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Anwara Begum and S. M. Nazmul Alam

Caritas Fisheries Program
1/C, 1/A, Pallabi. Mirpur-12
Dhaka-1221, Bangladesh

Begum, A., and S.M.N. Alam. 2002. Social and economic impacts of shrimp disease among small-scale, coastal farmers and communities in Bangladesh. p. 191-200. In: J.R. Arthur, M.J. Phillips, R.P. Subasinghe, M.B. Reantaso and I.H. MacRae. (eds.) Primary Aquatic Animal Health Care in Rural, Small-scale, Aquaculture Development. FAO Fish. Tech. Pap. No. 406.


Outbreaks of viral disease causing mass mortalities of tiger shrimp, Penaeus monodon, have occurred in Bangladesh since 1995 and have resulted in a dramatic decline in shrimp yields. Many small-scale farmers have fallen into serious economic difficulty after incurring losses from white spot syndrome virus (WSSV). The coastal communities are greatly concerned about the virus, which has been crippling shrimp farming and the economy. Participatory Rural Appraisal (PRA) has been used in three affected areas to collect qualitative information, particularly on people's perception of the impacts of shrimp disease. This paper discusses the findings of PRA in terms of people's realisation of the extent of diseases, the causes of loss, and the impacts on livelihood.


The sustainability of shrimp farming has become a major concern among small-scale, coastal farmers in Bangladesh, as the sector has experienced widespread disease problems for four or five consecutive years. In Bangladesh, diseases like black spot, soft shell, external fouling and broken appendages occurred only infrequently and were not though to have significant impacts on shrimp production. However, in April 1994, an outbreak of disease of cultured black tiger shrimp (Penaeus monodon) occurred in semi-intensive farms in Cox's Bazar, southeastern Bangladesh, where it caused losses of 50-60%. Later, the disease occurred in southwestern Bangladesh, where it severely affected small-scale farms practising low stocking density, resulting in great economic loss.

Production and export of shrimp play a dominant role in the economy of Bangladesh; the shrimp sector is the third largest earner of foreign currency. Black tiger shrimp are being cultured in about 115,000 ha of brackishwater farms under extensive (90%), improved extensive (9%) and semi-intensive (1%) methods. Of these farms, 70% are small-scale and are mostly situated in the southwestern region. The production from extensive farms varies from 150-250 kg/ha.

Throughout the 1980s, the shrimp sector grew dramatically in response to global demand. Bangladesh produces 4.2% of the global shrimp production (Rosenberry 1996). However, over the past two years, the exportation of shrimp has declined, due mainly to disease outbreaks. In 1994-95, Bangladesh earned 1,045.64 crore Taka (US$205 million) by exporting 26,277 mt of frozen shrimp, while in 1997-98, Bangladesh exported only 18,630 mt and earned 1181.48 crore Taka (US$231.5 million).

The Expansion of Shrimp Culture

At the end of the 1960s, production of food grains in some polder areas became impossible due to stagnation of water, and people began to raise fish as an alternative. The primary species cultured were barramundi (Lates calcarifer), gold-spot mullet (Mugil parsia) and mystus (Mystus sp.). In the 1970s, the demand for, and price of, shrimp increased in the world market, and their culture became popular and profitable. Other polder areas that were not affected by stagnation also began shrimp culture in place of rice culture. Paikgacha, Dumuria, Batiaghata, Dacope, Rampal and other brackishwater areas came under shrimp culture, in addition to rice culture, and the process expanded rapidly in brackishwater areas as this subsidiary crop became increasingly popular. In the 1980s, the price of shrimp rose gradually, and as a result, expansion of shrimp culture accelerated. Influential persons and outside investors gained control of vast shrimp cultivation areas.

Socio-economic Circumstances

Earlier, people of the area depended mostly upon the cultivation of food grains. Influence and status were achieved through the possession of land and crops. However, shrimp cultivation soon produced another moneyed class; influence and social power gradually transferred to others, and the basic social hierarchy broke down. This initially created a hazardous situation in the rural areas, as the inhabitants became hostages to the whims of these people. Gradually, however, the small landowners organised. They protested against the newcomers and began individual and co-operative shrimp culture for their economic emancipation. Initially, shrimp farmers made enough profit so that farming expanded greatly within three years. In 1994, the area under shrimp cultivation reached more than 100,000/ha. Thus, co-operative and small-scale shrimp farming became very popular and profitable within a short period

Shrimp has replaced rice as the main crop; as traditional shrimp farming is easier and more profitable than rice growing. Poor womenfolk earn a considerable amount of money from fry collection, weeding out, de-heading and other related activities. Young folk with no opportunity to enter farming directly, buy small amounts of shrimp from the farms and sell them to the nearest market, providing themselve with good earnings. As well as the activities mentioned previously, there is also land preparation, fertilisation, contract-based shrimp collection etc. These seasonal activities play an important role in poverty alleviation for local landless people.

