Aquaculture method for aquatic organisms, aquaculture equipment for aquatic organisms and method for transferring aquaculture water

Abstract

To provide an aquaculture method and aquaculture equipment for aquatic organisms enabling stable aquaculture of aquatic organisms.SOLUTION: An aquaculture method for culturing aquatic organisms in aquaculture water W in a water tank 50, the aquaculture method for aquatic organisms, includes a step of suppressing bulking of the aquaculture water W by adding an oxidant to the aquaculture water W. Alternatively, there is provided aquaculture equipment 100 for aquatic organisms including a water tank 50 for storing aquaculture water W for culturing aquatic organisms, and an oxidant supply part 200 for adding an oxidant to the aquaculture water W, the aquaculture equipment for aquatic organisms configured to suppress bulking of the aquaculture water W in the water tank 50 by the oxidant.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for culturing aquatic organisms, an aquaculture facility for aquatic organisms, and a method for transferring breeding water.

Background Art

[0002] Regarding aquaculture facilities for growing fish, shellfish, or crustaceans in aquaculture tanks constructed on land, various facilities and devices have been developed. Patent Document 1 discloses an aquaculture facility that appropriately maintains the water quality of an aquaculture tank in an aquaculture facility using bioflocs by using a nitrifying bacteria immobilization material carrying nitrifying bacteria. Patent Document 2 discloses an aquaculture facility suitable for culturing shrimps by providing a heat-insulating house covering the aquaculture tank to reduce the burden of temperature management.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the aquaculture of aquatic organisms, if filamentous bacteria in the breeding water proliferate and cause bulking, there is a concern that solid matter floating in the breeding water will clog the gills of the aquatic organisms, increasing the mortality rate of the aquatic organisms during aquaculture. Therefore, the present disclosure provides an aquaculture method and an aquaculture facility for aquatic organisms that can stably perform aquaculture of aquatic organisms. In addition, a method for transferring breeding water that can efficiently perform aquaculture of aquatic organisms is provided.

Means for Solving the Problems

[0005] One aspect of the present disclosure provides a method for culturing aquatic organisms in breeding water in an aquarium, the method comprising a step of adding an oxidizing agent to the breeding water to suppress bulking of the breeding water.

[0006] The above method for culturing aquatic organisms includes a step of adding an oxidizing agent to the breeding water to suppress bulking. The oxidizing agent added to the breeding water suppresses the growth of filamentous bacteria that cause bulking. Therefore, by adding an oxidizing agent to the breeding water, bulking can be suppressed. As a result, the death of aquatic organisms can be suppressed, and the culturing of aquatic organisms can be stably carried out.

[0007] One aspect of the present disclosure provides an aquaculture facility for culturing aquatic organisms, the facility comprising an aquarium for containing breeding water for culturing aquatic organisms and an oxidizing agent supply unit for adding an oxidizing agent to the breeding water, wherein the oxidizing agent is configured to suppress bulking of the breeding water in the aquarium.

[0008] The above aquaculture facility for culturing aquatic organisms includes an oxidizing agent supply unit for supplying an oxidizing agent to the breeding water. The oxidizing agent supplied to the breeding water suppresses the growth of filamentous bacteria that cause bulking. Therefore, by using an aquaculture facility equipped with an oxidizing agent supply unit for supplying an oxidizing agent to the breeding water, bulking can be suppressed and aquatic organisms can be cultured. As a result, the death of aquatic organisms can be suppressed, and the culturing of aquatic organisms can be stably carried out.

[0009] One aspect of the present disclosure provides a method for transferring breeding water containing bioflocs, the method comprising a step of adding an oxidizing agent to the breeding water to obtain transfer breeding water in which bulking is suppressed, and a step of transferring the transfer breeding water to an aquarium for culturing aquatic organisms.

[0010] The above method for transferring the breeding water can transfer the breeding water containing bioflocs with suppressed bulking to another water tank. By having such a process, the breeding water added with an oxidizing agent can be used as the breeding water for transfer. Thereby, the breeding water containing bioflocs with suppressed bulking can be transferred to another water tank, and the bioflocs effective for aquaculture can be reused in another water tank. As a result, the aquaculture of aquatic organisms can be efficiently carried out.

Effects of the Invention

[0011] The present disclosure can provide an aquaculture method and aquaculture equipment capable of stably performing the aquaculture of aquatic organisms. In addition, a method for transferring breeding water capable of efficiently performing the aquaculture of aquatic organisms can be provided.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0013] Hereinafter, some embodiments of the present disclosure will be described. However, the following embodiments are examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. The upper limit value or lower limit value of the numerical range of the present disclosure may be replaced with any value shown in the examples. Also, numerical ranges obtained by arbitrarily combining the individually listed upper limit values and lower limit values are also included in the present disclosure. The materials or components exemplified in the present disclosure can be used alone or in combination of two or more unless otherwise specified. In the description, the same reference numerals are assigned to the same elements or elements having the same function, and duplicate descriptions are omitted. Also, the positional relationships such as up, down, left, and right used in the description are based on the positional relationships shown in the drawings unless otherwise specified.

[0014] A method for culturing aquatic organisms according to an embodiment is a culturing method for culturing aquatic organisms in breeding water in an aquarium, and includes a step of adding an oxidizing agent to the breeding water to suppress bulking of the breeding water.

