A high-efficiency and low-stress transport method for four-fingered threadfin fry via land and sea relay

Abstract

The present invention relates to the technical field of fish fry transportation, and more specifically, to a method for high-efficiency, low-stress land-sea relay transportation of four-fingered threadfin fry. The method includes transportation from a nursery pond to a fry collection pond, intelligent fry counting and underwater transportation, fry delivery to a fry transport box, land rail transportation to a transport vehicle, crane transfer to the transport vehicle, and then to a dock and offshore transportation, and final delivery from a transport ship to a net cage. During the transportation process, a buffer discharge pipe and an underwater transportation system are utilized, combined with an intelligent counting machine and an independent circulating water and liquid oxygen supply system of the fry transport box, so that the fry are always in a stable water environment, thus avoiding mechanical damage and reducing stress caused by environmental mutations. At the same time, all links operate efficiently and collaboratively, fundamentally solving the problem of high mortality caused by mechanical damage, environmental mutations, and stress reactions during the transportation process, thereby improving the survival rate of the fry and ensuring smooth aquaculture production.

Description

Technical Field

[0001] The invention relates to the technical field of fish fry transportation, in particular to a land-sea relay high-efficiency and low-stress transportation method for four-fingered threadfin fry. Background Art

[0002] The four-fingered threadfin flounder, commonly known as the threadfin flounder, is a euryhaline fish widely distributed in tropical and subtropical waters. Due to its rapid growth and delicious meat, it has become an important aquaculture species in my country's southern coastal areas. In recent years, breakthroughs in artificial breeding technology have enabled large-scale aquaculture of the four-fingered threadfin flounder. For example, the South China Sea Fisheries Research Institute of the Chinese Academy of Fishery Sciences successfully completed research on fully artificial propagation and seedling rearing technology for the four-fingered threadfin flounder in 2015, producing a large number of healthy fry.

[0003] However, four-fingered threadfin fry are extremely susceptible to stress during transportation, resulting in high mortality rates and severely restricting the development of the aquaculture industry. Existing transportation methods mainly rely on transporting them in oxygenated plastic bags, but this method has many drawbacks, such as the fry being susceptible to mechanical damage, difficulty maintaining dissolved oxygen levels, and difficulty controlling water temperature during transportation. All of these factors affect the survival rate of four-fingered threadfin fry. In addition, the fry may secrete large amounts of mucus due to stress during transportation, further exacerbating the mortality rate. To address these issues, the South China Sea Fisheries Research Institute has proposed a method for factory-based aquaculture of four-fingered threadfin fry, using artificially prepared seawater and a closed circulating water system. This method solves the environmental control problem during aquaculture to a certain extent, but there is still a lack of effective low-stress solutions for the transportation of fry, and it has failed to fundamentally address the high mortality rate of fry caused by mechanical damage, environmental mutations, and stress during transportation.

[0004] In view of this, there is an urgent need for an efficient and low-stress transport method for four-fingered threadfin fry from land to sea. Summary of the Invention

[0005] The object of the present invention is to provide a method for the efficient and low-stress land-sea relay transportation of four-fingered threadfin fry, which can effectively reduce the stress response of the fry during transportation, improve the survival rate, and ensure the smooth progress of aquaculture production, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides a method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry, comprising the following steps:

[0007] S1. Transfer from the nursery pond to the seedling collection pond: In the nursery pond of the factory nursery workshop with a length of 47m and a width of 17m, there are 20 nursery ponds with a length of 6m, a width of 3.5m and a depth of 1.5m. A passage with a width of 2m and a length of 47m is set in the middle of the 20 nursery ponds. Because the distance between the nursery pond and the seedling collection pond is only 50cm, the water level of the nursery pond needs to be lowered to 55cm-65cm, and the 6-inch plastic pipe inserted at the bottom of the nursery pond needs to be pulled open to discharge the fry smoothly through the preset sewage pipe and transport them to the seedling collection pond. A seedling collection pond is set up in the passage with 2 ponds on the left and 2 ponds on the right as a group. The fry flow into the seedling collection cage in the seedling collection pond (a switch is set at the bottom to control the flow rate) through the pipe mouth. The sewage pipe is provided with a buffer section and a flow rate control device to control the smoothness of the water flow, reduce the stress of the fry caused by the impact, and transfer the fry from the closed nursery environment to the more open seedling collection pond with minimal environmental changes.

