Freshwater prawn farming in Bangladesh: history, present status and future prospects Nesar Ahmed 1 , Harvey Demaine 2 & James F Muir 3 1 Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh 2 Regional Fisheries and Livestock Development Component, DANIDA, Noakhali, Bangladesh 3 Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland, UK Correspondence: N Ahmed, Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh. E-mail: [email protected]Abstract Within the overall agro-based economy in Bangla- desh, freshwater prawn ( Macrobrachium rosenbergii ) farming is currently one of the most important sec- tors of the national economy. During the last two dec- ades, its development has attracted considerable attention for its export potential. Freshwater prawn farming o¡ers diverse livelihood opportunities for a large number of rural poor. Although the prospects for prawn farming are positive, it requires some research and development activities for long-term sustainability. This paper provides an overview of freshwater prawn farming in Bangladesh. Keywords: freshwater prawn, Macrobrachium rosenbergii , Bangladesh Introduction Bangladesh is considered one of the most suitable countries in the world for giant freshwater prawn ( Macrobrachium rosenbergii De Man 1879) farming, because of its favorable resources and agro-climatic conditions. A sub-tropical climate and a vast area of water bodies provide a unique opportunity for the production of Macrobrachium spp. Twenty-four spe- cies of freshwater prawns including 10 species of Macrobrachium are found in Bangladesh (Table 1). However, only M. rosenbergii has signi¢cant aquacul- ture potential and is commercially cultured (Akand & Hasan 1992; Ahmed 2001; Muir 2003a). Freshwater prawn ( M. rosenbergii ) farming is cur- rently one of the most important sectors of the national economy and during the last two decades, its development has attracted considerable attention because of its export potential. The prawn and shrimp sector as a whole is the second largest export industry after readymade garments, generating US$380 million annually and 5.6% of the total value of exports [Department of Fisheries (DOF) 2006]. There are 1.2 million people employed in prawn and shrimp production and a further 4.8 million house- hold members are associated with the sector (USAID 2006). Unfortunately the export value and the num- ber of people involved in prawn farming is not known because statistics often do not distinguish between prawn and shrimp. Despite the growth of this sector, a number of is- sues are important for freshwater prawn farming in Bangladesh including production technology, socio- economic and environmental aspects ^ all of these are important parameters of sustainability. This pa- per reviews the emergence and recent development and future prospects of M. rosenbergii farming in Bangladesh. The aim of this paper is to highlight key issues determine sustainable prawn farming to meet the international market, environmental and social challenges. History of development History In Bangladesh, freshwater prawn farming ¢rst started in the southwest region in the early 1970s (Mazid 1994). After the independence in 1971, locals learnt to catch prawn fry from people on the other Aquaculture Research, 2008, 1^14 doi: 10.1111/j.1365-2109.2008.01931.x r 2008 The Authors Journal Compilation r 2008 Blackwell Publishing Ltd 1
Transcript
Freshwater prawn farming in Bangladesh: history,
present status and future prospects
NesarAhmed1, Harvey Demaine2 & James F Muir3
1Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh2Regional Fisheries and Livestock Development Component, DANIDA, Noakhali, Bangladesh3Institute of Aquaculture, University of Stirling, Stirling FK94LA, Scotland, UK
Correspondence: NAhmed, Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh-2202,
Within the overall agro-based economy in Bangla-desh, freshwater prawn (Macrobrachium rosenbergii)farming is currently one of the most important sec-tors of the national economy. During the last two dec-ades, its development has attracted considerableattention for its export potential. Freshwater prawnfarming o¡ers diverse livelihood opportunities for alarge number of rural poor. Although the prospectsfor prawn farming are positive, it requires someresearch and development activities for long-termsustainability. This paper provides an overview offreshwater prawn farming in Bangladesh.
Bangladesh is considered one of the most suitablecountries in the world for giant freshwater prawn(Macrobrachium rosenbergii De Man 1879) farming,because of its favorable resources and agro-climaticconditions. A sub-tropical climate and a vast area ofwater bodies provide a unique opportunity for theproduction of Macrobrachium spp. Twenty-four spe-cies of freshwater prawns including 10 species ofMacrobrachium are found in Bangladesh (Table 1).However, onlyM. rosenbergii has signi¢cant aquacul-ture potential and is commerciallycultured (Akand &Hasan1992; Ahmed 2001; Muir 2003a).Freshwater prawn (M. rosenbergii) farming is cur-
rently one of the most important sectors of the
national economy and during the last two decades,its development has attracted considerable attentionbecause of its export potential. The prawn andshrimp sector as awhole is the second largest exportindustry after readymade garments, generatingUS$380 million annually and 5.6% of the total valueof exports [Department of Fisheries (DOF) 2006].There are 1.2 million people employed in prawn andshrimp production and a further 4.8 million house-hold members are associated with the sector (USAID2006). Unfortunately the export value and the num-ber of people involved in prawn farming is not knownbecause statistics often do not distinguish betweenprawn and shrimp.Despite the growth of this sector, a number of is-
sues are important for freshwater prawn farming inBangladesh including production technology, socio-economic and environmental aspects ^ all of theseare important parameters of sustainability. This pa-per reviews the emergence and recent developmentand future prospects of M. rosenbergii farming inBangladesh. The aim of this paper is to highlight keyissues determine sustainable prawn farming to meetthe international market, environmental and socialchallenges.
