Breeding and breeding method for cherax quadricarinatus

Abstract

The invention relates to the technical field of aquaculture, in particular to a cherax quadricarinatus breeding and breeding method which comprises the following steps: S1, selecting parent shrimps meeting the standards of weight, body length and the like for temporary rearing, controlling the environmental conditions of water temperature, salinity and the like, and feeding fresh baits; s2, after temporary rearing, transferring to an intensified rearing pond for separate rearing of male and female, adjusting environmental parameters, and feeding compound feed and fresh bait; s3, after gonad maturity, putting into a mating pond according to a ratio of 1: 1, arranging a hidden object, and transferring to a spawning pond after finding that female shrimps carry eggs; s4, taking eggs for hatching after the female shrimps lay eggs, and controlling the environment of the hatching pond; s5, entering a zoeae breeding stage after the larvae are hatched, feeding by stages, and breeding by stages according to body length. Each pond is disinfected before being used, and diseases are prevented and controlled regularly in the whole process. According to the method, the quality of the parent shrimps is guaranteed, the mating and spawning efficiency is high, the hatching environment is excellent, larva growth is good, immunity can be enhanced, an efficient scheme is provided for large-scale breeding, cost is reduced, and economic benefits are improved.

Description

Technical Field

[0001] The invention relates to the technical field of aquaculture, in particular to a method for breeding and raising red claw crayfish. Background Art

[0002] As a freshwater crustacean aquaculture species with high economic value, red claw crayfish has become an important aquaculture target in southern my country with its delicious meat, fast growth rate and strong environmental adaptability. Large-scale and efficient breeding and seedling raising technology is the core link in promoting the development of the red claw crayfish industry, which directly affects the aquaculture output and economic benefits. However, the current red claw crayfish breeding and seedling raising technology still faces many bottlenecks. Traditional methods have problems such as asynchronous gonadal development of parent shrimps, low mating and spawning efficiency, low larval survival rate and frequent diseases, resulting in high seedling raising costs and uneven specifications, which are difficult to meet the needs of large-scale aquaculture. Therefore, optimizing the breeding and seedling raising process and improving the precise control of technical parameters in key links have become important issues that need to be urgently addressed in this field.

[0003] Although existing technologies (such as Chinese patents CN114158505B, a method for efficiently cultivating red claw crayfish, and CN114158509A, a method for rapidly growing red claw crayfish) have made some progress in the field of red claw crayfish cultivation, significant technical bottlenecks still exist in the key links of breeding and raising seedlings, as follows:

[0004] 1. Extensive broodstock cultivation and management techniques, low gonadal development efficiency

[0005] Chinese patent CN114158505B, a method for efficiently cultivating red claw crayfish, only mentions basic parameters such as water temperature and density for temporary broodstock rearing. Key screening criteria such as appendage integrity and gonad appearance are not specified. Furthermore, the patent lacks precise environmental control and nutritional matching for intensive rearing of males and females in separate pools. For example, CN114158505B does not address the use of probiotics during the intensive rearing period, making it difficult to effectively improve intestinal flora and water quality. This results in a prolonged gonadal development cycle and low synchronization rate for broodstock, impacting subsequent mating and spawning efficiency.

[0006] 2. Lack of environmental control for mating and egg laying, resulting in low egg hatching survival rate

[0007] While prior art Chinese patent CN114158505B mentions transferring brooding shrimp to culture tanks, it lacks a separate mating and spawning tank system. This lacks control over key parameters such as shelter density, light intensity, and dissolved oxygen, leading to low mating success rates and high egg contamination rates. Furthermore, prior art lacks technology for promptly removing dead and moldy eggs during incubation, nor does it include a micro-flow water circulation system. This results in significant fluctuations in water quality in the incubation tanks, and egg survival rates generally fall below 60%.

[0008] Existing technologies do not clearly define standardized disinfection procedures for temporary holding ponds, hatching ponds and other facilities, which can easily lead to cross-contamination; at the same time, there is a lack of precise control of pH and salinity during the incubation period and the frequency of cleaning leftover bait and feces during the larval cultivation period, resulting in a high risk of water quality deterioration, which seriously affects the success rate of seedling cultivation. Summary of the Invention

[0009] The object of the present invention is to provide a method for breeding and raising red claw crayfish to solve the problems raised in the above background technology.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A method for breeding and raising red claw crayfish, comprising the following steps:

[0012] S1. Selection and temporary rearing of broodstock: Select red claw crayfish with a strong physique, intact appendages, no injuries, strong vitality, and well-developed gonads as broodstock. Females should weigh 30-50g and be 8-12cm in length, and males should weigh 40-60g and be 10-15cm in length. Place the broodstock in temporary rearing ponds for temporary rearing. The water temperature in the temporary rearing ponds should be controlled at 22-26°C, salinity 1-3‰, dissolved oxygen ≥5mg / L, and light intensity ≤200lx. The temporary rearing density should be 8-12 broodstock / ㎡. Feed them with an appropriate amount of fresh fish and snail and clam meat bait daily, at a feed rate of 3%-5% of their body weight.