[0008] S2. Intelligent fry counting and underwater transfer: Fry are collected from the fry collection cages using a closed water basin device with a sloped bottom, which keeps the fry in the water at all times, preventing stress from leaving the water. The collected fry are then smoothly and evenly introduced into an intelligent counting machine for automatic counting. The machine integrates a machine vision system with a 2000fps high-speed camera at the end of the guide tube. This machine utilizes image recognition technology and high-precision counting software to achieve dynamic counting with an error rate of less than 0.5%, accurately recording the number of fry in real time.

[0009] S3. Transporting fry to fry transport box: After being counted, the fry flow directly into the fry transport box through the conveying pipe. The specifications of the fry transport box are 1.25m long, 0.8m wide and 1m high. The outer layer (support layer) of the structure is made of carbon fiber reinforced resin (CFRP), the middle layer is made of bio-based closed-cell foam material, and the inner layer (water bag) is made of multi-layer composite high-strength flexible material. It is equipped with an independent circulating water system and liquid oxygen supply system, and integrates the central liquid oxygen supply system interface; the conveying pipe is equipped with a buffer diversion system, which consists of a flexible or rigid pipe with a smooth inner wall and a diameter of 10-20cm. At the same time, it is combined with an air source system composed of a low-pressure fan or air compressor with a pressure of <0.1MPa, a mixing chamber for mixing fry and water, a fish-water separation device at the conveying terminal, and a control unit with adjustable air flow speed and pulse frequency. In the mixing chamber, the fry and water form a suspension in a volume ratio of 3:1-5:1, and 0.1kg / m 3 -0.3kg / m 3A buffer is used to reduce friction between the fish bodies and between the fish bodies and the pipe wall. Subsequently, a low-pressure airflow generated by a low-pressure fan or air compressor is injected from the bottom or side of the conveying pipe at a speed of 6m / s-12m / s, creating a Venturi effect, driving the fish-water mixture to form a segmented plug flow (non-continuous full pipe flow). This ensures that the fry are always surrounded by the water medium and avoid direct friction with the pipe wall. The fish-water mixture is propelled in a pulsed manner at 2-4 pulses per second. At this time, the fry follow a spiral forward trajectory in the pipe, with an average conveying speed of 0.8m / s-1.2m / s. When the fish-water mixture enters the fish-water separation device, the fish and water are automatically separated by an inclined screen. The separated water flow can be recycled after filtration. The fry are continuously in a low-stress state during the conveying process, without being affected by severe bumps or sudden temperature changes.

[0010] S4. Transport to transport vehicle by land rail: The seedling transport box is equipped with an automatic identification tag and positioning system, which enables the seedling transport box to be accurately identified and positioned. Subsequently, the seedling transport box is transported by the rail transport system to the loading area of ​​the special transport vehicle for fry. The rail system is driven by automatic navigation and precise positioning modules, which enables the seedling transport box to move stably and accurately during the transportation process. Among them, the special transport vehicle for fry has two specifications, namely a 7m long 8-box vehicle and a 14m long 16-box vehicle. It has an automatic opening and closing function of the top cover to facilitate the loading and unloading of the seedling transport box. It is also equipped with an intelligent temperature control system to regulate the temperature inside the vehicle to meet the temperature requirements of the fry. It is also equipped with a central liquid oxygen supply system to continuously provide sufficient oxygen for the fry and provide a living environment. In addition, there is a video observation system to facilitate the observation of the status of the fry in the vehicle at any time.

[0011] S5. Transfer by crane to transport vehicle, then to the dock and sea: At the transport vehicle loading area, a crane equipped with a variable-speed intelligent control system is used to automatically lift the seedling transport box from the track onto the transport vehicle. The crane operates slowly and smoothly throughout the entire process to prevent sudden stops or rapid vibrations from causing stress to the fry. The loaded transport vehicle drives to the dock, and the dock crane is used to lift the seedling transport box directly onto the deck of the transport ship.

[0012] S6. Final placement from transport vessel to cages: After the transport vessel arrives at the modern marine ranch, the onboard crane is used to invert the fry in the fry transport cages and guide the fry into pre-arranged cages with a knotless screen structure with a mesh size of 5. The cages have water circulation and can effectively isolate external pollution to prevent the fry from escaping.

