A land-sea relay farming method for yellowfin seabream

Abstract

This invention discloses a land-sea relay culture method for yellowfin seabream, belonging to the field of aquaculture technology. The method includes: cultivating yellowfin seabream fry in a land-based pond; when the fry reach a body length of 3.5–5.0 cm or a weight of 4–6 g, transferring them via land-sea relay; before transfer, subjecting the fry to salinity buffering acclimatization treatment by gradually increasing the salinity of the culture water to allow the fry to adapt to the seawater environment; during transportation, adjusting the temperature of the transport water to be 2–3°C lower than the temperature of the culture water in the land-based pond, and adding a compound nutritional anti-stress agent to the transport water; subsequently, releasing the fry into sea cages for further culture. Through the synergistic effect of salinity buffering acclimatization treatment, micro-cooling transportation, and nutritional anti-stress regulation, the physiological stress response of yellowfin seabream fry during land-sea relay transport can be effectively reduced, improving the survival rate of the fry during transport and enhancing subsequent culture results.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, specifically relating to a land-sea relay aquaculture method for yellowfin seabream, and more particularly to an aquaculture method that combines salinity buffering adaptation with micro-cooling transportation to reduce stress response during fish fry transfer. Technical Background

[0002] Yellowfin spiny seabream (Acanthopagrus latus), commonly known as yellow-footed seabream, is one of the important economic fish species widely distributed in the coastal and estuarine waters of southern my country. This fish is characterized by its strong adaptability, rapid growth rate, and excellent meat quality, making it highly valuable for aquaculture and in high market demand in the coastal areas of South China.

[0003] Currently, yellowfin seabream farming mainly employs two methods: land-based pond culture and offshore cage culture. Land-based culture offers advantages such as convenient management and controllable environment during the seedling stage, but it is prone to problems such as high pressure for water quality control and high culture costs in the later stages of culture. Offshore cage culture, on the other hand, has the advantages of sufficient water exchange and large culture capacity. However, if small-sized fry are directly released into offshore cages, the differences in temperature, salinity, and hydrodynamic conditions between the marine and land-based environments can cause strong stress responses in the fry, leading to a higher early mortality rate.

[0004] To combine the advantages of land-based aquaculture and offshore cage aquaculture, a land-sea relay aquaculture model has gradually emerged in recent years. This model involves raising fish fry to a certain size in land-based facilities and then transferring them to offshore cages for further cultivation. However, during the transition from land-based to marine environments, fish fry often experience rapid changes in salinity, temperature, and water conditions, which can easily lead to significant physiological stress responses, thereby affecting the survival rate of the fry during transport and their subsequent growth performance.

[0005] In existing technologies, measures to reduce stress during fish transport mainly include the use of chemical anesthetics (such as MS-222) or the adoption of complex transport buffering equipment. However, these methods not only increase aquaculture costs and involve cumbersome procedures, but also pose a risk of drug residues for some chemical agents, thus limiting their widespread application in general aquaculture production.

[0006] Therefore, developing a simple, low-cost, and effective land-sea relay farming method for yellowfin seabream that can reduce stress during fry transfer is of great significance for improving the survival rate of fry during transfer and promoting the large-scale farming of this species. Summary of the Invention

[0007] The purpose of this invention is to provide a land-sea relay aquaculture method for yellowfin seabream.

[0008] The method of this invention determines the most suitable fish fry transfer size, sets up a salinity buffer adaptation treatment before fish fry transfer, and combines micro-cooling transportation regulation and compound nutritional anti-stress regulation measures to mitigate the impact of environmental changes during the transition of fish fry from land-based aquaculture environment to marine aquaculture environment, thereby reducing the physiological stress response during fish fry transfer and improving the survival rate of fish fry and the stability of subsequent aquaculture.

[0009] The above-mentioned objective of the present invention can be achieved by the following technical solution: a land-sea relay aquaculture method for yellowfin seabream, comprising the following steps:

[0010] (1) Cultivating yellowfin seabream fry in land-based ponds;

[0011] (2) When the fish fry reach a body length of 3.5-5.0 cm or a weight of 4-6 g, they should be transferred.

