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First, the preparation of cultivation ponds Air-raid shelter requirements are closer to the natural sea area, and the natural sea area should choose the area where the seawater is fresh and pollution-free, and there is no large-scale freezing in winter. The salinity of seawater is always between 25‰ and 33‰, and other seawater physicochemical factors. To adapt to the growth requirements of sea cucumber seedlings.
The air-raid shelters have a length of 60m--70m and a width of 2m. There are 2 indoor rooms with an area of ​​15m2, of which one is built as a sedimentation tank and the effective water volume is 18 cubic meters. Three cement pools were built in the corridors inside the shelters. The effective water volume of each cement pool ranges from 8 cubic meters to 12 cubic meters, which amounts to 32 cubic meters. In order to prevent the pool wall of the newly built cement pool from returning alkali, it is required to add fresh water for immersing for 1 month to 2 months before use, and the dry pool water shall be put in place before the seedlings are released, and fresh seawater shall be added after the disinfection and cleaning.
Second, pre-release preparations will be natural seawater into the precipitation tank, the outlet using a 300-mesh sieve filtration seawater. Pool water can achieve the purpose of warming and heat preservation through the unique characteristics of the air-raid shelter.
The attached equipment mainly uses a 40-mesh polyethylene white mesh bag with a size of 30 cm x 40 cm. According to the amount of 80 bags per cubic meter of water --100 bags hanging in the pool water, the net bag is not exposed to the water surface as the standard, evenly distributed in the cultivation pool pool of water on the upper, middle and lower. The mesh bag must be soaked in 20ppm potassium permanganate solution for 2 hours before use.
Third, the seedlings breeding sea cucumber seedlings growth water temperature range of adaptation between 5 °C - 19 °C, when buying seedlings should choose a clean, non-mucus body, the body does not stretch naturally, no clusters, and spine spikes no ulceration After the feeding, the stools became dry and healthy.
The sea cucumber seedlings enter the pond in early December, when the natural seawater temperature is 10°C-10.5°C, and the water temperature in the cultivation pond is 12°C. There are 300,000 young juveniles in the pond, the largest individual is 3 cm in length, and the youngest individuals are juveniles that are not discolored. The specifications are 6000 heads/kg--8000 heads/kg. The seedlings were diluted and evenly sprinkled on the mesh bag. The stocking density was about 10,000 heads/cubic meters.
Fourth, the feed feed of sea cucumber seedlings The breeding of feed mainly depends on feeding artificial compound feed, and appropriate to add marine floating mud, dried scallop powder and so on. The amount fed depends on the temperature of the water, the degree of juvenile ginseng activity, the amount of food consumed, and the amount of remaining bait. The daily feed is generally between 1% and -3% of the total weight of the sea cucumber seedlings. . Before sowing, the feed should be immersed, filtered and sprinkled uniformly on various parts of the cultivating tank, and fed once a day before dusk.
V. Daily management
1. Because the water temperature is low, the physical and chemical factors of seawater in the cultivation pond are basically stable, so the water exchange volume is gradually reduced. The water temperature is changed by 1 time before the water temperature is 9°C, and the water change amount is between 1/3 and 1/2. Change the water one time every other day; If the water temperature is lower than 6°C, change the water every two days. The water temperature in the precipitation tank is maintained between 6°C and -11°C, while the incubation water temperature is maintained between 7°C and -11°C. No sand filtration and heating equipment was added throughout the cultivation process.
2. Oxygenation Due to the high cultivation density of sea cucumbers, the oxygen consumption of juveniles in the metabolic process increases, resulting in a decrease in dissolved oxygen in the water. Individuals are prone to abnormalities. Therefore, continuous oxygenation is used throughout the cultivation process. Breeding, generally can be controlled in the aeration volume of 30L/h cubic meters -40L/h cubic meters.
3. The sea cucumber seedlings cultivated by pouring pools into the pool, due to the daily feed artificial feed, resulting in increased bait and feces daily, a long time will lead to pool bottom black, water quality deterioration, so to keep the water fresh, every 15 days -20 days to pour the pool in time. The original pool should be disinfected with potassium permanganate solution, flushed with clean water and reused. At the same time, abnormal seedlings were found to be strictly rejected to prevent infection of other normal seedlings. When conditional, the seedlings can be screened each time and the seedlings can be cultivated according to the size of the seedlings, which promotes the rapid growth of the sea cucumber seedlings, thereby increasing the survival rate.
4. Disease prevention and control mainly adopts the principle of prevention and prevention and control in the prevention and control of diseases. Through the quality requirements of the purchased seedlings and the strict management during the cultivation period, 2ppm oxytetracycline is used regularly during the cultivation, and after dilution, the whole pool is splashed, which can effectively control the occurrence of bacterial diseases.
Breeding Techniques of Seeds of Sea Cucumber in Air-raid Tunnel
At present, with the increase of the market price of sea cucumber, the scale of breeding in the coastal areas has been continuously expanding, and the demand for seedlings of sea cucumber has increased significantly. In order to increase the survival rate of sea cucumber seedlings in the breeding industry, it is particularly important to cultivate large-sized seedlings. In order to solve the current seawater aquaculture demand for large-sized sea cucumber seedlings, and in order to reduce the cost of raising wintering seedlings and increase economic efficiency, the author used a vacant air-raid shelter (tunnel) to take sea cucumbers in December 2002. Seedlings for wintering cultivation techniques have achieved significant economic benefits.