17
Jan
2020

Small-scale Milkfish Aquaculture Technologies

Why MILKFISH

Milkfish (Chanos chanos) is a popular choice for aquaculture for several reasons, particularly in regions with suitable environmental conditions. Here are some reasons why milkfish is often selected for fish farming:

  1. Cultural and Culinary Significance:
    • Milkfish is a staple in the diets of many cultures in Southeast Asia and the Pacific Islands. It holds cultural significance and is widely used in traditional dishes.
  2. Adaptability:
    • Milkfish can tolerate a wide range of salinities, allowing for aquaculture in both freshwater and brackish water environments. This adaptability makes it suitable for farming in coastal areas and estuaries.
  3. Rapid Growth:
    • Milkfish is known for its fast growth rate, and under optimal conditions, it can reach marketable size in a relatively short time, typically 6-12 months.
  4. Feed Efficiency:
    • Milkfish has good feed conversion rates, meaning it efficiently converts feed into body mass. This contributes to its economic viability as an aquaculture species.
  5. Omnivorous Diet:
    • Milkfish is omnivorous and can be fed a variety of diets, including formulated pellets, natural feed, and agricultural by-products. This flexibility in diet makes it cost-effective to raise.
  6. Co-Culture Potential:
    • Milkfish is often raised in co-culture systems with shrimp or other species. This can enhance overall farm productivity and resource utilization.
  7. Market Demand:
    • In regions where milkfish is a dietary staple, there is a consistent and high demand for this fish. Its mild flavor and versatility in cooking make it popular among consumers.
  8. Environmental Benefits:
    • Milkfish farming can contribute to environmental sustainability by utilizing ponds or areas that are not suitable for other types of agriculture.
  9. Resilience to Handling:
    • Milkfish is relatively hardy and can tolerate handling and transportation, which is beneficial for the aquaculture supply chain.
  10. Potential for Intensive Systems:
    • Milkfish can be raised in intensive aquaculture systems, such as ponds and cages, allowing for efficient use of space and resources.
  11. Nutritional Value:
    • Milkfish is a good source of protein and essential nutrients, making it a nutritious food choice for consumers.
  12. Breeding and Hatchery Technology:
    • Advances in milkfish breeding and hatchery technology have improved the availability of high-quality fingerlings, supporting the development of commercial aquaculture.

While milkfish has numerous advantages, successful farming requires careful consideration of water quality, feeding practices, disease management, and compliance with local regulations. Farmers should also adopt sustainable and responsible aquaculture practices to ensure the long-term viability of milkfish farming operations.

How to culture MILKFISH?

milkfish breeder
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
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 parametersMinimumMaximum
Temperature (°C)2832
Salinity (ppt)2833
Dissolved oxygen (mg/L)4Saturation
pH68
Ammonia (mg/L)<0.02
Nitrite (mg/L)<0.01
Chlorine (mg/L)<0.02
Small-scale Milkfish Aquaculture Technologies 1
Figure 1. Water and algae management of the culture water
Small-scale Milkfish Aquaculture Technologies 2
Figure 2. Feeding management for milkfish larval rearing

 

milkfish grow-out cage
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)
5-5010
51-1258
125-1996
200-2505.5
251-3005
300-4004
400-5003.5-3
>5002.5

Suitable water quality for cage culture of milkfish

ParametersRange
pH7.5-8.3
Dissolved oxygen4-8 mg/l (ppm)
Water salinity20-32 ppt
Water temperature26-32°C
Ammonia nitrogenless than 0.02 mg/l
Water current0.1 m/second

Is MILKFISH profitable?

Technical information in small-scale hatchery operations

Project duration (years)10
Rearing tanks, cubic meters10,000
Number of tanks6
Stocking density, number of larvae per liter15-25
Number of larvae stocked in all 6 tanks per run1,200,000
Larvae requirement per year12,000,000
Survival rate of larvae, %50
Number of fry harvested per run600,000
Number of runs per year10
Number of fry produced per year6,000,000
Selling price, PhP per fry0.30

Cost and returns analysis of a small-scale hatchery operations (as of 2016)

