Intensive cage and net pen farming

Cage farming is a traditional production form and the single most preferred production method for tilapia in Vietnam. Cage and net pen farming occurs along the entire Mekong River and is concentrated in the provinces close to the Cambodian border, An Giang and Dong Thap. As of 2015, there were an estimated 490,000 m3 of cages dedicated to tilapia farming throughout Vietnam. Since tilapia has a high tolerance for low water quality, many commercial and export oriented companies are switching to pond farming.

Key features
Average stocking density

100 to 120 pcs/m3

Average productivity

120 kg/m3/crop

# of crops per year

2

# of days per crop

150-200

Harvesting season

All year round

Type of farmer

Small-scale and corporate

Potential risks
  • Poor control of sudden disease outbreaks
  • Lack of control of water quality

Type of farmers

Many households engage in small-scale fish farming. Cage farming has many advantages for farmers, such as low investment costs, high productivity, easy harvest and predator control. Small farms normally sell to the domestic market. Some companies engaged in the pangasius industry also engage in tilapia cage farming and sell all raw materials to processors and exporters who sell tilapia fillets and use the waste as input for fish meal and oil production.

Production and harvesting system

Commercially oriented cage farming of tilapia is practiced in monoculture. Net cages with a wooden frame that float on the water surface with cages reaching depths up to 5 meter are mostly used by both households and corporate farms. Some use submerged cages. In smaller rivers farmers also use pen culture, where entire areas are fenced in order to raise tilapia in pens that stretch over a total surface of up to one hectare in size. An obvious limitation is the importance of water transport in Vietnam and the fact that cage farming is only possible in places where it does not restrict shipping.

Harvesting happens periodically throughout the year where the entire cage or net pen is harvested at once. Fish grow to harvest weight in five to seven months, allowing for two crops per year. Most farmers harvest at a size of 500 to 700 grams depending on demand.

Stocking densities and productivity

Stocking happens periodically throughout the year. Fingerling sizes vary depending on the preference of the farm operator and range between 10 and 50 grams. Cages are typically stocked with 100 to 120 pcs/m3, but can reach up to 180 pcs/m3. Compared to pond farming, tilapia culture in cages is much more productive and stocking densities can be tenfold or even higher. Average yields are around 120 kg/m3/crop.

Use of seed, feed and other inputs

Fingerlings come exclusively from approved hatcheries. Most corporate tilapia producers are vertically integrated and have their own hatcheries and nurseries. Nursery ponds are used to grow fingerlings to a size that increases the survival rate to over 95%.

All corporate producers use pelleted feed from approved feed mills. Chemicals are generally not used. Most corporate farms in Vietnam are eco-certified and need to abide to very strict rules as regards chemical and antibiotics use.

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