[0012] (3) Before the fish fry are transported, a salinity buffering adaptation treatment is carried out. The salinity buffering adaptation treatment is to adjust the salinity of the aquaculture water in stages. The staged adjustment of the aquaculture water salinity includes: adjusting the aquaculture water salinity to 25‰~27‰ in the first stage, adjusting the aquaculture water salinity to 27‰~29‰ in the second stage, and adjusting the aquaculture water salinity to 29‰~31‰ in the third stage. Each stage lasts for 6~12 hours. (4) During the transportation process, a micro-cooling control is adopted, and a compound nutritional anti-stress agent is added to the transportation water for transportation. The micro-cooling control is to reduce the temperature of the transportation water by 2~3℃ compared with the temperature of the land-based pond cultivation water. (5) The transported fish fry are placed in marine net cages for cultivation.

[0013] In the above-mentioned land-sea relay farming method for yellowfin seabream:

[0014] Preferably, in step (1), when cultivating yellowfin seabream fry in a land-based pond, routine water quality management is carried out on the culture water to ensure the normal growth and development of the fry.

[0015] Preferably, in step (1), when cultivating yellowfin seabream fry in a land-based pond, the conditions of the culture water are: pH 7.5-8.5, salinity 20‰-26‰, dissolved oxygen 5-8 mg / L, and ammonia nitrogen ≤0.2 mg / L.

[0016] Preferably, in step (3), before the fish fry are transferred, the fish fry are subjected to salinity buffering adaptation treatment. By gradually supplementing the aquaculture water with seawater, the salinity of the aquaculture water is gradually increased to be close to the salinity of the sea area where the net cage aquaculture is conducted, so that the fish fry can gradually adapt to the seawater environment.

[0017] Preferably, the salinity buffering adaptation treatment in step (3) can be carried out in a separate acclimatization tank.

[0018] By adjusting the salinity in stages as described above, the fish fry can gradually adapt to the marine environment, which can reduce the osmotic stress response caused by sudden changes in salinity.

[0019] Preferably, the temperature of the transport water in step (4) is 21-22°C.

[0020] In step (4), the temperature of the transport water is gradually adjusted to be 2-3°C lower than that of the land-based pond culture water during the transportation process, which can reduce the metabolic level of the fish and reduce the stress response during transportation.

[0021] Preferably, adding compound nutritional anti-stress agent to the transport water in step (4) can maintain the physiological stability of fish fry during transportation.

[0022] Preferably, the compound nutritional anti-stress agent in step (4) includes vitamin C, taurine and glucose.

[0023] More preferably, the mass percentage of each component in the compound nutritional anti-stress agent is as follows: vitamin C 20%–50%, taurine 3%–15%, glucose 10%–40%, and the remainder is water or a water-soluble carrier, such as deionized water, physiological saline or other water-soluble solvents.

[0024] Preferably, the concentration of the compound nutritional anti-stress agent added to the transport water is 5-10 g / m³.

[0025] Preferably, in step (4), oxygen is continuously supplied during transportation to maintain the dissolved oxygen in the transport water at 5-9 mg / L.

[0026] Preferably, the marine environmental conditions for releasing the transferred fish fry into the marine cages for aquaculture in step (5) are: water temperature 22-28℃, salinity 25‰-35‰, and dissolved oxygen 5-9mg / L.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) Optimize the specifications for land-sea relay transportation

[0029] This invention clearly defines the suitable size for land-sea relay transport: a body length of 3.5–5.0 cm or a weight of 4–6 g. Studies have found that when the fry are less than 3.5 cm in length, their osmotic pressure regulation capacity is not yet fully developed, and direct entry into the seawater environment can easily cause a strong stress response. On the other hand, if the fry are longer than 5.0 cm, continuing to raise them in land-based ponds will increase the stocking density and water quality management pressure. Therefore, this invention selects a body length of 3.5–5.0 cm or a weight of 4–6 g as the suitable size for land-sea relay transport.

[0030] (2) Reduce environmental stress caused by sudden changes

[0031] By setting up a salinity buffer adaptation treatment (the first stage adjusts the salinity of the culture water to 25‰-27‰, the second stage adjusts it to 27‰-29‰, and the third stage adjusts it to 29‰-31‰, with each stage lasting 6-12 hours), the fish fry gradually adapt to the seawater environment before transfer, thereby reducing the osmotic stress response caused by the salinity difference between the land-based culture environment and the marine environment.

