CN114521529A

CN114521529A - Land-based circulating water culture system and culture method for tunas of yellow fins

Info

Publication number: CN114521529A
Application number: CN202210179074.0A
Authority: CN
Inventors: 马振华; 于刚; 秦传新
Original assignee: Sanya Tropical Fisheries Research Institute
Current assignee: Sanya Tropical Fisheries Research Institute
Priority date: 2022-02-25
Filing date: 2022-02-25
Publication date: 2022-05-24
Anticipated expiration: 2042-02-25
Also published as: CN114521529B

Abstract

The invention discloses a land-based circulating water culture system and a culture method for tuna yellow fins, wherein the culture system comprises a culture pond, a traditional biological treatment circulating water system and a photoelectrochemical water treatment system are connected outside the culture pond in parallel, the pond of the culture pond adopts an arc-shaped corner design, three of four wall surfaces on the side surface of the pond form a physical bubble wall, and the remaining one wall surface is provided with a glass observation window; air supply pipes are laid along the edges of the bottom parts of the three physical bubble walls, and a plurality of air outlet holes are uniformly formed in the top parts of the air supply pipes along the axial direction of the air supply pipes; the top of any one side wall of the culture pond is provided with a weak light lamp. The whole culture system is stable, the water treatment system is efficient and stable, the water treatment efficiency can be adjusted according to the biological characteristics, ingestion and growth of the yellow fin tuna in culture, the effects of energy conservation and emission reduction are realized, and the use of the whole culture system is not influenced when the water treatment system is maintained. The whole system realizes 100 percent circulation and reduces pollution to the maximum extent.

Description

Land-based circulating water culture system and culture method for tunas of yellow fins

Technical Field

The invention relates to the technical field of aquaculture, in particular to a land-based recirculating aquaculture system and method for tuna finches.

Background

Tuna is rich in protein, fat and vitamin D, and has high contents of minerals such as calcium, phosphorus and iron. Tuna back contains a large amount of EPA and the front middle abdomen contains rich DHA. The fish contains DHA in proportion to the crown of fish, and is an excellent brain-strengthening food. Tuna contains a large amount of myoglobin, cytochrome and the like, most of fatty acid is unsaturated fatty acid, and meanwhile, the tuna is a green pollution-free healthy food recommended by the International society for nutrition, can strengthen the brain, strengthen the muscles and bones, prevent and treat cardiovascular diseases, improve the liver function and prevent and treat anemia after being eaten for a long time, and is a very healthy high-quality food material.

However, most tunas inhabit sea areas with water depths of 100-400 m. Generally, in terms of biological classification, tuna in a broad sense means about 30 species of fishes belonging to the family mackerel, family swordtail and family swordfish among the fish species. The tuna with yellow fins accounts for 35% of the worldwide production of tuna, and most of the tuna is used for preparing canned, fresh and frozen products. Furthermore, migration of tuna is related to seasonal changes in ocean currents, and in tropical rainy seasons, tuna is far away from relatively light coastal waters and migrates to high salinity sea areas, and the water depth is as high as 160 meters, so artificial breeding is less.

Although the sources of the tunas in the market are mainly wild, the economic value of the tunas is very high, so people constantly search for the culture technology of the tunas to really realize artificial culture of the tunas.

Disclosure of Invention

In view of the above, the invention provides a yellow fin tuna land-based recirculating aquaculture system and a culture method, and the specific technical scheme is as follows:

the invention provides a land-based circulating water culture system for tunas in yellow fins, which comprises a culture pond, wherein a traditional biological treatment circulating water system and a photoelectrochemical water treatment system are connected outside the culture pond in parallel, the interior of the culture pond adopts an arc-shaped corner design, three of four wall surfaces on the side surface of the culture pond form a physical bubble wall, and the remaining one wall surface is provided with a glass observation window; air supply pipes are laid along the edges of the bottoms of the three physical bubble walls, and a plurality of air outlet holes are uniformly formed in the tops of the air supply pipes along the axial direction of the air supply pipes; and a weak light lamp is installed at the top of any one side wall surface of the culture pond.

