bringing back seasonality into coastal aquatic agricultural systems
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By Kazi Ahmed Kabir, S.B. Saha, Manjurul Karim, Craig A. Meisner, Michael J. Phillips Revitalizing the Ganges Coastal Zone Conference 21-23 October 2014, Dhaka, Bangladesh http://waterandfood.org/ganges-conference/TRANSCRIPT
Bringing back seasonality into coastal aqua3c agricultural systems:
shi$ing from shrimp monoculture to more produc3ve, diversified and resilient systems
BANGLADESH
Salinity fluctuates from high in dry season to medium in rainy season
Research site
Research Questions:
1. Can brackishwater aquaculture system produc9vity be increased? 2. What species combina9on is more suitable for increased produc9vity, profitability and resilience in year-‐round brackishwater areas? 3. What are the costs and benefits of monoculture versus polyculture?
4
Before
Construc3on
Ponds Pond
Aquaculture Treatments in 2012
3 treatments with 4 replications:
1. Farmer’s mgt: Polyculture, shrimp+ different fish sp
2. Improved mgt1: Rotational Monoculture, shrimp-tilapia-prawn (Cycle 1, 2 & 3)
3. Improved mgt 2: Rotational Polyculture, shrimp+tilapia – tilapia+tengra - prawn+tengra( Cycle 1, 2 & 3)
Tilapia + CaEish
Prawn (fresh water) Shrimp (brackish water)
Aquaculture Treatments in 2013
3 treatments with 4 replications:
1. Farmers’ mgt : Polyculture Shrimp+ several fish spp, multiple stockings & harvests
2. Improved mgt 1: Rotational monoculture Dry season - shrimp (2 crops) (Cycle 1 & 2)
Wet season - tilapia (Cycle 3)
3. Improved mgt 2: Rotational polyculture Dry season - shrimp+tilapia (2 crops) (Cycle 1 & 2)
Wet season - polyculture rohu + singh + magur (Cycle 3)
Carp
Singh & Magur
Shrimp
Nona tengra
Tilapia
……………Dry season…………………… ……………….Wet season……………………………………………………………
CaFish (3 spp)
Aquaculture treatments (4 reps)
Treatm
ents
Cultu
re
paLerns
2012 2013
Cycle 1 Cycle 2 Cycle 3 Cycle 1 Cycle 2 Cycle 3
Farmer’s prac3ce Poly
Shrimp + different sp of fish (mul3ple stocking &
harves3ng)
Shrimp + different sp of fish (mul3ple stocking &
harves3ng)
Improved prac3ce 1 Mono Shrimp Tilapia
Prawn
Shrimp Shrimp
Tilapia
Improved prac3ce 2
Poly Shrimp
Tilapia Tilapia Tengra
Prawn Tengra
Shrimp Tilapia
Shrimp Tilapia
Rohu Singh Magur
Managed by farmers
Management
Prac3ce Farmer’s Prac3ce
Improved 1 & 2
Liming 200 kg ha-‐1 200 kg ha-‐1
Water filtering Unfiltered Filtered Predatory Fish No control Controlled Disinfec3on No disinfec9on Disinfected Fer3liza3on No fer9lizer Fer9lizer & dolomite Shrimp seed Not PCR tested PCR tested Feed No feed Feeding Water replenishment When needed When needed Post stocking fer3liza3on Very insufficient When primary
produc9on is low Fish seed Some wild All from hatcheries
Timeline 2012
Shrimp & fish Stocking 1 Shrimp
disease in some ponds
Harvest 3
April March Aug. Dec.
Harvest 2
Sept.
Stocking 3 Harvest 1 & Stocking 2
June July Nov. May Oct.
Dry season Wet season
Timeline 2013
Shrimp & fish Stocking 1
Rice harvest
April March Aug. Dec.
Harvest 2
Harvest 3
Sept.
Harvest 1 Stocking 2
May July Nov.
