Mlilkfish (Chanos chanos) or “bangus” as they are called locally comprise the bulk of aquaculture fish production in the Philippines. They are hardy and fast growing, and can be raised in fresh and brackish water ponds and pens. Being one of the cheapest sources of protein, milkfish are acceptable to all socioeconomic strata In the country.
Biological Characteristics
Milkfish are:
- Filter feeders. They have no teeth but have fine gill rakers that concentrate microplankton.
- Benthic feeders. They nibble or browse on adhering or even floating lab-lab, periphyton, or lumut
- Daytime feeders. They feed less at night.
- Euryhaline. They can withstand extreme but gradual salinity fluctuation (from 0 to 100 ppt) but grow faster in natural waters of 0-40 ppt.
- Phytophagus. They eat plant materials, and can easily digest plants owing to their long intestines. But milkfish can also adjust to artificial feeds- rice bran, trashfish, fish pellets- an hence are also considered omnivorous.
- Resistant to diseases and are not cannibalistic. They do not prey on each other and are not easily affected by infectious disease, hence, they can be grown in relatively higher densities.
- Exhibit compensatory growth. Milkfish growth may be stunted under adverse conditions, but they can grow fast when conditions become favorable again.
Design and operation of Modular Pond System
Culture of milkfish from fingerling to marketable size is carried on in three stages using ponds with progressively increasing area. The proportion of rearing ponds is 1:2:4.
To design the modular pond system, the topographic map is consulted first followed by the actual evaluation of the intended farm site. Different positions of the modules are normally prepared and evaluated, and most efficient set-up is selected. The major pond components are properly identified, using moneclatures such as NP for nursery pond, TP for transition pond, FP for formation pond, and RP for rearing pond.
From initial stocking, the fish are reared for at least 30 days in each module. The fish are moved periodically from one module to the other by inducing them to swim against the current (pasulang). Subsequently, vacated compartments are again prepared for about 15 days for the incoming stock. With this system, extra cropping is obtained without necessarily over-taxing the natural food supply. One important requirement of the modular system therefore is sufficient buffer stock of milkfish fingerlings (at least 25 grams each) in the .stunting ponds. If the fish farmer uses bigger fingerlings for stocking, he can produce marketable fish in three months of culture, and have 6-8 cropping in one year.
Pond Preparation
The amount of lab-lab grown in the pond is dependent on the manner of pond preparation. Lab-lab is grown chiefly of organic and inorganic fertilizers.
Preparation of pond for lab-lab starts one or two months before stocking the fingerlings.
In order to obtain the best growth’,” eradication of unwanted species and maintenance of good water quality is necessary.
Basic steps:
- Drain the pond completely and allow to dry for about 1 to 2 weeks until the soil cracks: Prolonged drying is not advisable as it makes the soil hard and powdery.
- Eradicate unwanted species by using organic pesticides such as tobacco dust, derris root, and/or a combination of fertilizer and lime. When using tobacco dust, spread over moist bottom 300 to 400 kilograms per hectare and allow to stand for about a week. The application of a combination of hydrated lime and ammonium phosphate (21-0-0) is done by broadcasting lime, ammonium mixture at a ratio of 5:1 on wet areas of the pond bottom during a ‘ sunny day. Reaction of lime and fertilizer releases heat and ammonia which effectively kill unwanted species in the pond.
- Apply chicken manure at 2 tons per hectare. Flood to a depth barely covering the pond bottom, then apply 15 kg per ha of urea or 45-0-0 two to three days later to seed up the decomposition of chicken manure. Method of application is by broadcasting.
- Increase depth gradually over a period of one to one and a half months, adding 3 to 5 centimeters to the water level each time until the stocking depth of 30 to 40 cm reached. An abrupt increase in,depth causes , lab-lab to detach and float. Install fine mesh screens to the gates to prevent re-entry of wild species.
- Subsequent application of 16-20-0 at 50 kg per ha.or 18-46-0 at 20 kg per ha may be made at 1 to 2 weeks interval to bolster the growth of lab-lab.