[0013] S2 intensive broodstock cultivation: After 7-10 days of temporary rearing, the broodstock are transferred to intensive rearing ponds, with males and females reared in separate ponds. The water temperature in the rearing ponds is maintained at 24-28°C, a salinity of 2-4‰, dissolved oxygen ≥6mg / L, and a light intensity of 300-500lx. The broodstock are fed a compound feed containing 35%-40% protein, along with fresh Artemia and Daphnia, twice a day, with the morning feeding accounting for 40% of the daily feed amount and the afternoon feeding accounting for 60%. The feed amount is 5%-8% of the broodstock body weight, and is adjusted in time according to feeding conditions.

[0014] S3 Mating and spawning management: When the gonads of the broodstock mature, place the male and female broodstock in a 1:1 ratio in the mating pond. Set up shelters in the mating pond, such as tiles or bamboo tubes. The water temperature should be controlled at 26-30°C, the light intensity should be 500-800 l x, and the dissolved oxygen should be ≥7 mg / L. Observe the mating status of the broodstock daily. When female broodstock are found to be carrying eggs, transfer them to the spawning pond in a timely manner. The environmental conditions in the spawning pond should be consistent with those in the mating pond, and the female broodstock should be allowed to complete spawning in the spawning pond.

[0015] S4 Hatching Environment Control: After the female shrimp lays eggs, the eggs are removed from the abdomen of the female shrimp and placed in the hatching pond for incubation. The water temperature in the hatching pond is controlled at 27-31°C, salinity 3-5‰, dissolved oxygen ≥8mg / L, pH 7.5-8.5, and light intensity 800-1000lx. During the incubation process, the water quality is regularly tested and the water is replaced every two days with a water replacement volume of 1 / 3-1 / 2 of the pond water. At the same time, a micro-flow water circulation system is used to maintain a water flow rate of 0.1-0.3m / s.

[0016] S5 Larvae Grading and Cultivation: When the larvae are hatched, they enter the stage of zoeae cultivation. The water temperature of the cultivation pond is 28-32℃, the salinity is 4-6‰, the dissolved oxygen is ≥8mg / L, the pH value is 7.8-8.8, and the cultivation density is 100,000-150,000 / ㎡. In the first 3 days, they are fed with single-cell algae, such as Chlorella and diatoms, 3-4 times a day, and the feeding amount is 50,000-100,000 cells / mL each time. After 3 days, Artemia nauplii are added, and the feeding amount is 1-2 / mL, and they are fed 2-3 times a day. When the zoeae develop into stage I larvae, the first grading is carried out and the larvae are transferred to The shrimp larvae rearing pond has a water temperature of 28-30℃, a salinity of 2-4‰, a dissolved oxygen ≥7mg / L, a pH value of 7.5-8.5, a rearing density of 50,000-80,000 tails / ㎡, and is fed with a compound feed containing 40%-45% protein, 3-4 times a day, and the feeding amount is 8%-10% of the shrimp larvae body weight; when the shrimp larvae reach 1-1.5cm in length, a second classification is carried out, and the rearing density is adjusted to 30,000-50,000 tails / ㎡, and the above compound feed is continued to be fed, and a small amount of chopped fresh fish is added, and the feed is fed 2-3 times a day until the shrimp larvae reach 3-5cm in length, completing the seedling rearing.

[0017] Preferably, the temporary holding pond, intensive cultivation pond, mating pond, spawning pond and hatching pond are all disinfected before use. The disinfection method is: soaking them in a 20-30 mg / L bleaching powder solution for 24 hours and then rinsing them with clean water.

[0018] Preferably, when selecting the broodstock, the integrity of the limbs of the broodstock should also be checked. The female broodstock should have complete walking legs and chelicerae, the male broodstock should have thick and undamaged chelicerae, and the gonads should be brown or orange in appearance, plump and with clear outlines.

[0019] Preferably, during the intensive cultivation period, a probiotic preparation, such as EM bacteria and Bacillus, is sprayed into the cultivation pool once a week at a concentration of 5-10 g / m2 to improve water quality and regulate intestinal flora.

[0020] Preferably, the density of the shelters in the mating pond is 5-8 per square meter, and the spacing between the shelters is 20-30 cm, so as to ensure that the broodstock have enough space for activities and hiding places.

[0021] Preferably, during the incubation process, the development of the eggs is monitored regularly every day, and when dead eggs or moldy eggs are found, they are sucked out with a straw in time to prevent contamination of other eggs.

