Breeding method of scylla paramamosain

Abstract

The breeding method of the scylla paramamosain is characterized by comprising the following steps: S1, breeding seedlings in the south: during the period from the beginning of March to the beginning of May, performing seedling culture of the scylla paramamosain in a southern region of the Yangtze River, and breeding the juvenile crabs in the southern nursery pond to C1-stage juvenile crabs; s2, northern cultivation: in the beginning of May, after the air temperature in the northern area of the Yangtze River rises to 18 DEG C or above, transferring the C1-stage young crabs in the step S1 from the southern nursery pond to a northern cultivation pond in the northern area of the Yangtze River, and performing bait feeding from the beginning of May to the end of September to cultivate the C1-stage young crabs into scylla paramamosain in an adult crab stage; s3, overwintering in the south: loading the scylla paramamosain in the adult crab stage in the step S2 into a transportation device at the end of September, and transporting the scylla paramamosain to an overwintering pond in the south of the Yangtze River for overwintering; according to the method, the effective breeding period from May to September in the northern area is fully utilized, the effective breeding period is an important measure for expanding the breeding space of the scylla paramamosain and increasing the supply amount of the scylla paramamosain, and the breeding benefits of the scylla paramamosain are improved.

Description

Technical Field

[0001] The invention relates to the field of aquaculture, and in particular to a method for culturing mud crabs. Background Art

[0002] The mud crab is mainly distributed in the coastal areas south of the Yangtze River estuary in my country. It has the characteristics of fast growth, strong adaptability, large individuals and high economic value. It is the main economic crab for breeding in my country. In recent years, in order to meet the needs of green and high-quality development of marine aquaculture and marine strategy in my country, many provinces along the southern coast have reduced the pond breeding area of ​​mud crab, resulting in the gradual shrinkage of mud crab breeding. As the breeding capacity is close to the limit, the pond rental cost is high and the mud crab production is in short supply. Therefore, it is urgent to open up new breeding areas to increase the production capacity of mud crabs. The northern coastal areas of Jiangsu and Shandong in my country are rich in seawater resources and a variety of baits. In addition, the coastal mudflats in the north are medium-low saline-alkali areas, which are not suitable for growing crops, so the pond rental is low. However, when breeding in the northern regions with higher latitudes, mud crabs are easily affected by low temperatures. In October, the temperature in the north began to be lower than 18°C, and the mud crabs grew slowly. When the temperature was lower than 9°C, the mud crabs stopped eating. When the temperature was lower than 3-4°C for a long time, the mud crabs began to die. The average temperature in northern my country in winter is 1-4°C, and mud crabs will face the risk of death when they overwinter in the north.

[0003] Therefore, in view of the current situation that the southern coastal areas of my country are facing shrinking aquaculture areas and high pond rental costs, while the northern regions have vast tidal flat aquaculture land and lower pond rental costs, a method for aquaculture of mud crabs with low costs and normal growth by rationally utilizing north and south aquaculture ponds has become an urgent problem to be solved.

[0004] The mud crab needs to go through three stages: juvenile crab stage, sub-adult crab stage and mature stage; in the juvenile crab stage, the crab seedlings have weak immunity and high mortality rate; in the sub-adult crab stage, the mud crab continuously molts and grows, and needs targeted nutrition. Therefore, it is necessary to provide a breeding method that can improve the immunity of crab seedlings and promote the molting and growth of the mud crab. Summary of the invention

[0005] The first technical problem to be solved by the present invention is to provide a low-cost breeding method for mud crabs by reasonably utilizing north-south breeding to enable the mud crabs to grow normally.

[0006] The second technical problem to be solved by the present invention is to provide a method for cultivating mud crabs capable of improving the immunity of crab seedlings in response to the above-mentioned current technical status.

[0007] The third technical problem to be solved by the present invention is to provide a method for cultivating mud crabs that promotes the molting and growth of mud crabs in response to the above-mentioned existing technical status.

[0008] The technical solution adopted by the present invention to solve the first technical problem is: the breeding method of the mud crab is characterized by comprising the following steps:

[0009] S1 Southern seedling cultivation: From early March to early May, after the temperature in the area south of the Yangtze River rises to above 18°C, the seedlings of mud crabs are cultivated in the southern seedling ponds in the area south of the Yangtze River; during the seedling cultivation operation, the water quality parameters of the aquaculture water body in the southern seedling ponds are set to: salinity 25‰~28‰, water temperature 25~27°C, pH7.8~8.2, dissolved oxygen content greater than 7mg / L, ammonia nitrogen concentration less than 0.3mg / L; the light intensity of the southern seedling ponds is 4000~5000lux, and the crab seedlings are cultivated to C1 juvenile crabs in the southern seedling ponds;

[0010] S2 Northern breeding: In early May, after the temperature in the area north of the Yangtze River rises to above 18°C, the C1 stage juvenile crabs of step S1 are transported from the southern nursery pond to the northern breeding pond in the area north of the Yangtze River, and the water quality parameters of the breeding in the northern breeding pond are set to: salinity 13‰-25‰, pH 7.8-8.3, dissolved oxygen content greater than or equal to 5.5mg / L, ammonia nitrogen concentration less than or equal to 0.6mg / L, nitrite nitrogen concentration less than or equal to 0.1mg / L, and the light intensity of the northern breeding pond is 5500-15000lux; feeding the C1 stage juvenile crabs with bait from early May to the end of September to cultivate the mud crabs in the adult crab stage;

[0011] S3 Overwintering in the South: After the temperature in the area north of the Yangtze River drops below 18°C ​​at the end of September, the adult mud crabs of step S2 are loaded on a transport device and transported to the southern overwintering ponds in the area south of the Yangtze River for overwintering. The water quality parameters of the southern overwintering ponds are set as follows: salinity 13‰~25‰, pH7.8~8.3, dissolved oxygen content greater than or equal to 5.5mg / L, ammonia nitrogen concentration less than or equal to 0.6mg / L, nitrite nitrogen concentration less than or equal to 0.1mg / L, and the light intensity of the southern overwintering ponds is 3000~8000lux. Among them, the areas south of the Yangtze River during the southern seedling raising period can be selected from Fujian and Zhejiang provinces; the areas north of the Yangtze River during the northern breeding period can be selected from Jiangsu and Shandong provinces; the areas south of the Yangtze River for overwintering in the south can be selected from Hainan and Guangdong provinces where the temperature is higher.

[0012] The technical solution adopted by the present invention to solve the second technical problem is: the seedling cultivation in step S1 includes applying a water purifier to the southern seedling pool, and the components and amounts of the water purifier applied to the southern seedling pool per cubic meter per day include: 25-30 weight parts of zeolite powder, 20-25 weight parts of vitamin C, and 5-10 weight parts of nitrifying bacteria. Among them, 1 weight part is 0.00625g, and the functions of each component are as follows:

[0013] Zeolite powder has excellent adsorption properties and can absorb organic waste, odor and heavy metal ions in water, keeping the water clean and improving water quality;

[0014] Vitamin C plays a variety of important roles in blue crab breeding. First, it is an antioxidant that helps reduce oxidative stress in the water and protects blue crabs from free radical damage. Second, vitamin C can also enhance the immunity of blue crabs and improve their ability to resist pathogenic microorganisms. In addition, vitamin C can also promote the metabolism and growth and development of blue crabs.

[0015] Nitrifying bacteria can convert ammonia nitrogen in the water into nitrate, thereby reducing the ammonia nitrogen content in the water, reducing the toxic effects of ammonia nitrogen on blue crabs, and maintaining the stability of water quality.

