Aquaculture production systems in intertidal areas of Bangladesh: A review

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Aquaculture production systems in intertidal areas of Bangladesh: a review Md. Jahangir Alam Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur-1706, Bangladesh

description

By Md. Jahangir Alam Revitalizing the Ganges Coastal Zone Conference 21-23 October 2014, Dhaka, Bangladesh http://waterandfood.org/ganges-conference/

Transcript of Aquaculture production systems in intertidal areas of Bangladesh: A review

Page 1: Aquaculture production systems in intertidal areas of Bangladesh: A review

Aquaculture production systems in intertidal areas of

Bangladesh: a review

Md. Jahangir Alam Bangabandhu Sheikh Mujibur Rahman Agricultural University

Gazipur-1706, Bangladesh

Page 2: Aquaculture production systems in intertidal areas of Bangladesh: A review

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  

Page 3: Aquaculture production systems in intertidal areas of Bangladesh: A review

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)

Page 4: Aquaculture production systems in intertidal areas of Bangladesh: A review

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).

Page 5: Aquaculture production systems in intertidal areas of Bangladesh: A review

•  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

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•  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)  

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•  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  

Page 8: Aquaculture production systems in intertidal areas of Bangladesh: A review

•  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  

Page 9: Aquaculture production systems in intertidal areas of Bangladesh: A review

•  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  

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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  

 

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   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

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   Shrimp-­‐rice  produc*on  system  

 

Modified  ader  DaLa,  2001  

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   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)  

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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)  

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   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)  

Page 16: Aquaculture production systems in intertidal areas of Bangladesh: A review

   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.

Page 17: Aquaculture production systems in intertidal areas of Bangladesh: A review

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

Page 18: Aquaculture production systems in intertidal areas of Bangladesh: A review

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

Page 19: Aquaculture production systems in intertidal areas of Bangladesh: A review

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)

Page 20: Aquaculture production systems in intertidal areas of Bangladesh: A review

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).

Page 21: Aquaculture production systems in intertidal areas of Bangladesh: A review

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).

Page 22: Aquaculture production systems in intertidal areas of Bangladesh: A review

•  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    

Page 23: Aquaculture production systems in intertidal areas of Bangladesh: A review

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  

Page 24: Aquaculture production systems in intertidal areas of Bangladesh: A review

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).

Page 25: Aquaculture production systems in intertidal areas of Bangladesh: A review

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.

Page 26: Aquaculture production systems in intertidal areas of Bangladesh: A review

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).

Page 27: Aquaculture production systems in intertidal areas of Bangladesh: A review

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  

Page 28: Aquaculture production systems in intertidal areas of Bangladesh: A review

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

Page 29: Aquaculture production systems in intertidal areas of Bangladesh: A review

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.

Page 30: Aquaculture production systems in intertidal areas of Bangladesh: A review

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.