A method for intensive cultivation of large-sized Penaeus monodon fry in chloride-type saline-alkali water medium in mid-latitude regions

Abstract

The present invention belongs to the field of aquaculture, and specifically relates to a method for intensive seedling rearing of large-sized Penaeus monodon in chloride-type saline-alkali water medium in mid-latitude regions. The method includes steps such as the design and construction of intensive seedling rearing ponds, preparations before fry stocking, fry stocking, intensive rearing management, feeding management, bottom substrate management, growth detection, disease prevention and control, thinning and grading of fry, etc. The present invention makes full use of chloride-type saline-alkali ponds in mid-latitude regions. By building a multi-arch greenhouse, the cost is reduced and the firmness is enhanced; various nutrient salts in the soil are used to cultivate beneficial bacteria to decompose the organic matter generated by residual baits and feces, improving the self-purification ability of the pond; biological baits are inoculated and cultivated before fry stocking, reducing the bait cost and improving the immunity of the prawns; attachment substrates are set up to increase the attachment area of juvenile prawns, reducing the probability of fry cannibalism and increasing the survival rate of intensive seedling rearing. The present invention has low breeding cost, effectively increases economic benefits, and is of great significance for increasing export earnings and solving labor employment, etc.

Description

Technical Field

[0001] The present invention belongs to the field of aquaculture, and particularly relates to a method for culturing and thickening fry of large-sized Penaeus monodon in a chloride-type saline-alkali water medium in mid-latitude regions. Background Art

[0002] Penaeus monodon is also known as ghost shrimp, grass shrimp, and giant tiger prawn. The parent stock of this shrimp is the wild Penaeus monodon from Africa. It has a wide salinity tolerance, can tolerate high temperatures and low oxygen, has relatively strong disease resistance, and a relatively firm body shell. It is the largest prawn in size and is also one of the very important prawn aquaculture varieties in China, being very suitable for large-scale aquaculture.

[0003] In 2005, on the basis of overcoming the technical problems of large-scale fully artificial cultivation of Penaeus monodon broodstock, the South China Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences launched research on Penaeus monodon breeding. After years of efforts, a breeding technology system for Penaeus monodon has been established, and a new variety of Penaeus monodon "South China Sea No. 1" and multiple stress-resistant new strains have been cultivated. In recent years, Haiyi Aquatic Seedling Co., Ltd. in Hainan and Zhanjiang has carried out 9 batches of Penaeus monodon seedling production practices and tracking. The results show that the use of ecological seedling cultivation technology plays an important role in cultivating high-quality, healthy, and efficient fry. The continuous development in seedling cultivation has laid a foundation for the aquaculture of Penaeus monodon.

[0004] In recent years, Deng Jipeng, Huang Jianhua, etc. from the South China Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences have studied the formation conditions and application effects of bioflocs in the aquaculture of Penaeus monodon. The results prove that bioflocs have good effects on the aquaculture of Penaeus monodon. Yang Jing, Guan Chongwu, etc. have studied the construction and operation test of a Penaeus monodon recirculating aquaculture system and obtained good economic benefits. These studies provide a theoretical basis and technical support for the aquaculture of Penaeus monodon.

[0005] Regions such as Guangdong, Fujian, and Hainan are the main areas for Penaeus monodon seedling cultivation and aquaculture in China. Various technologies such as intensive cultivation in high-level ponds, polyculture of fish and shrimp, pond and recirculating water aquaculture are becoming increasingly mature and continuously improving. The area is continuously expanding, and the aquaculture benefits are prominent, being very popular among shrimp farmers. In recent years, northern regions such as Cangzhou in Hebei, Suizhong and Huludao in Liaoning, and Weifang in Shandong have also successively introduced Penaeus monodon for semi-saline water pond aquaculture and facility aquaculture tests, but most of them have only scratched the surface and ultimately failed to form large-scale aquaculture.

[0006] Most waters in the mid-latitude regions are rich in water resources, with a vast area suitable for fishing. It has a temperate climate with obvious seasonal changes, and there is more precipitation in the coastal areas. Many mid-latitude regions have become the main production areas for Litopenaeus vannamei farming due to their superior water source advantages. In recent years, Litopenaeus vannamei farming has faced numerous difficulties, with high rates of pond failure and empty ponds. Coupled with the endless emergence of extreme weather caused by the El Niño phenomenon, the water temperature can exceed 36°C during the high-temperature season, making it increasingly difficult to raise Litopenaeus vannamei. Penaeus monodon has gradually become an alternative variety to Litopenaeus vannamei. Due to the climate characteristics of the mid-latitude regions, the temperature rises slowly in spring. The suitable time for shrimp farming each year is from mid-late May to mid-October, and only one season of farming can be carried out each year. Moreover, because the farming time is short, the farming specifications of shrimp are also restricted. Therefore, the economic benefits of outdoor pond farming cannot be maximized. Therefore, studying the seedling thickening technology of Penaeus monodon in mid-latitude regions and integrating and promoting the farming technology can effectively improve the farming success rate and pond utilization rate, explore a practical way for double-season or large-scale farming in outdoor ponds, realize the maximum and optimal economic benefits of shrimp farming, increase the income of fishermen, help fishermen get rich, and provide scientific and technological support for promoting rural revitalization, which is of great significance. Summary of the Invention

[0007] According to the climate characteristics of the mid-latitude regions and aiming at the short shrimp farming time in this region, this invention conducts seedling thickening through greenhouse earthen ponds to solve the technical problems existing in the large-scale cultivation of Penaeus monodon in mid-latitude regions. The purpose is to provide a seedling thickening technology for shrimp, which innovates significantly in the technological process and methods, and provides an effective way to reduce risks, costs, improve quality and efficiency for shrimp seedling cultivation.