[0032] (3) Reduce metabolic load during transportation

[0033] Using a slightly cooled transport method (2-3°C lower than the water temperature in land-based ponds) can moderately reduce the metabolic level of fish and decrease energy consumption during transport, thereby improving the physiological stability of fish fry during transport.

[0034] (4) Synergistic anti-stress effect of multiple components

[0035] In the compound nutritional anti-stress agent: Vitamin C is used to improve the antioxidant capacity of fish; taurine is used to maintain the osmotic pressure balance of cells; glucose is used to provide energy for fish; the synergistic effect of multiple regulatory measures can reduce the physiological stress response during the transfer of fish fry and improve the survival rate of the transferred fish.

[0036] (5) Form a synergistic system of environmental regulation and nutritional regulation

[0037] The synergistic effect of salinity buffering adaptation treatment, micro-cooling transportation, and nutritional stress-relief measures can improve the environmental adaptability of yellowfin seabream fry during land-sea relay transportation, thereby increasing the success rate of fry transportation and the stability of subsequent aquaculture. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the land-sea relay aquaculture method for yellowfin seabream provided in Embodiments 1-2 of the present invention. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments. Various equivalent substitutions or modifications made by those skilled in the art without departing from the technical concept of the present invention should fall within the scope of protection of the present invention.

[0040] Example 1

[0041] The land-sea relay aquaculture method for yellowfin seabream provided in this embodiment is as follows: Figure 1As shown, the process includes: cultivating fish fry in land-based ponds, determining the specifications for land-sea relay transport, salinity buffering adaptation treatment, micro-cooling control of the transport water, stress resistance regulation of the transport water, and release into offshore net cage culture. During transport, a compound nutritional stress-relief agent is added to the transport water to maintain the physiological stability of the fish fry. This compound nutritional stress-relief agent includes nutrients such as vitamin C, taurine, and glucose. The specific steps are as follows:

[0042] (1) Yellowfin seabream fry were raised in land-based ponds in the coastal aquaculture areas of Guangdong.

[0043] Before stocking the seedlings, the pond is dredged, dried, and disinfected with quicklime. Then, water is added and the water is cultivated. Before stocking the seedlings, a compound microecological agent is sprinkled into the pond water to regulate the microecological environment of the water.

[0044] Yellowfin seabream fry were released into the aforementioned ponds for cultivation. During the cultivation process, the aquatic environment was kept stable through appropriate water exchanges and microecological regulation, maintaining the following water conditions: pH value approximately 8.0, salinity approximately 24‰, dissolved oxygen 5 mg / L, and ammonia nitrogen ≤0.2 mg / L. The fry were fed formulated feed twice daily during the cultivation period.

[0045] (2) During the breeding process, the size of the fish fry is measured regularly by sampling. When the average body length of the fish fry is about 4.8cm and the average weight is about 4.3g, the land and sea relay transportation is carried out.

[0046] (3) Before the transfer, the fish fry were subjected to salinity buffering adaptation treatment. Seawater was gradually added to the aquaculture water to increase the salinity of the aquaculture water in stages: the first stage was to adjust the salinity to about 26‰; the second stage was to adjust the salinity to about 28‰; and the third stage was to adjust the salinity to about 30-31‰.

[0047] Each salinity acclimatization phase lasts 12 hours. Through this phased salinity adjustment, the fish fry gradually adapt to the marine environment before being transferred.

[0048] (4) During transportation, ice blocks or seawater are added to the transport water to slowly reduce the temperature of the transport water from the original pond water temperature of about 24°C to about 21-22°C.

[0049] At the same time, a compound nutritional anti-stress agent is added to the transport water. The compound nutritional anti-stress agent contains approximately 35% vitamin C, approximately 10% taurine, approximately 20% glucose, and the remainder is water. The concentration used is 8g / m³.

[0050] During transportation, oxygen is continuously supplied to maintain the dissolved oxygen in the transport water at 5~9 mg / L.

