Crab Growth Period Key Management Techniques
The nesting of other fish species is currently based on the mode of raising large crabs (about 500 per acre). In order to make full use of water bodies, 10 to 30 tails of each species can be used for each acre, after the release of crab species. 5 to 7 kilograms of heterotrophic silver carp and 2 to 3 kilograms of green prawns. In addition, from May to the beginning of June, 15 to 30 tails of intensively cultivated carp can be placed at 5 to 7 cm per acre. This is because squid is the main food intake for bottom fish and shrimp. Sets of squid can control wild crabs and shrimps in the crab pool that compete with crabs, fight for oxygen and compete for space.
Pay attention to oyster shell management Before the first oyster shell of the crab, attention should be paid to shallow water breeding, light enhancement, water temperature increase, and early food, feeding small trash fish or high-quality pellet feeds to ensure that the crabs have smooth shells for the first time. Outside the crab pond spilled medicine, fertilization should avoid the relative concentration period of crab shell, while grasping the law of crab shell, forecasting the next peak of the shell. The crab pool disinfection should be performed after changing the water 1 week before the peak of the oyster shell, and add about 1% of locust and (feed grade) calcium dihydrogen phosphate and fructooligosaccharides, vitamin C, Sanhuangsan, etc. in the feed. . The amount of feeding should be reduced during the peak period of clams, and attention should be paid to keeping the environment relatively quiet.
Control crab pond moss suitable for early water, keep the crab pool has a certain degree of fatness, transparency is 30 to 40 cm water depth, weakening the light necessary for moss growth, change before and after the Ching Ming snail into a snail. In the early stages of moss germination, copper sulfate and moss can be used to control the drug, but it is important to pay attention to the effects of moss-killing drugs on the growth of aquatic plants and the timely addition of water the next day after treatment. For ponds with small areas, it is best to remove them manually during the moss growth period.
Maintaining moderate levels of aquatic plants not only provides natural feed for crabs, but also regulates water temperature, provides shelter, absorbs nitrogen, phosphorus, and heavy metals in water bodies, prevents eutrophication and controls water pollution. Crab ponds should be diversified, with submerged plants (Elodea, Vallisneria, etc.) as the mainstay, floating plants (water peanuts, water spinach, green grass, etc.) as supplements, and a small amount of emergent plants (grassroots, reeds) Wait). The distribution of aquatic plants in the crab pool should be sparse and dense, and the water grass coverage should be maintained at 60% to 70% during the crab growth period.
The timely introduction of snails to artificially put snails on the ground not only provides a good source of natural animal protein for river crabs, but also purifies the bottom water bodies. The first time of snail feeding was earlier. Normally, 15 to 200 kg of live snails were released per acre before Chingming to facilitate early adaptability of snails to the pond environment and produce young snails for early feeding. From June to August, it will be recharged 1 time and put in 150-250 kilograms per acre. The two launches will prevent a large amount of disposables, which will cause the early water quality to be thin and the moss will multiply and affect the growth of crabs.
Rational feeding of feed according to the nutritional needs of various stages of crabs with a reasonable mix, requiring before and after the fine, the middle of the green, meat and vegetarian ingredients, Qingjing combination. The ratio of animal and vegetable diets was 60:40 before mid-June, from the late June to mid-August was 45:55, and from mid-late to mid-October was 65:35. When feeding compound feeds, enzyme preparations should be added to the feed to increase exogenous enzyme-assisted digestion. The corresponding increase in feeding points, the main feeding in the evening, so that the feed can be eaten by the crabs in a timely manner, the loss of small waste, pollution is relatively reduced, is conducive to water quality management and disease prevention.
To increase the crab pond oxygen dissolved crab pond to be protected by a reasonable depth of water, the conditions should be installed at the bottom of the micro-tube aeration facility; early stage of regular refilling of new water, 6 to 9 months should increase the amount of water and change the number of water (Sunny afternoon 1 ~ 4 o'clock, early morning rain water injection), the formation of micro-flow of water within a certain period of time, to keep the water fresh; during the rainy season or high temperature season, in addition to conventional influent oxygen, in accordance with changes in water quality in time to cast chemical oxygenation agent (granules Oxygen, Degradation, etc. are generally used in the evening).
Pay attention to the regulation of water quality The transparency of the water body should be maintained at a depth of 30-40 cm before the end of May, and then be maintained at more than 50 cm. From July to August, change the water every 7 to 10 days, each time changing the depth of water by 30 centimeters; from September to October, change the water once a week, changing the water by 1/3 each time. At the same time pay attention to adjust the pH of the water body.
The use of biological agents microbial agents including EM bacteria, photosynthetic bacteria, etc., July to September crab pool to be Quanchiposa 4 times, should be used in the morning of 10 o'clock in the morning on the premise of the start of the aerator, use or after use 1 ~ 2 hours supplemented with particulate oxygen booster (granular oxygen, etc.). Microbiological preparations cannot be used together with disinfectants, antibiotics, etc.
Prevention and control of disease May-June use chloraldihydrochloride for disinfection once, 0.3 grams per cubic meter of water body; From July to September, let crabs take EM microbial preparations, each serving for 3 days; 10 to 11 months before the release of crabs 20 to 25 days can be used to kill ciliate drugs. At the same time, it is necessary to prevent predators, frogs, cockroaches, mice, crawfish, jaundice and birds from attacking.
Smoking Set,E-Cigarette Disposable,Magic Puff Disposable E Cigarette,Healcier Factory Direct
Dongguan Vanilla Bioengineering Co., Ltd. , https://www.healthecigarette.de