[0008] To achieve the above purpose, the technical scheme adopted by this invention is as follows:

[0009] A method for thickening Penaeus monodon seedlings in mid-latitude regions, characterized by comprising the following steps:

[0010] 1. A method for thickening Penaeus monodon seedlings in chloride-type saline-alkali water medium in mid-latitude regions, characterized by comprising the following steps:

[0011] (I) Design and construction of seedling thickening ponds

[0012] 1. Build a greenhouse using an earthen pond, and design a double-span or multi-span greenhouse structure above the pond;

[0013] 2. Equipment supporting: Equip each pond with 1 blower, lay 1 nano-aeration disk at the bottom per 5m 2 Set an operation platform in the middle of each span, and install a waterwheel aerator at each corner of each greenhouse to form a circular flow to collect sewage in the middle of the pond; Equip a reservoir according to the ratio of 1:1 between the thickening shed and the reservoir;

[0014] (II) Preparation before stocking

[0015] 1. Mix seepage water from the water source pond (or the Yellow River water) with underground brackish well water. The water quality indicators are pH value of 7.5 - 8.6 and salinity of 15 - 20.

[0016] 2. Drain the water in the pond of the fry rearing shed, dredge the silt at the bottom of the pond, level the slope, and sun the pond.

[0017] 3. Cultivate water in the reservoir

[0018] (1) The salinity of the inlet water body is 15 - 20, and the water level is raised to more than 200 cm.

[0019] (2) Disinfect the water body with 2 ppm of 50% potassium peroxymonosulfate. After 12 hours, add Bacillus spp. and EM bacteria microecological agents to adjust the bacterial phase.

[0020] (3) Fertilize the water. In the morning on sunny days, sprinkle and inoculate Chlorella or Oocystis spp., 1 kg of low-temperature water-fertilizing paste and 1 kg of calcium-magnesium enzyme fertilizer per mu, and at the same time add 1 - 3 kg of lactic acid bacteria to fertilize the pond multiple times; make the water transparency reach 40 cm.

[0021] 4. Reserve live bait for larvae

[0022] Soak and flush the pond of the fry rearing shed with 2 ppm of 50% potassium peroxymonosulfate for disinfection, let in 100 cm of water, and heat up to more than 25 °C for standby.

[0023] 5. Place the attachment base Set the attachment base horizontally 25 cm above the bottom of the pond, with 90 - 120 per mu.

[0024] (III) Seedling stocking

[0025] 1. Seedling selection Stock three-forked seedlings with a body length of more than 0.7 cm in mid-April. They are of uniform size, smooth and transparent all over, have good ability to swim against the current, and are sensitive to external stimuli.

[0026] 2. Water testing The survival rate of the three-forked seedlings after 72 hours of water testing is more than 95%.

[0027] 3. Preparations before stocking Start the aerator to stir the water 2 hours before stocking. Sprinkle multi-acid organic acid for detoxification and compound vitamins for anti-stress 1 hour in advance, and calcium-supplementing products such as ionic calcium or Quick Supplement 100; when the water temperature is above 25 °C, conduct transitions of water temperature, salinity, etc. to prevent stress.

[0028] 4. Stocking density 500 - 600 tails / m 2 ;

[0029] 5. Stocking method Stop the impeller aerator and continue to run the blower; soak the seedling bag in water for 10 minutes for temperature transition, then untie the bag mouth, pour in pond water, and lift the bottom of the seedling bag after 3 minutes to pour the water and shrimp seedlings into the pond.

[0030] (4) Management during the intensive cultivation stage

[0031] 1. Feeding management:

[0032] (1) Feeding live bait After releasing the three-pronged seedlings, for the first 3 days, the main food source is the rotifers in the pond. After three days, cladocerans should be fed in a timely manner, with 2 feedings per day, 5 - 8 g / 10,000 tails / time, and fed continuously for 5 days. Adjust the amount appropriately according to the feeding situation of the shrimp larvae;

[0033] (2) Feeding intensive cultivation feed Supplementary feeding of special compound feed is carried out within 5 days after releasing the seedlings, with 2 feedings per day and a feeding amount of 2 g / 10,000 tails / day. After 5 days of releasing the seedlings, feed 5 times a day, with a feeding amount of 8 - 10 g / 10,000 tails / day. Adjust the amount appropriately according to the feeding situation of the shrimp larvae;

[0034] (3) Nutritional supplementation Regularly mix and feed nutritional agents to aid digestion and absorption;

[0035] 2. Water quality management:

[0036] (1) Adding and changing water Starting from the 5th day, add 5 cm of new water every day, gradually increasing from 5 cm and gradually adding it back to the original water level on the same day. 30 minutes before adding water in the first 10 days, sprinkle 0.5 ppm of stress nutrients. The maximum amount of water change at one time can reach 30 cm. If the water quality deteriorates, water can be changed 2 times a day; Starting from the 16th day, drain the sewage every day, and arrange the sewage discharge time to be carried out 1 hour after sunrise or after feeding every day;