[0051] (5) After about 3 hours of transportation, the fish fry arrive at the nearshore sea cages and are slowly released into the cages for aquaculture. The marine environment conditions for aquaculture are: water temperature 22-28℃, salinity 25‰-35‰, and dissolved oxygen ≥5 mg / L.

[0052] During the cage culture stage, compound feed or chilled feed is used for feeding, with a daily feeding amount of about 4% of the fish's body weight.

[0053] The results show that:

[0054] In this embodiment, approximately 10,000 yellowfin seabream fry were selected for a land-sea relay transport experiment. The number of fry was determined by randomly selecting a portion of the fry, measuring their average weight, and weighing the total weight of the fry. The average weight was converted to the total weight, and the same applies below. After the transport was completed, the fry were counted. 9,850 fry survived, and 150 died, resulting in a survival rate of 98.5% at the end of the transport.

[0055] The surviving fry were then released into sea cages for further aquaculture. 24 hours after being placed in the cages, the number of surviving fry was counted again, with 9,700 fry surviving and 300 dead, resulting in a survival rate of 97.0%.

[0056] Continued aquaculture observation: After 7 days of rearing in net cages, another count was conducted, and 9,520 fry survived while 480 died, resulting in a survival rate of 95.2%.

[0057] The results show that the method of the present invention can effectively improve the survival rate of yellowfin seabream fry during the land-sea relay transportation process.

[0058] Example 2

[0059] Unlike Example 1:

[0060] In step (2), when the average weight of the fish fry is about 5.8g, the land-sea relay transfer is carried out.

[0061] In step (3), before the fish fry are transferred, the fish fry are subjected to salinity buffering adaptation treatment. By gradually supplementing the aquaculture water with seawater, the salinity of the aquaculture water is increased in stages: the first stage is adjusted to about 26‰; the second stage is adjusted to about 28‰; and the third stage is adjusted to about 30-31‰.

[0062] Each salinity acclimatization phase lasts 6 hours. The fish fry are transferred only after the salinity buffering acclimatization is complete.

[0063] In step (4), the transport water is then gradually cooled down so that the temperature of the transport water is reduced by about 3°C, or 21°C, compared with the original aquaculture water.

[0064] In step (4), a compound nutritional anti-stress agent containing 30% vitamin C, 8% taurine, 25% glucose, and the remainder is water is added to the transport water. The concentration used is about 6g / m³.

[0065] After about 5 hours of transportation, the fish fry were released into offshore net cages for aquaculture. The management method for net cage aquaculture was basically the same as in Example 1.

[0066] The observation results show that:

[0067] Fish fry experience less stress after being released into the sea and recover their activity level more quickly.

[0068] Statistical results show:

[0069] In this embodiment, approximately 10,000 yellowfin seabream fry were selected for a land-sea relay transport experiment. After the transport was completed, statistics were performed, and 9,720 fry survived while 280 died, resulting in a survival rate of 97.2% at the end of the transport.

[0070] The surviving fry were then released into sea cages for further aquaculture. After 24 hours of rearing in the cages, a count was conducted, revealing 9,650 surviving fry and 350 dead fry, resulting in a survival rate of 96.5%.

[0071] Seven days after being placed in the net cages for rearing, a second count was conducted, revealing that 9,460 fry survived and 540 died, resulting in a survival rate of 94.6%.

[0072] This indicates that good aquaculture results can still be achieved by carrying out land-sea relay transportation under the above parameter conditions.

[0073] Comparative Example 1: Conventional Transportation Method

[0074] The fish fry cultivation process in step (1) is basically the same as in Example 1.

[0075] In step (2), the fish fry are transferred when their average weight is about 4.3g.

[0076] No salinity buffering adaptation was performed in step (3).

[0077] In step (4), the seawater at room temperature (about 24°C) was directly loaded and transported during the transfer process. The temperature of the transport water was not adjusted, and no anti-stress agent was added to the transport water.

[0078] In step (5), the fish fry are transported for about 3 hours and then released into the marine cages for aquaculture.

[0079] The statistical results at the end of the transportation showed that approximately 10,000 yellowfin seabream fry were selected for the transportation experiment in this comparative study. After the transportation, 8,660 fry survived and 1,340 died, with a survival rate of 86.6% at the end of the transportation.

