Previous page Top of Page Next Page


Md. Nazrul Islam

Department of Fisheries
Matsya Bhaban, Shaheed Capt. Mansur Ali Saroni
Ramna, Dhaka, Bangladesh

Islam, M.N. 2002. Extension methodologies for aquatic animal health management in rural pond culture - lessons from Bangladesh. p. 287-296. 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.


Bangladesh has a long history of rural, small-scale aquaculture, most of it carp culture, either traditional, improved traditional or polyculture, although other species are cultured in both monoculture and polyculture. Freshwater prawn farming, integrated with rice cultivation and certain fish species, is also practised. Disease problems are occasionally observed, and these are mainly attributed to poor husbandry. However, a serious outbreak of epizootic ulcerative syndrome (EUS) occurred in 1998, and viral infections of marine shrimp occurred in 1994 and 1996. These outbreaks served to highlight the importance of aquatic animal health management in Bangladesh. Intensification of traditional aquaculture systems, promoted by many extension projects, is considered to be the cause of many of the problems encountered. This paper describes ongoing aquaculture extension projects and the role of the government extension services in the provision of fish health management.


In Bangladesh, homestead pond-fish culture is an age-old traditional practice of the rural people. Most rural fish farmers practice traditional, improved traditional or carp polyculture using major carps, common carp and Chinese carps. A variety of other species including silver barb, catfishes and tilapias are also used in polyculture and monoculture systems. Increasing numbers of relatively advanced and experienced farmers have adopted the semi-intensive culture systems introduced by various projects. Although the number of intensive pond-culture systems is small, a number of small-scale commercial farmers are now in business. Nowadays, freshwater prawn farming is well integrated with paddy production and the culture of certain fish species. Due to the low intensity of culture practices carried out by the majority of farmers in rural ponds, only occasional disease problems are observed, which are mainly attributed to poor husbandry.

There was a serious outbreak of epizootic ulcerative syndrome (EUS) in freshwater fish in 1988 and outbreaks of viral disease in 1994 and 1996 in the coastal shrimp farms, highlighting the importance of aquatic animal health management in the country. Intensification of culture systems, involving such practices as increased stocking rates, increased feeding and fertilisation programmes, which sometimes result in nutrient accumulation, algal blooms, dissolved oxygen deficiency and other water quality problems, caused disease problems in ponds in rural areas (Kumar 1992). As a result of degraded water quality and environmental problems in rural pond culture, occurrences of infectious disease are encountered, and their prevention and control are considered by the aquaculture extension services to be important.


In Bangladesh during the ten years from 1987 to 1997, total fish production increased from 0.83 million mt to 1.3 million mt, while aquaculture production increased from 176,000 to 432,000 mt, which was mainly due to the impact of project-based aquaculture development and extension services in the rural areas. In Bangladesh, there are over 1.3 million ponds, covering an estimated area of 0.147 million ha, some 6,000 ha of ox-bow lakes and 0.5 to 0.7 million ha of non-conventional, semi-closed and seasonal waters in the form of roadside ditches, borrow pits and irrigation canals. There are also 0.114 million ha of natural depressions and 0.143 million ha of coastal polders suitable for aquaculture. A programme has been undertaken to bring perennial and seasonal water bodies under the aquaculture extension programme during the current Fifth Five Year Plan (1997-2002), in order to increase the present total production of fish from 432,000 to 628,000 mt.

The extension service of the Department of Fisheries (DOF) has been weak since its inception. In 1983, the department was reorganised, creating one professional Thana Fisheries Officer and two technical support staff in each thana1, providing fish-culture extension services throughout the country. A large number of foreign-funded aquaculture development and extension projects were implemented by the DOF during the last ten years. Aquaculture infrastructure facilities, fish and shrimp hatcheries, fish seed multiplication farms, training and demonstration farms and aquaculture training centres were developed in the public sector through these projects. Infrastructure developed through these extension projects is presently used to provide extension support services to the rural fish farmers. Different donor-aided aquaculture development projects have been implemented with strong fish-culture extension components, with different approaches and methodologies, and for different target groups of farmers. Aquaculture extension programmes may be categorised by taking into consideration pond-fish culture technology packages, the target group of farmers, fish-culture training demonstration and awareness methods, demonstration farm operating cost sharing, cost effectiveness and replicability. The important project-based extension approaches and methods are as follows:

Second Aquaculture Development Project

The Asian Development Bank (ADB)-assisted Second Aquaculture Development Project focused on semi-intensive carp polyculture in 21 districts of the country for all categories of farmers (Bhuiyan et al. 1996). The staff of the DOF, working in the selected districts and thanas, was trained to organise demonstrations of improved fish-culture techniques. The extension teams worked with the farmers to implement improved pond management, following the principles of good fish husbandry. The project provided production inputs to the participating fish farmers in exchange for their agreement to follow the improved pond production strategy and to allow neighbouring farmers to visit and observe improved farming activities; the cost of inputs was recovered during harvest. There was a programme for provision of credit to commercial fish farmers; however, the disbursement and recovery rate of the credit scheme was not satisfactory. The cost of extension services was high in respect to their sustainability. As the government could not provide a budget after completion of the development activities, the extension activities of the project were discontinued.