History of development
History
In Bangladesh, freshwater prawn farming ¢rststarted in the southwest region in the early 1970s(Mazid 1994). After the independence in 1971, localslearnt to catch prawn fry from people on the other
r 2008 TheAuthorsJournal Compilationr 2008 Blackwell Publishing Ltd 1
side of the Ichamati River, on the border betweenBangladesh and India, at Debhata in the Satkhira dis-trict (BOBP1990). It was Hormuz Ali who introducedthe technique of wild prawn fry collection.Around 1978, a few well-o¡ local farmers in the
Fakirhat area of Bagerhat district (Fig. 1) began toexperiment with stocking prawn postlarvae in carpponds. These innovators experimented with con-struction design, feeding, stocking and other techni-cal aspects and pro¢ted well (Kendrick1994). Finallya few pioneers, some time between the late1970s andthe mid 1980s, developed the ¢rst prawn cultivationin rice ¢elds in low lying agricultural land.The namemost frequently raised as the ‘father of freshwaterprawn farming’ is Keramat Ali of the Fakirhat areain Bagerhat district (Rutherford1994).In the late1980s, this farming practice began to be
adopted widely in the original location in the Fakir-hat area, where prawns were grownalongwith carpsand rice (Kamp & Brand1994). By around1987, a fewlocal farmers ¢rst converted their low lying lands andrice ¢elds into gher (prawn farms are locally knownas gher) for prawn cultivation (Kendrick 1994). Sincethen the pace of adoption increased dramatically asmore farmers watched their neighbors pro¢ting fromprawn cultivation and decided to begin prawn farm-ing as well (Rutherford 1994). The news soon spreadto other areas, and farmers in other parts of Bagerhatdistrict began to adopt this new technology.Although it has developed strongly in other areas,the number of prawn farms and farmers are still thehighest in the Fakirhat area. Potential returns forprawn farming are good and farmers have been at-tracted by its potential as an income earner. For thepeople of Fakirhat, proudly called ‘the Kuwait of Ban-gladesh’, prawn production was reported to haveincreased subsistence farmers’ incomes considerably(Kendrick1994).
The early innovators tended to be large andmiddlesize farmers, but increasing numbers of small andmarginal farmers also started prawn farming(Rutherford 1994). The expansion of prawn cultiva-tion has been dramatic, and since1990 adoption hasaccelerated, spreading to other southwest districtssuch as Khulna and Satkhira (Fig. 1). Since the early1990s prawn farming has become one of the ¢nan-cially most attractive investment opportunities inthese areas (Ahmed 2001). In recent years (since2000) the increase in demand for prawn in the inter-national market has attracted many ¢sh farmers toprawn cultivation in di¡erent parts of Bangladesh.As a result, prawn farming has also developed insouthern Bangladesh, mainly Noakhali and Patua-khali districts and north-central Bangladesh, mainlyMymensingh district (Asaduzzaman, Wahab, Yi,Diana & Lin 2007).
Institutional role
Freshwater prawn cultivation practice has developedas an indigenous technology, with no planningand little support or assistance from any outsidesources, including the government (Kamp & Brand1994). The DOF and non-government organizations(NGOs) were slow to respond to the opportunitiesof the sector (Rutherford 1994). However, somedonor-funded projects have shown interest in pro-moting prawn culture, for example, the CARE-sup-ported Greater Options for Local Developmentthrough Aquaculture (GOLDA) project, GreaterNoakhali Aquaculture Extension Project (GNAEP)and theAgro-based industries andTechnology Devel-opment Project (ATDP). Recently the WorldFishCenter and Winrock International have becomeactive in the sector.
Table 1 Macrobrachium species in Bangladesh
English name Scientific name Local name Reference
1. Giant freshwater prawn Macrobrachium rosenbergii Golda chingri Akand and Hasan (1992), Mirza and Ericksen
(1996), Saifullah, Rahman, Jabber, Khan and
Uddin (2005)
2. Monsoon river prawn Macrobrachium malcolmsonii Chotka icha
3. Oriental river prawn Macrobrachium nipponense Icha/chingri
4. Freshwater prawn Macrobrachium villosimanus Dimua icha
5. Freshwater prawn Macrobrachium mirabilis Lutia icha
6. Freshwater prawn Macrobrachium birmanicus Thengua icha
7. Freshwater prawn Macrobrachium rude Goda icha
8. Freshwater prawn Macrobrachium dayanus Kaira icha
9. Freshwater prawn Macrobrachium lamarrei Icha
10. Freshwater prawn Macrobrachium dolichodactylus Icha
Freshwater prawn farming in Bangladesh NAhmed et al. Aquaculture Research, 2008, 1^14
The CARE GOLDA project operated in southwestBangladesh mainly Khulna, Bagerhat and Satkhiradistricts between 1996 and 2001 with funding fromDepartment for International Development (DFID),UK. The project provided technical assistance tosmall-scale farmers to increase their incomes andimprovement of socioeconomic conditions. The pro-ject also provided training to 15000 resource poorfarmers and credit through partner NGOs (Finan,Biswas & Muir 2001). The GNAEP was a Danish In-ternational Development Assistance (DANIDA) sup-ported project working from 1998 to 2006 in theNoakhali area in southern Bangladesh. From 2002,the project focused on integrated prawn farming toachieve a more positive impact on poverty alleviationby increasing income of the poor farmers (GNAEP2006; USAID 2006). By 2006, over 11000 mainlysmall-scale farmers were engaged in prawn culture.