[0080] The surviving fry were then released into net cages at sea for further rearing. Some fish exhibited obvious stress responses, such as slow swimming and reduced feeding. A follow-up count 24 hours after release showed that 8040 fry survived, while 1960 died, resulting in a survival rate of 80.4%.

[0081] Further observation revealed that on the 7th day after the fish were placed in the net cages, 7,450 fry survived and 2,550 died, resulting in a survival rate of 74.5%.

[0082] This indicates that without salinity buffering, cooling during transport, and anti-stress treatment, fish fry are prone to strong stress reactions during transportation, and the survival rate during transportation is significantly lower than that in Example 1.

[0083] Comparative Example 2: Postponing marine aquaculture

[0084] The process of raising fish fry is basically the same as in Example 1.

[0085] However, in step (2), the land-sea relay transfer was not carried out when the fish fry weighed about 4-6g. Instead, they continued to be raised in the land-based pond until the average weight of the fish was about 15g before being transferred.

[0086] In the later stages of land-based aquaculture, as the fish size increases and the biomass of the cultured fish continues to increase, the pond culture density rises significantly, increasing the pressure on water management.

[0087] Monitoring results show that:

[0088] During the land-based aquaculture stage, the ammonia nitrogen concentration repeatedly rose to above 0.25 mg / L.

[0089] Statistical results show:

[0090] Approximately 10,000 fish fry were released into the land-based pond rearing stage. When the fry were counted at the stage where the average weight was about 15g, 6,850 fish fry survived and 3,150 fish died, resulting in a survival rate of 68.5%.

[0091] Meanwhile, some fish fry exhibited a certain degree of stress response during subsequent transportation, such as decreased swimming ability, dispersal of fish groups, and reduced feeding.

[0092] After 24 hours of transporting and releasing the fish into marine cages for aquaculture, approximately 6,000 fry survived, representing a survival rate of about 60.0% relative to the initial stocking quantity.

[0093] This indicates that delaying the transfer not only increases the pressure on land-based aquaculture, but may also reduce the overall survival rate of aquaculture.

[0094] Comparative Example 3: No salinity buffering adaptation performed

[0095] The process of raising fish fry is basically the same as in Example 1.

[0096] In step (2), when the fish fry have an average body length of about 4.6 cm and an average weight of about 4.2 g, they are transported by land and sea in a relay.

[0097] However, in step (3), no salinity buffering adaptation treatment was carried out. Instead, the fish fry were directly caught from the land-based pond and then transported.

[0098] The transportation conditions in step (4) are basically the same as in Example 1. That is, during the transportation process, ice or cooling seawater is added to the transport water to reduce the temperature of the transport water by about 2-3°C compared with the original aquaculture water temperature. At the same time, a compound nutritional anti-stress agent is added to the transport water. The compound nutritional anti-stress agent contains about 35% vitamin C, about 10% taurine, about 20% glucose, and the remainder is water. The concentration used is about 8g / m³. Oxygen is continuously supplied during the transportation process to maintain the dissolved oxygen in the transport water above 5mg / L.

[0099] In step (5), the fish fry are transported for about 3 hours and then released into the nearshore sea cages for aquaculture. The environmental conditions of the aquaculture area are basically the same as those in Example 1.

[0100] The statistical results after the transportation was completed showed:

[0101] In this comparative experiment, approximately 10,000 yellowfin seabream fry were selected for a land-sea relay transport test. After the transport, approximately 9,120 fry survived and 880 died, with a survival rate of approximately 91.2% at the end of the transport.

[0102] The surviving fry were then released into sea cages for further aquaculture. After 24 hours of rearing in the cages, the number of fry was counted again, with approximately 8,880 surviving and 1,120 dead, resulting in a survival rate of approximately 88.8%.

[0103] Continued aquaculture observation showed that on the 7th day after being placed in the net cages, approximately 8,620 fry survived, while 1,380 died, resulting in a survival rate of approximately 86.2%.