[0015] In the step of suppressing bulking, the oxidizing agent added to the breeding water can kill filamentous bacteria, thereby suppressing bulking of the breeding water. In the present disclosure, "bulking" refers to the excessive growth of filamentous bacteria in bioflocs, which makes solid-liquid separation in water difficult to occur, and typically, SVI > 200 can be used. When filamentous bacteria grow, the cohesiveness of solids decreases or the viscosity of water increases, making it difficult for solids to settle in the breeding water. Solids that do not settle cause gill clogging of aquatic organisms and increase the mortality rate during culturing. Therefore, it is preferable to reduce the frequency of bulking. Thus, by including the step of suppressing bulking, the death of aquatic organisms during culturing can be suppressed.

[0016] In the present disclosure, the breeding water is water or an aqueous solution that is contained in an aquarium for culturing aquatic organisms and is used for breeding the aquatic organisms. The breeding water may contain at least one selected from the group consisting of fresh water, seawater, and brackish water. These can be appropriately selected according to the type of aquatic organisms to be bred. The seawater and the brackish water may be prepared using artificial seawater. The type of breeding water may be changed according to the breeding period from the egg stage to the shipping size.

[0017] In the present disclosure, an oxidizing agent refers to a substance that oxidizes other substances and is itself reduced. The oxidizing agent of the present disclosure may be any of a gas, a liquid, and a solid, but is preferably a liquid from the viewpoint of handleability. The oxidizing agent of the present disclosure includes not only the oxidizing agent itself, but also a solution obtained by dissolving the oxidizing agent in a solvent such as water, and a diluted solution diluted with a solvent such as water. The oxidizing agent may contain a chlorine-based oxidizing agent. Examples of the chlorine-based oxidizing agent include chlorine gas, chlorine dioxide, hypochlorous acid or its salts, chlorous acid or its salts, chloric acid or its salts, perchloric acid or its salts, chlorinated isocyanuric acid or its salts, etc. Examples of the salts include alkali metal hypochlorites such as sodium hypochlorite and potassium hypochlorite, alkaline earth metal hypochlorites such as calcium hypochlorite and barium hypochlorite, alkali metal chlorites such as sodium chlorite and potassium chlorite, alkaline earth metal chlorites such as barium chlorite, other metal chlorites such as nickel chlorite, ammonium chlorate, alkali metal chlorates such as sodium chlorate and potassium chlorate, alkaline earth metal chlorates such as calcium chlorate and barium chlorate, etc. These chlorine-based oxidizing agents may be used alone or in combination of two or more. From the viewpoints of bactericidal power against filamentous bacteria and handleability, etc., it is preferable to use sodium hypochlorite as the chlorine-based oxidizing agent.

[0018] The breeding water may contain bioflocs. In the present disclosure, a biofloc is an aggregate (floc) of microorganisms artificially created in the breeding water of an aquarium for aquatic organisms such as fish and crustaceans and used as food for the aquatic organisms. Bioflocs reduce the toxic ammonia and nitrite that increase due to feeding. By adding an oxidizing agent to the breeding water containing bioflocs, filamentous bacteria in the bioflocs can be sterilized, and bulking of the bioflocs can be suppressed. Thereby, it is possible to suppress the clogging of the gills of aquatic organisms by bioflocs and reduce the mortality rate of aquatic organisms.

[0019] Bioflocs may contain nitrifying bacteria. Examples of nitrifying bacteria include ammonia-oxidizing bacteria and nitrite-oxidizing bacteria. Ammonia-oxidizing bacteria are bacteria that oxidize ammonium ions in ammonia nitrogen in breeding water into nitrite ions under an aerobic atmosphere. Also, nitrite-oxidizing bacteria are bacteria that oxidize nitrite ions in nitrite nitrogen in breeding water into nitrate ions under an aerobic atmosphere. When bioflocs contain nitrifying bacteria, the C / N ratio of the breeding water can be appropriately adjusted, the water quality of the breeding water can be maintained at a high level, and the growth of aquatic organisms can be further promoted. Also, since the intake and discharge of seawater can be reduced, the environmental load in aquaculture can be reduced. The C / N ratio of the breeding water may be 10 or more, 9 or more, 8 or more, 7 or more, or 6 or more. By the C / N ratio of the breeding water being within the above range, the water quality can be maintained, and the growth of aquatic organisms can be further promoted.

[0020] Examples of nitrifying bacteria include Nitrobacter, Nitorospina, Nitorococcus, etc. However, the types of nitrifying bacteria are not limited to these, and can be appropriately selected in consideration of various conditions such as the type of aquatic organisms to be cultured, hydrogen ion index, dissolved oxygen, nitrogen concentration, culture density, size of the breeding aquarium (amount of breeding water), temperature, pH, etc. Nitrifying bacteria may be added directly to the breeding water, or may be added after being supported on an inorganic carrier.

[0021] The bacterial flora that constitutes the biofloc may include bacteria such as those belonging to the family Flavobacteriaceae, Saprospiraceae, Rhodobacteraceae, etc. By using such biofloc, it is possible to sufficiently promote the growth of aquatic organisms while appropriately maintaining the water quality of the breeding water.

