CATDOLL : CATDOLL: What are the benefits of co-culture of whiteleg shrimp and tilapia?

What are the benefits of co-culture of white shrimp and tilapia?

The mixed culture model of tilapia and white shrimp can effectively overcome the shortcomings of tilapia price fluctuations and shrimp diseases and high risks. After promoting the tilapia-white shrimp compound culture model by using the principle of fish and shrimp mixed culture technology, the average tilapia yield per mu in Zhuhai Pingsha Tilapia Breeding Base was 1,630 kg, a year-on-year increase of 28%, and the total output value of fish and shrimp was 66 million yuan (of which the output value of tilapia was about 53 million yuan and the output value of white shrimp was about 13 million yuan), a year-on-year increase of 31%, the total profit of fish and shrimp was about 18 million yuan, and the average profit per mu was 3,300 yuan. The net income of each household generally reached 20,000 to 50,000 yuan.

Technical points:

(1) Free-range model

The mixed culture mode of tilapia and Penaeus vannamei (where Penaeus vannamei adopts the mode of one-time stocking, two-time stocking and three-time stocking), the specific stocking density and method are shown in Table 1. The stocking time of tilapia is the end of March and the beginning of April.

Table 1 New ecological model of polyculture of tilapia and Penaeus vannamei

Tilapia stocking density (tails/mu) Tilapia stocking size (body length) (cm) Prawn stocking density (10,000 tails/mu) Prawn stocking interval (days) Prawn size (cm) Tilapia yield per mu (kg) Prawn yield per mu (kg) Net profit (yuan/mu) 21.7-2.2 Stocking in three times: first stocking 1.5 second stocking 1.0 third stocking 1.0 20 days earlier than tilapia stocking interval 70-80 days stocking interval 60-65 days stocking 1.5-2.0 1.7-2.2 Stocking in two times: first stocking 2.0 second stocking 1.5 20 days earlier than tilapia stocking interval 70-80 days stocking 1.5-2.0 1.7-2.2 Stocking once: stocking amount 3.5 20 days earlier than tilapia 1.5-2.0 966 (2) Main management measures

① Preparation before stocking: After harvesting fish and shrimp at the end of the year, the pond is dried. Before stocking, the pond is disinfected. There are two methods: dry pond cleaning and pond cleaning with water: one is dry pond cleaning. After repairing the fish pond, only 8-12 cm of water is left at the bottom of the pond. 4-5 kg/mu of tea bran or 50-80 kg/mu of quicklime are sprinkled on the whole pond. After 3 days of sun exposure, the water is returned and the injected water is filtered through a 40-60 mesh net to remove impurities; the second is pond cleaning with water. The whole pond is sprinkled with bleaching powder (about 30% effective chlorine) at a dosage of 20 g/m3; or 80-100 kg/mu of quicklime is sprinkled on the whole pond for every meter of water depth. Before stocking seedlings, "test the water" to confirm that the toxicity has disappeared before stocking.

② Feeding: mainly compound feed, supplemented with cake meal and bran. The daily feeding amount is 3% to 5% of the total weight of the fish in the early stage, and 2% to 3% of the total weight of the fish in the later stage. Feed once in the morning and afternoon. Pay attention to the feeding situation, increase or decrease the feeding amount appropriately according to weather changes, stop feeding on rainy days or when the fish float to the surface, and do not need to feed the white shrimp specially.

③Daily management: Patrol the pond every morning and evening to observe the fish's feeding and water quality changes. Add water once every 15 to 20 days. In hot seasons, the frequency of water injection can be increased depending on the situation. Keep the water transparency of the pond at about 30 cm. When the water color is dark, sprinkle quicklime to adjust the water quality. The amount is 15 to 20 kg/mu. Equip one aerator for every 2 to 3 mu of water surface. Turn it on once in the afternoon and early morning every day for 2 to 3 hours each time. In hot seasons, it should be turned on 24 hours a day. (3) Catch the fish

The time of fish removal from the pond is determined according to the fish removal specifications. When the water temperature drops to 15°C, all tilapia should be caught. The shrimp are caught in cages and when they reach the market specifications, they are caught and put on the market irregularly according to market demand. (4) Economic Benefit Analysis

The tilapia-vannamei composite farming model can reduce farming risks and improve the farming efficiency of ponds. Taking farming efficiency as the evaluation index, the vannamei fry were released every 60 to 80 days, and a total of three batches were released. This can effectively improve the economic benefits of the tilapia-vannamei mixed farming model, which is 50% higher than that of tilapia alone.