[0037] (2) Salinity adjustment Reduce the pond salinity by adding and changing water to adapt to the water quality of the low-salinity waters in the outer pond;

[0038] 3. Management of algal and bacterial communities Inoculate chlorella or oocystis to form dominant algal species and inhibit the reproduction of harmful algae such as cyanobacteria and dinoflagellates;

[0039] 4. Bottom substrate management:

[0040] Use biological bottom improvement agents and 50% potassium persulfate at 0.3 - 0.45 ppm to alternately improve the bottom substrate;

[0041] 5. Growth detection:

[0042] Measure the biological indicators of penaeid shrimp every ten days to guide the adjustment of water quality and the increase or decrease of feed feeding amount;

[0043] 6. Disease prevention and control:

[0044] (1) Vibrio disinfection Disinfect and inhibit the reproduction of vibrio after releasing the seedlings until they are out of the pond; Regularly detect the vibrio content in the seedlings and water body;

[0045] (2) Water body disinfection Before releasing the seedlings, disinfect the water quality with 1 ppm of potassium peroxymonosulfate in a large dose, and use 0.25 ppm of "biological disinfectant bacterial powder" every time after adding water;

[0046] (3) Nutrition fortification is carried out by cross-mixing amino fiber, ionic calcium, and lactic acid bacteria into the feed; after 10 days of fry pre-growing, feed a liver-protecting product three times a day to assist in getting through the liver transformation period.

[0047] (4) Microscopic examination Examine the shrimp fry under a microscope every 3 to 5 days.

[0048] (5) Stress reduction Before water change, sprinkle an anti-stress product, and the water change should be carried out by slowly adding water; it is strictly prohibited for rainwater to flow into the fry pre-growing shed, causing drastic changes in water temperature, pH, and other water quality factors; the increase in feed feeding amount should be gradual.

[0049] (6) Pathogen detection of fry Before separating the fry into ponds, take samples of the fry for detection. After passing the detection, continue with the next stage of cultivation.

[0050] (V) Thinning and separating fry

[0051] After about 30 days of pre-growing, the size of the prawns reaches 3 - 4 cm, and use a cage to catch them for thinning or selling.

[0052] Furthermore, for the facility conditions in step (I) 1. Design and construction of the fry pre-growing pond, the area of the earthen pond for fry pre-growing is 3 - 5 mu, and the water depth is more than 150 cm.

[0053] Furthermore, for the facility conditions in step (I) 1. Design and construction of the fry pre-growing pond, the bottom structure of the earthen pond is sandy loam.

[0054] Furthermore, for the facility conditions in step (I) 1. Design and construction of the fry pre-growing pond, a double-span or multi-span greenhouse structure is designed above the pond. The single-span of the greenhouse is 20 - 25 meters, and the height of the greenhouse above the pond embankment is 2.0 - 2.2 meters.

[0055] Furthermore, for the facility conditions in step (I) 1. Design and construction of the fry pre-growing pond, for the said greenhouse, a double-layer greenhouse film structure is designed through movable card slots on the plastic steel frame. At the same time, install an electric rolling insulation quilt on the top layer. Doors and windows are provided at the bottom of the four sides of the greenhouse, and card slots are set at the doors and windows so that the plastic film of the doors and windows can be removed at any time.

[0056] Furthermore, for the preparations before fry stocking in step (II) 3. Reserve of live fry food 10 days before fry stocking, inoculate rotifers and cladocerans in the greenhouse, and feed marine yeast and bacillus to breed live food.

[0057] Furthermore, for the preparations before fry stocking in step (II) 1. Water source Adjust the sodium-potassium ion ratio in the water body to 28 - 30:1 using potassium chloride, and complex heavy metals in the water body with 10 ppm of EDTA-2Na.

[0058] Further, for the preparation before fry stocking in step (2), the attachment substrate is placed horizontally 25 cm above the pond bottom. The attachment substrate is a cuboid frame with a side length of a steel wire with a diameter of 5.5 mm, a length and width of 100 cm each, and a height of 65 cm. Starting from 25 cm above the pond bottom, a layer of polyethylene large-mesh netting is fixed every 20 cm with a polyethylene thin string at the height fixing knots. The large-mesh netting is 5-mesh 3-strand polyethylene large-mesh net, and the height fixing knots are outwardly convex spot-welded joints.

[0059] Further, for the management during the nursery stage in step (4), in the management of algal and bacterial communities, carbon sources and beneficial bacteria including but not limited to Bacillus spp., Lactobacillus spp., photosynthetic bacteria, and EM bacteria are supplemented every 5 - 7 days to increase the carbon-nitrogen ratio in the water body to 12 - 15:1.

[0060] Further, in the feeding management (3) of the nutrition addition step in the management during the nursery stage in (4), the nutritional agents are multivitamins, Lactobacillus spp., astaxanthin, Chinese herbal medicines for protecting the liver and gallbladder, ionic calcium, and Clostridium butyricum.

[0061] Beneficial effects:

[0062] 1. Penaeus monodon grows and lives in seawater. The seepage water in saline-alkali land and underground brine have great differences in composition from seawater, and juvenile shrimp cannot survive when put into this water. The present invention enables the juvenile shrimp to survive and grow normally by oxidatively degrading and complexing harmful components and adjusting the ion content and ratio.