Now, the backyard of every homestead has been turned into a shallow pond where shrimp are grown. Whereas previously, many small-scale farmers had to starve through half of the year, they now have plenty of money to buy food and provisions. Even the landless in the shrimp farming areas have bank accounts and deposit money every month. The mobility of shrimp farmers has increased significantly, and shrimp farming has brought substantial changes to the livelihood status of the coastal communities in Bangladesh.

1A polder is an area encircled with an embankment to prevent the intrusion of salt water where shrimp and paddy culture are practised.

Shrimp Culture System

Aquaculture, especially shrimp culture, in the southern part of the greater Khulna area differs due to various factors, such as salinity, availability of fry and local geologic conditions. There are several types of system used in three areas:

Satkhira-Shyamnagar. Farmers in this coastal area, adjacent to the Sundarbans, are able to culture shrimp year round. The salinity is stable all year long, and fry are also available. Most farmers, therefore, get four harvests. Farmers in this area follow a more methodological approach than do those in other areas. They prepare the farm with lime, use both organic and chemical fertilisers, and even use medicines available in the market. They also try to test the water and soil, and are eager to have the assistance of the government. Their first crop is started in the first week of February and harvested in May, depending on growth. They begin to stock fry for the second time in the first week of April, and then harvest again in July. They start to stock the third crop in June and harvest in September, while the fourth crop is stocked in the first week of August and harvested in November. December and January are used for preparing the farm; they dry the ponds, plough the land, scatter lime and apply manure.

Khulna-Paikgacha. Paikgacha is an area with diverse patterns of shrimp farming. Both big farms and small farms are located here. Farmers generally grow both shrimp and rice on the same land; large farm owners lease the land for shrimp farming. In this area, the main harvest is made in June to July. However, many farmers try to have a pre-harvest and a post-harvest along with the main harvest. Farmers start to stock before the onset of winter, and the fry are conditioned to tolerate the cold. This crop will be harvested in February/March, which assists the farmers, as they obtain a good market price and have money available during what is normally a hard period. The main stocking begins in February and continues until June, depending on the availability of fry and money. The farmers like to practice staggered stocking in order to have a staggered harvest, and it continues from May to September. The last stocking is considered as a post-main harvest. Most of the farmers aim to complete harvest in August in order to leave the land for rice cultivation.

Khulna-Dacope. Farmers in this area mostly culture shrimp on a small-scale or co-operative basis. Encroaching farmers are very few; therefore, social amity and solidarity still exist. However, water management is not carried out on an equitable basis.

Bagerhat-Rampal. In this area, there is a different type of shrimp culture. None of the land is under control of polders, therefore, farmers have to prevent flooding at high tide by building strong embankments. The harvesting system is almost the same as that followed in Dacope.

Cox's Bazar. In southeastern Bangladesh, shrimp farming is a post-independence phenomenon that started off in salt beds. From December to April, crude salt is produced by evaporation, while shrimp and fish are farmed on the same land from May to November.


The information presented in this paper was generated by a qualitative survey using Participatory Rural Appraisal (PRA), a qualitative tool for in-depth assessment of people's perceptions. Discussions were also held with some key informants engaged in the production of shrimp.

PRA was conducted in three areas affected by shrimp disease. The areas included Polder-31 at Tildanga, Dacope Thana, Khulna District, where the Union Parisad Chairman, members and local elite participated. This area has suffered little shrimp disease, and here shrimp and rice are cultured at regular intervals. One session was conducted in this area, and two group discussions were also held with shrimp growers at Batbunia and Chalna. Another area chosen for PRA was in Polder 5 at Burigoalinee Union campus of Shymnagar Thana, in Sathkhira District. At least 20 shrimp producers gathered for free and frank discussions on the issues. The area has a maximum of four crops a year and suffered mass mortalities of shrimp over the past few years. Focus-group discussions were also held in Polder 16 at Kapilmuni, in Paikgacha Thana, Khulna District, where individual discussions were also held to ascertain the impact of disease.


PRA sessions, including focus-group discussions, were conducted on a number of issues relating to the impact of shrimp disease. The findings are summarised below:

Shrimp Disease

White-spot disease made its first appearance in southwestern Bangladesh in 1995. It had a high impact through 1996 and 1997, and then seemed to disappear. In 1998, there was no report of the disease. In 1997, after release into the farm, the fry were severely affected by the virus; however, the situation has since improved, and farmers reported a good harvest in 1999. Bacterial disease was noticed in some of the farms in Shyamnagar.

