Method for improving survival rate of juvenile eriocheir sinensis in early cultivation

Abstract

The invention relates to the technical field of Chinese mitten crab seed cultivation, in particular to a method for increasing the survival rate of Chinese mitten crab seed early cultivation, which comprises three key steps of pond design, equipment arrangement and juvenile crab cultivation. Pond structural design is optimized, special breeding equipment is configured, and staged refined breeding management is implemented, so that the growth requirements of the fries are accurately matched with the environment and bait; planting blocks and bait and fertilizer blocks are arranged at intervals in the pond, aquatic plant cultivation and water body pretreatment are matched, the equipment comprises a lamp belt with a bait gathering function and manual and automatic double feeders matched with different breeding stages, and bait types and feeding modes are switched according to the seedling development stage in the breeding process; the method effectively solves the survival adaptation problem of the offspring seeds in the metamorphosis shelling period and the feeding habit conversion period, is suitable for large-scale early-stage cultivation of the eriocheir sinensis offspring seeds, and has good industrial application value and popularization prospects.

Description

Technical Field

[0001] This invention relates to the field of Chinese mitten crab seedling cultivation technology, specifically to a method for improving the early survival rate of Chinese mitten crab seedlings. Background Technology

[0002] As an important freshwater economic crab species in my country, the Chinese mitten crab relies on multiple molts for its growth and development. Molting is not only a marker of morphological metamorphosis but also a crucial step in individual growth. From hatching of fertilized eggs to adult crab farming, the Chinese mitten crab goes through several developmental stages, including zoea larvae, megalopa larvae, juvenile crabs, and baby crabs. Among these, the early cultivation stage from megalopa larvae to baby crabs is the core link that determines the survival rate of seedlings and the subsequent farming benefits.

[0003] In natural and traditional rearing environments, megalopa larvae are tiny, strong swimmers, and have a preference for freshwater, primarily feeding on zooplankton for growth. After molting into juvenile crabs, they lose their swimming ability and adopt a climbing lifestyle, shifting their diet from zooplankton to algae and artificial feed. This process presents the larvae with a dual challenge: firstly, insufficient or unevenly distributed zooplankton in the pond can hinder their growth due to feeding difficulties; secondly, the sudden change in their diet and habitat during the juvenile stage can easily lead to growth stagnation or even death if they cannot obtain suitable food and habitat in time.

[0004] Current breeding methods often employ a single-structure pond layout, lacking functional zoning to meet the needs of different seedling stages. Feed supply methods are inefficient, failing to accurately match the dietary changes from megalopa larvae to juveniles. Furthermore, the lack of guidance for seedlings to congregate and feed leads to low feed utilization and uneven feeding. These problems collectively result in a generally low survival rate for juvenile Chinese mitten crabs, severely hindering the large-scale and efficient development of the Chinese mitten crab aquaculture industry. Therefore, this paper proposes a method to improve the early-stage survival rate of Chinese mitten crab seedlings in order to address these issues. Summary of the Invention

[0005] This invention addresses the technical problems existing in the prior art by providing a method to improve the early cultivation survival rate of Chinese velvet seedlings.