According to the invention, the traditional biological treatment circulating water system and the photoelectrochemical water treatment system are connected in parallel, so that the problem that the traditional circulating water treatment system depends on the biological bag for nitrification and denitrification to treat the culture water is solved, the culture system can still adopt the photoelectrochemical water treatment system to treat the water quality under the condition that the biological bag is not prepared, and the water treatment efficiency is effectively improved.

The arc-shaped corner design is adopted in the culture pond, so that water can conveniently flow in the culture pond in a rotating manner; the three wall surfaces form a physical bubble wall, so that air supply and oxygenation are realized, poor vision is provided for the yellow fin tunas, and the yellow fin tunas moving at high speed can be effectively prevented from colliding with the wall to cause death.

Preferably, the sum of the daily water treatment capacity of the traditional biological treatment circulating water system and the daily water treatment capacity of the photoelectrochemical water treatment system is 200-1000% of the culture water body in the culture pond.

Preferably, the traditional biological treatment circulating water system comprises a mechanical filtering device connected with one of the outlets of the water outlet pipes of the culture pond, the water outlet end of the mechanical filtering device is sequentially connected with a water return pond, a protein separator, a biological bag and an ultraviolet disinfection device, and the water outlet end of the ultraviolet disinfection device is connected with the first water return pipe of the culture pond; the protein separator is also connected with an ozone generator which leads ozone into the inner cavity of the protein separator; a first water pump is arranged on a connecting pipeline between the mechanical filtering device and the water return pool, and a second water pump is arranged on a connecting pipeline between the water return pool and the protein separator; the installation height of the biological bag is higher than that of the culture pond.

Preferably, the photoelectrochemical water treatment system comprises a photoelectrochemical processor connected with the other outlet of the water outlet pipe of the culture pond, the water outlet end of the photoelectrochemical processor is connected with the water inlet at the upper part of the sand pond, the upper part in the sand pond is paved with filter substances, and the bottom of the photoelectrochemical processor is provided with a nano aeration disc; a water outlet at the lower part of the sand pond is connected with a second water return pipe of the culture pond; a third water pump is arranged on a connecting pipeline between the culture pond and the photoelectrochemistry processor, and a fourth water pump is arranged on a connecting pipeline between the sand pond and the culture pond; the photoelectrochemistry processor is also externally connected with an air compressor which leads compressed air into the inner cavity of the photoelectrochemistry processor.

Preferably, a curved screen for filtering large particle impurities in water is installed in the mechanical filtering device.

Preferably, the ultraviolet disinfection device is a pipeline with ultraviolet disinfection lamps distributed inside.

Preferably, the filtering material in the sand pool is divided into three layers from top to bottom, namely an activated carbon layer, a coral sand layer and a quartz sand layer.

The invention also provides a land-based recirculating aquaculture method for the tuna finches, which is characterized by comprising the following steps of:

s1, setting the culture density in the culture pond to be 30-60 tails/120 cubic meters;

s2, continuously operating the traditional biological treatment circulating water system and the photoelectrochemical water treatment system at the same time;

s3, when the culture pond enters a dark period, providing a weak light source with light intensity less than 120lx for the culture pond;

s4, feeding the tunas with the yellow fin in the culture pond twice a day by adopting a satiating method;

s5, selecting 3 days every month, injecting the allicin into feed fish after being melted with water, and feeding;

s6, adding 20-25 tails of penaeus monodon with the length of 10cm into the culture pond, and cleaning residual bait and excrement.

Preferably, the feed fish is tuna, horse mackerel or decapterus maruadsi, fresh feed fish is purchased, sterilized by fresh water ozone, frozen in a freezer at the temperature of-20 ℃ for 1-2 weeks and fed; before feeding, the feed fish is cut into fish sections with the width of 3-10 cm, and the width of the feed fish sections is gradually increased along with the growth of the tuna finfish.