[0013] In the present invention, firstly, a buffer discharge pipe and an underwater conveying system are utilized to ensure that the fry have a continuous supply of water environment throughout the entire process from the nursery pond to the fry collection box, which not only effectively reduces the stress response of the fry caused by mechanical impact and water flow fluctuation, but also allows the fry to transition in a stable water environment and reduce the stimulation caused by environmental changes; at the same time, a special conveying pipe is used in combination with an automatic diversion and buffering system to safely convey the fry from the intelligent counting system to the fry collection box, such as the buffer diversion system in the conveying pipe, which realizes a stable conveying environment by controlling the flow rate change; it can also effectively improve the comfort of the fry during the entire conveying process, so that the temperature, flow rate and vibration factors of the environment in which the fry are located are maintained in the optimal state, further reducing the stress level of the fry and improving the survival rate of the fry.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The method is used for the efficient and low-stress land-sea relay transportation of four-fingered threadfin fry. By setting up a buffer diversion system and configuring intelligent equipment in each link of the transportation, the stress reaction of the fry is effectively reduced. During the transportation process, the buffer discharge pipe and the underwater transportation system are used, combined with the independent circulating water and liquid oxygen supply system of the intelligent counting machine and the fry transport box, not only the fry are always in a stable water environment to avoid mechanical damage, but also some environmental factors such as water quality, temperature and dissolved oxygen can be controlled to reduce stress caused by environmental mutations. At the same time, the fully automated track, crane and intelligent monitoring system realize the collection and regulation of real-time water quality, temperature, flow rate and vibration data. The efficient and coordinated operation of various links avoids the problems of difficult maintenance of dissolved oxygen content and difficult control of water temperature in traditional plastic bag oxygenation transportation, and fundamentally solves the problem of high mortality rate of fry caused by mechanical damage, environmental mutation and stress reaction during transportation, thereby improving the survival rate of fry and ensuring smooth breeding production.

[0016] 2. This method for the efficient and low-stress land-sea relay transportation of four-fingered threadfin fry adopts a full-process low-stress transportation process and a buffer diversion system structural design, which not only achieves seamless connection of all links from the nursery pond to the marine ranch and continuous and stable control of the water environment, but also keeps the fry in a low-stress state and reduces the damage to the fry caused by uneven stress caused by water flow impact and mechanical vibration; it also relies on the precise counting of the intelligent counting machine, as well as the independent circulating water and liquid oxygen supply system of the fry transport box and the intelligent temperature control, liquid oxygen supply, and video observation functions of the fry-specific transport vehicle to provide a stable and suitable living environment for the fry. At the same time, the buffer diversion channel and multi-section partition design inside the fry collection box regulate the flow rate, reducing the risk of vibration and collision of the fry during transportation, thereby improving the survival rate of the fry. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1The present invention is a flowchart of a method for efficiently and low-stressly transporting four-fingered threadfin fry by land and sea relay. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments 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 those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention. Example 1

[0019] In the nursery pond of the factory nursery workshop, which is 47m long and 17m wide, there are 20 nursery ponds, each 6m long, 3.5m wide and 1.5m deep. A passage 2m wide and 47m long is set in the middle of the 20 nursery ponds. The water level of the nursery pond is lowered to 60cm, and the 6-inch plastic pipe inserted in the bottom of the nursery pond is pulled open. The fry are discharged smoothly through the preset sewage pipe and transported to the seedling collection pond. A seedling collection pond is set up in the passage with two ponds on the left and two ponds on the right as a group. The fry flow into the seedling collection cage in the seedling collection pond (with a switch at the bottom to control the flow rate) through the pipe. The sewage pipe is equipped with a buffer section and a flow rate control device to control the smoothness of the water flow, reduce the stress on the fry caused by the impact, and enable the fry to be transferred from the closed nursery environment to the more open seedling collection pond with minimal environmental changes.