[0022] Preferably, during the zoeae-like larvae cultivation stage, an air stone is provided in the cultivation pool for aeration so that the pool water is in a slightly boiling state to ensure sufficient dissolved oxygen.

[0023] Preferably, during the shrimp larvae cultivation period, the remaining bait and feces at the bottom of the pond are cleaned every 3 days, and the water is replaced once a week with the amount of water changed being 1 / 2-2 / 3 of the pond water to keep the water quality fresh.

[0024] Preferably, during the graded cultivation process, a screen is used for classification, and the aperture of the screen is selected according to the body length of the shrimp larvae. The first classification uses a screen with an aperture of 0.5-0.8 mm, and the second classification uses a screen with an aperture of 1.0-1.5 mm.

[0025] Preferably, during the entire breeding and seedling raising process, the red claw crayfish is regularly subjected to disease control, and a 1-2 mg / L povidone iodine solution is sprayed throughout the pond once every 10-15 days. At the same time, vitamin C and immune enhancers are added to the feed, with the added amounts being 0.1%-0.2% and 0.05%-0.1% of the feed weight, respectively, to improve the immunity and disease resistance of the red claw crayfish.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. Broodstock quality assurance and gonadal development optimization

[0028] Precise broodstock selection criteria (weight, body length, appendage integrity, and gonad appearance) ensure that the broodstock are strong in physique and reproductive capacity, thus improving the quality of their offspring from the source.

[0029] Environmental regulation and nutrient supply in stages:

[0030] During the temporary rearing stage, suitable water temperature (22-26°C), low salinity (1-3‰) and low light intensity (≤200lx) are used to reduce the stress of the broodstock and stabilize their physiological state.

[0031] During the intensive breeding stage, the water temperature (24-28℃), salinity (2-4‰) and light intensity (300-500lx) are increased, and high-protein compound feed (35%-40%) and fresh bait (artemia, water fleas) are used. Probiotics (EM bacteria, Bacillus) are added to improve the intestinal flora, significantly promote the maturation of gonads, shorten the breeding cycle, and improve the quality of eggs.

[0032] 2. Improved mating and egg-laying efficiency

[0033] The mating pool is equipped with shelters (5-8 shelters / ㎡, with a spacing of 20-30cm) to provide a safe mating environment for the broodstock, reduce mutual interference, and improve the success rate of mating;

[0034] Transfer female shrimps carrying eggs to spawning ponds with consistent conditions in a timely manner to avoid the impact of environmental fluctuations in the mating pond on spawning, ensure the stability of the spawning process, and reduce the damage rate of eggs.

[0035] 3. Refined control of the incubation environment

[0036] Strict incubation parameters (water temperature 27-31°C, salinity 3-5‰, dissolved oxygen ≥8mg / L) and micro-flow water circulation system (flow rate 0.1-0.3m / s) simulate the natural incubation environment, improve the metabolic efficiency and oxygen supply of eggs, and significantly increase the hatchability.

[0037] Clean dead and moldy eggs regularly to prevent the spread of pollution, ensure the development environment of healthy eggs, and reduce the risk of disease transmission.

[0038] 4. Larval grading and growth optimization

[0039] Phased feeding strategy: unicellular algae (Chlorella, diatoms) are initially fed to zoeae, and Artemia nauplii are added after 3 days to meet the nutritional needs of different developmental stages and promote rapid growth of the larvae;

[0040] Grading screening and density control: Using screens of different apertures (0.5-0.8mm for the first screening and 1.0-1.5mm for the second screening) based on body length to avoid competition and cannibalism caused by individual differences. At the same time, by adjusting the breeding density (gradually reducing from 100,000-150,000 fish / ㎡ to 30,000-50,000 fish / ㎡), the living space is optimized and the survival rate is improved.

[0041] Water quality management and aeration: Air stones are installed in the breeding pond to maintain a slightly boiling state, and leftover bait and feces are cleaned regularly (once every 3 days), and new water is replaced (1 / 2-2 / 3 of the water volume) to ensure sufficient dissolved oxygen (≥7mg / L) and fresh water quality, reduce the accumulation of harmful substances, and provide a stable growth environment for the larvae.

[0042] 5. Disease prevention and control and immunity enhancement

[0043] Full-process disinfection measures (immersion in 20-30mg / L bleach) kill pathogenic microorganisms and cut off the transmission pathways of diseases;

[0044] Regularly spray povidone-iodine solution (1-2 mg / L) and add vitamin C and immune enhancers to the feed to improve shrimp immunity, reduce the occurrence of bacterial and viral diseases, and reduce mortality during the seedling period.

