Method for promoting spawning of scylla paramamosain cream crabs

Abstract

The invention belongs to the technical field of scylla paramamosain, and particularly relates to a method for promoting spawning of scylla paramamosain cream crabs. The method comprises the following steps: domesticating parent crabs by adopting a water body with the same salinity as that of a parent crab culture pond water body; adopting a low-temperature and low-salt water body to stimulate and breed the domesticated breeding crabs; and adopting a high-temperature and high-salt water body to carry out induced breeding on the breeding crabs subjected to stimulation breeding. According to the method, efficient egg carrying of scylla paramamosain is promoted through the technical measures that domestication, stimulation breeding and induction breeding are sequentially conducted on the parent scylla paramamosain, and then sudden changes of water temperature and salinity are continuously controlled.

Description

Technical Field

[0001] The present application belongs to the technical field of Scylla pseudoburrowingii, and specifically relates to a method for promoting Scylla pseudoburrowingii roe to incubate eggs. Background Art

[0002] Scylla paramamosain is a marine crab of the genus Scylla in the family Portunidae. Scylla paramamosain is rich in protein and trace elements, such as calcium, phosphorus, iron, zinc, etc., which have a good tonic effect on the body. Traditional Chinese medicine believes that it has the effects of nourishing the kidney, eliminating accumulation, strengthening the spleen, nourishing the heart, and calming the nerves. The artificial propagation of Scylla paramamosain seedlings involves fattening and spawning of seed crabs, larval cultivation, and young crab cultivation. Among them, the time to obtain the spawning crabs and the number and quality of the spawning crabs directly determine the time and yield of artificial seedlings on the market, which in turn affects the subsequent benefits of blue crab farming.

[0003] At present, the main method of obtaining brooding crabs during the seedling raising process is to let crabs lay eggs naturally in the breeding pond. However, since their spawning behavior is affected by physiology and environment, it is difficult to obtain high-quality brooding crabs in a timely and appropriate amount during production. In previous studies, researchers referred to the methods of inducing spawning in fish and other crustacean species, and induced them to lay eggs by cutting off the eye stalks of crabs and injecting oxytocin into crabs, and achieved certain results. However, this operation has the disadvantages of large workload, high technical content, and easy infection of pathogenic microorganisms at the mechanically damaged parts of the parents after the operation, making these technologies difficult to be widely used in production. The researchers also referred to the methods of shellfish seedling raising, and carried out dry exposure culture on the temporarily fattened crabs to stimulate their spawning, but the dry exposure would cause damage to the brooding crabs already mixed in the breeding pond of the crabs. At the same time, some crabs would ovulate during the dry exposure, resulting in a waste of crabs. Summary of the invention

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

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

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

[0007] Figure 1A schematic flow chart of a method for promoting egg-carrying in Scylla pseudoburrowing crabs provided in an embodiment.

[0008] Figure 2 This is a schematic diagram of a specific flow chart of step S100 provided in an embodiment.

[0009] Figure 3 This is a schematic diagram of a specific flow chart of step S200 provided in an embodiment.

[0010] Figure 4 The specific flow chart of step S300 provided in the embodiment. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application is further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. The reagents not described separately in detail in the present application are all conventional reagents and can be obtained from commercial channels; the methods not 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 the mud crab. The method comprises:

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

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

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

[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-salt 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, preparing a crab breeding pond with a water inlet and a water outlet, laying 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, laying heating pipes and air pipes, and covering the pond with a sunshade net;

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

[0022] S103, adding the water in the first water reservoir into the crab breeding pond through the water inlet, and controlling the water depth to be 40-45 cm, placing the selected and disinfected mud crabs in the crab breeding pond for 3 days of adaptive domestication, feeding the crabs with cleaned clams at 5 pm every day during the domestication period, feeding the crabs with clams at a rate of 20% of the crab weight on the first day, and then increasing or decreasing the amount of clams according to the crabs' eating conditions, cleaning the uneaten baits and residues at around 7 am, and changing the water for the crabs with the water cultured in the first water reservoir on the second and third days of domestication, and changing 70% of the water 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 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, and the water in the second water reservoir is added to the crab breeding pond until the water depth is 50 cm, and the crabs are stimulated to be cultured for 3 days;