1A thana is an administrative unit equivalent to a sub-district.

Mymensingh Aquaculture Extension Project (MAEP)

The Danish International Development Agency (DANIDA)-assisted Mymensingh Aquaculture Extension Project has developed individual farmer training through intensive supervision suitable for poor rural fish farmers. Poor fish farmers in the project area have been organised and trained by project personnel (MAEP 1996). A micro-credit scheme has been introduced in co-operation with a commercial bank and a non-governmental organisation (NGO) in the project area. The experience of this project was extended in adjacent districts and replicated in greater Noakhali and Potuakhali districts, with some modification of extension approaches (i.e., individual farmer training to group training approach). The cost of this intensive extension approach appeared to be very high in respect to its sustainability, and the government was unable to provide budget for continuation after its completion.

North-West Fisheries Extension Project

The Department for International Development (DFID)-assisted North-West Fisheries Extension Project was formulated to develop a fish hatchery and training centre at Parbatipur during its first phase. During the second phase, the project provided training and extension services to fish farmers of the greater districts of Dinajpur and Rangpur through the extension personnel of the DOF and a local NGO micro-credit programme, using model-village extension approaches (Islam and Faruk 1996). Extension personnel identified villages with fish culture potential and organised interested fish farmers into groups. The project provided technical services for fish culture, and the NGOs provided the required operational funding for pond-culture inputs. This extension approach seems to be successful, and costs were moderate in respect to its sustainability. This approach will be replicated in 200 thanas under the International Development Assistance (IDA)-assisted Fourth Fisheries Project.

Ongoing Aquaculture Extension Projects

During the Fifth Five Year Plan (1997-2002), 23 Aquaculture Development and Extension Projects have been undertaken. In most of the projects, aquaculture training and extension are considered as major activities. A list of aquaculture extension projects with investment cost, location, number of farmers, expected output and source of funding, is shown in Table 1. The bilateral donor-assisted projects funded by DANIDA and DFID focused on food security, poverty alleviation and income generating activities of rural farmers, whereas, multinational donor (IDA, International Fund for Agricultural Development (IFAD))-assisted projects are mainly for infrastructural/institutional development to increase overall fish production. The Government of Bangladesh (GOB)-funded projects focused on appropriate aquaculture technology and cost effectiveness for all categories of rural fish farmers. It is estimated that nearly 500,000 farmers in rural areas are being provided with technical assistance and extension services, and incidental to this support, about 300,000 mt of fish will be produced by the farmers.

Table 1. On-going aquaculture extension projects (source: Department of Fisheries).


Rural Pond-fish Culture Extension

The technical assistance projects Institutional Strengthening in the Fisheries Sector (UNDP/FAO/BGD/87/045) and Strengthening of Rural Pond Fish Culture Extension Service (FAO/TCP/BGD/4451/T) developed an appropriate aquaculture extension service for all categories of small-scale rural fish farmers called the "Trickle Down Aquaculture Extension Approach." The ideology of this approach was the development of self-reliance and awareness in the minds of fish farmers by repeated training, demonstration, and close supervision by field-level extension personnel. This system of extension activity provided farmer-to-farmer extension through small groups, each consisting of one result demonstrator fish farmer and five fellow fish farmers. Farmers with access to ponds and ability to invest operating costs for fish culture were the target group of these projects. This programme did not require cash or input assistance for the farmers. It was observed that farmer-to-farmer extension services in a small group had many advantages for sustainability. The resulting demonstrator fish farmers under the two technical assistance projects achieved an average production of 3,539 kg/ha and 4,105 kg/ha, respectively.

Thana Level Aquaculture Extension Services

In light of the experience of the UNDP/FAO/BGD/87/045 and FAO/TCP/BGD/ 4451/T projects, the "Thana Level Aquaculture Extension Services," which covers 400 thanas in 59 districts, was formulated with government funding. An annual work plan and implementation matrix have been drawn up, with six groups consisting of a total of 36 fish farmers (one result demonstrator and five fellow farmers) during the first three years (1995-96 to 1997-98), and nine groups consisting of a total of 54 fish farmers during the last two years (1997-98 to 1999-2000). Implementation over this period in each thana will result in the training of 79,200 rural fish farmers in improved methods of fish culture. This project will create an opportunity to enhance average annual fish production at the rate of 3.5 mt/ha in the ponds of result demonstrators and 2.5 mt/ha in the ponds of fellow farmers groups. At the end of the project period, total fish production enhancement would be 31,780 mt. In addition, 79,200 trained farmers will have part or full-time job opportunities as a result of project extension activities. Analysis of fish production data for the last three years of the project (1995-96 to 1997-98) indicates that an average production of 3,070 kg/ha has been achieved by the result demonstrator fish farmers, and 2,342 kg/ha has been achieved by the fellow fish farmers during 1997-98 (Table 2). It was observed that the result demonstrator and fellow fish farmers achieved 78% and 86% of the targeted fish production, respectively (Islam and Moniruzzaman 1999). The essence of the project is that its benefits will not stop at the end of the project. Fish-culture extension services will continue as a regular activity of the DOF. By this means, all ponds in each thana will be utilised for fish culture using improved and appropriate technologies. An extension channel to send any useful aquaculture package to the field has already been established using this network of contact farmers (result demonstrator fish farmers and fellow fish farmers).