[0045] 6. Overall efficiency improvement

[0046] The present invention achieves the goals of high survival rate of parent shrimps, good synchronization of gonad development, high mating and spawning efficiency, high hatching rate, fast growth of juveniles and uniform specifications during the breeding and seedling raising process of red claw crayfish, provides a scientific and efficient technical solution for large-scale seedling raising, significantly reduces breeding costs, and improves the economic benefits of the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they provide further detailed explanation, but do not constitute a limitation of the present invention.

[0048] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0050] Example 1

[0051] Method for breeding and raising red claw crayfish

[0052] Broodstock Selection and Temporary Rearing (S1): Select broodstock weighing 35-45g for females and 9-11cm in length, and 45-55g for males and 12-14cm in length. Check for appendage integrity (female ambulacral and chelicerae intact, male chelicerae robust and undamaged), and ensure that the gonads are brown and plump. Pre-arrange the ponds in advance with a 25mg / L bleach solution for 24h, rinse with clean water, and refill. Control the water temperature at 24°C, salinity at 2‰, dissolved oxygen at 6mg / L, and light intensity at 150lx. Stock the ponds at a density of 10 broodstock / m2. Feed fresh fish daily at 4% of the broodstock's body weight.

[0053] After 8 days of intensive rearing (S2), broodstock were transferred to intensive rearing ponds, with males and females separated. The water temperature in the rearing ponds was 26°C, the salinity was 3‰, the dissolved oxygen level was 7 mg / L, and the light intensity was 400 lx. The broodstock were fed a 38% protein formula feed supplemented with Artemia spp. at a daily feed rate of 6% (40% in the morning and 60% in the afternoon). EM bacteria (8g / m2) were sprayed weekly to improve water quality.

[0054] Mating and spawning management (S3): After gonadal mating, female shrimp were placed in a mating tank at a ratio of 1:1. Six tiles were placed per m2 (25 cm apart). The water temperature was 28°C, the light intensity was 600 lx, and the dissolved oxygen level was 7.5 mg / L. Female shrimp were found to be carrying eggs and were transferred to the spawning tank in the same environment.

[0055] Incubation Environment Control (S4): Eggs were transferred to hatchery tanks with a water temperature of 29°C, a salinity of 4‰, a dissolved oxygen of 8.5 mg / L, a pH of 8.0, and a light intensity of 900 lx. Half of the water was replaced every two days, and the micro-flow rate was 0.2 m / s. Larvae Grading (S5): Zebrafish were reared in a water temperature of 30°C and a salinity of 5‰. For the first three days, they were fed Chlorella (80,000 cells / mL, four times a day). Three days later, Artemia (1.5 cells / mL, three times a day) was added. Stage I larvae were graded using a 0.6 mm sieve and transferred to a rearing tank with a water temperature of 29°C and a salinity of 3‰ (density of 60,000 larvae / m2). They were fed a 42% protein formula feed (feeding rate of 9%, three times a day). At a body length of 1.2 cm, they were graded again using a 1.2 mm sieve (density of 40,000 larvae / m2). Chopped fish were added twice a day until they reached a body length of 4 cm.

[0056] Example 2

[0057] Method for breeding and raising red claw crayfish

[0058] Selection and temporary rearing of broodstock (S1): Females weigh 30-50g and are 8-12cm long; males 40-60g and 10-15cm long. Their appendages are intact, and their gonads are plump and orange-red. The temporary rearing pond is disinfected (using 20mg / L bleaching powder), with a water temperature of 22°C, a salinity of 1‰, a dissolved oxygen concentration of 5mg / L, and a light intensity of 200lx. The pond is stocked with 12 broodstock / ㎡ and fed with snail and mussel meat (3% of the feed intake).

[0059] The intensive cultivation of broodstock (S2) was temporarily carried out for 10 days before being transferred to a new pond with a water temperature of 28°C, a salinity of 4‰, a dissolved oxygen of 6 mg / L, and a light intensity of 500 lx. The broodstock were fed with 40% protein feed + Daphnia, with a daily feeding amount of 8% (40% in the morning and 60% in the afternoon), and Bacillus spores (5 g / ㎡) were sprayed weekly.

[0060] Mating and spawning management (S3): The mating pond was set up with eight bamboo tubes per m2 (20 cm apart). The water temperature was 30°C, the light intensity was 800 l x 1, and the dissolved oxygen level was 7 mg / L. Female shrimp carrying eggs were transferred to the spawning pond. Egg development was observed daily, and any dead eggs were removed promptly with a straw.

[0061] Incubation environment control (S4): The water temperature of the incubation pool was 31°C, the salinity was 5‰, the dissolved oxygen was 8 mg / L, the pH was 8.5, the light intensity was 1000 lx, the water exchange volume was 1 / 3 (2 days / time), and the water flow rate was 0.3 m / s.