[0022] The method for culturing aquatic organisms according to this embodiment may include a step of adjusting the supply amount of the oxidizing agent to the water tank based on at least one selected from the group consisting of information related to the bulking of the breeding water and information related to the function of the biofloc. The information related to the bulking of the breeding water may be a measured value related to the bulking. The information related to the function of the biofloc may be a measured value related to the function of the biofloc. The supply amount of the oxidizing agent to the water tank may be adjusted so that at least one selected from the group consisting of the measured value related to the bulking and the measured value related to the function of the biofloc is within a predetermined range. The adjustment of the supply amount of the oxidizing agent may be performed, for example, by automatically or manually changing the opening degree of a valve that adjusts the supply amount of the oxidizing agent. When the information related to the bulking is within a predetermined range, the supply amount of the oxidizing agent may not be adjusted. The supply of the oxidizing agent may be continuous or intermittent. Examples of the information related to the bulking include SVI, FV, and the mortality rate of aquatic organisms.

[0023] FV is the floc volume (mL) of the biofloc. SVI is the volume (mL / g) per gram of floc calculated as FV / TSS×1000. TSS is the dry weight (mg) of the floc. For example, selecting these as information related to the bulking, the supply amount of the oxidizing agent to the water tank may be adjusted so as to satisfy at least one selected from the group consisting of the following conditions (a), (b), and (c). By performing the step of adjusting the supply amount of such an oxidizing agent, the occurrence of bulking can be sufficiently suppressed, and the mortality of aquatic organisms can be further suppressed. (a) SVI ≦ 1211 mL / g (b) FV ≦ 350 mL (c) Mortality rate of the above aquatic organisms ≤ 0.59%

[0024] The SVI (mL / g) under condition (a) may be 1211 mL / g or less, may be 1000 mL / g or less, may be 800 mL / g or less, may be 500 mL / g or less, may be 200 mL / g or less, may be 100 mL / g or less, may be 80 mL / g or less, may be 60 mL / g or less, may be 50 mL / g or less, may be 40 mL / g or less. The larger the SVI, the larger the volume per mass, so the sedimentation of bioflocs is suppressed. Therefore, SVI can be used as an index for bulking. By having a step of adjusting the supply amount of the oxidizing agent so that SVI maintains the above range, it is possible to sufficiently suppress the increase in SVI and the occurrence of bulking. Therefore, the mortality rate of aquatic organisms can be reduced. From the viewpoint of sufficiently sedimenting bioflocs, SVI may be 5 mL / g or more, or may be 10 mL / g or more. An example of the numerical range of SVI may be 5 to 60 mL / g. Mortality occurs not only due to gill clogging by filamentous bacteria, but when SVI particularly exceeds 60 mL / g, more mortality due to gill clogging by filamentous bacteria is observed.

[0025] FV (mL) can be obtained, for example, by measuring 1 L of breeding water with a measuring instrument such as a 1 L volumetric cylinder and reading the volume of the sediment after standing for 30 minutes. TSS (mg) can be obtained, for example, by filtering 1 L of breeding water after measuring FV and measuring the weight after drying the sediment in a constant temperature bath at 100 °C for 1 hour.

[0026] The FV (mL) of condition (b) may be 350 mL or less, 250 mL or less, 150 mL or less, 100 mL or less, 80 mL or less, 60 mL or less, 40 mL or less, 25 mL or less, 20 mL or less, or 15 mL or less. The larger the FV, the more difficult it is for the bioflocs to settle and the more likely bulking is to occur. Therefore, like the SVI, the FV can also be used as an indicator of bulking. By having a step of adjusting the supply amount of the oxidizing agent so that the FV is maintained within the above range, the increase in FV can be sufficiently suppressed, and the occurrence of bulking can be effectively prevented. Therefore, the mortality rate of aquatic organisms can be sufficiently reduced, and the aquaculture of aquatic organisms can be carried out more stably. From the perspective of sufficiently precipitating the bioflocs, the FV may be 1 mL or more, or 2 mL or more. An example of the numerical range of the FV may be 1 to 25 mL. As the FV increases, more deaths due to filamentous bacteria clogging the gills are often observed. In particular, when it exceeds 25 mL, more deaths due to filamentous bacteria clogging the gills may be frequently observed.

[0027] The TSS (mg) may be 100 to 1000 mg. When the TSS is within this range, the bioflocs are sufficiently present in the breeding water, so the C / N ratio in the breeding water is easily adjusted to an appropriate range, and the growth of aquatic organisms can be promoted. In addition, the environmental load can be reduced. From the same perspective, the lower limit of the TSS (mg) may be 150 mg, 200 mg, 250 mg, or 300 mg. From the same perspective, the upper limit of the TSS (mg) may be 900 mg, 800 mg, 700 mg, 600 mg, or 500 mg.

[0028] In the present disclosure, the mortality rate refers to the average mortality rate over a total of three days including the days before and after the target day, unless otherwise specified. That is, the mortality rate is the average value of the daily mortality rates on each day. Regarding condition (c), the mortality rate of aquatic organisms may be 0.59% or less, may be 0.5% or less, may be 0.4% or less, or may be 0.3% or less. When bulking occurs in the breeding water containing bioflocs, it becomes difficult for the bioflocs to precipitate, causing the bioflocs to clog the gills of aquatic organisms and increasing the mortality rate. Therefore, the mortality rate can be used as an indicator of bulking. The daily mortality rate on which the above-mentioned mortality rate calculation is based can be obtained by the ratio of the estimated surviving number of tails on the measurement day to the number of dead tails on the measurement day. The estimated surviving number of tails on the measurement day can be obtained by subtracting the cumulative number of dead tails from the day before the measurement day from the number of aquatic organisms introduced into the aquarium. Also, the estimated surviving number of tails may be obtained by the following formula. Estimated surviving number of tails = Surviving number of tails on the previous day - Recovered dead number of tails - Unrecovered dead number of tails Unrecovered dead number of tails = Difference in the number of tails in the pond × Recovered dead number of tails / Total recovered dead number of tails Difference in the number of tails in the pond = Number of introduced tails - Number of landed tails - Total recovered dead number of tails