QuantityUnit CostPhP/year
Sale of fry per year, PhP 0.30 per piece, 3% mortality allowance as discount5,820,0000.301,746,000
Variable cost
Larvae stocked per year, PhP 12,000 per million1212,000144,000
Feeds, kg750107,500
Fertilizers, kg600106,000
Other supplies700107,000
Electricity, 720 kwh/run, 10 runs/year7,2001072,000
Fuel, 100 liters/month, PhP 50/liter1,2005060,000
Labor
          1 technician, PhP 10,000/month, 13 months1310,000130,000
          1 hatchery aide, PhP 10,000/month, 13 months136,00078,000
Harvest expenses @ PhP .01/fry60,000
Maintenance, 2% of equipment7,500
Consumable materials, plankton nets, filter bags5,000
Subtotal577,000
Fixed cost 
Rent on land, PhP 1,500/month121,50018,000
Depreciation149,600
Management overhead,
PhP 10,000/month, 13 months
1310,000130,000
Business permit5,000
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 annum10,638
Subtotal433,538
TOTAL COST1,010,538
Net income per year711,943
ROI %86%
Payback period0.96
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 cages4
Volume of harvest from 4 cages, 1 crop (kg)25,080
Number of crops per year2
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 (as of 2014)

Price/unit
(PhP)
Units/
cage/
run
1-cage Operation4-cage Operation
PhP/cage/
run
PhP/yearPhP/cage/
run
PhP/runPhP/year
Revenue
Gross sales, milkfish, 400 g per piece906,270564,3001,128,600564,3002,257,2004,514,400
Costs
A. Variable costs
Milkfish fingerlings615,00090,000180,00090,000360,000720,000
Feeds (starter), 25 kg/sack6175131,46762,93430,837123,350.64246,701
Feeds (grower), 25 kg/sack732192140,544281,088137,733550,9321,101,864
Feeds (finisher), 25 kg/sack, FCR=2.2725308223,300446,600218,834875,3361,750,672
Harvesting cost3,00013,0006,0003,00012,00024,000
1 operator for 1 cage (1 hired aide + 1 operator
for 4 cages) PhP 4,000/month each, 13
months
4,0001326,00052,00013,00052,000104,000
Maintenance and repairs (3% of investment
costs per year if 1 cage, 2% if 4 cages)
2,2204,4401,437.755,75111,502
Total variable costs516,5311,033,062494,8431,979,3703,958,740
B. Fixed Cost
Depreciation costs24,20048,40023,66094,640189,280
Business license & other permits, 4 cages,
PhP 5000/year
1,5003,0003751,5003,000
Interest on loans to variable cost, 12% per
annum, 4.5 months loan per term
11,62223,24411,13444,53689,072
Opportunity cost of own capital, 0.5- 2.5%
interest/annum
3707401,7977,18914,378
Total fixed costs37,69275,38436,966147,865295,729
TOTAL COSTS554,2231,108,446531,8092,127,2354,254,469
Net income (PhP) = (gross revenue-total costs)10,07720,15432,491129,965259,930
ROI (%) = (net income/investment cost) x 10013.6%45.2%
Payback period (years) = investment cost/(annual
net income + annual depreciation)
2.161.28
Unit variable cost82.3878.92
Break-even price (PhP/kg) = annual total cost/
annual production
88.3984.82
Break-even production (kg) = total cost/selling
price
12,31647,271.88

Note: 2% discount on feed cost on bulk buying

References:
Reyes, O., Ayson, E. G., & Eullaran, B. (2016). Seed production of milkfish Chanos chanos Forsskal. Tigbauan, Iloilo, Philippines: Aquaculture Department, Southeast Asian Fisheries Development Center.

Reyes, O. S., de Jesus-Ayson, E. G. T., Eullaran, B. E., Corre Jr., V. L., & Ayson, F. G. (2015). Development and management of milkfish broodstock. Tigbauan, Iloilo, Philippines: Aquaculture Department, Southeast Asian Fisheries Development Center.

Gaitan, A. G., Toledo, J. D., Arnaiz, M. T., Ayson, E. G. D., Altamirano, J. P., Agbayani, R. F., … Marte, C. L. (2014). Milkfish Chanos chanos cage culture operations. Aquaculture Department, Southeast Asian Fisheries Development Center.

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3 Responses

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  2. ALI SHAFEEG says:

    Dear Sir/Madam,

    Like to get a feasibility and a business plan for milk fish as I intent to promote farming in Maldives.
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    Best regards.
    Ali Shafeeg

  3. Ivan Jessie John Duan says:

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