Prawn farming area and farm size
Culture area
Around three-quarters of prawn farms are located inthe southwest part of Bangladesh which has beenidenti¢ed as the most important and promising areafor prawn culture, because of the availability of wildpostlarvae, favorable resources and climatic condi-tions, such as the availability of ponds, low lying agri-cultural land, warm climate, fertile soil, and cheapand abundant labor (Haroon1990; Ahmed 2001). In2002, there were an estimated 105000 prawn farmsin Bangladesh, of which 75000 (71%) were locatedin the southwest (Muir 2003a). At that time, therewere 30000 ha of land under prawn farming (Wil-liams 2003); this compares with 3500 ha in the mid1980s (Muir 2003a). At present, the prawn culturearea has increased to an estimated 50000ha
Figure 1 Map of Bangladesh showing the prawn farming districts and original location of prawn farming area inBagerhat.
Aquaculture Research, 2008, 1^14 Freshwater prawn farming in Bangladesh NAhmed et al.
(Khondaker 2007).This ¢gure is expected to risewiththe increasing expansion of prawn cultivation intonew areas. Prawn farming has been expanding ra-pidly in recent years, an average10^20% per annum(Williams & Khan 2001; DOF 2002a; Khondaker2007).
Farm size
Prawn farms are typically smaller than farms in thebrackishwater shrimp sector; an average 0.28 hacompares with 4.0 ha of shrimp farms (DOF 2002a;Muir 2003a).This ¢gure compares with prawn farmsmore than a decade ago which was averaged 0.35 hain Bagerhat district (Rutherford 1994). However,Ahmed (2001) reported that the average prawnfarm size was 0.23 ha in the Bagerhat area, withthousands of tiny farms and only a few largeunits; the largest farm size was1.01ha and the smal-lest was 0.06 ha. In the Mymensingh area, theaverage farm size is smaller than other parts ofBangladesh, an average 0.08 ha (Ahmed, Wahab &Thilsted 2007), while the average farm size in theNoakhali region was reported at 0.17 ha (Alam &Demaine 2003).
Prawn farming practices
There are two prawn farming systems in Bangladesh:pond and gher. Approximately 71% of farmers are in-volved in gher systems and the remainder in pondsystems (Muir 2003a). Although prawn farmingpractice is still traditional and extensive in nature,many farmers (20%) practice improved methodswhere prawns are cultivated semi-intensively. Exten-sive production typically use slightly modi¢edversions of traditional methods and are calledlow-density (10000^18000 postlarvae ha�1year�1)and low-input system. The system relies mainly onnatural productivity (e.g., phytoplankton, zooplank-ton and benthos) of the pond, but organic and inor-ganic fertilizers are occasionally used to promotethe growth of natural foods. Extensive feeding prac-tices generally use supplementary diets consisting ofa mixture of locally available feed ingredients, suchas rice bran, wheat bran, oil cake and ¢sh meal.Semi-intensive operations practice intermediatelevels of stocking (18000^30000 postlarvaeha�1
year�1) and other inputs. Farms with semi-intensivefeeding practices depend on commercially manufac-tured pelleted feeds.
Pond systems
In pond systems, farmers usually stock hatchery-pro-duced postlarvae during April to May. In the Noakha-li area where pond culture is now the main system,the stocking density is low at around 10000 post-larvaeha�1. In the ¢rst week of postlarvae stocking,50 g of wheat £our is applied per 1000 fry, and thefollowing week a double quantity is given. Di¡erentcarp species are also stocked by all farmers ata stocking density ranging from 2500 to3000 ¢ngerlings ha�1 (Lecou¡e 2005). Farmers ap-ply home-made feeds with ingredients either avail-able on their farm or bought from the local markets.Home-made feeds use a mixture of ¢sh meal, ricebran, mustard oil cake, molasses and wheat £our. Ifthose ingredients are not available, farmers can sim-ply feed the prawn with boiled wheat or cooked rice(Alam & Demaine 2004). Most farmers do not applyfeed on regular basis, but according to their ¢nancialability. In the Mymensingh area, commercial ¢shfeeds are used by most farmers to increase prawnproductivity. Feeding schedules of prawns are ob-served for three feeding periods: (i) starter ^ ¢rst 4weeks at the rate 6% of bodyweight, (ii) grower ^ sec-ond12 weeks at the rate 4% of body weight and (iii)¢nisher ^ last 8^12 weeks at the rate 3% of bodyweight (Ahmed, Ahammed & Lecou¡e 2007).Prawn harvest usually starts after 6^8 months of
stocking from October to December, but in perennialponds may continue up to May^June of the followingyear.The average size of prawnat harvest is from 60^150 g, with the larger sizes coming from the peren-nial ponds. The annual yield of prawns ranges from175 to 200 kg ha�1 in the Noakhali area (Lecou¡e2005), which compares an average 400 kg ha�1 inthe Mymensingh area (Asaduzzaman et al. 2007).
