development of rice-shrimp farming in mekong river delta, vietnam

USAID Mekong Adaptation and Resilience

to Climate Change (USAID Mekong ARCC)

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam (ENGLISH VERSION)

JANUARY 2016

This publication was produced for review by the United States Agency for International Development. It was

prepared for USAID Mekong ARCC by AMDI.

USAID Mekong Adaptation and Resilience to

Climate Change (USAID Mekong ARCC)

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam (ENGLISH VERSION)

Program Title: USAID Mekong Adaptation and Resilience to Climate Change

(USAID Mekong ARCC)

Sponsoring USAID Office: USAID/Asia Regional Environment Office

Contract Number: AID-486-C-11-00004

Contractor: Development Alternatives Inc. (DAI)

Subcontractor: Asian Management and Development Institute (AMDI)

Consultant Team: PHẠM ANH TUẤN, Consultant (Team Leader);

TRẦN NGỌC HẢI, Can Tho University; and

TRỊNH QUANG TÚ, Aquaculture Economic and Planning Institute

Date of Publication: January 2016

This publication has been made possible by the support of the American People through the United

States Agency for International Development (USAID). The contents of this document are the sole

responsibility of DAI and AMDI and do not necessarily reflect the views of USAID or the United

States Government.

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam | Page i

ACKNOWLEDGEMENTS

We, the authors, would like to express our sincere thanks to:

Directorate of Fisheries (Vietnam Ministry of Agriculture and Rural Development) for arrangement of

our working schedules with local authorities in the Mekong Delta.

United States Agency for International Development (USAID), and the USAID Mekong Adaptation and

Resilience to Climate Change Project (USAID Mekong ARCC) for financial support; and the Asian

Management and Development Institute for administration and logistics support during our field work.

Provincial Department of Agriculture and Rural Development of Kien Giang, Ca Mau, Bac Lieu, Soc

Trang, Tra Vinh for spending time with us, for providing human resources, documentation and

information related to rice-shrimp farming and for facilitating our field trips to rice-shrimp farms.

Farmers in An Bien and An Minh districts (Kien Giang Province), Thoi Binh (Ca Mau), Hong Dan (Bac

Lieu), My Xuyen (Soc Trang), Cau Ngang (Tra Vinh) for spending their time discussing rice-shrimp

farming with us.

Representatives from Directorate of Fisheries, USAID Mekong ARCC Project, Asian Management and

Development Institute (AMDI), Research Institute for Aquaculture No.2, Cuu Long Delta Rice

Research Institute, Can Tho University, Provincial Department of Agriculture and Rural Development

of Kien Giang, Ca Mau, Bac Lieu, Soc Trang, Tra Vinh, An Giang, Dong Thap, the Australian Centre for

International Agricultural Research (ACIAR), World Wildlife Fund (WWF), Deutsche Gesellschaft für

Internationale Zusammenarbeit GmbH (GIZ) and farmers who participated in the report’s Feedback

Meeting in Can Tho City in December 2015 and commented on the findings.

Pham Anh Tuan, Research team leader

January 2016

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam | Page ii

ACRONYMS

ACIAR Australian Centre for International Agricultural Research

AMDI Asian Management and Development Institute

ATC Average total cost

AVG Average

B/C ratio Benefit/Cost ratio

cm Centimeters

DAI Development Alternatives, Inc.

DARD Vietnam Department of Agriculture and Rural Development

D-Fish Directorate of Fisheries

FCR Feed Consumption Ratio

GFS Giant freshwater shrimp

GIZ Deutsche Gesellschaft für Internationale Zusammenarbeit GmbH

ha Hectare

IPM Integrated Pest Management

IUCN International Union for Conservation of Nature

kg Kilograms

LMB Lower Mekong Basin

m Meter

MARD Vietnam Ministry of Agriculture and Rural Development

MRD Mekong River Delta

n Number

NGOs Non-government organizations

NPK Nitrogen, Phosphorus, and Potassium

pcs Pieces

PL Post larvae

PR Profit return

SOPs Standard Operation Procedures

sq.m. or m2 Square meters

STD Standard Deviation

TC Total cost

TR Total revenue

TS Tiger shrimp

USAID United States Agency for International Development

USAID Mekong ARCC USAID Mekong Adaptation and Resilience to Climate Change

VND Vietnamese Dong

WLS Whiteleg shrimp

WWF World Wildlife Fund

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam | Page iii

CONTENTS

EXECUTIVE SUMMARY.................................................................................................. 1

1. OVERVIEW ................................................................................................................ 4

1.1 Status and Role of Rice-Shrimp in Mekong River Delta ..................................... 4

1.2 Research Objectives ............................................................................................... 5

2. METHODOLOGY...................................................................................................... 7

2.1 Study Time ............................................................................................................. 7

2.2 Implementation Plan ............................................................................................. 7

2.3 Data Collection....................................................................................................... 7

2.3.1 Secondary Information ............................................................................................................... 7

2.3.2 Primary Information .................................................................................................................... 7

2.4 Data Analysis and Report Writing ....................................................................... 8

3. CURRENT RICE-SHRIMP DEVELOPMENT IN MEKONG RIVER DELTA ...... 10

3.1 Kien Giang Province ............................................................................................. 10

3.2 Ca Mau Province .................................................................................................. 12

3.3 Bac Lieu Province ................................................................................................. 14

3.4 Soc Trang Province .............................................................................................. 15

3.5 Tra Vinh Province ................................................................................................ 17

4. RICE-SHRIMP SYSTEMS IN MEKONG RIVER DELTA ...................................... 20

4.1 Semi-intensive Rice-shrimp Farming ................................................................. 20

4.1.1 Specifications .............................................................................................................................. 20

4.1.2 Economic, Social and Environmental Effectiveness ........................................................... 23

4.1.3 Advantages and Limitations ..................................................................................................... 25

4.2 Semi-intensive Two Shrimp-One Rice Farming ................................................ 25

4.2.1 Specification ................................................................................................................................ 25

4.2.2 Economic, Social and Environmental Effectiveness ........................................................... 27


4.3 Semi-intensive Farming with 1 Shrimp Crop and 1 Sedge Crop .................... 28

4.4 Improved Extensive Shrimp Farming and 1 Rice Crop .................................... 29

4.4.1 Specifications .............................................................................................................................. 29

4.4.2 Economic, Social and Environmental Efficiency .................................................................. 32

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam | Page iv


5. CHALLENGES TO THE DEVELOPMENT OF RICE-SHRIMP IN THE MEKONG

RIVER DELTA ................................................................................................................. 35

5.1 Climate Change .................................................................................................... 35

5.2 Shrimp PL and Farming Technique ................................................................... 36

5.3 Rice Varieties ........................................................................................................ 37

5.4 Infrastructure........................................................................................................ 38

5.5 Current Policy ...................................................................................................... 39

5.6 Production Management ..................................................................................... 40

5.7 Production Organization ..................................................................................... 41

5.8 Market ................................................................................................................... 41

6. SOLUTIONS FOR SUSTAINABLE RICE-SHRIMP FARMING IN MRD ........... 43

6.1 Rice-shrimp Adaptation to Climate Change ..................................................... 43

6.2 Policy Solutions .................................................................................................... 43

6.3 Management Solutions ........................................................................................ 44

6.4 Infrastructure Solutions ....................................................................................... 45

6.5 Model Replication / Aquaculture Extension Solutions ..................................... 45

6.6 Production Solutions ........................................................................................... 46

6.7 Market and Trademark Development Solutions .............................................. 46

6.8 Research Solutions ............................................................................................... 47

6.8.1 Current Research ...................................................................................................................... 47

6.8.2 Priority Research ....................................................................................................................... 47

7. Recommendations and suggestions ....................................................................... 50

7.1 The Ministry of Agriculture and Rural Development, Vietnam ...................... 50

7.2 The USAID Mekong ARCC Project ................................................................... 50

REFERENCES .................................................................................................................. 52

APPENDIX .............................................................................. Error! Bookmark not defined.

Development of Rice-Shrimp Farming in Mekong River Delta, Vietnam | Page 1

EXECUTIVE SUMMARY

The Mekong River Delta (MRD) is the key brackish water shrimp farming region of Vietnam. It features

diverse farming systems including intensive, semi-intensive, improved extensive, shrimp rotation and

intercropping including shrimp-fish, shrimp-mangrove and rice-shrimp. Rice-shrimp farming is common

in coastal provinces, and is considered by the Vietnam Ministry of Agriculture and Rural Development

(MARD) a potential model for expansion and improvement. This report contains a current situation

assessment, identifies constraints and challenges, and proposes appropriate solutions for improving the

efficiency and sustainable development of rice-shrimp farming in the MRD.

Key findings of the study are:

Rice-shrimp farming in MRD started in the early 1970s, particularly after Decree 09/2000/ND-

CP allowed the conversion of low productivity land (previously under rice farming, salt

production, and coastal wetlands) to aquaculture.

Rice-shrimp farming has expanded rapidly. In 2000 the total area in Vietnamwas 71,000 ha, and

in 2014 it reached 152,977 ha, accounting for 27.98 percent of the total area of brackish water

shrimp farming. The provinces with large areas of rice-shrimp are Kien Giang (71,500 ha), Ca

Mau (43,297ha), Bac Lieu (28,285ha), Soc Trang (7,581 ha), Ben Tre (4,833 ha).

MARD plans to develop the rice-shrimp area in MRD to reach 200,000 ha producing 100,000

ton of shrimp by 2020, and 250,000 ha producing 125,000-150,000 ton by 2030. The value

could reach 25,000–30,000 billion VND by 2030, providing stable jobs for over 1 million people

in rural areas.

Production of farmed shrimp from the rice-shrimp system was estimated at 65,000 tons in

2014, accounting for 15 percent of total brackish water shrimp production in MRD and 11

percent of national shrimp production. Every year, 1 hectare of rice-shrimp farming area

produces 300-500 kg shrimp and 4-7 ton of rice.

Tiger shrimp (Penaeus monodon) and whiteleg shrimp (Litopenaeus vannamei) are the major

species, while gender-mixed and all-male giant freshwater shrimp (Macrobrachium rosenbergii)

and sea crab are also intercropped in the rice-shrimp system. The common rice varieties in

rice-shrimp are ST, Mot Bui Do, Nang Keo, OM5451, OM2017, OM6377 and OM6677. These

have high productivity but only in fields with salinity level lower than 5 percent.

The major limitations to the efficiency of rice-shrimp systems in MRD are insufficient high quality post

larvae (PL) for tiger and whiteleg shrimp, limited capacity in management of PL quality, and lack of giant

freshwater shrimp PL. Water supply and drainage infrastructure in many areas of rice-shrimp are below

standard for sufficiently supplying water for rice and shrimp farming.

The rice-shrimp models in MRD include: semi-intensive model with one tiger shrimp/whiteleg shrimp

crop and one rice crop, semi-intensive with two white leg shrimp crops and one rice crop, and

improved extensive model of rice-shrimp. The semi-intensive farming model with 1-2 shrimp crops and

1 rice crop is common in Soc Trang and Tra Vinh, while in the province of Kien Giang, Ca Mau and

Bac Lieu, the improved extensive rice-shrimp model forms a large proportion of the rice growing area.


The semi-intensive rice-shrimp model brings higher returns than the improved extensive model, but

limitations include large investment requirements, high risk of disease, low quality water due to farming

infrastructure, unguaranteed PL quality and limited capital of farmers. The improved extensive model

requires lower investment but offers high efficiency, increased environmental sustainability; however

the maximum profit gained is lower than from the semi-intensive model.

Climate change impacts including sea level rise, saline water intrusion, high soil and water salinity levels,

prolonged dry season, heatwaves, short rainy season, drought, as well as human management activities

like the construction of hydroelectric dams in the upper Mekong River are affecting the sustainable

development of rice-shrimp systems in MRD. In many regions of Ca Mau, Kien Giang and Bac Lieu

provinces, due to high and prolonged salinity and freshwater shortages, farmers have changed from

one shrimp crop-one rice crop to one shrimp crop-one sedge grass, or two shrimp monoculture crops

without rice. In addition, due to the high profit from shrimp farming, many farmers in Ca Mau and Kien

Giang have spontaneously converted rice monoculture areas to rice-shrimp.

Although rice-shrimp models are considered by MARD effective and sustainable farming systems,

farmers are not provided with sufficient technical guidelines and materials, and optimal technical

specifications and guidelines have not been identified to maximize efficiency in each farming model.

Shrimp farmed in rice-shrimp areas offer a high level of food safety and a sustainable product. They are

preferred by processing plants and consumers in terms of quality but farmers have not yet received

added value from this product quality, and commercial shrimp raised in rice-shrimp systems have no

trademark or brand.

The Vietnam Government has policies to support farmers affected by natural disasters and epidemics,

policies on management and protection of rice paddy land, policies to encourage cooperation

development, linking production with consumption of agricultural products, and building large research

trial fields. However some of the existing policies are not consistent with the conditions of production,

the economy and society in rice-shrimp areas in MRD, thus do not achieve the objectives of the policy.

To promote more efficient and sustainable rice-shrimp, particularly in the context of climate change

which is having and will continue to have significant impacts on the MRD region, this report proposes

the following recommendations:

Reviewing and adjusting MARD’s rice-shrimp MRD development plan to 2020 with vision to

2030, on the basis of reviewing the effectiveness of shrimp farming, rice cultivation and the

impacts of climate change on farming systems.

Capacity building on production and quality management of PL of tiger shrimp, whiteleg shrimp

and giant freshwater shrimp. Selecting and developing rice varieties with a higher salt tolerance

than 5 percent, with short growing time.

Providing training, education and technical guidelines on the PL nursery model for farmers to

replicate, and promote the efficiency of the PL nursery.

Adjusting and supplementing the policies related to supporting farmers in the rice-shrimp area

affected by natural disasters and epidemics, policies on management and protection of paddy

land, policies to encourage development of farmer cooperatives, linking production with

consumption of agricultural products, and establishing large research trial fields.


Increasing investment in water supply infrastructure and environmental monitoring systems to

ensure water quality management is consistent with rice and shrimp farming.

Focus on research and market development, particularly the consumer market for giant

freshwater shrimp, tilapia and other aquaculture species with potential development in climate

change impacted rice-shrimp regions. Develop a trademark for high quality commercial shrimp

from the MRD rice-shrimp region.

Suggested priority research studies are: Identifying maximum and optimal productivity of

sustainable shrimp farming in rice-shrimp models; improving giant freshwater shrimp PL

production technology to ensure sufficient supply for farming; selecting and creating rice

varieties with high salt tolerance; developing new sustainable aquaculture models adaptive to

climate change in the rice-shrimp area; and building production models which link suppliers of

rice seed, shrimp PL, feed and material inputs with farmers, processors, and consumers of

shrimp and rice.


1. OVERVIEW

1.1 Status and Role of Rice-Shrimp in Mekong River Delta

Brackish water shrimp farming is one of the mainstays of Vietnam’s aquaculture in general and the

Mekong River Delta in particular. In 2014, the total brackish water shrimp farming area was about

658,000 ha nationwide, shrimp production reached 560,000 tons, and shrimp export value reached

nearly US$4 billion. Of this, 546,735 ha of shrimp are located in MRD, producing 420,000 tons of

shrimp, accounting for nearly 83.1 percent of the total area and 75 percent brackish water shrimp

production nationwide (MARD, 2014).

