Previous page Top of Page Next Page


David Brown and Alan Brooks

Fisheries Training and Extension Project, Phase 2 (FTEP-II)
8th Floor, Matsya Bhaban,
Shaheed Capt. Mansur Ali Saroni,
Ramna, Dhaka,

Brown, D., and A. Brooks. 2002. A survey of disease impact and awareness in pond aquaculture in Bangladesh, the Fisheries and Training Extension Project - Phase II. p. 85-93. 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.


A survey of the importance of fish disease to 257 farmers from six districts in Bangladesh was carried out during September 1999. The farmers interviewed were selected from a general baseline study of 2,500 farmers who were about to undergo training with the Fisheries Training and Extension Project - Phase II (FTEP-II). FTEP-II is a bilateral aid project between the governments of the United Kingdom (Department for International Development, DFID) and the Department of Fisheries (DoF) of the Government of Bangladesh. The primary stakeholders of the FTEP-II project are poor and carry out "low input, carp polyculture."

The interviewed farmers were capable of identifying, at most, nine major causes of fish death in their ponds. The most common causes of death were a "red spot" disease referred to as EUS (epizootic ulcerative syndrome), "fin/gill rot," "air gulping" and "cotton fungus." No laboratory diagnosis of these diseases was possible. In terms of constraints to production, the majority of farmers did not think that fish disease was important. Rather, they identified issues such as "lack of personal knowledge of fish pond management," "credit and financial problems" and "fry/fingerling supply" as being more important.

The effect of fish disease on the farmers' ponds and livelihoods was limited. Fish seldom died off all at once, and 47% of farmers were able to either eat or sell the dead fish. Most farmers turned to other farmers for advice when disease occurred in their ponds but had a limited range of treatments, with potassium permanganate being the most popular (although most farmers simply harvested all the fish). In terms of financial loss, only 4% of the farmers said fish disease losses were "big and unacceptable." Average Losses were estimated as 3% of total "on-farm" income, and equal to around US$31 per year.

Although fish mortality is clearly a problem for a few farmers (<6%) who experience complete loss of a crop, for the majority, the usual pattern of loss was a few fish weekly, and these were either consumed, sold or thrown away. This pattern would be expected in such systems with low stocking densities. Farmers ranked their own lack of knowledge about fish culture and credit as the main factors limiting production (above disease). Consequently, for these farmers, the FTEP-II project focuses it's extension messages on better pond management techniques such as green water management, stocking and pond preparation, with fish disease issues discussed during sessions dealing with risks.


The Fisheries Training and Extension Project Phase-II (FTEP-II) is a bilateral aid project between the governments of the United Kingdom (Department for International Development, DFID) and Bangladesh (Department of Fisheries, DoF). The goal of the project is to increase sustainable aquaculture production by poor farmers in Bangladesh through building the capacity of the DoF to deliver, directly and/or indirectly, appropriate support to them. In particular, FTEP-II helps develop skills in training of trainers and the delivery of basic pond aquaculture techniques. A wide range of additional project activities are undertaken, such as the development of training and extension networks; training of nongovernmental organisations (NGOs), school and bank staff; and newsletters.

The principal beneficiaries of the FTEP-II project are poor fishfarmers, and the project targets 108,000 farmers who will take part in training in basic carp polyculture. Of these, 40% must have less then 0.5 acres of fishpond area, 20% must have less than 0.5 acres of crop land and 10% must have less than US$400 (20,000 Bangladesh Taka) per year total household income. The project aims to improve the livelhoods of these target beneficiaries through increasing fish production from 49 to 146 gm/m2 for seasonal ponds and from 146 to 245 gm/m2 for perennial ponds. It is predicted that at least 30% of these farmers will adopt the guidelines given for better fish culture.

The FTEP-II project adopts a "demand led" approach to extension and responds directly to the needs of farmers. With the exception of outbreaks of diseases such as epizootic ulcerative syndrome (EUS), the project beneficiaries do not consider disease to be a serious risk to their aquaculture activities. Because of this demand-led approach, the project, therefore, does not prioritise training in disease management for these farmers, rather it is dealt with during discussions on risks and hazards in aquaculture.


The results presented herein are from a field survey of 257 farmers from six districts in Bangladesh (Rajbari, Madaripur, Bogra, Lakshimpur, Feni and Comilla). The survey was carried out by the FTEP-II project "field enumerators" between August and September 1999. This survey was carried out as part of the routine socio-economic "baseline survey" of farmers who had been selected to take part in training.

In all cases, only the one main pond owned by the farmer was used for calculation of stocking densities, production etc.


Socio-economic Profile of the Surveyed Farmers

Gender, family and education

The majority of farmers interviewed were male (93%), with an average age of 36 years and a family size of seven. Most male farmers are educated to secondary school level and considered themselves to work in agriculture. The female respondents interviewed considered themselves to be housewives and were mainly educated to primary school level (Table 1).

Table 1. Gender, age education and occupation of interviewed farmers.

