Monday , 26 July 2021

Farming Milkfish

Why MILKFISH?

  • Hatchery technology for large-scale seed production is already established
  • Easy to culture and can be grown in a wide range of environments
  • Innovations in culture practices based on research data and farmer’s experiences have been adopted by industry practitioners
  • An important food commodity in Southeast Asia

How to culture MILKFISH?

Milkfish breeder raised at SEAFDEC/AQD

Broodstock management

  • Milkfish takes about 3-5 years to attain sexual maturity and spawns under marine conditions.
  • Milkfish can be grown to broodstock size (about 3-5 kg) in earthen ponds, in marine net cages, or in tanks
  • For a start, about 100 juveniles can be stocked in a 1000 m2 pond, or 10 m diameter cage, or 200-ton tank.
  • Growing juvenile milkfish to broodstock size for 3-4 years in brackishwater ponds relying mostly on natural pond productivity and occasional supplemental feeding when needed is more cost-effective than growing them in tanks or marine cages.
  • Juveniles are given commercial feed twice a day at 2-3% of fish body weight until they reach broodstock size.
  • After 3 years or when stocks begin to mature, potential breeders in ponds should be transferred to either concrete tanks or marine net cages.
Milkfish fry in basins produced at SEAFDEC/AQD hatchery ready for transport to nursery ponds

Larval rearing

  • Clean the larval rearing tanks (LRT) with detergent and thoroughly rinse with fresh water.
  • Fill tanks to half the volume of LRT with filtered seawater a day before stocking the larvae to stabilize the condition of the rearing water.
  • Increase seawater level of the LRT daily following the protocol for water management (see Figure 1 below).
  • Add Nannochloropsis sp. at 300,000–500,000 cells/ml daily.
  • Feed larvae with enriched rotifers (Brachionus sp.). The feeding ration is adjusted according to the age of milkfish larvae until day 15. Following the feeding scheme in Figure 2 will minimize the volume of rotifer needed for feeding the larvae during the early stage. Consumption of rotifer during the early larval stages is low and gradually increases as the larvae grow. The ration is increased to 20 ind/ml of rotifers starting day 16 until harvest. Adjust feeding rations when the survival of fry is high or when the rotifer density in the afternoon decreases according to the suggested daily feeding ration.
  • Count the rotifer density in the morning and in the afternoon. If rotifer density falls below the desired ration add rotifer into the LRT.
  • Introduce larval diet starting day 8 at 1 g/ton/day and increase ration to 2-3 g/ton/day as the larvae grow.
  • Feeding should be done before 9 am to prevent starvation of the larvae/fry.
  • Siphon the water out of the tanks starting on day 6 to remove excess food and debris. Practice early feeding of larvae before siphoning is done. Siphon the water out of the tanks every other day to minimize stress to the larvae.
  • The rearing period of milkfish in the hatchery is 21-25 days. When the fry starts to swim in a circular motion inside the tank, this is an indication that the fry is ready for harvest.
  • Harvesting of fry is done early in the morning, 1-2 days before the scheduled transport to have enough time for the milkfish fry to rest before transport.

Minimum and maximum levels of different water parameters that should be observed during larval rearing

Water parameters Minimum Maximum
Temperature (°C) 28 32
Salinity (ppt) 28 33
Dissolved oxygen (mg/L) 4 Saturation
pH 6 8
Ammonia (mg/L) <0.02
Nitrite (mg/L) <0.01
Chlorine (mg/L) <0.02
Figure 1. Water and algae management of the culture water

 

Figure 2. Feeding management for milkfish larval rearing

 

Hand-feeding of milkfish in a grow-out cage

Cage culture operations

  • Cages must be set up in calm waters to protect them from strong winds and waves. Ideal areas are coves, sheltered lagoons, inlet bay, or behind an island with adequate water flow. The site must also be free from harmful pollutants.
  • Water depth should be at least 10 meters at the lowest low tide (ideally, 15-30 m) with good water exchange or flushing. The substrate of the site should be coarse or sandy and away from seagrass beds and coral reefs.
  • Stock 12,000 pieces fingerlings in a 10 m x 10 m x 4 m cage.
  • Hand-feed fingerlings at 8 am, 12 noon, and, 4 pm at the center of the cage (see table below for the feeding rates).
  • Change the nets once a month or as the need arises to allow efficient water exchange.
  • A partial harvest can be done when the fish reached the size of 400-500 grams.

