Raising milkfish (Chanos chanos) in marine water became popular when finfish feed became available in the local market.
Also, the Philippines being an archipelago, it has miles and miles of coastline that gives big opportunity in raising bangus in the marine waters. Since raising bangus in bodies of water inland has limits, opportunities in the marine waters are now being explored.
To be able to have a successful bangus business, you have to have good facilities to grow the fishes in.
Your pond should be in good condition that holds clean water, and your people must know how to manage ponds and bangus farms. You can also take part in a cooperative which can be of financial support.
The bangus is also known as milkfish. It is a delicacy and is appreciated very well as sinigang, dried, or grilled.
A new way to raise bangus
There was a study conducted by the Bureau of Fisheries and Aquatic Resources, to determine whether it would give better results if marine nets are used in raising bangus in marine water. The results are good. The production increased almost ten times using the nets, rather than fishponds.
These good results are due to the tidal currents. This will allow putting as many bangus fish in an area without crowding them, thus creating bad effects in their growth.
However, it required money for feeds. You have to be totally dependent on artificial feeds.
Since milkfish fry nursery is difficult to manage in marine net cages, only fishes that are 30-45 days old are places in the net cage. Transport fingerlings from the nursery to the cage using oxygenated bag. The number of fishes per bag should be from 40 to 100, depending on the distance to be traveled.
Once you arrive at the cage site, adjust your fish to the sea water temperature. During this time, the fishes can be sorted, sampled, and counted . After which youll place them in the formation hapa for the first 45 days of culture, following the feeding scheme.
Milkfish weighing 30-45 grams are transferred to the grow-out cage where they are fed grower or juvenile pellet during the first month. Feed them finisher or adult pellet from the second month onwards.
For you to be able to monitor the growth of your fishes, sample at least 50 fishes every 15-days.
Clean your cages once a week and check for broken nets. They are harvested after 4 months of culture.
By brackish water ponds
The milkfish can live on natural food like lab-lab, lumot, and plankton grown by fishfarmers using some techniques. You can grow lab-lab by drain the pond completely and dry it for 1-2 weeks until the soil cracks.
1. Don't expose it ot the sun too long, because it will make the soil hard and powdery. Destroy unwanted organism by spreading tobacco dust over the moist bottom, or by using ammonium sulfate fertilizer and lime.
2.Apply chicken manure at 2 tons/hectare. Floor to a depth barely covering the whole bottom and spread urea (45-0-0) at 15 kg/ha 2-3 days later. This will make the chicken manure breakdown faster.
3. Increase water slowly over a period of 1 months, at 3-5 cm each time until it reaches 30-40 cm deep. A sudden increase in water level will make the lab-lab float.
4. To increase lab-lab growth, apply inorganic fertilizer (16-20-0 or 18-46-0) at 50 kg/ha every 12-15 days. Get rid of snails by using molluscicide applied at 300-400 kg/ha, or collect snails and burn them. These snails destroys the lablab.
Transfer fingerlings to the pond as soon as it is ready for stocking. You can buy fingerlings from suppliers, or you may want to have a stunting pond nearby for enough supply of fingerlings all-year round. These fingerlings are normally held in hapa nets few before putting them in the pond, or stocking. If your stunting pond is nearby, you can transfer the fishes to the stocking pond through a canal, where there is flowing water, directly to the stocking pond.
For long distances, put the fingerlings in oxygenated bags. Stocking should be done at the cooler time of the day.
There can be around 5,000 fingerlings/hectare.
- When the lab-lab start to decrease in number, add water to the pond to a level of 80-100 cm. Apply inorganic fertilizer (16-20-0) at 50 kg/ha every 1-2 weeks.
- Coincide fertilizing during spring tide cycles. Replace about 1/3 of the amount of water every application of fertilizer. In hot months, you will need to put water more often in your pond because evaporation takes much of the pond water.
- In rainy months, drain water from the top to preserve the saltiness of the water.
- In the middle of the culture period, the lab-lab may be totally used up. At this point you can turn to artificial feeding. Give artificial feed at about 5% of the average body weight per day using commercial feed.
- If your milkfish is stressed, they would swim in circles at the surface, and they appear to be gasping for breath. This stress can be caused by not enough dissolved oxygen.
- Refill water at first opportunity. Splash it in a piece of wood to add oxygen. Be on the look out for bad weather conditions. Storms in the middle of hot months will cause changes in the temperature of the pond which may cause fish kills.
Harvest and post-harvest
- To gain the highest profit, culture period must be 60 days. The harvest is up to 2-2.5tons/ha.
- The most common and undisputed technique in harvesting is the pasulang method, wherein the fish are made to swim against the current. Gather the fishes in a catching pond and use drag nets to collect them.
- Scoop, wash, and stun the fishes in chilling tanks of boxes. If there are fishes left at the bottom, pick them by hand, and after stunning them by chilling, pack them in wooden or metal tubs (baeras) or baskets, or Styrofoam boxes filled with ice and transport them to the market of to dealers.
- Bangus can be sold fresh, dried, smoked, deboned, pickled, or they can be sent to canneries for processing.
- Choose a good site to raise the bangus. Choose a place that it not polluted. It should also be free from floods, and is protected from strong winds and typhoons. The water should not fall below 1m in during low tide. An ideal temperature is 26-30C.
- It will be extra help if the place is easy to access. This will be helpful once you start marketing your bangus.
Cage design requirements
Net cages are the most economical to use. Sizes that are easy to manage are as follows:
10m x 10m x 2.5m = 100 sqm
15m x 15m x 2.5m = 225 sqm
20m x 20m x 2.5m = 400 sqm
25m x 20m x 2.5m = 500 sqm
The cages you have to use are the formation hapa, and the grow-out cage.
The net cage may be pegged to the mud bottom by wooden bamboo posts, or they can be floated at the water surface by bamboo raft or by plastic buoys. It should also be covered with nets to prevent the fishes from jumping of the cage.
Sources:Milkfish Cage Culture in Marine WaterBFAR National Brackishwater Aquaculture Technology Research Center; Semi-intensive Milkfish Culture in Brackish water ponds: SEAFDEC/AQD; Paggawa ng Tinapang Isda leaflet by BFAR-NIFTDC; www.da.gov.ph; photo from www.abtinnovia.com