Land and pond ownership

The average total land holding of the male farmers interviewed was more than double that of the female farmers (21,680 m2 and 8,160 m2, respectively) (Table 2). However, the pond area of male farmers was only 1.5 times that of female farmers.

Table 2. Average land/pond area (m2) of respondent farmers.

Sources of income

As is typical in Bangladesh, the household income of respondents was found to be derived from a wide variety of sources, with 76% reporting that their main income came from between two and four sources. The most frequently reported sources of income for these farmers were fish production, rice (and other field crops), small business enterprise (such as rickshaw pulling), fruit and vegetable production and significantly, full time work (Table 3). Fish production contributed 9% of the total cash household income per year, excluding the notional value of fish which were consumed by the household. On average, the most important sources of income were field crops sales, small business enterprise and full time work.

Table 3. Sources of income for respondent farmers.

Aquaculture Practices

The production methods of the respondents can be summarised as "improved, low-input carp polyculture." Farmers stock regularly and occasionally use feed and fertiliser. The majority of the ponds were individually owned and managed by the interviewee (55%). Flood affected only 3% of the ponds, and 17% were classed as seasonal. The average pond area was 1,093 m2.

Ponds of this size in Bangladesh have many (and sometimes competing) uses in addition to fish production. For example, over 60% of respondents reported that their ponds had at least three important uses. These were fish production (99%), bathing (household, 88%) and domestic use (cooking/cleaning, 77%). Other uses reported were bathing cattle (10%), drinking for cattle (13%) and crop irrigation (5%). These ponds should therefore be looked on as an important part of the total household and only seldom drained for cleaning or removal of silt.

Before production (and without training), few farmers used either lime or fertiliser (Table 4). The main inorganic fertiliser was cow dung, with only very few (2%) using poultry manure.

Table 4. Main pre-stocking inputs of surveyed farmers.

Planned stocking was carried out by 98% of farmers during April. May and June, with up to 16 different species used. However, the majority of farmers (75%) used between three and five species, which included "rui" (Labeo rohita), "catla" (Catla catla), "mrigal" (Cirrhinus cirrhosus), "silver carp" (Hypophthalmichthys molitrix) and "carpio" (Cyprinus carpio). Most farmers (52%) could choose where they bought fry and commonly bought from different sources. For example, 64% of all farmers purchased from fry traders, 41% from private hatcheries, 27% collected from the wild and 24% purchased from government hatcheries. When asked to express a preference for the source of fry, 25% of farmers stated that "wild caught" was best, with only 12% opting for traders, 13% for private hatcheries and 17% for government hatcheries; the remainder expressed no preference. On the whole, most farmers (56%) were happy with the quality of the fry they purchased.

After stocking, not only did the number of farmers reporting that they applied fertiliser increase significantly, but so too did the application rates (Table 5). However, the application of lime after stocking was lower than before stocking, with both reduced frequency of use and dosing rates. The majority of farmers used supplemental feeds after stocking. The four most favoured feeds were oil cake, rice bran and wheat bran, whilst duckweed was used by only 3% of farmers.

All farmers consumed fish from their ponds during the production cycle. On average, 17% of the harvest was consumed, but this ranged from 0.5% to 100% per year. Average production was 64gm/m2. If farmers carried out a final harvest, it took place during December and January.

Table 5. Main post-stocking inputs of surveyed farmers.

Results of the Fish Health Survey

When asked about disease occurrence and mortalities in their fishponds, farmers were allowed to express their observations in their own words. Although the names for these diseases and abnormalities have been translated into English, some of them probably do not represent true cases of "clinical" disease.

Occurrence of disease and mortalities

When asked whether the farmers had problems with fish dying of whatever cause (including disease), 6% reported that they had problems during that production cycle and 42% reported that they had problems during the last year. This apparent discrepancy was due to the timing of this survey, as farmers were only at the start of their current cycle and disease problems were yet to manifest themselves. Only 21% of the farmers could recall having disease problems more then two years ago. Significantly, 31% of farmers reported that they had never had problems with fish death/disease.

Of the farmers that reported mortalities or disease in their ponds, most were able to describe the common characteristics of a wide range of conditions resulting in fish death (Table 6). However, without proper laboratory diagnosis, it is clearly not possible to say with certainty that the terms that they used are accurate.

The most commonly reported conditions were "red spot/EUS" (78%), "fin/gill rot" (46%) "gulping for air" (30%) and "cotton fungus" (20%) (Table 6). Red spot/EUS as the most common disease was confirmed by the opinion of farmers, with 52% feeling that it was the most often seen disease in their ponds. Of these diseases, morphological and behaviourial abnormalities, some are almost certainly linked to poor pond management. For example, "gulping" is likely to be due to water quality problems resulting in low dissolved oxygen (DO) levels whilst "big head" may be due to insufficient feeding/fertilisation. Poisoning refers to killing of ponds by jealous neighbours and is a common problem for successful fish farmers in Bangladesh.

Table 6. Frequency of diseases causing fish death reported in farmers' ponds.