[0063] 2. The present invention uses the built multi-arch greenhouse, which has a low cost, improves the wind resistance, enhances the firmness, improves the ecological conditions of the shrimp culture pond, and increases the pond culture efficiency. Doors and windows are provided at the bottom around the greenhouse. The plastic films of the doors and windows can be loaded and unloaded at any time through the card slots. When the temperature is low in the early stage, double-layer plastic films and heat-insulating quilts can be covered on the top. As the temperature rises in the later stage, one layer of plastic film and heat-insulating quilt can be removed through the card slots, and at the same time, the plastic films of the doors and windows can be removed to adjust the air temperature and water temperature in the greenhouse. Using the greenhouse earthen pond for fry nursery can effectively utilize various nutrient salts in the soil, cultivate beneficial bacteria, degrade the organic matter generated by the accumulation of feces and residual baits during the cultivation process, improve the self-purification ability of the pond, and also adapt to the ecological habits of Penaeus monodon, facilitating the shrimp to dive to the bottom.

[0064] 3. A polyethylene net attachment substrate is horizontally arranged 25 cm above the pond bottom, enabling the shrimp fry to shuttle up and down through the netting. After feeding, they search for food at the pond bottom and return to the netting to perch after completing the feeding activity, increasing the attachment area of juvenile shrimp, reducing the density at the pond bottom, decreasing the probability of cannibalism among fry, and increasing the survival rate of nursery.

[0065] 4. Before releasing the fry, inoculate and cultivate live baits to enhance the immunity of the penaeid shrimp, reduce production costs, and improve the survival rate of the fry. At the same time, it is also beneficial to enhance the disease resistance and immunity during the later cultivation period. Before changing the water, sprinkle anti-stress products such as multi-vitamins and calcium supplements to avoid rapid temperature changes. When adding water after changing the water, it should be done slowly; the increase in the feed feeding amount should be gradual to avoid stress reactions caused by excessive feeding that leads to gluttony of the fry.

[0066] 5. The aquaculture method of the present invention has low production costs, effectively increases economic benefits, and is of great significance for increasing foreign exchange earnings through exports and solving labor employment, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 It is a schematic diagram of the construction of a multi-arch greenhouse for the intensive cultivation of Penaeus monodon fry of the present invention;

[0068] Figure 2 It is a schematic diagram of the structure of the attachment base;

[0069] In the figure: 1 - pond; 2 - entrance door to the greenhouse; 3 - greenhouse frame; 4 - column; 5 - operation access path; 6 - water collection trough; 7 - multi-arch column; 8 - doors and windows; 9 - attachment base frame; 10 - large-mesh netting; 11 - netting height fixing knot. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0070] The technical solution of the present invention will be further described in detail below through embodiments, but the protection scope of the present invention is not limited in any form by the embodiments.

[0071] Example 1:

[0072] A method for intensive cultivation of Penaeus monodon fry in mid-latitude regions, which comprises the following steps:

[0073] (I) Design and construction of the pond for intensive cultivation of fry

[0074] 1. Construction of the greenhouse: Use a 3 - 5 mu earthen pond to build a greenhouse with a water depth of more than 150 cm. The slope of the pond is protected with geotextile. The bottom structure of the earthen pond is sandy silt. The drainage outlet is located at the lowest point in the center of the pond bottom for convenient sewage discharge and fry collection. A double-span or multi-span greenhouse structure is designed above the pond. The greenhouse is framed with plastic steel and covered with plastic film on top. A double-layer plastic film structure is designed through movable card slots, and at the same time, an electric rolling shutter thermal insulation quilt is installed on the top layer. Doors and windows are provided at the bottom of the four sides of the greenhouse. Through the card slots at the doors and windows, the plastic film of the doors and windows can be loaded and unloaded at any time. In the early stage when the temperature is low, the top can be covered with double-layer plastic film and thermal insulation quilt. In the later stage as the temperature rises, one layer of plastic film and thermal insulation quilt can be removed through the card slots, and at the same time, the plastic film of the doors and windows can be removed to adjust the air temperature and water temperature inside the greenhouse.

[0075] As Figure 1As shown in the figure, the bottom structure of pond 1 is sandy sediment and is not hardened. The entrance door 2 to the shed and the bottom doors and windows 8 around are equipped with card slots. As the temperature rises, the plastic film of the doors and windows can be removed at any time. The shed frame 3 is designed as a double-span or multi-span greenhouse structure, and the single-span of the greenhouse is controlled within 20 - 25 meters. The height of the shed above the pond embankment is limited to 2.0 - 2.2 meters by columns 4. A double-layer greenhouse film structure is designed through movable card slots on the plastic-steel frame, and at the same time, an electric rolling insulation quilt is installed on the top layer. When the temperature is low in the early stage, the top can be covered with a double-layer plastic film or the top insulation quilt. In the later stage, as the temperature rises, one layer of film and the insulation quilt can be removed through the card slots. The operation path 5 is used for feeding, applying drugs, etc. The rainwater on the shed flows out from both ends through the water collection trough 6, reducing pollution and the pressure on the shed. The continuous arch columns 7 connect the multi-span greenhouse structure.

[0076] As Figure 2 shown in the figure, in the figure, the attachment base frame 9 is a square frame made of 5.5mm diameter steel wire, with a length and width of 100cm each and a height of 65cm. The large-mesh netting 10 is a 5-mesh 3-strand polyethylene large-mesh net, and the large-mesh netting has three layers: upper, middle, and lower. The netting height fixing knot 11 starts from 25cm above the bottom of the pond, and at intervals of 20cm, small iron wires are spot-welded to make fixing knots, and a layer of polyethylene large-mesh netting is fixed at the fixing knots with polyethylene thin ropes.

