Aquaculture production systems in intertidal areas of
Bangladesh: a review
Md. Jahangir Alam Bangabandhu Sheikh Mujibur Rahman Agricultural University
Gazipur-1706, Bangladesh
Contents Introduction .................................................................................................................................................. 4
Importance of brackishwater aquaculture ............................................................................................... 4
Aquacultures contribution to livelihoods ................................................................................................. 8
Historical development of brackishwater shrimp farming in Bangladesh .................................................. 10
Main shrimp farming areas ..................................................................................................................... 10
Ownership of shrimp farms .................................................................................................................... 11
Historical development of shrimp production ........................................................................................ 11
Brackishwater aquaculture practice ........................................................................................................... 13
Cropping pattern in brackishwater aquaculture ..................................................................................... 13
Shrimp aquaculture systems in the coastal zone .................................................................................... 14
Rice-‐based shrimp farming ......................................................................................................................... 16
The change from rice to shrimp .............................................................................................................. 16
Climatic and hydrological suitability for rice-‐shrimp system .................................................................. 17
Shrimp farming in rotation with paddy ................................................................................................... 18
Pre-‐stocking management ...................................................................................................................... 19
Stocking of shrimp in rice-‐shrimp systems ............................................................................................. 20
Water quality .......................................................................................................................................... 21
Fertilization of ghers ............................................................................................................................... 21
Shrimp aquaculture feeds ....................................................................................................................... 22
Health and disease management ........................................................................................................... 23
Production and economics of shrimp aquaculture ..................................................................................... 24
Wet season rice cultivation ......................................................................................................................... 29
Rice varieties and production ................................................................................................................. 29
Water and nutrient management ........................................................................................................... 30
Integration of aquaculture with wet-‐season rice cultivation in rice-‐shrimp system .............................. 31
Environmental impact of shrimp farming ................................................................................................... 32
Social impact of shrimp farming ................................................................................................................. 35
Opportunities for increasing brackishwater aquaculture productivity and profitability............................ 37
Semi-‐intensive shrimp farming ............................................................................................................... 38
iversifica*on in brackishwatr aquaculture …………-‐………………………………………………………………………………………………………………..39 Conclusion ……………………………………………………………………………………………………………………………………………………………………………… 40 References …………………………………………………………………………………………………………………………………………………………………………………42
Brackishwater aquaculture: historical development
• Farming of shrimp, which is believed to have started in 1829 in the southwest Sundarbans mangrove area (Paul, 1995),
• An age-old practice in the coastal areas of Bangladesh involving the most traditional way of trapping-holding-growing shrimp in polyculture with shellfish and finfish species in tidal and low-lying areas isolated by dykes (locally called “bheri”).
• Polderization started from early 60s brought an end to traditional shrimp trapping and holding systems in these areas (Paul, 1995, Williams, et al., 2003)
Brackishwater aquaculture: historical development
• Controlled shrimp (P. monodon) farming within polders was resumed in early 70s in polders within the embanked areas (Akhtaruszzaman, et al., 1985).
• Economic importance of shrimp and unviability of rice production together provided a catalyst for an accelerated development of shrimp farming within the polders,
• FW prawn (M. rosenbergii) farming started in early 80s (Abedin et al., 2001).
• Shrimp farming was declared as industry in the 2nd FYP (1980-85).
• In 1979-80, about 19,500 ha of coastal land were under bagda (P. monodon) and 3,500 ha under golda (M. rosenbergii) cultivation (Ahmed, 1988).
• BW aquaculture farming area expanded rapidly (DoF, 2011) • 162% from 1984 to 1997 • 3.19%, from 1997 to 2002 • 58.86% from 2002 to 2010
Brackishwater aquaculture: historical development
20
87 108
138 141 141
203 217 217
246 276
0
50
100
150
200
250
300
Farm
area (x000)ha
)
Financial Year
107962
202576
29792
65200
0
50000
100000
150000
200000
250000
Area (h
a)
Khulna Division ChiLagong Division
79% shrimp and 21% golda
• Shrimp farming is majorly in four coastal districts • 74% in Khulna region
Brackishwater aquaculture: historical development
Districts
Shrimp farming area (ha) 10-‐11
Bagda Golda Total
Bagerhat 47900 18556 66456
Khulna 35557 13960 50517
Satkhira 60348 7664 68012
Barguna 108 179 287
Barishal 00 686 686
Patuakhali 2478 1733 4211
Pirojpur 420 1440 1860
Cox’s Bazar 62907 00 62907
Khulna, 202576, 74%
Barishal, 7128, 2%
ChiLagong, 65200, 24%
Costal division-‐wise shrimp/prawn farm area (ha) (2010-‐11)
• Farm ownership by absentee operators in larger ghers (11-37 ha) was common earlier.