[0029] The number of live tails and the number of dead tails may be counted visually, or may be determined by taking an image of the rearing water and analyzing the image. The cause of death is gill clogging can be determined by visual inspection or image analysis, as the solid content of the biofloc is clogging the gills of the dead individuals. By having a step of adjusting the supply amount of oxidant so that the mortality rate is maintained within the above range, the occurrence of bulking can be suppressed, and an increase in the mortality rate of aquatic organisms can be suppressed. The mortality rate may be 0.01% or more. An example of the numerical range of the mortality rate may be 0.01 to 0.59%. In the present disclosure, when the aquatic organism is a crustacean, the resistance to death due to gill clogging may differ depending on the rearing stage. Since the frequency of molting is high in the rearing stage called juvenile shrimp, death can be avoided by molting before the gills become clogged. Therefore, even if the bulking is the same, there may be more deaths in larger individuals than in smaller individuals. For example, in the case of vannamei shrimp, when the body weight is 15g or more, 17g or more, 18g or more, or 20g or more, the molting frequency is low and therefore the risk of death due to bulking may be higher, and the present disclosure is effective.

[0030] The step of adjusting the amount of oxidant supplied to the aquarium may be performed using at least one selected from the group consisting of the above conditions (a), (b), and (c) as an index. For example, the step may be performed using only one or two of the conditions (a), (b), and (c) as indexes, or may be performed using all of the conditions (a), (b), and (c) as indexes. In this case, the SVI, FV, and daily mortality rate of aquatic organisms may be measured, and the amount of oxidant supplied to the aquarium may be adjusted if any one of the measurement results falls outside a predetermined range. If each measurement result is within the predetermined range, the amount of oxidant supplied does not need to be adjusted.

[0031] As another example of information related to bulking, the suspended concentration (MLSS) of bioflocs in the breeding water can be mentioned. The suspended concentration (MLSS) may be 500 mg / L or less, may be 400 mg / L or less, or may be 300 mg / L or less. By the MLSS being within the above range, it is possible to sufficiently suppress the occurrence of bulking due to an increase in the MLSS. Therefore, the mortality rate of aquatic organisms can be reduced. Also, from the viewpoint of sufficiently precipitating the bioflocs, the MLSS may be 10 mg / L or more, may be 50 mg / L or more, or may be 100 mg / L or more. An example of the range of the MLSS may be 10 to 500 mg / L. The supply amount of the oxidizing agent may be adjusted so that the MLSS maintains the above range. The MLSS can be measured using a commercially available sludge concentration meter.

[0032] Examples of information related to the function of bioflocs include the concentration of ammonia nitrogen (TAN) in the breeding water and the concentration of nitrite nitrogen (NO2-N). The supply amount of the oxidizing agent to the breeding water may be adjusted so that the concentration of ammonia nitrogen (TAN) in the breeding water is 5.0 mg / L or less and the concentration of nitrite nitrogen (NO2-N) is 30 mg / L or less. By the ammonia nitrogen and nitrite nitrogen being within the above range, the nitrifying bacteria in the bioflocs function sufficiently, and the harmful ammonia and nitrite generated in the breeding water can be sufficiently decomposed to maintain the water quality at a high level. From the viewpoint of maintaining the water quality at an even higher level, the concentration of TAN may be 2.0 mg / mL or less, may be 1.0 mg / mL or less, or may be 0.5 mg / mL or less. The supply amount of the oxidizing agent may be adjusted so that the concentration of TAN is within the above range. Also, from the viewpoint of reducing the influence of the oxidizing agent on the nitrifying bacteria and maintaining the function of the nitrifying bacteria, the concentration of TAN may be 0.01 mg / mL or more or may be 0.05 mg / mL or more. An example of the concentration range of TAN may be 0.01 to 5.0 mg / mL.

[0033] From the perspective of further maintaining water quality, the concentration of NO2-N may be 10 mg / mL or less, may be 1 mg / mL or less, or may be 0.5 mg / mL or less. The supply amount of the oxidizing agent may be adjusted to be within such a range. Also, from the perspective of reducing the impact of the oxidizing agent on nitrifying bacteria and maintaining the function of nitrifying bacteria, the concentration of NO2-N may be 0.01 mg / mL or more, or may be 0.02 mg / mL or more. An example of the concentration range of NO2-N may be 0.02 - 30 mg / mL. Thus, by adjusting the supply amount of the oxidizing agent based on the measurement results of the concentration of ammonia nitrogen (TAN) and the concentration of nitrite nitrogen (NO2-N), it is possible to avoid affecting the nitrifying bacteria in the biofloc and only sterilize the filamentous bacteria that cause bulking. Thereby, while suppressing the occurrence of bulking, the biofloc can be made to function sufficiently to further promote the growth of aquatic organisms. The concentrations of TAN and NO2-N can be determined, for example, by the Kjeldahl method, the ion electrode method, etc.

