.49 7.79 4.49 5.92 29.58 32.14 0.02 79.63 n.a. 0.00
Note: Bold figures indicate that the value falls outside the optimal range for Vietnam.
n.a. = not available




22
4.3 Shrimp produt quality analysis (chemical and microbial)
This sub-section presents data collected by officials from Vietnam’s National Fisheries
Quality Assurance and Veterinary Directorate (NAFIQAVED) – the agency which
controls food safety and veterinary services for seafood products. The data includes
chemical and microbiological analysis (Table 3). Results indicate non-existent

amounts of almost all compounds, except a negligible positive result for Furazolidone
(AOZ) in ponds 8 and 9 (Ha Tinh province) and Salmonella in ponds 2 and 3 (TT-Hue
province). While the Salmonella detected is of most concern, there is little likelihood
that it would impact on the health of the shrimp, nor is it likely to affect food safety
or off-side environmental conditions.

Table 3: Chemical and microbial analysis of shrimp products.
Chemical analysis Microbial analysis

CAP
(µg/kg)
AOZ
(µg/kg)
AMOZ
(µg/kg)
AHD
(ppb)
SEM
(ppb)
TPC E. coli
Salmon-
ella
V.
cholerae
Pond 1
TT-Hue
ND ND ND ND ND 5.5*100,000 Neg Neg Neg
Pond 2
TT-Hue
ND ND ND ND ND 6.5*10,000 Neg Pos Neg

Pond 3
TT-Hue
ND ND ND ND ND 6.5*10,000 Neg Pos Neg
Pond 4
Nghe An
ND ND ND ND ND 2.7*10,000 <10 Neg Neg
Pond 5
Nghe An
ND ND ND ND ND 1.2*100,000 <10 Neg Neg
Pond 6
Nghe An
ND ND ND ND ND 2.9*100,000 <10 Neg Neg
Pond 7
Ha Tinh
ND ND ND ND ND 4.1*10,000 <10 Neg Neg
Pond 8
Ha Tinh
ND Pos ND ND ND 3.7*10,000 <10 Neg Neg
Pond 9
Ha Tinh
ND Pos ND ND ND 4.3*10,000 <10 Neg Neg
Coding: CAP: Chloramphenical
AOZ: Furazolidone
AMOZ: Furaltadone
AHD: Nitrofurantoin
SEM: Nitrofurazone
TPC: Total plate count
E. coli: Escherichia coli

V. cholerae: Vibrio cholerae

ND: Not Detected
Neg: Negative
Pos: Positive


Environmental and Economic Evaluation of Shrimp Culture Practices in Vietnam
Research Institute for Aquaculture No 1 & The University of West Australia
23
4.4 Costs of production
Tables 4 presents culture costs for each of the nine households on a half-hectare
basis. Results as a percentage of total costs are presented in Table 5.

Seed purchases include purchase of between 40,000 to 120,000 seed per half-
hectare at 15 days post-larvae. The cost of seed averages 35VND/seed and ranges
between 20 and 50VND/seed. The average cost of seed purchases is 2.9 million VND
per half-hectare per year, and contributes 6.2% of total costs. This is similar to the
cost of seed purchases of non-BMP farmers (3.4 million VND/half-ha) (Thanh et al.
2007). Generally, the shrimp seed is sourced from within the province, except in Ha
Tinh where farmers source their seed from Nghe An, the province to the north.

A summary of quality tests conducted on the seed are provided below:
• 7 farmers checked for PCR (Highly sensitive detection methods for some
pathogens that employ DNA amplification methods based on the polymerase
chain reaction (PCR)),
• 3 farmers checked for perceptibility,
• 3 farmers checked for “salinity shock”,
• 2 farmers checked for MBV (Monodon Baculo Virus),
• 1 farmer checked for “formal shock”, and
• No farmers checked for parasites.

Off-farm labour is generally used for pond preparation and repairs. The cost of off-
farm labour is between 30,000 and 45,000VND/person-day, depending on the task.
The average cost of off-farm labour per half-hectare farm is 5.1 million VND per year,
contributing to 11.0% of total costs, the second largest cost for the operation.