• Presently most of the farms (80%) are operated by the landowners.
• Farm size has been reduced gradually over the years to an average of 8-10 ha.
Brackishwater aquaculture: historical development
• Shrimp (both bagda and golda) production increased over the period
• The output growth in shrimp production up to 1990s was mainly the result of the expansion of the farm area.
• Per ha bagda and golda procuction production averaged approximately 245 and 500 kg/ha, respectively in 2008-09
Brackishwater aquaculture: historical development
14.773
17.889
18.235
18.624
19.489
20.335
23.53
28.302
34.03 46.223
52.272
62.167
63.164
64.647
64.97
65.579
66.703
75.167
82.661
85.51
86.84
94.211
102.854
87.972
124.648
0
20
40
60
80
100
120
140
Prod
uc?o
n (x10
00 m
t)
Financial Year
• Golda production share is increasing • Production (incidental) of M. monoceros in also increasing • Finfish production increased from 47839 mt (2008-09) to
60290 mt (2010-11)
Brackishwater aquaculture: historical development
Bagda (P. monodon)
51%
Golda (M. rosenbergii)
27%
Harina (M. monoceros)
12%
Chaka (P. indicus) 2%
Other shrimp/prawn 8%
Bagda (P. monodon)
45%
Golda (M. rosenbergii)
32%
Harina (M. monoceros)
14%
Chaka (P. indicus) 2%
Other shrimp/prawn 7%
2008-‐09 2010-‐11
Shrimp cropping pattern
Months J F M A M J J A S O N D
Satkhira
Year-round bagda
Bagda-rice rotation
Khulna
Bagda-rice rotation
Golda-rice integration
Bagerhat
Bagda-rice rotation
Golda-rice integration
Cox’s Bazar
Year-round bagda
Bagda-salt rotation Legend: Bagda Rice Golda-fish Salt
Brackishwater aquaculture prac*ces
Shrimp aquaculture produc*on
systems
SHRIMP CULTURE SYSTEM
Tradi*onal extensive (85%) Semi-‐intensive
No Prepara*on No fer*liza*on
Mostly naturally trapped seed
PRODUCTION LEVEL
Improved extensive (14%)
Prepara*on Fer*liza*on
External seed stocking Prepara*on Fer*liza*on
External seed stocking Feeding (inconsistent) Water management
Prepara*on & fer*liza*on External seed stocking Formulated feeding Closed system water
management Aera)on
Low yield 50-‐250 kg/ha Medium yield: 250-‐750 kg/ha
High yield 1000-‐2500 kg/ha
Shrimp-‐rice produc*on system
Modified ader DaLa, 2001
Dry season shrimp culture management in
shrimp-‐rice system
Management measures Produc?on Authors Prepara?on Stocking Grow-‐out Survival
rate (%) Yield rate (kg/ha)
• Pond drying and ploughing • Liming () depending on soil pH • Fer?liza?on: cow dung @ 500kg/ha; MOC
@ 100 kg/ha; TSP-‐urea & 35 kg/ha (3:1 ra?o)
• 2.0 -‐ 2.5/m2 • Single
stocking
• Water depth 40-‐100 cm • Water exchange during new
and full moon • Fer*liza*on with urea and
TSP () depending natural food availability.