[0016] In order to further improve the water quality, preferably, the water purifier also includes: 15-20 weight parts of ion exchange resin and 3-7 weight parts of Bacillus subtilis. Among them, 1 weight part is 0.00625g, and the functions of each component are as follows:

[0017] Ion exchange resin can remove nitrates in water and nitrates produced by nitrifying bacteria to purify water quality. It also prevents excessive ammonia nitrogen concentration or overload of nutrients such as nitrogen and phosphorus in water bodies, reduces the risk of eutrophication of water bodies, and provides suitable water quality conditions, which is conducive to the healthy growth of blue crabs.

[0018] Bacillus subtilis mainly plays the role of decomposing organic waste and organic matter in the blue crab seedling cultivation process, promoting the degradation and recycling of organic matter in the water body, and helping to maintain the ecological balance of the water body.

[0019] Furthermore, the water purifier includes: 27.5 parts by weight of zeolite powder, 22.5 parts by weight of vitamin C, 7.5 parts by weight of nitrifying bacteria, 17.5 parts by weight of ion exchange resin, and 5 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g, and the ratio of each component in the technical scheme promotes the growth of crab seedlings better than 25 parts by weight of zeolite powder, 20 parts by weight of vitamin C, 5 parts by weight of nitrifying bacteria, 15 parts by weight of ion exchange resin, 3 parts by weight of Bacillus subtilis and 30 parts by weight of zeolite powder, 25 parts by weight of vitamin C, 10 parts by weight of nitrifying bacteria, 20 parts by weight of ion exchange resin, and 7 parts by weight of Bacillus subtilis.

[0020] In order to enhance the heat preservation effect of the southern wintering pool, the southern wintering pool further comprises a pool bottom, a pool wall and a pool roof covering the pool wall, the pool bottom and the pool wall are both provided with a heat preservation layer, and the pool roof is composed of a light-transmitting plate.

[0021] In order to reduce the mortality rate of mud crabs during transportation, the transportation device further comprises:

[0022] A transport box comprises a box, at least one side wall of which is provided with a first vent hole;

[0023] A box body is located in the box body, a sponge layer with seawater is laid on the bottom of the box body, the adult mud crab in step S3 is placed on the sponge layer, the top of the box body is open and covered with a first mesh sheet at the open part, and a second air hole is opened on the side wall of the box body;

[0024] or:

[0025] The transfer operation of step S2 includes the step of transporting to the northern breeding pond through a transfer box, wherein the transfer box includes a transfer box body, wherein a foam box for placing C1 stage juvenile crabs is arranged inside the transfer box body, wherein a sponge layer with seawater is laid on the bottom of the foam box, wherein the top of the foam box is open and covered with a second mesh sheet, wherein the foam box and the transfer box body are provided with vents connected to an external fluid. The provision of the vents allows the mud crabs to breathe during transportation, wherein the sponges with seawater prevent the mud crabs from generating stress due to the bumps during transportation, wherein the seawater also simulates the original living environment of the mud crabs, further reducing stress, and wherein the provision of the first mesh sheet allows ventilation above the box body and within the box body.

[0026] Furthermore, the transfer operation of step S2 includes the step of transporting to the northern breeding pond through a transfer box, the transfer box includes a transfer box body, a foam box for placing C1 stage juvenile crabs is arranged in the box body, another sponge soaked in seawater is laid on the bottom of the foam box, the top of the foam box is open and covered with a second elastic mesh, the second mesh is connected to the foam box, the foam box and the transfer box body are provided with ventilation holes around, and the volume of the C1 stage juvenile crabs accommodated in the foam box accounts for 20% to 30% of the total accommodation space in the foam box. This technical solution avoids the occurrence of overcrowding of the mud crabs in the foam box, and the elasticity of the second mesh allows the capacity of the foam box to be appropriately expanded.

[0027] The technical solution adopted by the present invention to solve the first technical problem is: the feed feeding in step S3 includes the step of feeding in stages, specifically, feeding in three stages:

[0028] C1 stage juvenile crab to sub-adult crab stage: blue crabs weighing ≥0.15g / piece and <25g / piece are fed with feed A, with a feeding cycle from the evening of the current day to the early morning of the next day, with feeding once at 19:00, 24:00 and 5:00 the next day, and the feeding amount each time is 7.5-10g / m 3 ;

[0029] The feed A comprises the following materials in parts by weight: 4 parts by weight of sardines, 3 parts by weight of small scallops, and 3 parts by weight of razor clams;

[0030] Sub-adult to adult stage: Blue crabs weighing ≥25g / piece and <150g / piece are fed with feed B, with a feeding cycle from the evening of the current day to the early morning of the next day, with feeding once at 19:00, 22:00, 2:00 the next day, and 5:00 the next day. The feeding amount each time is 9.375-11.25g / m 3 ;

[0031] The feed B comprises the following materials in parts by weight: 3 parts by weight of anchovies, 3 parts by weight of hawk claw shrimps, 2 parts by weight of soybean cakes, and 2 parts by weight of corn;

[0032] From adult crab to catch stage: Blue crabs with individual weight ≥150g / crab are fed with feed C, with a feeding cycle from the evening of the current day to the early morning of the next day, with feeding once every day at 19:00, 22:00, 2:00 the next day and 6:00 the next day, and the feeding amount each time is 13.125-15g / m 3 ;

[0033] The feed C includes the following materials by weight: 3 parts by weight of sandfish, 3 parts by weight of Japanese shrimp, 2 parts by weight of mussels, and 2 parts by weight of artificial feed for blue crabs. Among them, the feeding scheme at night to early morning fully utilizes the living habits of the blue crabs, which are nocturnal and dormant during the day. Feeding at night can better adapt to their biological clock and behavioral habits, improve appetite and food intake, and improve bait utilization. At the same time, the pool temperature at night is lower than the pool temperature during the day, and the oxygen solubility capacity in the water body is relatively high, which helps to improve the metabolism rate of the blue crabs and promote growth.

[0034] At the same time, feeding according to the nutritional needs of each growth stage can ensure that the blue crabs can get sufficient and appropriate nutrition at different developmental stages, promote growth, enhance physical fitness, improve immunity, reduce the occurrence of diseases, optimize feed utilization efficiency, reduce breeding costs, and improve the overall quality and yield of farmed blue crabs. Specifically:

[0035] During the juvenile stage, the mud crab is in a physiological stage of significantly accelerated growth and periodic molting. The nutritional requirements at this stage are particularly stringent, especially the intake of high-quality protein and key minerals (such as calcium and phosphorus) increases significantly. These nutrients are essential for supporting the rapid construction and reconstruction of its exoskeleton, as well as the development and growth of muscle tissue. Therefore, the selection of scientifically proportioned feeds has become a key factor in promoting the healthy growth of mud crabs. The combination of sardines, small scallops and razor clams included in the feeding plan provides a rich and high-quality source of protein for mud crabs; these proteins are easily absorbed and utilized by the mud crab's digestive system, and can be efficiently converted into bioactive substances, directly participating in and supporting the construction and repair of tissues during its growth process; at the same time, the feed combination is also rich in key minerals such as calcium and phosphorus, which are the main inorganic components of the mud crab shell; by eating these mineral-rich feeds, mud crabs can effectively replenish their mineral reserves in the body, thereby meeting the high demand during the continuous growth and molting of their shells, providing a solid nutritional foundation for the rapid growth and molting of mud crabs in the juvenile stage;

[0036] In the sub-adult stage, blue crabs are in a critical period of continued development and growth. During this stage, the requirements for comprehensive and balanced nutrition are increased, aiming to maintain a high nutritional level to support continuous growth and development. Therefore, the anchovies and hawk claw shrimps included in the combined feeding program provide blue crabs with high-quality protein and fat sources, which help to provide energy and promote the absorption of fat-soluble vitamins. In addition, soybean cake, as a plant protein source, complements animal protein and further enriches the amino acid spectrum of the feed. In addition, corn provides rich carbohydrates, which are important substrates for the energy metabolism of blue crabs and support the energy consumption required for their daily activities and growth and development.

