Method for indoor fast breeding of estuarine crab

Abstract

The present application belongs to the technical field of aquaculture, and particularly relates to an indoor rapid breeding method of soft-shell blue crab. The method mainly comprises several key links such as selection of female crabs, water quality, bait and salinity and temperature management, and the proportion of soft-shell blue crab can be increased by 66-75%, which solves the problems of low natural conversion rate, unstable quality and long breeding cycle of soft-shell blue crab in traditional green crab breeding. The indoor breeding method of soft-shell blue crab is simple, has short breeding cycle, high operability, simple method, high efficiency, easy popularization and high practicability.

Description

Technical Field

[0001] This invention belongs to the technical field of aquaculture, specifically relating to a method for the rapid indoor rearing of oily and yellow crabs. Background Technology

[0002] The mud crab (Scylla paramamosain) is an important farmed crab species in the southeastern coastal areas of my country. The "yellow butter crab" is a special growth stage of female mud crabs, rich in nutrients such as carotenoids, lecithin, and polyunsaturated fatty acids. Its body fluid is golden yellow, and its swimming leg joint membrane is orange-yellow. It is commonly found in the brackish water areas of Hong Kong's Deep Bay and the Pearl River Delta. The probability of a yellow butter crab occurring in a natural population is extremely low; only one in a thousand female crabs might produce one. Furthermore, its survival time after capture is short, and its price is over 1200 yuan per kilogram, more than 10 times that of ordinary mud crabs, earning it the reputation of "King of Crabs." The yellow butter crab has tender meat and rich, sweet roe with a unique texture, resembling a flowing salted egg yolk. It is a top-grade ingredient abundant in the Guangdong-Hong Kong-Macao Greater Bay Area. Due to its unique taste, flavor, and excellent nutritional quality, the yellow butter crab is highly favored by consumers and has a broad market prospect.

[0003] Currently, yellow butter crabs on the market are mainly divided into three quality grades: full-oil, head-and-hand, and roe-oil. Full-oil yellow butter crabs have virtually undeveloped gonads, and a golden-yellow "oily substance" has permeated all parts of their body; yellow oil is visible inside the shell and at the joints of the legs. Head-and-hand yellow butter crabs, commonly known as "a little red," have red gonads, and yellow oil is visible inside the shell and at the joints of the legs; the abdominal muscles are permeated with a golden-yellow "oily substance." Roe-oil yellow butter crabs have full gonads, and yellow oil is visible inside the shell and at the joints of the legs; the abdominal muscles are permeated with a golden-yellow "oily substance." Currently, the cultivation methods and formation causes of yellow butter crabs are still unclear both domestically and internationally. Farmers' harvests of yellow butter crabs are currently highly unpredictable, making market supply unsustainable and leading to persistently high prices. This seriously affects the healthy and sustainable development of this new farmed product in my country. Summary of the Invention

[0004] To address the above problems, the present invention aims to provide a method for the rapid indoor cultivation of roe and oil crabs.

[0005] The technical content of this invention is as follows:

[0006] This invention provides a method for indoor cultivation of roe and oil crabs, comprising the following steps:

[0007] 1) Screening of female crabs: selecting adult female crabs that, after reproductive molting, have an oval abdomen, a small area of light transmission at the serrated edge of the carapace when irradiated with light, are full of paste, have a gonad index > 6, have slightly transparent pale yellow at appendage joints, have a swimming leg joint membrane color in the range of 8 < b* < 12 detected by a color difference meter, and weigh 250-300 g;

[0008] 2) Culture site: an indoor recirculating aquaculture system is adopted, culture glass tanks are rectangular, and hiding shelters are arranged in the tanks;

[0009] the dimension of a single tank is length×width×height = 1.2×0.6×0.6 m, and the culture density is 3 crabs per tank;

[0010] 3) Water quality management: natural seawater is diluted with aerated tap water to control the salinity at 12-15‰, the water temperature is controlled at 25°C, dissolved oxygen ≥ 6 mg / L, ammonia nitrogen ≤ 0.05 mg / L, the water depth is 0.4 m, and one quarter of the water in each tank is changed every week;

[0011] 4) Bait feeding management: fresh Potamocorbula laevis is used for feeding throughout the culture process;

[0012] 5) Detection of fattened creamy crabs: female crabs are harvested after 45 days of culture, the color of the swimming leg joint membrane of the female crabs is detected by a color difference meter, and those with a yellow-blue value b* > 12 are yellow creamy crabs, so that high-proportion fattened creamy crabs are obtained.