The diseased shrimp displayed the classic signs - red or bluish coloration and white spots under the shell. This virus affected 80% of ghers in all the polders. Dead shrimp were sometimes found on the bottom. In two to three days, mortalities reached 50-70%, and the remaining shrimp did not grow well. As a consequence, farmers harvested small-sized shrimp. Farmers also became nervous when neighbouring farms were hit with white spot, and they harvested early. Moreover, in 1998, soft-shell, swollen and cramped muscle necrosis and broken appendages appeared in cultured shrimp, problems that were attributed to different bacterial diseases.

2Ghers are modified rice fields with high, broad peripheral dikes, and are found throughout southwestern Bangladesh in areas that are seasonally or perennially inundated. A trench dug inside the dikes retains water in the dry season, while the dike protects the gher from flooding during the summer.

Causes of Shrimp Disease

Environmental and management factors relating to seasonal fluctuations in brackish water apparently influence the onset of white-spot disease. The major causes identified from the sessions were:

Poor water management

Three types of sluice gates exist: those constructed by the Bangladesh Water Development Board (BWDB), those individually constructed and those constructed by the Third Fisheries Project (TFP). Reports of virus in the individually owned and gated farms and in farms at the periphery were less. However, many farmers are located far from these gates and do not have systematic arrangements for flushing and drainage of water in the shrimp ghers. These farmers are totally dependent on the individual gate owners and need to pay them higher rent for the use of water. Although there are some sluice gates owned by the authorities, these are not serving the purpose of managing the overall water supply and drainage in the gher.

Small ghers often experience waterlogging , mainly because of under development of infrastructure. The waterlogging causes variations in the level of salinity, oxygen and natural feed. Moreover, excessive temperature increases the salinity of the stagnant water, which may produce poisonous gases such as ammonia and hydrogen sulphide and cause deterioration of the gher environment.

Lack of awareness about shrimp farming technology

Shrimp farming is a highly technical activity and very sensitive to the environment. Repeated outbreaks of viral disease in most farms have made this sector more vulnerable. Most farmers are conscious of the requirements for environmentally friendly shrimp farming; often, however, they do not fully follow these requirements, mainly because of the temptation to earn short-term profit. Most farmers adopt a "wait and see" strategy and prefer to exchange knowledge among themselves. If one farm does well from applying new knowledge, others will adopt it. Farmers are not well informed about the quality of soil and water and will apply lime and fertiliser without testing the soil. They are also not careful about using the correct stocking density. Farmers can understand when their ghers are attacked by disease, but they do not know how to deal with this problem. All this leads to adverse changes in the gher ecosystem. Decomposing faeces and other organic matter accumulate on the gher bottom, and with rising temperature, cause oxygen depletion and increases in toxic material (NH3, NO2, H2S etc.).

Imported fry

In 1994, fry were very few in local rivers, and the price increased significantly. Many small farmers failed to stock fry in time, and some stocked fry imported from Thailand. These were brought into the country without checks on their health status and without quarantine. It is generally believed that white spot syndrome virus (WSSV) was carried by these fry. Since then, many farmers have lost their harvest to this disease. In 1995, 1996 and 1997, white-spot disease spread in epidemic proportions. Some farms were affected, while adjacent farms were not. The reason for this is not known, and remedies for the disease are yet to be discovered.

3Accumulation of stagnant water due to rain or flooding that is not possible to drain and does not dry out naturally.

Intensification of Diseases

Farmers of Shyamnagar said that many of them had lost their harvest and they were very confused. The fry grew to a certain stage (50-70/kg) and then disappeared. Other species, such as crabs and fish, were also affected and disappeared within a week. The farmers tried many ways to overcome this situation, but once a farm was affected no harvest was possible. Some farmers who had earlier achieved one or two harvests could manage, while others who had been affected since the first crop had serious problems. The impact was so serious that many of them considered changing the species cultured. Reasons for losses, other than viral infection, that were identified included lack of growth, long legs, soft-shell and tail and gill rot. The occurrence of viral infection was less in Paickgacha than in Shyamnagar and was almost nil in Dacope and Rampal. The reason is assumed to be high salinity; where the salinity is less, viral infection is also less. Poor water management has increased the problem. The main constraints to production in the Paickgacha region include the high price of fry and the immaturity of shrimp. Farmers stocked both local and hatchery-raised fry, but some encountered problems of slow growth; a few had viral infections or leg lengthening. The farmers of Dacope had the problem of low growth rate; there were no reports of viral infection.