[0037] In the adult crab stage, the physiological focus of the mud crab gradually shifts to the development of the reproductive system and the preparation for reproductive activities. In order to promote the healthy development of the reproductive system and successful reproduction of the mud crab, the combination of sandfish and Japanese shrimp in the feeding plan provides a high-quality protein source for the mud crab. These proteins are not only rich in essential amino acids and support the synthesis of bioactive substances in the mud crab, but also participate in regulating the secretion of reproductive hormones, which has a positive effect on the development of the reproductive system. In addition, the efficient conversion and utilization of proteins also provides mud crabs with sufficient energy reserves to cope with the high energy demand during the reproduction period. Mussels, as part of the feed, not only enrich the nutritional structure of the feed, but also provide rich minerals (such as zinc, selenium, etc.) and trace elements, which are also crucial to the reproductive health of mud crabs. They may participate in regulating the differentiation and maturation of germ cells and promote the improvement of reproductive performance.

[0038] Compared with the prior art, the advantages of the present invention are:

[0039] 1. The coastal areas south of the Yangtze River in my country face the shortage of land for aquaculture ponds and high pond rental costs, while the northern coastal areas north of the Yangtze River in my country are rich in marine aquaculture resources, low pond rental costs, and a wide effective accumulated temperature from May to September, which is suitable for the cultivation of mud crabs. Therefore, the present invention makes full use of the effective cultivation cycle from May to September in the northern region, which is an important measure to expand the cultivation space of mud crabs and increase the supply of mud crabs, thereby improving the cultivation efficiency of mud crabs;

[0040] 2. Starting from October, the temperature in the north begins to be lower than 18°C, and the growth of blue crabs is slow; the average temperature in northern my country in winter is 1-4°C, and blue crabs will face the risk of death in the north during the winter. Therefore, the present invention transports adult crabs to the south of the Yangtze River at the end of September to avoid the phenomenon of increased mortality of blue crabs due to low temperature, thereby improving the survival rate of blue crabs;

[0041] 3. The control of salinity, water temperature, pH, dissolved oxygen content, ammonia nitrogen concentration and light intensity in the southern nursery ponds, northern breeding ponds and southern wintering ponds enables the mud crab to grow and develop better. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below with reference to the embodiments.

[0043] Example 1 A method for cultivating mud crab

[0044] The following is a preferred embodiment of the present invention. The breeding method of mud crabs in this embodiment is mainly used for breeding mud crabs in all stages from crab seedlings to fishing period; the breeding ponds in the south of the Yangtze River in my country are tight, the pond rent is high, but the temperature is high throughout the year; while the breeding ponds in the north of the Yangtze River are numerous and the pond rent is low, but the temperature is only suitable for the growth of mud crabs from May to September. The temperature is lower in spring and winter, generally at 1 to 4°C, which is not conducive to the growth of mud crabs. Heating equipment needs to be provided, which increases the cost. Therefore, it will be beneficial to provide a breeding method of mud crabs that can reasonably utilize the north and south breeding ponds to enable the normal growth of mud crabs and has low cost. The following will expand the detailed steps of the breeding method of mud crabs:

[0045] The breeding method of the mud crab comprises the following steps:

[0046] S1 Southern seedling cultivation: In March 2021, the cultivation of blue crab seedlings was carried out at the Choupijiang Aquaculture Farm in Fenghua District, Ningbo City, Zhejiang Province. During the seedling cultivation period, the water salinity was 25‰~28‰, the water temperature was 25~27℃, pH7.8~8.2, the dissolved oxygen content was greater than 7mg / L, the ammonia nitrogen concentration was less than 0.3mg / L, and the light intensity was 4000~5000lux. 0.5g / m3 of Jinghongqing mixture was added to the seedling pond once a day, and the growth status of the larvae was observed at the same time. The seedlings can emerge when they metamorphose to the C1 stage juvenile crabs. The water quality parameters of the breeding water in the southern seedling pond are preferably set as follows: salinity 18‰, water temperature 26℃, pH8.0, dissolved oxygen content greater than 7mg / L, ammonia nitrogen concentration less than 0.3mg / L; the light intensity in the southern seedling pond is 4500lux; the blue crab seedlings are purchased from the market.

[0047] S2 Breeding in the north: When the temperature in the north rises above 18°C, the C1 juveniles of mud crabs will be transported to the northern coastal areas in acrylic foam boxes for stocking in early May. The breeding conditions of mud crabs in the north are as follows: light intensity: 5500-15000 lux, water temperature: 18°C-32°C, salinity: 13-25, pH: 7.8-8.3, dissolved oxygen: 5.5 mg / L or more, ammonia nitrogen: 0.6 mg / L or less, nitrite nitrogen: 0.1 mg / L or less. The water quality parameters for breeding in the northern breeding ponds are preferably set as follows: salinity 19‰, pH 8.05, dissolved oxygen content greater than or equal to 5.5 mg / L, ammonia nitrogen concentration less than or equal to 0.6 mg / L, nitrite nitrogen concentration less than or equal to 0.1 mg / L, and the light intensity of the northern breeding ponds is 10000 lux;

[0048] S3 Wintering in the South: When the temperature in the north drops below 18℃ at the end of September, the blue crabs in the pond need to be caught and put into breathable plastic boxes and transported by air to the aquatic farm of the Damao Crab Island Breeding Base in Wanning, Hainan (a private breeding farm in Wanning, Hainan) for wintering and fattening. Before the blue crabs winter, the water quality of the southern wintering pond is adjusted to salinity: 13-25, pH: 7.8-8.3, dissolved oxygen: 5.5mg / L or more, ammonia nitrogen: 0.6mg / L or less, nitrite nitrogen: 0.1mg / L or less, light intensity: 3000-8000lux, among which the water quality parameters of the southern wintering pond are preferably set as follows: salinity 19‰, pH 8.05, dissolved oxygen content greater than or equal to 5.5mg / L, ammonia nitrogen concentration less than or equal to 0.6mg / L, nitrite nitrogen concentration less than or equal to 0.1mg / L, and the light intensity of the southern wintering pond is 5500lux.

[0049] The southern wintering pool includes a pool bottom, a pool wall, and a pool roof covering the pool wall. The pool bottom and the pool wall are both provided with insulation layers, and the pool roof is composed of a light-transmitting board. The insulation layer of the pool bottom is a hard foam board, the insulation layer of the pool wall is a black film, and the light-transmitting board is a transparent organic glass board. The temperature in the southern wintering pool is maintained at 22-24℃, which enhances the insulation effect of the southern wintering pool.

