Seasonal efficient cultivation method for large-scale oncorhynchus mykiss in northern natural sea area

Abstract

The invention discloses a seasonal efficient cultivation method for large-scale oncorhynchus mykiss in northern natural sea areas, and relates to the technical field of seasonal cultivation of oncorhynchus mykiss, in particular to a seasonal efficient cultivation method for large-scale oncorhynchus mykiss in northern natural sea areas, which comprises the following steps: A, a cultivation stage including a domestication stage and a cultivation stage; wherein the domestication stage comprises salinity adaptability domestication and ocean current adaptability domestication; based on the difference between a sea area and a land-based fresh water environment, large-size rainbow trout fries are subjected to salinity and ocean current dual-adaptability domestication before sea descending in advance, so that the rainbow trout fries can adapt to the growth environment of seawater with certain salinity in advance, and the rainbow trout fries can adapt to the ocean current environment in advance; the stress of the rainbow trout in the transportation process and after transportation can be effectively reduced, the physical function recovery time of the rainbow trout after sea descending is shortened, and the survival rate and growth rate of the rainbow trout after sea descending are improved.

Description

Technical Field

[0001] The invention relates to the technical field of seasonal rainbow trout breeding, and in particular to a seasonal and efficient breeding method for large-sized rainbow trout in northern natural seas. Background Art

[0002] Rainbow trout is a euryhaline cold-water fish that can live in fresh water for life, or it can transition from fresh water to seawater. The highest tolerable water temperature is 22-23°C, with no obvious lower temperature limit, and the most suitable living water temperature is 15-18°C. At present, domestic rainbow trout farming is mainly concentrated in inland cold water areas with rich freshwater resources, and it is a lifelong freshwater farming. The main farming modes include freshwater cage farming, pond series flow farming, factory flow farming and factory circulating water farming. For example, in the Chinese patent application with the publication number CN107950442B and the patent name of the salmon trout farming feeding method, the prior art is to use two sets of closed circulating water farming systems for salmon trout farming. As a kind of salmonid fish, rainbow trout belongs to the category of salmon trout. Although the prior art can carry out rainbow trout farming through the factory circulating water farming method, the prior art uses a large amount of freshwater resources in the farming process, and the farming scale is small, and the yield is low.

[0003] In the Chinese patent application with publication number CN110432188B and patent name A method for acclimating rainbow trout to seawater, the prior art method for acclimating rainbow trout to seawater uses artificial light supplementation to extend the light before entering the sea, so that large-sized fish species cultured in freshwater are physiologically transformed to salt tolerance, and then a two-step transition method of salinity is used for seawater acclimation. This method has the advantages of less harm to farmed fish and simple operation, and is an urgently needed technology for the development of seawater aquaculture to the deep sea. However, this prior art has certain limitations. This prior art does not acclimate rainbow trout to adapt to the sea current. Rainbow trout species live in existing land-based aquaculture facilities (such as freshwater cages, etc.) for a long time, and the water body is in a static or slightly flowing state. There is a huge difference between the water flow velocity and the ocean water flow velocity. The rainbow trout species are easily killed and injured by the ocean water flow velocity when they are released into the sea. Therefore, the rainbow trout species should be acclimated to the sea current before they are released into the sea.

[0004] With the rapid development of deep-sea aquaculture, rainbow trout has been listed as one of the main fish species for temperate coastal and deep-sea aquaculture in my country due to its nutritional value, industrial resources, market value and marine aquaculture advantages. However, since the summer water temperature in my country's temperate waters (such as the Yellow Sea and Bohai Sea) usually exceeds the tolerance of rainbow trout, it is impossible to carry out year-round aquaculture. It is necessary to establish a seasonal and efficient method for large-scale rainbow trout in natural waters in the north to meet the needs of rapid staged aquaculture of rainbow trout. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the deficiencies of the prior art, the present invention provides a seasonal and efficient method for growing large-sized rainbow trout in natural waters of northern China, which solves the problems raised in the above-mentioned background technology.

