Method for promoting egg carrying of scylla paramamosain

Abstract

The application belongs to the technical field of Scylla paramamosain, and particularly relates to a method for promoting Scylla paramamosain to hold eggs. The method comprises the following steps: domesticating Scylla paramamosain by using water bodies with the same salinity as that of the water bodies in a pond for breeding Scylla paramamosain; stimulating the domesticated Scylla paramamosain by using low-temperature and low-salinity water bodies; and inducing the stimulated Scylla paramamosain by using high-temperature and high-salinity water bodies. The Scylla paramamosain is sequentially domesticated, stimulated and induced, and the sudden change of water temperature and salinity is continuously controlled, so that the Scylla paramamosain can efficiently hold eggs.

Description

Technical Field

[0001] The present application belongs to the technical field of mud crabs, and specifically relates to a method for promoting the spawning of mud crabs. Background Art

[0002] The mud crab (Scylla paramamosain) is a marine crab of the genus Scylla in the family Portunidae. It is rich in protein and trace elements such as calcium, phosphorus, iron, and zinc, which are very nourishing to the body. Traditional Chinese Medicine believes that it has the effects of tonifying the kidneys, eliminating stagnation, strengthening the spleen, nourishing the heart, and calming the nerves. Artificial propagation of Scylla paramamosain seedlings involves fattening and spawning crabs, rearing larvae, and cultivating young crabs. The timing of obtaining spawning crabs and the number and quality of spawning crabs directly determine the time and yield of artificial seedlings, which in turn affects the subsequent benefits of mud crab farming.

[0003] Currently, the primary method for obtaining spawning crabs during seedling rearing is to allow roe crabs to spawn naturally in rearing ponds. However, since spawning behavior is affected by both physiology and the environment, obtaining high-quality roe crabs in the right quantity and at the right time is difficult. Previous studies have used methods used in fish and other crustacean seedling rearing to induce spawning, such as cutting the roe crabs' eyestalks and injecting them with oxytocin, to induce spawning, with some success. However, these procedures are labor-intensive and technically demanding, and mechanical damage to the parent crabs after these procedures can easily lead to infection by pathogens, making these techniques difficult to implement widely in production. Researchers have also employed methods used in shellfish seed rearing to induce spawning by drying and exposing temporarily fattened roe crabs. However, drying and exposing them can harm roe crabs already in the rearing ponds. Furthermore, some roe crabs may even ovulate during drying and exposing, resulting in wasted roe crabs. Summary of the Invention

[0004] Based on the production needs and the growth and reproduction rules of the mud crab, this application promotes its efficient spawning by controlling the sudden changes in water temperature and salinity during the cultivation of mud crab.

[0005] The embodiment discloses a method for promoting spawning in mud crabs. The method comprises domesticating the crabs using water with the same salinity as that of the crab breeding pond; stimulating the domesticated crabs using low-temperature, low-salinity water; and inducing the stimulated crabs using high-temperature, high-salinity water.

[0006] The present application promotes efficient spawning of mud crabs by sequentially domesticating, stimulating and inducing the breeding of mud crabs, and continuously controlling sudden changes in water temperature and salinity. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A schematic flow chart of a method for promoting spawning in mud crabs provided in an embodiment.

[0008] Figure 2 This is a schematic diagram of the specific process of step S100 provided in the embodiment.

[0009] Figure 3 This is a schematic diagram of the specific process of step S200 provided in the embodiment.

[0010] Figure 4 This is a schematic diagram of the specific flow of step S300 provided in the embodiment. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the following examples. It should be understood that the specific examples described herein are merely for the purpose of explaining this application and are not intended to limit this application. Reagents not described in detail in this application are all conventional reagents and can be obtained from commercial channels; methods not specifically described in detail are all conventional experimental methods and can be obtained from the prior art.

[0012] like Figure 1 As shown, the embodiment discloses a method for promoting the spawning of mud crabs. The method comprises:

[0013] S100, domesticating the crabs using water with the same salinity as that of the crab breeding pond;

[0014] S200, using low-temperature and low-salinity water to stimulate the cultivation of the domesticated crabs; and

[0015] S300, using high-temperature and high-salt water to induce aquaculture of the crabs that have undergone the stimulation aquaculture.

[0016] Among them, the water body with the same salinity as the water body in the crab breeding pond refers to seawater with a temperature of 25-28°C and sand filtration. The salinity of the water body is increased or decreased by brine or tap water to make it consistent with the salinity of the water body in the crab breeding pond.