[0050] The transport device comprises a transport box and a box body; wherein the transport box comprises a box body, and a first air vent is provided on at least one of the side walls of the box body; the box body is located in the box body, and a sponge layer with seawater is laid on the bottom of the box body, and the adult mud crabs in step S3 are placed on the sponge layer, the top of the box body is open and covered with a first mesh at the open part, and a second air vent is provided on the side wall of the box body; the transfer operation of step S2 comprises the step of transporting to a breeding pond in the north through a transfer box, and the transfer box comprises a transfer box body, and a foam box for placing C1 stage juvenile crabs is provided in the transfer box body, a sponge layer with seawater is laid on the bottom of the foam box, the top of the foam box is open and covered with a second mesh, and air vents connected to an external fluid are provided on the foam box and the transfer box body. The setting of the air holes allows the mud crabs to breathe during transportation. The sponge with seawater prevents the mud crabs from getting stressed due to the bumps during transportation. The seawater also simulates the original living environment of the mud crabs to further reduce stress. The setting of the first mesh allows ventilation on the top and inside of the box.

[0051] The transfer operation of step S2 includes the step of transporting to a northern breeding pond through a transfer box, the transfer box includes a transfer box body, a foam box for placing C1 stage juvenile crabs is arranged in the box body, another sponge soaked in seawater is laid on the bottom of the foam box, the top of the foam box is open and covered with a second elastic mesh, the second mesh is connected to the foam box, the foam box and the transfer box body are all provided with ventilation holes, and the volume of the foam box accommodating the C1 stage juvenile crabs accounts for 20% to 30% of the total accommodating space in the foam box. The technical solution avoids the occurrence of excessive crowding of mud crabs in the foam box, and the elasticity of the second mesh allows the capacity of the foam box to be appropriately expanded, thereby reducing the mortality rate of mud crabs during transportation.

[0052] Comparative analysis of costs and benefits of Example 2 and traditional breeding methods

[0053] 2.1 Traditional breeding methods

[0054] From March 2021 to March 2022, mud crabs were cultured at the Choupijiang Aquaculture Farm in Fenghua District, Ningbo City, Zhejiang Province. The specific steps are as follows: a 5m 3The breeding pond will be put into the seedlings for cultivation in March 2021. During this period, the water quality requirements of the breeding pond are: dissolved oxygen ≥ 5mg / L, pH 7.5-8.5, ammonia nitrogen ≤ 0.2mg / L, nitrite nitrogen ≤ 0.05mg / L, the water temperature is maintained at 15℃-25℃, and the water is changed every two days, with the amount of water changed being one-third of the pond water. Some protein-rich feed, such as fish meat, shrimp meat, etc., is fed every day. The cultivation will end in March 2022, and a breeding cycle will be completed;

[0055] The costs, benefits and profits of the breeding pond and mud crab breeding during the period were recorded respectively. The C1 juvenile crabs at early May 2021 were weighed to obtain the mud crab seedling yield, the adult crabs at the end of September 2021 were weighed to obtain the mud crab breeding yield, the adult crabs at the end of September 2021 were weighed to obtain the mud crab breeding yield, and the overwintering adult crabs at early March 2022 were weighed to obtain the mud crab overwintering yield.

[0056] 2.2 Experimental Results and Discussion

[0057] Table 1 compares the cost, yield, and income of the breeding method of Example 1 and the traditional breeding method of the mud crab from 2021 to 2023. The input cost, yield, income, and profit of the breeding method of Example 1 and the southern breeding, breeding, and traditional breeding methods are calculated based on an area of ​​5 mu for analysis.

[0058] Table 1 Comparative analysis of cost, yield and income of the breeding method of Example 1 and the traditional breeding method

[0059] The breeding method of embodiment 1 Traditional farming methods Input cost (yuan) 45130 94150 Blue crab fry production (kg) 15 10 Blue crab farming output (kg) 300 190 Blue crab wintering production (kg) 200 150 Revenue (Yuan) 426500 335830 Profit (Yuan) 381370 241680

[0060] It can be seen from Table 1 that the blue crab yield, income and profit of the breeding method of Example 1 are significantly higher than those of the traditional breeding method. Specifically, compared with the traditional breeding method, the breeding method of Example 1 has the following advantages: the germination yield, profit, breeding yield and overwintering yield of the blue crab are significantly higher than those of the traditional breeding method, while the input cost is lower than that of the traditional breeding method. Therefore, the breeding method of Example 1 not only solves the problem of shortage of land for blue crab breeding ponds in the south and insufficient blue crab yield, but also makes full use of the idle tidal flat resources in the northern coastal areas, and has significant economic, social and ecological benefits.

[0061] Example 3 Water Purifier Dosage Exploration

[0062] 3.1 Configuration of water purifiers with different component ratios

[0063] 3.1.1 Component 1: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 25 parts by weight of zeolite powder, 20 parts by weight of vitamin C, 5 parts by weight of nitrifying bacteria, 15 parts by weight of ion exchange resin, and 3 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g,

[0064] The method for preparing the water purifier corresponding to component 1 comprises the following steps:

[0065] 1) Weigh 25 g of zeolite powder, 20 g of vitamin C, 15 g of ion exchange resin, 50 g of nitrifying bacteria, and 3 g of Bacillus subtilis to obtain a water purifier powder;

[0066] 2) Pour 68 g of water purifier powder into a clean and sterile container, mix evenly, and then seal and store in a dark place to obtain a water purifier.

[0067] 3.1.2 Component 2 and configuration method

[0068] Component 2: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 27.5 parts by weight of zeolite powder, 22.5 parts by weight of vitamin C, 7.5 parts by weight of nitrifying bacteria, 17.5 parts by weight of ion exchange resin, and 5 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g,

[0069] The method for preparing the water purifier corresponding to component 2 comprises the following steps:

[0070] 3) Weigh 27.5 g of zeolite powder, 22.5 g of vitamin C, 17.5 g of ion exchange resin, 7.5 g of nitrifying bacteria, and 4 g of Bacillus subtilis to obtain a water purifier powder;

[0071] 4) Pour 80 g of water purifier powder into a clean and sterile container, mix evenly, and then seal and store in a dark place to obtain a water purifier.

[0072] 3.1.3 Component 3 and configuration method

[0073] Component 3: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 30 parts by weight of zeolite powder, 25 parts by weight of vitamin C, 10 parts by weight of nitrifying bacteria, 20 parts by weight of ion exchange resin, and 7 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g,

[0074] The method for preparing the water purifier corresponding to component three comprises the following steps:

[0075] 5) Weigh 30 g of zeolite powder, 25 g of vitamin C, 20 g of ion exchange resin, 10 g of nitrifying bacteria, and 7 g of Bacillus subtilis to obtain a water purifier powder;

[0076] 6) Pour 92 g of water purifier powder into a clean and sterile container, mix evenly, and seal the container to avoid light to obtain a water purifier.

[0077] 3.2 Comparative experiment of water purifiers of various components

[0078] In March 2022, blue crab seedlings were raised at Choupijiang Aquaculture Farm in Fenghua District, Ningbo City. Twelve breeding ponds were selected from the farm and numbered 1 to 12. Ponds 1 to 3 were set as experimental group 1, ponds 4 to 6 were set as experimental group 2, ponds 7 to 9 were set as experimental group 3, and ponds 10 to 12 were set as blank control groups; in each pond of experimental group 1, the proportion and application amount of component 1 were applied; in each pond of experimental group 2, the proportion and application amount of component 2 were applied; in each pond of experimental group 3, the proportion and application amount of component 3 were applied spraying; in each pond of the blank control group, no water purifier was sprayed; in early May, the survival rate, molting number, molting cycle, feeding rate and physiological indicators of vitality of the mud crabs in each breeding pond were observed and recorded, among which the vitality was observed by the number of bounces of the larvae. The specific steps of the observation were: use a 500 ml transparent glass beaker to scoop out a cup of water from the breeding pond, and let it stand for 20-40 seconds. The larvae will slowly sink to the bottom of the beaker and then bounce up. The vitality of the larvae can be observed by observing the number of bounces of the larvae in the beaker per minute.

