POLYCULTURE OF TILAPIA IN SHRIMP PONDS

Polyculture of tilapia in shrimp ponds increases the competition between the two species; take advantage of leftovers and organic waste in ponds; limit water pollution, prevent the spread of diseases in shrimp; bring high productivity.

 Prepare the pond

 For high-density white shrimp (TTCT) ponds (100-200 shrimp / m2), tilapia can also be dropped by netting in the middle of the pond where shrimp waste is gathered.

 Ponds with an area of 4,000 - 6,000 m2, density of 40 - 50 shrimp / m2 (TTCT) and 7-15 shrimp / m2 (giant tiger shrimp) can directly drop tilapia into ponds.

 Ponds are drained, remove trash, apply lime, take water, cause color like normal shrimp ponds. Intensive aquaculture ponds, when preparing the pond, it is necessary to design a net in the low-lying area in the middle of the pond, accounting for 7-10% of the pond area, thin meshes (size 0.5 - 1 cm) for waste to pass through the net as a final food eat for fish. The net is firmly tied, above the net is 40 - 50 cm higher than pond water.

 Stocking

 After installing the air blower, causing water color, proceed to stocking shrimp and rearing as procedure. After 20 days of rearing, a lot of waste has been accumulated and tilapia was released.

 To avoid fish breeding in shrimp ponds, tilapia should be selected. For high density TTCT ponds, short farming time, should drop tilapia net, large size (15-20 children / kg), the size of the fish must be larger than the mesh size.

The density of fish stocked in net raceways is 6-8 fish / m2.

 Low density shrimp ponds, should size 40-50 fish / kg, a density of 1 / 1-2 m2 pond.

 Management and care.

 In high density TTCT ponds, tilapias stocked in net racquets often do not feed so that the fish eat the waste of shrimps gathered by air fans to gather. Every 15 days / time to make a net to make waste easily pass through.

 Shrimp ponds with tilapia grafts need to be based on the feeding habits of shrimps and tilapia to feed shrimps properly. Shrimp often feed strongly at dusk and dawn; tilapia eat strong prey during the day.

 Therefore, in order for shrimp to be provided with enough food, it is recommended to feed at two main meals (accounting for 80% of the total amount of feed per day) at the time before morning and after dark (5 hours and 18 hours), ban Only a small amount of shrimp (20%) was used to avoid tilapia for shrimp.

 Food is stocked in a shallow area around the pond. Uneaten food and shrimp waste will be used as tilapia by the tilapia.

 During farming, tilapia using uneaten food and shrimp waste will limit the amount of N and P in the water, but during excretion, shrimp and fish will emit a small amount of NH3.

If this amount exceeds 0.1 mg / l, it will be toxic to shrimp (growth inhibition, reduced disease resistance, increased susceptibility to environmental conditions, such as lack of oxygen and fluctuations of temperature ...).

So can change the water periodically 1 month / time; change 15-20% of pond water each time.

If conditions for changing water are difficult, apply probiotics once every 10 - 15 days.

Maintaining aeration machine to increase dissolved oxygen content, prevent shrimp floating head, gathering waste to feed fish.

Regularly check the pond , observe the water color, monitor the activity and feeding of shrimp, timely prevent and treat, need to record daily diary as a basis for adjusting the food and treating Disease management.

 Harvest

 High density stocking ponds can be harvested after 2.5 - 3 months. For tilapia reared in a racetrack, the harvest will be as simple as collecting all the tilapia in a net, then pulling the shrimp net. If the tilapia has not reached the commercial size, it can be transferred to another pond.

 For shrimp ponds stocking tilapia directly, after 3-4 months of farming, they can be harvested. Based on the differences in the behavior of shrimp and tilapia, shrimp harvest after 8pm with bait in net cages.

 At this time, the tilapia is less active and prey, while the shrimp catch strong bait, so they will enter many cages. Each pond put 5-6 net cages, 2-3 m3 size to collect shrimp. Shrimp can be harvested continuously for a week, when the amount of shrimp in the cage is small, use a net to collect both fish and shrimp.

After each crop, 2-3 tons of giant tiger shrimp, 5-6 tons of shrimp and 1 to 1.2 tons of tilapia per hectare can be harvested. In the form of tilapia polyculture, it can reach 9 - 12 tons of TTCT and 0.5 - 0.8 tons of tilapia per ha.

Currently, this polyculture has been successfully applied in the Philippines, China, Thailand and in two provinces of Soc Trang and Bac Lieu in Vietnam.

 Benefit

When tilapia is released into shrimp ponds, it will significantly reduce harmful Vibrio group bacteria and viral diseases, reduce solid waste, stimulate green algae growth,

but not affect the growth of some types other useful algae.

 In addition, tilapia also helps kill some intermediate hosts carrying pathogens and when dead shrimp die in the pond, they are eaten immediately by tilapia, limiting the spread of disease.

 Shrimp farming combined with tilapia reduces the rate of premature mortality

 Tilapia helps control acute hepatopancreatic necrosis in shrimp

 Tilapia prevents the occurrence of shrimp pathogens

 Polyculture of tilapia with shrimp can improve water quality

 Polyculture with tilapia saves costs