[0034] The dissolved oxygen content (DO) of the breeding water may be 3.0 - 8.0 mg / L, or may be 4.0 - 7.0 mg / L. When the DO is within this range, the water quality can be maintained at a high level, and the growth of aquatic organisms can be further promoted. The DO can be measured, for example, using a commercially available dissolved oxygen meter.

[0035] The pH of the breeding water may be 6.5 - 8.5, or may be 7.0 - 8.0. When the pH is within this range, an appropriate pH for the growth of aquatic organisms can be maintained, and the growth of aquatic organisms can be further promoted. The pH can be measured, for example, using a commercially available pH meter.

[0036] The method for culturing aquatic organisms according to this embodiment may include a step of mixing water and an oxidizing agent to obtain a diluted solution of the oxidizing agent. By mixing the obtained diluted solution with the breeding water in the water tank, bulking can be suppressed. The water used for preparing the diluted solution may be, for example, the water circulating in the water tank or the water newly introduced from the outside. In the step of obtaining the diluted solution, the water and the oxidizing agent are mixed in a facility separate from the breeding tank to prepare the diluted solution. The mixing of the diluted solution into the breeding water may be performed by adding the diluted solution to the breeding water in the water tank. By diluting and mixing the oxidizing agent, it is possible to prevent the aquatic organisms in the water tank from directly contacting a high-concentration oxidizing agent and suppress damage to the aquatic organisms.

[0037] Tap water may be used directly as the oxidizing agent. Since tap water contains sodium hypochlorite for sterilization, it corresponds to a diluted solution of the oxidizing agent. When using tap water, the tap water may be diluted with water different from the tap water to obtain diluted water. By using tap water, the step of obtaining the diluted water can be performed more simply. As an example of the method of adding the oxidizing agent to the water tank, there is a method of using the washing water generated when the inside of the water tank is washed with tap water as the breeding water in the water tank.

[0038] The concentration of the oxidizing agent in the diluted solution may be 0.01 to 10 wt%. When the concentration of the oxidizing agent is within the above range, it is possible to efficiently sterilize filamentous bacteria while sufficiently suppressing damage to aquatic organisms. Furthermore, it is possible to sufficiently maintain the nitrification function of nitrifying bacteria without over-sterilizing them. Thereby, while sterilizing filamentous bacteria to suppress bulking, it is possible to maintain nitrifying bacteria and perform biofloc culture. The lower limit of the concentration of the oxidizing agent in the diluted solution may be 0.1 wt% or more, and may be 1.0 wt% or more. The upper limit of the concentration of the oxidizing agent in the diluted solution may be 7.0 wt% or less, and may be 6.0 wt% or less.

[0039] The supply rate of the oxidizing agent (diluted solution) may be 10 to 200 mL / h, may be 25 to 150 mL / h, or may be 50 to 100 mL / h. At such a supply rate of the oxidizing agent, filamentous bacteria can be efficiently sterilized while preventing the oxidizing agent from directly hitting aquatic organisms, and damage to aquatic organisms can be suppressed.

[0040] The addition time of the oxidizing agent may be 1 to 5 hours, or may be 2 to 4 hours. At such a supply rate of the oxidizing agent, filamentous bacteria can be efficiently sterilized while preventing the oxidizing agent from directly hitting aquatic organisms, and damage to aquatic organisms can be suppressed.

[0041] In the breeding water of the aquarium, a first part where aquatic organisms can move and a second part where they cannot enter are provided. In the step of suppressing bulking, the oxidizing agent or a diluted solution containing the oxidizing agent may be added to the second part. The added oxidizing agent can damage aquatic organisms by directly contacting them. Therefore, by adding the oxidizing agent to the second part where aquatic organisms in the breeding water cannot enter, it is possible to prevent the added oxidizing agent from directly contacting the aquatic organisms. Examples of the member that partitions the first part and the second part include a partitioning member having a flow hole through which water can flow. The partitioning member may be, for example, a cage-like member.

[0042] The aquatic organisms cultured in this embodiment may be fish or crustaceans. The fish may include tilapia and catfish. The tilapia may include Nile tilapia, Mozambique tilapia, and Zil tilapia. The catfish may include American catfish, long-barbel catfish, man catfish, and stone catfish. The crustaceans may include crabs and shrimps (especially shrimps). The crabs may include freshwater crabs, soft-shell crabs, Asahi crabs, snow crabs, red snow crabs, Shanghai crabs, Mokuz crabs, Ishigani crabs, horseshoe crabs, hairy crabs, and Hanasaki crabs. The shrimps are not limited in size and may include so-called lobsters, prawns, and shrimps in the classification as food.

[0043] As the shrimp cultured in this embodiment, shrimps are preferred, and among the shrimps, the superfamily Penaeoidea is preferred. Among the superfamily Penaeoidea, the family Penaeidae is preferred. Examples of the shrimp of the family Penaeidae include those of the genera Farfantepenaeus, Fenneropenaeus, Litopenaeus, Marsupenaeus, Melicertus, Metapenaeopsis, Metapenaeus, Penaeus, Trachypenaeus, and Xiphopenaeus.

