Correct stocking and breeding techniques for increasing production and income of green shrimp seedlings in soil ponds

Green shrimp

In order to save trouble, some shrimp farmers directly use the egg-holding shrimp left over from spring shrimp culture ponds to naturally propagate shrimp seedlings, and then directly carry out shrimp culture in the second half of the year in the original ponds without going through the clearing and drying ponds. In this way, year after year, the yield and benefit of circular culture will be very poor.

Why is the output and efficiency very poor? First, the character of green shrimp is degraded, the growth is slow, and the size of commercial shrimp cultivated is not large; second, the number of shrimp species propagated in the pond cannot be estimated, and there is a great disparity in the size of shrimp seedlings, and some prawns grow to 3~4cm maturity in August, and a number of autumn shrimp are reproduced, resulting in excessive density. The size of shrimp species in the pond is uneven, which directly affects the listing rate of green shrimp in the second half of the year and seriously affects the economic benefits of the pond.

In order to overcome the above shortcomings, mature wild shrimp holding eggs should be used to breed shrimp seedlings in earthen ponds during the breeding season. The main techniques are as follows:

1. Clear the pond and disinfect

Shrimp nursery ponds must be cleaned and renovated 20 days before breeding. However, the prawns were thoroughly cleaned and disinfected 15 days before hatching (before laying eggs). Shallow irrigation pond water 30cm, so that hidden in the mud Loach, rice field eel, snails and other automatic hole, and then use high-efficiency pond cleaning agent or pond cleaning medicine to kill the above pests. After 2 days, the medicine pond water was removed and the quicklime 400kg per mu was sprinkled in the whole pond. The ponds with high acidity should be applied more, and then soaked in 10~20cm for 3 days.

2. Fertilizer and water

After 3 days of quicklime disinfection, the pond enters the water to 30~40cm and sprinkles the whole pool with one bag of (2kg) high-efficiency algin or 250ml per mu. The new pond can also apply chicken manure 15~20kg, add water to the whole pond after fermentation, and after 3 days, the water is yellowish green or tea brown, that is, the whole pond is disinfected with 0.3g/m3 bromochlorohydantoin or 0.3g/m3 shrimp bacteria. After 2 days, the water is yellowish green or bean green. Gradually add water to the 70~80cm, and you can put the shrimp with eggs.

3. Set up incubator and concealment

Three green shrimp hatching cages were set up in each mu incubator, with a specification of 2m × 1m × 0.7m and a mesh of 90.10 mesh / cm2. They were fixed in the pond with bamboo poles, the lower side was 20cm from the bottom of the pond, the upper surface was 20cm, and the water peanut 0.5m2 in the box was arranged in strips, parallel to the long side of the cage for shrimp climbing. If there is no cage, you can also directly put some branches, water peanuts or nets in the pond and sink into the water about 30~40cm, which can be used as a habitat for green shrimp and young shrimp.

4. Selection of egg-holding shrimp

In mid-May, egg-holding prawns were purchased from fishing vessels. The individual egg-holding shrimp requires more than 5cm, strong physique, no disability, large number of eggs, bluish brown egg color, good maturity and uniform.

5. Time for stocking shrimp with eggs

It is generally controlled from the middle of May to the first ten days of June, 4~5kg egg-holding shrimp is reared per mu, and egg-holding shrimp is kept in each hatching cage. If there is no cage, egg-holding shrimp can also be directly put into the pond to hatch.

Green shrimp culture

6. Feeding and management

(1) feeding

Egg-holding shrimp are fed with bean cake or pellet feed. In order to make the shrimp hatch normally and reduce each other's residual food, the shrimp should be fed once a day, accounting for 3% or 5% of the shrimp's body weight.

(2) check the hatching of green shrimp.

After entering the pond, the prawns should inspect the pond every day to check their hatching and remove frog eggs from the pond. After the shrimp has been hatched (about 7-10 days), take the hatching cage together with the shrimp out of the pond.

(3) fertilization

About 3-5 days after entering the pond, the larvae of green shrimp can be detected to hatch. At this time, it is necessary to apply fertilizer in time, applying fermented chicken manure 25~50kg (equivalent to 5~10kg fresh chicken manure) per mu or sprinkling 250mg per mu. After 3 days, the water color can be cultivated to yellowish green or tea brown, transparent 25~30cm, at this time there are abundant natural opening bait of green shrimp in the pond, use a glass to get a cup of pond water, facing the sun, you can see many small white dot-like rotifers.

(4) timely addition of new water to promote the reproduction and growth of natural bait.

After baiting the pond, add water 5~10cm every 5 to 6 days according to the water quality, and keep the transparency of the pond water at 25~30cm, making the water fat and cool.

(5) feeding shrimp fry bait

Generally, the shrimp with eggs can hatch for about 7-10 days. After the seedlings come out, they can be sprinkled in the whole pool with 0.5~1kg soybean grinding milk per mu every day, twice a day. The early soybean milk needs to be filtered to remove the dregs, and one week later, it can be fed with unfiltered soybean milk. Ten days later, the soybean milk was gradually mixed with fish meal, bean cake powder, cooked wild fish and so on. After seeing the young shrimp, the crushed material can be fed directly on the shoal. After more than a month of cultivation, about 500000 shrimp seedlings can be produced per mu, and the specification can reach 1.5~2cm. At this time, it can be reared in a separate pond.

(6) Disease control

In the seedling stage of green shrimp, especially during the period of larval metamorphosis, the more common parasitic diseases are branch worm, condensed worm and so on. The prevention and control of the above diseases is mainly to keep the water quality tender and fresh, but can not make the water body aging.

(7) fishing of shrimp fry

After hatching, the shrimp larvae are carefully cultivated for about 30 days, and can be divided into ponds when the larvae reach 1.5~2cm. Shrimp seedlings can be pulled out with fish flower net, and adult shrimp culture can be carried out after counting. When fishing shrimp seedlings with a net, the action should be slow and strictly prevent the shrimp seedlings from suffocating to death. Green shrimp seedlings are not easy to use the net to pull clean, after pulling the net several times, then carry on the pumping fishing, when pumping water should pay attention to use the tight net to prevent the shrimp seedlings from being pumped away with the water. The caught shrimp seedlings are placed in cages with micro-running water to increase oxygen, and the shrimp seedlings can not be counted, transported and divided into ponds until the activities of the shrimp seedlings are normal, otherwise it will cause the shrimp seedlings to die.