[0006] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for improving the early survival rate of Chinese mitten crab seedlings, comprising three key steps: pond design, equipment setup, and juvenile crab rearing. Step 1: Pond Design: Select a pond with a flat bottom and maintain a stable water depth during the rearing period. Before stocking the crab larvae, carry out the following operations in sequence: bottom drying, zoning planning, aquatic plant cultivation, and water body cultivation. First, flatten the bottom of the pond and then dry it until fine cracks appear on the bottom. Then, divide the bottom of the pond into alternating planting blocks and feed / fertilizer blocks, maintaining a specific width ratio between the planting blocks and the feed / fertilizer blocks. Plant aquatic plants in the planting blocks at a predetermined time before the crab larvae are stocked, and control the water level at a shallow depth during planting. Apply fertilizer to the feed / fertilizer blocks at another predetermined time before the crab larvae are stocked, and raise the water depth to a suitable range during fertilization. Step Two: Equipment Setup: This includes light strips and feeders. The light strips are laid between two planting blocks on the bottom of the water and are turned on at specific times according to the diurnal rhythm. The feeders include manual and automatic feeders. The manual feeder consists of a booster, a first feed hopper, a connecting pipe, a first feeding pipe, and a sealing device. The booster is a piston-type pressurization component that pressurizes the first feed hopper through a lever structure. The first feeding pipe is made of elastic material with micro-cracks on its surface and is laid in the bait and fertilizer block area on the bottom of the water. The sealing device is a vertical tubular structure with a ring-shaped component with a small opening at its top, which is fitted with a sealing ball composed of a float, a vertical rod, and a cover. The automatic feeder consists of a second feed hopper, a connecting pipe, a water pump, and a second feeding pipe. The second feed hopper is connected to the water pump inlet via the connecting pipe, and the water pump outlet is connected to the second feeding pipe. The second feeding pipe is made of buoyant material with a triangular cross-section and multiple spray holes at the top of the pipe. The second feeding pipe is located above the light strip. Step 3: Crab rearing: After the megalopa larvae are released, they are fed liquid feed by manual feeders during the day; at night, the light strips are turned on, and when the number of specific organisms in the light strip area is significantly reduced, the liquid feed feeding is stopped and the automatic feeder is switched to feed pellet feed, and the feeding frequency is controlled according to specific time nodes.

[0007] In a preferred embodiment, the aquatic plants planted in the planting block are submerged plants suitable for the habitat of Chinese mitten crab seedlings and can provide a hiding environment, selected from one or a combination of two of Vallisneria natans and Hydrilla verticillata.

[0008] In a preferred embodiment, the fertilizer applied to the bait block is a mixture of well-rotted organic fertilizer and inorganic fertilizer, which is mixed in a specific mass ratio, and the amount of fertilizer applied is adapted according to the pond area.

[0009] In a preferred embodiment, the light strip is a waterproof LED light strip, and when it is working, the emission wavelength is in the range that attracts plankton. The light strip is laid along the length of the pond, and the spacing between adjacent light strips is kept uniform.

[0010] In a preferred embodiment, the diameter of the first feeding pipe of the manual feeder is matched with the size of the microcracks to ensure that the microcracks close under low pressure and the feed flows out evenly under high pressure; the diameter of the second feeding pipe of the automatic feeder is matched with the size of the spray hole to ensure that the pellet feed can be evenly distributed on the surface of the water after being sprayed out.

[0011] In a preferred embodiment, the liquid feed is a soybean milk-based nutritional feed, and the feeding amount is adjusted according to the number of megalopa larvae released; the pellet feed is a microparticle feed suitable for the consumption of juvenile crabs, and the feeding amount is dynamically adjusted according to the growth stage and feeding situation of the juvenile crabs.

[0012] In a preferred embodiment, the stocking density of megalopa larvae is controlled appropriately, and the salinity and temperature of the water are maintained within the range that the Chinese mitten crab megalopa larvae are adapted to during stocking.

[0013] In a preferred embodiment, water quality indicators are monitored regularly during the cultivation process to maintain dissolved oxygen, pH, ammonia nitrogen, and nitrite levels within the range suitable for seedling growth.

[0014] The beneficial effects of this invention are: 1. This invention, through the functional zoning design of the pond, arranges planting blocks and feed / fertilizer blocks alternately, which not only provides a suitable habitat and molting environment for juvenile crabs, but also ensures the concentration of feed supply, solving the problem of environmental adaptation for seedlings transitioning from swimming to climbing. At the same time, the setting of light strips achieves dual aggregation of seedlings and natural feed, further enhancing the supporting role of the environment for seedling growth.

[0015] 2. This invention addresses the dietary changes of megalopa larvae to juvenile crabs by configuring both manual and automatic feeders to meet the feeding needs of liquid and pelleted feeds, respectively. Through precise design of feeding time and feeding area, it ensures that the seedlings can obtain sufficient and suitable feed at different developmental stages, avoiding insufficient feeding problems caused by dietary changes.