[0062] Larval grading (S5) The water temperature for zoeae larvae is 32°C and the salinity is 6‰. The water is aerated to a slight boil. Diatoms (50,000 cells / mL, 3 times / day) are fed for the first 3 days, followed by Artemia (2 cells / mL, 2 times / day). Stage I larvae are graded using a 0.5mm sieve (density 50,000 larvae / m2, water temperature 28°C, salinity 2‰) and fed a 45% protein feed (10% of the feed amount, 4 times / day). When the larvae reach 1.5cm in length, they are graded again using a 1.5mm sieve (density 30,000 larvae / m2), and minced fish are added (3 times / day) to raise them to 5cm larvae.

[0063] Example 3

[0064] Method for breeding and raising red claw crayfish

[0065] Selection and temporary rearing of broodstock (S1) Strictly select broodstock with complete appendages and brown gonads (female 40g, body length 10cm; male 50g, body length 13cm), disinfect the temporary rearing pond (30mg / L bleaching powder), water temperature 26℃, salinity 3‰, dissolved oxygen 5.5mg / L, light 100lx, density 8 tails / ㎡, feed miscellaneous fish + snail and clam meat (feeding amount 5%).

[0066] The intensive cultivation of broodstock (S2) was temporarily carried out for 7 days before being transferred to a new pond with a water temperature of 24°C, a salinity of 2‰, a dissolved oxygen of 6.5 mg / L, and a light intensity of 300 lx. The broodstock were fed with 35% protein feed + Artemia, with a daily feeding amount of 5% (40% in the morning and 60% in the afternoon), and EM bacteria (10 g / m2) were sprayed every week.

[0067] Mating and spawning management (S3) The density of shelters in the mating pool was 5 pieces / m2 (tiles, 30 cm apart), the water temperature was 26°C, the light intensity was 500 lx, and the dissolved oxygen was 7 mg / L. The shrimps with eggs were moved to the spawning pool in time.

[0068] Incubation environment control (S4): The incubation pond water temperature was 27°C, salinity was 3‰, dissolved oxygen was 8 mg / L, pH was 7.5, and light intensity was 800 lx. Moldy eggs were regularly vacuumed out, and the water volume was changed by 1 / 2 every two days. The water flow was 0.1 m / s. Larval grading (S5): The water temperature for zoeae larvae was 28°C, salinity was 4‰, and oxygen was supplied by aeration. For the first three days, they were fed Chlorella vulgaris (100,000 cells / mL, three times a day), followed by Artemia (1 cell / mL, three times a day). Stage I larvae were graded using a 0.8 mm sieve (density 80,000 larvae / m2, water temperature 30°C, salinity 4‰) and fed a 40% protein diet (8% of the total protein content, three times a day). At 1 cm in length, larvae were graded again using a 1.0 mm sieve (density 50,000 larvae / m2). Residual bait was removed daily from the pond bottom, and two-thirds of the water was changed weekly. The larvae were eventually raised to 3 cm in length.

[0069] Example 4

[0070] Method for breeding and raising red claw crayfish

[0071] Broodstock selection and temporary rearing (S1) Broodstock weighing 50 g females and 12 cm in length, and 60 g males and 15 cm in length, were selected. They had intact appendages and plump, well-defined gonads. The temporary rearing pond was disinfected and maintained at a water temperature of 25°C, a salinity of 2.5‰, a dissolved oxygen concentration of 5 mg / L, and a light intensity of 180 lx. The density was 11 per m2, and the feed was snail and mussel meat (4% of the feed allowance).

[0072] The intensive cultivation of broodstock (S2) was temporarily carried out for 9 days before being transferred to a new pond with a water temperature of 27°C, a salinity of 3.5‰, a dissolved oxygen of 6 mg / L, and a light intensity of 450 lx. The broodstock were fed with 38% protein feed + Daphnia, with a daily feeding amount of 7%, and Bacillus spores (7 g / ㎡) were sprayed weekly.

[0073] Mating and spawning management (S3) The mating pond was set up with 7 bamboo tubes per m2 (spacing 25 cm), water temperature 29℃, light 700lx, dissolved oxygen 7.5mg / L, and the shrimps with eggs were moved to the spawning pond with the same environment.

[0074] Incubation environment control (S4): The incubation pond water temperature was 30°C, salinity was 4.5‰, dissolved oxygen was 8.5 mg / L, pH was 8.2, and light intensity was 950 lx. One-third of the water was replaced every two days, and the water flow was 0.25 m / s. Egg development was monitored daily. Larval stage culture (S5): The water temperature for zoeae was 31°C, salinity was 5.5‰, and the water was aerated and slightly boiling. Diatoms (60,000 cells / mL, four times a day) were fed for the first three days, followed by Artemia (1.8 cells / mL, two times a day). Stage I larvae were graded using a 0.7 mm mesh (density 70,000 prawns / m2, water temperature 28°C, salinity 3‰), and fed a 43% protein diet (9% of the total feed intake, four times a day). When the body length reaches 1.3 cm, the shrimp are graded twice using a 1.3 mm sieve (density 40,000 / m2), minced fish are added (twice a day), 1.5 mg / L povidone iodine is sprayed throughout the pond every 10 days, 0.15% vitamin C and 0.08% immune enhancer are added to the feed, and the shrimp are raised to 4.5 cm fry.