Lack of Capital

Losses due to the problems mentioned previously are harmful to the small-scale farmers and to all concerned. People carrying out this activity are not inclined to save money; they only save one term's investments and depend on the harvest. If this fails, the farmer is left with no alternative but to borrow at a high interest rate from the local moneylenders, or to get a loan from the bank, which is very difficult. Some farmers sell household belongings and invest once again, in an attempt to recover their losses. In addition to these problems, the market price of shrimp is not steady. When the harvest is at its peak, the price in the market generally falls, and farmers do not get an adequate return. Case studies of the problems disease has caused to two small-scale farmers are given in Boxes 1 and 2.

Remedial Measures Undertaken by Affected Farmers

Some farmers affected by the virus tried to overcome the problem with the help of the local Fisheries Extension Service; however, most preferred to follow the measures taken by their neighbouring farmers. Also, extension services were not always available when required. Some traders are now selling various chemicals to promote shrimp growth, and to treat bacterial infections and other problems; however, the effectiveness these compounds is not always known.

Box 1. Case study 1 - shrimp virus and Mr. Mistry.

Jatindranath Mistry, a rich farmer of Burigoalinee Village in Shyamnagar Thana, began shrimp culture when influenced by other local farmers. He had 4 ha of land, inherited from his father, near his homestead with a water supply from the sluice of the BWDB embankment. Mr. Mistry made a good earning in the early years of cultivation, and followed the traditional methods, as many others do. Being an educated and elite person, he often took advantage of advice and extension services from the local Thana Fisheries Office. He is not a saving-minded man and saved only the expenditure value of one crop.

In 1999, he started stocking his pond in the first week of February. He had applied lime, urea, TSP and cow dung during pond preparation and dried the farm and ploughed with a power tiller. Despite this, his stock became infected with white spot syndrome virus, and he lost all the shrimp. He stocked again in the first week of April, but the result was the same. During this period, he obtained a bank loan and began a third stocking; however, he again got no harvest due to viral infection. Mistry then borrowed some money locally and invested again; however, he once again had viral disease problems.

His sorrows now know no bounds. When he began aquaculture, he had his own land and did not need to borrow money for stocking. Now, the two loans hang upon him, and he has no money left to attempt further stocking. He is completely stunned and thinking that he may lease out the farm. He says that viral infection has ruined his family in all respects.


Box 2. Case study 2 - Mr. Parmal Zoarder's disaster.

During 1988, Sudhir Zoarder and his son Parimal started a shrimp farm on 5.6 ha of land belonging to them. In 1995, the farm was divided into four portions. Sudhir Zoarder got a farm of 2.5 ha, which was under two landowners. In 1996, it was again compartmentalised into two sections. Sudhir now had a farm of 1.6 ha, and handed over its management to his son Parimal. He had capital of about 200,000 Taka (US$3,900), earned earlier from shrimp fry and shrimp trading. In early February 1996, he stocked 13,000 fry at Taka 2,200 (US$43) and got a good return. In early April, he stocked 10,000 fry; however, these fry did not grow well, and thus, his return was poor, although he managed to recover his capital. He stocked again during early June, but the harvest was totally affected by viral disease. In early August, he stocked again, and again lost the entire crop to virus.

In 1997, Parimal prepared the farm and the nursery with lime, organic fertiliser, cow dung, urea and TSP. He ploughed the land with a power tiller and stocked fry costing 2000 Taka/1000 PL (US$40). All four harvests were virus free, and he had a good profit. In 1998, he stocked fry from India. He got a harvest in April; however, WSSV affected the next crops.

In 1999, during pond preparation, he applied lime, fertilisers etc., as usual, but he applied a little more TSP. Virus infected the first and second crops. Before the third crop, he dried the ponds, applied only lime, and stocked fry from Cox's Bazar; however, virus also affected the harvest. He again prepared the land and stocked, but the virus infected the shrimp again. He is now puzzled, has debts and no way left to survive. He is frustrated in every aspect, and he finds life hazardous and colourless.

Other Disease-related Issues

The following are some other impacts and issues resulting from disease outbreaks:


Participants in the PRA sessions put forward the following suggestions:


Small-scale shrimp farmers in the coastal area are presently in a poor state. The flow of capital between the shrimp farmers and related activities is reduced. Measures need to be taken to assist shrimp farmers; otherwise this potentially valuable sector will disappear from this area.


The authors acknowledge the encouragement and valuable suggestions received from Mr. Bitu D'Costa, Executive Director, and Dr. Thomas Costa, Development Director, of Caritas. Thanks are also due to Mr. Naresh C. Debnath and Mr. Ashim Kumar Pal for their untiring support in facilitating PRA sessions in the field. Mr. Ikbal Faruk deserves great credit for computer work. Lastly, acknowledgement is due to the people in the study areas for their generous contributions of time and information.


Rosenberry, R. (ed.) 1996. World Shrimp Farming 1995. Shrimp News International, San Diego, CA.

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