Gher systems
In southwest Bangladesh, the cultivation of prawn inmodi¢ed rice ¢elds is locally referred to as ‘gher’(Rutherford1994).The Bengali term‘gher’ is an enclo-sure made for prawn cultivation by modifying rice¢elds through building higher dikes around the ¢eldand excavating a canal inside the periphery to retainwater during the dry season (Kendrick1994). Accord-ing to Kampand Brand (1994), gher farming is a‘quiet,indigenous technological revolution’, suitable for thecultivation of prawn, ¢sh and rice. Gher farming canbe considered as amethod of integrated aquaculture^agriculture on one plot. During the rainy season
Freshwater prawn farming in Bangladesh NAhmed et al. Aquaculture Research, 2008, 1^14
the whole water body is used for the cultivation ofprawn and ¢sh. However, when the weather is drythen only the trenches are used for ¢sh and rice isplanted in the central part of the plot. The dikes canbe used for growing vegetables and fruits throughoutthe year (Chapman & Abedin 2002). The gher aregenerally situated in low lyingareas of the £oodplain,which are irregular in shape and cover hundreds ofhectares (New1995). The principal water sources forgher are rainfall, ground water and sometimes riverwater through canals.Most farmers practice integrated prawn farming in
gher systems. The gher design potentially providesgood opportunities for diversi¢ed production, withprimary dependence on prawn, ¢sh, rice and dikecrops (Fig. 2). Prawns are produced for export mar-kets while ¢sh, rice and dike crops are for local mar-kets and household consumption.The peak season of prawn farming in gher is from
May to January. Prawn postlarvae are stocked in Mayto June and harvested primarily from November toJanuary, a culture period of around 9 months. Farm-ers cultivate boro rice in the central plateau of the gherduring the dry season from January toApril and ori-ginally avoided cultivation of monsoon season amanrice during June to October when the prawns are inthe gher, because of the perceived negative e¡ects onprawn growth (Ahmed 2001). However, evidencefrom other countries suggests that concurrent ricewith ¢sh and prawn is a positive practice. Nguyen(1993) stated that integrating prawnculturewith ricefarming is ecologically sound and a good method ofdiversi¢cation in Vietnam, where prawns predateupon insects and improve soil fertility. Roy, Das andMukhopadhyay (1991) noted that in integratedprawn culture in deep water rice ¢elds, rice produc-tion has increased due to presence of prawn. Thispractice is now growing in Bangladesh, partly as a
result of the promotion of integrated pest manage-ment. Culture of a high value crop like prawn inrice ¢elds almost automatically restricts the use ofpesticide.A range of carp species is cultured with the prawn,
but these are harvested throughout the year. Farmersstock the Indian major carps such as, catla (Catlacatla), rohu (Labeo rohita) and mrigal (Cirrhinacirrhosus), as well as exotic carps, silver carp (Hypo-phthalmichthys molitrix), grass carp (Ctenopharyngo-don idella) and common carp (Cyprinus carpio). Theseare generally stocked at low densities ranging from2000 to 5000 ¢ngerlings ha�1 and traditionally atleast there is no particular stocking mix (Ahmed2001).Almost all farmers cultivate a variety of dike crops
on a small-scale and this practice has been steadilyincreasing. During the winter season, di¡erent typesof dike crops such as carrot, tomato, onion, mustard,long yard bean, spinach and pea are produced, whilecrops produce in the summer season include potato,ladies ¢nger (okra), sweet gourd, cucumber and chil-li. A range of short-cycle fruits is also produced ondikes such as banana, papaya and guava.
Production technology in gher systems
Stocking of prawns
Prawn culture in gher systems still remains depen-dent on wild postlarvae (Angell 1990, 1992; Ahmed2000; DOF 2002b). Traditionally, farmers prefer tostock wild postlarvae rather than hatchery-producedfry because, until recently, the production of thehatchery postlarvae has been limited and farmersconsider them to be of lower quality. The survival ofwild postlarvae is reported to be much higher thanthat of hatchery-produced fry. The average annual
(Ahmed 2001), ranging from 10000 to 30000(Rosenberry 1992; Muir 2003a). Most farmers di-rectly stock postlarvae without rearing in nurserysystems. However, in recent years a few farmershave started to use hapa (i.e., net enclosure) orseparate small ponds for nursing of postlarvae toimprove survival rate. In general, farmers rearpostlarvae for 4^6 weeks with a stocking rate from50 to 100m�2 (Ahmed 2001). According to SinghandVijiarungam (1992), better survival of stocks hasbeen reported when nursing of postlarvae is done innet cages.The livelihoods of around 400000 people, manyof
them women and children, are associated withprawn postlarvae ¢shing in coastal Bangladesh dur-ing April to June (Ahmed, Ahammed, Rahman, Be-gum & Haque 2005; USAID 2006). Indiscriminate¢shing of postlarvae with high levels of by-catch(i.e., non-target species caught incidentally) has animpact on biodiversity in coastal ecosystem and hasprovoked imposition of restrictions on postlarvae col-lection. In September 2000, DOF imposed ban onwild postlarvae ¢shing (DOF 2002b). This ban hasnot been strictly enforced because of the limitedavailability of hatchery seed. Nevertheless, theban has been one of the factors that have stimulatedthe expansion of the prawn hatchery sector overthe last few years. In 2000, there were only 16hatcheries with a total production of 10 millionpostlarvae a year. In 2007, there exist 81 prawnhatcheries, although only 38 (47%) are operationalin the sense of producing around 100 million post-larvae, 20% of total demand (Winrock Inter-national 2007). Lack of knowledge of the complextechnology of prawn hatcheries, inadequate skilledmanpower and insu⁄cient supply of wild broodare important reasons for the poor results of manyhatcheries.
Feeds and feeding of prawns
Supplementary feeds are used by all farmers in ghersystems. Avariety of feeds are used but the preferredfeed is the freshwater snail, Pila globosa (Ahmed2001). The use of snail meat as prawn feed is wide-spread in prawn farming areas and snail populationsare reported to have declined heavily due to excessiveharvesting. A wide variety of people including wo-men and children are involved in snail harvestingduring June to October. Overall, the supply of snails
has generated a number of employment opportu-nities, in catching, processing, transporting andmar-keting activities.An average 66.5 kg ha�1day�1of snail meat is ap-
plied for feeding of prawns during June to October(Ahmed 2001). In general, chopped snail meat is gi-ven twice a day in the morning and evening. If exces-sive snail meat £oats up in the water, feed supply isreduced, and it is increased if it does not £oat in thewater. The supply of snail is irregular and thereforefarmers also use home made feed mixing by cookedrice, rice bran, oil cake and ¢sh meal, or sometimesuse industrially manufactured pelleted feed. In theearly 1990s, the majority of pelleted feed was im-ported from Thailand and Taiwan, while most farm-ers currently use locallymade pelleted feed for prawnfarming.