• No feeding
39 -‐ 41 231 -‐ 299 Roy et al. (1999)
• Pond drying and ploughing • Liming () depending on soil pH • Fer?liza?on: cow dung @ 500kg/ha; MOC
@ 100 kg/ha; TSP-‐urea & 35 kg/ha (3:1 ra?o)
• 1.5-‐1.75/m2
• Treated in 100 ppm formalin solu*on for 30 minutes
• Single stocking
• Water depth 1-‐1.2 m • Water exchange during new
and full moon • Fer*liza*on @ 15 kg/ha
(TSP:Urea=3:1) ader each water exchange
• Liming with CaCO3 @ 150-‐250 kg/ha, as and when required
49 -‐ 58 334 -‐ 448 Ahmed et al. (1999)
• Pond drying and ploughing • Applica?on of liquid insec?cides
(thiodan) at the first water intake • Liming @ 67-‐82 kg/ha • Fer?liza?on: cow dung @ 700-‐1000 kg/
ha; MOC @ 35-‐45 kg/ha; TSP @ 30-‐55 kg/ha; urea 15-‐20 kg/ha; DAP @ 30-‐55 kg/ha
• 1.4 – 2.0/m2
• Mul*ple stocking
• Water exchange every 4-‐6 days at every lunar cycle
• No fer*liza*on and feeding
24 -‐ 25 146 -‐ 153 Alam and Phillips (2004)
Management measures Produc?on Authors Prepara?on Stocking Grow-‐out Survival rate (%) Yield rate (kg/
ha)
• Pond drying and ploughing • Liming with dolomite @ 200-‐250 kg/ha • Fer?liza?on: urea:TSP (1:1) @ 100 kg/ha
• 1.8 – 2.2/m2
• Single stocking
• water depth • Water exchange at every
lunar cycle • Irregular inorganic
fer*liza*on and feeding with rice bran in smaller (2.32 ha) and medium (6.13 ha) ghers
• No fer*liza*on in larger (54.24 ha) ghers
• Smaller ghers: 37-‐ 71
• Medium gher: 35-‐39
• Larger ghers: 7-‐24
• Smaller ghers: 164-‐277
• Medium gher: 155-‐164
• Larger ghers: 29-‐121
Islam et al. (2005) Milstein et al. (2005)
• Pond drying • Liming with CaCO3 @ 250 kg/ha • Applica?on of Fostoxin (1 tb/210c2 at first
water intake • Fer?liza?on with TSP and urea (2:1) @ 35
kg/ha
• 2.6 -‐ 3.6/m2
• Single stocking
• Water depth 83-‐95 cm. • Applica*on of lime @ 50
kg/ha, as required • Fer*liza*on with TSP and
urea (2:1) @ 30 kg/ha, as required
• Feeding with prepared diets
63-‐74 400-‐533 Islam and Alam (2008)
• Peripheral canal of 1.5 m depth • Pond drying • Liming with CaO @ 250 kg/ha • Applica?on of Fostoxin (1 tb/20t of water)
at first water intake • Fer?liza?on with urea @ 1 ppm; TSP @ 2
ppm and MP & 0.5 ppm
• 3.0/m2 • Single
stocking
• Water depth 31-‐44 cm • Water exchange as
required • Applica*on of 0.6-‐0.8 ppm
dolomite at every 12 days • Applica*on of urea @
0.5-‐1.0 ppm, TSP @ 1.0-‐1.2 ppm and MP @ 0.3-‐0.4 ppmFeeding with prepared diets
25 32 168-‐226 Islam et al. (2009)
Dry season shrimp culture management in
shrimp-‐rice system
Management measures Produc?on Authors Prepara?on Stocking Grow-‐out Survival
rate (%) Yield rate (kg/
ha)
• Drying • Liming with CaO @ 250
kg/ha • Bleaching(@ 25 ppm) at
first water intake • Fer?liza?on: TSP @ 3
ppm and urea @ 2.5 ppm
• 3.0 – 5.0/ m2 • Single and
double stocking
• Water depth 45-‐80 cm • No regular water exchange,
but replenishment of any loss • Applica*on of 7-‐8 ppm
dolomite, 1.25 ppm urea and 1.5 ppm TSP at every 15 days interval
• Feeding with commercial diet
27-‐36 162-‐584 Alam et al. (2010)
• Pond drying • Liming with CaCO3 @ 250
kg/ha • Applica?on of Fostoxin
(1 tb/210c2 at first water intake
• Fer?liza?on with TSP and urea (2:1) @ 35 kg/ha
•
• 3.0/ m2 • Single stocking
• Water depth 83-‐95 cm. • Applica*on of agricultural
lime @ 250 kg/ha ader every raining
• Fer*liza*on with TSP and urea (2:1) @ 30 kg/ha, as required
• Zeolite gold @ 50 kg/ha and Gasonex @ 0.5 kg/ha
• Feeding with prepared diets
58-‐73 417 – 615 Islam and Mahmud (2010)
Wet season rice cul*va*on
• Jotabalam, Ghunshi, Hokoz - local varieties mostly
cultivated in the shrimp farms.