The shrimp farming models in MRD vary in production intensity: intensive farming, semi-intensive,

extensive, improved extensive, and vary in farming systems: soil ponds, indoor canvas covered ponds,

mangrove and rice fields. According to the Vietnam Institute of Fisheries Economics and Planning (2015)

intensive shrimp farming accounts for 5.6 percent of the MRD area, semi-intensive farming and

improved extensive farming account for 35.9 percent, ecological extensive farming accounts for 30.5

percent, and rice-shrimp farming 28 percent.

Rice-shrimp farming in MRD has occurred for the past 50 years. Original rice-shrimp systems were

formed from the 1970s, when farmers stocked natural PL into their rice fields from the tidal water in

the dry season when the rice production was ineffective in MRD coastal areas. Natural PL was mainly

species of Penaeus shrimp i.e. P. monodon and P. merguiensis. Tiger shrimp (Penaeus monodon) farming

started from the early 1990s as a result of successful PL production in artificial hatchery conditions.

The initiative in shrimp PL and the expanding shrimp export and consumption market have promoted

aquaculture in general and rice-shrimp farming in particular in MRD.

Rice-shrimp farming has experienced rapid growth rates in MRD. In 2000 the rice-shrimp area was

71,000 ha, and in 2014 the total rice-shrimp farming area reached 152,977 ha in MRD, accounting for

27.98 percent of the brackish water shrimp farming area in the region. Production of farmed shrimp

from the rice-shrimp system was estimated at 65,000 tons in 2014, accounting for 15 percent of total

brackish water shrimp production in MRD and 11 percent of national shrimp production. The provinces

with large area of rice-shrimp farming area Kien Giang (71,500 ha), Ca Mau (43,297ha), Bac Lieu

(28,285ha), Soc Trang (7,581 ha). Every year, 1 ha of rice-shrimp area produces on average 300-500 kg

of shrimp and 4-7 tons of rice. The Vietnam Government considers rice-shrimp farming an efficient,

sustainable farming system with low investment needs (D-Fish, 2015). Shrimp farmed in rice fields

mainly uses natural foods, low feed costs, less disease, the market shrimp has good quality (due to low

use of chemicals and antibiotics), the ecological environment is protected because growing rice uses

waste products from shrimp farming, and the farming model is adapted to ecological conditions in

coastal areas affected by saline intrusion, where it is not viable to grow rice all year round.


Figure 1. Rice-shrimp area of Vietnam’s Mekong River Delta coastal provinces

Considering the rice-shrimp system not only an efficient method in term of economics, but also

sustainable farming practices, which is significant in many aspects in MRD, MARD is planning a policy

to develop and further improve the efficiency of rice-shrimp farming. According to the development

plan for aquaculture in the period 2016-2020, with vision to 2030, the rice-shrimp farming area in MRD

will reach 200,000 ha in 2020 to produce 100,000 tons of shrimp, and in 2030 reaching 250,000 has

and produce 125,000-150,000 tons of shrimp, and the value will reach 25,000-30,000 billion VND,

creating stable jobs for over 1 million workers (MARD, 2015: No.7907/TB-BNN-VP). However the

development of rice-shrimp system in MRD is also confronted with the challenges, especially the

impacts of climate change. The trend of sea level rise, saline intrusion, longer and more severe dry

seasons, shorter rainy seasons with less rainfall, plus the construction of hydroelectric dams on the

upstream of the Mekong River system are affecting sustainable development of agriculture, forestry

and fisheries activities in general, and rice-shrimp systems in particular in MRD.

1.2 Research Objectives

To effectively implement their rice-shrimp development plan in MRD, MARD assigned D-Fish to

urgently develop and submit to the Ministry the plan for “Sustainable Development of Rice-

shrimp farming systems in Mekong River Delta in the period 2016-2020, with vision to

2030.” Therefore it is essential to conduct a comprehensive review on the current situation,

development potentials, advantages, limitations in technical, economic, market, social, environmental

aspects, and the challenges for the existing rice-shrimp farming in MRD, which will provide a basis to

propose solutions for sustainable development of the rice-shrimp model.

USAID Mekong Adaptation and Resilience to Mekong Climate Change Project (USAID Mekong ARCC),

the Asian Management and Development Institute (AMDI) and D-Fish have supported the expert team

to conduct a comprehensive review on the rice-shrimp farming development in MRD.

The objectives of the study are to:

Tien Giang

0.32%

Ben Tre

3.06%

Tra Vinh

1.15%

Soc Trang

4.80%

Bac Lieu

17.92%

Ca Mau

27.44%

Kien Giang

45.31%


Identify the current situation of the area, yield, planning, infrastructure, organization of production,

market, current policies related to rice-shrimp; assess rice-shrimp farming models in terms of technical,

economic and social aspects, impacts of climate change on the model; and propose solutions for

sustainable development of rice-shrimp system in MRD.

The study findings and results will provide important information for the development of the scheme

on sustainable development of rice-shrimp farming system in MRD period 2016-2020, with vision to

2030.


2. METHODOLOGY

2.1 Study Time

The study was conducted from 12th October to 30th December 2015.

2.2 Implementation Plan

October 12 to October 24 2015: Prepare a questionnaire to collect information, including

questionnaires for the provincial authorities, and the questionnaire for rice-shrimp farming farmers.

Gather documents relevant to rice-shrimp development in MRD.

October 25 to November 4: Conduct field surveys and collect information at the rice-shrimp

farming provinces. The survey was conducted in 5 provinces: Kien Giang, Ca Mau, Bac Lieu, Soc Trang

and Tra Vinh.

November 5 to December 15: Analysis of data and writing draft report.

December 10: The draft report was presented in the Workshop on Study Findings in Can Tho.

December 11-30: Collect and review comments from the Workshop to adjust, supplement and

complete the report

December 30: Submit final report.

2.3 Data Collection

Information on rice-shrimp development in MRD was collected from two sources:

2.3.1 Secondary Information

Planning reports, projects and policies related to fisheries and rice-shrimp development of the

Government, MARD and MRD coastal provinces. The final reports, data and research results related

to rice-shrimp development, market and climate change in MRD (scientific topics, fisheries extension

projects, other projects and thesis) are from D-Fish, Directorate of Water Resources, Agricultural

Extension Center, research institutes, universities and NGOs.

2.3.2 Primary Information

Field surveys and interviews in 5 provinces with large rice-shrimp farming area in MRD: Kien Giang, Ca

Mau, Bac Lieu, Soc Trang and Tra Vinh.


Discussion on rice-shrimp model in Tra Vinh

Discussion on rice-shrimp model in Kien Giang

Interviewing rice-shrimp farmer, Thoi Binh, Ca Mau

Interviewing rice-shrimp farmer, Hong Dan, Bac Lieu

Figure 2. Consultant team discussed and interviewed provincial management agencies and

farmers in rice-shrimp area of MRD

In each province interviews were conducted with management officials related to rice-shrimp

development including: Aquaculture Departments, Agricultural Extension Center, Department of

Irrigation and Department of Crop Production. For detailed interview and discussion contents see

Appendix 1 (Appendix in Vietnamese version only).

In each province the consultant team visited and interviewed rice-shrimp farmers practicing different

models. Detailed questionnaires, detailed list of managers, and the rice-shrimp farmers interviewed are

in Vietnamese version only.

2.4 Data Analysis and Report Writing

The data and information collected were aggregated and analyzed to evaluate technical, economic,

social and environmental aspects, to assess the current situation of infrastructure, the existing policies

and to propose policies for effective development of rice-shrimp.


The findings and recommendations of the expert team were presented at the Workshop on Study

Findings with the participation of representative of USAID Mekong ARCC Project, leaders of the AMDI,

and representatives of aquaculture management agencies: D-Fish, Department of Agriculture and Rural

Development of Kien Giang, Ca Mau, Bac Lieu, Soc Trang, Tra Vinh, Ben Tre, Dong Thap, An Giang;

Institutes and Universities: Research Institute for Aquaculture II, Cuu Long Delta Rice Research

Institute, Can Tho University. International organizations: ACIAR, WWF Vietnam, GIZ, IUCN and local

rice-shrimp farmers.

The comments at the workshop were reviewed and synthesized in the process of finalizing the report.


3. CURRENT RICE-SHRIMP

DEVELOPMENT IN MEKONG RIVER

DELTA

3.1 Kien Giang Province

Kien Giang has 6348.53 km2 total land area and a population of 1.736 million people. The terrain

consists of low hills, plains and sea with 137 islands and islets; 200 km long coastline, more than 100

estuaries and canals draining into the sea, with extensive intertidal areas creating favorable conditions

for aquaculture development for various types of salty, brackish and fresh water farming. Aquaculture

species are various such as tiger shrimp, whiteleg shrimp (Litopenaeus vannamei), crab, fish in cages

(grouper, cobia) and mollusks. In particular, the model of shrimp farming in rotation with rice has been

strongly developed, bringing high economic efficiency and contributing to improving the life of people

in rural coastal regions.

Figure 3. Brackish water intensive and semi-intensive shrimp farming (purple) and improved

extensive rice-shrimp farming (orange) in Kien Giang Province, 2014


Kien Giang started shrimp farming in rice paddy fields in 2002, and now has the largest rice-shrimp

farming area among MRD provinces. In 2014 the rice-shrimp area reached 71,500 ha, accounting for

80.7 percent of the brackish water shrimp farming area of the province (88,648 ha), and 45.3 percent

of the MRD’s rice-shrimp area. To October 2015, the rice-shrimp area reached 77,264 ha out of total

98,987 ha brackish water shrimp farming, accounting for 78.1 percent, an increase 9.2 percent higher

than planned.

Rice-shrimp farming is concentrated in the districts of An Bien, An Minh, U Minh Thuong, Vinh Thuan,

Go Quao, and the Long Xuyen quadrangle including Hon Dat and Kien Luong. In the period 2010-2015,

the rice-shrimp farming area in Kien Giang had an average growth of 7.1 percent each year. Shrimp

yield in 2010 had an average of 300 kg/ha; in 2014 it reached 373 kg/ha, an increase of 6.1 percent per

year. To October 2015 rice-shrimp farming area exceeds the plan’s target by 9.1 percent. The shrimp

production is 26,699 tons, equal to 95 percent of the plan. The average shrimp yield is lower than in

2014 due to prolonged hot weather, and some areas experienced significant fatalities of shrimp.

Table 1. Rice-shrimp development in Kien Giang Province 2010-2015

No. Rice-shrimp 2010 2011 2012 2013 2014 2015

1 Area (ha) 64.673 66.403 68.291 69.586 69.665 77.264

2 Production (Ton) 19.382 21.142 21.385 23.030 26.305 26.699

3 Productivity (Ton/ha) 0.3 0.318 0.313 0.331 0.373 0.346

Source: Kien Giang DARD (2015)

Tiger shrimp is a common aquaculture species. This shrimp crop is grown January to August. After

harvesting, farmers wash out salt from field to prepare for rice cultivation. This practice usually relies

on rainfall. Common rice varieties are OM2517 and ST5, with productivity of 4-5 ton/ha, with some

regions reaching 6-7 ton/ha.

From 2012 whiteleg shrimp began to be farmed in rice fields and giant freshwater shrimp

(Macrobrachium rosenbergii) from 2014. Giant freshwater shrimp are stocked concurrently with tiger

shrimp, and are common in districts of Vinh Thuan and U Minh Thuong. In 2015, there was 3,578 ha

of giant freshwater shrimp production, with production of 2,420 tons, and average yield of 676 kg/ha.

Sea crabs are also farmed in rice fields in An Minh District with tiger shrimp and whiteleg shrimp for

the shrimp crop, and are also stocked in the rice crop with stocking densities of 1PL/8-10 sq.m.

PL of tiger shrimp, whiteleg shrimp, giant freshwater shrimp and sea crabs are largely bought from

hatcheries outside the Kien Giang Province. PL produced in Kien Giang only meets 20 percent of local

demand. PL shrimp are mostly bought through dealers without clear origin and quarantine; farmers still

have a common practice of supplementing PL if losses occur. Most people directly stock PL shrimp into

ponds without a PL nursery and continuously stock PL (2-3 times in one crop), and do not completely

harvest shrimp before they re-stock with new PL.

According to the province's plan, in 2020 the rice-shrimp area of Kien Giang will reach 80,000 ha,

production will reach 0.4-0.5 tons/ha, and in 2030 rice-shrimp area will reach 90,000 ha. The expansion

areas for rice-shrimp are An Bien, U Minh Thuong, Hon Dat and Kien Luong where currently there


are two rice crops. Low effectiveness due to salinity intrusion means switching to one rice crop-one

shrimp crop is a suitable adaptation.

Infrastructure for rice-shrimp farming in Kien Giang Province remains below standard, that is: it has an

inactive salt control and fresh water supply system in many farming areas. According to the planning

on upgrading the sea dike in An Minh-An Bien, 27 water regulation culverts will be built. However

there are only 6 culverts (Thu Bay channel, Xeo Doi, Xeo Quao, Xeo Nhau, Thuong Luong, Ro Ghe),

thus increasing salinization and affecting the area and yield of the rice-shrimp farming region. Many rice-

shrimp fields have low embankments, poor water retention and no settling ponds, which also

significantly affect the efficiency of shrimp farming.

3.2 Ca Mau Province

Ca Mau has been identified as major center for fisheries, especially brackish water shrimp farming. In

2014, brackish water shrimp farming area was 262,915 ha including intensive shrimp farming, improved-

extensive farming, rice-shrimp, shrimp-mangrove and combination of fish and crab. This produced

150,000 tons of shrimp, with export turnover exceeding US$1.3 billion. The value of the fisheries

industry accounted for 30 percent of provincial GDP; creating over 140,000 jobs.


extensive rice-shrimp farming (orange) in Ca Mau Province, 2014


Ca Mau began rice-shrimp farming in 2000. In 2014 the rice-shrimp farming area was 43,213 ha and it

reached 51,570 ha in October of 2015, accounting for 17.9 percent of the brackish water shrimp

farming area of Vietnam (262,915 ha), and ranked as the second largest rice-shrimp farming area in

MRD. Rice-shrimp farming is concentrated in the districts of Thoi Binh (34,713 ha), U Minh (9,857 ha),

Tran Van Thoi (4,000 ha), Cai Nuoc (2,000 ha) and the city of Ca Mau (1,000 ha).

In the first years of rice-shrimp farming, limited experience and inadequately invested infrastructure

(farming pond, water supply system) led to low productivity of 100-200 kg/ha. In the period 2005-2014

the rice-shrimp farming area increased quickly and the productivity was enhanced to 320-350 kg/ha,

and rice productivity reached 4.0-4.2 tons/ha.

Shrimp farmed in rice fields includes tiger shrimp, whiteleg shrimp and giant freshwater shrimp. Rice-

shrimp farming is diverse, including: one shrimp crop – one rice crop, one shrimp crop – one rice crop

intercropped with shrimp. Tiger shrimp is the most common. Giant freshwater shrimp and sea crab

are usually stocked concurrently.

In 2014, Ca Mau produced 22 billion PL12-14 tiger shrimp and whiteleg shrimp, meeting 60 percent of

the provincial demand for shrimp PL. The number of crab PL produced locally (400 million crab PL in

2014) was sufficient to meet the demand of the province and provide additional supply to Mekong

Delta provinces. Giant freshwater shrimp PL was totally imported from outside, mainly Dong Thap

Province, An Giang Province, Can Tho Province, Thailand and China.