[0006] (II) Technical solution To achieve the above objectives, the present invention is implemented by the following technical solutions: a seasonal and efficient cultivation method for large-sized rainbow trout in northern natural waters, the method comprising the following contents: A. Cultivation stage: including domestication stage and cultivation stage; wherein the domestication stage includes salinity adaptation domestication and ocean current adaptation domestication; B. Breeding facilities: Land-based breeding facilities are used for breeding facilities in the domestication stage; cages are used for breeding facilities in the grow-out stage. The aquaculture water volume in a single breeding facility in the grow-out stage is ≥1000m³, and the water depth of the sea area where the breeding facility is located is ≥15m; C. Salinity adaptation: transfer freshwater rainbow trout fry to a water environment with an initial salinity of 5PSU, and increase the salinity gradient by 5PSU every 24 hours until the salinity reaches 30PSU; during the salinity adaptation process, the water temperature is maintained at 12℃~18℃, and the dissolved oxygen in the water is ≥8mg / L. The completion of salinity adaptation is marked by the restoration of normal clustering and feeding of rainbow trout fry; D. Sea current adaptation: Use land-based adaptation facilities to simulate the sea current environment and conduct sea current adaptation; E. Basic environmental requirements for the sea area during the culture stage: Choose natural sea areas near the coast or deep sea. The water temperature of the natural sea area should be 0℃~20℃ for a period of not less than 7 months. The dissolved oxygen in the water should be ≥6mg / L, the salinity should be 28PSU~32PSU, the flow rate should be <1.5m / s, and the light intensity of the natural sea area should be 400Lux~500Lux. F. Stocking at low sea level: Stocking is carried out when the surface water temperature in the natural sea area drops to 18°C ​​or below throughout the day, and the temperature difference between the target aquaculture sea area and the water environment of the land-based acclimation facility is ≤2°C, and the salinity difference is ≤3PSU; G. Stocking density in the grow-out stage: the stocking specification is 1.0kg to 1.5kg, the initial stocking density is 3kg / m³ to 5kg / m³; the maximum stocking density is 12kg / m³ to 15kg / m³; H. Feeding method in the growing stage: artificial compound feed is used throughout the whole feeding process, with crude protein content ≥45%, crude fat content ≥20%, and astaxanthin content of 40mg / kg; 3 months before listing, the crude fat content in the feed is increased to more than 25%, and the astaxanthin content in the feed is increased to 80mg / kg; I. Harvesting: Rainbow trout should be harvested before the surface water temperature in the sea area rises to 22℃ throughout the day.

[0007] Optionally, in the process of simulating the ocean current environment, the water flow velocity changes in the range of 0.3m / s to 1.0m / s within 24 hours, the pool is disturbed once every 2 hours, the water temperature is maintained at 12℃ to 18℃ during the acclimation process, the dissolved oxygen in the water is ≥6mg / L, and the resumption of normal feeding of rainbow trout fry in the ocean current environment is used as a sign that the ocean current acclimation is complete.

[0008] Optional feeding method during the growing stage: when the surface water temperature in the sea area is lower than 6℃, the feed feeding rate is 0.1%~0.5%, and feeding is done once a day; when the water temperature is 6℃~18℃, the feed feeding rate is 0.3%~0.8%, and feeding is done twice a day; when the water temperature is 19℃~20℃, feed a small amount every day; do not feed when the water temperature is higher than 20℃.

[0009] Optional feeding method during the growing stage: when the water temperature is below 6℃, above 20℃, or before and after a gale of 8 or above, add vitamins, probiotics, immune enhancers, etc. to the feed and feed for 3 to 5 days to improve the ability to resist stress.

[0010] Optionally, the net cage includes a frame, a net, and a feeding component. The net is laid in the frame and fixedly installed to the frame. The height of the net above the water surface is ≥3m, and the height of the net below the water surface is ≥6m. An anti-escape net is fixedly installed on the top of the net cage.

[0011] Optionally, the feeding component is fixedly mounted on the top inner wall of the frame, the feeding component includes a support frame, a material storage assembly and a material spreading assembly; the material storage assembly includes a material storage box, multiple telescopic parts, multiple material doors, and a material guide plate, and multiple discharge ports are opened on the lower side wall of the material storage box, the material storage box is fixedly mounted on the support frame, the material door is slidably connected to the material storage box at the discharge port, the telescopic part is fixedly mounted on the outer side wall of the material storage box, the output shaft end of the telescopic part is fixedly mounted on the material door, one end of the material guide plate is fixedly mounted on the outer side wall of the material storage box, and the material guide plate is located below the discharge port.

[0012] Optionally, the material spreading assembly includes a servo motor, multiple support plates, and multiple material spreading plates, the servo motor is fixedly mounted on the support frame, one end of the support plate is fixedly connected to the support frame, the material spreading plate is located above the other end of the support plate, and the material spreading plate is rotatably connected to the support plate; each material spreading plate is respectively located at each discharge port of the material storage box, the servo motor is respectively connected to each material spreading plate, and the servo motor drives the material spreading plate to rotate locally.