[0077] 2. Facility matching: Each pond is equipped with 1 Roots blower of 3 - 5.5KW, and 1 nano aeration disk is laid per 5m 2 bottom. The aeration disks are updated every year. An operation platform is set in the middle of each span, and a waterwheel aerator is installed at the four corners of each shed to form a circular flow to collect sewage in the middle of the pond. The storage pond is equipped in a ratio of 1:1 with the fry rearing shed.

[0078] (2) Preparations before fry stocking

[0079] 1. Water source: The water source of the farm is the peripheral seepage interception ditch of a large plain reservoir with an area of 6000 mu nearby. The perimeter is 4000m, the upper width is 10m, and the water depth is 1.7 - 2.0m. The reservoir area is located in a saline-alkali waterlogged area. The salinity of the seepage water in the ditch varies seasonally in the range of 3.4 - 4.5, the pH value is 7.8 - 8.1, the total alkalinity is 300 - 320mg / l, and the total hardness is 1000 - 1050mg / l. The salinity of the deep well water is 26 - 30, the pH value is 7.5, the total alkalinity is 350mg / l, and the total hardness is 9500mg / l.

[0080] 2. Pond cleaning: The water in the fry rearing shed is drained dry, the bottom sludge is dredged and the slopes are leveled, and the pond is sunned during winter.

[0081] 3. Water cultivation in the storage pond

[0082] (1) The inlet water utilizes the seepage water of saline-alkali land and underground saline water, adjusts the salinity of the water body to 15-20, raises the water level to more than 200 cm, adjusts the sodium-potassium ion ratio of the water body to 28-30:1 with potassium chloride, and complexes heavy metals in the water body with 10 ppm of EDTA-2Na.

[0083] (2) Water body disinfection: Disinfect the water body with 2×10 ～6 Disinfect the water body with 50% potassium peroxysulfate. After 12 hours, add probiotics such as Bacillus spp. and EM bacteria to adjust the bacterial phase.

[0084] (3) Fertilize the water: On sunny mornings, sprinkle and inoculate Chlorella or Oocystis, 1 kg of "low-temperature water-fertilizing paste" and 1 kg of "calcium-magnesium enzyme fertilizer" per mu, and at the same time add 1-3 kg of lactic acid bacteria to fertilize the pond multiple times; make the transparency of the water body reach 40 cm.

[0085] 4. Reserve live bait for larvae

[0086] Soak and flush the nursery pond with 2 ppm of 50% potassium peroxysulfate, fill it with 100 cm of water, heat it up to more than 25 °C for standby; 10 days before stocking the seedlings, inoculate a certain amount of rotifers and cladocerans in the greenhouse, and feed marine yeast and Bacillus spp. to breed live bait to reserve high-quality animal bait for the shrimp larvae after they enter the greenhouse.

[0087] 5. Place the attachment base: Horizontally set 3 strands of polyethylene large-mesh nets 30 cm above the bottom of the pond to increase the attachment area of juvenile shrimps and reduce cannibalism during the molting period.

[0088] (III) Seedling stocking

[0089] 1. Seedling selection: Stock three-pronged seedlings with a body length of more than 0.7 cm in mid-April. The sizes are uniform, the whole body is smooth and transparent, they can swim against the current well, and are sensitive to external stimuli. Conduct a stress resistance test out of water if necessary. Microscopic examination shows no red or black spots, no parasites, no fouling, etc. on each part.

[0090] 2. Water testing: The survival rate of the three-pronged seedlings after 72 hours of water testing is more than 95%.

[0091] 3. Preparation before stocking: Turn on the aerator to stir the water 2 hours before stocking, sprinkle polybasic organic acid to detoxify and compound vitamins to resist stress 1 hour in advance, and use calcium supplement products such as ionic calcium or quick supplement 100; when the water temperature is above 25 °C, conduct transitions of water temperature, salinity, etc. to prevent stress.

[0092] 4. Stocking density: 500-600 tails / m 2 。

[0093] 5. Stocking method: Stop the impeller aerator and continue to run the blower. Soak the seedling bag in water for 10 minutes for temperature transition, then untie the bag mouth, pour in pond water, and lift the bottom of the seedling bag after 3 minutes to pour the water and shrimp seedlings into the pond.

[0094] (4) Management during the intensification period

[0095] 1. Feeding management:

[0096] (1) Feeding of live bait After releasing the three-fork seedlings, within the first 3 days, the main food source for the shrimp is rotifers in the pond. After three days, cladocerans should be fed in a timely manner, twice a day, at a rate of 5 - 8 g / 10,000 tails per feeding, and fed continuously for 5 days. Adjust the feeding amount appropriately according to the feeding situation of the shrimp fry.

[0097] (2) Feeding of intensification feed Supplementary feeding of special formulated feed is carried out within 5 days after releasing the seedlings, twice a day, at a feeding rate of 2 g / 10,000 tails per day. After 5 days of releasing the seedlings, feed 5 times a day, at a feeding rate of 8 - 10 g / 10,000 tails per day. Adjust the feeding amount appropriately according to the feeding situation of the shrimp fry.