[0079] 3.3 Comparative experimental results

[0080] Table 2 Analysis of the effects of different water purifier contents on the growth and vitality of mud crab

[0081] Experimental Group 1 Experimental Group 2 Experimental Group 3 Blank control group Survival rate <![CDATA[56.33±1.53 b ]]> <![CDATA[66.00±2.65 a ]]> <![CDATA[55.67±1.53 b ]]> <![CDATA[38.24±2.00 c ]]> Shelling quantity <![CDATA[76.33±1.53 b ]]> <![CDATA[83.33±5.51 a ]]> <![CDATA[77.00±1.00 b ]]> <![CDATA[57.00±3.61 c ]]> Shelling cycle <![CDATA[5.67±0.58 b ]]> <![CDATA[3.67±0.58 c ]]> <![CDATA[6.00±1.00 b ]]> <![CDATA[9.43±1.15 a ]]> Feeding rate <![CDATA[80.67±3.79 a ]]> <![CDATA[83.00±1.73 a ]]> <![CDATA[80.33±3.21 a ]]> <![CDATA[65.00±3.00 b ]]> Number of bounces <![CDATA[45.33±2.89 b ]]> <![CDATA[49.67±1.53 a ]]> <![CDATA[44.00±2.00 b ]]> <![CDATA[31.65±2.89 c ]]> Deformity rate <![CDATA[3.67±0.58 b ]]> <![CDATA[2.33±0.58 c ]]> <![CDATA[3.33±1.15 b ]]> <![CDATA[8.67±1.53 a ]]>

[0082] Note: Different superscript letters in the same row indicate significant differences among the groups (P<0.05);

[0083] From the results in Table 2, it can be seen that the physiological indicators of the mud crabs in Experimental Group 1, Experimental Group 2, and Experimental Group 3 are all better than those in the blank control group. Spraying water purifiers in the southern nursery pond of Example 1 can significantly improve the survival rate, molting number, molting cycle, and feeding rate of the mud crab larvae, indicating that water purifiers play an important role in the mud crab breeding process, which is specifically reflected in the following aspects:

[0084] Improve water quality: The zeolite powder, ion exchange resin and other ingredients in Jinghongqing mixture have the functions of adsorption, detoxification and purification of water quality, which can reduce the content of harmful substances in water and provide a clean and healthy growth environment for blue crab larvae;

[0085] Improve immunity: Vitamin C and Bacillus subtilis and other ingredients can enhance the antioxidant capacity and immunity of blue crab larvae, help blue crabs resist the pressure of the external environment, and reduce the risk of disease infection;

[0086] Promote growth and development: The nitrifying bacteria in Jinghongqing mixture help promote the conversion of ammonia nitrogen into nitrates, improve the efficiency of nitrogen cycle in water, provide nutrient support for the growth of blue crabs, shorten the molting cycle, and promote the growth of larvae;

[0087] In addition, through the analysis of Table 4, it can be preliminarily analyzed that the survival rate, molting number, feeding rate and jumping number of the mud crab larvae in pools 4 to 6 are significantly better than those of the other two groups, while the molting cycle and deformity rate are significantly lower than those of the other two groups. Therefore, component 2 has a better effect on the physiological indicators of mud crabs. Therefore, the application amount and ratio of the water purifier are preferably component 2, specifically: the components and amounts of the water purifier applied in each cubic meter of the southern nursery pond every day include: 27.5 parts by weight of zeolite powder, 22.5 parts by weight of vitamin C, 7.5 parts by weight of nitrifying bacteria, 17.5 parts by weight of ion exchange resin, and 5 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g.

[0088] Example 4 Exploration of key components of water purifier

[0089] 4.1 Configuration of water purifiers with different component ratios

[0090] 4.1.1 Component 4: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 30 parts by weight of zeolite powder, 20 parts by weight of vitamin C, and 15 parts by weight of ion exchange resin. Among them, 1 part by weight is 0.00625g,

[0091] The method for preparing the water purifier corresponding to component 4 comprises the following steps:

[0092] 7) Weigh 30 g of zeolite powder, 20 g of vitamin C, and 15 g of ion exchange resin to obtain a water purifier powder;

[0093] 8) Pour 65 g of water purifier powder into a clean and sterile container, mix evenly, and seal the container to avoid light to obtain a water purifier.

[0094] 4.1.2 Component 5 and configuration method

[0095] Component 5: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pond. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pond every day include: 10 parts by weight of nitrifying bacteria and 7 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g,

[0096] The method for preparing the water purifier corresponding to component five comprises the following steps:

[0097] 9) Weigh 10 g of nitrifying bacteria and 7 g of Bacillus subtilis to obtain a water purifier powder;

[0098] 10) Pour 17 g of water purifier powder into a clean and sterile container, mix evenly, and seal the container to avoid light to obtain a water purifier.

[0099] 4.1.3 Component 6 and configuration method

[0100] Component 6: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 30 parts by weight of zeolite powder, 25 parts by weight of vitamin C, 10 parts by weight of nitrifying bacteria, 20 parts by weight of ion exchange resin, and 7 parts by weight of Bacillus subtilis. Among them, 1 part by weight is 0.00625g,

[0101] The method for preparing the water purifier corresponding to component six comprises the following steps:

[0102] 11) Weigh 30 g of zeolite powder, 25 g of vitamin C, and 10 g of nitrifying bacteria to obtain a water purifier powder;

[0103] 12) Pour 65 g of water purifier powder into a clean and sterile container, mix evenly, and seal the container to avoid light to obtain a water purifier.

[0104] 4.2 Comparative experiment of water purifiers of various components

[0105] In March 2021, mud crab seedlings were raised at Choupijiang Aquaculture Farm in Fenghua District, Ningbo City, Zhejiang Province. Nine breeding ponds were selected from the farm and numbered 13 to 21. Ponds 13 to 15 were set as experimental group 4, ponds 16 to 18 were set as experimental group 5, and ponds 19 to 21 were set as experimental group 6. In each pond of experimental group 4, the proportion and application amount of component 4 were applied; in each pond of experimental group 5, the proportion and application amount of component 5 were applied; in each pond of experimental group 6, the proportion and application amount of component 6 were applied. spraying; in each pond of the blank control group, no water purifier was sprayed; in early May, the survival rate, molting number, molting cycle, feeding rate and physiological indicators of vitality of the mud crabs in each breeding pond were observed and recorded, among which the vitality was observed by the number of bounces of the larvae. The specific steps of the observation were: use a 500 ml transparent glass beaker to scoop out a cup of water from the breeding pond, and let it stand for 20 to 40 seconds. The larvae will slowly sink to the bottom of the beaker and then bounce up. The vitality of the larvae can be observed by observing the number of bounces of the larvae in the beaker per minute.