[0013] Optionally, the material spreading assembly also includes a first gear, multiple second gears, multiple crank rods, and multiple linkage rods. The first gear is fixedly mounted on the output shaft end of the servo motor, and the second gear is rotatably mounted on the lower surface of the support plate. The first gear is meshed with the second gear. One end of the crank rod is hinged to the edge of the lower surface of the second gear away from the center of the circle, and the other end of the crank rod is hinged to the linkage rod. A rotating shaft is installed through the support plate and the material spreading plate, and the rotating shaft is rotatably connected to the support plate, and the rotating shaft is fixedly connected to the material spreading plate, and the lower end of the material spreading plate is fixedly connected to the linkage rod.

[0014] (III) Beneficial effects The present invention provides a seasonal and efficient method for growing large-sized rainbow trout in natural waters of northern China, which has the following beneficial effects: 1. A seasonal and efficient method for growing large-sized rainbow trout in northern natural waters. By using cages to carry out seasonal rainbow trout farming in temperate nearshore and deep sea areas, compared with the existing technology, fresh water resources are no longer consumed; cage farming is large-scale and has high yields.

[0015] 2. Based on the differences between the sea area and the land-based freshwater environment, the present invention conducts dual adaptive domestication of salinity and ocean current for large-sized rainbow trout fry before they are dropped into the sea, so that the rainbow trout species can adapt to the growth environment of seawater with a certain salinity and the ocean current environment in advance, which can effectively reduce the stress during and after the transportation of rainbow trout, shorten the time for the physical function recovery of rainbow trout after dropping into the sea, and is beneficial to improving the survival rate and growth rate of rainbow trout after dropping into the sea.

[0016] 3. This is a seasonal and efficient method for growing large-sized rainbow trout in natural waters of the north. By carrying out seasonal breeding of rainbow trout for about 7 months, the unfavorable factors in the growing process of rainbow trout in the sea area are eliminated by adopting the methods of breeding environment control, stress reduction in the breeding process, enhanced nutrition and scientific feeding, so as to ensure that rainbow trout achieves higher-quality growth in the short-cycle growing process and achieves the purpose of reaching the market specifications and quality before the high temperature period.

[0017] 4. The present invention uses large-sized rainbow trout seedlings cultured in freshwater as the breeding object, fully utilizes the cold water resources in my country's temperate waters, cultivates rainbow trout in the natural waters of the north, innovates the land-sea relay breeding model, and solves the problems of shortage of freshwater breeding resources and saturated production capacity of rainbow trout through optimal resource allocation, which is conducive to a substantial increase in the production capacity of large-sized domestic red meat rainbow trout.

[0018] 5. my country's temperate waters, especially those with a water depth of more than 30m, meet the national Class I seawater quality standards. The growing period of rainbow trout in the sea area is generally 7 to 8 months, which can effectively remove the earthy smell of freshwater rainbow trout and is conducive to the formation of better meat quality, taste and flavor. Its quality is more competitive in the market than imported seafood salmon and trout. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the three-dimensional structure of a net cage in a seasonal and efficient culture method for large-sized rainbow trout in natural waters of northern China according to the present invention; Figure 2 It is a schematic cross-sectional structural diagram of a storage box in a seasonal and efficient method for growing large-sized rainbow trout in natural waters of northern China according to the present invention; Figure 3 It is a schematic diagram of the three-dimensional structure of a support frame in a seasonal and efficient cultivation method for large-sized rainbow trout in natural waters of northern China according to the present invention; Figure 4 The present invention is a schematic diagram of the three-dimensional structure of a feeding plate in a seasonal and efficient cultivation method for large-sized rainbow trout in natural waters of northern China.

[0021] In the figure: 1. first ring beam; 2. oblique support rod; 3. second ring beam; 4. steel cylinder; 5. counterweight; 6. buoyancy box; 7. support frame; 8. storage box; 9. telescopic member; 10. material door; 11. material guide plate; 12. support plate; 13. material spreading plate; 14. first gear; 15. second gear; 16. crank rod; 17. linkage rod; 18. rotating shaft; 19. triangular material dividing block; 20. servo motor. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indications or implications.

[0023] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments.

[0024] See also Figures 1 to 4 The present invention provides a technical solution: a seasonal and efficient method for growing large-sized rainbow trout in northern natural waters, the method comprising the following contents: A. Breeding stage: includes domestication stage and growing stage; the domestication stage includes salinity adaptation domestication and ocean current adaptation domestication.