[0044] Among the Penaeidae cultured in this embodiment, for example, as edible shrimps, there are kuruma shrimp (Marsupenaeus japonicus), southern kuruma shrimp (Melicertus canaliculatus), tiger shrimp (Penaeus monodon), Chinese white shrimp (Penaeus chinensis), kuruma shrimp (Penaeus semisulcatus), broad-striped tiger shrimp (Penaeus latisulcatus), Indian white shrimp (Fenneropenaeus indicus), grass shrimp (Metapenaeus ensis), Tokara shrimp (Metapenaeus intermedius), Penaeus occidentalis, blue shrimp (Penaeus stylirostris), redtail shrimp (Penaeus pencicillatus), whiteleg shrimp (Litopenaeus vannamei), etc. However, the aquatic organisms are not limited to these.

[0045] The aquatic organisms cultured in this embodiment may include the family Penaeidae, the genus Litopenaeus, and particularly whiteleg shrimp (Litopenaeus vannamei). Whiteleg shrimp can be suitably used as the aquaculture target in this embodiment.

[0046] When culturing Pacific white shrimp as the aquatic organism cultured in this embodiment, the water temperature of the breeding water may be 25 to 32 °C, or may be 26 to 30 °C. Since the Pacific white shrimp is native to the tropics such as Central and South America, the above water temperature makes it a suitable temperature for breeding the Pacific white shrimp, and can further promote the growth of the Pacific white shrimp.

[0047] Referring to FIG. 1, the aquaculture facility for aquatic organisms according to an embodiment will be described. The aquaculture facility 100 includes a water tank 50 that stores breeding water for culturing aquatic organisms, an oxidant supply unit 200 that adds an oxidant to the breeding water W in the water tank 50, and information related to the bulking of the breeding water W and information related to the function of bioflocs. An information acquisition unit 150 that acquires at least one selected from the group consisting of The aquaculture facility 100 is configured to suppress the bulking of the breeding water W in the water tank 50 by the oxidant from the oxidant supply unit 200.

[0048] The oxidant supply unit 200 includes a tank 202 that stores the oxidant, an adjustment unit 203 that adjusts the supply amount of the oxidant to the water tank 50, and a control unit 205 that controls the adjustment unit 203. The information acquisition unit 150 may acquire at least one piece of information selected from the group consisting of SVI, FV, MLSS, mortality rate, concentration of ammonia nitrogen (TAN) in the breeding water, and concentration of nitrite nitrogen (NO2-N) in the breeding water. The information acquisition unit 150 may be, for example, a measuring device that directly measures these values, or a measuring device that measures values for calculating these values. The adjustment unit 203 adjusts the supply amount of the oxidant to the water tank 50 based on the information obtained by the information acquisition unit 150.

[0049] The adjusting unit 203 may adjust the supply amount of the oxidizing agent to the water tank so as to satisfy at least one selected from the group consisting of the above conditions (a), (b), and (c). By having the adjusting unit 203 that adjusts the supply amount of such an oxidizing agent, the occurrence of bulking in the aquaculture facility 100 can be sufficiently suppressed, and the death of aquatic organisms can be further suppressed. The adjusting unit 203 may adjust the supply amount of the oxidizing agent to the breeding water so that the above-described TAN concentration is 5.0 mg / mL or less and the NO2-N concentration is 30 mg / L or less.

[0050] The control unit 205 may be a computer that controls the adjusting unit 203. The control unit 205 is configured to be able to control the flow rate of the oxidizing agent supplied from the adjusting unit 203 to the water tank 50. The control unit 205 may include hardware such as, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output interface. The control unit 205 may output a control signal for controlling the adjusting unit 203 that adjusts the flow rate of the oxidizing agent or its dilution liquid. The adjusting unit 203 may be a normal flow rate adjustment valve.

[0051] It is not essential to automatically control the adjusting unit 203, and it may be manually adjusted. The addition of the oxidizing agent to the breeding water W may be performed by an operator using a flow meter or a metering container or the like. There may be a mixing unit upstream of the tank 202 that mixes the oxidizing agent and water to obtain a dilution liquid. Also, the oxidizing agent and water may be added to the tank 202 to prepare a dilution liquid. In this case, the tank 202 serves as the mixing unit. The water used for preparing the dilution liquid may be the breeding water in the water tank 50, or may be water different from this. Such water may be tap water.

[0052] Since tap water contains sodium hypochlorite for sterilization in advance, the tap water may be directly added from the oxidizing agent supply unit 200 to the breeding water W in the water tank 50. By using tap water, the handling of the oxidizing agent can be made more convenient. Also, the tap water used for cleaning the water tank 50 may be used as the dilution liquid.

[0053] The water tank 50 is provided with a partition member K configured such that the breeding water can flow in and out. The partition member K partitions a second part K2 into which the banana prawn P in the breeding water W cannot intrude and a first part K1 that is movable. The oxidizing agent is added to the second part K2 into which the banana prawn P cannot intrude. Therefore, it is possible to suppress direct contact between the oxidizing agent and the banana prawn P. In the first part K1, the oxidizing agent may not be detected. Thereby, damage to the banana prawn P caused by the oxidizing agent can be further suppressed. The partition member K may be, for example, a cage-like member or a plate-like member that partitions the first part K1 and the second part K2 so as to be arranged along the horizontal direction.

[0054] The volume of the second part K2 may be 0.5 to 10.0% with respect to the total volume of the breeding water W, may be 1.0 to 5.0%, or may be 1.5 to 3.0%. By the volume of the second part K2 being in such a range, while sufficiently securing the volume of the first part K1, it is possible to suppress a large amount of the oxidizing agent added to the second part K2 from flowing out into the first part K1.