[0106] 4.3 Comparative experimental results

[0107] Table 3 Analysis of the effects of different water purifier contents on the growth and vitality of mud crab

[0108] Experimental Group 4 Experimental Group 5 Experimental Group 6 Survival rate <![CDATA[46.67±1.53 b ]]> <![CDATA[45.00±3.61 b ]]> <![CDATA[53.33±2.08 a ]]> Shelling quantity <![CDATA[67.67±1.15 c ]]> <![CDATA[64.33±1.53 b ]]> <![CDATA[75.00±2.65 a ]]> Shelling cycle <![CDATA[8.47±0.58 a ]]> <![CDATA[8.61±1.00 a ]]> <![CDATA[6.33±1.15 b ]]> Feeding rate <![CDATA[71.67±2.52 b ]]> <![CDATA[70.00±1.73 b ]]> <![CDATA[78.67±2.08 a ]]> Number of bounces <![CDATA[37.67±0.58 b ]]> <![CDATA[38.33±1.53 b ]]> <![CDATA[45.00±1.00 a ]]> Deformity rate <![CDATA[7.47±1.53 a ]]> <![CDATA[7.31±1.24 a ]]> <![CDATA[4.33±0.58 b ]]>

[0109] Note: Different superscript letters in the same row indicate significant differences among the groups (P<0.05);

[0110] From the results in Table 3, it can be seen that the physiological indicators of the mud crab in the experimental group 6 are better than those in the blank control group. Spraying the water purifier in the southern nursery pond of Example 1 can significantly improve the survival rate, molting number, molting cycle and feeding rate of the mud crab larvae.

[0111] Therefore, it can be concluded that zeolite powder, vitamin C and nitrifying bacteria are the main components of water purifiers that promote the physiological indicators of mud crabs.

[0112] Example 5 Exploration of the component ratio of key ingredients of water purifier

[0113] This example explores the ratio of zeolite powder, vitamin C, and nitrifying bacteria obtained in Example 4, with the aim of obtaining a ratio that is beneficial to

[0114] 5.1 Configuration of water purifiers with different component ratios

[0115] 5.1.1 Component VII: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pond. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pond every day include: 25 parts by weight of zeolite powder, 20 parts by weight of vitamin C, and 5 parts by weight of nitrifying bacteria. Among them, 1 part by weight is 0.00625g,

[0116] The method for preparing the water purifier corresponding to component seven comprises the following steps:

[0117] 13) Weigh 25 g of zeolite powder, 20 g of vitamin C, and 5 g of nitrifying bacteria to obtain a water purifier powder;

[0118] 14) Pour 50 g of water purifier powder into a clean and sterile container, mix evenly, and seal it to avoid light to obtain a water purifier.

[0119] 5.1.2 Component 8 and configuration method

[0120] Component 8: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 27.5 parts by weight of zeolite powder, 22.5 parts by weight of vitamin C, and 7.5 parts by weight of nitrifying bacteria. Among them, 1 part by weight is 0.00625g;

[0121] The method for preparing the water purifier corresponding to component eight comprises the following steps:

[0122] 15) Weigh 27.5 g of zeolite powder, 22.5 g of vitamin C, and 7.5 g of nitrifying bacteria to obtain a water purifier powder;

[0123] 16) Pour 57.5 g of water purifier powder into a clean and sterile container, mix evenly, and seal the container to avoid light to obtain a water purifier.

[0124] 5.1.3 Component 9 and configuration method

[0125] Component 9: The seedling cultivation in step S1 of Example 1 includes applying a water purifier to the southern seedling pool. The components and amounts of the water purifier applied to each cubic meter of the southern seedling pool every day include: 30 parts by weight of zeolite powder, 25 parts by weight of vitamin C, and 10 parts by weight of nitrifying bacteria. Among them, 1 part by weight is 0.00625g,

[0126] The method for preparing the water purifier corresponding to component nine comprises the following steps:

[0127] 17) Weigh 30 g of zeolite powder, 25 g of vitamin C, and 10 g of nitrifying bacteria to obtain a water purifier powder;

[0128] 18) Pour 65 g of water purifier powder into a clean and sterile container, mix evenly, and seal the container to avoid light to obtain a water purifier.

[0129] 5.2 Comparative experiment of each component of water purifier

[0130] In March 2022, mud crab seedlings were raised at Choupijiang Aquaculture Farm in Fenghua District, Ningbo City, Zhejiang Province. Nine breeding ponds were selected from the farm and numbered 22 to 30. Ponds 22 to 24 were set as experimental group 7, ponds 25 to 27 were set as experimental group 8, and ponds 28 to 30 were set as experimental group 9. In each pond of experimental group 7, the proportion and amount of component 7 were applied; in each pond of experimental group 8, the proportion and amount of component 8 were applied; in each pond of experimental group 9, the proportion and amount of component 9 were applied. The mixture was sprayed with the following ratios and dosages; in early May, the survival rate, molting number, molting cycle, feeding rate and physiological indicators of vitality of the mud crabs in each breeding pond were observed and recorded. The vitality was observed by the number of bounces of the larvae. The specific steps of the observation were: use a 500 ml transparent glass beaker to scoop out a cup of water from the breeding pond, and let it stand for 20 to 40 seconds. The larvae will slowly sink to the bottom of the beaker and then bounce up. The vitality of the larvae can be observed by observing the number of bounces of the larvae in the beaker per minute.

[0131] 5.3 Comparative Experimental Results

[0132] Table 4: Analysis of the effects of different zeolite powder, vitamins and nitrifying bacteria contents on the growth and vitality of mud crabs

[0133]

[0134]

[0135] Note: Different superscript letters in the same row indicate significant differences among the groups (P<0.05);

[0136] Table 4 shows that experimental group 8 performs better in terms of survival rate, molting number, molting cycle, feeding rate and vitality state. Therefore, it can be concluded that component 8 is the component ratio with the best effect of water purifier on the physiological indicators of mud crab, that is, the components and dosage of water purifier sprayed in each cubic meter of southern nursery pond every day include: 27.5 parts by weight of zeolite powder, 22.5 parts by weight of vitamin C, and 7.5 parts by weight of nitrifying bacteria. Among them, 1 part by weight is 0.00625g.

[0137] Example 6 Night feeding method in northern breeding ponds

[0138] The feeding of the bait in step S3 of Example 1 includes the step of feeding in stages, specifically, feeding in three stages:

[0139] C1 stage juvenile crab to sub-adult crab stage: Blue crab individual weight ≥ 0.15g / piece and < 25g / piece, feed feed A, with the feeding method from the evening of the current day to the early morning of the next day as one cycle:

[0140] The first feeding was at 19:00 every day, and the feeding amount was 8.75g / m 3 ;

[0141] Feed the second time at 24:00 every day, with a feeding amount of 8.75g / m 3 ;

[0142] Feed for the third time at 5:00 the next day, with a feeding amount of 8.75g / m 3 ;

[0143] The mass ratio of sardines, scallops, and razor clams in feed A is 4:3:3;

[0144] From sub-adult to adult crab stage: Blue crabs weighing ≥25g / piece and <150g / piece are fed with feed B. The feeding method for one cycle from the evening of the current day to the early morning of the next day is as follows:

[0145] The first feeding was at 19:00 every day, and the feeding amount was 10.31g / m 3 ;

[0146] The second feeding was conducted at 22:00 every day, with a feeding amount of 10.31 g / m 3 ;

[0147] The third feeding was conducted at 2:00 the next day, with a feeding amount of 10.31 g / m 3 ;

[0148] The fourth feeding was at 5:00 the next day, with a feeding amount of 10.31 g / m 3 ;

[0149] The mass ratio of anchovies: hawk claw shrimp: soybean cake: corn in feed B is 3:3:2:2;

[0150] From adult crab to fishing stage: Blue crabs weighing ≥150g / each are fed with feed C. The feeding method for one cycle from the evening of the current day to the early morning of the next day is as follows:

[0151] The first feeding was at 19:00 every day, and the feeding amount was 14.06g / m 3 ;

[0152] The second feeding was conducted at 22:00 every day, with a feeding amount of 14.06 g / m 3 ;

[0153] The third feeding was conducted at 2:00 the next day, with a feeding amount of 14.06 g / m 3 ;

[0154] The fourth feeding was at 6:00 the next day, with a feeding amount of 14.06 g / m 3 ;

[0155] The mass ratio of sandfish: Japanese shrimp: mussel: blue crab artificial feed in feed C is 3:3:2:2. The ingredients of blue crab artificial feed are: fish meal, squid paste, soybean meal, shrimp meal, beer sauce, lecithin, refined fish oil, high-gluten flour, minerals and trace elements, and vitamins.