[0025] Among them, the domestication stage is used to domesticate rainbow trout fry in advance to adapt to salinity and ocean currents before they are dropped into the sea, so that the rainbow trout can adapt to the growth environment of seawater with a certain salinity and ocean currents in advance, which can effectively reduce the stress during and after the transportation of rainbow trout, shorten the time for the physical function of rainbow trout to recover after being dropped into the sea, and help improve the survival rate and growth rate of rainbow trout after being dropped into the sea. The cultivation stage refers to the period from the drop of rainbow trout to the harvest period.

[0026] B. Breeding facilities: Land-based breeding facilities are used for the domestication stage; cages are used for the growing stage. The aquaculture water volume in a single breeding facility in the growing stage is ≥1000m³, and the water depth of the sea area where the breeding facility is located is ≥15m.

[0027] Among them, the land-based domestication facilities use the existing rainbow trout fry breeding ponds, and the water inside the rainbow trout fry breeding ponds is in a flowing state. The cages include but are not limited to the existing gravity cages, truss cages, breeding vessels and other large-scale breeding facilities.

[0028] C. Salinity adaptive acclimatization: transfer the freshwater rainbow trout fry to a water environment with an initial salinity of 5PSU, and increase the salinity gradient by 5PSU every 24 hours until the salinity reaches 30PSU; during the salinity adaptive acclimatization process, the water temperature is maintained at 12℃~18℃, and the dissolved oxygen in the water is ≥8mg / L. The completion of salinity acclimatization is marked by the resumption of normal clustering and feeding of the rainbow trout fry.

[0029] D. Sea current adaptation: land-based acclimation facilities are used to simulate the sea current environment for sea current adaptation. During the simulation of the sea current environment, the water velocity changes within 24 hours from 0.3m / s to 1.0m / s, and the pool is disturbed once every 2 hours. During the acclimation process, the water temperature is maintained at 12℃ to 18℃, and the dissolved oxygen in the water is ≥6mg / L. The resumption of normal feeding in the sea current environment is regarded as the sign of the completion of sea current acclimation.

[0030] Among them, the land-based domestication facilities use existing rainbow trout fry breeding ponds to domesticate rainbow trout fry to adapt to ocean currents. The flow rate of the water inside the rainbow trout fry breeding pond is controlled by using water pumps and other equipment, and the rainbow trout fry breeding pond is shaken by hydraulic cylinders and other equipment to cause turbulence in the water inside the rainbow trout fry breeding pond, so that the water inside the rainbow trout fry breeding pond simulates the ocean current environment.

[0031] E. Basic environmental requirements for the sea area during the culture stage: Select natural sea areas near the coast or deep sea. The water temperature in the natural sea area should be 0℃~20℃ for a period of no less than 7 months. The dissolved oxygen in the water should be ≥6mg / L, the salinity should be 28PSU~32PSU, the flow rate should be <1.5m / s, and the light intensity in the natural sea area should be 400Lux~500Lux.

[0032] Among them, the following conditions should be met when selecting rainbow trout breeding sea areas: the water temperature of natural sea areas should be 0℃~20℃ for a period of no less than 7 months, the dissolved oxygen in the water should be ≥6mg / L, the salinity should be 28PSU~32PSU (practical salinity unit), the flow rate should be <1.5m / s, and the light intensity in natural sea areas should be 400Lux~500Lux. In actual implementation in my country, the target sea area for rainbow trout breeding is selected at 38.5°N, the sea area of ​​Yantai Changdao Miaodao Archipelago, the water temperature should be 0℃~20℃ for 8 months throughout the year, the dissolved oxygen should be ≥6mg / L, the salinity should be 28~32, the flow rate should be <1.5m / s, the transparency should be good, and the light intensity should be 400Lux~500Lux.

[0033] F. Stocking when sea level drops: The window period for stocking is chosen when the surface water temperature in the natural sea area drops to 18°C ​​or below throughout the day, and the temperature difference between the target aquaculture sea area and the water environment of the land-based acclimation facility is ≤2°C, and the salinity difference is ≤3PSU.

[0034] Among them, rainbow trout are released into the sea after being adapted to salinity and ocean currents. The window period for releasing fry is chosen when the surface water temperature in the natural sea area drops to 18°C ​​or below throughout the day, and the temperature difference between the target breeding sea area and the water environment of the land-based acclimation facility is ≤2°C, and the salinity difference is ≤3PSU.