[0098] (3) Nutritional supplementation Regularly mix and feed amino red fiber (0.3%), astaxanthin (0.1%), Chinese herbal medicine for protecting the liver and gallbladder (0.1%), ionic calcium (0.5%), and Clostridium butyricum (0.2%) to aid digestion and absorption.

[0099] 2. Water quality management:

[0100] (1) Adding and changing water Starting from the 5th day, add 5 cm of new water every day, gradually increasing from 5 cm and gradually adding it back to the original water level on the same day. 30 minutes before adding water in the first 10 days, sprinkle 0.5 ppm of stress nutrients. The maximum one-time water change can reach 30 cm. If the water quality deteriorates, water can be changed twice a day; starting from the 16th day, drain the sewage every day, and arrange the sewage discharge time 1 hour after sunrise or after feeding every day.

[0101] (2) Salinity adjustment Reduce the pond salinity by adding and changing water to adapt to the water quality of the low-salinity water area in the outer pond.

[0102] 3. Management of algal and bacterial communities Inoculate Chlorella or Oocystis to form a dominant algal species, inhibiting the reproduction of harmful algae such as blue-green algae and dinoflagellates; regularly supplement carbon sources and beneficial bacteria (Bacillus, Lactobacillus, photosynthetic bacteria, EM bacteria, etc.) to increase the carbon-nitrogen ratio in the water body to 12 - 15:1, forming biological flocs and controlling the concentrations of ammonia nitrogen and nitrite in the water body within a safe range.

[0103] 4. Substrate management:

[0104] Use biological bottom improvement agents and 50% potassium peroxymonosulfate at 0.3 - 0.45 ppm to alternately improve the bottom, and note that when using biological bottom improvement agents, it must be carried out 12 hours after using potassium peroxymonosulfate in the water body.

[0105] 5. Growth detection:

[0106] Measure the biological indicators of penaeid shrimp every ten days to guide the adjustment of water quality and the increase or decrease of feed feeding amount;

[0107] 6. Disease prevention and control:

[0108] (1) Vibrio disinfection: After stocking, use "Bacteriophagy King" to kill the Vibrio carried by the seedlings. Every 4 days, "Bacteriophagy King", "Biological Disinfectant Powder" and "Targeted Phage Water Quality Improver" will be used to inhibit the reproduction of Vibrio until the seedlings are released from the pond. Regularly test the Vibrio content in the seedlings and water bodies to achieve total control and prevention first.

[0109] (2) Water Disinfection Before stocking, the water quality should be disinfected with a large dose of 1ppm potassium persulfate, and 0.25ppm "biological disinfectant powder" should be added after each water addition.

[0110] (3) Nutritionally fortified multivitamins (mixed with 50kg feed / 500g), ionized calcium (mixed with 20kg feed / 500g), and lactic acid bacteria (mixed with 50kg feed / 1000ml) are cross-mixed in the feed; after 10 days of seedling coarsening, the feed is mixed with liver protection products 3 times a day to help the fish survive the liver transition period.

[0111] (4) Microscopic examination: Inspect shrimp fry every 3 to 5 days, including abnormalities in the hepatopancreas (full and clear shape, yellowish brown in color, with a white capsule), intestinal tract (thick, full and uninterrupted); body surface (smooth without dirt, thick shell), attached branches (no parasites, pigmentation), etc.; check the composition of unicellular algae in the water every 3 days. Pond water dominated by diatoms, green algae, and cryptoalgae is high-quality water for cultivation. Check whether there are cyanobacteria, flagellates, naked algae, etc. in the water that may cause abnormal water quality and their proportion, and take timely measures to regulate and control.

[0112] (5) Reduce stress. Sprinkle multivitamins, calcium supplements and other anti-stress products before changing water, avoid rapid changes in water temperature, and do not fill the water quickly after changing water. Add water slowly. It is strictly forbidden for rainwater to flow into the seedling shed, causing drastic changes in water temperature, pH and other water quality factors, causing strong stress to the seedlings. The increase in feed feeding amount should be gradual to avoid a sharp increase in the feeding amount, which may cause the seedlings to overeat and have a stress response.

[0113] (6) Pathogen detection of seedlings Before the seedlings are divided into ponds, the seedlings are sampled and tested. The main test indicators are shown in Table 2. The seedlings of four brands were sent to the Quality Inspection Department of Bohai Aquatic Products Co., Ltd. for testing of designated pathogens. All the results were negative, so they can continue to the next stage of breeding.

[0114] (V) Thinning and dividing seedlings

[0115] After about 30 days of thickening, the shrimps reach a size of 3 to 4 cm and can be caught with ground traps for thinning or sale.

[0116] (VI) Economic Benefits

[0117] The economic benefits of the intensive cultivation of Penaeus monodon fry are shown in Table 1. The survival rate of the intensive cultivation of Penaeus monodon is 85%. 1.02 million juvenile shrimps with a body length of 3-4 cm are sold, with an average selling price of 1,800 yuan per 10,000 shrimps, and the total output value is 183,600 yuan.