Fertilization
Prawn farmers use two types of fertilizer: organic,mainly cow dung, and inorganic ^ urea and triplesuper phosphate (TSP). The purpose of using fertili-zers in the gher is to create conditions, which help toincrease the production of good quality of naturalfeed. Almost all farmers apply cow dung in their gher,which is relatively cheap and available. On the otherhand, the use of inorganic fertilizer is not widespreadand onlya few farmers use amixture of urea andTSPtogether with cow dung. On average, annual fertili-zation rate is1467 kgha�1of cow dung,403 kg ha�1
of urea and 217 kg ha�1of TSP at varying frequency(Ahmed 2001). Farmers also use lime in their gher,which is an important factor for prawn farming tomaintain a healthy and productive environment toprevent disease. The average annual liming rate is247 kg ha�1.
Harvesting of prawns
In gher systems, the peak season of prawn harvestingis from November to January. Farmers harvest theirprawns by using cast nets and seine nets, usually net-ting several times at a few weeks’ intervals (Ahmed2001). Cast nets are generally used for small gherand seine nets for large gher. A cast net can be oper-ated by a single farmer, while a seine net is operatedbya group of 3^4 commercial harvesters rather thanthe producers themselves.The partial harvesting of larger prawns allows
smaller prawns to grow. Harvested prawns are kept
Freshwater prawn farming in Bangladesh NAhmed et al. Aquaculture Research, 2008, 1^14
in aluminium or plastic containers. Ideally, theprawns are cleaned with tube-well water and kept incontainers until they are sold to traders. Farmersgrade all head-on prawns by size and weight and sellthem to the prawn traders. About 50% of productionis grade 20, o10% is grade 5 and 10, although thismay increase in perennial gher systems. The remain-ing is equallydivided betweengrades 30 and 50, withanything smaller than grade 50 restocked ratherthan harvested (Muir 2003a). The average farm-gateprice of prawns depends ongrade and varies betweenUS$ 2.6 and 6.5 kg�1 (Table 2).
Constraints of prawn farming
Despite the great potential of freshwater prawn farm-ing in Bangladesh, successful commercial culturefaces a number of constraints including high produc-tion costs, insu⁄cient supply of postlarvae, poorquality of feed, water pollution, disease and £ood(Ahmed 2001). The expansion of prawn farming de-pends on availability of postlarvae. The major bottle-neck for further expansion of prawn culture is thelack of adequate supply of postlarvae. Catches of wildpostlarvae have declined in recent years because ofover ¢shing, use of destructive gears, environmentaldegradation and pollution. Disease is a common andmajor problem of prawn farming in Bangladesh. Awide variety of diseases are found including shell dis-eases or black spot, white spot and gill disease (Ma-cRae, Chapman, Nabi & Dhar 2002). Black spot, themost widespread disease of prawn from postlarvaeto harvest size, is caused by bacteria and sometimes,later, by fungus (Cai, Wang & Yang 1997), causingmortality and also reducing the value of harvestedprawns through discoloration. A number of socialconstraints have also been accompanied with theprawn farming sector in Bangladesh (Bundell &May-bin 1996; Ito 2004). Prawn farmers are socially, eco-
nomically and educationally disadvantaged andlacking their own ¢nancial resources, are heavily in-debted to traders and middlemen.
Prawn productivity
The average annual yield of head-on prawns in Ban-gladesh was reported to be 336 kg ha�1 (Muir2003a). The present production levels suggest thatthe average productivity of prawn has increasedin recent years, probably as farmers have becomemore con¢dent to increase stocking densities andfeeding levels. In the early1990s, the average yield ofprawnwas only168 kg ha-1, whichwas lowdue to thetraditional farming method and the relatively lowlevel of inputs (Rahman 1994). However, in the late1990s, reported yields had increased, with a typicalyield of 200^250 kg ha-1 being obtained (Rahman1999), while Hoq, Islam and Hossain (1996) reportedthat prawn production when reared together with¢sh, varied from 162 to 428 kgha-1. Nevertheless,most of the prawns are cultivated using extensivemethods in Bangladesh and productivity is low com-pared with other countries (Table 3). Countries witha larger export market than Bangladesh use moreintensive techniques and have signi¢cantly higheryields.The quantity of total prawn production in Bangla-
desh remains rather uncertain because productionstatistics often do not distinguish between prawnand shrimp. In 2004^2005, total annual productionof prawn and shrimp was 82661tons, of which only25^30%was prawn (DOF 2006).The total productionof prawn and shrimp has been increasing since1995though at a rather irregular pace (Table 4). The aver-age annual growth of prawn production over the lastdecade (1995^2005) was11.56%.