Preferably, in step S5, the effective concentration of allicin in the feed fish meat is 0.1 g/kg.

The invention realizes land-based circulating water culture of the tuna finfish, the whole culture system is stable, the water treatment system is efficient and stable, the water treatment efficiency can be adjusted according to the biological characteristics, ingestion and growth of the tuna finfish in culture, the effects of energy conservation and emission reduction are realized, and the use of the whole culture system is not influenced when the water treatment system is maintained. The whole system realizes 100 percent of circulation, and reduces pollution to the maximum extent.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a flow chart of the structure of a land-based recirculating aquaculture system for tuna finches of the present invention.

Fig. 2 is an appearance picture of the culture pond.

FIG. 3 is a top view of the culture pond.

FIG. 4 is a pictorial view of a water treatment system.

FIG. 5 is a live view of cultured tunas of yellow fin.

FIG. 6 is a table showing the statistics of the distance traveled by the juvenile tuna finches during ingestion in the present farming system.

FIG. 7 is a table showing the movement speed statistics of the juvenile tuna yellow fin during the non-feeding period in the present aquaculture system.

FIG. 8 is a table showing the statistics of the speed of the larvae of tuna yellowfin during feeding in the present aquaculture system.

FIG. 9 is a graph showing the relationship between feeding depth and time for the juvenile tuna finches in the present farming system.

FIG. 10 shows the water layer distribution of the juvenile tuna yellow fin during the non-feeding period in the present aquaculture system.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Example (b):

the invention provides a land-based circulating water culture system for tuna finches, which comprises a culture pond, wherein a traditional biological treatment circulating water system and a photoelectrochemical water treatment system are connected outside the culture pond in parallel. Specifically, in the present invention, a flow chart of the structure of the land-based recirculating aquaculture system for tuna finches is shown in fig. 1.

Wherein the content of the first and second substances,

the traditional biological treatment circulating water system comprises a mechanical filtering device connected with one of outlets of a water outlet pipe of a culture pond, wherein the water outlet end of the mechanical filtering device is sequentially connected with a water return pond, a protein separator, a biological bag and an ultraviolet disinfection device, and the water outlet end of the ultraviolet disinfection device is connected with a first water return pipe of the culture pond; the protein separator is also connected with an ozone generator which leads ozone into the inner cavity of the protein separator; a first water pump is arranged on a connecting pipeline between the mechanical filtering device and the water return pool, and a second water pump is arranged on a connecting pipeline between the water return pool and the protein separator; the installation height of the biological bag is higher than that of the culture pond.

In the embodiment of the invention, the arc-shaped sieve for filtering large-sized particle impurities in water is arranged in the mechanical filtering device.

In the embodiment of the invention, the ultraviolet disinfection device is a pipeline which is internally distributed with ultraviolet disinfection lamps.

In the traditional biological treatment circulating water system, the water return pool has a temporary buffering function; the protein separator makes protein in water into foam through aeration and removes the foam, and the ozone generator leads the generated ozone into the inner cavity of the protein separator to perform the sterilization function on the water flowing through; the biological bag is used for removing ammonia nitrogen, bacteria and the like in water, and because the installation height of the biological bag is higher than that of the culture pond, water flowing out of the biological bag flows into the ultraviolet disinfection device under the action of self gravity, flows around the ultraviolet disinfection lamp in the pipeline to be disinfected, and finally flows back into the culture pond to form a set of circulating water treatment system.

It should be noted that the protein separator, the bio-bag, the ultraviolet disinfection device and the ozone generator used in the conventional biological treatment circulating water system of the present invention are all the prior art, and therefore, the detailed description thereof is omitted.