[0035] G. Stocking density during the growing stage: The weight specification of a single rainbow trout fry when stocked is 1.0kg~1.5kg; the initial stocking density is 3kg / m³~5kg / m³; the maximum stocking density is 12kg / m³~15kg / m³.

[0036] Among them, the maximum breeding density of near-shore gravity cages shall not exceed 12kg / m³, and that of deep-sea truss cages shall not exceed 15kg / m³.

[0037] H. Feeding method in the rearing stage: Use artificial compound feed throughout the whole feeding process, with crude protein content ≥45%, crude fat content ≥20%, and astaxanthin content of 40mg / kg; 3 months before listing, the crude fat content in the feed is increased to more than 25%, and the astaxanthin content in the feed is increased to 80mg / kg.

[0038] When the surface water temperature in the sea area is lower than 6℃, the feed feeding rate is 0.1%~0.5%, and feeding is done once a day; when the water temperature is 6℃~18℃, the feed feeding rate is 0.3%~0.8%, and feeding is done twice a day; when the water temperature is 19℃~20℃, feed a small amount every day; do not feed when the water temperature is higher than 20℃.

[0039] When the water temperature is lower than 6℃, higher than 20℃, or before and after strong winds of level 8 or above, add vitamins, probiotics, immune enhancers, etc. to the feed and feed it for 3 to 5 days to improve the ability to resist stress.

[0040] I. Harvesting: Rainbow trout should be harvested before the surface water temperature in the sea area rises to 22℃ throughout the day.

[0041] Specifically, the net cage includes a frame, a net, and a feeding component. The net is laid in the frame and fixedly installed to the frame. The height of the net above the water surface is ≥3m, and the height of the net below the water surface is ≥6m. An anti-escape net is fixedly installed on the top of the net cage.

[0042] Among them, the net is used to isolate the breeding area to prevent rainbow trout from escaping. The frame includes a first ring beam 1, a second ring beam 3, a plurality of oblique support rods 2, and a plurality of steel cylinders 4. The first ring beam 1 and the second ring beam 3 are longitudinally parallel. The upper end of the steel cylinder 4 is fixedly installed with the second ring beam 3, and the lower end of the steel cylinder 4 is fixedly installed with the first ring beam 1. The interior of the steel cylinder 4 is in the shape of a closed cavity, and the steel cylinder 4 has a certain buoyancy in the sea water. The upper and lower ends of the oblique support rods 2 are respectively fixedly installed with the second ring beam 3 and the first ring beam 1. The oblique support rods 2 are in an inclined state, and each oblique support rod 2 is used to strengthen the stability of the frame. A plurality of counterweights 5 are fixedly installed below the first ring beam 1. The frame is fixed to the nearshore or deep sea area by an anchor chain. The feeding component is used to feed a large area of ​​the breeding area in the net cage. A plurality of buoyancy tanks 6 are fixedly installed on the second ring beam 3.

[0043] To be further specific, the feeding component is fixedly mounted on the top inner wall of the frame, and the feeding component includes a support frame 7, a material storage assembly and a material spreading assembly; the material storage assembly includes a material storage box 8, multiple telescopic parts 9, multiple material doors 10, and a material guide plate 11. Multiple discharge ports are opened on the lower side wall of the material storage box 8, the material storage box 8 is fixedly mounted on the support frame 7, the material door 10 is slidably connected to the material storage box 8 at the discharge port, the telescopic part 9 is fixedly mounted on the outer wall of the material storage box 8, the output shaft end of the telescopic part 9 is fixedly mounted on the material door 10, one end of the material guide plate 11 is fixedly mounted on the outer wall of the material storage box 8, and the material guide plate 11 is located below the discharge port.

[0044] The telescopic member 9 includes but is not limited to a servo electric cylinder, etc. The telescopic member 9 is used to drive the material door 10 to move up and down. After the material door 10 rises, it no longer blocks the discharge port of the storage box 8. The feed in the storage box 8 rolls out through the discharge port. The guide plate 11 is used to guide the feed.

[0045] More specifically, the material spreading assembly includes a servo motor 20, a plurality of support plates 12, and a plurality of material spreading plates 13. The servo motor 20 is fixedly mounted on the support frame 7, one end of the support plate 12 is fixedly connected to the support frame 7, the material spreading plate 13 is located above the other end of the support plate 12, and the material spreading plate 13 is rotatably connected to the support plate 12; each material spreading plate 13 is respectively located at each discharge port of the storage box 8, and the servo motor 20 is respectively connected to each material spreading plate 13 in a transmission manner, and the servo motor 20 drives the material spreading plate 13 to rotate partially. A plurality of triangular material dividing blocks 19 are fixedly connected to the upper surface of the material spreading plate 13, and the triangular material dividing blocks 19 are used for diversion to prevent the feed from falling in a concentrated manner.