[0055] The aquaculture facility 100 is a closed-type land-based aquaculture facility and can be used to culture the above-described aquatic organisms. The above-described method for culturing aquatic organisms can be carried out using the aquaculture facility 100. Therefore, the description content of the method for culturing aquatic organisms can also be applied to the aquaculture facility 100. The description content of the aquaculture facility 100 can also be applied to the method for culturing aquatic organisms.

[0056] Referring to FIGS. 2, 3 and 4, another example of an aquaculture facility will be described. As shown in FIG. 2, the aquaculture facility 105 has three water tanks 50. The water tanks 50 are arranged in the heat-insulating house 10 as shown in FIG. 3. The aquaculture facility 105 includes a boiler 30 for heating the breeding water W in the water tank 50 and a fuel tank 31 for storing the fuel used in the boiler 30. In the aquaculture facility 105, the boiler 30 is operated as needed to properly maintain the room temperature in the heat-insulating house 10 and the water temperature of the breeding water W in the water tank 50, while operating the air injector 60, the waterwheel 70, the aeration device 80, the circulation pump 91 and the automatic feeder 20, so that aquaculture of aquatic organisms can be carried out in the breeding water W in the water tank 50. The breeding water W in the water tank 50 may contain the biofloc described above. By the breeding water W containing biofloc, land-based aquaculture with reduced environmental load can be carried out.

[0057] Three water tanks 50 are arranged on the ground G of the portion covered by the heat-insulating house 10 shown in FIG. 3. In the present disclosure, the "heat-insulating house" is a structure for maintaining the temperature of the aquaculture water tank facility within a predetermined range. When the temperature outside the heat-insulating house is lower than the temperature suitable for aquaculture, the temperature inside the heat-insulating house can be maintained at a temperature suitable for aquaculture by isolating the heat-insulating house from the outside air. The heat-insulating house 10 is constructed by covering the periphery of a cattail-shaped building 11 formed by combining a plurality of pipe materials and angle materials with a synthetic resin film material 12. The heat-insulating house 10 may have a plurality of multi-span structures. The size and the number of multi-spans of the heat-insulating house 10 are not particularly limited.

[0058] As shown in FIG. 3, the upper surface and the outer peripheral surface of the water tank 50 are covered with a plurality of plate-shaped heat insulating materials 40 (for example, foamed synthetic resin materials). Above the water tank 50, a plurality of heat insulating materials 40 are detachably arranged on a plurality of receiving beams 41 horizontally supported by the constituent members of the building 11. The heat insulating material 40 has a heat insulating function and may also have a function of shielding external light (sunlight). When cultivating banana prawns in the water tank 50, it is preferable to keep the temperature of the breeding water W relatively high (about 28°C). Since the upper surface of the water tank 50 is covered with the heat insulating material 40 and the entire water tank 50 is arranged in the heat preservation house 10, the dissipation of the breeding water W can be suppressed. Since the change in the water temperature of the breeding water W in the water tank 50 is suppressed by the heat insulating material 40, the light and heat cost can be reduced.

[0059] The plan view shape of the water tank 50 is rectangular, and the inner wall surfaces 51 on the short side and 52 on the long side of the rectangle constituting the water tank 50 may be inclined so as to form a downward gradient toward the inside of the water tank 50.

[0060] In the aquaculture facility 105, the water tank 50 is formed by forming a concave portion in the direction of gravity from the ground G and laying a water-repellent synthetic resin sheet on the inner wall surface and the bottom surface of the concave portion. The plan view shape of the bottom surface 53 of the water tank 50 is rectangular and may be generally horizontal.

[0061] The aquaculture facility 105 is provided with the water tank 50 by laying a synthetic resin sheet material (for example, a PE protection sheet) in a concave portion formed on the ground G. Instead of the water tank 50, a water tank made of concrete, plastic, or metal may be used.

[0062] As shown in FIGS. 2, 3, and 4, a flat partition wall 54 is provided at the central portion of the water tank 50 along the longitudinal direction of the water tank 50. The partition wall 54 and its end portion 54a are separated from the four inner wall surfaces 51, 51, 52, 52. A circulating water channel 55 is formed around the partition wall 54 through which the water flow S of the breeding water W flows horizontally by the four inner wall surfaces 51, 51, 52, 52 and the partition wall 54.

[0063] On the bottom surface 53 of the water tank 50, a plurality of air injectors 60 are arranged along the longitudinal direction of the circulating water channel 55. Near the longitudinal ends of the water tank 50, a pair of water wheels 70, 70 are arranged with a partition wall 54 therebetween. Near the longitudinal ends of the water tank 50, aeration devices 80 are arranged respectively. Outside the short side portions of the water tank 50, a sedimentation tank 90 and a circulation pump 91 are arranged respectively. Outside one of the short side portions of the water tank 50, an automatic feeder 20 and a circulation pump 91 are arranged.

[0064] As shown in FIGS. 2 and 4, the water wheel 70 includes a rotating blade 71 that can rotate about a horizontal axis and a motor 72 for driving the rotating blade 71. The rotation direction of the rotating blade 71 can be switched. By ejecting water mixed with air from a plurality of air injectors 60 provided on the bottom surface 53 of the water tank 50, a water flow S that continuously swirls and circulates around the partition wall 54 as shown by the arrow lines in FIGS. 2 and 4 can be generated in the breeding water W in the water tank 50. The water tank 50 is suitable for culturing aquatic organisms (for example, Kuruma shrimp, bovine shrimp, button shrimp, grape shrimp, long-arm shrimp, cherry shrimp, red cherry shrimp, Kourai shrimp, reed shrimp, banana prawn) having the property of swimming along the water flow S.