Stocking in Nursery or Transition Ponds
Newly arrived are normally contained in double-lined oxygenated Bags with salinity ranging from 15 to 25 ppt. The fry are usually emptied into plastic basin to sort out predators. The fry are stocked in the pond in the early morning or late afternoon when the temperature is cool to prevent temperature shock.
If salinity of the water in the transport bag and that of nursery pond are approximately the same, the fry may e stocked directly into the nursery pond.
Stocking rate is from 30 to 50 fry per sq.m. However, if the salinity difference is over 5 ppt, acclimation should be done to prevent salinity shock during transfer. To acclimate, gradually add pond water inside transport bags until the salinity is equalized.
The fry grows to fingerling size (3-5 g) after 30-45 days of culture with average survival of 60 to 70% newly-grown fingerlings may be stocked right away in the rearing pond, the rest of the fingerlings may be held temporarily for 6 months to one year in transition, or stunting ponds at the density of 10-15 fingerlings per sq. m. in the transition pond, the fingerlings subsist on natural food like lab-lab, lumut, or plankton with or without supplemental feeds.
Stocking in the Rearing Ponds
As soon as the remaining ponds are ready for stocking, fingerlings are caught from the nursery or stunting ponds and are held in a fingerling seine. This seine may be set in a canal where it is carried slowly closely to the pond where the fish are to be stocked. If it is not possible, place a few hundreds of fingerlings at a time in plastic bags and carry to the pond. For longer distances, oxygenated plastic bags will be necessary to ensure good survival of fingerlings.
It is best to count the fingerlings to prevent under or over stocking. The fingerling seine should be positioned near the mouth of the gate where flowing water can sustain the fish that are crowded in the seine. Stocking of fingerlings should be done during the cooler part of the day.
Care of Stock
The main concern after stocking is the maintenance of optimum water condition for both the fish and the natural food.
When using lab-lab as the food base, it is’ necessary to apply fertilizer (16-20-0) at the rate of 1 bag (50 kg) per ha every 12 to 15 days to maintain good growth of natural food.
Abnormal occurrences such as the fish appearing to be grasping at the surface or swimming in circles may at times be experienced. These are believed to be indications of stress associated especially with insufficient dissolved oxygen. Water should be replenished at the first opportunity. If replenishing water is not possible, water from the adjoining pond may be made to flow so the water is agitated. Pumps may also be used in such an emergency.
Harvest and Post-Harvest
So far, the most common and the best technique of harvesting milkfish is still the “pasulang” method or inducing the fish to swim against the water current. The fish are gathered in the catching pond or canal system during spring tide, and drag seines are used to collect them.
They are scooped into chilling tanks or boxes where the temperature is low enough to kill them. In the chilling tanks or box, a 1:1 ratio of ice to a kilogram of fish is enough to lower the temperature of the fish to about 4 degrees Celsius in two (2) hours. The remaining fish on the now totally drained pond are collected by hand.
Milkfish are sorted according to quality (size, freshness, among others) and then packed into wooden boxes (kahon), metal tubs (banera), or bamboo baskets (kaing) ready for retailers and fish brokers. Harvested bangus may be sold fresh, dried, smoked, deboned, pickled, or sent to cannery for processing or packed on cans like sardines.
Related article here.
For more information, contact:
Bureau of Fisheries and Aquatic Resources
Gitnang Luzon Fisheries Extension
Training and Communication Division
2/F Berzonn Bldg., San-Agustin, City of San Fernando, Pampanga
Tel. Nos. (045) 963-5515
PCAMRD Liaison Office
2nd Floor, Rm. 205 PTRI Bldg. Gen. Santos Ave.,
Bicutan, Taguig, Metro Manila
Tel. Nos: (02)837-2071 up to 82 local 2430
2010 · All Rights Reversed ·
dear sir/mam
my concern is the exact stocking density for rearing pond consedering that im using bansotan or trnasetion pond before stocking it to rearing pond at a size of 3 fingers and a depth of 40 cm water level and a target harvest of 60 days and my target size is 4 pcs in one kl. pls be realestic and my pond area is 1.6ha so 16000 sqm water area
thank u
Good evening everyone,
October 12 2009
I have some problem of my fish farm maybe be you cant help or you can give some tips how to improved it. I stay in Bohol province which is my home town is.
i been harvested twice but i never been make a profit at all always lost money.