[0020] Afterwards, the fry in the fry collection cages are collected using a water basin device. The water basin device is a closed structure with a slanted bottom, which keeps the fry in the water at all times, avoiding stress reactions caused by being out of water. The collected fry are then smoothly and evenly introduced into an intelligent counting machine for automatic counting. The intelligent counting machine integrates a machine vision system with a 2000fps high-speed camera at the end of the guide tube. Utilizing image recognition technology and high-precision counting software, it achieves dynamic counting with an error rate of less than 0.5%, accurately recording the number of fry in real time.

[0021] Then, the counted fry are directly flowed into the fry transport box through the conveying pipe. The specifications of the fry transport box are 1.25m long, 0.8m wide and 1m high. The outer layer (support layer) of the structure is made of carbon fiber reinforced resin (CFRP), the middle layer is bio-based closed-cell foam material, and the inner layer (water bag) is a multi-layer composite high-strength flexible material. It is equipped with an independent circulating water system and liquid oxygen supply system, and an integrated central liquid oxygen supply system interface; the conveying pipe is equipped with a buffer diversion system. In the mixing chamber, the fry and water form a suspension in a volume ratio of 4:1, and 0.2kg / m³ of buffer is added to reduce the friction between the fish bodies and between the fish bodies and the pipe wall. Subsequently, the low-pressure fan or air compressor generates a low-pressure Air is injected from the bottom of the conveying pipe at a speed of 8m / s, creating a Venturi effect, which drives the fish-water mixture into a segmented plug flow (non-continuous full-pipe flow). This ensures that the fry are always surrounded by the water medium and avoid direct friction with the pipe wall. The fish-water mixture is propelled in a pulsed manner at 3 pulses per second. At this time, the fry follow a spiral trajectory in the pipe with an average conveying speed of 1m / s. When the fish-water mixture enters the fish-water separation device, the fish and water are automatically separated by an inclined screen. The separated water flow can be recycled after filtration. The fry are continuously in a low-stress state during the transportation process, without being affected by severe turbulence or sudden temperature changes. The fry transport box is equipped with an automatic identification tag and positioning system, which enables the fry transport box to be accurately identified and located.

[0022] Subsequently, the seedling transport box is transported by the rail transport system to the loading area of ​​the special transport vehicle for fry. The rail system is driven by automatic navigation and precise positioning modules, so that the seedling transport box can move stably and accurately during the transportation process; in the loading area of ​​the transport vehicle, a crane equipment equipped with a variable speed intelligent control system is used to automatically lift the seedling transport box from the rail to the transport vehicle. The crane operation process is slow and smooth throughout to prevent the fry from being stressed by sudden stops or rapid vibrations. The loaded transport vehicle drives to the dock, and the dock crane is used to lift the seedling transport box directly to the deck of the transport ship; after the transport ship drives to the modern marine ranch, the crane on the ship is used to invert the fry in the seedling transport box and guide it into the pre-arranged cage with a knotless screen structure with a mesh size of 5. Example 2

[0023] In the same factory nursery workshop as in Example 1, the water level of the nursery pond was lowered to 58 cm, a 6-inch plastic pipe inserted at the bottom of the nursery pond was pulled open, and the fry were discharged smoothly through the preset sewage pipe and transported to the seedling collection pond; the subsequent steps were the same as in Example 1, except that in the buffer diversion system of the transport pipe, the fry and water were suspended in a volume ratio of 3:1, and 0.1 kg / m 3 The buffer agent, the low-pressure air flow velocity is 6m / s, the pulse frequency of the fish-water mixture is 2 pulses per second, and the average conveying speed is 0.8m / s, which finally guides the fry into the cage. Example 3

[0024] In the nursery pond of the same factory nursery workshop as in Example 1, the water level of the nursery pond was lowered to 62 cm to discharge the fry and transport them to the fry collection pond; after the fry were intelligently counted and transported in water, when the fry were transported to the fry transport box, the fry and water were suspended in a buffer diversion system of the transport pipeline at a volume ratio of 5:1, and 0.3 kg / m 3 The buffer, low pressure air velocity is 12m / s, the pulse frequency of the fish-water mixture is 4 pulses per second, and the average conveying speed is 1.2m / s. The other steps are the same as those in Example 1, and the fry are finally introduced into the net cage.

[0025] Test example

[0026] The purpose of this experimental group is to explore the effects of different transport conditions on fry transport and to detect the efficiency, stability and survival rate improvement effects of the fry transport of the present invention.

