Shrimp cultivation techniques
Cultivation methods At present, the culture method of shrimp mantis is different according to the aquaculture process, and can be divided into artificial whole-farming, rearing and rearing. Artificial breeding throughout the course is to raise 2 cm of artificial seed or 3 to 7 cm of natural seedlings, and cultivate them until they are sold. Fertility rearing is the process of cultivating thinner prawn larvae or relatively small prawn puffers into more fatty prawn puffers, or breeding females through overwintering into slaughtered (fertility) prawn pods with a good degree of ovarian development. Storage holdings refer to the purchase of shrimp larvae, which are stored to a certain quantity and transported to live markets or exports in live form to earn regional differences in the temporary storage process. According to the different forms of cultured land, the culture mode of shrimp can be divided into low dam high net culture and earth pond culture. Beaches with low dams and high net culture ponds are generally chosen to be built in relatively small bays and on a relatively flat and flat beach. Its area is 5 to 50 acres, depending on the number of seedlings. The embankment is 0.6m high and 1.0m wide. The bottom of the embankment is flat and slightly inclined towards the heart of the port. The mesh is approximately 4mm in the centerline of the dam (it is not possible to escape from the strength of the stocked larvae of prawns or phase III larvae). Polyethylene mesh phase diagram, and fixed with bamboo and rope; in the fence on the surface of the dam (about 1 meter away from the fence) and then covered with fine mesh net mesh to prevent shrimp escape from the hole; harvest shrimp Previously, a cone net was harvested at the lowest point of the culture pond. The area of ​​farmed earthen ponds is required to be a few mu to several tens mu, the pond dike is 2.0 to 2.5 meters high, and the water depth is 1.5 to 2.0 meters. There is a gate for entering and leaving seawater, which can put dry water in the pool and install anti-escape nets; the bottom of the pond is made of soft soil. Well, there can't be black mud. At present, most of the shrimp ponds can be used for the cultivation of shrimp, but the black mud at the bottom of the pond must be removed. There are many varieties of shrimp, but not all breeds are worth breeding. Generally, they are farmed with large individuals, fast growth, and easy availability of seed and seed, which are highly adaptable to salinity and temperature, and have a high market price. At present, the breeds that have been cultivated in Zhejiang Province are black-spotted shrimp, snap-mouthed shrimp, and shrimp. In addition, the spines of the Guangdong coastal spiny locust cuttlefish and shaggy shrimp shrimp body length are more than 30 cm, the market price and lobster comparable, is also a promising breeding species. There are two sources of seedlings for seed preparation: artificial seedlings and natural seedlings. As the artificial breeding of shrimp meal has not yet reached the production model, seedlings mainly come from natural sea areas. Natural seedlings are mostly captured by fixed-set ups and bottoms, as well as directly in the mudflats. The time for catching should not be too long to prevent seedlings from being injured or killed for a long time. Seedlings and plants can be transported using oxygenated water or moisturizing and dry transport. The transport time is preferably controlled within 10 hours to ensure the survival rate of transportation. When transporting, care should be taken to avoid high temperatures, sun exposure, rain, and wind blows. In hot seasons, transport at night or cooling with ice should be a good choice. If the natural seedlings and the cultured land are located in different sea areas, attention should be paid to whether there is a difference between the water temperature and the salinity, and the difference must be a transitional approach. Shrimp breeding can be carried out throughout the year, and the stocking season is determined mainly based on the cultivation of artificial seedlings and the time of shrimp sprouting in the local sea area. In the Zhejiang coastal area, shrimp seedlings generally appear from April to October; shrimp shrimp seedlings are most likely from April to June, and black spotted shrimp larvae and spiked shrimp larvae sprout from June to August. Although shrimp can naturally winter, but its growth period in the water temperature is higher than 15 °C in spring, summer and autumn. Site Preparation Shrimp Before breeding, the culture pond must be clear pond. Shrimp, although predator ferocious, but it also has natural enemies, such as jellyfish, tigerfish and so on. Therefore, it is necessary to remove its predators and pathogenic sources before stocking. If natural enemies are found in culture, they should be eliminated as much as possible. Clear Pond is generally conducted in accordance with the effective period of the clear pond drug in advance, choose sunny weather, try to dry the pool water at low tide, with a high concentration of quicklime (30010-6) spill; can also be used 20010-6 bleach disinfection. The reasonable density of stocking technology stocks is one of the factors for successful breeding. The stocking densities of shrimp should be based on pond conditions, seed quality and specifications, feed availability, and aquaculture management levels. The general sea catch natural seed individuals are larger, body length is 3 to 6 centimeters above, can be put 5,000 to 7,000 tails/mu; if stocking about 2 centimeters artificial seedlings, the stocking density can be appropriately higher, is 8000 / Mu; If the shrimp phase III phase-seedling