Once disease was present in their ponds, farmers reported that fish seldom died off all at once. Only "whirling" (5.3% of farmers), gulping (3.8%), cotton fungus (2.9%), fin/gill rot (2.5%) and red spot (1.6%) caused complete pond die off. This is not surprising considering the low intensity of production. Most commonly, a few fish died on a daily or weekly basis (Table 7). Some of the diseases caused more frequent weekly losses than daily losses, such as bighead, red spot, cotton fungus and gulping. Only whirling and parasites caused significantly more frequent daily than weekly losses.

With such sustained frequent losses, it is not surprising that 47% of farmers utilised the dead/diseased fish. Overall, 17% reported that they consumed them, whilst 22% were able to sell all the dead fish. Only 8% both sold and ate the dead fish. Surprisingly, 44% of farmers reported that they threw away all the fish that died from disease. A minority (9%) left the fish in the ponds.

Table 7. Pattern of fish death due to diseases.

Treatments and advice for fish disease

When asked whom they turned to for advice when they had fish disease problems, most farmers (55%) indicated that they went to other farmers. However, a significant number went to government officers (Assistant Fishery Officer, 15%; Upazilla Fisheries Officer, 13%) and fry traders (12%). The remainder (5%) turned to other sources, including NGOs, medical doctors, television, hatcheries and textbooks. The majority of the farmers (60%) said they trusted only their own judgement with the advice, and 62% considered the advice they received to have been useful.

Farmers reported relatively little scope in terms of options for treatment of diseased fish. Most farmers (52%) used potassium permanganate (KMNO4) as a treatment, whilst lime was used by 40% of farmers and salt by 11%. Nearly half the farmers (47%) harvested the pond when they had disease problems. The remaining farmers (0.6%) used a variety of other treatments, such as disinfectants (Savlon, Dettol), banana leaves, fertiliser, alum and water exchange. Of the farmers expressing an opinion about the treatments, potassium permanganate was considered by 32% of farmers as the best treatment, whilst 26% felt harvesting was best.

Half of the farmers reported that they obtained these treatments from other farmers, whilst fry traders, shops and the DoF supplied the remaining 9%, 3% and 10%, respectively. A minority of the remaining farmers (11%) made their own treatments, and 17% sourced from elsewhere (hatcheries, NGOs).

In terms of treatment efficacy, only 21% of farmers reported success, while 49% reported partial success and 11% reported failure.

Importance of fish disease to farmers

Farmers were asked to rank the technical importance of fish disease during production by marking which other issues were clearly more important (Table 8) (these issues were described by the farmers as important constraints on production during group meetings).

Table 8. Ranked frequency of farmers responding "yes" to whether the subject is "more important than fish disease."

Farmers therefore perceived that their own lack of knowledge and investment/credit problems were more important constraints to production than disease. Fry supply problems (quality and quantity) were seen by farmers as of equal importance to disease.

When asked whether the loss of money or food was more or less important when fish died due to disease, 20% of the farmers responded that the loss of food was more important, 17% said that the monetary loss was more important and 56% said that they were of equal importance (7% had no opinion).

Farmers were also asked to rank the general loss they had due to fish disease. Twenty percent felt that it was of no importance, 34% felt it was minor, 22% felt that it was moderate but acceptable, 19% felt it was big but acceptable, and 4% felt it was big and unacceptable.

The average "on-farm" income for respondents was US$1,017 per year. Losses due to fish disease made up, on average, 3% of this total on-farm income (US$31), which corresponded to 18.5% of the total average yearly income from fish production.


Most of the farmers interviewed in this survey can be considered as poor and operate "low-input" carp polyculture production systems. Most farmers stock, lime and fertilise ponds at some point during production, and many use supplemental feeds. Significantly, when considering the impact of disease on these farmers, most consume a considerable amount of fish they produce.

Although unable to describe the detailed clinical signs of diseases, a significant number of farmers reported death of fish from a number of causes. The most frequently reported were called, in Bangladeshi, "red spot/EUS." gill/fin rot, air gulping and cotton fungus.

For affected farms, losses to disease were not significant in terms of money or food, and most farmers either simply sold or ate the dead fish. Very few farmers reported a total loss of their crop, and this was not surprising considering the low-intensity, low-risk systems they operate. Of those that had experienced a loss, only a minority (4.2%) felt that it was unacceptably large. In financial terms, the losses were also small, relating on average to only 3% of total "on-farm income."

In the farmers' opinion, it was their lack of understanding of fish culture and their inability to access credit that were the main constraints to their fish production. It is likely that once farmers have a better understanding of low-input carp polyculture methods, the likelihood of diseases occurring and their impacts will be reduced. However, should these farmers intensify their production the incidence and impact of fish diseases will increase.

For extension service providers, the key message from this survey is that farmers are interested in better basic training in aquaculture, rather than specific information regarding fish diseases. Key routes for information dissemination could be directly through extension agents, but because farmers generally go to other farmers for information, the use of indirect farmer-farmer extension approaches would be effective in this case.

Previous page Top of Page Next Page