[0046] Among them, the feed rolling down from the guide plate 11 falls onto the scattering plate 13, and the scattering plate 13 is driven to rotate by the servo motor 20, so that the lower end of the scattering plate 13 is in a local rotation state, and the feed is scattered at the outlet at the lower end of the scattering plate 13. Since the scattering plate 13 is in a local rotation and swinging state, the feed can be scattered over a larger range, so that the feed can be fed over a large area, avoiding the concentrated competition of individual rainbow trout for food.

[0047] More specifically, the material spreading assembly also includes a first gear 14, multiple second gears 15, multiple crank rods 16, and multiple connecting rods 17. The first gear 14 is fixedly mounted on the output shaft end of the servo motor 20, and the second gear 15 is rotatably mounted on the lower surface of the support plate 12. The first gear 14 is meshed with the second gear 15. One end of the crank rod 16 is hinged to the edge of the lower surface of the second gear 15 away from the center of the circle, and the other end of the crank rod 16 is hinged to the connecting rod 17. A rotating shaft 18 is installed through the support plate 12 and the material spreading plate 13. The rotating shaft 18 is rotatably connected to the support plate 12, and the rotating shaft 18 is fixedly connected to the material spreading plate 13. The lower end of the material spreading plate 13 is fixedly connected to the connecting rod 17.

[0048] Among them, after the servo motor 20 is started, it drives the first gear 14 to rotate, and the first gear 14 pushes the second gear 15 to rotate. During the rotation process, the second gear 15 pulls the crank rod 16 to move horizontally, and the crank rod 16 pulls the push-pull linkage rod 17, so that the linkage rod 17 can be in a state of partial swinging around the rotating shaft 18. At the same time, the linkage rod 17 drives the rotating shaft 18 to rotate partially, and the rotating shaft 18 drives the spreading plate 13 to rotate partially. The spreading plate 13 is in a state of partial rotation and swinging, which can make the feed spreading range larger, so that the feed can be fed over a large area to avoid individual rainbow trout from competing for food.

[0049] In specific implementation, this technical solution also includes other parts and equipment to meet the normal breeding needs of rainbow trout in the sea area. In actual implementation, since the actual net cage is huge as a whole and the feeding parts are relatively small, in view of the need for illustration, the net cage is scaled and drawn in the attached figure, and the feeding parts are enlarged and drawn in the attached figure. The attached figure of this technical solution is used as a display of the structural principle.

[0050] Embodiment: In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in combination with actual specific implementation methods in reality.

[0051] (1) The target sea area for rainbow trout culture is selected at 38.5°N, in the waters of the Miaodao Islands of Changdao, Yantai. The water temperature is 0℃~20℃ for 8 months throughout the year, with dissolved oxygen ≥6mg / L, salinity 28PSU~32PSU, flow velocity <1.5m / s, good transparency, and light intensity 400Lux~500Lux.

[0052] (2) The rainbow trout culture facilities use truss-type floating cages. The aquaculture water volume of a single cage is 10,000 m³. The cages are arranged in sea areas with a depth of more than 20 m. The height of the net above the water surface is 3 m, and the height of the net below the water surface is 6 m. The top of the cage is covered with an escape-proof net.

[0053] (3) Around the end of September, large-sized rainbow trout fry with an average weight of 0.8 to 1.0 kg from freshwater farming were transferred to the acclimatization base before being dropped to the sea. They were kept for 2 days before resuming normal feeding.

[0054] (4) After resuming normal feeding for 1 week, stop feeding for 2 days and start salinity adaptation. The acclimatization method is as follows: the initial salinity is 5 PSU, and the salinity gradient is increased by 5 PSU every 24 hours until the salinity reaches 30 PSU. During the salinization process, the water temperature is maintained at 12℃~18℃ and the dissolved oxygen is ≥8 mg / L. The salinity transition is completed in 5 days, and normal feeding is resumed after 2 days.