The photoelectrochemical water treatment system comprises a photoelectrochemical processor connected with the other outlet of the water outlet pipe of the culture pond, the water outlet end of the photoelectrochemical processor is connected with the water inlet at the upper part of the sand pond, the upper part of the sand pond is paved with filter substances, and the bottom of the sand pond is provided with a nanometer aeration disc; a water outlet at the lower part of the sand pond is connected with a second water return pipe of the culture pond; a third water pump is installed on a connecting pipeline between the culture pond and the photoelectrochemistry processor, the third water pump is a big water pump, and a fourth water pump is installed on a connecting pipeline between the sand pond and the culture pond; the photoelectrochemistry processor is also externally connected with an air compressor which leads compressed air into the inner cavity of the photoelectrochemistry processor.

In the embodiment of the invention, the filter in the sand pool is divided into three layers from top to bottom, namely an activated carbon layer, a coral sand layer and a quartz sand layer. The height of the filtrate is generally about one meter.

In the photoelectrochemical water treatment system, the photoelectrochemical processor is the prior art, and the working principle is as follows: under the action of an electric field, chloride ions in water can be oxidized into free mature components such as chlorine, hypochlorous acid, hypochlorite and the like, the free mature components are diffused to the surface of negatively charged bacteria and penetrate into the bacteria through cell walls of the bacteria to play an oxidizing role, a bacterial matrix system is damaged, and the bacteria die in an electrocatalytic reaction; the electrolysis of water and the oxygen dissolved in the water generate short-lived intermediates on the electrode surface, i.e., ozone, hydrogen peroxide, and oxygen radicals, which are strongly oxidizing substances, and oxidize various components in the microbial cells, thereby causing irreversible changes in the microorganisms and causing death. The photoelectrochemical processor can process ammonia nitrogen, nitrite and the like in water and has a sterilization effect, and the air compressor sends compressed air into the photoelectrochemical processor, so that a large amount of bubbles can be generated and the internal reaction is promoted.

The problems of the traditional seawater biological treatment circulating water system in the prior art at present are as follows: 1. the occupied space is large, and the biological bag is usually designed according to the culture water body; 2. the system has poor anti-pressure capability, once the denitrifying bacteria of the nitrifying bacteria have problems, the whole system is broken down, normal water treatment cannot be carried out, the bacteria in the system are re-cultured for 20-30 days to recover the treatment capability, and the preparation time is too long after the system has problems, so that real-time treatment cannot be carried out.

The photoelectrochemistry water treatment system is a real-time water treatment system and can be used in a plug-and-play mode. However, the pH fluctuation in the system is large, and the pH in the aquaculture water can be reduced when the system is continuously used, so that the harm to the aquaculture organisms is caused. When started alone, the pH of the system decreased from 8.1 to 6.9-7.0 within 7 days.

The invention overcomes the defects of the two systems, the traditional biological treatment circulating water system and the photoelectrochemical water treatment system are connected in parallel, meanwhile, a functional buffer (namely a sand tank) is additionally arranged at the terminal of the photoelectrochemical water treatment system, after the three layers of activated carbon, coral sand and quartz sand are adopted for filtering, the pH value in the system is stabilized through aeration of a nanometer aeration disc (the pH value of the circulating water adopting the system is stabilized at 8.0 +/-1.1), and the system is standby at any time and is applied in real time.

In one embodiment of the present invention, two sets of water treatment systems are shown in FIG. 4.

The system of the invention is free from water change in 30 days of self-sustaining circulation (100-130L of seawater needs to be supplemented every 7 days, mainly to supplement water lost due to evaporation and mechanical filtration), the water treatment capacity is controllable and adjustable, and the sum of the daily water treatment capacity of the traditional biological treatment circulating water system and the photoelectrochemical water treatment system is 200-1000% of the culture water body in the culture pond.