[0075] Comparative Example 1 (no graded cultivation)

[0076] Selection and temporary rearing of broodstock: Same as in Example 1, but no grading was performed during the larval rearing stage.

[0077] Zebrafish rearing: The density was maintained at 150,000 / m2. The first stage larvae were not transferred and continued to be reared in the original pond without adjusting the density and screen grading.

[0078] Results: When the shrimp larvae were 1 cm long, the high density (150,000 / m2) led to insufficient dissolved oxygen (<7 mg / L), resulting in a larval survival rate of only 45%, a significant decrease in growth rate (body length was only 2 cm after 30 days, an average of 4 cm in the example), and the accumulation of residual bait caused the water quality to deteriorate.

[0079] Comparative Example 2 (no probiotics and disease control)

[0080] Selection and temporary rearing of broodstock: Same as in Example 2, except that probiotics were not sprayed during the intensive rearing period, and disease control was not performed throughout the entire process.

[0081] Key differences: S2 does not contain EM bacteria / Bacillus, S10 is not disinfected with povidone iodine, and vitamin C and immune enhancers are not added to the feed.

[0082] Results: From the second week of intensive cultivation, the ammonia nitrogen concentration in the cultivation pond exceeded the standard (>0.5 mg / L), and the feeding rate of the broodstock decreased by 15%; Vibrio disease broke out in the larval cultivation stage, and the mortality rate of the larvae reached 60%. The size of the surviving individuals varied greatly (body length 1-3 cm), and the disease resistance was significantly lower than that of the example group.

[0083] The above four groups of examples and two groups of comparative examples were compared in terms of parent shrimp feeding rate, juvenile shrimp growth rate, postlarval shrimp mortality rate, surviving individual size differences and water quality, as shown in the following table:

[0084]

[0085] Data Description

[0086] Feeding rate of broodstock: In Example 2, the feeding rate was stabilized at over 90% through probiotic regulation and precise feeding; in Comparative Example 2, the feeding rate decreased by 15% due to deterioration of water quality.

[0087] Juvenile shrimp growth rate: Graded cultivation (Example) through density control and nutrition optimization, the average body length of 30 days is 3.5-5.0cm; Comparative Example 1 is inhibited by excessive density (150,000 tails / ㎡), and Comparative Example 2 has a significantly reduced growth rate due to disease.

[0088] Postlarvae mortality: The mortality rate of the embodiment was controlled at 15%-20% through water quality management and grading operations; the mortality rate of the control group exceeded 55% due to high density or disease outbreaks.

[0089] Size differences of surviving individuals: In the embodiment, size was homogenized by sieve grading (0.5-1.5 mm aperture), with a difference of ≤±0.6 cm; in the control group, size differences were 2-3 cm for the ungraded or disease-unprotected samples.

[0090] Water quality: The embodiment maintained excellent water quality by regular water changes (1 / 3-2 / 3), micro-flow water (0.1-0.3m / s) and probiotics (5-10g / ㎡); the control group experienced insufficient dissolved oxygen, excessive ammonia nitrogen (>0.5mg / L) and pathogen infection.

[0091] Advantages of the red claw crayfish breeding and seedling raising method of the present invention:

[0092] 1. Broodstock quality assurance and gonadal development optimization

[0093] Precise broodstock selection criteria (weight, body length, appendage integrity, and gonad appearance) ensure that the broodstock are strong in physique and reproductive capacity, thus improving the quality of their offspring from the source.

[0094] Environmental regulation and nutrient supply in stages:

[0095] During the temporary rearing stage, suitable water temperature (22-26°C), low salinity (1-3‰) and low light intensity (≤200lx) are used to reduce the stress of the broodstock and stabilize their physiological state.

[0096] During the intensive breeding stage, the water temperature (24-28℃), salinity (2-4‰) and light intensity (300-500lx) are increased, and high-protein compound feed (35%-40%) and fresh bait (artemia, water fleas) are used. Probiotics (EM bacteria, Bacillus) are added to improve the intestinal flora, significantly promote the maturation of gonads, shorten the breeding cycle, and improve the quality of eggs.