[0016] 3. This invention effectively solves the core survival problems of seedlings during the metamorphosis and molting period and the feeding habit transition period through the synergistic effect of environment, equipment and cultivation management. Compared with traditional cultivation methods, it significantly improves the survival rate of young crabs and produces strong and uniform young crabs, laying a good foundation for subsequent breeding.

[0017] 4. The equipment used in this invention has a simple structure, low manufacturing and maintenance costs, and the steps such as pond treatment and feeding during the cultivation process are easy to master. No complicated professional technology is required. It is suitable for seedling cultivation farms of different sizes and has good prospects for promotion and application. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the overall structure of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the manual feeder of the present invention.

[0020] Figure 3 This is a schematic diagram of the sealing device structure of the manual feeder of the present invention.

[0021] Figure 4 This is a schematic diagram of the sealing structure of the sealing device of the present invention.

[0022] Figure 5 This is a schematic diagram of the automatic feeder structure of the present invention.

[0023] Figure 6 This is a schematic diagram of the second feeding tube structure of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0027] like Figure 1-6 As shown in the figure, this embodiment provides a method for improving the early survival rate of *Eriocheir sinensis* seedlings, comprising the following steps: Step 1: Pond Design: Pond site selection and basic treatment. Select a flat area with sufficient water supply and water quality that meets aquaculture standards to construct the pond. Ensure convenient drainage and irrigation, and adjust the water level according to cultivation needs. Before stocking crab seedlings, clean and disinfect the pond, remove wild fish, predators, and residual silt. Then, level the bottom of the pond to ensure there are no obvious height differences. Then, sun-dry the bottom until fine cracks appear on the bottom to improve the aeration of the pond bottom, reduce the growth of harmful microorganisms, and provide a healthy growth base for the seedlings. The leveled pond bottom is divided into alternating planting blocks and feed / fertilizer blocks, forming functional areas that alternate between "resting" and "feeding". The planting blocks are used to cultivate aquatic plants, providing habitats, hiding places, and molting sites for the juvenile crabs. Their width is set according to the overall size of the pond to ensure sufficient space for the growth of aquatic plants. The feed / fertilizer blocks are used to cultivate natural food and provide artificial feed. Their width is set to a specific multiple of the planting blocks to ensure that the food supply range can cover the activity area of ​​the juveniles, allowing them to feed nearby. Before the crab larvae are released into the pond, aquatic plants are planted in the planting blocks at a predetermined time. Submerged plants suitable for the habitat of Chinese mitten crab larvae are selected. During planting, the pond water level is controlled to be shallow to facilitate the rooting and initial growth of the aquatic plants. After the aquatic plants have grown steadily, mixed fertilizer is applied to the feed and fertilizer area. The fertilizer is a mixture of well-rotted organic fertilizer and inorganic fertilizer in a certain proportion. This can promote the reproduction of plankton, provide natural food for megalopa larvae, and maintain the nutritional balance of the water. When fertilizing, the pond water level is raised to a suitable depth to prepare for the release of the larvae. Step Two: Equipment Setup: Select waterproof LED light strips with wavelengths that are highly attractive to plankton, effectively guiding them to specific areas. Lay the light strips along the gaps between two planting blocks on the bottom of the pond, maintaining a uniform spacing between adjacent strips to ensure that the light covers most of the cultivation area. Set the light strips to be turned on from after dark until dawn. The light effect not only attracts plankton and increases local food abundance but also guides megalopa larvae to feed, reducing the difficulty of predation for the larvae. At the same time, the light promotes the growth of phytoplankton and algae in the water, providing a food source for the subsequent growth of juvenile crabs and forming a virtuous ecological cycle. The manual feeder is mainly suitable for feeding liquid feed to megalopa larvae. It consists of a