[0026] S203. Feed the crabs with cleaned clams at 5:00 p.m. every day during the stimulation culture period. On the first day, the amount of clams fed is 20% of the crab's weight. Thereafter, the amount is increased or decreased according to the crab's eating habits. Uneaten baits and residues are cleaned at around 7:00 a.m., and the water for the crabs is replaced with the water cultured in the second reservoir on the morning of the second and third days, with 70% of the water replaced every 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 salt water;

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

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

[0031] The following will describe the implementation methods of the present application in conjunction with more specific examples, but do not constitute limitations on all implementation methods of the present application.

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

[0033] (1) Prepare a 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 close to 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 is used as the first water reservoir for water replacement 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 breeding crabs and the cultivation of egg-bearing crabs.

[0040] After the salinity of the three reservoirs was adjusted, they were disinfected with sodium hypochlorite disinfectant water for breeding. The water was preheated one day before use, with the water in the X1 reservoir heated to 25-28°C, the water in the X2 reservoir heated to 13-15°C, and the water in the X3 reservoir heated to 25-28°C. In order to avoid the growth of pathogenic microorganisms in each reservoir, the water was oxygenated and reduced one hour before use.

[0041] (3) Domestication

[0042] Select large crabs with healthy limbs, vigorous vitality and plump ovaries, tie them up and transport them to the nursery base. Dissolve 10 ml of formaldehyde in 50 liters of the first reservoir water after disinfection and reduction, mix well and pour into the red basin. Put the crabs one by one into the basin and soak them for disinfection for 30 minutes.

[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 the disinfected and cultured crabs are untied, they are placed in the crab breeding pond for three days of adaptive domestication. During the domestication period, cleaned clams are fed at 5 pm every day. The amount of clams fed on the first day is 20% of the crab's weight, and then increased or decreased according to the crab's eating situation. Uneaten bait and residues are cleaned at around 7 am. On the second and third day of domestication, the water for the crabs is changed with the water cultivated in the first reservoir, and 70% of the water is changed every day.

[0045] (4) Stimulate breeding

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

[0047] In order to avoid damage to the crabs that have already laid eggs during the domestication period, the drainage is stopped when the remaining water depth is 5 cm, and the low-salt and low-temperature water cultivated in the second reservoir is added in time to the water depth of 50 cm in the crab breeding pond, and the crabs are stimulated by low temperature and low salt for 3 days. During the stimulation breeding period, cleaned razor clams are fed at 5 pm every day. The feeding amount of razor clams on the first day is 20% of the crab weight, and then it is increased or decreased according to the crab's eating situation. At about 7 o'clock in the morning, the uneaten bait and residues are cleaned, and the water for the crabs is changed with the water cultivated in the second reservoir in the morning of the second and third days, and the water is changed by 70% every day.

[0048] (5) Induced culture

[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 crabs.

[0050] During the induction breeding period, cleaned clams were fed at 5 pm every day. On the first day, the amount of clams fed was 20% of the crab's weight. Thereafter, the amount was increased or decreased according to the crab's eating habits. Uneaten bait and residues were cleaned at around 7 am. On the second and third mornings, 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 crabs with eggs appear on the second day of induced ovulation, in order to avoid the large-scale water changes interfering with the ovulation behavior of crabs and stimulating the crabs with eggs, the water change is carried out in a 24-hour flow mode during this stage. According to statistics, after the end of appropriate stimulation breeding, the number of crabs with eggs accounted for 1.7% of the total number of crabs with eggs, and the proportion rose to 53.3% on the second day after induced ovulation, and the proportion was 78.3% on the second day of induced ovulation. After the entire induced breeding process, the egg-carrying rate of crabs with eggs can reach 81.7%. See the table below for specific egg-carrying conditions.