24
Table 4: Shrimp culture costs (million VND/0.5ha)
Household
number
Seed
purchase Labour Feed
Water
processing
materials Chemicals Fertilisers Energy Depreciation
Land
taxes and
rent
Total
1 0.8 3.6 12.7 1.3 0.7 0.3 1.9 1.5 0.7 23.5
2 1.4 4.2 20.7 1.0 1.4 0.5 1.4 2.1 1.4 34.2
3 1.1 5.0 15.2 1.4 1.7 0.4 1.3 1.5 1.1 28.6
4 4.8 10.0 77.1 4.2 12.6 0.2 8.0 12.0 12.0 140.9
5 4.4 6.8 52.0 1.7 6.6 0.1 4.9 2.2 1.7 80.4
6 2.0 0.0 7.4 1.0 6.7 0.1 1.7 0.5 0.5 19.9
7 4.5 9.5 9.5 3.3 4.3 1.6 0.0 8.0 1.0 41.7
8 4.5 7.0 21.9 2.4 4.1 0.2 0.0 0.0 0.0 40.1
9 4.8 0.8 47.8 4.2 9.0 0.2 8.0 8.0 1.2 84.0

Average 3.2 5.2 29.4 2.3 5.2 0.4 3.0 4.0 2.2 54.8
CV (%)
55.8 67.0 81.8 57.2 74.9 122.5 104.6 106.6 170.7 72.5


Table 5: Shrimp culture costs (% of total costs)
Household
number
Seed
purchase Labour Feed
Water
processing
materials Chemicals Fertilisers Energy Depreciation
Land
taxes and
rent
1 3.6 15.2 54.0 5.5 3.0 1.1 8.2 6.3 3.1
2 4.1 12.3 60.6 3.1 4.1 1.6 4.1 6.1 4.1
3 3.8 17.5 53.0 4.8 5.9 1.3 4.5 5.2 3.8
4 3.4 7.1 54.7 3.0 8.9 0.1 5.7 8.5 8.5
5 5.5 8.4 64.7 2.1 8.2 0.1 6.1 2.8 2.1
6 10.0 0.0 37.1 5.2 33.6 0.4 8.5 2.5 2.5
7 10.8 22.8 22.9 7.9 10.2 3.8 0.0 19.2 2.4
8 11.2 17.5 54.6 6.0 10.1 0.5 0.0 0.0 0.0
9 5.7 1.0 56.9 5.0 10.7 0.2 9.5 9.5 1.4
Average 6.5 11.3 51.0 4.7 10.5 1.0 5.2 6.7 3.1

25
The households use mostly commercial feeds (including UP, Robet, wind and KP90),
although the three households in Thua Thien-Hue also use homemade feeds. The
average price of the feed is approximately 18,000VND/kg. Total feed costs for a half-
hectare farm is 24.5 million VND/year or 52.6% of total costs – by far the largest
cost for the operation (the second largest cost is labour at 11%). This is slightly more
than the average amount of feed used by non-BMP farmers, where average total feed
costs per half-hectare are approximately 17.4 million VND/year (Thanh et al. 2007).

Water processing materials include:
• Agricultural (CaO) and industrial (CaCO
3
) lime used by all nine farmers,
• Diatomit used by one farmer, and
• Other materials, used by five farmers.
• No farmers use Zoelite.

The average cost of materials for water processing is 2.0 million VND or 4.4% of total
costs. This is similar to the average non-BMP farmer who spends approximately 1.8
million VND on water processing material (Thanh et al. 2007). Not that the non-BMP
used higher quantities of Diatomit, Dolomite and Zoeline.

A number of chemicals are used during shrimp production, including:
• Chlorine used by six farmers,
• Saponine used by three farmers,
• QM1 used by one farmer,
• BKC used by three farmers,
• BRF 2 used by five farmers,
• Super VS used by three farmers,

• Zylmetyl used by three farmers as a digestive,
• Mineral used by five farmers, and
• Other chemicals including bean flour.

The average cost of chemicals is 4.4 million VND or 9.5% of total costs.

Fertilisers are used to stimulate the growth of algae for food for the shrimp and
include:
• NPK (nitrogen, phosphorus and potassium), used by all nine farmers,
• Organic manure, used by two farmers, and
• Phosphorus used by three farmers.

The average cost of fertilisers is 0.4 million VND or 0.9% of total costs, the smallest
cost category for the farm. Energy costs are dominated by petrol costs, and account
for 2.4 million VND or 5.1% of total costs (this is slightly more than the energy costs
of non-BMP households - 1.8 million VND/half-hectare). Depreciation of culture
equipment (including pumps and paddle wheels) costs 3.2 million VND per year or
6.9% of total costs. Land taxes and rental cost 1.6 million VND per year or 3.4% of
total costs.