[0156] Example 7

[0157] The step of feeding in stages in Example 6 can also be changed to the following steps:

[0158] C1 stage juvenile crab to sub-adult crab stage: Blue crab individual weight ≥ 0.15g / piece and < 25g / piece, feed feed A, with the feeding method from the evening of the current day to the early morning of the next day as one cycle:

[0159] The first feeding was at 19:00 every day, with a feeding amount of 7.5g / m 3 ;

[0160] Feed the second time at 24:00 every day, with a feeding amount of 7.5g / m 3 ;

[0161] Feed for the third time at 5:00 the next day, with a feeding amount of 7.5g / m 3 ;

[0162] The mass ratio of sardines, scallops, and razor clams in feed A is 4:3:3;

[0163] From sub-adult to adult crab stage: Blue crabs weighing ≥25g / piece and <150g / piece are fed with feed B. The feeding method for one cycle from the evening of the current day to the early morning of the next day is as follows:

[0164] The first feeding was at 19:00 every day, and the feeding amount was 9.375g / m 3 ;

[0165] The second feeding was conducted at 22:00 every day, with a feeding amount of 9.375 g / m 3 ;

[0166] Feed for the third time at 2:00 the next day, with a feeding amount of 9.375g / m 3 ;

[0167] The fourth feeding was at 5:00 the next day, with a feeding amount of 9.375 g / m 3 ;

[0168] The mass ratio of anchovies: hawk claw shrimp: soybean cake: corn in feed B is 3:3:2:2;

[0169] From adult crab to fishing stage: Blue crabs weighing ≥150g / each are fed with feed C. The feeding method for one cycle from the evening of the current day to the early morning of the next day is as follows:

[0170] The first feeding was at 19:00 every day, and the feeding amount was 13.125g / m 3 ;

[0171] Feed the second time at 22:00 every day, with a feeding amount of 13.125g / m 3 ;

[0172] Feed for the third time at 2:00 the next day, with a feeding amount of 13.125 g / m 3 ;

[0173] The fourth feeding was at 6:00 the next day, with a feeding amount of 13.125 g / m 3 ;

[0174] The mass ratio of sandfish: Japanese shrimp: mussel: blue crab artificial feed in feed C is 3:3:2:2. The ingredients of blue crab artificial feed are: fish meal, squid paste, soybean meal, shrimp meal, beer sauce, lecithin, refined fish oil, high-gluten flour, minerals and trace elements, and vitamins.

[0175] Example 8

[0176] The step of feeding in stages in Example 8 can also be changed to the following steps:

[0177] C1 stage juvenile crab to sub-adult crab stage: Blue crab individual weight ≥ 0.15g / piece and < 25g / piece, feed feed A, with the feeding method from the evening of the current day to the early morning of the next day as one cycle:

[0178] The first feeding is at 19:00 every day, and the feeding amount is 10g / m 3 ;

[0179] Feed the second time at 24:00 every day, the feeding amount is 10g / m 3 ;

[0180] Feed for the third time at 5:00 the next day, with a feeding amount of 10g / m 3 ;

[0181] The mass ratio of sardines, scallops, and razor clams in feed A is 4:3:3;

[0182] From sub-adult to adult crab stage: Blue crabs weighing ≥25g / piece and <150g / piece are fed with feed B. The feeding method for one cycle from the evening of the current day to the early morning of the next day is as follows:

[0183] The first feeding was at 19:00 every day, and the feeding amount was 11.25g / m 3;

[0184] Feed the second time at 22:00 every day, with a feeding amount of 11.25g / m 3 ;

[0185] Feed for the third time at 2:00 the next day, with a feeding amount of 11.25g / m 3 ;

[0186] The fourth feeding was at 5:00 the next day, with a feeding amount of 11.25 g / m 3 ;

[0187] The mass ratio of anchovies: hawk claw shrimp: soybean cake: corn in feed B is 3:3:2:2;

[0188] From adult crab to fishing stage: Blue crabs weighing ≥150g / each are fed with feed C. The feeding method for one cycle from the evening of the current day to the early morning of the next day is as follows:

[0189] Feed the first time at 19:00 every day, with a feeding amount of 15g / m 3 ;

[0190] Feed the second time at 22:00 every day, with a feeding amount of 15g / m 3 ;

[0191] Feed for the third time at 2:00 the next day, with a feeding amount of 15g / m 3 ;

[0192] Feed the fourth time at 6:00 the next day, with a feeding amount of 15g / m 3 ;

[0193] The mass ratio of sandfish: Japanese shrimp: mussel: blue crab artificial feed in feed C is 3:3:2:2. The ingredients of blue crab artificial feed are: fish meal, squid paste, soybean meal, shrimp meal, beer sauce, lecithin, refined fish oil, high-gluten flour, minerals and trace elements, and vitamins.

[0194] Example 9 Effects of daytime and nighttime feeding methods on growth indicators of sub-adult mud crabs

[0195] 9.1 Experimental procedures

[0196] When the temperature in the area north of the Yangtze River rose to above 18°C ​​on May 1, 2021, the C1 juvenile crabs of Example 1 were transported to the northern breeding pond located in Dongying Haiyue Aquatic Technology Co., Ltd., and 6 breeding ponds were selected and divided into two groups, numbered 31 to 36, respectively, recorded as Experimental Group 9 and Experimental Group 10. Two feeding modes were adopted in the northern breeding ponds. Experimental Group 9 adopted the feeding mode of the daytime feeding group, and Experimental Group 10 adopted the feeding mode of the night feeding. The detailed steps of the two feeding modes are as follows:

[0197] The specific feeding pattern of the daytime feeding group is as follows: In the juvenile crab stage (size 0.15-25g), feed A of Example 6 is fed at 8:00 a.m., 11:00 a.m. and 17:00 p.m., and the feeding amount for each time period is 8.75 g / m 3 In the sub-adult crab stage (size 25-150g), feed B of Example 6 was fed at 8:00 am, 11:00 am, 14:00 pm and 17:00 pm, and the feeding amount for each time period was 10.31 g / m 3 In the adult crab stage (specifications 150g or more), feed C of Example 6 was fed at 8:00 am, 11:00 noon, 14:00 pm and 17:00 pm, and the feeding amount for each time period was 14.06 g / m 3 ;

[0198] The specific feeding pattern of the night feeding group is as follows: In the juvenile crab stage (size 0.15-25g), feed A of Example 6 is fed at 19:00, 24:00 and 5:00 in the morning, and the feeding amount in each time period is 8.75g / m 3 In the sub-adult crab stage (size 25-150g), feed B of Example 6 was fed at 19:00 at night, 22:00 at night, 2:00 in the morning of the next day and 5:00 in the morning of the next day, and the feeding amount for each time period was 10.31g / m 3 In the adult crab stage (specification 150g or more), feed C of Example 6 was fed at 19:00 at night, 22:00 at night, 2:00 in the morning of the next day and 6:00 in the morning of the next day, and the feeding amount for each time period was 14.06g / m 3 ;

[0199] During the cultivation period, the water quality parameters of the northern breeding ponds were set as follows: salinity 13‰ ~ 25‰, pH 7.8 ~ 8.3, dissolved oxygen content greater than or equal to 5.5 mg / L, ammonia nitrogen concentration less than or equal to 0.6 mg / L, nitrite nitrogen concentration less than or equal to 0.1 mg / L, and the light intensity of the northern breeding ponds was 5500 ~ 15000 lux; the adult mud crabs were harvested at the end of September, and the survival rate, body weight, weight gain rate, specific growth rate and fatness rate of the adult mud crabs were measured and recorded.

