Six key steps of shrimp culture
First of all, the condition and cleanliness of the pond. Freshwater ponds or shrimp ponds with an area of 3 ~ 5 mu, water depth 1.5 ~ 2.5 m, sufficient fresh water sources, no pollution and sandy bottom should be selected.
Second, fertilization and bait cultivation. 1 before the shrimp fry are stocked, they are filtered with a 60-80 mesh sieve, and the water is 30 cm, and 50 kg of fermented animal manure or 5 kg of urea are applied per mu to cultivate the basic bait.
Third, shrimp seedlings are stocked. Generally, shrimp seedlings can be raised in late May when the water temperature is stable at 18 ~ 20℃. Shrimp seedlings need to be diluted for more than a week, and the proportion is below 1.003 before they can be stocked. Generally, 30,000 to 40,000 shrimps with 0.7 ~ 1.0 cm are put per mu, and seedlings below 0.7 cm are temporarily raised. 80 ~ 10 ~ 20 cm silver carp can be mixed in shrimp ponds.
Fourth, bait feeding. In 1 month, shrimp larvae basically do not need to be fed with compound bait, and mainly rely on plankton in the pond for food. After 1 month, feed the compound bait, supplemented by fresh fish and shellfish, and the feeding rate is generally 3% ~ 5% of the shrimp weight. The feeding amount can be appropriately increased from July to September. The feeding frequency is 2-3 times a day, and the feeding amount accounts for 1/3 in the daytime and 2/3 in the evening.
Five, water diversion and disease prevention. After 10 days, shrimp seedlings began to be gradually added with water, with a weekly rate of 10 ~ 15 cm. Change water for 20 ~ 30cm every 2 ~ 3 days in high temperature season. Fill the pond with 5 ~ 10 kg of quicklime every half month or so, which not only improves the water quality and sediment, but also can sterilize and promote the growth of hulling. At the same time, 1 ‰ ~ 3 ‰ garlic bait should be mixed for 3 ~ 5 days in 1 ~ 20 days.
Sixth, arrest. Generally, after 80 ~ 100 days of culture, shrimp can be caught and sold according to market conditions when it grows to 7 ~ 10 cm. It can be caught by net or released water, and transported by dry method without water for 36 hours, and the survival rate can reach 90%.
Avoid taking medicine in the shrimp pond in the morning.
Shrimp is a species that is extremely intolerant to hypoxia. In summer, autumn and early morning, the temperature is generally low, especially in the morning after a sultry thunderstorm. Generally, green shrimps are concentrated in the floating head of the pool. If the drug is administered at this time, not only the concentration of the pool water will increase, but also the drug will * * * freshwater shrimp, so that the freshwater shrimp who can't stand the anoxic environmental conditions will suddenly be choked to death by strong drugs. So you can't take medicine in the morning.
So when is the right time to take medicine? Generally, it is more suitable from 10 to around 4 pm. During this period, the dissolved oxygen in the pond is relatively high. As long as the medicine is used properly, there will be absolutely no problem. Observe the activity of freshwater shrimp in time after taking the medicine. If any abnormality is found, add water.
Management method of adult shrimp
In the middle and late stage of a shrimp pond with a body length of 7-8 cm, due to the increase of feeding amount, shrimp manure gradually accumulates, and the joint action of dead algae, residual bait and oxidation and decomposition of organic matter at the bottom of the pond makes great changes in water quality, sediments and microorganisms.
The specific changes of water environment and shrimp in the middle and late stage of shrimp culture are as follows: ph value gradually increases, water color changes from clear green and yellow-green to brown and tea green, transparency decreases and turbidity increases; The bottom of the pool is black and smelly, and the number and species of harmful microorganisms increase; The tail fan and tentacles of prawns are all red, even the tail is rotten and the tentacles are broken. In some shrimp ponds, prawns grow slowly, are weak, have poor sensitivity, fail to shell, are parasitized by ciliates, eat poorly, and have enteritis and yellow gill disease. Some shrimp ponds have symptoms such as swimming, floating head, soft shell, red legs, rotten eyes and crustacean ulcer. Based on many years' experience in shrimp culture, the author summarizes the management points in the middle and late stage of shrimp culture.
Stabilize water color and reduce water turbidity. The main reason for the change of pond water color in the middle and late stage of shrimp culture is the lack of magnesium ions needed for the reproduction and growth of green algae. Dolomite powder can be sprayed for 20-25× 10-6, and used every 7- 10 days/time, which can stabilize water color. In order to reduce the turbidity of water, photosynthetic bacteria 1 0-15×10-6 were used to pour wine all over the pool, and used1time every 7 days. At the same time, the aquaculture water should be disinfected regularly, and the whole pond should be disinfected twice every 10- 15 days. According to the treatment concentration for the first time, dibromohydantoin disinfectant was used in the whole pond in the morning, and organic iodine and quaternary ammonium salt 0.2× 10-6 were used in the whole pond in the second morning. If the turbidity of suspended organic matter in water is high, the concentration of disinfectant can be increased appropriately.
Adjust the balance of nutrients in aquaculture water environment and supplement the contents of calcium, magnesium and phosphorus in water. Every 10- 15 days, 2-3× 10-6 calcium hydrogen phosphate 1 time, 20× 10-6 dolomite powder 1 time.
Improve the bottom environment of the pond and control the ph value. Spraying 0.3x 1 0-16 of beneficial microbial preparation every five days, or spraying1times with zeolite powder as the main raw material every five days, with the dosage of10-15× 60 each time.
Reasonably add water to change water. The water exchange rate should be controlled at about 10 cm on the first day, and gradually increased to 20 cm, 30 cm and 50 cm on the second, third and fourth days. This can not only improve the water quality, but also promote the growth of prawns with shells. If the water level is insufficient, it is necessary to deepen the water level in time and buy oxygen-increasing devices to improve the output and scale of aquaculture. Facts have proved that the higher the shrimp culture yield, the larger the specifications and the more obvious the economic benefits.
Reasonable feeding, reduce feed coefficient. Usually fed four times a day. The feeding time in the morning must be arranged at 1-2 hours after the sun rises, and the best time is that the dissolved oxygen in the water reaches more than 4 mg per liter. Feed every 6 hours 1 time. Control the feeding amount. Generally speaking, it is appropriate for prawns to finish their feed within 45 minutes to 1 hour.
Improve the immune ability and anti-stress ability of prawns. Add: immune polysaccharide 1‰, biological enzyme active additive 2‰, vitamin c 1‰-2‰ and vitamin b 10.5‰ into the feed, and feed it continuously for 2 days a week, with 2 meals a day; The addition of allicin in high temperature season is 0.5‰- 1‰.
Check the health status of prawns regularly. If it is found that prawns eat less or sick prawns float to the side, the infection rate of prawn diseases in general shrimp ponds has reached more than 20%. Therefore, it is necessary to take timely treatment measures for sick shrimp that have been infected but eat normally and have not drifted to the side. In the middle and late stage of prawn culture, 200-300 prawns must be randomly sampled around the pond every 3-5 days to see if they are normal. When prawns suddenly increase or decrease their feed, when the climate changes suddenly, such as after heavy rain and windy weather, after entering the water or changing the water, etc. It is necessary to use rotary net for sampling inspection as soon as possible.