[0055] (5) After resuming normal feeding for 1 week, stop feeding for 2 days and start adapting to the ocean current. The acclimation method is to simulate the change of ocean current velocity and direction by adjusting the water circulation rate and periodically pushing the pool disturbance. The velocity change range is 0.3m / s~1.0m / s within 24 hours, and the pool disturbance is pushed once every 2 hours. During the acclimation process, the water temperature is maintained at 12℃~18℃ and the dissolved oxygen is ≥6mg / L. After acclimating to the ocean current for 3 days, resume normal feeding. After 1 week of normal feeding, release the fish into the sea.

[0056] (6) In early November, when the surface water temperature in the target aquaculture area dropped to 18°C ​​throughout the day, rainbow trout fry were released into the sea. At this time, the water temperature of the land-based acclimation facility was 16°C to 18°C ​​and the salinity was 30. The average weight of the released fry was about 1.0 kg, and the initial density was 3 kg / m³. Artificial compound feed was used throughout the process, with a crude protein content of ≥45%, a crude fat content of ≥20%, and an astaxanthin content of 40 mg / kg. The feed formula was adjusted in early April of the following year, with the crude fat content of the feed increased to more than 25% and the astaxanthin content of the feed increased to 80 mg / kg.

[0057] (7) During the growth of rainbow trout, the water temperature changes from 3℃ to 21℃. When the surface water temperature in the sea area is lower than 6℃, the feed rate is 0.1% to 0.5%, and the fish are fed once a day; when the water temperature is 6℃ to 18℃, the feed rate is 0.3% to 0.8%, and the fish are fed twice a day; when the water temperature is 19℃ to 20℃, a small amount of feed is fed every day; when the water temperature is higher than 20℃, no feed is given. When the water temperature is lower than 6℃, higher than 20℃, or before and after a gale of force 8 or above, vitamins, probiotics, immune enhancers, etc. are added to the feed and the fish are fed continuously for 3 to 5 days to improve their ability to resist stress.

[0058] (8) Harvesting begins when the surface water temperature in the sea area reaches a maximum of 18°C ​​at the end of June of the following year, and all harvesting is completed before the surface water temperature in the sea area reaches 22°C. When rainbow trout are harvested, the stocking density is 12kg / m³, the average weight is 2.8kg, the survival rate is 93.6%, the meat color is 28-30, the muscle protein content is 20%, and the fat content is 10%. The quality is comparable to the best-reputation Norwegian salmon on the market, and at the same time, it has more advantages in terms of freshness and taste.

[0059] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A seasonal and efficient method for growing large-sized rainbow trout in northern natural waters, characterized in that: The method comprises the following contents: A. Aquaculture stage: including domestication stage and cultivation stage; wherein the domestication stage includes salinity adaptation domestication and ocean current adaptation domestication; B. Breeding facilities: Land-based breeding facilities are used for breeding facilities in the domestication stage; cages are used for breeding facilities in the grow-out stage. The aquaculture water volume in a single breeding facility in the grow-out stage is ≥1000m³, and the water depth of the sea area where the breeding facility is located is ≥15m; C. Salinity adaptation: transfer freshwater rainbow trout fry to a water environment with an initial salinity of 5PSU, and increase the salinity gradient by 5PSU every 24 hours until the salinity reaches 30PSU; during the salinity adaptation process, the water temperature is maintained at 12℃~18℃, and the dissolved oxygen in the water is ≥8mg / L. The completion of salinity adaptation is marked by the restoration of normal clustering and feeding of rainbow trout fry; D. Sea current adaptation: Use land-based adaptation facilities to simulate the sea current environment and conduct sea current adaptation; E. Basic environmental requirements for the sea area during the culture stage: Choose natural sea areas near the coast or deep sea. The water temperature of the natural sea area should be 0℃~20℃ for a period of not less than 7 months. The dissolved oxygen in the water should be ≥6mg / L, the salinity should be 28PSU~32PSU, the flow rate should be <1.5m / s, and the light intensity of the natural sea area should be 400Lux~500Lux. F. Stocking at low sea level: Stocking is carried out when the surface water temperature in the natural sea area drops to 18°C ​​or below throughout the day, and the temperature difference between the target aquaculture sea area and the water environment of the land-based acclimation facility is ≤2°C, and the salinity difference is ≤3PSU; G. Stocking density in the grow-out stage: the stocking specification is 1.0kg to 1.5kg, the initial stocking density is 3kg / m³ to 5kg / m³; the maximum stocking density is 12kg / m³ to 15kg / m³; H. Feeding method in the growing stage: artificial compound feed is used throughout the whole feeding process, with crude protein content ≥45%, crude fat content ≥20%, and astaxanthin content of 40mg / kg; 3 months before listing, the crude fat content in the feed is increased to more than 25%, and the astaxanthin content in the feed is increased to 80mg / kg; I. Harvesting: Rainbow trout should be harvested before the surface water temperature in the sea area rises to 22℃ throughout the day.