[0027] Experimental objectives: Experimental group A, experimental group B and experimental group C respectively adopted the fry transport conditions provided in Example 1; the control example adopted control group A, control group B, control group C and control group D, wherein:

[0028] Control group A

[0029] In the nursery pond of the factory nursery workshop with a length of 47m and a width of 17m, there are 20 nursery ponds with a length of 6m, a width of 3.5m and a depth of 1.5m. A channel with a width of 2m and a length of 47m is set in the middle of the 20 nursery ponds; the water level of the nursery pond is lowered to 60cm, and the 6-inch plastic pipe inserted at the bottom of the nursery pond is pulled open to discharge the fry through the preset sewage pipe and transport it to the fry collection pond. However, the sewage pipe is not equipped with a buffer section and a flow rate control device, the water flow impact is large, and the fry are subjected to great stress during the transfer process; afterward, a water basin device is used to collect the fry in the fry collection cage, and the collected fry are introduced into an ordinary counting machine for counting. The counted fry flow into the fry transport box through an ordinary conveying pipe. The fry transport box does not have an independent circulating water system and liquid oxygen supply system, and only adopts simple oxygenation measures; afterward, the fry transport box is moved by a crane to the loading area of ​​the special fry transport vehicle. After the transport ship sails to the modern marine ranch, the fry are introduced into the cage.

[0030] Control group B

[0031] In the nursery pond of the factory nursery workshop, the transfer of fry from the nursery pond to the fry collection pond is carried out normally, and the intelligent counting of fry and the underwater transfer link are operated normally. In the step of transporting the fry to the fry transport box, the fry collection box is not provided with a buffer diversion channel and a multi-section partition design, which cannot effectively disperse and alleviate the uneven stress caused by the impact of water flow and mechanical vibration during the transportation process. Although there is a basic conveying structure in the conveying pipeline, the flow rate cannot be accurately controlled, and the fry are at high risk of vibration and collision during the transportation process. The subsequent handling and transportation of the fry transport box are the same as in Example 1.

[0032] Control group C

[0033] The traditional plastic bag oxygenation transport method is used. Four-finger threadfin fry are directly placed in plastic bags and filled with an appropriate amount of oxygen before transportation. During transportation, the fry are susceptible to mechanical damage, making it difficult to maintain dissolved oxygen levels. The water temperature is also difficult to control during transportation, and the fry secrete large amounts of mucus due to stress, leading to increased mortality. Furthermore, manual counting is used during the counting process, which is inefficient and prone to large errors. The fry are finally released into cages.

[0034] Control group D

[0035] A simple buffering device was installed during the transfer process from the nursery pond to the collection pond, but its effectiveness was limited. The intelligent counting of fry used low-precision counting equipment, resulting in large errors. When the fry were transported to the fry transport boxes, the buffering and diversion systems in the delivery pipelines were inadequate, failing to effectively control the flow rate and protect the fry. The fry transport boxes were equipped with simple aeration equipment, but this failed to provide a stable oxygen supply or control water quality. During transportation, ordinary vehicles were used, making it impossible to effectively control environmental factors such as temperature. Finally, the fry were released into the net cages.

[0036] Test conditions:

[0037] 1. Fry selection: Select healthy and disease-free four-fingered threadfin fry of similar size (approximately 5-8 cm in length). Each test group uses 1,000 fry.

[0038] 2. Environmental conditions: The experiment was conducted under the same environmental conditions such as weather, water temperature (25℃-28℃), salinity (28‰-32‰), and the same transportation distance (the distance from the nursery to the marine ranch was fixed).

[0039] 3. Equipment conditions: Except for the different transfer equipment and measures used in the experimental and control groups, other auxiliary equipment (such as cranes, dock facilities, etc.) remained consistent.

[0040] The calculation formula is as follows:

[0041] Fry survival rate: survival rate = (final number of surviving fry / initial number of fry) × 100%;

[0042] Fry damage rate: damage rate = (number of damaged fry / initial number of fry) × 100% (damage includes mechanical damage, physical abnormalities caused by stress, etc.);

[0043] Transfer efficiency: Transfer efficiency = total number of transferred fry / total transfer time (unit: fish / hour);

[0044] Experimental methods:

[0045] Data Collection: At each stage of fry transportation, including from the nursery pond to the collection pond, intelligent fry counting and underwater transfer, fry delivery to fry transport boxes, land rail transportation to transport vehicles, crane transfer to transport vehicles, and then to the dock and sea transportation, and final release from the transport ship to the cages, data such as the number of fry, condition (whether there are any injuries, stress response level, etc.), and transportation time are recorded.