Table. 2. Fish production of farmers under the Thana Level Aquaculture Extension Project.

Aquaculture Technology Packages

Several aquaculture technology packages have been developed and employed in rural pond culture through different extension approaches, although not all of them have faired equally well. The culture systems include: a) carp polyculture, b) raising fry and fingerlings of carps, c) freshwater prawn with carp polyculture, d) integrated fish cum duck/chicken farming, e) integrated rice cum fish farming, f) culture of silver barb, g) culture of pungas, and h) culture of tilapias. Among these technology packages, carp polyculture is considered the most appropriate technology for extension to small-scale rural pond culture (Islam and Moniruzzaman 1999).


Under different projects, various aquaculture intensification approaches, such as increased stocking rates, and increased feeding and fertilisation programmes, have sometimes resulted in nutrient accumulation, frequent appearance of algal blooms, dissolved oxygen deficiency and other water quality problems in undrainable ponds, causing occasional disease outbreaks. Consequent to this, risk prevention and control of diseases are considered important by the aquaculture extension services of the country. Providing a fish disease diagnosis and treatment service is difficult with the existing extension set up of the DOF and with the limited husbandry knowledge of rural fish farmers. Aquaculture extension implementation manuals, pond-fish culture manuals, fish health management manuals and water analysis kits have been supplied to all the extension personnel of the DOF. Farmers have also been trained to use these manuals and kits.

General Causes of Fish Health Hazards

The extension project identified the following general hazards to fish health in rural pond culture:

Fish Health Hazard Preventive Measures

The extension project identified the following preventive measures for fish disease in rural pond-culture systems (BAFRU 1996, Islam and Moniruzzaman 1998):

Pre-stocking measures

Stocking measures

Post-stocking measures

Recommended Physico-chemical Conditions of Pond Water

All extension officers are provided with water analysis kits and pond fish culture equipment to provide farmers with technical support to analyse the physico-chemical conditions of pond water (Kumar 1992). The optimum parameters are given in Table 3.

Table 3. Optimum levels for physic-chemical parameters in pond water (from Kumar 1992).

Among these parameters, turbidity, dissolved oxygen, pH and alkalinity are considered the most important.

Common Chemicals and Drugs for Fish Disease Control

Extension officers and their technical support staff have received training on basic diagnostic methods for the common fish diseases of rural pond culture, as well as on fundamental disease control measures (Chinabut et al. 1993, Ahmed and Kumar 1993). Common treatment methods are given in Table 4.

Table 4. Common treatment methods for aquatic animal diseases.

Some chemicals are applicable for dip or bath treatment, while others are applicable for pond treatment. However, due to cost considerations, dose calculation and also, method of application, only limited measures can be taken up by small-scale farmers. Among these treatment measures, liming, dipterex, malathion/sumithion, potassium permanganate and sodium chloride treatment are most important.


Problems and Constraints

A number of diverse and complex problems confront aquaculture extension services directed towards fish health management in rural pond culture. Some of these are listed below:

Issues and Recommendations


Ahmed, A.T.A., and D. Kumar. 1993. Prevention and Treatment of Fish Diseases. Department of Fisheries, FAO/UNDP-BGF/87/045 Institutional Strengthening in the Fisheries Sector, 20 p.

BAFRU. 1996. Technical Manual of Pond Production Biology. Department of Fisheries, 58 p.

Bhuiyan, A.K.A., N. Ahmed and M.R. Islam. 1996. Carp Polyculture in Pond. Second Aquaculture Development Project, Department of Fisheries, 25 p.

Chinabut, S., K. Tonguthai, H. Rodger, P. Chanratchakool and R. Wootten. 1993. Fish Health Training Course Module. BAFRU, 61 p.

Islam, A.Z.M.N., and G. Faruk. 1996. Simple Fish Culture Methods. North West Aquaculture Extension Project, Department of Fisheries, Parbatipur, Dinajpur, 80 p.

Islam, M.N., and M. Moniruzzaman. 1998. Carp Polyculture Management, Thana Level Aquaculture Extension Project, Department of Fisheries, 57 p.

Islam, M.N., and M. Moniruzzaman. 1999. Effect of thana level extension services on fish production. Fisheries Resources Development-A, Fish Week` 99, Department of Fisheries, p. 26-30.

Kumar, D. 1992. Fish Culture in Undrainable Ponds - a Manual for Extension. FAO Fish. Tech. Pap. 325, 239 p.

Mymensingh Aquaculture Extension Project (MAEP). 1996. Carp Polyculture. Department of Fisheries.

Previous page Top of Page Next Page