Although DARD has quarantine facilities for shrimp, farmers mostly buy PL shrimp through dealers of

unknown origin, with no quarantine, and continuous PL stocking is quite common. Most people directly

stock shrimp PL into ponds without a nursery and continuously stock PL (2-3 times in one crop), and

do not completely harvest before stocking new PL.

Infrastructure for rice-shrimp remains limited; many drainage canals are clogged with sediment, not

ensuring water supply and drainage. The fresh water supply source for many farming areas is insufficient

and unstable due to dependence on rainfall.

There is no difficulty in selling commercial shrimp farmed from the rice-shrimp model. However there

are limitations including:

Independent harvest by households;

Scattered harvesting time and locations;

Increased cost for collecting shrimp; and

Reduced shrimp price at locality.

According to the Government plan (Decision 1116/QD-UBND dated 19/11/2001), in 2010 Ca Mau

had 90,000 ha under rice-shrimp, however, some regions (Cai Nuoc, southern Ca Mau) are currently

experiencing severe saline intrusion and are inappropriate for rice farming, therefore switched to

shrimp specialized farming area (extensive, improved-extensive and intensive), the province adjusted

the plan (Decision 1586/UBND dated 13/10/2011) to reduce the rice-shrimp area to 45,000 ha. As the

rice-shrimp model has high efficiency, some farmers (in Thoi Binh, U Minh and Ca Mau city) in the area

with suitable rice-shrimp farming areas spontaneously transferred from two rice crops to rice-shrimp.

The total spontaneously transferred area was 6,730.5 ha, including 3,586.9 ha of intensive rice area and


3,143.6 ha of other land (sugarcane, indigo, one rice crop). The province has set up an inter-sector

working group (Group 249, Decision No. 249/QD-UBND dated 15/02/2015) to review, examine and

evaluate the spontaneous transfer to propose adjustment of rice-shrimp planning in Ca Mau. Group

249 submitted a draft proposal to the Ca Mau Provincial People's Committee to approve 51,570 ha of

rice-shrimp farming and for 4,944 ha of rice-shrimp to be transferred to specialized shrimp farming.

3.3 Bac Lieu Province

Rice-shrimp farming began in Bac Lieu Province in 2001. The rice-shrimp farming area increased rapidly,

in 2001 it was 5,851 ha, and by 2014 was 28,285 ha, accounting for 23.6 percent of the total brackish

water shrimp farming area of the province (119,996 ha).

Figure 5. Brackish water intensive and semi-intensive shrimp farming (purple), improved

extensive rice-shrimp farming (orange), and rice-shrimp farming (yellow) in Bac Lieu Province,

2014

By the end of 2015, 30,500 ha of rice-shrimp farming is planned, 40,000 ha planned by 2020 and 43,000

ha by 2030. Rice-shrimp farming is concentrated around the northern Highway 1A, including districts

of Phuoc Long (9,500 ha), Hong Dan (20,100 has) and part of Gia Rai (500 ha), Vinh Loi (400 ha).


At October 2015 the total shrimp farming area was 29,867 ha, of which Hong Dan made up 20,117 ha,

Phuoc Long 9,000 ha, Gia Rai 350 ha, Vinh Loi 400 ha. Rice-shrimp farming area of the province is

13,353 ha, including 8,200 ha in Hong Dan district (40.7 percent), 5,010 ha in Phuoc Long district (52.7

percent), 23 ha in Gia Rai (4, 6 percent), and 120 ha in Vinh Loi district (30 percent). The reasons for

the small area of rice farming after the shrimp crop are the short rainy season (late start, early end),

less rainfall (20-30 percent lower than the average of many years), small floods, low water level of the

rivers, lack of freshwater to remove salt from field. Most of the area that is unable to cultivate rice is

continued in shrimp or crab farming.

Every year, the shrimp crop begins from February or March and ends in July, from August to September

farmers start sowing seed (with long growth period rice varieties) or from September to October

(with short growth period rice varieties).

For the shrimp crop: tiger shrimp, whiteleg shrimp, the stocking densities are 2-3 PLs/m2, an average

yield of 300-400 kg/ha, average profit of 35-50 million/ha.

Common rice varieties for the rice crop: Mot Bui Do, OM5451, OM2017, HS182, average yield of 4.5

to 6 tons/ha.

In addition to tiger shrimp and whiteleg shrimp, giant freshwater shrimp and crab are also farmed in

the rice-shrimp system. Giant freshwater shrimp is often stocked in rice crop when saline level in paddy

fields is low, with a stocking density of 0.5-1PL/m2, averaged yield of 90-100g/ha, and average profit of

10-15 million VND/ha.

Tiger shrimp, whiteleg shrimp and crab PL are produced in local hatcheries, and provide sufficient

supply for provincial demand and enough to supply other provinces in the MRD. Giant freshwater

shrimp PL mainly come from outside the province; particularly male giant freshwater shrimp that are

produced in the shrimp hatchery of Minh Hai Fishery Research Sub-Institute (Research Institute for

Aquaculture II) in Bac Lieu.

Farmers mostly buy shrimp PL through dealers of unknown origin, with no quarantine, and the situation

of continuous PL stocking in ponds is common. Most people directly stock PL shrimp into ponds

without a nursery and continuously stock PL (2-3 times in one crop), and do not completely harvest

before they start stocking new PL.

3.4 Soc Trang Province

Rice-shrimp farming started in Soc Trang Province in 1992. The first form of rice-shrimp farming was

stocking tiger shrimp in rice paddy fields with surrounding ditches, which were 1-1.2 m deep, accounting

for 10-20 percent of the field area. Due to huge profits earned from shrimp farming, most shrimp

farming ponds in Soc Trang have now been lowered 30-50 cm, and the edges are embanked higher,

creating ponds with water surface depth of 0.6-0.8 m and the depth of surrounding ditches of 1.5-1.8

m. Many rice paddy fields in Soc Trang are completely lowered without surrounding ditches like the

common rice-shrimp ponds.

The rice-shrimp farming area in Soc Trang has increased rapidly, 7,929 ha in 2010, 9,919 ha in 2014,

accounting for 50.2 percent of brackish water shrimp farming area in the province. By October 2015


the area was 10,271 ha. Rice-shrimp farming in My Xuyen and Vinh Chau, mostly concentrated in My

Xuyen District, has 10,000 ha, accounting for 97.3 percent of the province's rice-shrimp area.

Rice-shrimp farming models include: rice-shrimp, two shrimp crops (tiger shrimp - whiteleg shrimp or

two whiteleg shrimp crops) and one rice crop. Semi-intensive rice-shrimp farming is quite common in

Soc Trang because households’ farming area in the province is smaller than other provinces.

Shrimp farming is from February to August, rice farming is from September to December. In the shrimp

crop, tiger shrimp and whiteleg shrimp are farmed. Whiteleg shrimp started to be farmed in 2013, and

the farming area is increasing in some regions such as in Hoa Tu, where whiteleg shrimp farming area

accounted for 40 percent in 2013, 50 percent in 2014 and 70 percent in 2015. Tiger shrimp stocking

density is 3-10PL/m2, and whiteleg shrimp 20-50PL/m2. Giant freshwater shrimp is stocked in rice crop,

at a stocking density of 5-10PL/100m2.


extensive rice-shrimp farming (orange) in Soc Trang, 2014


Rice varieties grown are ST5, OM7347 and Nang Keo with average yield of 5-6 ton/ha. The average

shrimp yield is 550 kg/crop/ha, and some households have a yield of 3 ton/crop/ha (in this case shrimp

are farmed in pond with lowered foundation, embanked edges, water depth of 1-1.5m, using whiteleg

shrimp, stocking density of 30PL/m2, aeration, industrial feed).

Soc Trang is located close to the Hau river system, which means it is easy to obtain fresh water to

wash out salt from fields after the shrimp crop for the rice crop, contributing to the sustainability of

the rice-shrimp model.

Soc Trang has two PL hatcheries, producing 10 million PL15 each year, mainly tiger shrimp and whiteleg

shrimp. Giant freshwater shrimp PL are imported from other provinces such as Bac Lieu, An Giang,

Dong Thap and other South Central provinces (Ninh Thuan, Binh Thuan). It is common for farmers

buy shrimp PL of unknown origin, with no quarantine. Many households have practiced a shrimp

nursery model for 5-10 days before releasing shrimp into the main pond.

Most of the rice-shrimp farmers in the Mekong River Delta operate separately. However, in Soc Trang

there have been rice-shrimp cooperatives such as the cooperative No.2 of Hoa Truc Village, agricultural

and fishery cooperative Hoa De, cooperative 14-10. The current cooperatives have 20-35 members,

and operating under the following principles:

Members share successful experiences and failures in the production of rice, shrimp, and

discuss production planning. Farmers volunteer their time for these exchanges.

Support each other in terms of capital and technology.

Agree on the general provisions on the management of rice-shrimp farming.

Most of the people interviewed were aware of the important role of maintaining one rice crop in

protecting the environment, contributing to effective shrimp farming.

The province determined the rice-shrimp farming model to be a sustainable model. The government

encourages farmers to maintain and develop the rice-shrimp model, supports the rice crop when

damaged, and does not encourage conversion into two shrimp crops, leaving out rice. For provincial

Government officials and Party members, spontaneous conversion to specialized shrimp farming and

giving up rice is a violation of regulations.

To develop rice-shrimp efficiently and sustainably, the province developed a rice-shrimp development

project period 2016-2020 and is working on branding rice and shrimp of a high quality.

3.5 Tra Vinh Province

Rice-shrimp farming in Tra Vinh Province started in 1999, concentrated in the communes of Long Hoa,

Hoa Minh, Hung My and Phuoc Hao of Chau Thanh district. In 2011 the rice-shrimp area was 4,238 ha,

in 2014 was 1,814 ha, accounting for 9.3 percent of the brackish water shrimp of the province (19,413

ha). The average rice-shrimp farming area per household in Tra Vinh is relatively small; averaging 4000-

5000 m2/household, in Hoa Minh the largest farming area of a household is 2 ha, while the smallest

farming area is 2,000 m2.



extensive rice-shrimp farming (orange) in Tra Vinh Province, 2014

Every year, the shrimp crop lasts from February to August, and the shrimp crop is followed by the rice

crop. Farmed shrimp are tiger shrimp and whiteleg shrimp, in addition some households stock crab

and giant freshwater shrimp in rice crops due to low salinity levels. Tiger shrimp stocking densityis 5-

10PL/m2, whiteleg shrimp 9-15PL/m2, crab 0.5-1PL/m2

Rice grown in Tra Vinh is made up of salt-tolerant varieties: Mot Bui Do, OM5451, OM2017, HS182,

with average yield of 4.5-6 tons/ha.

Shrimp, crab, and giant freshwater shrimp PL are majorly sourced from outside the province. Due to

a large area and scattered location, it is common for farmers to buy shrimp PL from an unknown origin

without quarantine. PL is directly stocked into the pond, and very few households apply the nursery

technique before stocking. The idea of losing farming area, in addition to some previous failures using

the nursery model (slow growth, loss, death during nursery), hinders the development and uptake of

the shrimp nursery practice.


Table 2. Rice-shrimp farming in Tra Vinh, 2011-2015

Rice-shrimp 2011 2012 2013 2014 2015

Area (ha) 4,238 3,373 3,577 1,814 2,619

Production (Ton) 1,078 623 894 526 480

Productivity (Ton/ha) 0.25 0.18 0.25 0.3 0.18

Source: Tra Vinh DARD (2015)

In 2015, 300 ha of shrimp farming (about 12 percent of the rice-shrimp area, with 21.6 million PL

stocked), concentrating in the communes of Hoa Minh and Long Hoa (Chau Thanh), suffered from

damage. Inappropriate field design (low edge, water leakage, shallow water in pond: 30-50 cm),

prolonged heat and no PL quarantine caused dead shrimp, reducing the productivity of the shrimp.

Area and rice-shrimp production in 2011-2015 gradually decreased, area dropped 4.8 percent per year

and production fell by 12.1 percent per year. The rice-shrimp area decreased due to two main reasons,

which are: farmers find shrimp farming more effective than rice and have spontaneously switched to

two shrimp crops; and some areas experienced high saline intrusion leading to ineffective rice farming

and converting to farming whiteleg shrimp. However, according to reports, in Tra Vinh there, no land

area too salty to grow rice and must be given up for shrimp.

Drivers of low shrimp productivity in Tra Vinh are unsuitable farming fields/ponds because of: low

embankments, water leakage, shallow and narrow ditches around fields; and farmers, even though they

may have received training, do not apply this training well in practice.

The locations and households that switched to two shrimp crops often feature a lower field surface,

built-up surrounding banks, and stock whiteleg shrimp with density of 60-80 PL/m2, and feed industrial

foods. There are some cases where rice-shrimp farming fields are alternated with specialized shrimp

farming in villages of Hoa Minh.

In Tra Vinh there are intensive and semi-intensive shrimp farming areas mixed with rice-shrimp areas.

The management of diseases and water sources is not satisfactory. Lack of communication and

cooperation of farmers and the authorities led to higher risk of shrimp disease outbreaks and saline

intrusion from the shrimp ponds into the rice fields.

Considering the rice-shrimp farming model to be efficient and sustainable, Tra Vinh plans to expand its

rice-shrimp area, transferring the areas currently practicing two shrimp crops in Cau Ngang, Tra Cu

to one shrimp and one rice farming. By 2020 the planned rice-shrimp farming area is 3,700 ha, and by

2030 it is 3,800 ha.

Rice-shrimp farming still operates at the individual household scale; there have been no collaborative

or cooperative models. In Tra Vinh the grouped field cooperative model is being implemented in the

intensive rice areas, however this model has not been implemented in rice-shrimp areas. In Tra Vinh

the support policy for grouped fields such as infrastructure, 50 percent seed in the first year and 30

percent in the second year is currently only applied to grouped fields. Individual business practices,

unclear benefits from cooperative and collaborative groups, negative impressions about the old-style

cooperative model and lack of decisiveness of the local authorities and managers are the major

constraints on the development of rice-shrimp production in Tra Vinh.


4. RICE-SHRIMP SYSTEMS IN

MEKONG RIVER DELTA

4.1 Semi-intensive Rice-shrimp Farming

4.1.1 Specifications

Semi-intensive shrimp farming developed in 2010 in the MRD from improved extensive rice-shrimp

farming with low density. Due to the small farming area (<2 ha/household) in Soc Trang farmers tend

to increase the stocking density in order to increase profitability in the production of shrimp in the

rice-shrimp system (this model only appears in Soc Trang, for Tra Vinh this model is applied to semi-

intensive whiteleg shrimp farming). In this model, shrimp are farmed in the dry season (January-August)

and rice cultivation (sowing or transplanting) in the rainy season (September-December). General

characteristics of this farming model are the use of salt water in the dry season for shrimp, and fresh

water from the Hau River and rainfall for rice cultivation.

Field Designs

Field design for rice-shrimp farming comes in two forms:

Traditional form: Surrounding ditches and the original field surface in the middle of the field, non-

lowered field ground. Surrounding ditches have width of 2.5 to 3.0m with depth from 1.0 to 1.2 m.

Excavated soil is used to build the banks higher to keep water in the field at depth of 0.3 to 0.5 m. This

field can be improved and desalinized easier to grow rice in the rainy season, and has lower

construction costs. However, the shallow depth of field water level leads to low stocking density, and

the small water volume causes water quality issues.