juvenile stocking, put the seedling volume of 15,000 to 30,000 walls. In order to make full use of the water body and improve the breeding efficiency, other aquatic products can also be mixed in shrimp ponds. It is advisable to use the fish and shrimps in the middle and upper layers of water and the shellfish cultured in hanging or bream style so as not to compete with the shrimp for the area of ​​the bottom of the earth. When raising seedlings, pay attention to the following issues: differences in temperature and salinity and the quality of shrimp seedlings. Eliminating the difference in temperature and salinity can be used in the method of floating the seedling bag floating in the pool water and adding water gradually. Poor quality can be differentiated according to the shape, vigor, body color and activity status of the shrimp. Good quality shrimp seedlings have strong vitality, bright white color, firm carapace and complete appendages. Diversify without turning or turning white. In order to estimate the survival rate of shrimp seedlings, a certain number of seedlings can be raised in small cages for inspection. Feeding Techniques Since the Phase III facies larvae and prawns of shrimp mantis are widely fed benthic crustaceans, polychaetes, small fish, bivalves, cephalopods, and serpentines, they should be stocked. For artificial seedlings, it is better to cultivate basic baits to prevent growth sickness or death caused by the uncomfortable feeding of artificial baits, so as to increase the survival rate of the stocking; if the stocking individuals have larger natural seedlings, they can adapt to artificiality due to their strong feeding power. Bait, so it is not necessary to cultivate basic bait. Since the diet of the shrimp is mainly animal-based omnivorous, the general aquatic product can also eat. The commonly used bait varieties are small trash fish, shrimp, shellfish, etc., but fresh duckbill turtles are preferred, which can reduce sediment pollution. Feeding needs to be uniform and it is appropriate to feed it every evening. When feeding large-scale fish or shellfish, shellfish must be cut or shredded beforehand. The amount of feed is based on its feeding rate, and is appropriately adjusted according to its individual size and physiological conditions, water temperature, weather conditions, type and freshness of feed, and water quality. Before 7 centimeters in length, the amount of bait is 21% to 40% of the total weight of the mantis shrimp; body length is 8 to 11 centimeters, and the amount of bait is 11% to 20% of the total weight; body length is more than 12 centimeters The amount of bait is about 10% of its total weight. The effect of changes in water temperature on the growth of shrimp shrimp is mainly achieved through the influence of water temperature on its food intake. When the water temperature is lower than 15°C or higher than 32°C, the food consumption is significantly reduced, and the growth is also significantly slowed down. It is necessary to reduce the amount of feeding. If during the spring and summer breeding season, the food intake of the shrimp mantis is also greatly reduced due to reproductive activities, the amount of feeding should also be reduced. In addition, shrimp do not like to eat fresh feed, but also very easy to pollute the water quality and sediment, should try to vote less. The appropriate amount of feed is the guarantee of normal growth of shrimp, and the starvation has a significant impact on the growth of shrimp, and small individuals are more sensitive to starvation than large individuals. The excessive feeding of bait causes the bait to rot and stench, resulting in deterioration of water quality and sediment quality, and a serious threat to the shrimp that depends on the burrowing of bottom mud camp. Therefore, the amount of bait should be strictly controlled, and its feeding condition should be constantly observed. Setting up bait stations and bottom ponds to observe bottom sediments is a commonly used food inspection method. Water quality control The purpose of water quality management in aquaculture is to maintain the water temperature, salinity, dissolved oxygen, transparency, water color, and pond biological density in the aquaculture water within the optimal growth requirements for the cultured species to facilitate breeding of the species. The normal growth, to achieve the purpose of high and stable production. Shrimp larvae are typical intertidal organisms and have a strong tolerance to changes in temperature and salinity. However, when prawn puffers are cultured, their water quality changes due to their high density often require water quality management. The daily water quality management work is: record the water temperature, salinity and dissolved oxygen 1 to 2 times a day. Depending on the water quality in the pond, decide whether to change the water properly. Keep dissolved oxygen above 4 mg/l, and transparency is controlled between 30 and 50 cm. In summer, the pool water level should be increased, and as much water as possible should be changed in the open sea to keep the water temperature within 33°C to prevent the water temperature from being too high and affect the growth or death of the shrimp. When the water temperature is higher than 33°C, there is a clear death phenomenon in shrimp. In the winter, the water level should be deepened, and the water temperature should be too low (<5°C) to freeze to death. Although shrimp mane is widely adaptable to salinity, salinity changes should be paid attention to places where salinity changes greatly. During the breeding period, every 10 to 15 days, 210-6 quicklime can be used to improve water quality and sediment quality. It can also