In one embodiment of the invention, the structure of the culture pond is as shown in fig. 2 and fig. 3, the length of the culture pond is 8.6 meters, the width of the culture pond is 5.6 meters, and the depth of the culture pond is 2.8 meters, and an arc-shaped corner design which is convenient for water to flow in the culture pond in a rotating mode is adopted in the culture pond. The effective culture water body in the culture pond is 120 tons, and the sum of the treatment capacity of the traditional biological treatment circulating water system and the treatment capacity of the photoelectrochemical water treatment system is 240 tons to 1200 tons per day.

Three of the four wall surfaces on the side surface of the culture pond form physical bubble walls, and the upper part of the rest one wall surface is provided with a glass observation window. It is three the air supply pipe has all been laid along the limit to the subsides wall bottom of physics bubble wall, a plurality of ventholes, generally adjacent two have evenly been seted up along its axial direction in the top of air supply pipe interval between the venthole is 5 ~ 10 cm. The air pump supplies air and increases oxygen to the pond through the air supply pipe, adopts the mode of trilateral wall bottom air feed that pastes, forms physics bubble wall at three wall, and it is poor to provide the vision for yellow fin tuna, prevents effectively that the yellow fin tuna of high-speed motion from striking the wall and causing the death. Through practical verification, by adopting the design, no tuna with yellow fin hits the wall to die after 11 months of culture.

In the invention, the top of any one side wall surface of the culture pond is provided with a weak light lamp.

The invention also provides a culture method based on the system of the scheme, which comprises the following steps:

s4, feeding the tuna fins in the culture pond twice every day by adopting a satiation method, and stopping feeding after the active feeding of the tuna fins stops;

s5, selecting 3 days every month, injecting the dissolved allicin into the feed fish meat for feeding, wherein the effective concentration of the allicin in the feed fish meat is 0.1 g/kg;

s6, adding 20-25-tail penaeus monodon with length of 10cm into the culture pond for cleaning residual bait and excrement.

In the invention, the illumination period generally adopts 14 hours of light, 10 hours of dark and light, wherein the illumination intensity is 2000 lx. In the dark of 10 hours, 1 red light lamp can be adopted to provide a weak light source (the light intensity is less than 120lx) for the culture pond on one side of the culture pond and provide tour guide for the tuna finfish. Compared with no light supplement light source at night, the invention effectively avoids the body surface abrasion of the tuna in the yellow fin by adopting the weak light source for tour guide, effectively improves the survival rate of the tuna, and improves the survival rate by 72.13 percent compared with the survival rate without light supplement at night.

In the invention, the feed fish is tuna, horse mackerel or decapterus maruadsi, fresh feed fish is purchased, sterilized by fresh water ozone, frozen in a freezer at-20 ℃ for 1-2 weeks and then fed; before feeding, the feed fish is cut into fish sections with the width of 3-10 cm, and the width of the feed fish sections is gradually increased along with the growth of the tuna finfish.

The land-based recirculating aquaculture system and the aquaculture method for the tuna finches really realize land-based recirculating aquaculture of the tuna finches, and the outdoor scene of the tuna finches is shown in figure 5.

The actual land-based recirculating aquaculture data of the tuna finches obtained by the land-based recirculating aquaculture system and the land-based recirculating aquaculture method for the tuna finches are provided below.

Time: 3/month 2/2021 to 1/month 16/2022

Water temperature of 26-32 deg.C, ammonia nitrogen of 0.05, nitrite of 0.01, pH of 8.0 + -1.1, and DO of 6.5-7.0

Initial average body length 25.89 +/-7.89 cm, test body length 62.21 +/-10.75 cm, specific growth rate SGR (100) (lnW is last to lnW is first)/t (culture days) ═ 0.28%/day;

survival rate 71%, FCR (feed conversion factor) 20

Swimming speed variation of tuna fin

By monitoring the swimming speed change of the tuna pelagic during the whole day, as shown in a statistical chart of the moving speed of the tuna pelagic during the non-ingestion period in the culture system in fig. 7, the swimming speed of the tuna pelagic shows a rule that the tuna pelagic firstly rises, then falls, rises again and falls again on the whole from 6:00 to 18: 00. In all test points, the average swimming speed (0.62m/s) and the median (0.64m/s) at 6:00 were the smallest, and the average swimming speed reached the peak value at 1 st time from 8:00 to 10:00, the average swimming speed reached 1.18m/s, the valley value 0.80m/s at about 12:00, the peak value 0.98m/s at 2 nd time from about 16:00, and then the swimming speed gradually decreased along with the time. Only 8:00 and 18:00 were absent of outliers in all the experimental data sampling points.