pressure booster, a first feed tank, a connecting pipe, a first feeding tube, and a sealing device. The pressure booster adopts a piston structure and is equipped with a lever operation component for easy manual pressure application. The first feed tank is used to store liquid feed and has a feeding cover on top for easy replenishment. The first feeding tube is made of elastic rubber with uniformly distributed micro-cracks on its surface. The crack size is precisely designed to remain closed under no or low pressure to prevent water from flowing back into the tube and contaminating the feed. When the pressure booster pressurizes the first feed tank, the tube expands under pressure, the micro-cracks open, and the liquid feed flows out evenly with the water, forming a continuous food band in the feed block area. The sealing device is installed at the end of the first feeding tube. The sealing ball inside its vertical tubular structure can automatically adjust according to changes in the liquid level inside the tube. When there is enough feed in the tube, the float moves the cover to close the tube opening, gradually increasing the pressure inside the tube and ensuring that the feed can be evenly sprayed out from the micro-cracks, achieving precise feeding. The automatic feeder is designed for feeding juvenile crabs with pelleted feed. It consists of a second feed hopper, a connecting pipe, a water pump, and a second feeding pipe. The second feed hopper stores the pelleted feed and does not require high pressure, resulting in a simpler design. The water pump provides power for feed delivery, mixing the pelleted feed in the second feed hopper with water and then delivering it to the second feeding pipe via the connecting pipe. The second feeding pipe is made of a buoyant material and floats on the water surface. Its triangular cross-section ensures pipe stability and facilitates the spread of pelleted feed. Evenly spaced spray holes at the top of the pipe allow the pelleted feed to be sprayed out under water pump pressure, distributing it evenly on the water surface, which is suitable for the climbing and feeding habits of juvenile crabs. The second feeding pipe is positioned above a light strip, which attracts the juvenile crabs to feed, improving feed utilization. Step 3: Raising baby crabs: Initial rearing and management: When stocking megalopa larvae, first test the salinity, water temperature, and other indicators of the pond water to ensure that they meet the range of adaptability for the seedlings, and then put the megalopa larvae into the pond at an appropriate density; during the day, use a manual feeder to feed liquid feed to the feed block area, with soybean milk-based nutritional feed as the main component, to provide sufficient nutrition for the megalopa larvae and promote the growth of plankton in the water; at night, turn on the light strips, using the dual attraction of the light strips to plankton and megalopa larvae to make them gather in the light strip area, which is convenient for the megalopa larvae to feed, improving feeding efficiency and feed utilization; Mid-term transition management: Continuously observe the biological distribution in the light strip area. When a significant decrease in the number of plankton in the light strip area is found, it indicates that the megalopa larvae have basically completed their transition to juvenile crabs. At this time, stop feeding liquid feed and switch to automatic feeders to feed pellet feed. Select a formula for pellet feed that is suitable for the size of the juvenile crabs' mouthparts and nutritional needs. Set the feeding time to noon during the day, half an hour after the light strip is turned on, and half an hour before the light strip is turned off. This not only meets the needs of juvenile crabs to feed on algae and pellet feed on the bait blocks during the day, but also matches their habit of gathering to feed near the light strip at night, so as to achieve a precise match between feeding time and the activity pattern of the seedlings. Post-consolidation management: During the rearing period of juvenile crabs, the water quality indicators of the pond are monitored regularly, including dissolved oxygen, pH value, ammonia nitrogen and nitrite content. Water quality is maintained through measures such as water exchange and oxygenation. At the same time, the molting of juvenile crabs is observed to ensure that the aquatic plant planting blocks can provide a safe molting and hiding place for the juvenile crabs and avoid interference from other crabs or predators during the molting period. After the juvenile crabs have completed multiple molts and grown to a stable size, they can be transferred to the subsequent juvenile crab rearing stage.