Stocking 3
Dry season Wet season
Water Depth (2012 versus 2013)
2012
2013
30 40 50 60 70 80 90
100 110
1 15
28
42
56
70
84
98
112
126
140
154
168
182
196
210
224
238
252
266
280
Depth (cm)
7 March
Farmer's prac3ce Monoculture Polyculture
20 30 40 50 60 70 80 90 100
1 14
28
42
56
70
84
98
112
126
140
154
168
182
196
210
224
238
252
Depth (cm)
Days of culture 14 M
arch
Farmer's prac3ce Monoculture Polyculture
Cycle 1
Cycle 2
Cycle 3
Cycle 1
Cycle 2
Cycle 3
Water Salinity (2012 versus 2013)
2012
2013
Cycle 1
Cycle 2 Cycle 3
0
5
10
15
20
25
1 15
28
42
56
70
84
98
112
126
140
154
168
182
196
210
224
238
252
266
280
Salin
ity (p
pt)
7 March
Farmer's prac3ce
Monoculture
Polyculture
0
5
10
15
20
25
1 14
28
42
56
70
84
98
112
126
140
154
168
182
196
210
224
238
252
Salin
ity (p
pt)
Days of Culture 14 M
arch
Farmer's prac3ce Monoculture Polyculture
Cycle 1 Cycle 2
Cycle 3
Results
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Farmer's prac3ce Monoculture Polyculture
Yield (kg ha
-‐1) Shrimp
Fish
2012
a
b c a
b
c
0
500
1000
1500
2000
2500
3000
3500
4000
Farmer's prac3ce Monoculture Polyculture
Yield (kg ha
-‐1) Shrimp
Fish
2013
a
b c a
b c
(1) System produc3vity -‐ annual Produc3on (kg/ha) in 2012 & 2013
2012
Culture patterns
Cycle-1 (91 days)
Cycle-2 (71days)
Cycle-3 (100 days) Total
Shrimp Tilapia Tilapia Tengra Prawn Tengra Shrimp Fish
Farmer’s practice
278 days *209.84a 728.14a
Mono 197.77 -‐ 2367.48 -‐
363.63
-‐ 556.40b 2367.48b
Poly 172.64 1163.41 1519.78
352.34
231.74 286.50 404.38c 3322.04c
2013
Culture patterns
Cycle-1 (70 days)
Cycle-2 (50 days)
Cycle-3 (99 days) Total
Shrimp Tilapia Shrimp Tilapia Magur+ singh
Tilapia/ rohu Shrimp Fish
Farmer’s practice
259 days 390.05a 659.41a
Mono 565.62 -‐ 291.77 - - *3307.71 857.39b 3307.71b
Poly 373.64 1744.45 193.19 777.90 557.63 **480.05 566.83c 3560.02c
Cycle-‐wise produc3on (kg/ha) in 2012 & 2013
Fish Category 2012** 2013** Remarks
Tengra-‐Tilapia 41654.38a -‐ Risk free; Less profit -‐ Tengra may escape if dikes are not good
Tengra -‐Prawn 116000b
-‐ Depends on availability of prawn Juvenile; -‐ Tengra may escape if the dikes are not good
Carp-‐Singh-‐Magur 147816.11c
-‐ Singh & Magur culture depends on rainfall -‐ Singh & Magur may escape if the dikes are not good
Shrimp-‐Tilapia 101450.71b 128000b -‐Shrimp risky but 9lapia provides the back up
(2) Species combina3ons -‐ gross margin (BDT/per cycle/ha) from different polyculture species composi3on
(3) Polyculture vs monoculture
-‐100
0
100
200
300
400
500
600
700
Farmer's prac3ce Monoculture Polyculture
BDT 1000 ha-‐
1
Variable cost Total return Gross margin
2012
a
b
c
-‐100
0
100
200
300
400
500
600
700
800
Farmer's prac3ce Monoculture Polyculture
BDT1000 ha
-‐1
Variable cost Total return Gross margin
2013
a
b b
Cost, return, gross margin
(including farmer’s labor & land leasing value)
Ponds Species Total cost (BDT/ha)
Produc3on (kg/ha)
Sale (BDT/ha)
Gross return (BDT/ha)
3 Shrimp
212240 515.97 257985 297985
Tilapia 2557.58 281333.8 281356
8 Shrimp
182147
349.26 174630 174630
Tilapia 2079.62 228758.2 228758
6 Shrimp
157900 0 0 0
Tilapia 1930.79 193079 193079
11 Shrimp
157137 0 0 0
Tilapia 1920.71 192071 192078
Impact of crop diversifica3on in shrimp ghers (Shrimp – 3/m2 & 3lapia 2/m2, culture period – 91 DOC)
Promising opportuni3es for scaling ! 275,000 ha of all year-‐round saline aquaculture area ! G2 extension farmers involved par9cipatory adop9on trial and sharing with other farmers
! Implemen9ng community water management for brackishwater aquaculture with BRAC
! Extension materials prepared and disseminated
Key implementa3on challenges Markets systems • Access to quality shrimp and fish seed • Access to quality feed in local market
Aquaculture management • Maintaining water depth • Preven3on of escaping cat fish through dikes • Aqua3c weed control
Community • Poor feeder canal for gravita3onal water exchange (need community level management – common theme!)
• Poaching risk
Conclusion
q Significant improvements in produc3vity and income through a diversified culture system under beLer management prac3ces.
q Shrimp-‐3lapia polyculture system profitable with greater resilience compared to other species combina3ons. Risks of shrimp can be recovered by return from Nile 3lapia
q Polyculture and alternate cropping monoculture more profitable than current prac3ces. Gross margin from polyculture higher than monoculture
Lesson learned q Considerable opportuni3es exist for improving
aquaculture in the coastal “year-‐round” saline zone.
q Technologies appear to be very “adoptable” by farmers
q Community water management can further improve op3ons for aquaculture and risk management
q Possible to integrate vegetable produc3on from dikes in wet season and support livestock food by growing saline tolerant grass on the dikes
q Saline water represents an asset….
Aquaculture production must more than double by 2050 to satisfy projected fish demand Million tons
Sources: Produc9on data 1961–2010: FAO (2014a), FAO (2014b). Aquaculture produc9on projec9ons 2011–2050: Authors’ calcula9ons assuming a linear growth rate of 2 Mt per year.
Project aquaculture production …. South Asia is a hotspot for future fish demand
• S. Asia – from 2.2 to 4.4 mt • India – from 3.9 to 8.6 mt