increase the calcium in the water and facilitate the shelling and disease prevention of shrimp. Monitoring and management of shrimp growth rate is faster, under normal conditions, its body length can be increased by 0.9 to 1.0 centimeters every ten days. In general, the growth of the body length of mantis shrimp is faster than that of the later period. During the breeding season, the body length of the female individual no longer grows because the energy it uses is used for gonadal development. After the reproductive period, it can continue to grow. According to experiments, under the same conditions, black-spotted shrimp grow faster than shrimp. The growth measurement is usually performed once every 10 days. The sample site is trapped with cage nets. In order to ensure the accuracy of measurement, each measurement sample requires more than 50 samples. For the estimation of the number of shrimp ponds, it is difficult to use simple methods to calculate the number of ponds because they live in burrows. However, it can be calculated based on the amount of ten days of growth and the amount of feeding, combined with the water quality conditions at that time. In the culture of shrimp mantis, daily management work should be done as follows: (1) Check the blockages regularly for damage and remove any debris or dirt hanging on the net. (2) Check the dam for any loopholes or bursts, and repair it if found. (3) Regularly inspect the feeding situation of shrimp shrimp, sample anatomy, and observe the content of stomach contents. (4) Check the situation of bait, predator, and sediment when ebbing or releasing water. (5) Take a sample every 10 days to measure its growth. If the growth of body length reaches 0.9-1.0 cm or more per ten days, the explanation is normal. If this does not meet this requirement, the cause should be ascertained. (6) Observe the drill habits, shelling habits and other living habits. If it is found that the shrimp do not drill holes during the day, they may be seriously polluted or lack oxygen. (7) Pay attention to weather changes, harbor water quality, etc. If abnormal weather is found, precautions should be taken in time. If red tides and other unclean water are found, it is not advisable to enter the water and enhance oxygenation. After harvesting the shrimp meal to the commercial specifications, it can be sold according to market demand. According to the survey, the market price depends mainly on the individual size of the mantis shrimp, the goodness of the plumpness, and the degree of development of the female gonad (paste). Individuals more than 11 cm in size, good plump shrimp, market sales are smooth; in the breeding season, as long as the female gonad development is good, individuals even smaller (females about 8 cm can be sexually mature), are also popular. Due to the burrowing nature of shrimp oysters, the fishing methods are specific. According to their habits, the following fishing methods are used for culturing prawn oysters: (1) Set net fishing: in the season where the water temperature is 15°C or higher. Fishing with this method is simple and labor-saving, and generally can capture more than 90% of the total. However, this method is only suitable for fishing at low tide in the night, and it is not possible to feed the fish on the night of fishing. Because shrimps have a nocturnal activity and prey on habits, they will inhabit after drilling. The specific method is as follows: first, the cover net is placed in the groove of the water gate, and the gate is opened at the time of ebbing at night, and the pool water is released, and the shrimp gills will flow downstream into the net. After the pool water is drained, the water is re-introduced at high tide, and it is recaptured the next evening. This is repeated. (2) Earthworm net fishing: In the middle and late stages of shrimp rearing, this method should be used for inter-docking or for catching large market hours. If the breeding ponds do not feed bait at the end of the day, it is better to put bait fishing in the ground nets. Dilong Network is a trap-type fixed network, T-shaped. It has many entrances and a sac net, and there are inverted meshes at each entrance. Shrimp pods are difficult to get out of the mouth and the sac nets are arrested. During the operation, the nets were placed in the pond and the shrimps rushed into the net at night when they were out of the hole due to feeding. The next morning, just pour out from the bladder net. A certain number of ground dragon nets are placed for harvesting depending on the amount of demand and area. (3) Dry-land catch: After catching the shrimp larvae that have been caught by the above two methods or the shrimps that have been trapped in winter due to the low water temperature, they have to catch it with a dry pool. The specific method is: first put the pool water dry or pat dry, you can see the bottom of the pool shrimp cave. The U-shaped shrimp mantle cave has two near-circular outlets, one large and one small. Use your feet to get in from the big hole and forcefully squat a few times. The shrimp worms climb out of the small hole. Due to the high density of the cultured animals, the caves often communicated with each other; or when they were overwinter, the caves became "Y" shaped, and the method of using the pedals was not effective. It had to be picked up by other tools. This hole-by-hole capture basically catches the shrimp in the net pool. Mixed other types of fish and shrimp swimming, but at the same time capture, can be used Zhangtao net fishing; if not harvested, should not put dry pool water, should be collected several times, or choose several fishing methods mixed.
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