• Yield varies from 1-2 t/ha
• Under the CP#10 project HYVs viz., BR-23, BRRIdhan-40, BRRIdhan-41 yielded 4-5 t/ha
• Not much nutrient application. However, in shrimp-based rice farming, application of urea (N) at the rate of 75 kg and TSP (P) 37.5 kg/ha after 24 and 60 days of transplanting respectively, has been recommended.
• Under CP#10 project, the benefit of integrating aquacul ture wi th r ice cu l t ivat ion has been demonstrated.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Wet season Dry season
Gher preparation
• Water depth- 60-80 cm • Single stocking:
@ 3-5/m² • Yield: 350-550 kg/ha • NR: 0.75-1.00 lakh/ha (1:1.9)
Golda
GIFT 5,000-10,000/ha at 1:1 ratio
Yield: • Rice: 4-5 t/ha. • Fish: 200-250 kg/ha • Prawn: 70-90 kg/ha
Seedling
Bagda
Rice
Improved rice (aman)-shrimp system
HYVs: BR 23/40/41
68,337a
48,908b 43,160b
Control 11.69
0
10
20
30
40
50
60
70
80
90
June July August
Net re
turn ('oo
o Tk./ha
)
Prawn stocking ?me
Prawn GIFT Rice
37.9045.50
67.50
13.29b23.30a24.64a
0
20
40
60
80
100
120
140
RG RGP RP SS DS3/2 DS2/3
Culture treatments
Net
pro
fit (,
000
Tk./h
a)
AC
Dry season shrimp
Improved rice (aman)-shrimp system
• Advancing the stocking of prawn can provide farm net returns of about 300% higher than is the case with the wet season rice crop that was currently practiced
Characteristics of different shrimp production systems that are presently being practiced in south-west region of Bangladesh (Adapted from Joffre et al., 2010)
Framing Characteristics
Shrimp monoculture Rice and shrimp rotation
Rice-aquaculture and shrimp
rotation
Extensive Semi-intensive
Pond size (ha) 1-40 1-2 1-5 1-5 Mean stocking rate (ind/m2)
1-3 5-15 1-3 1-3
Input use Lime, fertilizer Pellet feeds, water
treatment
Lime, fertilizer Lime, fertilizer
Yield (kg/ha) 10-380 (av. 242)
49-2067 (av. 1058)
Rice: 1000-3000 Shrimp: 73-268(av. 160)
Rice: 1000-3000 Fish: 10-50 Shrimp: 73-268 (av. 160)
Freshwater prawn (M. rosenbergii)
farming • Prawn aquaculture, which is widely adopted in Bagerhat
and Khulna districts.
• Spreading to other south and central coastal zones namely Jessore, Patuakhali and greater Noakhali districts (Abedin et al., 2000).
• Mostly practiced in an integrated manner with filter-feeding carps, paddy and growing of vegetables on the pond dyke.
• Integrated prawn-rice-fish-vegetables cycle begins in May/June, with stocking of prawn PL and fish fingerlings, followed by planting of boro rice in January (Williums and Khan, 2001; Azad et al., 2005).
Freshwater prawn (M. rosenbergii)
farming • Prawn aquaculture, which is widely adopted in Bagerhat
and Khulna districts.
• Spreading to other south and central coastal zones namely Jessore, Patuakhali and greater Noakhali districts (Abedin et al., 2000).
• Mostly practiced in an integrated manner with filter-feeding carps, paddy and growing of vegetables on the pond dyke.
• Integrated prawn-rice-fish-vegetables cycle begins in May/June, with stocking of prawn PL and fish fingerlings, followed by planting of boro rice in January (Williums and Khan, 2001; Azad et al., 2005).