Suitable areas: Coastal areas suitable for tilapia farming require a certain salinity (5-10).

Note: When stocking tilapia fry, the water temperature should be kept above 20℃; whiteleg shrimp should be stocked 20 days earlier than tilapia.

Penaeus vannamei is a miscellaneous, partial-forage or carnivorous animal. Its demand for protein in feed is lower than that of other marine shrimps, about 23% to 41%. It feeds both during the day and at night, and feeds less but more often. The advantage of mixed culture is that it can enhance the self-purification ability of the aquaculture water body and block the spread of shrimp diseases. Tilapia feed feeding: Tilapia has a miscellaneous diet, but it grows faster when fed with compound feed. Domestication and feeding began on the third day after stocking, and generally began to feed in groups after one week. Choose tilapia pellet feed of different specifications for feeding according to the growth of tilapia, and the feeding amount can be flexibly adjusted according to the weather, water quality, and fish appetite. The daily feeding amount is 3% to 5% of the fish body weight, and it is fed at a fixed point twice a day. When feeding, try to spread it as evenly as possible to give the fish the opportunity to feed as much as possible. Send a feeding signal before each feeding, and gradually form a habit. Accurate feeding is the key to improving economic benefits.

How can we keep freshwater whiteleg shrimp from dying and improve their survival rate when shipping them long distances?

First, a special shrimp transport vehicle is needed, which has the following features: live shrimp transport barrels (usually rectangular, with a volume of 0.8 to 1 cubic meter) are insulated and have a backup generator. Before shipping, the vehicle condition must be checked, fuel must be replenished, and the oxygenation equipment must be debugged.

Second, stop feeding the shrimp for one day before shipping. First, it is easier to catch (using shrimp cage fishing method); second, the shrimp is transported with an empty stomach, so there is no feces discharge, which is conducive to clean water quality during transportation and reduces the activity of the shrimp. At the same time, it should be noted that sick shrimp and molting shrimp should not be shipped, as they are weak and easy to die;

Third, calculate the weight of shrimp in each shrimp basket according to the distance of transportation;

Fourth, the water temperature of shrimp transportation should be controlled between 14 and 16 degrees Celsius throughout the whole process, so that shrimp can be transported in semi-dormant state, and shrimp can be prevented from being active due to high water temperature, which will increase the oxygen consumption of shrimp and cause them to be injured. At the same time, spare ice cubes should be added to the shrimp transport vehicle, and the water temperature and water level should be checked every two hours during transportation. If the water temperature is high, add ice, and if the water level is low, add water at the nearest water adding place.

Fifth, the adaptability of whiteleg shrimp to new environments is poor, especially for freshwater whiteleg shrimp. Therefore, it is not advisable to use all new water for transportation. For seawater whiteleg shrimp, half of it should be pond water and half should be new water. For freshwater whiteleg shrimp, it is best to use all original pond water.

Sixth, the salinity of the transport water: according to the salinity of the shrimp pond, it is better to add 1 to 2 kg of sea crystal to the transport water. This is treated according to the specific situation. At the same time, after adding sea crystal, the aerator should be turned on in advance two hours before loading the shrimp to allow the salt to fully dissolve in the transport water.

Seventh, regulation of transport water: before loading the shrimp, "high-activity factor" or "seawater factor" and drugs to prevent stress response should be added to the transport water.

If the above points are achieved, the survival rate of shrimp will be at least above 90%.