Brackishwater Pond Culture of Black Tiger Shrimp (Prawn)

This new technology on shrimp farming in brackishwater ponds incorporates pollution management which constitutes 9% of annual shrimp production cost per ha of the farmer. Pollution management is worth the cost considering that a shrimp farmer could lose it all during a disease outbreak.

Environment-friendly practices include:

(1) Lowered stocking density – this may decrease harvest volume by 20-30% but the harvest value could increase by 8-10%due to bigger size and improved feed conversion. Feeding and nutrient loading is reduced by 20%, and the risk of opportunistic diseases is reduced as well.

(2) Improvement of pond bottom management – this may increase plowing or tilling cost, add netcage construction to the expense but these costs could be recovered from the sale of added fish crop. Bacterial profile of sediment is improved, however, as well as water effluent quality. The pathogenic Vibrio count is reduced.

(3) Crop rotation – one shrimp crop may be lost but there is some income from fish culture. Crop rotation improves sediment bacterial profile, reduces Vibrio count, reduces incidence of white spot, and ultimately allow time for organic waste to break down.

(4) Improvement in feed quality – SEAFDEC/AQD has formulated a diet much improved in nutritional quality and lower nitrogen and phosphorus discharges. Farmers may also use probiotics.

(5) Stocking of laboratory-screened fry – there is a cost to fry analysis and screening and waiting time for the results, but the farmer is reducing the risks for white spot and pathogenic Vibrio infections.

(6) Use of greenwater technology – culture area may be reduced by 25-50% due to the requirement for bigger reservoir but cost can be recovered from the sale of fishes raised in the reservoir. There is also added expense for modifying the water supply channel. The advantage is more stable water quality, and suppression of growth of pathogenic Vibrio.

(7) Use of probiotics in water and feed – this can add a cost of P20,000 to P40,000 per ha per crop but healthy, antibiotic-free shrimp is produced. Improved water quality and lower sludge accumulation are the benefits, in addition to reducing the risk of developing more virulent antibiotic-resistant strains of bacteria.

(8) Increase in aeration – addition of P150,000 to 200,000 per ha for aerators and 50-60% increase in power consumption but the shrimp grow faster and improve its feed conversion with increased dissolved oxygen levels and reduced noxious metabolites.

(9) Use of settling ponds – additional cost of P2,500 to 5,000 per ha per year but settling ponds lower load of suspended solids in effluent water and reduce the sediment accumulation in receiving waters.

(10) Employment of biosecurity measures – additional cost of P15,000 to 20,000 per ha per year for pond sanitation, carrier exclusion devices, filters, and worker hygiene but these measures significantly reduce the risk of introducing viral diseases to the pond facility.

Technology profile:

(1) Re-engineer the farm layout by providing a bigger reservoir; impounding a portion of the mangrove area near the ponds to where effluents may be held; and assigning sedimentation and biological treatment ponds containing fish, bivalves and seaweeds.

(2) Prepare the ponds. Drain totally. Level the pond bottom. Dig peripheral and central canals. Crack-dry. Remove the black sludge that accumulated in previous cropping. Flush the pond with water then drain. Apply either agricultural lime at 2 tons per ha or hydrated lime at 0.5 to 1 ton per ha. Till the pond bottom. Compact. Install the central and side sludge collectors. Install catwalks and feeding trays in grow-out ponds. Let in water. Position the aerators and the pumps. Apply teaseed powder at 50 kg per ha to kill predators and competitors. Apply dried chicken or cow manure at 300 kg per ha together with urea (45-0-0) at 18 kg per ha by the “tea bag” method. Fertilize again if necessary.

(3) In the reservoir (25% of the grow-out farm), stock biomanipulators like all-male tilapia and milkfish at 5,000 to 10,000 fish per ha. Hold water for at least a week before using it in grow-out ponds.

(4) In the grow-out ponds, acclimate then stock disease-free shrimp (at least postlarvae day 18) at 25 pieces per m2, which gives the highest net profit per ha of P1.8 million. Stocking lower at 15 pieces per m2 can get you P1.1 million; while stocking higher at 40 pieces per m2 gives only P0.6 million. Biomanipulators may be stocked inside walled net enclosures (10 x 10 x 1.5 m) that are placed in the middle of the grow-out ponds. These fishes can feed on the sludge that the paddle-wheel aerators tend to deposit at the center. The sides of the ponds may also be enclosed similarly and stocked with biomanipulators.