• Techniques available for increased production by adoption of improved to semi-intensive farming system
• Approximately 20,000 ha are suitable for semi-intensive farming (BFFEA , 2001)
Modified closed system (Saha et al. 2006-07) • Stocking density 9-15/sqm; yield rate of 1250 – 1885 kg/ha
with FCR 1.4-1.6 and net return of Tk. 0.2 million/cycle Modified improved culture • Stocking density 5-9/sqm; yield rate 670-759 kg/ha with
2.15-2.4 and net return Tk. 0.07 – 0.15 million (Laif and Alam, 2008)
• Stocking density 5/sqm; yield rate 667-811 kg/ha (Saha et al., 2008)
Opportuni*es for increased produc*vity
Species diversification in shrimp farming
• Success in captive breeding and seed production of Mystus gulio, locally called “nona tengra” (Alam et al., 2006; Alam et al., 2007b).
• Shrimp-tilapia (GIFT/monosex) mixed and/or rotational (Alam et al., 2008; Saha et al., 2009)
• Shrimp-Pangas-tilapia polyculture (BFRI, 2007)
• Shrimp-mud crab biculture (Momtaz et al., 2007; Momtaz et al., 2010)
Opportuni*es for increased produc*vity
Environmental impact of shrimp farming
Two major environmental issues: are addressed: clearing of mangroves for farm development and coastal land degradation due to salinization.
Area Location Total area of mangrove (ha) Total loss (ha) 1975 1983 1999
South-west SRF 600,386 600,386 600,386 - South-east Chakaria 8,512 4,758 411 8,54
Maiskhali Island 1,645 n/a 2,773 290 Matabar Island 125 n/a 315 104 Jaliardwip Island 140 146 13 133 Naf River 667 n/a - 667
Total: 613,470 n/a 605,897 9,734
Loss of mangrove areas in Bangladesh aLributed to shrimp culture (Shahid and Islam, 2002)
• There are reports that shrimp farming is not solely responsible for increased soil salinity.
• Reduction in upstream freshwater flows, together with changes in siltation patterns and extensive groundwater extraction has had a much more profound effect on the salinity increase in coastal region (Huntington, 2003).
Environmental impact of shrimp farming
• Degraded soil qualities due to 5-15 years of
continuous shrimp farming in the areas were minimized with the beginning of present rice–shrimp rotation practices (Ali, 2006)
• Shrimp pond effluents impact on surrounding water quality is not yet a primary issue of concern (Bergheim et al., 2002).
• Biodiversity loss has been minimized through adequate supply of hatchery bred shrimp PL
• Water quality problem – mainly due to shallow (<60 cm) water depth.
Social impact of shrimp farming
• Literature available on social issues highlighting negative
social consequences : land and water use conflict, income inequality, displacement of small and marginal farmers, etc. (Ahmad,1996; Alauddin and Tisdell, 1998; Begum and Alam, 2000)
• Positive social benefits are also recognized : mobility and diversification of the sources of income, increased employment, greater household food security, education and health facilities, communication, etc (Begum and Alam, 2000; Pokrant and Bhuiyan, 2001)
• With the gradual but widespread increase in owner occupation, reduction in gher size and operation, paddy farmer vs shrimp farmers conflict has much been reduced Huttington, 2003).
Social impact of shrimp farming
• With the gradual but widespread increase in owner occupation, reduction in gher size and operation, paddy farmer vs shrimp farmers conflict has much been reduced Huttington, 2003).
Negative consequences (Ahmad,1996; Alauddin and Tisdell, 1998; Begum and Alam, 2000)
Positive consequences (Begum and Alam, 2000; Pokrant and Bhuiyan, 2001)
Land and water use conflict Income inequality Displacement of small and marginal farmers Violence, etc.
Mobility and diversification of the sources of income Increased employment Greater household food security Education and health facilities Communication, etc
Sectorial linkage and livelihoods
(Alauddin and Hamid, 1998).
More than 600,000 people iengaged in activities related to shrimp aquaculture (Alam and Phillips , 2004) ; 25% are women
Conclusion
• The future development challenge in brackishwater
aquaculture should focus on :
• Multidisciplinary empirical R&D to explore the development prospects of regulated shrimp cul t ivat ion protect ing environment and agriculture.
• Assessment of the carrying capacity of different areas of coastal zones for the production and shrimp and rice.
• Identification area/zone specific farming pattern.
Conclusion
• Improvement of land-water management system
are of prime importance to setting R&D strategies.
• Supply and value chain at each level of production and marketing for greater benefit of producers and consumers as well.
• Policy guidelines with flexibility to respond effectively to changes in different variables that determine success and failure of shrimp farming.