[0028] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0029] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0030] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0031] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0032] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0033] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0034] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for improving the survival rate of early culture of Eriocheir sinensis fry, characterized in that, The method comprises three key steps of pond design, equipment setting and crab breeding. The first step is pond design: a pond with a flat bottom is selected, and a stable water depth is maintained during the breeding period; before the crab larvae are released, the bottom is sunned, the area is planned, the water grass is planted, and the water body is cultivated in sequence; the bottom of the pond is first flattened and then treated by sunning until fine cracks appear on the bottom; then the bottom is divided into planting blocks and bait blocks arranged alternately, and the width of the planting blocks and the bait blocks is kept at a certain ratio; the planting blocks are planted with water grass at a predetermined time before the crab larvae are released into the pond, and the water level is controlled during planting; the bait blocks are fertilized at another predetermined time before the crab larvae are released into the pond, and the water depth is increased to an appropriate range during fertilization. The second step is equipment setting: it includes a light strip and a feeder; the light strip is laid between the two planting blocks at the bottom of the water, and is turned on at a specific time according to the day-night rhythm; the feeder includes a manual feeder and an automatic feeder; the manual feeder is composed of a pressure booster, a first barrel, a connecting pipe, a first feeding pipe and a sealing device; the pressure booster is a piston type pressure boosting component, which boosts the pressure in the first barrel through a lever structure; the first feeding pipe is made of elastic material, and has micro cracks on the surface; the first feeding pipe is laid in the bait block area at the bottom of the water; the sealing device is a vertical tubular structure, and has a ring-shaped part with a small opening at the top end; the small opening is connected with a sealing ball composed of a floating ball, a vertical rod and a cover surface; the automatic feeder is composed of a second barrel, a connecting pipe, a water pump and a second feeding pipe; the second barrel is connected with the water inlet end of the water pump through the connecting pipe; the water outlet end of the water pump is connected with the second feeding pipe; the second feeding pipe is made of floating material, and has a triangular cross section; a plurality of feeding holes are formed in the upper end of the pipe body; and the second feeding pipe is arranged above the light strip. The third step is crab breeding: after the large-eyed larvae are released, liquid feed is fed to the larvae by the manual feeder during the day; the light strip is turned on at night; when the number of specific organisms in the light strip area is significantly reduced, the feeding of liquid feed is stopped, and the feeding of granular feed is switched to the automatic feeder; and the feeding frequency is controlled according to a specific time node.

2. The method of claim 1, wherein, The water grass planted in the planting blocks is a submerged plant suitable for the habitat of Chinese mitten crab larvae and can provide a hiding environment, and is selected from one or a combination of two of Myriophyllum spicatum and Hydrilla verticillata.

3. The method of claim 1, wherein, The fertilizer applied to the bait block is a mixed fertilizer of decomposed organic fertilizer and inorganic fertilizer; the organic fertilizer and the inorganic fertilizer are mixed at a specific mass ratio, and the fertilizer amount is adapted according to the area of the pond.

4. The method of claim 1, wherein, The light strip is a waterproof LED light strip, and the wavelength of light emitted during operation is in a range that has an attractive effect on plankton; the light strip is laid along the length direction of the pond, and the distance between adjacent light strips is kept uniform.

5. The method of claim 1, wherein, The diameter of the first feeding pipe of the manual feeder is matched with the size of the micro cracks, so that the micro cracks are closed under low pressure and the feed is uniformly discharged under high pressure; the diameter of the second feeding pipe of the automatic feeder is matched with the size of the feeding holes, so that the granular feed can be uniformly distributed on the surface of the water body after being sprayed.

6. The method of claim 1, wherein, The liquid feed is a soybean milk type nutrient feed, and the feeding amount is adjusted according to the number of released large-eyed larvae; the granular feed is a microparticle feed suitable for the feeding of crab larvae, and the feeding amount is dynamically adjusted according to the growth stage and feeding condition of the crab larvae.

7. The method of claim 1, wherein, The large-eyed larvae are released at an appropriate release density, and the water salinity and water temperature during release are maintained within the range suitable for Chinese mitten crab large-eyed larvae.

8. The method of claim 1, wherein, The water quality indexes are monitored regularly during the cultivation process to keep the dissolved oxygen, pH value, ammonia nitrogen and nitrite content within the suitable range for the growth of the seedlings.

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