(5) Follow the usual pond routine – feed according to the feed manufacturer’s instructions, sample stock regularly to adjust feeding demand, monitor water quality and bacterial populations regularly, keep complete records. If probiotics is an option, follow the application rate in the label. Operate the aerators from 6 pm to 6 am.

(6) In the low discharge system, a small amount of water is discharged from the grow-out pond and released to the sea after passing through the settling or mangrove impoundment. To be effective, hold pond effluents in mangroves for 6 hours or more.

(7) In the recirculating system, effluents from the grow-out pond are reused after passing through the treatment pond. Water is fully circulated by pumping twice, first from the head reservoir to the grow-out pond and then from the treatment pond to the grow-out pond.

(8) In treatment ponds, the effluent from the grow-out ponds passes through several hurdles. Note that the main drain canal can serve as one of the treatment ponds. Install baffles to serve as mechanical filtration units and to settle suspended solids. Dissolved nutrients can be taken up by biofilters like oysters, the seaweed Gracilaria, and green mussel, and these are stocked in the treatment ponds. Finally, a filter box fitted with a 2 hp submersible pump is installed at the end of the pond.

(9) Harvest in 4-5 months by totally draining the ponds. Chill and sort before packing shrimp. Average weight is at least 25 grams.

Technical Assumptions

Item Without Biosecurity With Biosecurity
Project duration (years)
Production area (ha)
No. of crops /year
Days of culture /crop
Stocking density (fry/ha)
Biomanipulators stocking density (fry/ha)
Survival rate of shrimp (%)
Survival rate of biomanipulators (%)
Ave. body weight of shrimp at harvest (g)
FCR of shrimp
Production of shrimp per ha per crop (kg)
Production of shrimp per year (kg)
Farmgate price of shrimp (P/kg)
Production of biomanipulators/year (kg/yr)
Farmgate price of biomanipulators (P/kg)
5
1
2
150
250,000
6,000
40
60
30
2
3,000
6,000
300
540
50
5
1
2
150
250,000
6,000
70
60
30
1.7
5,250
10,500
300
540
50

Investment

Capital Outlay Without Biosecurity With Biosecurity Life Span
(Years)
Farm facilities
Pond dikes, gates and dikes
Biosecurity
Equipment
Annual depreciation cost/yr
Salvage value (10%)
Total investment cost
12,000
190,000

248,000
108,600
178,500
450,000
12,000
190,000
182,000
248,000
1,814,000
178,500
632,000
6
5-10
5
10


Cost and Returns

Item Description Without Biosecurity With Biosecurity
Variable Cost
Pond preparation
Fry
Feed and Feed Additives
Laboratory Analysis
Electricity and Fuel
Biosecurity
Biomanipulators
Labor
Harvest
Total Variable Cost
67,600
125,000
660,000
20,000
52,000

16,000
30,000
8,000
978,600
76,800
125,000
1,043,250
20,000
80,000
160,000
16,000
32,000
14,000
1,567,050
Fixed Cost (per year)
Land rental
Repair and Maintenance
Salary and Wages
Depreciation
Interest (12 %)
Total Fixed Cost
Total Cost

50,000
120,000
108,600
33,432
312,032
1,290,632

50,000
168,000
181,400
47,928
447,328
2,014,378
Revenue
Sale of shrimp
Sale of tilapia
Sale of milkfish
Total Sales
1,800,000
27,000
27,000
1,854,000
3,150,000
27,000
27,000
3,204,000

Economic Indicators

Item Description Without Biosecurity With Biosecurity
Income per year
ROI (%)
Payback period
Break-even price
Break-even production
563,368
43.65%
2.09
215.1
1,040.11
1,189,622
59.06%
1.57
191.85
6,714.59

Financial Investment Analysis (after 5 years)

Item Description Without Biosecurity With Biosecurity
Gross Revenue
Investment Cost
Total Cost
Net Income
Net Present Value @ 12% (NPV)
IRR (%)
Discounted BCR (Cost & Return Benefits)
9,448,500
(450,000@Y°)
6,453,160
2,995,340
1,501,876
124
4.74
16,198,500
(632,000@Y°)
10,071,890
5,494,610
3,355,006
188
6.95

For more information, contact:

SEAFDEC Aquaculture Department
Tigbauan 5021, Iloilo
Trunkline connecting all offices: (033) 3362965, 5119170 to 71
Fax: (033) 3351008
Email: [email protected]
Web: www.seafdec.org.ph

Note: Original article were sourced from www.seafdec.org.ph, re-posted on this site with permission.

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