[0104] The observation results show that, without salinity buffering adaptation treatment, fish fry are prone to strong osmotic stress when directly transferred from a land-based low-salinity aquaculture environment to a seawater environment. This manifests as unstable swimming, decreased activity in a short period of time, and slow recovery from feeding in a short period of time. Their survival rate after transfer and placement in net cages is lower than that in Example 1.

[0105] This indicates that by setting up a salinity buffer adaptation treatment during the land-sea relay aquaculture process, the fish fry can gradually adapt to the seawater environment before transfer, which helps to reduce the physiological stress response caused by sudden environmental changes, thereby improving the survival rate of fish fry during transfer and the stability of subsequent aquaculture.

[0106] The survival rate data in the above embodiments and comparative examples are all derived from the average of statistical results from no fewer than three batches of independent trials.

[0107] Summarize

[0108] The comparison results between Examples 1-2 and Comparative Examples 1-3 show that:

[0109] When the fish fry reach a size of 3.5–5.0 cm or 4–6 g, a land-sea relay transfer is performed. Through salinity buffering adaptation treatment, micro-cooling control during transportation, and regulation with compound nutritional anti-stress agents, the stress level of the fish fry during environmental transition can be effectively reduced, thereby improving the survival rate of the fry during transportation and enhancing subsequent aquaculture results. This invention's method is simple to operate, requires no chemical anesthetics or complex transportation equipment, and is suitable for widespread application in coastal aquaculture production.

[0110] The above embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Equivalent substitutions or modifications made by those skilled in the art without departing from the concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. A land-sea relay aquaculture method for yellowfin seabream, characterized in that, Includes the following steps: (1) Cultivating yellowfin seabream fry in land-based ponds; (2) When the fish fry reach a body length of 3.5-5.0 cm or a weight of 4-6 g, they should be transferred. (3) Before the fish fry are transported, a salinity buffering adaptation treatment is carried out. The salinity buffering adaptation treatment is to adjust the salinity of the aquaculture water in stages. The staged adjustment of the aquaculture water salinity includes: adjusting the aquaculture water salinity to 25‰~27‰ in the first stage, adjusting the aquaculture water salinity to 27‰~29‰ in the second stage, and adjusting the aquaculture water salinity to 29‰~31‰ in the third stage. Each stage lasts for 6~12 hours. (4) During the transportation process, a micro-cooling control is adopted, and a compound nutritional anti-stress agent is added to the transportation water for transportation. The micro-cooling control is to reduce the temperature of the transportation water by 2~3℃ compared with the temperature of the land-based pond cultivation water. (5) The transported fish fry are placed in marine net cages for cultivation.

2. The land-sea relay aquaculture method for yellowfin seabream according to claim 1, characterized in that, When cultivating yellowfin seabream fry in a land-based pond in step (1), the conditions of the culture water are: pH 7.5-8.5, salinity 20‰-26‰, dissolved oxygen 5-8 mg / L, and ammonia nitrogen ≤0.2 mg / L.

3. The land-sea relay aquaculture method for yellowfin seabream according to claim 1, characterized in that, The temperature of the transport water in step (4) is 21-22℃.

4. The land-sea relay aquaculture method for yellowfin seabream according to claim 1, characterized in that, The compound nutritional anti-stress agent mentioned in step (3) includes vitamin C, taurine and glucose.

5. The land-sea relay aquaculture method for yellowfin seabream according to claim 4, characterized in that, The mass percentage of each component in the compound nutritional anti-stress agent is as follows: Vitamin C 20%–50%, taurine 3%–15%, glucose 10%–40%, and the remainder is water or a water-soluble carrier.

6. The land-sea relay aquaculture method for yellowfin seabream according to claim 5, characterized in that, The concentration of the compound nutritional anti-stress agent added to the transport water is 5-10 g / m³.

7. The land-sea relay aquaculture method for yellowfin seabream according to claim 4, characterized in that, In step (4), oxygen is continuously supplied during transportation to maintain the dissolved oxygen in the transport water at 5~9 mg / L.

8. The land-sea relay aquaculture method for yellowfin seabream according to claim 1, characterized in that, In step (5), the marine environmental conditions for releasing the transferred fish fry into the marine cages for aquaculture are: water temperature 22-28℃, salinity 25‰-35‰, and dissolved oxygen 5-9mg / L.

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