So , i decided to get a new information in website that it can help me to improved my business.i have 3.5 Hectares which is divided into 5 square with
one for keeping the fingerling (baby bagus)
This is some of inquiry to you
i hope you can help me
1)Main problem is water ‘m quite faraway from sea side area so i only depending the high tide or high level of the water and very rear i cant change
the water.
2) Is it possible i cant use a wheel water instead of waiting for the sea water to come but wheel water is not very salty all how is it possible to do that.
3)Or is i cant use a salt to mixed with wheel water
4)Cant be Lab Lab grow in a mixed fresh water / chicken shit can be done with mixed water.
5)Because now I’ve been using feeds means Fertilizer and i feel scared at the moment because i feel to expensive for me to do it again I’m lost.
6) Is there anyway i can do better than what i was doing now about my Fish Farm .
I hope you give me a better information about my situation right now
waiting your reply and thank you in advance anyway.
Your sincerely
Genny Rosales
Genny. email me at norman.whit@yahoo.com
I can help you.
Good morning to all:
I’m a starting milkfish farmer here in the philippines,Iloilo city. I was hoping that you could give me some advice and answer a couple of my questions.
So id like to give you an overview of the land:
my pond consists of a 1ha rearing pond, .5ha nursery pond and another 2.5ha(undivided). This pond has been operational for more than 20 years until a few years(3-4yrs) back in which operation has been stopped. But recently this has been passed on to me and this year(august) i was able to harvest 200kg of milkfish in the 1ha from a stocking density of 2000pcs/ha, which is very low considering from all the reports and researches i have read. My sole feeding method was growing Lumot(the filamentous type). I was not able to use lab-lab or artificial feeding methods due to financial constraints. Currently i have finished pond preparation in the 1ha and growing Lumot as the sole food supply. I am considering stocking 5000pcs milkfish about 30-40g/pc. And estimate a harvest period after 3 months with the last month considering giving artificial feeds in the same hectare.
Here are just a couple of my questions:
1. Considering what i have in mind, in your experience, is it possible to harvest at least 1ton/ha with my method?
2. Is there a cheaper and, not necessarily the best, alternative to artificial feeds other than lablab?
3. Would it be cost effective if i placed 1 paddle wheel in 1ha at the current stocking rate or is there no need?
4. Is it possible to grow lablab and lumot at the same time?
These are just a few questions i have in mind, and i am just starting to learn the ropes and i hope to bring my fishery to a very efficient state of production of milkfish, and even later on considering bringing in more modern methods of production. Any advice, comment or opinion from anyone would be very much welcome and id be very very thankful
Julian Corteza
Mr. Corteza:
You are veerry near SEAFDEC (Southeast Asian Fisheries Development Center) in Tigbauan. I suggest that you get assistance from them. Im sure that they will be more than willing to assist you.
Reur inquiry:
1. If you stocked 5,000 fingerlings and at a recovery rate of 80%, you should be able to harvest 4,000 pcs. If you harvest at about 1/2 kg each, you should harvest at least 2 tons. It will be more if you grow your fish to a bigger size.
2. Lablab should be enough food for your stocking rate of 5,000/ha. If you find your lablab insufficient, I suggest that you convert your nursery pond (0.5ha) into a kitchen pond, i.e. fertilize it with chicken manure and inorganic fertilizer. Once lablab blooms, you can transfer them to the pond with bangos.
3. You can make your own farm made feeds which is a lot cheaper that commercial pellets. I wrote an article on this at the Agriculture Magazine which will come out in Jan 2010.
4. Lumot and Lablab are the same. If you mean the lab-lab that float at the surface of the water, You will achieve this with chicken manure.
5. At your stocking density of 5,000/ha, an aerator will not be necessary.
I hope that I havee been of help.