To improve the effectiveness of crayfish breeding in ponds

1. The good seedlings should be stocked and stocked with shrimps of the same size, strong in physique, strong in activity, complete in appendages, and free from injury and illness. The size of the stocked shrimp should reach 0.8-1.0 cm, the size of the shrimp should be more than 3 cm, and the stocking density should be reasonable. The stocking specifications in the same pond should be the same. Shrimp stocking method is to first put the shrimp into a plastic basin, slowly add a small amount of pool water to the basin water temperature and pool water temperature similar, and according to the concentration of 3% to 4% to add salt, so that the shrimp seedling bath disinfection 3 ~ 5 Minutes later, slowly plunge into the pool along the edge of the pool. The winter stocking selection is carried out on sunny mornings. Summer and autumn stocking selections are conducted on sunny mornings or on rainy days. When stocking shrimps, they are bathed with 3% to 5% saline for 5 to 10 minutes to kill parasites and pathogenic bacteria. The shrimp species purchased from other places are long separated by long-distance transportation. When stocking, the shrimp species should be soaked in the pool water for 1 minute, then removed and left for 2 to 3 minutes at the poolside. Three times, after letting the shrimp body surface and sucking cavity water absorb enough water, slowly add the shrimp species into the pool, which can increase survival rate of the stocking. In order to make full use of the aquaculture water space, it is possible to stock some species of white squid (carp and squid) with a stocking size of 100 g, tail, and 50 and 100 tails for 667 m2. The reasonable combination of stocking some of the white pods can not only increase the yield per unit area and increase the economic benefits of breeding, but also make full use of the bait resources in the pool and improve the water quality of the pool.

2. The feed is fed to the lobsters of the lobsters, especially animal feeds, and they are greedy and have large food intake. Feed nutrition should be comprehensive, and the amount of feed should be moderate. Insufficient feeding will affect growth and even cause mutual killing. If the amount is too large, feed will be wasted and water quality will be polluted. If the feed is not fully fed, it will cause malnutrition and affect growth. . When high-density culture is conducted, feeding crayfish with compound feed is the main method. When the shrimp seedlings and shrimp are newly introduced into the pond, fertilization and top dressing can be used to cultivate a large number of rotifers, cladocera, copepods and aquatic insects in the aquaculture ponds. Juveniles, etc. for their feeding; juvenile shrimp fed with compound feed protein content should be greater than 30%, adult shrimp feed protein content should be above 26%, fed twice a day, morning and evening feeding 1 time, morning Feed before sunrise and in the evening after sunset, feed in the evening, accounting for 70% of the daily feed. Daily feed is determined based on the total weight of crayfish in ponds. From March to April and after October, the daily feeding amount is 1% to 3%; from May to October, it is the normal growing season of crayfish, and the daily feeding amount is about 5%. Generally, the feeding rate should be higher when the weather is fine. In the case of hot, continuous rainy weather or excessive water quality, less feeding is required; when shrimps are plucked in large quantities, they are fed less, and they are fed more after the oyster shells. Feeding should adhere to the "four principles" principle, namely positioning, quantitative, timing, and qualitative. The amount of feed with a break should be controlled flexibly according to the weather, water temperature, water color and growth of crayfish. It is advisable to eat full, eat, and leave no residual baits.

3. The management of the shell-fishing period is the key moment for the growth of the crayfish. It is particularly important to manage the clams. The following four aspects should be done: The first is to maintain good water quality. Frequently adding fresh water to keep the water fresh and free from contamination, allowing the crayfish to clam in a good water environment can shorten the clam shell time and facilitate the development of the crayfish; the second is to ensure feed nutrition. Every time crawfish loses its shell, it loses a lot of calcium, phosphorus and iron. Therefore, the compound feed should contain calcium, phosphorus, iron and other indispensable components, and the animal and vegetable feeds for feeding aids should be reasonably matched; the third is to plant and maintain aquatic plants. In the rearing ponds, aquatic plants such as Hydrilla verticillata, Elodea and Vallisneria were planted in the culture ponds, and the coverage rate was over 60%. Crayfish like to clamshell in shallow water or grass. The molluscs after the clam shell will be immediately drilled into the water and hide to avoid the same or predators; the fourth is to destroy the enemy pests. The main enemy of crayfish are water mice, frogs, water birds and some fierce carnivorous fish. These animals can prey on crayfish, which is more harmful to the crayfish that are soft after the clam shell and should be promptly taken to eliminate them. For carnivorous fish, it can be rejected by the mouth of the culture pond through the dense mesh filter during the water intake process. Rats can be trapped in rat cages and squirrel cages; for birds, some color bars and scarecrows can be set off by the pool. The most effective way for frogs is to do artificial capture at night. The fifth is to feed medicine baits. During the crawfish clam shell, as little as possible, without chemicals, in the feed to add photosynthetic bacteria, immune polysaccharides, vitamins, dehulling, calcium dihydrogen phosphate, etc., made of bait feeding, can enhance crayfish Physical fitness reduces the occurrence of shrimp disease and promotes the healthy growth of crayfish.

4. Maintaining good water quality and keeping good water quality is conducive to the healthy growth of crayfish. Every 7 to 10 days, add fresh water once, add 20 cm of water each time to keep the water fresh and clean; use lime to disinfect the body of water every 10 to 15 days, and adjust the pH to 7.5 to 8.5. After quicklime is added with water, it is splashed with hot water. The amount of 667 square meters of water is 10 kilograms, which keeps the water quality weakly alkaline; monthly use of photosynthetic bacteria, EM bacteria or sediment modifier and other micro-ecological agents, reduce the pond Ammonia, nitrite, hydrogen sulfide and other harmful substances in the water, improve the quality of water and sediment, the transparency of the pool water control in 35 to 40 cm. Oxygen-enhanced equipment should be turned on at regular intervals to keep the dissolved oxygen in the pool above 5 mg/l. Fishery Science and Technology households in Jinhu County, Jiangsu Province. Wei Ailian, a demonstration farmer of crayfish farming, installed an oxygen-dissolving controller on the oxygen-increasing equipment. According to the oxygen demand of the crayfish, the upper and lower limits were automatically controlled to automatically turn on and off the oxygen-increasing equipment. The dissolved oxygen in the shrimp pond is always maintained at the optimal setting, so that the crayfish can grow well in a comfortable and happy environment. I believe this technology is worthy of widespread application.

5. The quality of good crayfish should strictly comply with the production standards of pollution-free aquatic products. It is forbidden to use illicit drugs and inputs, strengthen the management of feeding, and improve the breeding quality, quality and breeding efficiency of crayfish.

6. After catching the crayfish for 2 months or so, the shrimp body size can reach 50 grams or more. At this time, fishing can be started. Large-size shrimps can be caught and sold for sale, reducing the density of crayfish in the pool. Promotes the rapid growth of small-sized crayfish. Fishing tools include shrimp cages and cages.

RT-PCR Test Reagent Kit Of COVID-19

The novel coronavirus belongs to the β genus. COVID-19 is an acute respiratory infectious disease. People are generally susceptible. Currently, the patients infected by the novel coronavirus are the main source of infection; asymptomatic infected people can also be an infectious source. Based on the current epidemiological investigation, the incubation period is 1 to 14 days, mostly 3 to 7 days. The main manifestations include fever, fatigue and dry cough. Nasal congestion, runny nose, sore throat, myalgia and diarrhea are found in a few cases.
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