[0046] Water quality monitoring: During the transportation process, the water quality (including dissolved oxygen content, pH value, water temperature, etc.) in the seedling transport box should be monitored and recorded every hour;

[0047] Stress response assessment: By observing the fry's behavioral performance (such as swimming status, whether they aggregate or disperse, whether they swim abnormally, etc.) and physiological indicators (such as mucus secretion and body color changes, etc.), the degree of stress response of the fry is assessed and divided into three levels: mild stress, moderate stress, and severe stress;

[0048] Repeated experiment: In order to ensure the reliability of the test results, each experimental group and control group were repeated three times, and the average value was taken as the final result.

[0049] Specific detection indicators are shown in Table 1.

[0050] Table 1 Test indicators of each sample

[0051] Test Example A Test Example B Test Example C Control group A Control group B Control group C Control group D Initial number of fry (tails) 1000 1000 1000 1000 1000 1000 1000 Final number of surviving fry (tails) 992 988 990 920 940 880 900 Survival rate (%) 99.2 98.8 99.0 92.0 94.0 88.0 90.0 Number of damaged fry (tails) 8 12 10 80 60 120 100 Damage rate (%) 0.8 1.2 1.0 8.0 6.0 12.0 10.0 Total transit time (h) 5 5.2 4.8 6 5.5 7 6.5 Transfer efficiency (tails / h) 200. 192.3 208.3 166.7 181.8 142.9 153.8 Average dissolved oxygen content (mg / L) 6.5 6.3 6.6 5.0 5.5 4.5 5.2 Average water temperature (℃) 26.5 26.2 26.8 26 26.3 25.5 26 Stress response degree (ratio) Mild stress: 90%, moderate stress: 10%, severe stress: 0% Mild stress: 88%, moderate stress: 12%, severe stress: 0% Mild stress: 92%, moderate stress: 8%, severe stress: 0% Mild stress: 60%, moderate stress: 30%, severe stress: 10% Mild stress: 70%, moderate stress: 25%, severe stress: 5% Mild stress: 40%, moderate stress: 40%, severe stress: 20% Mild stress: 50%, moderate stress: 35%, severe stress: 15%

[0052] According to Table 1, the comparison data are summarized as follows:

[0053] In terms of survival rate: the survival rates of the fry in the test groups A, B and C were 99.2%, 98.8% and 99.0% respectively, which were all at a high level. This was due to the buffer discharge pipe and underwater transportation system used in the transportation method of the present invention, which kept the fry in a stable water environment from the nursery pond to the fry collection box, reducing the stimulation caused by mechanical shock and environmental changes; the independent circulating water system and liquid oxygen supply system equipped in the fry transport box could control environmental factors such as water quality, temperature and dissolved oxygen, and avoid stress caused by sudden changes in the environment, thereby effectively improving the survival rate of the fry. The control group A had no buffer discharge pipe. The flushing section and flow rate control device resulted in a large water flow impact, and the seedling transport box was only simply oxygenated, with a survival rate of 92.0%; the control group B seedling collection box had no buffer diversion channel and multi-section partition design, and the conveying pipeline could not accurately control the flow rate, with a survival rate of 94.0%; the control group C used traditional plastic bags for oxygenation transportation, the fry were easily damaged by mechanical damage, and the dissolved oxygen content and water temperature were difficult to control, with a survival rate of only 88.0%; the control group D had imperfect equipment and measures in all links, with a survival rate of 90.0%; the lower survival rates of these control groups highlight the advantages of the transportation method of the present invention in maintaining the stability of the fry living environment.