Table 2 Grade and average farm-gate prices of head-onprawns in southwest Bangladesh
Grade
No. ofhead-onprawns kg�1
Averageweight of aprawn (g)
Averageprice(US$ kg�1)
5 5 or less 200 6.5
10 6–10 125 5.3
20 11–20 70 4.3
30 21–30 40 3.6
50 31–50 25 2.6
Table 3 Comparison of prawn yields in Bangladesh andother producing countries
Country
Prawnproduction(kgha�1year�1) Reference
Bangladesh 336 Muir (2003a)
China 1,500 Weimin and Xianping (2002)
India 600–1,000 Raizada, Chadha, Javed, Ali,
Singh, Kumar and Kumar
(2005)
Taiwan 1,500 New (1995)
Thailand 2,338 Vicki (2007)
Vietnam 1,000–1,500 Ridmontri (2002)
Aquaculture Research, 2008, 1^14 Freshwater prawn farming in Bangladesh NAhmed et al.
Freshwater prawn farming in Bangladesh had notbeen associated with any of the negative environ-mental consequences for which marine shrimp pro-duction has received so much criticism (Csavas1993;Phillips, Lin & Beveridge 1993). However, in recentyears there are some concerns about its long-termenvironmental sustainability. The development ofprawn farming has brought about several environ-mental impacts due to gher construction, wild post-larvae collection and snail harvesting (Fig. 3). In
southwest Bangladesh, large areas of wetland havebeen used for gher construction. The reduction inwetlands is likely to have negative impacts includingreduced wetland biodiversity, loss of aquatic plantsand wildlife, increased £ood risks and reduced riceproduction (Nuruzzaman 1993; Ahmed 2003). De-creased rice production has meant decreased avail-ability of paddy straw, used for both cooking fuel andfodder for cattle. Construction of gher has also re-sulted in a reduction of grazing land for livestock,especially cows.Wild prawnproduction has signi¢cantly decreased
due to uncontrolled ¢shing of postlarvae, which maybe threat to their natural population. Large-scale col-lection of postlarvae is likely to a¡ect the recruitmentof other species (Ahmed 2003). A huge number ofother ¢sh fry are caught and discarded along withthe prawn postlarvae due to the ¢ne mesh nets used,which may have severe long-term impacts on coastal¢sh production (DOF 2002b).Negative environmental e¡ects also appear from
over harvesting of snails for use as prawn feed. Thesnail population has become extinct in most parts ofBagerhat district due to excessive harvesting duringthe monsoon, which is the peak season of theirreproduction (Ahmed, Miah & Islam 1997). Over-harvesting snails has created problems of disposal oflarge quantities of snail shells, which has resulted inpollution and blockage of canals and other openwater bodies. The canals have su¡ered from abuse
and neglect (i.e., not used for ¢shing). The disposal ofsnail shells after the meat has been extracted posesenvironmental problem ^ the smell of rotting snailspermeates the air and the open waterways have be-come polluted (Gain1998; Khan1998).
Economics of prawn farming
Production costs
In southwest Bangladesh, annual prawn productioncosts an average US$1343 ha�1, of which variablecosts and ¢xed costs are US$992 ha�1 (74%) andUS$351ha�1 (26%) respectively (Ahmed 2001).Vari-able costs in prawn culture are cost of seed, feed,fertilizer, labor (family and hired), harvesting andmarketing, and miscellaneous. Fixed costs includedepreciation (water pump, net, feed machine, etc),land use and interest on operating capital (Shang1990).Within variable costs, seed and feed dominateall other costs averaging 39% and 33% of total costsrespectively (Ahmed 2004). Muir (2003a) reportedthat prawn production costs comprise 28% of seed,21% of feed and only 4% of labor. Despite the bene¢tsof prawn farming, the costs of inputs are highand areoften beyond the ¢nancial capacity of most small andmarginal farmers.
Finance of prawn farming
A quite substantial amount of money is required inprawn cultivation. Costs of prawn production haveincreased signi¢cantly in recent years as a result ofincreased price of seed, feed and wage rates of la-borers. One of the main problems for small and mar-ginal farmers is the shortage of operating capital.Inadequate and costly ¢nance is therefore a con-straint for the e⁄cient and pro¢table prawn farmingby resource poor farmers.A study in southwest Bangladesh reported that
68% of farmers use their ownmoney for prawn farm-ing while the rest receive loan (Ahmed 2001). Theaverage amount of credit received by a farmer isUS$228 year�1. Farmers apply awide variety of stra-tegies to develop prawn farming. The ¢nance comesmainly from a broad mix of personal and informalsources. Farmers primarily ¢nance their prawnfarming operations through disposing of householdassets. Some have their own capital, either savingsor proceeds from sales of personal assets, especiallycows, gold jewellery and timbers (Kendrick 1994).
Cattle are the most common assets to be sold fordeveloping a prawn farm.Access to credit is considered to be one of the im-
portant factors in£uencing prawn production. Overrecent years several institutions providing credit tothe prawn farmers include banks, NGOs, prawn tra-ders and local moneylenders (Fig. 4). Local branchesof national banks provide credit to the prawn farm-ers, collateral against land at a 15% yearly interestrate. The Grameen Bank, a specialized bank for microcredits that was awarded the Nobel Peace Prize for2006, is active in several villages of prawn farmingareas.
Net return
In southwest Bangladesh, the annual net return ofgher farming is an average US$1430 ha�1 (Muir2003a). The combination of prawn, ¢sh and rice cul-tivation in gher systems give particularly good poten-tial returns. The annual gross revenue of prawnproduction average US$1601ha�1 (69%), while thatof ¢shand rice production is US$330 ha�1 (14%) andUS$389 ha�1 (17%) respectively (Ahmed 2001). The
Money supply line
Prawn supply line
33%
12% 10%
45%
Prawn farmers
Prawn traders
Moneylenders
Processing plants
Banks
Export markets
NGOs
Agents
Figure 4 Credit supply chain from di¡erent sources toprawn farmers (adapted from Ahmed 2001).
