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?

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.

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

 

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

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 (as of 2016)

	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 (as of 2014)

	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

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

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

Milkfish Fry Sufficiency

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	AEM 45 Fingerlings production of hatchery-reared milkfish (Chanos chanos) in earthen nursery ponds (2010) 32 pp EB Coniza et al.  An extension manual detailing the three types of nurseries, site selection, and pond preparation; fry selection, handling, transport, acclimation and stocking, fish monitoring, feeding, and harvest; and economics. Each copy costs US$6
	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. Each copy costs US$7
	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 Each copy costs US$8
	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. Each copy costs US$4

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