[0054] In terms of damage rate: the damage rates of the experimental groups A, B, and C were 0.8%, 1.2%, and 1.0%, respectively, which were at a relatively low level; in the transfer method of the present invention, the buffer diversion system in the conveying pipeline reduces the friction between the fish bodies and between the fish bodies and the pipe wall by controlling the flow rate change, adding buffers, and forming segmented plug flows, thereby reducing the risk of damage to the fry; the buffer diversion channel and multi-segment partitioning design inside the fry collection box can also effectively disperse and alleviate the uneven stress caused by water flow impact and mechanical vibration during the transfer process, thereby reducing the damage rate; the damage rates of the control groups A, B, C, and D were 8.0%, 6.0%, 12.0%, and 10.0%, respectively, which were significantly higher than those of the experimental group; this shows that the transfer method of the present invention has a good effect in reducing mechanical damage to fry.

[0055] In terms of transport efficiency: the transport efficiency of the experimental groups A, B, and C were 200 tails / h, 192.3 tails / h, and 208.3 tails / h, respectively, which were relatively high; in the transport method of the present invention, the intelligent counting machine realized dynamic counting with an error rate of less than 0.5%, and recorded the number of fry in real time and accurately, thereby improving the counting efficiency; the fully automated track, crane, and intelligent monitoring system realized efficient coordinated operation of each link, shortened the total transport time, and thus improved the transport efficiency; the transport efficiency of the control groups A, B, C, and D were 166.7 tails / h, 181.8 tails / h, 142.9 tails / h, and 153.8 tails / h, respectively, which were lower than those of the experimental group.

[0056] In terms of dissolved oxygen content: the average dissolved oxygen content of the experimental groups A, B, and C were 6.5 mg / L, 6.3 mg / L, and 6.6 mg / L, respectively, which were maintained at a relatively high level. The independent circulating water system and liquid oxygen supply system equipped in the seedling transport box, as well as the integrated central liquid oxygen supply system interface, can continuously provide sufficient oxygen for the fry, ensuring the survival needs of the fry during transportation; the average dissolved oxygen content of the control groups A, B, C, and D were 5.0 mg / L, 5.5 mg / L, 4.5 mg / L, and 5.2 mg / L, respectively, which were lower than those of the experimental group, indicating that the transport method of the present invention has more advantages in dissolved oxygen control and can provide a more suitable living environment for the fry.

[0057] In terms of water temperature: the average water temperatures of the experimental groups A, B, and C were 26.5°C, 26.2°C, and 26.8°C, respectively, which were relatively stable and suitable for the survival of the fry. The intelligent temperature control system equipped in the special transport vehicle for fry can regulate the temperature in the vehicle, meet the temperature requirements of the fry, and reduce the stress response caused by temperature changes; the average water temperatures of the control groups A, B, C, and D were 26°C, 26.3°C, 25.5°C, and 26°C, respectively. Although there were certain fluctuations, the amplitude was relatively small. However, the water temperature of the control group C fluctuated greatly, affecting the living environment of the fry; this shows that the transport method of the present invention is more stable in water temperature control.

[0058] In terms of the degree of stress response: the stress response degree of the experimental groups A, B, and C was mainly mild stress, with proportions of 90%, 88%, and 92%, respectively. The proportion of moderate stress was relatively low, and there was no severe stress. The transport method of the present invention sets a buffer diversion system and configures intelligent equipment in each link, so that the fry are always in a stable water environment and a suitable living environment, reducing the stress response caused by environmental mutations and mechanical damage. Among the stress response degrees of the control groups A, B, C, and D, the proportions of moderate stress and severe stress were relatively high, and the proportion of severe stress in the control group C reached 20%, indicating that the transport method of the present invention has obvious effect in reducing the stress response of fry, and can effectively improve the life quality and survival rate of fry.

[0059] In summary, by setting up a buffer diversion system and configuring intelligent equipment in each link of transportation, such as buffer discharge pipes and underwater transportation systems, intelligent counting machines, seedling transport boxes equipped with independent circulating water and liquid oxygen supply systems, automated rails and cranes, and intelligent monitoring systems, seamless connection of all links from the nursery pond to the marine ranch and continuous and stable control of the water environment are achieved. This not only effectively reduces the stress response of the fry, reduces mechanical damage, and avoids stress caused by sudden environmental changes, but also controls environmental factors such as water quality, temperature, and dissolved oxygen. At the same time, the intelligent counting machine achieves efficient and accurate counting, and the efficient and coordinated operation of all links improves the transportation efficiency, fundamentally solving the problem of high mortality rate of fry caused by mechanical damage, sudden environmental changes and stress response during transportation, improving the survival rate and quality of life of the fry, and improving the transportation efficiency.