Fields with lowered ground: A soil layer of 30-40 cm (depending on the area of the field) is removed

from rice field surface to build banks (field is 1.2-1.5 m deep). This form of field allows higher stocking

density but is more difficult to desalinize in the rainy season.

Figure 8. Field with lowered ground (left) and original field with surrounding ditches (right)


In this form of farming system, most households have no settling ponds to treat water for farming

process. Therefore the water supply depends largely on water quality of the canal and river system.

In general, two forms of field have similar shrimp-farming techniques. Due to higher investment on

lowering the field with water deeper than traditional surrounding ditches, farmers stock shrimp at

higher densities to gain greater productivity and profitability, however this brings higher risk.

Shrimp PL and Stocking Density

Shrimp PL used for farming includes tiger shrimp and whiteleg shrimp. Shrimp PL is stocked one time

in the farming pond. Shrimp size of PL15 (1.5–2.0 cm length) is stocked at the density of 10-15PL/m2.

After harvesting the rice crop, fields are improved, cleaned, lime applied, dried, banks are reinforced

and equipment such as pumps and paddlewheel aerators are used. Tiger shrimp PL mainly originate

from MRD provinces Bac Lieu, Ca Mau and South Central provinces Ninh Thuan and Binh Thuan.

Results of a shrimp semi-intensive farming study in Soc Trang Province by Vo Nam Son (2011) showed

that shrimp productivity has a close relationship with the area of surrounding ditches, and has no

relation with total farming area and time of stocking.

Table 3. Technical specifications of semi-intensive rice-shrimp model in Soc Trang Province,

Vietnam

Criteria

Stocking density

(PL/ m2)

(AVG, STD)

Survival rate

(%)

(AVG, STD)

Productivity

(kg/ha)

(AVG, STD)

Proportion of surrounding

ditches (%):

≤ 20%

>20%

5.4 ± 1.7

7.5 ± 3.7

43.1 ± 23.1

36.0 ± 23.5

622 ± 366

740 ± 676

Field area (m2):

< 7.000 m2

≥ 7.000 m2

≥ 15.000 m2

5.8 ± 2.5

7.3 ± 2.9

6.1 ± 4.0

46.2 ± 24.0

42.9 ± 24.1

42.4 ± 19.2

722 ± 394

925 ± 826

574 ± 218

Stocking time:

15/12-15/02

16/02-15/03

16/03-26/04

7.3 ± 2.7

6.9 ± 3.9

5.8 ± 2.2

42.0 ± 19.5

37.9 ± 20.9

51.5 ± 25.1

841 ± 601

682 ± 653

848 ± 603

Source: Vo Nam Son (2011)

Comparison of semi-intensive tiger shrimp (TS) and whiteleg shrimp (WLS) farming in rice-shrimp

systems in Kien Giang (Phu Van Thai, et al. 2015) showed no difference in the pond area used, the ratio

of surrounding ditch area, field water depth and stocking times. However, there is a difference in

stocking density, PL size, feed conversion ratio, feeding time until first harvest, commercial shrimp size

at harvest and shrimp yield. WLS is usually stocked at higher density, at smaller PL size, has an earlier

harvest and higher shrimp yield, but the product is a smaller commercial size, and has a higher feed

conversion ratio than TS.


Table 4. Technical specifications of semi-intensive models: TS-Rice and WLS-Rice in Kien Giang

Province, Vietnam

Item TS-Rice

(n=65)

(AVG, STD)

WLS-Rice

(n=62)

(AVG, STD)

Farming land (ha) 1.66±0.84 1.37±0.51

Proportion of surrounding ditch

area (%)

21.0±2.57 21.5±3.41

Width of surrounding ditches

(m)

3.36±0.59 3.36±0.51

Water depth of surrounding

ditches (m)

1.43±0.18 1.46±0.13

Water depth of main field (m) 0.52±0.15 0.57±0.08

Rate of household with PL

quarantine (%)

7.7 12.9

PL size 16.0±2.7 11.9±0.6

Stocking density (PL/m2/crop) 7.8±2.2 13.4±3.8

Stocking density first time 4.4±1.3 7.5±2.5

Stocking times (time/crop) 3.49±0.62 3.74±0.68

Percentage of household with PL

nursery (%)

26.2 25.8

Nursery area compared to total

pond area (%)

6.72±2.45 7.17±1.27

PL density in nursery pond

(PL/m2)

93.4±43.6 118±32.1

Time of PL in nursery (day) 20.5±3.3 16.0±4.4

Percentage of households using

commercial feed (%)

89.2 95.2

FCR 0.45±0.19 0.67±0.24

First harvesting time (day) 125±9.3 100±17.3

Survival rate (%) 13.1±3.6 33.0±11.7

Shrimp size at harvest (g/shrimp) 31.2±2.8 14.0±1.7

Productivity (kg/ha) 320±111 632±311

Source: Phu Van Thai et al (2015)

Food and Feeding

Due to high density of shrimp stocking, shrimp are fed immediately after stocking with high quality

industrial foods at a frequency of 2-3 times/day, and feeding amount is 2.5-6 percent of the total shrimp

body weight, depending on the shrimp growth stage. Depending on type of shrimp (TS or WLS),

stocking density, natural food density and mixed fish in the pond, the average feed conversion ratio

ranges from 0.45-0.9, and up to 1.2-1.6 in the high density model (15-30 shrimp/m2).

The number of households that use a PL nursery in their pond is low, at only 25 percent. The PL

nursery and shrimp stocking density of TS is commonly lower than WLS. The productivity of WLS is

higher than TS while harvesting size of TS is generally larger than WLS.


Pond Management and Shrimp Harvest

During the semi-intensive shrimp farming, normally the conventional aeration system is used solely for

the purpose of providing more oxygen to the pond after one month stocking. However, as the pond

water is not changed frequently, the aeration system can be used to collect waste and control the

temperature stratification and salinity of the pond when the weather changes. After 4-5 months of

stocking, survival rate ranges from 30-70 percent. Shrimp are harvested at the size of 25–40 pcs/kg.

Harvested shrimp are sold to purchasing agent in shrimp farms. Shrimp yield fluctuates according to

locality and shrimp PL. In Kien Giang shrimp productivity achieved 350-940 kg/ha, while in Soc Trang

from 700-3000 kg/ha.

Rice Farming

In the rainy season after desalination, the base of the field is used to grow rice. The common rice

varieties are ST (120 days to harvest) and OM (90-100 days to harvest). Rice yield ranges from 5-8

tons/ha. Generally these varieties have higher salt tolerance than rice varieties in fresh water. However

when salinity increases at the end of the crop (evaporation of water and an incomplete dike system

causes saline water issues), rice yields can decrease or can be completely lost.

4.1.2 Economic, Social and Environmental Effectiveness

Economic Effectiveness

For tiger shrimp (TS-Rice), the average return of approximately 54 million/ha/year, in which profits

from shrimp farming is around 30 million (55 percent of total profit). For whiteleg shrimp, profit gained

is higher than tiger shrimp, averaging 69.1 million/ha/year, in which profit from shrimp farming is around

55 million (79.1 percent of total profit). This difference is mainly due to investment level, stocking

density of whiteleg shrimp (20-30 PL/ m2) higher than tiger shrimp (10 PL/m2).

Table 5. Cost Benefit Analysis of TS-Rice and WLS-Rice in Mekong River Delta, Vietnam (million

VND/ha/year)

Item TS-Rice WLS-Rice

1. Gross benefit 93.60 133.60

- Shrimp 60.00 100.00

- Rice 33.60 33.60

2. Total costs 39.50 64.50

- Shrimp crop 30.00 55.00

- Rice crop 9.50 9.50

3. Net benefit 54.10 69.10

4. B/C ratio 1.37 1.07

Source: Study findings (2015)

Considering profit ratio (profits/costs), profit from TS-Rice (1.37) is higher than WLS-rice (1.07). The

reason is that despite bringing more profits, investment costs for WLS are higher. This is also evident

in rice farming. In rice-shrimp farming, rice production costs are much lower than the intensive rice

production as people reduce the cost of fertilizers and plant protection products, resulting in higher


ratio of profit/cost (2.53). It was reported by Soc Trang Extension Center in 2014 that the ratio of

profit/cost of intensive rice farming is 0.78-1.24, much lower than rice farming in rice-shrimp model.

Table 6. Cost Benefit Analysis of TS-Rice model and WLS-Rice model in Kien Giang Province

(million VND/ha/year)

Item TS-Rice

(AVG, STD)

WLS-Rice

(AVG, STD)

Total cost (TC) 27.96±6.74 51.28±14.06

Total revenue (TR) 71.55±25.78 87.36±43.69

Profit return (PR) 44.44±22.78 36.05±34.50

Average total cost (ATC) 99.40±54.20 99.70±49.90

B/C ratio 1.58 0.70

Source: Phu Van Thai, et al. (2015)

Comparison with study results of Phu Van Thai et al. in Kien Giang, the average profits from rice-

shrimp farming with TS is 44.44 million VND/ha, and WLS 36.05 million VND/ha, which are lower

figures than the findings of this study for the MRD. However, B/C ratio for TS-rice model in Kien Giang

Province is higher (1.58).

In addition to income from shrimp and rice, many households in Long Hoa Commune and Hoa Minh

commune (Tra Vinh Province) have income from crab that are stocked with shrimp. Average income

from crab is about 20 million VND/ha.

Social and Environmental Effectiveness

For the regions with small farming areas, previously there was only one rice crop during the rainy

season, resulting in ineffective production and difficult life of the local people. The semi-intensive rice-

shrimp model has contributed to job creation and significant income growth for people. The study

results show that household income increased by 51-55 percent compared to previous intensive rice

farming. Besides, compared to intensive/semi-intensive shrimp farming areas, maintaining the rice crop

contributes to ensuring food security for households and is “risk insurance" in case of shrimp crop

failure. At the same time, rice cultivation is seen as a natural filtration system to help minimize the risk

of disease outbreaks in shrimp. Rice-shrimp cropping also contributes to improving the efficiency of

land use, and reduce land degradation.


Figure 9. Survey results of farmers that agree/disagree that the rice-shrimp farming model is

resilient to climate change impacts, Mekong River Delta, Vietnam.

In the assessment of the awareness about the rice-shrimp model under the impacts of climate change

in My Xuyen district (Soc Trang Province), shrimp monoculture farming households and rice-shrimp

farming households were interviewed. The results show that over 80 percent of interviewed

households agreed, (of which 34 percent completely agreed), that the rice-shrimp farming model is a

smart adaptive model in the face of climate change. Respondents recognized that it ensures food

security, is adaptive and resilient, and reduces emissions.

4.1.3 Advantages and Limitations

The advantages of the rice-shrimp model: High shrimp yield, deep water level favorable for shrimp

farming. This region is endowed with large volumes of fresh water in the rainy season from Hau river

systems and direct precipitation, thus rice cultivation is less troubled by water shortages. The salt water

canal system from the My Thanh River system is able to meet the demand of shrimp ponds in the dry

season.

Limitations: High risk of shrimp disease, increased soil salinity due to less rain and higher temperatures

creating difficult conditions for rice cultivation, difficult to mechanize rice harvesting due to small area

and deep muddy field. Irrigation systems remain weak, with sedimentation and lack of separate

irrigation systems to supply fresh water (for rice) and salt water (shrimp). Diseases are highly

contagious because of unqualified shrimp farming ponds such as industrial shrimp farming areas (no

settling ponds, treatment ponds).

4.2 Semi-intensive Two Shrimp-One Rice Farming

4.2.1 Specification

In recent years, whiteleg shrimp (Litopenaeus vannamei) has brought many benefits to the intensive

farming system in the MRD. Due to the short farming period (60-90 days) until harvesting size, ability

1.61% 1.56% 1.59%

14.52% 10.94% 12.70%

50.00% 53.13% 51.59%

33.87% 34.38% 34.13%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Mono-shrimp Rice-shrimp Total

% r

ele

van

t h

ou

sho

lds

Completely agreed Agree Don't know/No idea Disagreed Completely disagreed


to grow in low salinity, acceptable price, many models of semi-intensive TS-rice farming have turned

to 2WLS-rice such as in Soc Trang and Tra Vinh provinces. Depending on the annual price of tiger

shrimp and whiteleg shrimp, farmers will choose which is potentially more profitable to stock. In case

of tiger shrimp crop failure (due to shrimp disease) and a short time remaining in the shrimp farming

season, whiteleg shrimp is an option for replacement stocking.

Field Design

Features of whiteleg shrimp field design are similar to semi-intensive rice-shrimp farming. Suitable pond

area ranges from 1000-3000 m2. The floating pond form is generally applied with reinforced banks and

complete aeration system. However, the removal of soil in this form also increases the risk of alum

escape (exposes hidden alum layer), making it difficult to manage pH level in the shrimp pond water

and difficult for first rice crop cultivation due to low pH level. Lime should be added to raise the pH

level in the field.

Figure 10. Lowered field ground to create semi-intensive rice-shrimp farming field


Whiteleg shrimp is cropped from January to July (2x WLS crops); and rice cropped from August to

December. Most WLS PL stocked originates from large companies such as Minh Phu, CP, and Vietnam

- Australia with clear origins and features certification for being tested and being free of some common

dangerous diseases (Specific Pathogen Free - SPF). In addition, some small scale hatcheries in South

Central provinces, Ca Mau and Bac Lieu also provide PL to the farmers. PL12 is stocked at a density of

15-60 PL/m2; in Tra Vinh stocking density is 80-100 PL/m2 (1 WLS – 1 rice crop).

Farmers that apply intensive and semi-intensive farming models, follow industrial shrimp feeding

methods. Shrimp are fed with commercial feed with amount of 2.5 to 6.5 percent of the total shrimp

body weight per day and feed consumption ratio (FCR) ranges from 1.0 to 1.2.


Pond Management and Shrimp Harvest

During the crop, farming techniques to limit the change of shrimp pond water are applied to limit the

spread of disease as well as to save salt water when the supplying water supply (river, canal) has a low

salinity level. After 80-90 days, shrimp are harvested the first time with yield ranging from 1.5-10 ton/ha

and survival rate ranging from 50-80 percent. Some whiteleg shrimp farming households reuse water

from the first crop for the second crop (if the first crop grows well without disease). This is due to the

low salinity level of river and canal water, which is not suitable for raising whiteleg shrimp.

Rice

Rice varieties used in this model are OM (85-90 days to harvest), ST (120 days) or Nang Keo (120

days). Rice yield ranges from 4-6 ton/ha.

4.2.2 Economic, Social and Environmental Effectiveness

Economic Effectiveness

Due to investment requirements and intensity, generally wealthy households only practice this farming

model. Survey results show that the total annual income from this model is approximately 236 million

VND/ha, of which income from shrimp accounts for 89 percent (209.65 million VND). Compared with

the semi-intensive one shrimp-one rice model and the improved extensive farming model, income from

this farming model is much higher. However, the profit ratio of this model is lower, at 0.67, due to

higher investment in farming ponds, shrimp PL and feed.

Table 7. Cost Benefit Analysis of WLS-WLS-Rice semi-intensive model in MRD, Vietnam

(million VND/ha/year)

Factor WLS-WLS-Rice

(AVG, STD)

1. Total benefit 235.88±158.75

- Shrimp 209.65±148.98

- Rice 26.23±11.40

2. Total cost 149.63±128.95

- Shrimp crop 138.17±101.47

- Rice crop 11.46±9.49

3. Profit 100.56±111.13

4. B/C ratio 0.67


In terms of the rice crop, income and profit ratio are lower than other rice-shrimp models. Firstly,

households that practice this model place less focus on the effectiveness of the rice crop and employ

rice farming only to improve the pond environment after the shrimp crop. Secondly, due to two

continuous shrimp crops, salinity levels and degradation of the pond base soil are higher, affecting the

productivity of the rice crop.