Aquaculture Research, 2008, 1^14 Freshwater prawn farming in Bangladesh NAhmed et al.
net return of prawn farming represents 68% of totalturnover (Muir 2003b). The net return in the low in-put systems in Noakhali is rather lower, an averageUS$650 ha�1 (GNAEP 2006).
Prawn marketing, processing and export
Prawn marketing
In Bangladesh, prawnproductionand its commercialviability depends on international markets. Thesemarkets have grown strongly in volume over the lastdecade. Freshwater prawn marketing is almost en-tirely managed, ¢nanced and controlled by a groupof powerful intermediaries (Ahmed, Ahammed, et al.2007). The market chain from farmers to interna-tional markets passes through a number of interme-diaries: prawn traders, agents and processing plants(Fig.4).In southwest Bangladesh, the peak season of
prawnmarketing is fromNovember to January. Farm-ers tend to sell their head-on prawns to traders in lo-cal markets. Farmers commonly use vans, rickshaws(i.e., pedal tricycle) or walk to transport the prawnsfrom the gher to the markets. Sometimes suppliersbuy prawns from the farmers at the gher side and car-rying them to the prawn traders. Prawn traders arenormally based in local markets near to prawn farm-ing areas. Prawn traders supply prawns directly, orvia agents, to the processing plants within 1^2 daysof purchase, during which they are kept on ice. Con-signments are sent once su⁄cient quantities havebeen obtained, an average 225 kg day�1trader�1
(Ahmed 2001). Trucks and pickups are commonlyused to transport prawns to the processors. Plasticcontainers with polythene covers are commonlyused for keeping the prawns during the transport.The £owof prawns from gher to the processing plantsis between 24 and 48 h (Muir 2003a). Finally, proces-sing plants export frozen headless prawns to interna-tional markets.Apart from the generally unhygienic conditions
and practices mentioned above, there are a numberof constraints in prawn marketing including, poorroad and transport facilities, high transport costs, in-accurate weighing, poor supply of ice, crushingprawn during storage in the depots, power cuts inprocessing plants, political disturbances (i.e., strikesand road blocks) and labor unrest (Muir 2003a;Ahmed, Ahammed, et al. 2007). In addition to theseproblems, farmers are in a particularly weak position(i.e., no bargaining power on price) in relation to in-
termediaries of prawn marketing systems. It is there-fore important for Bangladesh to improve itsmarketing chain to cope with emerging require-ments of the international market.
Processing
There are124 prawnand shrimp processing plants inBangladesh of which 35 are currently operational inKhulna, 38 in Chittagong and 51 have either closeddown or are waiting approval of a quality inspectionlicense (Muir 2003a). License allocation requires de-velopment of a hazard analysis and critical controlpoint (HACCP) manual and all plants are subject to aquality control by DOF. The collective capacity ofthese plants is around 165000 tons, this allows forprocessing of 825 tons day�1.The removal of the shell and legs during proces-
sing leads to an average 45% of decrease in weight.Process wastes are sold to local markets for humanconsumption. An average of 575 contract workersboth men and women are employed in a typicalprawn processing plant during the peak season fromNovember to January (Ahmed 2001). Women areusually engaged in cleaning and beheading ofprawns, while men work more closely with machin-ery, block freezing and packaging (USAID 2006). Pro-cessing plants transport their prawns to Mongla orChittagong ports using their own refrigerated vehi-cles. Shipping agents load the prawns into freezercontainers, whichare then loaded into ships destinedfor international markets. A typical processing plantexports an average 4.5 tons of prawns daily duringthe peak season (Ahmed 2001). Processing plants ex-port frozen headless prawns either as individuallyquick frozen or block frozen.Bangladesh has been facing problems inmaintain-
ing quality standards in prawn processing. Raw ma-terial contamination may occur due to traditionalpractice in the production process and inadequatecare during prawn marketing. In 2000, most of theAsian countries increased their prawn exports tothe US market with the exception of Bangladesh.Banning of consignments occurred in 2002 follow-ing detection of nitrofurans and pathogenic bacteriain a prawn lot exported from Bangladesh (Muir2003a). In recent years, DOF has amended the ¢shinspection and quality control act to incorporateHACCP principles. The sub-district and district¢sheries o⁄cers have been instructed o⁄cially toenforce the inspection and quality control act under
Freshwater prawn farming in Bangladesh NAhmed et al. Aquaculture Research, 2008, 1^14
which theycanvisit prawn farms, hatcheries, feed in-dustries, depots and processing plants, and take ac-tion on the defaulters. However, there have beenfurther cases of rejection of prawn due to nitrofurancontamination in 2005^2006, raising doubts aboutthe e¡ectiveness of the inspection process. Followinga recent EuropeanUnion inspection, with the help ofthe Bangladesh Frozen Food Exporters Association,the DOF is establishing a laboratorycapable of testingfor nitrofuran metabolites in country. However, a to-tal traceability system is also needed if this is to iden-tify the sources of the contaminants.
