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Technology Description Brief description: Seabass is a species that is easy to culture in cages or in brackishwater ponds. It is hardy, and the seedstock can be easily sourced from the hatchery. There is a need, however, to include a nursery before the grow-out phase so that seabass can be easily sorted and size-graded to reduce competition for space and food, thus controlling cannibalism. Survival in the 30-45 day nursery phase can be as high as 96%. The biggest expense for seabass culture is feeds, as the fish is carnivorous and must be fed trash fish. But there are already available high-protein formulated feeds that can be used like SEAFDEC/AQD’s formulation for carnivorous species. And, other than |
the regular sorting and size-grading, seabass culture is pretty straightforward.
(1) Stock seabass fry obtained from the hatchery in nursery cages set inside brackishwater ponds or in an estuary (mouth of the river). The netcage size may be 3 x 2 x 1.3 m, and 600-900 pieces may be stocked. Take care to stock similar-sized fish already sorted and size-graded from the hatchery. Initial fry size is usually 1.0 to 2.5 cm, and the fry stays in the
nursery for 30 to 45 days. Fed trash fish at 6-8% of biomass or use formulated feeds as recommended by the manufacturer. Sort and size-grade weekly.
(2) Transfer seabass to grow-out ponds or to grow-out cages. Stocking density is usually 40-50 fish per m2 which is reduced to 10-20 fish per m2 when seabass are bigger. A 1-ha pond may be subdivided further into six compartments so that there is space to raise different batches of sorted and size-graded fish. A grow-out cage is bigger than nursery cages, about 4 x 4 x 3 m. Be sure to have spare cages.
(3) Feed trash fish, at 10% of total body weight.
(4) Sort and size-grade regularly. In the pond, collect fish by using a net seine; in cages, simply lift the nets. Take care not to stress the fish.
(5) Culture period varies, but is usually 3-4 months. The market size of seabass is 300-400 grams.
Investment Cost
P321,200 for two units of 4 x 4 x 3 m cages; P337,680 for a 1-ha pond
Expected Returns
a. Expected gross revenues (one year): P691,200 for cages; P720,000 for pond
b. Internal Rate of Return (IRR) (10% discount rate, 5 years): 99% for cage, 84% for pond
c. Return on Investment (year 1): 26.46% for cage, 23.34% for pond
d. Net Present Value (NPV) (10% discount rate, 5 years): P199,332 for cage, P165,539 for pond
e. Benefit Cost Ratio (BCR): 1.14 for cage, 1.12 for pond
|
Item |
Cages |
Ponds |
|
Revenues |
691,200 |
720,000 |
|
Less: |
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|
Variable cost |
||
|
Fingerlings |
144,000 |
150,000 |
|
Feeds |
284,160 |
296,000 |
|
Wages |
48,000 |
25,800 |
|
Fuel |
26,400 |
|
|
Subtotal |
476,160 |
498,200 |
|
Fixed cost |
||
|
Depreciation |
16,624 |
17,712 |
|
Permit fee |
2,000 |
0 |
|
Land rent |
0 |
10,000 |
|
Management fee |
36,000 |
36,000 |
|
Maintenance and repairs |
8,312 |
8,856 |
|
Interest |
67,114 |
70,411 |
|
Subtotal |
130,050 |
142,979 |
|
Total cost |
606,210 |
641,179 |
|
Net income |
84,990 |
78,821 |
Feed Development Section. 1994. Feeds and feeding of milkfish, Nile tilapia, Asian sea bass, and tiger shrimp. Aquaculture Extension Manual 21. SEAFDEC Aquaculture Department, Tigbauan, Iloilo. 97 p
SEAFDEC Asian Aquaculture, volume 19, number 4, October 1997. SEAFDEC/AQD, Tigbauan, Iloilo. Special issue, pages 13-29
© 2008 SEAFDEC Aquaculture Department
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