[0060] 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 high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry, characterized in that: The following steps are involved: S1. Transfer from nursery pond to collection pond: The factory nursery workshop is equipped with 20 nursery ponds with a central passage. First, adjust the water level in the nursery ponds, pull open the plastic pipes at the bottom of the ponds, and smoothly discharge the fry through the pre-set sewage pipes and transfer them to the collection ponds. The sewage pipes are equipped with buffer sections and flow rate control devices to control the smoothness of the water flow. S2. Intelligent fry counting and underwater transfer: A water basin device is used to collect fry from the fry collection cage. The collected fry are smoothly and evenly introduced into the intelligent counting machine for automatic counting, and the number of fry is recorded in real time and accurately. S3. Fry transport to the fry transport box: After being counted, the fry flow directly into the fry transport box through the delivery pipe. The buffer diversion system in the delivery pipe consists of a smooth pipe, a low-pressure air source system, a mixing chamber, a fish-water separation device, and a control unit. In the mixing chamber, the fry and water form a suspension, and a buffer is added to reduce friction between the fish and between the fish and the pipe wall. The low-pressure airflow drives the fry to form a segmented plug flow, and the fish and water are separated after pulse propulsion. S4. Transport to transport vehicle by land rail: The seedling transport box is equipped with an automatic identification tag and positioning system. The seedling transport box is transported by the rail transport system to the loading area of ​​the special transport vehicle for fry; S5. Transfer by crane to transport vehicle and then to the dock and sea transport: Use crane equipment equipped with a variable speed intelligent control system to lift the seedling box onto the transport vehicle. The loaded transport vehicle drives to the dock and then is lifted to the deck of the transport ship by the dock crane; S6. Final placement from the transport ship to the cages: After the transport ship arrives at the modern marine ranch, the ship's crane is used to invert the fry transport cages to guide the fry into the cages.

2. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In the S1, the specifications of the factory-type seedling nursery workshop are 47m long and 17m wide; the specifications of the 20 seedling pools are 6m long, 3.5m wide and 1.5m deep; the specifications of the passages are 2m wide and 47m long, and the passages are grouped into two seedling pools on the left and two seedling pools on the right to form a seedling collection pool.

3. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In S1, the water level in the nursery pond is lowered to 55 cm-65 cm.

4. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In S2, the water basin device is a closed structure, and the bottom is inclined.

5. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In the S2, the intelligent counting machine integrates a machine vision system with a 2000fps high-speed camera at the end of the guide tube, and uses image recognition technology and high-precision counting software to achieve dynamic counting with an error rate of less than 0.5%.

6. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In the S3, the specifications of the seedling transport box are 1.25m long, 0.8m wide and 1m high. The outer layer of its structure is made of carbon fiber reinforced resin, the middle layer is bio-based closed-cell foam material, and the inner layer is a multi-layer composite high-strength flexible material. It is equipped with an independent circulating water system and liquid oxygen supply system, and integrates a central liquid oxygen supply system interface.

7. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In the S3, the fry and water are suspended in a volume ratio of 3:1-5:1, and the amount of the buffer added is 0.1 kg / m 3 -0.3kg / m 3 .

8. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In the above-mentioned S3, the pulse propulsion is carried out at 2-4 pulses per second. At this time, the fry advances in a spiral trajectory in the conveying pipe, and the average conveying speed is 0.8m / s-1.2m / s.

9. The method for high-efficiency and low-stress land-sea relay transport of four-fingered threadfin fry according to claim 1, characterized in that: In the S4, there are two specifications of the special transport vehicle for fry, namely, a 7m long 8-box vehicle and a 14m long 16-box vehicle. The special transport vehicle for fry has an automatic opening and closing function of the top cover, and is equipped with temperature control, liquid oxygen supply and video observation system.

10. The method for high-efficiency and low-stress land-sea relay transportation of four-fingered threadfin fry according to claim 1, characterized in that: In the above-mentioned S6, the net cage adopts a knotless screen structure with a mesh size of 5 meshes, and the net cage has a water circulation function.

Images