[0017] Among them, the low-temperature and low-salinity water body is seawater or tap water with a salinity of 15‰, a temperature of 13-15°C, and has been sand filtered and disinfected.

[0018] Among them, the high-temperature and high-salt water body is seawater or tap water with a salinity of 25‰, a temperature of 25-28°C, and has been sand filtered and disinfected.

[0019] like Figure 2 As shown, some embodiments provide step S100 including:

[0020] S101, prepare a crab breeding pond with a water inlet and a water outlet, lay a cleaned and disinfected sand bed occupying 1 / 3 of the pond bottom area on one side of the water inlet, the sand thickness is about 12 cm, lay heating pipes and air pipes, and cover the pond with a shade net;

[0021] S102, preparing a first water reservoir containing water having a salinity consistent with that of the crab breeding pond;

[0022] S103, adding water from the first water reservoir to the crab breeding pond through the water inlet, controlling the water depth to 40-45 cm, placing the screened, disinfected, and cultured mud crabs in the crab breeding pond for three days of adaptive domestication, feeding the crabs with cleaned razor clams at 5 p.m. every day during the domestication period, with the amount of razor clams fed being 20% ​​of the crab's weight on the first day, and then increasing or decreasing the amount based on the crab's feeding habits, removing uneaten bait and residues at around 7 a.m., and changing the water for the crabs with the water cultured in the first water reservoir on the mornings of the second and third days of domestication, with a water change of 70% every day.

[0023] like Figure 3 As shown, some embodiments provide step S200 including:

[0024] S201, prepare a second water reservoir containing low-temperature and low-salinity water;

[0025] S202, after the acclimation is completed, drain the water used for acclimation in the crab breeding pond, stop draining when the remaining water depth is 5 cm, add water from the second reservoir to the crab breeding pond until the water depth is 50 cm, and perform stimulation acclimation acclimation on the crabs for 3 days;

[0026] S203. Feed the crabs with cleaned razor clams at 5:00 p.m. every day during the stimulation culture period. On the first day, the amount of razor clams fed is 20% of the crabs' weight, and the amount is increased or decreased according to the crabs' eating habits. Uneaten bait and residues are removed at around 7:00 a.m., and the water for the brood crabs is replaced with the water from the second reservoir on the morning of the second and third days, with a water replacement rate of 70% per day.

[0027] like Figure 4 As shown, some embodiments provide step S300 including:

[0028] S301, preparing a second water reservoir containing high-temperature and high-salinity water;

[0029] S302, after the stimulated aquaculture is completed, the low-temperature, low-salinity water in the crab breeding pond is drained, and the drainage is stopped when the remaining water depth is 5 cm, and water in the third reservoir is added to the crab breeding pond to a water depth of 50 cm to induce aquaculture of the crabs;

[0030] S303. During the induction culture period, cleaned razor clams were fed to the crabs at 5 p.m. every day. On the first day, the amount of razor clams fed was 20% of the crab's weight, and then the amount was increased or decreased according to the crab's feeding situation. Uneaten bait and residues were cleaned at around 7 a.m., and water was changed in a 24-hour running water manner during the induction culture period.

[0031] The following will illustrate the implementation of the present application with reference to more specific examples, but does not constitute a limitation on all implementations of the present application.

[0032] The embodiment discloses a method for promoting the spawning of mud crabs. The method comprises:

[0033] (1) Prepare crab breeding pond

[0034] A 20-40 cubic meter cement pond is suitable for breeding crabs. A sand bed that occupies 1 / 3 of the pond bottom area is laid on the side near the water inlet. The thickness of the sand is about 12 cm. Heating pipes and air pipes are laid, and the pond is covered with a shade net to create a dark and quiet breeding environment for the breeding crabs.

[0035] (2) Preparation of water bodies for cultivation

[0036] Prepare three cement pools as water reservoirs next to the crab breeding pond.

[0037] A pool is filled with sand-filtered seawater, and the salinity of the water body is increased or decreased with brine or tap water to make it consistent with the salinity of the water body in the crab breeding pond, which serves as the first water reservoir for water exchange during the crab breeding period;

[0038] A cement pool is filled with sand-filtered seawater and its salinity is adjusted to 15‰ with tap water, which serves as the second water reservoir for water exchange during the low-salt and low-temperature breeding of crabs.