2. The seasonal and efficient method for growing large-sized rainbow trout in northern natural waters according to claim 1, characterized in that: During the simulated ocean current environment, the water flow velocity varied from 0.3m / s to 1.0m / s within 24 hours, the pool was disturbed once every 2 hours, the water temperature was maintained at 12℃ to 18℃ during the acclimation process, and the dissolved oxygen in the water was ≥6mg / L. The resumption of normal feeding of rainbow trout fry in the ocean current environment was regarded as the sign of the completion of ocean current acclimation.

3. The seasonal and efficient cultivation method for large-sized rainbow trout in northern natural waters according to claim 1 is characterized by: Feeding method during the growing stage: when the surface water temperature in the sea area is lower than 6℃, the feed feeding rate is 0.1%~0.5%, and feeding is done once a day; when the water temperature is 6℃~18℃, the feed feeding rate is 0.3%~0.8%, and feeding is done twice a day; when the water temperature is 19℃~20℃, feed a small amount every day; do not feed when the water temperature is higher than 20℃.

4. The seasonal and efficient method for growing large-sized rainbow trout in northern natural waters according to claim 1, characterized in that: Feeding method during the growing stage: When the water temperature is below 6℃, above 20℃, or before and after a gale of 8 or above, add vitamins, probiotics, immune enhancers, etc. to the feed and feed it for 3 to 5 days to improve the ability to resist stress.

5. The seasonal and efficient method for growing large-sized rainbow trout in northern natural waters according to claim 1, characterized in that: The net cage includes a frame, a net, and a feeding component. The net is laid in the frame and fixedly installed to the frame. The height of the net above the water surface is ≥3m, and the height of the net below the water surface is ≥6m. An anti-escape net is fixedly installed on the top of the net cage.

6. A seasonal and efficient method for growing large-sized rainbow trout in northern natural waters according to claim 5, characterized in that: The feeding component is fixedly mounted on the top inner side wall of the frame, and the feeding component comprises a support frame (7), a material storage component and a material spreading component; the material storage component comprises a material storage box (8), a plurality of telescopic parts (9), a plurality of material doors (10), and a material guide plate (11); a plurality of discharge ports are opened on the lower side wall of the material storage box (8); the material storage box (8) is fixedly mounted on the support frame (7); the material door (10) is slidably connected to the material storage box (8) at the discharge port; the telescopic part (9) is fixedly mounted on the outer side wall of the material storage box (8); the output shaft end of the telescopic part (9) is fixedly mounted on the material door (10); one end of the material guide plate (11) is fixedly mounted on the outer side wall of the material storage box (8), and the material guide plate (11) is located below the discharge port.

7. A seasonal and efficient method for growing large-sized rainbow trout in northern natural waters according to claim 6, characterized in that: The material spreading assembly comprises a servo motor (20), a plurality of support plates (12), and a plurality of material spreading plates (13); the servo motor (20) is fixedly mounted on a support frame (7); one end of the support plate (12) is fixedly connected to the support frame (7); the material spreading plate (13) is located above the other end of the support plate (12), and the material spreading plate (13) is rotatably connected to the support plate (12); each material spreading plate (13) is respectively located at each material outlet of the material storage box (8); the servo motor (20) is respectively transmission-connected to each material spreading plate (13); and the servo motor (20) drives the material spreading plate (13) to partially rotate.

8. The seasonal and efficient method for growing large-sized rainbow trout in northern natural waters according to claim 7, characterized in that: The material spreading assembly further comprises a first gear (14), a plurality of second gears (15), a plurality of crank rods (16), and a plurality of linkage rods (17); the first gear (14) is fixedly mounted on the output shaft end of the servo motor (20); the second gear (15) is rotatably mounted on the lower surface of the support plate (12); the first gear (14) is meshed with the second gear (15); one end of the crank rod (16) is hinged to the edge of the lower surface of the second gear (15) away from the center of the circle; the other end of the crank rod (16) is hinged to the linkage rod (17); a rotating shaft (18) is installed through the support plate (12) and the material spreading plate (13); the rotating shaft (18) is rotatably connected to the support plate (12); the rotating shaft (18) is fixedly connected to the material spreading plate (13); and the lower end of the material spreading plate (13) is fixedly connected to the linkage rod (17).

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