[0013] The beneficial effects of the present invention are as follows:

[0014] The indoor cultivation method for fattened creamy crabs of the present invention mainly includes several key links: female crab screening, culture water quality, bait, and salinity and temperature management. The proportion of fattened creamy crabs can be increased by 66-75%, which solves the problems of low natural conversion rate, unstable quality, long culture cycle and other problems in traditional mud crab culture. The indoor cultivation technical method for fattened creamy crabs of the present invention is simple, has short culture cycle, strong operability, simple method, high efficiency, easy popularization, and strong practicability. Description of Drawings

[0015] Figure 1 is a schematic diagram showing marking of appearance parts of the screened female crab;

[0016] Figure 2 is a result diagram showing the screened female crabs and the swimming leg joint membranes and color values of the fattened creamy crabs after 45 days of culture. Detailed Description

[0017] Hereinafter, the present invention will be described in further detail with reference to specific implementation examples and the accompanying drawings. It should be understood that these examples are only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the present invention, modifications to various equivalent forms of the present invention made by those skilled in the art all fall within the scope defined by the claims appended to the present application.

[0018] Unless otherwise specified, all raw materials and reagents used in the present invention are conventional commercially available raw materials and reagents.

[0019] Example 1

[0020] An indoor rapid cultivation method for creamy yellow crabs

[0021] Location: Indoor recirculating aquaculture system of Guangzhou Nansha Fisheries Research Institute of South China Agricultural University

[0022] Time: March 2024 to May 2024.

[0023] 300 female wild mud crabs caught from the natural sea area of Shuidong Bay, Dianbai District, Maoming City, Guangdong Province were subjected to the following steps for screening and cultivation of creamy yellow crabs.

[0024] 1) Selection of female crabs: After the female crabs undergo reproductive molting, 60 adult female crabs are selected, which meet the following characteristics: oval abdominal umbilicus; when the serrated edge of the carapace is irradiated with transmitted light, only a small area at the edge is translucent; appendage joints are transparent pale yellow; the color of the swimming pod joint membrane of the female crab detected by a colorimeter satisfies 8 < b* < 12; and the weight is 252-304g;

[0025] 2) Cultivation site: an indoor recirculating aquaculture system, where the cultivation glass tanks are rectangular in shape, the length × width × height of a single tank is 1.2×0.6×0.6m, there are 20 tanks in total, the cultivation density is 3 crabs per tank, and hiding shelters are provided in the tanks;

[0026] 3) Water quality management: natural seawater is diluted with aerated tap water to control the salinity at 12-15‰, the water temperature is controlled at 25°C, the dissolved oxygen is greater than 6mg / L, the ammonia nitrogen is less than 0.05mg / L, the water depth is 0.4m, and one quarter of the water in each tank is changed every week.

[0027] 4) Bait feeding management: fresh *Potamocorbula laevis* is used for feeding throughout the cultivation period. Feeding is carried out once at 7:00 a.m. and once at 6:00 p.m. respectively, with satiation feeding adopted. Residual bait is fished out in time two hours after feeding, and the total feeding period is 45 days.

[0028] 5) After 45 days of cultivation, the color of the swimming pod joint membrane of female crabs is detected by a colorimeter, and 45 creamy yellow crabs with a weight of 255-312g are obtained (crabs with yellow-blue value b* > 12 are classified as yellow creamy crabs), accounting for 75% of the total cultured female crabs.

[0029] The above examples illustrate that the use of the present invention can significantly increase the rearing proportion of creamy yellow mud crabs.

[0030] Example 2

[0031] An indoor rearing method for creamy yellow mud crabs

[0032] Location: Indoor recirculating aquaculture system of Guangzhou Nansha South China Agricultural University Fisheries Research Institute

[0033] Time: May 2024 to July 2024.

[0034] 400 female mud crabs were caught from the natural sea area in Nansha District, Guangzhou, Guangdong Province, and the following steps were taken for screening and rearing of creamy yellow mud crabs.

[0035] 1. Selection of female crabs: After the reproductive molting of female crabs, 60 adult female crabs were selected, which have oval abdominal nave, only a small area at the edge of the serrated edge of the thorax transmits light when irradiated, the appendage joints are transparent light yellow, the color of the swimming leg joint membrane of female crabs detected by a colorimeter satisfies 8 < b* < 12, and the body weight ranges from 260g to 290g.

[0036] 2. Culture site: An indoor recirculating aquaculture system is adopted, the culture glass tanks are rectangular in shape, the length*width*height of a single tank is 1.2*0.6*0.6 m, there are 20 tanks in total, the culture density is 3 crabs per tank, and hiding shelters are arranged in the tanks.