[0200] 9.2 Comparative Experimental Results

[0201] Table 5 Comparative analysis of growth indicators of the night-feeding group and the day-feeding group of the mud crab

[0202] Experimental Group 10 Experimental Group 9 Survival rate <![CDATA[78.61±2.42 a ]]> <![CDATA[68.47±3.67 b ]]> weight <![CDATA[405.71±11.25 a ]]> <![CDATA[323.21±10.48 c ]]> Weight gain rate <![CDATA[38.57±1.23 a ]]> <![CDATA[30.21±1.25 b <!-- 13 -->]]> Specific growth rate <![CDATA[0.043±0.001 a ]]> <![CDATA[0.037±0.001 b ]]> Fullness <![CDATA[0.32±0.02 a ]]> <![CDATA[0.23±0.01 b ]]>

[0203] Note: Different superscript letters in the same row indicate significant differences among the groups (P<0.05);

[0204] As shown in Table 5, the growth index of the mud crab in the night feeding group was significantly better than that in the day feeding group. The reasons are as follows: mud crabs usually come out to forage at night in the natural environment and hide in caves or mud during the day. The night feeding mode simulates their natural living habits, allowing mud crabs to eat when they are most active, improving the efficiency of food intake. At the same time, night feeding can ensure that most of the food is consumed by mud crabs in a short period of time, reducing the impact of residual food on water quality.

Claims

1. A method for cultivating mud crabs, characterized in that The following steps are included: S1 Southern seedling cultivation: From early March to early May, after the temperature in the area south of the Yangtze River rises to above 18°C, the seedlings of mud crabs are cultivated in the southern seedling ponds in the area south of the Yangtze River; during the seedling cultivation operation, the water quality parameters of the aquaculture water body in the southern seedling ponds are set to: salinity 25‰~28‰, water temperature 25~27°C, pH7.8~8.2, dissolved oxygen content greater than 7mg / L, ammonia nitrogen concentration less than 0.3mg / L; the light intensity of the southern seedling ponds is 4000~5000lux, and the crab seedlings are cultivated to C1 juvenile crabs in the southern seedling ponds; S2 Northern breeding: In early May, after the temperature in the area north of the Yangtze River rises to above 18°C, the C1 stage juvenile crabs of step S1 are transported from the southern nursery pond to the northern breeding pond in the area north of the Yangtze River, and the water quality parameters of the breeding in the northern breeding pond are set to: salinity 13‰-25‰, pH 7.8-8.3, dissolved oxygen content greater than or equal to 5.5mg / L, ammonia nitrogen concentration less than or equal to 0.6mg / L, nitrite nitrogen concentration less than or equal to 0.1mg / L, and the light intensity of the northern breeding pond is 5500-15000lux; feeding the C1 stage juvenile crabs with bait from early May to the end of September to cultivate the mud crabs in the adult crab stage; S3 Overwintering in the South: After the temperature in the area north of the Yangtze River drops below 18°C ​​at the end of September, the adult mud crabs of step S2 are loaded onto a transport device and transported to the southern overwintering ponds in the area south of the Yangtze River for overwintering. The water quality parameters of the southern overwintering ponds are set to: salinity 13‰~25‰, pH7.8~8.3, dissolved oxygen content greater than or equal to 5.5mg / L, ammonia nitrogen concentration less than or equal to 0.6mg / L, nitrite nitrogen concentration less than or equal to 0.1mg / L, and the light intensity of the southern overwintering ponds is 3000~8000lux.

2. The method for cultivating mud crab according to claim 1, characterized in that: The seedling cultivation in step S1 includes spraying a water purifier into the southern nursery pond. The components and dosage of the water purifier sprayed into the southern nursery pond per cubic meter daily include: 25-30 parts by weight of zeolite powder, 20-25 parts by weight of vitamin C, and 5-10 parts by weight of nitrifying bacteria.

3. The method for cultivating mud crab according to claim 2, characterized in that: The water purifier also includes: 15-20 parts by weight of ion exchange resin and 3-7 parts by weight of Bacillus subtilis.

4. The method for cultivating mud crab according to claim 3, characterized in that: The water purifier comprises: 27.5 parts by weight of zeolite powder, 22.5 parts by weight of vitamin C, 7.5 parts by weight of nitrifying bacteria, 17.5 parts by weight of ion exchange resin, and 5 parts by weight of Bacillus subtilis.

5. The method for cultivating mud crab according to any one of claims 1 to 4, characterized in that: The southern wintering pool comprises a pool bottom, a pool wall and a pool roof covering the pool wall. The pool bottom and the pool wall are both provided with a heat preservation layer, and the pool roof is composed of a light-transmitting plate.

6. The method for cultivating mud crab according to any one of claims 1 to 4, characterized in that: The transport device comprises: A transport box comprises a box, at least one side wall of which is provided with a first vent hole; A box body is located in the box body, a sponge layer with seawater is laid on the bottom of the box body, the adult mud crab in step S3 is placed on the sponge layer, the top of the box body is open and covered with a first mesh sheet at the open part, and a second air hole is opened on the side wall of the box body; or: The transfer operation of step S2 includes the step of transporting to the northern breeding pond through a transfer box, wherein the transfer box includes a transfer box body, wherein a foam box for placing C1 stage juvenile crabs is provided inside the transfer box body, a sponge layer containing seawater is laid on the bottom of the foam box, the top of the foam box is open and covered with a second mesh, and ventilation holes connected to the external fluid are provided on the foam box and the transfer box body.

7. The method for cultivating mud crab according to any one of claims 1 to 4, characterized in that: The feeding of the bait in step S3 includes the step of feeding in stages. Specifically, feeding is performed in three stages: C1 stage juvenile crab to sub-adult crab stage: blue crabs weighing ≥0.15g / piece and <25g / piece are fed with feed A, with a feeding cycle from the evening of the current day to the early morning of the next day, with feeding once at 19:00, 24:00 and 5:00 the next day, and the feeding amount each time is 7.5-10g / m 3 ; The feed A comprises the following materials in parts by weight: 4 parts by weight of sardines, 3 parts by weight of small scallops, and 3 parts by weight of razor clams; Sub-adult to adult stage: Blue crabs weighing ≥25g / piece and <150g / piece are fed with feed B, with a feeding cycle from the evening of the current day to the early morning of the next day, with feeding once at 19:00, 22:00, 2:00 the next day, and 5:00 the next day. The feeding amount each time is 9.375-11.25g / m 3 ; The feed B comprises the following materials in parts by weight: 3 parts by weight of anchovies, 3 parts by weight of hawk claw shrimps, 2 parts by weight of soybean cakes, and 2 parts by weight of corn; From adult crab to catch stage: Blue crabs with individual weight ≥150g / crab are fed with feed C, with a feeding cycle from the evening of the current day to the early morning of the next day, with feeding once every day at 19:00, 22:00, 2:00 the next day and 6:00 the next day, and the feeding amount each time is 13.125-15g / m 3 ; The feed C comprises the following materials in parts by weight: 3 parts by weight of sandfish, 3 parts by weight of Japanese shrimp, 2 parts by weight of mussel, and 2 parts by weight of artificial feed for blue crab.

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