This model offers higher income compared to other rice-shrimp models, however this requires higher

investment costs and higher risk. According to the study of Le Phuong Mai et al (2015), high stocking


density in Soc Trang Province, plus unusual changes of weather, causes high rates of losses to farmers

in Soc Trang, 21.9 percent and 15.6 percent for shrimp and rice respectively, higher than in Bac Lieu

and Ca Mau.


Advantages: Higher yield than tiger shrimp, short farming time, easier and more suitable to be applied

to small ponds while still achieving high production.

Limitations: Lack of salt water in the early rainy season (end of the second shrimp crop), higher risk of

disease than improved-extensive shrimp farming, high technical requirements and stricter management

of farming pond. Alum is an issue in some newly built ponds and farmers are unable to cultivate rice.

Farming ponds and supplementary areas (settling pond, treatment pond, and nursery area) have not

met the requirements of this farming model, leading to susceptibility to contagious disease.

4.3 Semi-intensive Farming with 1 Shrimp Crop and 1 Sedge Crop

This semi-intensive farming model has been applied for two years in areas with high salinity, difficult

irrigation conditions and where desalination entirely depends on natural rainfall. The increasing impacts

of climate change (changed rainfall patterns, higher temperatures) challenge rice cultivation due to the

difficult desalination process after the shrimp crop. Therefore, farmers are adapting by planting different

varieties of sedge grass instead of switching to intensive shrimp farming. This improves the environment

of the pond/field and creates more food for the next shrimp crop. The reason given by most farmers

is that intensive shrimp farming is unsustainable.

In addition, some households combined planting sedge with feeding brackish fish such as tilapia and

barramundi to raise income. However this farming method is only temporary. In the long term, people

may switch to rotational rice-shrimp farming practices with one shrimp crop and other aquaculture

options, such as brackish fish. This model brings greater economic efficiency and reduces risk. In the

semi-intensive farming model with 1 shrimp crop (TS or WLS) and 1 rice crop which may suffer from

saline intrusion, high salinity, prolonged heatwave, freshwater shortage which are all inappropriate for

rice planting, rice-shrimp farmers could switch to one shrimp crop and planting sedge.

According to farmers, the purpose of planting sedge is to improve the pond environment and to

increase sources of organic feed materials as well as density of natural food in the pond. In addition,

the sedge grass helps regulate pond temperature in hot weather.


Figure 11. Fields with sedge grass planted as an alternative to rice after shrimp crop in Bac Lieu

and Kien Giang provinces, Vietnam

There are similarities between farming models of 1 shrimp crop – 1 rice crop and 2 shrimp crops – 1

rice crop, including: Field specifications, shrimp PL, stocking density, food and feeding, pond

management and harvesting. However, farmers can also increase income by taking advantage of their

pond area during the rainy season to stock other aquaculture species like tilapia, barramundi,

mudskipper or crab.

The semi-intensive model with 1 shrimp crop and sedge grass is not applied continuously over the

years, but usually by planting sedge one year (due to environmental difficulties described above) and

growing rice the following year. The duration of shrimp farming in this model can be extended. Little

rainwater and freshwater from rivers and canals is required for desalination. Sedge grass is planted to

provide shrimp feed and improve the pond environment. However, sedge generates less or no financial

profit, and it can be costly to clear sedge before replanting rice.

The farming model of switching between rice and sedge is derived from the one rice-one shrimp model.

However, climate change leads to increasing salinity, especially in areas with poor irrigation

infrastructure, creating inappropriate conditions for rice cultivation. Therefore, economic benefit is

only derived from the shrimp crop, similarly to the one rice-one shrimp farming practice. Sedge planting

is only a temporary environmental solution and does not bring financial profit. Therefore, farmer

income generated from this model is lower than that in the semi-intensive farming with 1 shrimp crop

and 1 rice crop.

4.4 Improved Extensive Shrimp Farming and 1 Rice Crop

4.4.1 Specifications

The improved extensive TS-rice farming has been widely applied in the MRD of Vietnam since 2000.

Over 15 years of development, this model has experienced many technical changes and improvements

as well as development and expansion into intensive rice farming areas with low yields in Kien Giang,

Ca Mau and Bac Lieu provinces. This model’s common feature is a large farming area (average 2-3

ha/household).


Field Design

Figure 12. Improved extensive rice-shrimp fields, without PL nursery (left) and with PL nursery

made from soil (right). Mekong River Delta, Vietnam, 2015

The pond in this model is usually manually built and is surrounded by ditches. The area of ditches

accounts for 10-30 percent of the pond, with width 2-3 m and depth 1.0-1.2 m. However the

topography of this area is commonly low-lying land so the field embankments are small and are

susceptible to leaking. Such a large pond area requires high cost for investment in field embankments,

or other farming works. Only some households have a PL nursery area. According to Le Thi Phuong

Mai et al. (2015) in Ca Mau Province only 18.2 percent of households use a PL nursery, while 58.8

percent do in Bac Lieu.


In this model, the shrimp crop is usually from January to August and rice crop September to December.

At the end of December, farmers harvest rice, combining this with field improvement (eliminating fish,

applying lime, pumping water into pond and fertilizing) to prepare for the shrimp crop. TS PL15 is

provided by agents and nursery farms with PL origin from hatcheries in the MRD and the South Central

Coast. In the first stocking, PL density is 2-9 PL/m2, then farmers stock additional PL after 1.5-2 months

with stocking density of 1-2 PL/m2, depending on shrimp survival rate. At the end of the shrimp crop,

farmers can stock bigger PL (PL after nursing PL15 for 25-30 days, at a size of 6,000 PL/kg) in the farming

pond, in order to shorten shrimp farming time before the next rice crop.

Food and Feeding

In this model, most farming households do not directly feed PL, especially during initial months (1-3

months of stocking). However if the PL survival rate is high, natural food for shrimp will not be

sufficient, leading to slow growth. Farmers can supplement industrial food to enhance shrimp growth

to reach marketable size. When shrimp density is low, farmers maintain the fertilizing practice to

provide nutrients for the development of natural food.


Pond Management and Shrimp Harvesting

In the improved extensive rice-shrimp farming system, shrimp are not fed industrial food so pond water

tends to lack nutrients. Thus, the process of pond management primarily includes: maintaining water

level and managing proportion of natural food, checking water quality by looking at water color,

temperature and salinity in the farming field. Farming fields are not always properly managed so

managing pests and disease is a challenge.

Table 8. Technical specifications of improved extensive rice-TS in Soc Trang, Bac Lieu and Ca

Mau provinces, Vietnam

Factor

Sóc Trăng

(n = 32)

(AVG,

STD)

Bac Lieu

(n = 34)

(AVG,

STD)

Cà Mau

(n = 33)

(AVG, STD)

Average

(n = 99)

(AVG, STD)

Total area of farm (ha) 1.8 ± 1.6 2.4 ± 1.7 2.3 ± 1.2 2.2 ± 1.5

Area of rice land (ha) 1.1 ± 1.0 1.8± 1.5 1.7 ± 1.2 1.7 ± 1.2

Proportion of surrounding ditches (%) 36.9 ± 20.0 29.9 ± 16.6 31.0 ± 21.6 32.6 ± 19.5

Households with settling pond (%) 37.5 0.0 6.1 14.1

Water depth (m) 1.0 ± 0.2 1.0 ± 0.2 1.0 ± 0.2 1.0 ± 0.2

Households improving field annually (%) 96.9 88.2 66.7 83.8

Households with PL nursery (%) 43.8 58.8 18.2 40.4

Stocking density (PL/m2) 8.9 ± 4.5 2.7 ± 1.7 3.3 ± 3.4 4.9 ± 4.3

Harvesting time (days) 152 ± 27 102 ± 17 111 ± 18 121 ± 30

FCR 1.2 ± 0.4 0.2± 0.1 0.2 ± 0.5 0.9 ± 0.6

Water change frequency (times/crop) 4.8 ± 7.5 5.7± 4.3 5.4 ± 4.2 5.3 ± 5.5

Chemicals, medicines used (type/crop) 2.5 ± 1.0 0.8 ± 0.7 1.7 ± 0.7 1.7 ± 1.1

Harvested shrimp size (pcs/kg) 46.0 ± 27.5 32.7 ± 4.4 34.8 ± 6.9 37.7 ± 17.2

Source: Le Thi Phuong Mai et al (2015)

Since most farmers applied the method of repeatedly stocking shrimp, after 2 months shrimp are

harvested (scattered) by capturing large shrimp by net. The shrimp survival rate in this model widely

fluctuates, but is commonly low (<20 percent) with the yield of 320-700kg/ha (harvested shrimp size

of 30-40 pcs/kg). According to Nguyen Thanh Long and Nguyen Thanh Phuong (2010), in Soc Trang

Province the average stocking density of rice-TS model is 7.74 shrimps/m2 with the yield of 919 kg/ha,

generating a profit of 28.6 million VND/ha.

Research on improved extensive rice-TS and rice-WLS model in An Bien and An Minh district, Kien

Giang province showed that: farming area of the model ranges from 1.37-1.66 ha/model, the area of

surrounding ditches takes up 21-23.6 percent, and water depth is 1.43–1.46 m. Shrimp density is 2.18

shrimp/m2 and survival rate is 32.5 percent. Harvested size and productivity of shrimp is 14-31.2

g/shrimp and 232-632 kg/ha. In general, harvested TS are larger in size than WLS, while WLS have

higher productivity.


Rice Farming – Recommendations from Nguyen Thanh Tuong (2013)

After harvesting shrimp, farming field is desalinized (primarily by rainfall) to grow rice. Common rice

varieties are OM and Mot Bui Do with yields of 4.0 to 4.2 ton/ha. Due to low rice yield and profit,

some farmers have farmed some other aquaculture species for intercropping in rice fields such as giant

freshwater shrimp or crab to increase their income. Giant freshwater shrimp yield ranges from 150 to

300 kg/ha. However, just as with intercropping shrimp with the rice-shrimp model, the use of

agricultural chemicals to treat rice diseases should be considered carefully to combine with those with

biological origin. Rice varieties used in this model should be strongly disease-tolerant in order to limit

the use of agricultural herbicides and pesticides.

According to Nguyen Thanh Tuong (2013), rice varieties with a low or medium amylose level and

protein proportion of higher than 9 percent include: OM5629, OM6677, and OM6377. Rice varieties

with high salt-tolerance and long grain (6.6 to 7.5 mm), medium amylose level (20-24 percent) and

protein proportion of higher than 9 percent are: Nàng Thơm muộn, Tài Nguyên (TG), Một Bụi Đỏ, and

Rạch Giá. The crop cycle lasts from August to December annually. Prior to each crop, a period of 15-

30 days is required for land improvement.

Soil preparation: At the beginning of the rainy season, water is drained 9-20 times over 15-20 days for

desalination and the soil is submerged for 7 days. During the soil tillage period, farmers should add

calcium in the form of CaSO4 (gypsum) at rate of 550 kg/ha or CaO (lime) at 450 kg/ha.

Sowing: Direct sowing with seed generally occurs in May and June, requiring 100-120 kg/ha for high-

yield rice; or 40-60 kg/ha for winter rice. Transplanting occurs in late June or early July with 50-60 kg

of seed needed to establish 1000 m2 of young rice plants to transplant into a 1 ha field.

Water management: At the end of the shrimp crop, famers should take advantage of rainwater and

channel water to keep water depth at 10-20 cm, preventing water leakage or salinization.

Before sowing rice, it is recommended to drain the field of water 5-7 days. After sowing, farmers slowly

pump water into the field with depth equivalent to the height of rice, and keep a water depth of 10-20

cm during rice growth process. 7-10 days prior to harvesting, farmers dry the field by pumping out.

Fertilizer application for 1 ha of cultivated rice: 300-350 kg phosphate; 60-100 kg urea; 100-130 kg of

NPK (20-20-15).

Disease/pest prevention: Apply integrated pest management measures (IPM).

4.4.2 Economic, Social and Environmental Efficiency

Economic Efficiency

Rice farming has a positive economic impact on the efficiency and effectiveness of shrimp farming as

well as that of the whole rice-shrimp system as compared to the intensive shrimp farming model

(without rice). The practice of the rice-shrimp model will bring higher profit compared to the model

of 2 rice crops. Efficiency in capital investment in this model is 1.5 times higher than the two rice crop

model (cost benefit ratio fluctuates from 1.67 to 2.59, mean = 2.29). The rice-shrimp model requires

more labor, thus is suitable to large families which have extra time in the dry season.


Table 9. Cost Benefit Analysis of improved extensive rice-shrimp model in Mekong River Delta,

Vietnam (million VND/ha/year)

Item Bac Lieu Ca Mau Kien Giang

1. Gross profit 77.80±25.78 54.20± 29.0 81.40±43.69

- Tiger Shrimp 30.30±10.9 33.40±14.05 37.10±13.80

- Giant freshwater shrimp 16.50±0.50 - 15.20±0.0

- Rice 31.00±0.8 20.80±0.8 29.10±0.20

2. Total costs 22.40±0.30 15.10±0.50 30.50±24.30

- Tiger Shrimp 7.70±0m 3 8.30±4.54 14.20±0.59

- Giant freshwater shrimp 4.00±0m 3 - 3.50±2.53

- Rice 10.7±0.53 6.80±0.56 12.60±0.58

3. Net profit 55.40±0.60 39.10±0.3 50.90±10.6

4. B/C ratio 2.47 2.59 1.67


Economic efficiency of the improved extensive rice-shrimp model is different between localities

depending on the level of technical expertise of farming households. With giant freshwater shrimp

being intercropped in the rice crop, household income in Kien Giang and Bac Lieu has increased

significantly (77.80 and 81.40 million/ha/yr respectively), which is much higher than than in Ca Mau

(54.20 million/ha/yr). Despite the highest average total income, Kien Giang also has higher investment

cost in TS crop, resulting in lower average profit than in Bac Lieu.

Considering the margin on investment capital, the farming model in Ca Mau brings the highest net

profit (B/C ratio of 2.59) which is 1.5 times higher than in Kien Giang (1.67). This result is consistent

with the study of Phu Van Thai et al. (2012), which revealed a B/C ratio of 1.65 in Kien Giang.

Table 10. Cost Benefit Analysis of TS-rice intercropped with giant freshwater shrimp (GFS) in

Bac Lieu Province, Vietnam (million VND/ha/year)

Item GFS TS Rice Total

Total cost 7.8±5.4 32.4±13.9 30.0±13.80 70.3±30.6

Gross profit 32.0±14.8 85.6±42.2 70.0±33.90 188.0±84.6

Net profit 24.4±11.5 53.1±28.9 40.0±20.3 118.0±54.8

B/C ratio 3.12 1.63 1.33 1.68

Source: Huynh Kim Huong et al. (2015)


In terms of social and environmental impacts, the improved extensive model is considered the most

sustainable of all rice-shrimp farming models in the MRD. It requires a low level of investment, and is

suited to the financial conditions and current farming techniques of rural households.