Feeding rates

Fish weight (g) Rate (% of fish body weight)
5-50 10
51-125 8
125-199 6
200-250 5.5
251-300 5
300-400 4
400-500 3.5-3
>500 2.5

Suitable water quality for cage culture of milkfish

Parameters Range
pH 7.5-8.3
Dissolved oxygen 4-8 mg/l (ppm)
Water salinity 20-32 ppt
Water temperature 26-32°C
Ammonia nitrogen less than 0.02 mg/l
Water current 0.1 m/second

Is MILKFISH profitable?

Technical information in small-scale hatchery operations

Project duration (years) 10
Rearing tanks, cubic meters 10,000
Number of tanks 6
Stocking density, number of larvae per liter 15-25
Number of larvae stocked in all 6 tanks per run 1,200,000
Larvae requirement per year 12,000,000
Survival rate of larvae, % 50
Number of fry harvested per run 600,000
Number of runs per year 10
Number of fry produced per year 6,000,000
Selling price, PhP per fry 0.30

Cost and returns analysis of a small-scale hatchery operations

Quantity Unit Cost PhP/year
Sale of fry per year, PhP 0.30 per piece, 3% mortality allowance as discount 5,820,000 0.30 1,746,000
Variable cost
Larvae stocked per year, PhP 12,000 per million 12 12,000 144,000
Feeds, kg 750 10 7,500
Fertilizers, kg 600 10 6,000
Other supplies 700 10 7,000
Electricity, 720 kwh/run, 10 runs/year 7,200 10 72,000
Fuel, 100 liters/month, PhP 50/liter 1,200 50 60,000
Labor
          1 technician, PhP 10,000/month, 13 months 13 10,000 130,000
          1 hatchery aide, PhP 10,000/month, 13 months 13 6,000 78,000
Harvest expenses @ PhP .01/fry 60,000
Maintenance, 2% of equipment 7,500
Consumable materials, plankton nets, filter bags 5,000
Subtotal 577,000
Fixed cost  
Rent on land, PhP 1,500/month 12 1,500 18,000
Depreciation 149,600
Management overhead,
PhP 10,000/month, 13 months
13 10,000 130,000
Business permit 5,000
Interest on loans to fund half of capital investment cost & all variable cost,
12% per annum, 12 months term
120,300
Opportunity cost of capital, 2.5% interest rate per annum 10,638
Subtotal 433,538
TOTAL COST 1,010,538
Net income per year 711,943
ROI % 86%
Payback period 0.96
Unit cost (PhP/fry) 0.17

Technical information for 1-cage and 4-cage operation

Project duration (years) 5
Culture period (days; 120-150, average=135) 135
Cage size (10 m x 10 m x 5 m) 500
Stocking density (pcs/m3) 30
Number of fingerlings stocked per cage (pcs) 15,000
Number of fingerlings stocked in 4 cages (pcs) 60,000
Survival rate (%) 95
Number of milkfish at harvest per crop per cage (pcs) 14,250
Size at harvest (g) 440
Volume of harvest per crop (kg) 6,270
Number of cages 4
Volume of harvest from 4 cages, 1 crop (kg) 25,080
Number of crops per year 2
Volume of harvest from 4 cages per year (kg) 50,160
Farm-gate selling price of milkfish (400 g per piece) 90

Costs-and-returns analysis of monoculture of milkfish in 1-cage and 4-cage operation