FIG. 8 is a table showing the speed of movement of the juvenile tuna yellow fin during ingestion of food in the present farming system, wherein V1 represents the swimming speed of the initial food finding; v2 represents the speed of the food rushing toward the food in the ingestion of the food; v3 represents the escape velocity after ingestion.

FIG. 6 is a table showing the distance traveled by the juvenile tuna yellow fins during ingestion in the present farming system, L1 indicating the swimming distance for initial food discovery; l2 denotes the distance towards the food during ingestion; l3 represents the distance to escape after ingestion of a food.

As shown in the statistical tables in fig. 8 and 6, the swimming speed of the food found at the beginning of the tuna fry is 1.84 to 3.90m/s, the difference between the food intake speed and the food intake speed is significant (P <0.05), and the distance of the food found is 4.80 to 5.51 m; the speed of the juvenile tuna of the yellow fin towards food in ingestion is 0.98-1.54 m/s, and the sprint distance is 0.61-1.09 m; the juvenile tuna of the yellow fin can be thorned forward for a certain distance after ingestion, then turns and is ready to be ingested again, the escape speed is 0.77-1.67 m/s, the difference between the escape speed and the ingestion free speed is not significant (p is more than 0.05), and the escape distance is 0.40-1.47 m.

As shown in a graph of the relationship between the ingestion depth and the time of the juvenile tuna of the yellow fin in the culture system of FIG. 9, the initial feeding ingestion depth of the tuna of the yellow fin is 0.83-1.43 m, the ingestion depth gradually becomes shallow with the extension of the feeding time, the shallowest ingestion depth can reach 0.46m from the water surface, and the ingestion depth gradually becomes deep again after a period of stabilization, and the deepest ingestion depth can reach 1.94 m. Tuna yellow fins <0.7m from the pond had essentially no food intake. The relation between the ingestion water depth and the ingestion time of the juvenile tuna of the yellow fin: y is 0.0002x 2-0.021 x +1.168(R2 is 0.360). Overall, as feeding time extends, differences in feeding depth between individuals gradually increase.

As can be seen from the water layer distribution diagram of the juvenile tuna of the fin tuna in the non-ingestion period in the culture system in FIG. 10, the juvenile tuna of the fin tuna is deepest at a depth of 6:00 and has a water depth range of 1.9-2.6 m; the depth range is the largest at 8:00, 1.1-2.3 m, and the whole depth is shallow. The tuna fish school is the tightest at 14:00, and the depth range is the smallest, 1.7-2.2 m. The depth of the tuna at the lowest layer of the whole tuna swarm of the yellow fin is deepest at 6:00, and then the depth of each point is stable; the water depth of the tuna on the uppermost layer is in an obvious fluctuation state.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A land-based circulating water aquaculture system for tunas with yellow fins is characterized by comprising an aquaculture pond (1), wherein the outside of the aquaculture pond (1) is connected with a traditional biological treatment circulating water system and a photoelectrochemical water treatment system in parallel, the pond of the aquaculture pond (1) adopts an arc-shaped corner design, three of four wall surfaces on the side surface of the pond form a physical bubble wall, and the remaining wall surface is provided with a glass observation window; air supply pipes are laid along the edges of the bottoms of the three physical bubble walls, and a plurality of air outlet holes are uniformly formed in the tops of the air supply pipes along the axial direction of the air supply pipes; the top of any one side wall of the culture pond (1) is provided with a weak light lamp.