[0097] 2. Improved mating and egg-laying efficiency

[0098] The mating pool is equipped with shelters (5-8 shelters / ㎡, with a spacing of 20-30cm) to provide a safe mating environment for the broodstock, reduce mutual interference, and improve the success rate of mating;

[0099] Transfer female shrimps carrying eggs to spawning ponds with consistent conditions in a timely manner to avoid the impact of environmental fluctuations in the mating pond on spawning, ensure the stability of the spawning process, and reduce the damage rate of eggs.

[0100] 3. Refined control of the incubation environment

[0101] Strict incubation parameters (water temperature 27-31°C, salinity 3-5‰, dissolved oxygen ≥8mg / L) and micro-flow water circulation system (flow rate 0.1-0.3m / s) simulate the natural incubation environment, improve the metabolic efficiency and oxygen supply of eggs, and significantly increase the hatchability.

[0102] Clean dead and moldy eggs regularly to prevent the spread of pollution, ensure the development environment of healthy eggs, and reduce the risk of disease transmission.

[0103] 4. Larval grading and growth optimization

[0104] Phased feeding strategy: unicellular algae (Chlorella, diatoms) are initially fed to zoeae, and Artemia nauplii are added after 3 days to meet the nutritional needs of different developmental stages and promote rapid growth of the larvae;

[0105] Grading screening and density control: Using screens of different apertures (0.5-0.8mm for the first screening and 1.0-1.5mm for the second screening) based on body length to avoid competition and cannibalism caused by individual differences. At the same time, by adjusting the breeding density (gradually reducing from 100,000-150,000 fish / ㎡ to 30,000-50,000 fish / ㎡), the living space is optimized and the survival rate is improved.

[0106] Water quality management and aeration: Air stones are installed in the breeding pond to maintain a slightly boiling state, and leftover bait and feces are cleaned regularly (once every 3 days), and new water is replaced (1 / 2-2 / 3 of the water volume) to ensure sufficient dissolved oxygen (≥7mg / L) and fresh water quality, reduce the accumulation of harmful substances, and provide a stable growth environment for the larvae.

[0107] 5. Disease prevention and control and immunity enhancement

[0108] Full-process disinfection measures (immersion in 20-30mg / L bleach) kill pathogenic microorganisms and cut off the transmission pathways of diseases;

[0109] Regularly spray povidone-iodine solution (1-2 mg / L) and add vitamin C and immune enhancers to the feed to improve shrimp immunity, reduce the occurrence of bacterial and viral diseases, and reduce mortality during the seedling period.

[0110] 6. Overall efficiency improvement

[0111] Through the integration of the above technologies, the present invention achieves the goals of high survival rate of parent shrimps, good synchronization of gonad development, high mating and spawning efficiency, high hatching rate, fast growth of juveniles and uniform specifications during the reproduction and seedling raising of red claw crayfish, providing a scientific and efficient technical solution for large-scale seedling raising, significantly reducing breeding costs and improving the economic benefits of the industry.

[0112] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for breeding and raising red claw crayfish, characterized in that: The specific steps include: S1. Selection and temporary rearing of broodstock: Select red claw crayfish with a strong physique, intact appendages, no injuries, strong vitality, and well-developed gonads as broodstock. Females should weigh 30-50g and be 8-12cm in length, and males should weigh 40-60g and be 10-15cm in length. Place the broodstock in temporary rearing ponds for temporary rearing. The water temperature in the temporary rearing ponds should be controlled at 22-26°C, salinity 1-3‰, dissolved oxygen ≥5mg / L, and light intensity ≤200lx. The temporary rearing density should be 8-12 broodstock / ㎡. Feed them with an appropriate amount of fresh fish and snail and clam meat bait daily, at a feed rate of 3%-5% of their body weight. S2 intensive broodstock cultivation: After 7-10 days of temporary rearing, the broodstock are transferred to intensive rearing ponds, with males and females reared in separate ponds. The water temperature in the rearing ponds is maintained at 24-28°C, a salinity of 2-4‰, dissolved oxygen ≥6mg / L, and a light intensity of 300-500lx. The broodstock are fed a compound feed containing 35%-40% protein, along with fresh Artemia and Daphnia, twice a day, with the morning feeding accounting for 40% of the daily feed amount and the afternoon feeding accounting for 60%. The feed amount is 5%-8% of the broodstock body weight, and is adjusted in time according to feeding conditions. S3 Mating and spawning management: When the gonads of the broodstock mature, place the male and female broodstock in a 1:1 ratio in the mating pond. Set up shelters in the mating pond, such as tiles or bamboo tubes. The water temperature should be controlled at 26-30°C, the light intensity should be 500-800 l x, and the dissolved oxygen should be ≥7 mg / L. Observe the mating status of the broodstock daily. When female broodstock are found to be carrying eggs, transfer them to the spawning pond in a timely manner. The environmental conditions in the spawning pond should be consistent with those in the mating pond, and the female broodstock should be allowed to complete spawning in the spawning pond. S4 Hatching Environment Control: After the female shrimp lays eggs, the eggs are removed from the abdomen of the female shrimp and placed in the hatching pond for incubation. The water temperature in the hatching pond is controlled at 27-31°C, salinity 3-5‰, dissolved oxygen ≥8mg / L, pH 7.5-8.5, and light intensity 800-1000lx. During the incubation process, the water quality is regularly tested and the water is replaced every two days with a water replacement volume of 1 / 3-1 / 2 of the pond water. At the same time, a micro-flow water circulation system is used to maintain a water flow rate of 0.1-0.3m / s. S5 Larvae Grading and Cultivation: When the larvae are hatched, they enter the stage of zoeae cultivation. The water temperature of the cultivation pond is 28-32℃, the salinity is 4-6‰, the dissolved oxygen is ≥8mg / L, the pH value is 7.8-8.8, and the cultivation density is 100,000-150,000 / ㎡. In the first 3 days, they are fed with single-cell algae, such as Chlorella and diatoms, 3-4 times a day, and the feeding amount is 50,000-100,000 cells / mL each time. After 3 days, Artemia nauplii are added, and the feeding amount is 1-2 / mL, and they are fed 2-3 times a day. When the zoeae develop into stage I larvae, the first grading is carried out and the larvae are transferred to The shrimp larvae rearing pond has a water temperature of 28-30℃, a salinity of 2-4‰, a dissolved oxygen ≥7mg / L, a pH value of 7.5-8.5, a rearing density of 50,000-80,000 tails / ㎡, and is fed with a compound feed containing 40%-45% protein, 3-4 times a day, and the feeding amount is 8%-10% of the shrimp larvae body weight; when the shrimp larvae reach 1-1.5cm in length, a second classification is carried out, and the rearing density is adjusted to 30,000-50,000 tails / ㎡, and the above compound feed is continued to be fed, and a small amount of chopped fresh fish is added, and the feed is fed 2-3 times a day until the shrimp larvae reach 3-5cm in length, completing the seedling rearing.