Price/unit
(PhP)
Units/
cage/
run
1-cage Operation 4-cage Operation
PhP/cage/
run
PhP/year PhP/cage/
run
PhP/run PhP/year
Revenue
Gross sales, milkfish, 400 g per piece 90 6,270 564,300 1,128,600 564,300 2,257,200 4,514,400
Costs
A. Variable costs
Milkfish fingerlings 6 15,000 90,000 180,000 90,000 360,000 720,000
Feeds (starter), 25 kg/sack 617 51 31,467 62,934 30,837 123,350.64 246,701
Feeds (grower), 25 kg/sack 732 192 140,544 281,088 137,733 550,932 1,101,864
Feeds (finisher), 25 kg/sack, FCR=2.2 725 308 223,300 446,600 218,834 875,336 1,750,672
Harvesting cost 3,000 1 3,000 6,000 3,000 12,000 24,000
1 operator for 1 cage (1 hired aide + 1 operator
for 4 cages) PhP 4,000/month each, 13
months
4,000 13 26,000 52,000 13,000 52,000 104,000
Maintenance and repairs (3% of investment
costs per year if 1 cage, 2% if 4 cages)
2,220 4,440 1,437.75 5,751 11,502
Total variable costs 516,531 1,033,062 494,843 1,979,370 3,958,740
B. Fixed Cost
Depreciation costs 24,200 48,400 23,660 94,640 189,280
Business license & other permits, 4 cages,
PhP 5000/year
1,500 3,000 375 1,500 3,000
Interest on loans to variable cost, 12% per
annum, 4.5 months loan per term
11,622 23,244 11,134 44,536 89,072
Opportunity cost of own capital, 0.5- 2.5%
interest/annum
370 740 1,797 7,189 14,378
Total fixed costs 37,692 75,384 36,966 147,865 295,729
TOTAL COSTS 554,223 1,108,446 531,809 2,127,235 4,254,469
Net income (PhP) = (gross revenue-total costs) 10,077 20,154 32,491 129,965 259,930
ROI (%) = (net income/investment cost) x 100 13.6% 45.2%
Payback period (years) = investment cost/(annual
net income + annual depreciation)
2.16 1.28
Unit variable cost 82.38 78.92
Break-even price (PhP/kg) = annual total cost/
annual production
88.39 84.82
Break-even production (kg) = total cost/selling
price
12,316 47,271.88

Note: 2% discount on feed cost on bulk buying

Need ASSISTANCE?

Watch related videos!

Milkfish Fry Collection, Handling, and Transport (Part 1)

Milkfish Fry Collection, Handling, and Transport (Part 2)

Milkfish Fry Sufficiency

Get a copy of our manuals!

AEM 58_thumbnail AEM 58 Milkfish Chanos chanos cage culture operations (2014) 39 pp
Albert gaitan et al
A 39-pages extension manual describing the biology, fingerling production, site selection, cage design and construction, measurement & analysis of water & sediment quality parameters, and economics.
AEM 62 milkfish broodstock thumbnail  AEM 62 Development and Management of Milkfish Broodstock (2015) 33 pp
Ofelia S. Reyes et al
A 33-page manual detailing the methods/procedures in managing milkfish broodstock
aem63_seed production of milkfish thumbnail AEM 63 Seed Production of Milkfish Chanos chanos Forsskal (2016) 26 pp
Ofelia Reyes, Bernardita Eullaran, Evelyn Grace Ayson
A 26-page manual describing the site selection, hatchery design, spawning, larval rearing, natural food production, and economic analysis for milkfish.

Check out our online bookstore for more titles: www.seafdec.org.ph/bookstore

Attend our hands-on training!

Marine fish hatchery operations training course at SEAFDEC/AQD’s Tigbauan Main Station.

To apply, kindly contact:

Training and Information Division
(63-33) 330 7030
training@seafdec.org.ph

Check out our training schedule: www.seafdec.org.ph/training

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