[0037] 3. Water quality management: Natural seawater is diluted with aerated tap water to control the salinity at 12-15‰, the water temperature is controlled at 25°C, the dissolved oxygen is more than 6mg / L, the ammonia nitrogen is less than 0.05mg / L, the water depth is 0.4m, and the water exchange amount is one quarter of the water volume per tank every week.

[0038] 4. Bait feeding management: Fresh Potamocorbula laevis is used for feeding throughout the whole culture period, feeding is carried out once at 7:00 AM and 6:00 PM respectively, with satiation feeding adopted, residual baits are fished out in time two hours after feeding, and the total feeding period is 45 days.

[0039] 5. After 45 days of culture, the color of the swimming leg joint membrane of female crabs is detected by a colorimeter, 42 creamy yellow mud crabs with a weight of 265-310g are obtained (crabs with yellow-blue value b*>12 are yellow cream crabs), accounting for 70% of the total cultured female crabs.

[0040] The above example illustrates that the use of the present invention can significantly increase the rearing proportion of creamy yellow mud crabs.

[0041] Example 3

[0042] An indoor rearing method for creamy yellow mud crabs

[0043] Location: Indoor recirculating aquaculture system of Guangzhou Nansha Huanong Fisheries Research Institute

[0044] Time: July 2024 - September 2024

[0045] 380 female mud crabs were caught by sea fishing from the natural sea area of Doumen District, Zhuhai City, Guangdong Province. The following steps are adopted for screening and cultivating fat-yellow creamy crabs.

[0046] 1. Selection of female crabs: 60 adult female crabs were selected after the reproductive molting of female crabs, which meet the following indicators: the abdomen is elliptical, when irradiated by transmitted light, only a small area of the serrated edge of the carapace is translucent, the appendage joints are transparent light yellow, the color of the swimming leg joint membrane of the female crab detected by a colorimeter is 8 < b* < 12, and the weight is 255-288g.

[0047] 2. Breeding site: an indoor recirculating aquaculture system, the breeding glass tanks are rectangular in shape, the length×width×height of a single tank is 1.2×0.6×0.6m, there are 20 tanks in total, the breeding density is 3 crabs per tank, and hiding shelters are arranged in the tanks.

[0048] 3. Water quality management: natural seawater is diluted with aerated tap water to control the salinity at 12-15‰, the water temperature is controlled at 25°C, the dissolved oxygen is more than 6mg / L, the ammonia nitrogen is less than 0.05mg / L, the water depth is 0.4m, and the water exchange amount is one quarter of the water volume per tank every week.

[0049] 4. Bait feeding management: fresh Potamocorbula laevis is used for feeding throughout the whole breeding process, feeding is carried out once at 7:00 in the morning and 18:00 in the evening respectively, with satiety feeding amount, the residual bait is fished out in time two hours after feeding, and the total feeding period is 45 days.

[0050] 5. After 45 days of breeding, the color of the swimming leg joint membrane of female crabs is detected by a colorimeter, and 40 fat-yellow creamy crabs with a weight of 263-305g are obtained (when the yellow-blue value b*>12, it is determined as yellow creamy crab), and the proportion of fat-yellow creamy crabs accounts for 66.67% of the bred female crabs.

[0051] The above embodiment shows that the use of the present invention can significantly increase the cultivation proportion of fat-yellow creamy crabs.

[0052] As Figure 1 shows the state of the screened female crab, Figure 2 is the joint membrane of the fat-yellow creamy crab after 45 days of breeding. The color value of the female crab's swimming leg joint membrane detected by the colorimeter is 8 < b* < 12, which indicates that the fat-yellow creamy crab is successfully cultivated, and the cultivation proportion of fat-yellow creamy crabs is improved.

[0053] Comparative Example 1

[0054] Location: Indoor recirculating aquaculture system of Guangzhou Nansha Huanong Fisheries Research Institute

[0055] Time period: March 2024 - May 2024.

[0056] Two hundred female mud crabs were caught in the natural sea area of ​​Shuidong Bay, Dianbai District, Maoming City, Guangdong Province. The following steps were taken to select and cultivate the female crabs.

[0057] 1) Selection of female crabs: Select 60 adult female crabs that have undergone reproductive molting, with an oval abdominal navel, serrated edges of the carapace that are translucent when exposed to light, transparent grayish-white appendage joints, and a colorimeter color of b*<8 for the joint membrane of the swimming legs, and weighing 246-295g.