2. The method for breeding and raising red claw crayfish according to claim 1, wherein: The temporary holding pond, intensive cultivation pond, mating pond, spawning pond and hatching pond all need to be disinfected before use. The disinfection method is: soak them in 20-30 mg / L bleach solution for 24 hours and then rinse them with clean water.

3. The method for breeding and raising red claw crayfish according to claim 1, wherein: When selecting the broodstock, the integrity of the limbs of the broodstock must also be checked. The female broodstock must have complete walking legs and chelicerae, while the male broodstock must have strong and undamaged chelicerae. The gonads must be brown or orange in appearance, plump, and clearly defined.

4. The method for breeding and raising red claw crayfish according to claim 1, wherein: During the intensive cultivation period, a probiotic preparation, such as EM bacteria and Bacillus, is sprayed into the cultivation pool once a week at a concentration of 5-10 g / m2 to improve water quality and regulate intestinal flora.

5. The method for breeding and raising red claw crayfish according to claim 1, characterized in that: The density of the shelters in the mating pond is 5-8 per square meter, and the spacing between the shelters is 20-30 cm to ensure that the broodstock have enough space for activities and hiding places.

6. The method for breeding and raising red claw crayfish according to claim 1, characterized in that: During the incubation process, the development of the eggs is monitored regularly every day. When dead eggs or moldy eggs are found, they are sucked out with a straw in time to prevent contamination of other eggs.

7. The method for breeding and raising red claw crayfish according to claim 1, characterized in that: During the zoeae larvae cultivation stage, an air stone is provided in the cultivation pond for aeration so that the pond water is in a slightly boiling state to ensure sufficient dissolved oxygen.

8. The method for breeding and raising red claw crayfish according to claim 1, characterized in that: During the shrimp larvae cultivation period, the remaining bait and feces at the bottom of the pond are cleaned every 3 days, and the water is replaced once a week with the amount of water replaced being 1 / 2-2 / 3 of the pond water to keep the water quality fresh.

9. The method for breeding and raising red claw crayfish according to claim 1, characterized in that: During the graded cultivation process, a screen is used for grading, and the aperture of the screen is selected according to the body length of the shrimp larvae. The first grading uses a screen with an aperture of 0.5-0.8 mm, and the second grading uses a screen with an aperture of 1.0-1.5 mm.

10. The method for breeding and raising red claw crayfish according to claim 1, characterized in that: During the entire breeding and seedling raising process, red claw crayfish are regularly subjected to disease prevention and control. The entire pond is sprayed with 1-2 mg / L povidone iodine solution once every 10-15 days. At the same time, vitamin C and immune enhancers are added to the feed, with the added amounts being 0.1%-0.2% and 0.05%-0.1% of the feed weight respectively, to improve the immunity and disease resistance of red claw crayfish.

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