The risk level of this model is also much lower than other rice-shrimp farming models. A study by Le

Phuong Mai et al. (2015) revealed that the percentage of households suffering losses in improved


extensive rice-shrimp in Ca Mau and Bac Lieu provinces was about 3-6 percent, significantly lower than

that of the semi-intensive rice-shrimp farming model in Soc Trang (15.1-21.9 percent).

This improved-extensive rice-shrimp model uses low stocking densities and low additional feed

requirements. This model is considered resilient to climate change impacts in terms of ensuring food

security, being better able to adapt to extreme weather events and reduce emissions.


The model is easy for farmers to apply due to low technical requirements and suitability to natural

conditions with small investment and lower risk than semi-intensive farming. However the model

depends on annual weather events (rainfall) to function efficiently and there is still a lack of active and

separate irrigation systems supplying fresh water for rice (in rainy season) and salt water for shrimp (in

dry season). Salinity level tends to increase after years of model application, requiring more freshwater

or longer desalination.

Quality of salt-tolerant rice varieties is generally low, resulting in low market prices. In addition, shrimp

productivity and survival rate are low. Shrimp consumption is mostly through retail, and it is difficult

for farmers to directly access large purchasing agents or processing factories. As a result, shrimp in this

model have no trademark despite its excellent quality.

Farming fields are generally of poor quality, embankments are low, small, and prone to leaks; water

depth is shallow, causing high temperature during daytime and low temperatures at night. Shrimp

mostly concentrate in the surrounding ditch, which raises shrimp density and reduces the availability

of natural food.


5. CHALLENGES TO THE

DEVELOPMENT OF RICE-SHRIMP

IN THE MEKONG RIVER DELTA

The rice-shrimp system in the MRD is considered an economically efficient model. It is not only suitable

to environmental conditions of rice fields impacted by salinity but also appropriate to the limited

investment capacity of the majority of local farmers. However the rice-shrimp system in the MRD faces

challenges in its aim for sustainable development.

5.1 Climate Change

The MRD is one of the most severely affected areas by climate change, where impacts include saline

intrusion, heatwaves, and extreme weather events. The temperature in the past 50 years has increased

by 0.7°C and the rainy season comes later (Le Sam, 2010, Nguyen Thanh Phuong et al. 2012). According

to Vietnam’s Ministry of Natural Resources and Environment (2011) in the scenario of medium

emissions (B2), by 2100 there will be reduced rainfall and an increase in average temperature of 2-3°C,

the number of day with temperature over 35°C will increase by 10-20 days, and sea-level rise of 62-82

cm will be experienced in Ca Mau and Kien Giang provinces. More saline intrusion, prolonged

heatwaves, short rainy seasons and drought are experienced in MRD provinces, which has and will

cause negative impacts on aquaculture activities. If there are no adaptation efforts, profit from intensive

and semi-intensive shrimp farming will fall by 130 million VND/ha by 2020 and 950 million VND/ha by

2050 (World Bank 2010).

In addition to the impacts of climate change, the MRD is impacted by hydroelectric dam construction

in the upstream region. This causes low river flood levels, reduces freshwater in the flood season for

desalinization of fields after the shrimp crop, and does not provide fresh water to lower salinity levels

suitable for rice farming. These changes, together with limited salt tolerance of existing rice varieties,

are challenges to maintain rice cultivation in some rice-shrimp farming regions. The current rice

varieties can tolerate the maximum salinity level <5 percent. Even in the flowering stage, a salinity

concentration of 2-3 percent has a serious impact on rice yield.

Rice-shrimp farming in Ca Mau and Bac Lieu provinces suffer from these challenges more severely than

other provinces in the MRD. Because of climate change impacts, some areas have switched to the

shrimp-sedge model or intensive shrimp model with 2 shrimp crops per year. These models have

adaptation advantages, however they are challenged in terms of decreased efficiency (shrimp-sedge

model) and reduced sustainability (two intensive shrimp crop model).

Planting sedge after the shrimp crop aims to improve and clean the field, protect the environment,

which contributes to disease prevention. However, sedge planting generates low or no income,

affecting farmers’ livelihood.


Intensive shrimp farming with 2 shrimp crops generates a higher income than rice-shrimp model.

However the field environment, which is not cleaned and improved, is quickly degraded, leading to

increased risk of shrimp disease, affecting the sustainability of shrimp farming.

The impacts of climate change have and will have an increasing influence on the rice-shrimp systems in

the MRD. This challenge requires urgent solutions regarding rice varieties and adaptive, sustainable

farming models to ensure rural people's livelihood.

5.2 Shrimp PL and Farming Technique

Aquaculture species in rice-shrimp regions, such as tiger shrimp, whiteleg shrimp, and giant freshwater

shrimp and crab, are produced locally or imported from outside provinces. They meet the demand of

PL in terms of quantity and farming time. However, PL quality, especially TS and WLS, is not guaranteed.

Farmers generally have to use PL of unclear origin, low quality and no quarantine, leading to low survival

rates. Stocking density is not suitable for the food availability and poorly managed pond environments,

which increases PL cost and reduces shrimp yield. Therefore, it is essential to ensure that farmers are

supplied with certified, high quality shrimp PL.

Giant freshwater shrimp is farmed more often in the rice-shrimp system compared to the past. Farming

all-male giant freshwater shrimp brings greater profit than gender-mixed shrimp (faster growth, larger

harvesting size). However, at present the number of hatcheries and their production capacity on

gender-mixed giant freshwater shrimp PL, and especially all-male PL, is limited and unable to meet

demand. The demand for giant freshwater shrimp PL is not only large in coastal brackish rice-shrimp

regions but also in freshwater rice-shrimp regions in Dong Thap, An Giang, Can Tho and Hau Giang.

Currently, giant freshwater shrimp PL in the MRD is mainly imported from China and Thailand. The PL

quality is not controlled and farmers have to buy PL at a high price.

There are various forms of shrimp farming in the rice field: rice field with ditch area accounting for 10-

30 percent area of the field, extensive shrimp farming, improved extensive shrimp farming, monoculture

and mixed farming. Yield ranges from 300 to 600 kg/ha depending on stocking density, feeding and field

environment. The common farmer perception is to raise yield by increasing ditch area, increasing

stocking density and applying mixed farming. However, the optimal stocking density of PL and ratio of

cultured species in each model have not been identified. As a result, biological productivity of the

system has not utilized and the production system is at risk of overuse.

The nursery stage before stocking is an important technical step in order to enhance survival rate of

shrimp. It also ensures more accurate stocking density and overcomes limitations caused by the farmer

habit of supplementary stocking. However due to a lack of technical guidelines on standard nursery

area, appropriate stocking density, farming techniques and correct nursery duration, many farmers

experienced failure in the nursery stage or witnessed shrimp loss and slow growth. This has limited

the expansion of the nursery as a technical solution for many rice-shrimp regions.

Even though farmers have been trained, inconsistent farming techniques, lack of technical materials,

standards and guidelines (including on field design, nursery construction, stocking density) have

hampered training effectiveness and aquaculture extension, and reduced the efficiency of shrimp

farming.


Due to the high profit from shrimp farming, farmers tend to increase stocking density and to switch

from one shrimp crop - one rice crop farming to two specialized shrimp crops in order to increase

production. This risks exceeding the environments’ capacity and is a challenge to the sustainable

development of rice-shrimp system in the MRD.

Water resources have a strong influence on the efficiency of rice and shrimp farming. Water quality is

a key factor in selecting aquaculture species, farming season, water treatment and water management.

It is essential to conduct water monitoring for aquaculture in MRD in general and in the rice-shrimp

area in particular, which will serve as an information base for improved water management. Currently

the environmental monitoring network in the rice-shrimp region is outdated and restricted by a lack

of staff, equipment and funding. Farmers also receive no support in selecting water supply, conducting

water treatment and managing production.

5.3 Rice Varieties

Rice varieties farmed in the rice-shrimp system are diverse and include: ST, Một bụi đỏ, Nàng Keo,

OM5451, OM2017, OM6377 and OM6677, which are widely grown in the MRD and produce high

yields with salinity concentration below 5 percent.

Existing rice varieties face environmental challenges including prolonged heatwaves, short rainy season,

low rainfall, low flooding level, increasing and prolonged salinity in the field, and fresh water shortages.

These adverse weather changes are increasingly obvious in the MRD. In 2015, prolonged heat, low

rainfall and a low level of flooding resulted in insufficient freshwater for rice fields, and therefore the

high salinity killed many rice crops.

The current rice varieties grown in the MRD cannot withstand high salinity (>5 percent). As a result,

farmers in some areas have replaced rice with sedge grass to maintain a favorable environment for

shrimp farming. However, sedge cultivation does not provide a source of income to the farmer.

Nguyen Cong Thanh (2014) tested 15 rice varieties in rice-shrimp areas of Kien Giang, Bac Lieu and

Ca Mau provinces. Results showed that 15 rice varieties grown in Kien Giang and Bac Lieu have the

yield of at least 3.5 ton/ha, while in Ca Mau only 9 out of 15 rice varieties had a yield of 3.5 ton/ha, and

6 out of 15 rice varieties produced zero yield. The major cause is high salinity level of ponds in Ca Mau,

over 6 percent. The investigation of rice growing households showed 70.9 percent of households in

Bac Lieu Province are not satisfied with the existing rice varieties, while this figure was 50 percent in

Ca Mau and 38.8 percent in Kien Giang. People said that the existing rice varieties are not adequately

salt-tolerant, have low productivity and a long growing period.

The existing rice varieties are unable to grow when salinity in farming fields is high (> 5 percent), thus

farmers in some areas have replaced rice with sedge to maintain a favorable environment for shrimp

farming. However sedge planting only has environmental benefits for the pond, not financial benefits.

Most of the rice varieties currently grown in the rice-shrimp system have a growing period from 110

to 120 days, and the winter crop is 150 days. The varieties with the shortest growing period - 95 to

100 days - are OM7347, OM2514, OM2017 and HS182. Meanwhile in the MRD, the trend of prolonged

heatwaves, late rain, and low rainfall has shortened the time period with suitable salinity levels for rice

production. This system requires salt-tolerant rice varieties with short growing periods.


5.4 Infrastructure

For over 40 years, the investment in irrigation infrastructure has provided the MRD in general and

coastal areas in particular with very effective irrigation systems. They are able to control saltwater,

reserve freshwater in the dry season, improve drainage and de-alkalization capacity, improve soil,

expand production land, and contribute to the shift from intensive rice production into aquaculture.

The MRD has a total length of 1,057 km of dykes. This includes the sea dykes and estuary dykes. In

addition, surrounding dykes and embankment systems were built along primary and secondary canals,

effective in preventing high tide, reserving freshwater, combined with traffic roads. 582 coastal sluice

gates have been built in the coastal areas of MRD.

The government has invested in the irrigation system to supply saltwater and freshwater, and drain

extra water. At present, there is 50,000 km of water channels at all levels, including 6,700 km of primary

canal, 14,000 km of secondary canal. The provinces of Kien Giang, Ca Mau and Bac Lieu have the

highest density of secondary canals in the MRD.

However irrigation infrastructure was built with the primary aim to serve rice cultivation. The canal

systems for water supply and drainage are combined, leading to limitations in the distribution of

freshwater and saltwater. This also contributes to the fluctuating quality of water used in aquaculture.

Most rice-shrimp farming fields feature surrounding ditches and raised embankments. These are part

of the significant changes in field construction for rice-shrimp farming compared to the initial

development period. However, in many rice-shrimp areas, construction of the field has affected shrimp

farming efficiency and caused shrimp death especially in hot months. Causes of this include

inappropriate design of the field and the ditch/embankment system, small and shallow surrounding

ditches, low and leaking embankments, and low pond water depth.

In many areas, infrastructure for rice-shrimp farming has had inadequate investment, due to the focus

on irrigation infrastructure for rice cultivation. In addition, due to limited funding, some sluice gates

have not been built, many canals have not been dredged, upgraded and repaired, leading to salinity

issues in rice cropping. Some rice-shrimp areas in Kien Giang, Bac Lieu, Ca Mau and Tra Vinh have also

experienced contaminated water sources causing shrimp disease. The lack of saltwater for shrimp

crops and freshwater for rice crops, and a complete reliance on natural rainfall can result in freshwater

shortages needed for field desalinization.

In addition to the above limitations, the existing irrigation infrastructure in MRD faces challenges arising

from climate change, including sea level rise, late rainy season, low rainfall, and low flood levels on the

Mekong River system. These impacts expose shortcomings in freshwater/saltwater drainage and supply

as required by the rice-shrimp area.

Currently there are 5 ongoing projects on infrastructure investment for aquaculture in MRD, of which

only 2 projects provide direct service for rice-shrimp development in Ca Mau, with only a small rice-

shrimp area benefited (approximately 8,000 ha). Other projects are mainly for intensive and semi-

intensive shrimp farming areas. Of 2 infrastructure projects started in 2015 and 12 infrastructure

projects serving aquaculture investment proposals in the Mekong Delta to 2020 (Directorate of Water

Resources, 2015), only 3 projects propose to invest in infrastructure for rice-shrimp areas in Kien


Giang, Ca Mau and Bac Lieu. Ongoing and proposed projects are modest in scale and number. The

challenge to control saltwater and supply freshwater as required by rice-shrimp farming remains, which

restricts the sustainable development of aquaculture including rice-shrimp farming in MRD.

5.5 Current Policy

Specific policies for rice-shrimp have not been issued by the Vietnam Government. However some

policies relating to production support, investment in and consumption of agricultural products,

including those from rice-shrimp farming have been issued. These include:

The Government issued Decision 142/2009/QD-TTg on supporting seed, livestock and aquaculture

breeding for production recovery in areas damaged by natural disasters and disease epidemics. Shrimp

farmers receive support of 3-5 million VND/ha with over 70 percent damage, and 1-3 million VND/ha

with 30-70 percent damage. Support may be cash or in kind with equivalent value. For purebred rice,

support of 1 million/ha is provided to households with over 70 percent damage, and 500,000 VND/ha

to households with 30-70 percent damage. For cross-bred rice, support of 1.5 million VND/ha and

750,000 VND/ha is applied to 70 percent and 30-70 percent damage respectively.

This support helps reduce the burden on farmers caused by unpredictable circumstances. However,

the limited funding (majorly from local budget), plus complicated procedures for identifying

beneficiaries and receiving support, has led to late and inefficient support for farmers. In addition, the

support is often given to large-scale damages so small-scale farming households have little chance to

receive support for shrimp disease or severe salinity.

Regarding irrigation fee rates in agriculture, in the MRD the fee rate as well as water supply are lower

than those in other regions. Decree 67/2012/ND-CP specified that the irrigation fee in the MRD is

equivalent to 60-75 percent of the rate in Red River Delta with the same type of water supply.

To protect paddy fields and to ensure food security, the Government issued Decree 42/2012/ND-CP

on land use and management for rice cultivation, specifying that conversion of rice paddy land be in line

with approved land use planning and to be authorized by competent authorities. Rice farmers are

entitled to the support of 1 million VND/ha/year for their commitment to monoculture rice-farming,

and 500,000 VND/ha/year for other types of rice farming (E.g. 1 rotation cash crop with 1 rice crop).