[0118] Table 1. Cost accounting of the intensive cultivation of Penaeus monodon fry

[0119]

[0120] Table 2 Detection indexes of common diseases of Penaeus monodon fry

[0121] Test Items and Indicators Standard Test Method WSSV (White Spot Syndrome Virus) Negative PCR-Fluorescent Probe Method IHHNV (Infectious Hypodermal and Hematopoietic Necrosis Virus) Negative Multiplex PCR Detection Method AHPND (Acute Hepatopancreatic Necrosis Disease) Negative PCR-Fluorescent Probe Method EHP (Enterocytozoon hepatopenaei) Negative PCR-Fluorescent Probe Method

[0122] The present invention can be carried out in brackish water and semi-brackish water in the mid-latitude regions of China. It can be used for the intensive cultivation of large-sized Penaeus monodon fry in mid-latitude regions, and can also be used for the intensive cultivation of fry for the double-season or multi-season cultivation of Penaeus monodon in mid-latitude regions. By building a multi-arch earthen pond greenhouse, inoculating and cultivating biological baits, setting attachment substrates, and carrying out large-sized cultivation across years or double-season or multi-season cultivation, the pond farming benefits can be doubled.

[0123] Although exemplary embodiments of the present invention have been described for the purpose of illustration, those skilled in the art will understand that various changes, such as modifications, additions, and substitutions, can be made in form and detail without departing from the scope and spirit of the invention disclosed in the appended claims. All such changes should fall within the protection scope of the appended claims of the present invention, and each part of the product and each step in the method claimed by the present invention can be combined in any combination form. Therefore, the description of the embodiments disclosed in the present invention is not intended to limit the scope of the present invention, but to describe the present invention. Accordingly, the scope of the present invention is not limited by the above embodiments, but is defined by the claims or their equivalents.

Claims

1. A method for large-scale nursery of Penaeus monodon fry in chloride-type saline-alkali water medium in mid-latitude regions, characterized in that, It includes the following steps: (1) Design and construction of the nursery pond for fingerling thickening 1. Greenhouse construction: Use the earthen pond to build a greenhouse, and design a multi-span greenhouse structure above the pond; 2. Facility supporting: One blower is equipped for each pond, and one nano-aeration disk is laid at the bottom per 5m 2 One operation platform is set in the middle of each span, and waterwheel aerators are installed at the four corners of each shed to form a circular flow to collect sewage in the middle of the pond; The water storage pond is equipped in the ratio of 1:1 of the seedling rearing shed to the water storage pond; (2) Preparation before fry stocking 1. Water source: The pond seeps water or mixes the Yellow River water with the underground brackish well water. The water quality index has a pH value of 7.5 - 8.6 and a salinity of 15 - 20; 2. Pond cleaning: Drain the water in the thickening shed pond, dredge and level the slope of the pond bottom sludge, and sun the pond; 3. Water cultivation in the reservoir (1) Water inlet: The salinity of the water body is 15 - 20, and the water level is raised to more than 200 cm; (2) Water body disinfection: Disinfect the water body with 2 ppm of 50% potassium peroxymonosulfate. After 12 hours, add Bacillus and EM bacteria microecological agents to adjust the bacterial phase; (3) Fertilizing the water: On sunny mornings, sprinkle and inoculate Chlorella or Oocystis, 1 kg of low-temperature water-fertilizing paste per mu, 1 kg of calcium and magnesium enzyme fertilizer per mu, and at the same time add 1 - 3 kg of lactic acid bacteria to fertilize the pond multiple times; make the water transparency reach 40 cm; 4. Reserve of live bait for larvae Soak and wash and disinfect the thickening shed pond with 2 ppm of 50% potassium peroxymonosulfate, fill it with water to 100 cm, and heat it to above 25 °C for standby; 5. Placement of attachment substrates: Horizontally set the attachment substrates 25 cm from the bottom of the pond, 90 - 120 per mu; (3) Fry stocking 1. Fry selection: Stock the three-pronged fry with a body length of more than 0.7 cm in mid-April. They are of uniform size, smooth and transparent all over, have good ability to swim against the current, and are sensitive to external stimuli; 2. Water testing: The survival rate of the three-pronged fry after 72 hours of water testing is more than 95%; 3. Preparation before fry stocking: Turn on the aerator to stir the water 2 hours before fry stocking, sprinkle multi-acid organic acid to detoxify and compound vitamins to anti-stress 1 hour in advance, and use ionic calcium or quick supplement 100 calcium supplement products; when the water temperature is above 25 °C, carry out water temperature and salinity transition to prevent stress; 4. Stocking density: 500 - 600 tails / m 2 ; 5. Fry stocking method: Stop the impeller aerator from working, and continue to operate the blower; soak the fry bag in water for 10 minutes for temperature transition, then untie the bag mouth, pour in the pond water, and lift the bottom of the fry bag after 3 minutes to pour the water and shrimp fry into the pond; (4) Management during the thickening period 1. Feeding management: (1) Feeding of live bait: After stocking the three-pronged fry, in the first 3 days, mainly feed on rotifers in the pond. After three days, feed cladocerans in time, feed 2 times a day, 5 - 8 g / 10,000 tails·time, and feed continuously for 5 days, and appropriately increase or decrease according to the feeding situation of the shrimp fry; (2) Feeding of thickening feed: Assist in feeding the special formulated feed within 5 days after fry stocking, feed 2 times a day, the feeding amount is 2 g / 10,000 tails·day. After 5 days of fry stocking, feed 5 times a day, the feeding amount is 8 - 10 g / 10,000 tails·day, and appropriately increase or decrease according to the feeding situation of the shrimp fry; (3) Nutritional addition: Regularly add nutritional agents to aid digestion and absorption; 2. Water quality management: (1) Adding and changing water: Start adding 5 cm of new water every day from the 5th day, gradually increase from 5 cm, and gradually add it to the original water level on the same day. Sprinkle 0.5 ppm of stress nutrient 30 minutes before adding water in the first 10 days. The maximum one-time water change can reach 30 cm. If the water quality deteriorates, change the water 2 times a day; Start draining sewage every day from the 16th day, and arrange the sewage draining time 1 hour after sunrise or after feeding every day; (2) Salinity adjustment: Reduce the salinity of the pond by adding water and changing water to adapt to the water quality of the low-salinity waters in the outer pond.