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

[0053]

[0054] On the third day after the number of egg-bearing crabs stabilizes or only a very small number of egg-bearing crabs increase, check the embryonic development of the egg-bearing crabs. According to the number of hatching buckets and production needs, pick out some egg-bearing crabs whose egg masses have turned gray or black, and move them to the egg-bearing crab hatching bucket for cultivation after soaking in 2pmol formaldehyde. Some egg-bearing crabs with yellow, orange or brown colors are moved to the egg-bearing crab cultivation pool for temporary cultivation. Repeat the induction or other methods of cultivation for the crabs that have not ovulated after induction.

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

[0056] Select blue crabs with large individuals, healthy limbs, vigorous vitality, and well-developed ovaries, tie them up and transport them to the nursery base for egg-carrying cultivation. The egg-carrying cultivation process includes: the water quality and water temperature of the cultivation pond should be kept stable, the salinity can be controlled at 20‰-25‰, and the water temperature is 24℃-26℃. To maintain micro-flowing water, the daily water change volume is 1 / 3-1 / 2 of the volume of the cultivation pond water, and sufficient dissolved oxygen should be ensured at the same time, and the dissolved oxygen content should be maintained above 5 mg / L. During the egg-carrying period, the female crab's food intake will increase, and sufficient supply of bait should be guaranteed. The types of bait are mainly high-quality shellfish and shrimps, and some algae, such as laver, can also be fed in appropriate amounts. The daily feeding amount can be increased to 8%-12% of the body weight of the parent crab, and it should be adjusted in time according to the feeding situation of the parent crab. The activities, feeding and egg-carrying of the parent crab should be observed regularly every day, and the residual bait and feces should be removed in time to keep the water clean. When the eggs of egg-carrying crabs are found to be loose or about to hatch, they should be moved to 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 of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A method for promoting the egg-carrying of a mud crab comprising: The seed crabs are domesticated using water with the same salinity as that of the seed crab breeding pond; Using low-temperature and low-salinity water to stimulate the breeding of the domesticated crabs; and The crabs that have undergone the stimulation culture are induced to culture using high-temperature and high-salt water.

2. The method according to claim 1, wherein the water body having the same salinity as the water body in the crab breeding pond refers to seawater having a temperature of 25-28°C and having been filtered through sand, 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 water body in the crab breeding pond.

3. The method according to claim 1, wherein the low-temperature and low-salinity water body is seawater or tap water with a salinity of 15‰ and a temperature of 13-15°C, which has been sand filtered and disinfected.

4. The method according to claim 1, wherein the high-temperature and high-salt water body is seawater or tap water with a salinity of 25‰ and a temperature of 25-28°C, and has been sand filtered and disinfected.

5. The method according to claim 1, wherein the step of domesticating the seed crabs using water having the same salinity as that of the seed 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, the sand thickness is about 12 cm, lay heating pipes and air pipes, and cover the pond with a sunshade 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 selected, disinfected and cultured mud crabs are placed in the crab breeding pond for 3 days of adaptive domestication. Cleaned clams are fed at 5 pm every day during the domestication period. The amount of clams fed on the first day is 20% of the crab's weight, and then increased or decreased according to the crab's eating conditions. Uneaten baits and residues are cleaned at around 7 o'clock in the morning. On 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.

6. The method according to claim 1, wherein the step of using low-temperature and 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, and the water in the second water reservoir is added to the crab breeding pond until the water depth is 50 cm, and the crabs are subjected to low temperature and low salt stimulation for 3 days; During the stimulation breeding period, cleaned clams are fed at 5 pm every day. On the first day, the amount of clams fed is 20% of the crab's weight. Thereafter, the amount is increased or decreased according to the crab's eating habits. Uneaten bait and residues are cleaned up around 7 am. On the second and third mornings, the water for the breeding crabs is replaced with the water from the second reservoir, with 70% of the water replaced every day.

7. The method according to claim 1, wherein the step of inducing aquaculture of the seed crabs after the stimulation aquaculture using high temperature and high salt water comprises: After the stimulated 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, and the 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 induced 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. Thereafter, the amount was increased or decreased according to the crab's eating habits. Uneaten bait and residues were cleaned at around 7 am. During the induced culture period, water was changed in a 24-hour running water manner.

Images