Due to the high profit from shrimp farming or issues from salinity intrusion or lack of freshwater, many

households spontaneously switched from rice-shrimp to specialized shrimp farming. This breaks

government planning regulations. The policy on supporting affected rice farmers with cash shows the

government’s concern to rice farmers, however, its effectiveness should be reconsidered. Many farmers

have a small rice field area and the corresponding support makes little impact. The process of support

distribution and receipt as well as labor cost for this procedure is significant, and leaves inadequate

cash for other farm investments. Therefore, it is suggested that this financial support should be changed

from direct support to farmers to community investment at the commune level for construction and

improvement of rice-shrimp infrastructure.

To determine the role of agricultural cooperatives and promote linkages between agricultural

production and consumption, the Congress approved Law 23/2012 on Cooperatives. The Government

also promulgated Decree 193/2013/ND-CP on specifying some articles in the Law on Cooperatives,


which defined cooperatives take priority in infrastructure development investment for production,

processing and consumption, and priority in concessional loans to develop production and services.

The Prime Minister approved Decision 62/2013-TTg promulgating a policy on encouraging cooperation

development, linking agricultural production with consumption, and developing large trial fields.

Accordingly, the Government partly supports the cost of infrastructure planning and construction

(roads, electricity, and irrigation) and field improvement. Farmers are fully supported with the cost for

training and technology transfer, and receive a one-time support of 30 percent of the cost of purchasing

high quality rice seed. However, these policies are being applied differently to rice-shrimp regions in

the MRD province. Tra Vinh does not apply this policy in developing large rice-shrimp fields because

the current policy is believed to be applied to specialized rice fields only.

For many years, the Vietnam Government has made efforts to use various financial sources to invest

in irrigation works, focused seed producing zones and so on, and aimed at developing aquaculture

including rice-shrimp. However due to limited capital compared to investment demand, some

construction projects are being implemented slowly, affecting irrigation management in rice-shrimp

regions.

In order to mobilize social resources for investment, the Government approved Decision 71/2010/QD-

TTg on piloting public-private partnership investments in two selected project groups: Transportation

services construction, renovation, management; and national projects in group A, B, and C. Decree

15/2015/ND-CP on public-private partnership encourages investment in rural and agricultural

infrastructure, services, linkage of production, processing and consumption. However, these policies

have not been practical for agriculture in general and for the rice-shrimp system in particular, due to

the requirements on project planning and direct commitment from farmers. The small-scale and

uncoordinated farming activities of rice-shrimp in the MRD adds to this difficulty.

5.6 Production Management

Shrimp post larvae plays an important role in the productivity and economic efficiency of the rice-

shrimp system. In MRD provinces, MARD stipulate that shrimp PL must have clear origin and

quarantine. Provinces have invested in facilities and equipment for PL quarantine testing. However in

reality, shrimp PL is commonly sourced from unclear origins without quarantine. The fact that farmers

are used to buying local, cheap shrimp PL, added to the limited capacity of management authorities, is

a key reason for poor quality production management.

All local authorities prepare rice-shrimp development plans. However in reality, the approved planning

has not been well managed. In some localities, farmers spontaneously switch from specialized two rice

crops to one shrimp-one rice crop as in Bac Lieu and Ca Mau; or switch from one shrimp-one rice

crop to specialized two shrimp crop as in Tra Vinh and Soc Trang. Such situations have led to increasing

salinization, adversely affecting intensive rice farming areas. Most localities do not impose sanctions

against this action, but generally accept it and adjust their planning.

According to regulations of MARD, extensive and improved extensive brackish shrimp farming areas

are not allowed to farm whiteleg shrimp. However whiteleg shrimp has been farmed in many rice-

shrimp areas in Soc Trang, Tra Vinh, Kien Giang, Ca Mau, Bac Lieu. The slow implementation of a

comprehensive evaluation of biodiversity conservation, economic and environmental efficiency of


farming whiteleg shrimp in extensive and improved extensive farming areas in general and rice-shrimp

farming in particular, has caused confusion in production management.

5.7 Production Organization

All surveyed provinces have developed a rice-shrimp development plan, however there are challenges

to management of the plans. Profit from shrimp farming is higher than from rice farming, leading to the

spontaneous practice of rice-shrimp farming in intensive rice farming regions and a shift from one rice—

one shrimp crop to two specialized shrimp crops, which causes salinity issues in specialized rice regions.

Small-scale household farming is common in rice-shrimp regions. Cooperatives and cooperative groups

have been formed but are limited in number and are small-scale, thus limitations and difficulties in

production have not been solved yet, including:

Shrimp PL, food and fertilizer are bought from various sources and traders, leading to bad quality and

high price of these products.

Shrimp are harvested at the household scale in small quantities, therefore labor for shrimp collection

is inefficient. In spite of the presence of good quality seafood processing enterprises, shrimp in the rice-

shrimp region is often sold at lower prices than in intensive and semi-intensive shrimp farming regions.

Dispersed production at the household scale has caused disagreements in production and management

in some farming areas. The mix between fields specialized for two shrimp crops and rice-shrimp fields

has made it difficult to manage water supply and salinization carried over from shrimp farming fields to

rice fields.

Mechanization in rice-shrimp farming faces difficulty due to deeply lowered fields with wide and deep

surrounding ditches. The base of rice-shrimp farming fields subside easily, meaning they are unable to

be hardened by drainage and drying, and possess a highly alkaline soil. These factors have hindered the

mechanization of tillage, sowing and rice harvest.

5.8 Market

Key products from rice-shrimp are: rice, tiger shrimp, whiteleg shrimp, giant freshwater shrimp, crab

and some fish species. Tiger shrimp and whiteleg shrimp are partly consumed domestically while the

majority is processed for export. Giant freshwater shrimp and crab is mainly consumed in country.

Crab is exported fresh to China. Mixed types of fish, mainly tilapia and local fish types, are consumed

domestically as human food or fresh food to animals (crocodiles).

Tiger shrimp and whiteleg shrimp from rice-shrimp regions is regarded to be of good quality, safe and

not infected by antibiotics, thus the product is trusted and selected by seafood processing and exporting

businesses. However, due to small-scale household production, dispersed harvest, and difficulty in

shrimp collection, farmers have not been benefited from good prices equivalent to shrimp quality.

Giant freshwater shrimp is mainly sold within Vietnam without any difficulty in the consumer market.

However, the development of the market for giant freshwater shrimp should be under concern as giant

freshwater shrimp farming area is expanded in the MRD.


Despite the good quality of shrimp from rice-shrimp areas with typical cultivating characteristics, there

has been no trademark or brand. Some shrimp processing and exporting enterprises (Minh Phu, Thien

Phu) have started to develop their trademark. However, the effort of companies alone is not adequate

to develop a shrimp trademark; this requires the effort of farmers, businesses and management

authorities.


6. SOLUTIONS FOR SUSTAINABLE

RICE-SHRIMP FARMING IN MRD

6.1 Rice-shrimp Adaptation to Climate Change

The models of shrimp-sedge or two shrimp crops are viable adaptations to high and prolonged salinity,

late rainy season with less rainfall, low level river floods, and a lack of freshwater for the rice crop.

However in regards to sustainable development, these models face challenges of effectiveness (shrimp-

sedge model) and sustainability (two shrimp crop model).

Sedge grass planting after the shrimp crop aims to improve and clean the pond environment after

farming shrimp, protect the environment and limit diseases, and enhance the effectiveness of shrimp

farming. Farmers are plant various types of sedge to replace rice. Cultivating sedge generally results in

little to no profit, and farmers have to clean up the sedge to stock shrimp. It is necessary to find an

alternative kind of sedge or seaweed to improve and protect the environment as well as provide income

for farmers. Some kinds of seaweed, which can grow in water environment with salinity of 15-20

percent, temperatures of 20-30°C, and water depth >0.5m, should be used to replace rice in salinized

land inappropriate for rice cropping. Methods to clean up sedge that require less labor should be

studied.

Intensive shrimp farming with two crops brings higher income than one shrimp crop, but the field

environment is not improved and is quickly degraded, increasing the risk of shrimp disease, affecting

the sustainability of rice-shrimp farming. It is essential to develop a sustainable farming process for the

two shrimp crop model. In addition, it is suggested to develop and replicate the model of shrimp-fish

farming (tilapia, mudskipper) with environmental sustainability as an alternative to the two shrimp crop

model.

The rice-shrimp farming model with PL nursery brings significant benefits and should be replicated in

the MRD of Vietnam. There should be instruction and training on the criteria including nursery area,

design, stocking density, care and nursery duration.

The model of stocking many species at the same time (tiger shrimp, crab) in the shrimp crop and

stocking giant freshwater shrimp in the rice crop should also be encouraged for development.

However, to optimize the effectiveness of this model, there must be research on identifying the ideal

proportion of stocking for each species in different environmental conditions.

6.2 Policy Solutions

Policies to support production, linkages between production and consumption, and development of

large fields for the rice-shrimp model should be applied. The Circular of MARD in guiding the

implementation of Decision No 62/2013-TTg on policies to encourage cooperation and linkage of

production and consumption, and construction of large sample fields should be adjusted soon, in order

to expand application to the rice-shrimp areas.


Current policy on direct cash support for rice farmers under the provisions of Decree

No.42/2012/ND-CP has limited effectiveness. This should be changed as based on rice farming areas in

each community and region. Funds from the national budget should be used at the commune level to

support the community to build, improve or upgrade infrastructure works (e.g. culverts, drainage) for

effective rice-shrimp farming.

In the context of a limited budget, inadequate infrastructure for rice-shrimp production, public-private

partnerships in investment and resource mobilization from people for investment in rice-shrimp area

is of great importance. The Government has promulgated Decree 15/2015/ND-CP on public-private

partnerships, encouraging investment in rural infrastructure, agriculture, services, linking production,

processing and consumption of products. However, these policies have not been realized in agriculture

in general and rice-shrimp farming in particular, due to the requirements on project planning, direct

committed funding required from households, and particularly the prevalence of unsystematic individual

farming activities of rice-shrimp farmers. These obstacles need to be removed and at the same time

regulations and guidelines should be developed consistent with the conditions of the available labor

force, dispersed capital of households, limited project development capacity to mobilize resources from

the farmers in construction, and renovation of water irrigation works in the area of rice-shrimp farming.

Currently loan policy is based on the mortgage, and the provision of capital for production investment

for farming households and cooperatives should be completed. In addition to the mortgage-based

lending, consideration is needed for the specific conditions when loans may be given based on trust.

6.3 Management Solutions

There should be management measures to address the situation of PL without clear origin and

quarantine. In addition to capacity building for quarantine facilities, strengthening the control of the

management agencies for PL quality, and changing methods of managing PL quality are essential. MARD

(the Minister has assigned full responsibility to Veterinary Department, with the Directorate of

Fisheries to collaborate) should soon issue a circular on the regulations to manage the shrimp

hatcheries to ensure quality and pathogen-free status. This Circular should be developed so that shrimp

PL hatcheries must meet the requirements for such facilities, disease-free production processes, quality

control of PL, and managing the output quality from the hatcheries. Change is needed from the current

quarantine method which has displayed inadequate resources and poor performance.

Farmers have been spontaneously switching from intensive two rice crop farming to one shrimp-one

rice farming, or switching from one shrimp-one rice farming to two shrimp crop farming. This

conversion leads to increased salinization, affecting the intensive rice areas. In addition, the impacts of

climate change and saline intrusion, change of flooding, change of rainy season, and hot weather have

affected many rice-shrimp and intensive rice regions, requiring rice-shrimp planning in MRD to be

reviewed and adjusted accordingly as a basis for appropriate and effective investment in infrastructure

and production organization.

Climate change has and will continue to seriously affect the MRD region with many dams expected to

be built on the Upper Mekong River, prolonged heatwaves, further and wider saline intrusion, greater

frequency and severity of freshwater shortages, which all require reconsideration of agricultural

development planning in MRD. It is suggested to review and adjust the Government plan to narrow


the intensive rice farming area, and expand the rice-shrimp and intensive aquaculture area. The

objective of MARD from 2016 to 2030 to expand the rice-shrimp area in the MRD is consistent with

the pressure of climate change impacts. However, it is necessary to reconsider the rice-shrimp planning

to reach 200,000 ha by 2020 and 250,000 ha by 2030 to develop proper planning. This is because

current areas where farmers spontaneously converted from rice farming to shrimp intensive and rice-

shrimp farming has not been properly calculated. Furthermore, more severe climate change impacts

are expected to decrease the area of land appropriate for rice cultivation and increase the area suitable

for conversion to rice-shrimp farming.

6.4 Infrastructure Solutions

Firstly each farming household should be required to construct or improve fields to match rice-shrimp

farming requirements. This includes: sufficiently wide and deep ditches around the field; high and leak-

proof banks to contain enough water for shrimp farming; and appropriate nursery area to nurse PL

before stocking.

Water irrigation canals and ditches should be renovated and dredged, embankments upgraded to

prevent water spill and culverts built under embankment level 2 and 3 depending on each region, to

proactively drain saltwater before and reserve freshwater during the rice crop.

It is necessary to build sluice gates to prevent salt water intrusion and retain freshwater in some rice-

shrimp regions of Kien Giang and Ca Mau. The rice-shrimp region bordering intensive rice areas should

build separate systems to ensure freshwater/saltwater separation by embankments and dykes.

Climate change in the MRD will cause late and short rainy seasons with less rainfall, and low flood

levels on the Mekong River system. Therefore investing in freshwater storage systems, and freshwater

supply systems for some regions should also be considered for selection.

Environmental monitoring for aquaculture in general and rice-shrimp in particular should receive more

investment. At present, in the MRD of Vietnam, the Center for Environment and Disease Monitoring

in Aquaculture – CEDMA (under RIA II) with qualified human resources and equipment and localities

have built capacity in environmental monitoring for aquaculture. However local resources (human,

equipment and funding) remain limited. Furthermore, the poor linkage, coordination and cooperation

between CEDMA and localities cause limited effectiveness and do not meet the requirements of

aquaculture production. The environmental monitoring network for aquaculture in the MRD, including

rice-shrimp farming, should be strengthened.

In order to promote quality of investment in infrastructure in the rice-shrimp region, there should be

a long-term land use planning for the entire MRD, agreed to by varied sectors and localities to serve

as a base for the development of irrigation infrastructure planning. Such planning should take into

account climate change and the development of the central and upper Mekong River.

6.5 Model Replication / Aquaculture Extension Solutions

The model of the PL nursery in a separate area, which brings marked benefit in increased survival rates,

reduced PL costs and enhanced shrimp productivity, should be extended to the whole region.


Crab PL nursery before stocking into main pond should also be developed.

In order to effectively replicate the models, it is necessary to be implemented on a wide scale, in

addition to the demonstrations and trainings, the team of extension workers to provide direct technical

support to farmers is very important. Currently there are local extension staff (Commune Aquaculture

Officers); however it is necessary to mobilize final year aquaculture students to be involved in technical

assistance activities, model transfer and replication. Detailed technical guidelines on the field designs

and nursery also need to be developed and disseminated to farmers.

In 2015, MARD approved the aquaculture extension project to develop rice-shrimp models in MRD

over 2016-2020, chaired by RIA II. The consistent replication of the model in all localities, support

seed, PL, feed and model construction to farmers should be reconsidered in term of effectiveness. Each

model is suitable to the specific conditions of environment, economics, and society, thus the

widespread replication of a single model is inappropriate. The policy on providing material support for

farmers to build the model is not effective due to limited resources. The most effective support for

farmers is technical support through trainings, farm management guidelines that are practical and easy

to apply, and access to technical field assistance. For the effectiveness of the MARD 2016-2020 project,

it is essential to carry out a review, and adjust the objectives, contents, and implementation methods

with the participation of rice-shrimp stakeholders. After this review the project may be implemented

sustainably.