2. The land-based recirculating aquaculture system for tuna finches of claim 1, wherein the sum of daily water treatment capacities of the conventional biological treatment recirculating water system and the photoelectrochemical water treatment system is 200-1000% of the aquaculture water in the aquaculture pond (1).

3. The land-based circulating water aquaculture system for tuna yellow fins as claimed in claim 2, characterized in that the conventional biological treatment circulating water system comprises a mechanical filter device (2) connected with one of the outlets of the water outlet pipes of the aquaculture pond (1), the water outlet end of the mechanical filter device (2) is connected with a water return pond (4), a protein separator (6), a bio-bag (8) and an ultraviolet disinfection device (9) in sequence, and the water outlet end of the ultraviolet disinfection device (9) is connected with the first water return pipe of the aquaculture pond (1); the protein separator (6) is also connected with an ozone generator (7) which leads ozone into the inner cavity of the protein separator (6); a first water pump (3) is arranged on a connecting pipeline between the mechanical filtering device (2) and the water return pool (4), and a second water pump (5) is arranged on a connecting pipeline between the water return pool (4) and the protein separator (6); the installation height of the biological bag (8) is higher than that of the culture pond (1).

4. The land-based recirculating aquaculture system for tuna finches of claim 3, which comprises a photoelectrochemical water treatment system (11) connected with the other outlet of the water outlet pipe of the aquaculture pond (1), wherein the water outlet end of the photoelectrochemical water treatment system (11) is connected with the upper water inlet of a sand pond (13), the upper part in the sand pond (13) is paved with filter, and the bottom of the sand pond is provided with a nano aeration disc; a water outlet at the lower part of the sand pool (13) is connected with a second water return pipe of the culture pond (1); a third water pump (10) is arranged on a connecting pipeline between the culture pond (1) and the photoelectrochemical processor (11), and a fourth water pump (14) is arranged on a connecting pipeline between the sand pond (13) and the culture pond (1); the photoelectrochemistry processor (11) is also externally connected with an air compressor (12) which leads compressed air into the inner cavity of the photoelectrochemistry processor (11).

5. The land-based recirculating aquaculture system of tuna finches of claim 4, characterized in that said mechanical filter device (2) is equipped with sieve arcs for filtering large-sized particulate impurities in water.

6. The land-based recirculating aquaculture system for tuna finches of claim 4, wherein said ultraviolet disinfection device (9) is a tube with ultraviolet disinfection lamps inside.

7. The land-based recirculating aquaculture system for tuna yellow fins of claim 4, wherein the filtering material in the sand pond (13) is divided into three layers from top to bottom, namely an activated carbon layer, a coral sand layer and a quartz sand layer.

8. A land-based recirculating aquaculture method for tuna finches is characterized by comprising the following steps:

s1, setting the cultivation density in the cultivation pond (1) to be 30-60 tails/120 cubic meters;

s3, when the culture pond (1) enters a dark cycle, providing a weak light source with light intensity less than 120lx for the culture pond (1);

s4, feeding the tuna fins in the culture pond (1) twice a day by a satiating method;

s6, adding 20-25-tail penaeus monodon (10 cm) into the culture pond (1) for cleaning residual bait and excrement.

9. The land-based recirculating aquaculture method for tuna yellow-fin according to claim 8, wherein the feed fish is tuna, horse mackerel or decapterus maruadsi, fresh feed fish is sterilized by fresh water ozone after purchase, and then is frozen in a freezer at-20 ℃ for 1-2 weeks before feeding; before feeding, the feed fish is cut into fish sections with the width of 3-10 cm, and the width of the feed fish sections is gradually increased along with the growth of the tuna finfish.

10. The land-based recirculating aquaculture method of tuna finches of claim 8, wherein in step S5, the effective concentration of allicin in the feed fish meat is 0.1 g/kg.