[0058] 2) Breeding site: Indoor recirculating aquaculture system, the breeding glass tanks are rectangular in shape, each tank is 1.2m long*0.6m wide*0.6m high, there are 20 tanks in total, the breeding density is 3 animals / tank, and there are hiding places in the tanks;

[0059] 3) Water quality management: Dilute natural seawater with aerated tap water to control salinity at 12-15‰, water temperature at 25℃, dissolved oxygen greater than 6mg / L, ammonia nitrogen less than 0.05mg / L, water depth 0.4m, and change one-quarter of the water volume per tank every week.

[0060] 4) Feed management: Fresh white clams (Potamocorbula laevis) are fed throughout the breeding process. Feeding times are 7:00 am and 6:00 pm, and the amount of feed is given until the clams are full. Any leftover feed is removed two hours after feeding. The feeding is carried out for a total of 45 days.

[0061] 5) After 45 days of culture, the color of the joint membrane of the swimming legs of the female crabs was detected by colorimeter. A total of 0 crabs with roe and yellow oil were obtained, with a yellow-blue value b*<8. The proportion of crabs with roe and yellow oil accounted for 0% of the cultured female crabs.

[0062] The above comparisons demonstrate that the selection of female crabs can significantly affect the growth rate of roe and butter crabs.

[0063] Comparative Example 2

[0064] Location: Indoor recirculating aquaculture system, Guangzhou Nansha Huanong Fisheries Research Institute

[0065] Time period: May 2024 - July 2024.

[0066] 280 female mud crabs were caught in the natural sea area of ​​Nansha District, Guangzhou City, Guangdong Province. The following steps were taken to select and cultivate the female crabs.

[0067] 1) Selection of female crabs: After the reproductive molting of female crabs, select 60 adult female crabs with oval abdominal navels, small partial light transmission at the edges when the serrated edges of the carapace are irradiated by light, transparent light yellow at the appendage joints, 8 < b* < 12 for the color of the swimming leg joint membrane of female crabs detected by a color difference meter, and a weight of 248-294g.

[0068] 2) Culture site: an indoor recirculating aquaculture system, where culture glass tanks are rectangular in shape, each tank has a length*width*height of 1.2*0.6*0.6m, there are 20 tanks in total, the culture density is 3 crabs per tank, and hiding shelters are arranged in the tanks.

[0069] 3) Water quality management: dilute natural seawater with aerated tap water to control the salinity at 12-15‰, control the water temperature at 25°C, keep dissolved oxygen greater than 6mg / L, ammonia nitrogen less than 0.05mg / L, and water depth at 0.4m, and change one quarter of the water volume per tank every week.

[0070] 4) Bait feeding management: feed with fresh river snails (Cipangopaludina chinensis), feed once at 7:00 in the morning and 18:00 in the evening respectively, adopt satiation feeding, remove residual bait in time two hours after feeding, and the total feeding period is 45 days.

[0071] 5) After 45 days of culture, the color of the swimming leg joint membrane of female crabs is detected by a color difference meter, 0 creamy-yellow paste crabs are obtained in total, with the blue-yellow value b* < 8, and the proportion of creamy-yellow paste crabs in the cultured female crabs is 0%.

[0072] The above comparative example shows that bait feeding management can significantly affect the culture proportion of creamy-yellow paste crabs.

Claims

1. A method for the rapid indoor rearing of roe and butter crabs, characterized in that, Includes the following steps: 1) Female crab selection: Select female crabs after reproductive molting. The abdominal navel should be oval. When illuminated, a small area of ​​the serrated edge of the cephalothorax should be translucent, indicating abundant roe. The gonad index should be >6. The appendage joints should be slightly transparent and light yellow. Colorimeter analysis should show a color of 8 < for the joint membranes of the female crab's swimming legs. b* <12, adult female crabs weighing 250-300g; 2) Breeding site: An indoor recirculating aquaculture system is used. The breeding glass tanks are rectangular in shape and have hiding places inside. 3) Water quality management: Dilute natural seawater with aerated tap water to control salinity at 12-15‰, water temperature at 25℃, dissolved oxygen ≥6 mg / L, ammonia nitrogen ≤0.05 mg / L, water depth 0.4 m, and change one-quarter of the water volume per tank every week; 4) Feeding management: Feed fresh white clams continuously for 45 days; 5) Detection of Yellow Roe and Oil Crab: Female crabs were harvested after 45 days of culture. The color of the joint membrane of the swimming legs of the female crabs was detected by a colorimeter, and the yellow-blue value was measured. b* >12 indicates a high percentage of roe and butter crab.

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