[0039] A cement pool is filled with sand-filtered seawater and its salinity is adjusted to 25‰ with brine, which serves as the third water reservoir for water exchange during the high-salt and high-temperature breeding period of brood crabs and the cultivation of brood crabs.

[0040] After adjusting the salinity of the three reservoirs, they were disinfected with sodium hypochlorite. The water was preheated the day before use: Reservoir X1 to 25-28°C, Reservoir X2 to 13-15°C, and Reservoir X3 to 25-28°C. To prevent the growth of pathogenic microorganisms in each reservoir, the water was oxygenated and reduced one hour before use.

[0041] (3) Domestication

[0042] Select large, healthy-limbed, energetic blue crabs with well-developed ovaries. Tie them up and transport them to the nursery. Dissolve 10 ml of formaldehyde in 50 liters of decontaminated water from the first reservoir. Mix thoroughly and pour into a red basin. Place each crab individually into the basin and soak for 30 minutes for disinfection.

[0043] The domesticated water in the first water reservoir is pumped into the crab breeding pond, and the water depth is controlled at 40-45 cm.

[0044] After disinfecting and culturing, the brood crabs are untied and placed in the brood crab cultivation pond for three days of acclimatization. During this period, they are fed clean razor clams at 5:00 PM daily. On the first day, the razor clam intake is 20% of the crab's weight, and the amount is increased or decreased based on the crab's feeding habits. Uneaten bait and debris are removed around 7:00 AM. On the mornings of the second and third days of acclimatization, the brood crabs' water is exchanged with fresh water from the primary reservoir, with a 70% water change daily.

[0045] (4) Stimulate breeding

[0046] After the domestication is completed, the water used for domestication in the crab breeding pond is drained.

[0047] To avoid damaging brooding crabs that have already laid eggs during the acclimation period, drainage is stopped when the remaining water depth reaches 5 cm. Pre-cultured low-salinity, low-temperature water from the second reservoir is promptly added to the brooding crab culture tank to a depth of 50 cm. This stimulates the brooding crabs for three days. Cleaned razor clams are fed daily at 5:00 PM during the stimulation period. On the first day, the razor clam intake is 20% of the crab's weight, and the amount is increased or decreased based on the crab's feeding habits. Uneaten bait and debris are removed around 7:00 AM. On the mornings of the second and third days, the crabs' water is replaced with pre-cultured water from the second reservoir, with a 70% water change daily.

[0048] (5) Induced breeding

[0049] After the stimulation breeding is completed, the low-temperature and low-salt water in the crab breeding pond is drained. When the remaining water depth is 5 cm, the drainage is stopped, and the high-temperature and high-salt water cultured in the third reservoir is added in time to a water depth of 50 cm in the crab breeding pond to induce breeding of the crabs.

[0050] During the induction breeding period, cleaned razor clams were fed at 5 pm every day. On the first day, the amount of razor clams fed was 20% of the crab's weight, and then increased or decreased according to the crab's eating habits. Uneaten bait and residues were cleaned at around 7 am. On the morning of the second and third days, the water for the breeding crabs was changed with the water from the third reservoir, and 70% of the water was changed every day.

[0051] However, since a large number of brooding crabs appear on the second day of induced ovulation, water changes are performed 24 hours a day to prevent the frequent water changes from disrupting ovulation and stimulating the brooding crabs. Statistics show that after the completion of the appropriate stimulation culture, the number of brooding crabs accounts for 1.7% of the total brooded crabs. This percentage rises to 53.3% on the second day after induced ovulation, and 78.3% on the second day after induced ovulation. By the end of the entire induced culture process, the brooding rate of brooded crabs reaches 81.7%. See the table below for specific brooding rates.

[0052] Table 1 Statistics of crab cultivation provided in the embodiment

[0053]

[0054] On the third day, after the number of brooding crabs stabilizes or only a minimal increase in brooding crabs, examine the embryonic development of the brooding crabs. Based on the number of hatching buckets and production needs, remove any brooding crabs whose eggs have turned gray or black. After soaking in 2 pmol formaldehyde, transfer them to hatching buckets for incubation. Move any brooding crabs that are yellow, orange, or brown to the brooding crab incubation pond for temporary rearing. Any roe crabs that fail to ovulate after induction should be re-induced or reared using other methods.