Export
Bangladesh was once a major exporter of prawncaught by artisanal ¢shers in rivers, lakes and £ood-plains. In the early1990s, the vast majority (490%)of the prawns exported from Bangladesh derivedfrom natural resources, with an estimated 60% fromthe Khulna and Bagerhat areas, 35% Comilla andNoakhali areas and 5% Cox’s Bazaar area (DIFTA1993). Bangladesh was thus well placed to developan export market for farmed output. Owing to the im-portance of prawn as an export product, the govern-ment had declared prawncultivation to be of primaryindustry status and designed a speci¢c support pro-gram to boost production (Datta1995).Prawn is a highly valued product for international
markets and almost all Bangladeshi prawns aretherefore exported. In 2004^2005, Bangladesh ex-ported 46533 tons of prawn and shrimp valued atUS$380million (Table 5), of which 25^30%mayhavebeen contributed by prawn. Of the total export in
2004^2005, 48.74% was sold to Europe, 34.78% tothe United States and11.26% to Japan (USAID 2006).Demand for prawn is increasing the US and Eur-opean markets; especially Belgium, the United King-dom, Germany, the Netherlands and Denmark hvelargely accepted Bangladeshi prawn. Although theJapanese market has declined, new markets haveemerged in Asia such as Hong Kong, Singapore,Malaysia andThailand (Muir 2003a; USAID 2006).Despite rising market demand, the prices of prawn
have been declining in recent years as supply has in-creased. The trend in prawn prices was consistentlyupwards between 1970 and 1990. Thereafter, pricesof prawn in the major markets largely stagnated and,since the late 1990s, have begun to decline in somemarkets (USAID 2006). In 2006, the average pricesof Bangladeshi prawn for export markets varied fromUS$7.7 to 15.4 kg�1 depending on grade (Table 6),compared with the range of US$7.7^19.8 kg�1 in1996 as quoted by Borua (1996). This suggests thatthe export price of prawns has declined over recentyears.
Livelihoods of the poor
Freshwater prawn farming sector o¡ers diverse liveli-hood opportunities for the rural poor in Bangladesh.It is estimated together with published sources andpersonal communications with concern depart-ments that around 300000 people are directly in-volved in prawn production, marketing andassociated activities in addition to 400000 people ofprawn postlarvae ¢shing. A range of associatedgroups such as prawn farmers, wild postlarvaecollectors, fry traders, snail harvesters, feed traders,
Table 5 Export of prawn and shrimp over the years1995^2005
prawntraders and day laborers includingwomenandchildren are involved in this sector. A network forpostlarvae trading has developed involving ¢shers,intermediaries, traders, local agents and farmers.Similar networks for feed trading and prawn market-ing have established. The opportunities for daylaborers to ¢nd work have increased signi¢cantly inprawn farming. Labor is required for gher construc-tion, postlarvae marketing, feed trading, snail break-ing, prawn harvesting and marketing. In markets,laborers perform postharvest tasks that includehandling, cleaning, sorting, grading, icing and trans-portation of prawn. Additional employment opportu-nities are also generated in hatcheries, commercialfeed industries, ice factories, processing plants andin the transport sector ranging from rickshaws andvans to the large vehicles which carry prawns to pro-cessing plants. Processing plants employ around30000 people, about 60% of whom are women(USAID 2006). Women also play a pivotal role inprawn farming. They are involved in various facets,including feeding of prawn, fertilization, gher super-vision and management, prawn harvesting, posthar-vest handling and dike cropping (Ahmed 2005).
Conclusions
Freshwater prawn farming plays an important role inthe economyof Bangladesh, earning valuable foreignexchange and contributing to increased food produc-tion, diversifying the economyand increased employ-ment opportunities. In spite of several problems, thepractice of prawn farming has o¡ered anopportunityto increase incomes for farmers and associatedgroups. Freshwater prawn farming is particularlyap-propriate for small-scale units, though, to exploitmarkets, producer groups and marketing organiza-tions are essential. Prawns require particular careduring harvesting, processing and marketing. Poorquality prawns have been marketed in the past. Thismust be avoided, particularly if export potential is tobe achieved and sustained. The use of suitable har-vesting, handling and processing techniques are alsoimportant to ensure a quality product for export mar-kets. It would appear that the most appropriate formof action would be to enhance quality, traceabilityand marketing systems.The future for prawn farming is bright but requires
dynamism to exploit fully. A range of public and pri-vate sector investments and initiatives are needed torealize the potential for growth and expanding eco-
nomic output from this sector. The realization of itspotential must be aided by improvements in produc-tion technology and hatchery operation. Betterbroodstock management is required for successfuloperation of prawn hatcheries. A number of low-costlocally produced ingredients feed industries wouldhelp to increase farmer’s pro¢t margins, reduce thenegative environmental impacts of snail harvesting,and increase job opportunities.Although numerous constraints can be recog-
nized, the prospects for prawn farming are positive,and the recent record of production and export valuedemonstrates the emerging strength of this sector.However, a number of signi¢cant challenges particu-larly socioeconomic and environmental issues are vi-tal in translating its bene¢ts e¡ectively to thethousands of rural poor involving in this sector.The issues of environmental sustainability of
prawn cultivation, while clearly not as negative asthose of marine shrimp culture in Bangladesh,are nevertheless poorly understood. Thereforeresearch would be required as quantitative andqualitative environmental impacts for sustainableprawn farming. In addition, research in areas suchas seed and feed production may need to be givenparticular attention, considering existing techno-logy, the transfer, adaptation and development ofnew technology.
Acknowledgments
The study was supported through the UK Depart-ment for International Development (DFID) as partof theirAquaculture and Fish Genetics Research Pro-gram (AFGRP). The opinions expressed herein arethose of the authors and do not necessarily re£ectthe views of DFID. The authors would like to thankall those people whowillingly gave valuable informa-tion for writing this paper.
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