Cage culture is a high yielding culture. The most economically advantageous. And the use of standard water. It also helps those who do not have land can turn to fish. If fish are released at an optimum rate, the fish will have better growth rates, thus reducing the shortening time. It is also convenient to handle the movement. Harvesting and investment are lower than other forms of farming. However, the tilapia culture in the cage may have some disadvantages, such as the problem of waterborne disease that can not be controlled. It can also cause environmental problems if no consideration is given to the amount and location of cages. And the river’s suitability. Therefore, the rearing depends on the finished food alone, which is wasteful in investing. The fundamental principles to be considered for cage culture are:
The area to be used for fish culture in cages should have good environmental quality. Because the fish in the cage is an intensive development focused on the management of food. Water quality is essential for fish farming. Typically, the water source used for raising fish in the cage should be a complete water source, i.e., it must have a low nutrient content. Or just said that the water must be clean and of good quality. The fish in the cage can be made in a large pond that cannot be taken altogether. In the reservoir, rivers, canals, marshes, as well as coastal areas, etc., the primary consideration is the appropriate location.
Transit of water Usually the fish in the cage will rely on the transfer of water through the enclosure to blow the bile and remove the waste out of the pen. The pool is changed to keep water quality at all times, so the area where the fish in the cage should have the current and wind. To help the circulation of water. The enclosure is right, but not severe. Especially for fish in cages in reservoirs or large ponds. Wind will be a significant factor contributing to the circulation of creek streams. The pen should be open space. Away from the umbrella and should not have water plants. Because trees and water plants often cover the wind and tides. This will affect the circulation of water in the cage.
depth of water The water should have a moderate intensity. When the cage is raised, the level of the cage should be high from the bottom of the pond, or the water surface is not less than 50 centimeters to allow water to flow well.
Far from disturbing Floating area should be away from the community. To prevent disturbances from the NHS, This will cause anxious stress. Injury to cage collision caused fish not eat. All this will hinder the healthy growth of fish fed or infectious diseases from the wound.
Type of fish to be raised and release rate
As mentioned above, cage culture is very suitable for tilapia culture. Since tilapia is a very easy-going fish, there is a strong market for it, especially for tilapia. This is a male fish. Will produce more than the female. The fish are large, and each fish size is not very different. The fish will be the same version, which is different from breeding tilapia sex with spawning. There is much fish. And there are a lot of ponds. Spoiled food And the area is not enough. The rate of discharge depends on several factors, such as the size of the release. Duration And the market size.
Cage culture is an intensive or semi-intensive fish culture that focuses on feeding to accelerate production and growth. It is recommended to use high protein foods that are appropriate for the size of the fish. Essential factors should be taken into account when feeding fish in cages.
Protein levels in foods. The optimum protein content for the growth of different age groups was different. For Juvenile and Fingerling fish, they require 30 to 40% protein, but in large fish, they need about 25-30% protein.
Feeding Time Tilapia will eat well. When the amount of dissolved oxygen in the water is high, it is the daytime. So most of them should be fed during that time.
The frequency of feeding Tilapia is a fish with no real stomach so that it can eat a little and digestion is relatively slow. Feeding a lot, Therefore, to be able to take advantage of the supplements, it is recommended that the food is given at least a few times. The optimal frequency is 4-5 times per day, which accelerates the growth. Grow and make the most economical return.
Feeding rate The amount of fish fed to the fish depends on the size of the fish and the temperature. The higher the water temperature, the higher the feed rate of the fish. Appropriate water temperature of 25 - 30 ? C should feed 20% of fish weight. For small fish in the fish, the feeding rate will decrease to about 6 - 8%. And for big fish. Feeding rate is only about 3 - 4%
Management between the parties. Cages should be checked to repair broken parts every week, as well as randomly tested fish to adjust the amount of food that is provided.
Harvesting is another consideration for harvest management. Cage culture should take into account the size of the fish and the amount of market demand.
Building cages Shape and size of the cage
Cages used for tilapia are shaped like squares. The shape of the enclosure will affect the flow of the tides into the cage. Compare the same quantity. Square cages have a surface area that provides more current than other compounds.
- The size of the rearing cages will vary. It depends on the needs of the farmers. Hanging Space And factors. Abovementioned Commonly used cages are rectangular cage size 1.2 x 1.2 x 2.5 or 2 x 2 x 2.5 m. Rectangle cage 4 x 2 x 2.5 m for cage construction cost. The cost per volume decreases as the size of the cage grows, but the yield per volume decreases. Due to the large cage, the current cannot be circulated thoroughly. The depth of the cage is 2.5 meters. When floating, the cage will be submerged in the water only 2.2 meters, with the outflow of water about 20 - 25 cm depth of the cage affects the growth. Fish, as well as Normal levels of dissolved oxygen in the water, are high at the surface. The amount of dissolved oxygen in the water is only 50-70% of the oxygen content at the surface, so the cage should not be too deep. As the fish fleets into deep, low oxygen content. This will result in low fish growth rate. The size of the cage depends on the factors of the culture, which the farmer decides by considering the amount of fish released. Small cage densely populated. High yield Easy management, However, the total yield may be lower than the larger cage mentioned above.
Also, the cage wall above. Use green nets width of about 90 cm stretched to prevent food out of the cage during feeding.
- Cage Competition Should hang the cage at a distance of not less than 3 meters to prevent the corners
between the pens to reduce the oxygen deficit. If necessary, use a hose or water pump to help the circulation of water in the cage and increase the amount of oxygen in the water as well. Must be appropriate to the size of the fish to prevent fish from escaping. It also has to provide a good flow of water and avoid the small fish outside and disturb the fish in the cage. The mesh size should not be less than 1.5 x 1.5 cm so as not to obstruct water circulation through the cage. The cage should have a lid which may be made of the same kind of nets as the cage or the appropriate material. This is to prevent the fish from escaping and the fish from jumping outside. Including avoiding birds from eating fish.