[0055] In addition, as a control, the conventional method was used to culture roe crab eggs, and the specific process was as follows:

[0056] Select large, healthy, energetic blue crabs with well-developed ovaries. After tying and tying, transport them to the nursery for brooding. The brooding process requires maintaining stable water quality and temperature in the brooding pond. Salinity should be controlled between 20‰ and 25‰, and the water temperature between 24°C and 26°C. Maintain a low flow rate, with daily water changes of 1 / 3 to 1 / 2 of the pond's volume. Ensure adequate dissolved oxygen levels, with the dissolved oxygen content above 5 mg / L. During the brooding period, female crabs' food intake increases, so ensure an adequate supply of food. Food should primarily consist of high-quality shellfish and shrimp, with some algae, such as seaweed, also added in moderation. Daily feed intake can be increased to 8% to 12% of the brood crabs' body weight and adjusted accordingly based on their feeding habits. Regularly monitor the brood crabs' activity, feeding, and brooding, and remove any remaining bait and feces to maintain clean water quality. When the eggs of the crabs are found to be loose or about to hatch, they should be moved into the hatching pond for hatching.

[0057] Table 2 Statistics of crab culture provided by the control group

[0058]

[0059] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A method for promoting spawning of mud crabs, comprising: The brood crabs are domesticated using water with the same salinity as that of the brood crab breeding pond; Using low-temperature, low-salinity water to stimulate aquaculture of the domesticated crabs, wherein the low-temperature, low-salinity water is seawater or tap water with a salinity of 15‰, a temperature of 13-15°C, and sand-filtered and sterilized; and The crabs that have undergone the stimulation culture are induced to culture in high-temperature and high-salt water. The high-temperature and high-salt water is seawater or tap water with a salinity of 25‰ and a temperature of 25-28°C that has been sand filtered and disinfected.

2. The method according to claim 1, wherein the water body having the same salinity as that of the crab breeding pond water body refers to seawater having a temperature of 25-28°C and having been sand-filtered, and the salinity of the water body is increased or decreased by brine or tap water to make it consistent with the salinity of the crab breeding pond water body.

3. The method according to claim 1, wherein the step of domesticating the crabs using water having the same salinity as that of the crab breeding pond comprises: Prepare a crab breeding pond with a water inlet and a water outlet, lay a cleaned and disinfected sand bed occupying 1 / 3 of the pond bottom area on one side of the water inlet, with a sand thickness of 12 cm, lay heating pipes and air pipes, and cover the pond with a shade net; Prepare a first reservoir containing water of the same salinity as that of the crab breeding pond; The water in the first water reservoir is added to the crab breeding pond through the water inlet, and the water depth is controlled at 40-45 cm. The screened, disinfected and cultured mud crabs are placed in the crab breeding pond for three days of adaptive domestication. During the domestication period, cleaned razor clams are fed at 5 pm every day. The amount of razor clams fed on the first day is 20% of the crab's weight, and the amount is increased or decreased according to the crab's feeding situation. Uneaten bait and residues are cleaned at 7 am. On the morning of the second and third days of domestication, the water for the crabs is replaced with the water cultured in the first water reservoir, and 70% of the water is replaced every day.

4. The method according to claim 3, wherein the step of using low-temperature, low-salinity water to stimulate the domesticated crabs to culture comprises: After the domestication is completed, the water used for domestication in the crab breeding pond is drained, and the drainage is stopped when the remaining water depth is 5 cm. Water from the second reservoir is added to the crab breeding pond to a water depth of 50 cm, and the crabs are subjected to low temperature and low salt stimulation for 3 days; During the stimulation culture period, cleaned clams were fed to the crabs at 5 pm every day. On the first day, the amount of clams fed was 20% of the crab's weight, and then increased or decreased according to the crab's eating habits. Uneaten bait and residues were cleaned at 7 am. On the morning of the second and third days, the water for the crabs was changed with the water from the second reservoir, and 70% of the water was changed every day.

5. The method according to claim 3, wherein the step of inducing aquaculture of the crabs after the stimulation aquaculture using high temperature and high salinity water comprises: After the stimulation culture is completed, the low-temperature and low-salinity water in the crab breeding pond is drained, and the drainage is stopped when the remaining water depth is 5 cm. Water in the third reservoir is added to the crab breeding pond to a water depth of 50 cm to induce the breeding of crabs; During the induction culture period, cleaned clams were fed at 5 pm every day. The amount of clams fed on the first day was 20% of the crab's weight, and then increased or decreased according to the crab's eating habits. Uneaten bait and residues were cleaned at 7 am. During the induction culture period, water was changed in a 24-hour running water manner.

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