3. Management of algal and bacterial communities: Inoculate Chlorella or Oocystis to form dominant algal species and inhibit the reproduction of harmful algae such as cyanobacteria and dinoflagellates.

4. Substrate management: Use biological bottom modifiers and 50% potassium persulfate at 0.3 - 0.45 ppm to alternately improve the bottom.

5. Growth monitoring: Measure the biological indicators of the shrimp every ten days to guide the adjustment of water quality and the increase or decrease of feed feeding amount.

6. Disease prevention and control: (1) Vibrio disinfection: Disinfect after stocking the fry to inhibit the reproduction of Vibrio until the shrimp are harvested; regularly detect the Vibrio content in the fry and water body. (2) Water body disinfection: Disinfect the water quality with 1 ppm of potassium peroxyhydrogen sulfate at a high dose before stocking the fry, and add 0.25 ppm of "biological disinfectant powder" after each water addition. (3) Nutritional enhancement: Cross-mix feed with amino red fiber, ionic calcium, and lactic acid bacteria; after 10 days of fry nursery, mix feed with liver-protecting products three times a day to help the shrimp through the liver transformation period. (4) Microscopic examination: Examine the shrimp fry under a microscope every 3 - 5 days. (5) Stress reduction: Sprinkle anti-stress products before changing water, and change water at a rate of slow water addition; strictly prohibit rainwater from flowing into the fry nursery shed to avoid drastic changes in water temperature, pH, and other water quality factors; increase the feed feeding amount gradually. (6) Detection of fry pathogens: Conduct sampling tests on the fry before pond separation, and continue the next stage of cultivation after passing the test. (V) Thinning and sorting of fry After about 30 days of nursery, when the shrimp reach a size of 3 - 4 cm, use a fish trap to catch and thin or sell the shrimp. In the management of the nursery period in step (IV) 3. Management of algal and bacterial communities, supplement carbon sources and beneficial bacteria every 5 - 7 days, including but not limited to Bacillus spp., Lactobacillus spp., photosynthetic bacteria, and EM bacteria, to increase the carbon-nitrogen ratio in the water body to 12 - 15:

1. In the nutritional addition step of the feeding management in (IV) 1. Feeding management, the nutritional agents are amino red fiber, astaxanthin, Chinese herbal medicines for protecting the liver and gallbladder, ionic calcium, and Clostridium butyricum.

2. The method for intensive cultivation of large-sized Penaeus monodon fry in chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, In the design and construction of the fry nursery pond in step (I), the area of the earthen pond for fry nursery is 3 - 5 mu, and the water depth is more than 150 cm.

3. The method for intensive cultivation of large-size Penaeus monodon fry in the chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, In the design and construction of the fry nursery pond in step (I), the bottom structure of the earthen pond is sandy mud.

4. A method for intensive cultivation of large-size Penaeus monodon fry in chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, In the design and construction of the fry nursery pond in step (I), a multi-span greenhouse structure is designed above the pond. The single-span of the greenhouse is 20 - 25 meters, and the height of the greenhouse above the pond embankment is 2.0 - 2.2 meters.

5. A method for nursery rearing of large-size Penaeus monodon fry in chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, In the design and construction of the fry nursery pond in step (I), for the greenhouse, a double-layer greenhouse film structure is designed through movable card slots on the plastic steel frame, and an electric rolling shutter thermal insulation quilt is installed on the top layer. Doors and windows are provided at the bottom of the four sides of the greenhouse, and card slots are set for the entrance door and doors and windows so that the plastic film of the doors and windows can be removed at any time.

6. The large-scale nursery method for Penaeus monodon in a chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, In the preparation before stocking in step (II) 4. Reserve of live fry food: Ten days before stocking, inoculate rotifers and cladocerans in the greenhouse and feed marine yeast and Bacillus spp. to breed live food.

7. A method for culturing and thickening larvae of large-sized Penaeus monodon in chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, In the preparation before stocking in step (II) 1. Water source: Adjust the sodium-potassium ion ratio in the water body to 28 - 30:1 with potassium chloride, and complex heavy metals in the water body with 10 ppm of EDTA-2Na.

8. A method for intensive cultivation of large-size Penaeus monodon fry in chloride-type saline-alkali water medium in mid-latitude regions according to claim 1, characterized in that, Preparation before stocking in step (2): The attachment base is placed horizontally 25 cm above the bottom of the pond. The attachment base is a cuboid frame with a side length of 100 cm in length and width and a height of 65 cm, made of steel wire with a diameter of 5.5 mm. Starting from 25 cm above the bottom of the pond, a layer of polyethylene large-mesh netting is fixed every 20 cm at the height fixing knots with polyethylene thin ropes. The large-mesh netting is 5-mesh 3-strand polyethylene large-mesh net, and the height fixing knots are outward convex spot welding points.

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