6.6 Production Solutions

The organization of production in rice-shrimp areas should be promoted. Organizing cooperatives in

rice-shrimp regions is needed urgently. The cooperatives, with large rice-shrimp fields, will overcome

the current limitations due to small scale production Current limitations are: PL, feed, fertilizer are all

bought from various sources leading to low quality and high cost; and dispersed shrimp harvest by

households, small harvest quantity, costly collection leading to lower prices. Independent production

by households causes disagreement in production, water resource management, and salinization of

land.

Linkage between rice-shrimp farmers and businesses supplying PL, production materials and

manufacturing/processing businesses will bring significant benefits, contributing to reduced production

costs and stable and profitable consumption of products.

To realize the organization of production in the rice-shrimp area, in addition to reviewing and

supplementing necessary legal provisions, the efforts of local authorities and managers in initiating and

supporting communities to select leaders of cooperative groups and the process of implementation is

of great importance.

6.7 Market and Trademark Development Solutions

Shrimp from rice-shrimp areas are of good quality, with high market demand, but have not been

trademarked. It is recommended to develop a trademark and promote shrimp from the rice-shrimp

region in the international market.


For shrimp produced from the rice-shrimp system, there should be only one trademark for the whole

MRD region. Development of the shrimp trademark, product promotion and market development

requires persistence, planning and consistent objectives. In addition to the efforts of businesses, the

support of the Vietnam Government for legal provisions, production organization and market

development is required.

Giant freshwater shrimp products require market research and development, particularly for the

export market.

Fish (tilapia, bass) and seaweed may become important aquaculture products in the near future in the

rice-shrimp areas, especially in areas affected by climate change impacts to extend the model of two

shrimp-fish crops. Therefore the expansion of the consumer market for these products should also be

considered.

6.8 Research Solutions

6.8.1 Current Research

There have been several studies related to the MRD rice-shrimp systems, the key studies in period

2010-2015 were:

Study to improve productivity and efficiency of rice-shrimp farming model in Ca Mau peninsula region,

Ministry level scientific and technology topic (MARD) was chaired by Research Institute for Aquaculture

II. Research to develop and promote rice-shrimp model with high productivity and efficiency in terms

of economic- social and environment in Ca Mau Peninsula regions (Ca Mau, Bac Lieu and Kien Giang).

The ACIAR project to improve the sustainability of rice-shrimp farming systems in Vietnam’s MRD

over 2013-2017. It is implemented by the cooperation of three Australian universities (University of

New South Wales, Griffith University, Charles Sturt University) and three institutions in Vietnam (RIA

II, Cuu Long Rice Research Institute, and CTU). The project field research site is in Ca Mau.

The study to analyze the technical aspects and the financial performance of the giant freshwater shrimp

with rice crop and tiger shrimp crop in the brackish areas of Bac Lieu province. Huynh Kim Huong,

2015, University Thesis, Can Tho University.

Research on rice varieties and rice cultivation techniques for rice-shrimp farming model in Bac Lieu.

Vo Nam Son, 2011, Agriculture PhD thesis, Can Tho University.

Assessment study on climate change impacts and adaptation options in tiger rice-shrimp in MRD. Le

Thi Phuong Mai, 2015, University thesis, Can Tho University.

6.8.2 Priority Research

Based on current challenges in management techniques, economic efficiency, production organization,

markets and climate change faced by MRD rice-shrimp systems, the following research should be

prioritized for implementation in order to ensure sustainable development.

Research addressing technical challenges:


Identify the maximum and optimal capacity of sustainable shrimp farming in rice-shrimp

systems. The research results should be the basis to direct and guide farmers to optimize the

field design, stocking density, the percentage of mixing species (shrimp, crab), shrimp

production in different environmental conditions, minimize disease risks, protect the

environment, gain the highest economic efficiency.

Improving technology, enhancing production capacity of giant freshwater shrimp in MRD.

Despite successful production of giant freshwater shrimp PL in artificial conditions, the

production technology remains unstable. There is limited capacity to produce large quantities

of shrimp PL, PL availability is concentrated in a short time, unable to meet PL demand, and

dependent on foreign imports. Research is urgently needed to improve giant freshwater shrimp

PL production technology, and produce large volumes of PL.

All-male giant freshwater shrimp farming has an advantage over mixed gender shrimp farming,

RIA II in Vietnam succeeded in producing all-male giant freshwater shrimp by iRNA technology

to create the “fake” female giant freshwater shrimp, however production capacity is limited,

while demand for all-male giant freshwater shrimp is significant. There is an urgent need for

research to improve technological processes (pilot production project) and rapidly conduct

technology transfer and training for local hatchery centers and businesses.

Full assessment of the impacts on biodiversity conservation, economic and environmental

efficiency of extensive/improved-extensive whiteleg shrimp farming areas in general, and rice-

shrimp in particular for management and production direction.

Research on climate change adaptation:

Limitations of the existing rice varieties include low salt tolerance (<5 percent), they not meet

the demand for rice cultivation in the severe salinity conditions, prolonged heatwave and

freshwater shortage. It is necessary to conduct research on highly salt-tolerant rice varieties

which grow well in field conditions of salinity >5 percent.

Research on development of short-term salt-tolerant rice varieties: Due to the shortage of

freshwater and saline intrusion, the appropriate time period for rice farming is short. There

should be research on creating salt-tolerant rice varieties with a short farming time period to

grow in rice fields.

Regarding regions that are unable to continue rice-shrimp farming due to saline intrusion and

shortage of freshwater (Kien Giang, Ca Mau, Bac Lieu), there must be research to develop

sustainable models of intensive two shrimp crops or shrimp-fish rotation.

Seaweed, especially Gracilaria tenuistipitata, may become a potential alternate crop to rice after

the shrimp crop. It is necessary to test the adaptability of certain types of seaweed in

environmental conditions of coastal MRD regions. The potential success of this model could

open up the diversity of aquaculture in coastal areas, improve sustainability of shrimp farming,

and address the limitation of no profit from sedge in the shrimp-sedge model in highly saline

areas.

Research on production organization:

It is recommended to conduct research on production organization. Currently there are some

rice-shrimp cooperative models in Soc Trang, however they have limited roles and operations.

The development of cooperative models will overcome difficulties in management of farming


areas, planning, PL quality, reduce PL costs and input materials, concentrated harvest and

selling, linkages with processing manufacturers for export to enhance shrimp value in rice-

shrimp areas of MRD.

Research on branding and market promotion:

Research on developing a brand and promoting markets for shrimp from rice-shrimp areas of

MRD based on quality indicators of safe commercial shrimp, environmentally and socially

responsible production, clear origin and traceability.


7. RECOMMENDATIONS AND

SUGGESTIONS

Considering the current situation, identification of shortcomings, challenges in terms of techniques,

environment, management, policies and climate change impacts on the sustainable development of rice-

shrimp in the MRD, the authors recommend:

7.1 The Ministry of Agriculture and Rural Development, Vietnam

To immediately review and adjust planning for intensive rice farming areas, intensive aquaculture areas

and rice-shrimp area in MRD of Vietnam.

To urgently issue a Circular on management of brackish water PL hatcheries to ensure veterinary safety

and pathogen-free.

To approve and implement the project on sustainable development of rice-shrimp in MRD over 2016-

2020, in a timely manner.

To review and adjust the contents and implementation method of aquaculture extension projects to

develop rice-shrimp in MRD over 2016-2020.

To propose to the Prime Minister to adjust the Decision 142/2010/QD-TTg on policy mechanism

supporting seed, livestock and aquaculture seed to recover production of areas affected by natural

disasters and epidemics; and the Decision 62/2013-TTg on policy encouraging partnership

development, linkage between production and consumption, development of large sample fields.

To propose the Government to modify Decree 42/2012/ND-CP on management and use of rice land,

and Decree 15/2015/ND-CP on public-private partnership.

7.2 The USAID Mekong ARCC Project

To continue supporting the development of rice-shrimp in MRD with the following activities:

- Replicating the model of shrimp PL nursery before stocking: compilation of technical guidelines,

training plans and technical assistance to farmers during application.

- Developing rice-shrimp models and compiling the technical documentation for models which are

sustainable and adaptive to climate change.

- Developing production models through establishing a large field research trial, trademark and

market development for rice-shrimp products in the MRD of Vietnam.


Figures 13 & 14:

The USAID

Mekong ARCC

Project provided

training and

Standard

Operating

Procedure

handbooks to

rice-shrimp

farmers in Kien

Giang Province in

2014-2015.


REFERENCES

Brennan D., Preston N., Clayton H. and Be T. T. 2002. An evaluation of rice-shrimp farming

systems in the Mekong Delta.

Decision 142/2009 / QD-TTg, 2009. The Decision by the Prime Minister on mechanisms and

policies to support crops, livestock and aquaculture to recover production in areas damaged by natural

disasters and diseases.

Decision 71/2010 / QD-TTg, 2010. The Decision by the Prime Minister on pilot investment in

public-private partnership.

Decision 62/2013 / QD-TTg, 2013. The Decision by the Prime Minister on policies to encourage

development cooperation, linking production with consumption of agricultural products, building large

sample field.

Decree 67/2012 / ND-CP, 2012. Vietnam Government. Regulated irrigation fee rates for agricultural

production.

Decree 42/2012 / ND-CP, 2012. Vietnam Government. Regulated land management and land use

of rice farming land.

Decree 193/2013 / ND-CP, 2013. Vietnam Government. Specifically regulated some articles of the

Law on Cooperatives.

Decree 15/2015 / ND-CP, 2015. Vietnam Government. Regulated investment under public-private

partnerships.

Department of Agriculture and Rural Development of Kien Giang, 2015. Current situation

and development orientation of tiger shrimp-rice rotation in Kien Giang Province. Report from the

conference ‘Solutions to improve efficiency and develop rice-shrimp farming in the Mekong Delta’: Kien

Giang, September 23, 2015.

Department of Agriculture and Rural Development in Ca Mau, 2015. The situation and

solutions to develop rice-shrimp in Ca Mau. Report from the conference ‘Solutions to improve

efficiency and develop rice-shrimp farming in the Mekong Delta’: Kien Giang, September 23, 2015.

Department of Agriculture and Rural Development of Bac Lieu, 2015. Report from the

conference ‘Solutions to improve efficiency and develop rice-shrimp farming in the Mekong Delta’: Kien

Giang, September 23th, 2015.

Department of Agriculture and Rural Development, Soc Trang, 2015. Shrimp-rice farming:

Development status and solutions. Report from the conference ‘Solutions to improve efficiency and

develop rice-shrimp farming in the Mekong Delta’: Kien Giang, September 23, 2015.


Department of Agriculture and Rural Development of Tra Vinh, 2015. Current situation and

development orientation of rice-shrimp farming in Tra Vinh province.

Directorate of Fisheries, 2015. Current situation and development orientation of shrimp-rice

farming in the Mekong Delta. Report from the conference ‘Solutions to improve efficiency and develop

rice-shrimp farming in the Mekong Delta’: Kien Giang, September 23, 2015.

Directorate of Irrigation, 2015. The status of irrigation infrastructure, planning and irrigation

investments for aquaculture in coastal region of the Mekong Delta. Report from the conference

‘Solutions to improve efficiency and develop rice-shrimp farming in the Mekong Delta’: Kien Giang,

September 23, 2015.

Economics and Planning Institute of Fisheries, 2015. Planning for brackish water shrimp farming

in the Mekong Delta 2016-2020 with a vision to 2030. Report from the conference ‘Solutions to

improve efficiency and develop rice-shrimp farming in the Mekong Delta’: Kien Giang, September 23,

2015.

Hoang Minh Truong, Nguyen Thai Binh and Tran Trong Tan, 2012. Technical status, financial

efficiency and impact of the policies on the rice-shrimp model in the Mekong Delta.

Hoang Minh Truong, Tran Hoang Tuan and Tran Trong Tan, 2013. Comparison of

production efficiency between traditional and improved rotation rice-shrimp systems in Kien

Giang Province. Journal Science CTU 28 (2013): 143-150.

Huynh Kim Huong, Le Quoc Viet, Do Thi Thanh Huong and Tran Ngoc Hai, 2015. Technical

and Financial Analysis of rice-shrimp and brackish water shrimp rotation in Bac Lieu. The article was

accepted for publishing in the Scientific journal of Can Tho University.

Interdisciplinary Team 249 (Ca Mau), 2015. Draft report on examination and evaluation of the

current status of shifting land use from agriculture and forestry to rice-shrimp farming rotation in Ca

Mau province

Kakonen M., 2008. Mekong Delta at the Crossroads: More Control or Adaptation? Ambio. Vol. 37

No.3.

Le Canh Dung, 2012. The impact of rice farming to shrimp farming from economic indicators of

rice-shrimp model in coastal areas in the Mekong Delta. Scientific journal in 2012: 69-77. Can Tho

University.

Le Sam, 2010. Monitoring report on salinity in the Mekong Delta 2010. Southern Institute of Water

Resources Research.

Le Thi Phuong Mai, Vo Nam Son, Tran Ngoc Hai, Duong Van Ni, 2015. Assessment of climate

change impact and response measures in rice-shrimp rotation in the Mekong Delta. The article was

accepted for publishing in the scientific journal of Can Tho University.


Ministry of Agriculture and Rural Development, 2015. Conclusion of the Deputy Minister Vu

Van Tam at the meeting on solutions to improve efficiency and development of shrimp-rice farming in

the Mekong Delta. Announcement No. 7907 / TB-BNN-VP, September 25th, 2015.

Ministry of Natural Resources and Environment, 2011. Scenarios of climate change and sea

level rise for Vietnam.

Ministry of Fisheries 2006. Report on Evaluation of Aquaculture Development Program 2000-2005

and approach to 2010.

Nguyen Cong Thanh, 2014. Study on improving the productivity and efficiency of the rice-shrimp

rotation system in the Ca Mau peninsula.

Nguyen Thanh Tung, 2007. Evaluation report on the switch from saline intrusion affected rice

paddy land into semi-intensive shrimp farming.

Nguyen Thanh Tuong, 2013. Rice selection and rice cultivation techniques for the rice-shrimp

system in Bac Lieu Province. PhD thesis in Agriculture. Can Tho University.

Phu Van Thai et al, 2015. Techinical aspects and economic-efficiency of Tiger shrimp (P. monodon)-

Rice and Whiteleg shrimp (P. vannamei)-Rice models in Kien Giang Province.

Preston N. & H. Clayton (eds), 2003. Rice-shrimp farming in the Mekong Delta: Biophysical and

socioeconomic issues. ACIAR Technical Reports No. 52e.170 p.

Research Institute for Aquaculture No.2, 2015. The development of the rice-shrimp system in

the Mekong Delta 2016-2020 (Draft 3). Project Proposal.

Research Institute for Aquaculture No.2, 2015. Development trends of the rice-shrimp farming

system in the Mekong Delta and lessons learnt. Report at the conference ‘Solutions to improve the

efficiency and develop shrimp-rice farming in the Mekong Delta’: Kien Giang, September 23, 2015.

Vo Nam Son, 2011. Development of suitable cropping calendars for Tiger shrimp culture in the

Mekong Delta, Vietnam. PhD thesis, Asian Institute of Technology, Bangkok, Thailand.

development of rice-shrimp farming in mekong river delta, vietnam

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