[0065] In the water tank 50, by operating the aeration device 80 and the plurality of water wheels 70, oxygen in the air can be efficiently supplied into the breeding water W. The rotation direction of the rotating blade 71 of the water wheel 70 may be changeable.

[0066] The aquaculture facility 105 includes an oxidant supply unit 200 that adds an oxidant to the water tank 50. The oxidant supply unit 200 may be arranged outside the water tank 50. The oxidant supply unit 200 may be configured to add an oxidant to the breeding water W in the water tank 50, or may be configured to add an oxidant or a diluted solution thereof into the water of the breeding water W. The aquaculture facility 105 provided with the oxidant supply unit 200 can sterilize filamentous bacteria in the breeding water W and suppress the bulking of the breeding water W. Such an aquaculture facility 100 can suppress the death of aquatic organisms and stably perform the aquaculture of aquatic organisms.

[0067] Similar to FIG. 1, the oxidant supply unit 200 may include an adjustment unit that adjusts the supply amount of the oxidant based on information related to the bulking of the breeding water W, and a control unit that controls the adjustment unit. Based on each piece of information, the adjustment unit can adjust the supply amount of the oxidant. Such aquaculture equipment 105 can add an oxidant when bulking begins to occur in the breeding water, and can maintain a favorable water quality in which bulking is suppressed.

[0068] The above-described method for culturing aquatic organisms can be performed using the aquaculture equipment 100 and 105. Therefore, the description content of the method for culturing aquatic organisms is also applicable to the aquaculture equipment 100 and 105. The description content of the aquaculture equipment 100 and 105 is also applicable to the method for culturing aquatic organisms.

[0069] A method for transferring breeding water according to an embodiment is a method for transferring breeding water containing bioflocs, and includes a step of obtaining breeding water for transfer in which bulking is suppressed by adding an oxidant to the breeding water used in a first water tank for culturing aquatic organisms, and a step of transferring the breeding water for transfer to a second water tank for culturing aquatic organisms. Transferring refers to the operation of transferring the breeding water in the water tank to another water tank. For the transfer, a part of the breeding water in the first water tank may be transferred to the second water tank, or all of the breeding water in the first water tank may be transferred to the second water tank. Also, it may be transferred from one first water tank to a plurality of second water tanks. By having such steps, the breeding water after adding the oxidant can be transferred from the first water tank to the second water tank. Thereby, the breeding water containing bioflocs with suppressed bulking can be transferred from the first water tank to the second water tank, and the bioflocs effective for aquaculture can be reused in the second water tank.

[0070] As described above, several embodiments of the present disclosure have been described, but the present disclosure is not limited to the above embodiments in any way.

[0071] The present disclosure includes the following embodiments. [1] A method for culturing aquatic organisms in breeding water in a water tank, A method for culturing aquatic organisms, comprising a step of adding an oxidizing agent to the breeding water to suppress bulking of the breeding water. [2] The method for culturing aquatic organisms according to [1], wherein the breeding water contains biofloc. [3] The method for culturing aquatic organisms according to [2], comprising a step of adjusting the supply amount of the oxidizing agent to the water tank based on at least one selected from the group consisting of information related to bulking of the breeding water and information related to the function of the biofloc. [4] When the floc volume of the biofloc is FV (mL), the floc dry weight is TSS (mg), and the volume per gram of the floc calculated by FV / TSS×1000 is SVI (mL / g), the method for culturing aquatic organisms according to [2] or [3], comprising a step of adjusting the supply amount of the oxidizing agent to the water tank so as to satisfy at least one selected from the group consisting of the following conditions (a), (b), and (c). (a) SVI≦1211 mL / g (b) FV≦350 mL (c) The mortality rate of the aquatic organisms≦0.59% [5] The method for culturing aquatic organisms according to any one of [1] to [4], comprising a step of adjusting the supply amount of the oxidizing agent to the breeding water so that the concentration of ammonia nitrogen in the breeding water in the water tank is 5.0 mg / L or less and the concentration of nitrite nitrogen is 30 mg / L or less. [6] The method for culturing aquatic organisms according to any one of [1] to [5], wherein the oxidizing agent contains sodium hypochlorite. [7] comprising a step of mixing water and an oxidizing agent to obtain a dilution of the oxidizing agent, In the step of suppressing bulking, the dilution is mixed with the breeding water in the water tank. The method for culturing aquatic organisms according to any one of [1] to [6]. [8] In the breeding water of the water tank, a first part where the aquatic organisms can move and a second part where they cannot enter are provided. In the step of suppressing bulking, the oxidizing agent is added to the second part. The method for culturing aquatic organisms according to any one of [1] to [7]. [9] The method for culturing aquatic organisms according to any one of [1] to [8], wherein the aquatic organisms include Litopenaeus vannamei.

[10] An aquaculture facility for aquatic organisms, comprising: a water tank for storing breeding water for culturing aquatic organisms; and an oxidant supply unit for adding an oxidant to the breeding water, The aquaculture facility for aquatic organisms, which is configured to suppress bulking of the breeding water in the water tank by the oxidant.

[11] The aquaculture facility for aquatic organisms according to

[10] , wherein the breeding water contains biofloc.

[12] The aquaculture facility for aquatic organisms according to

[11] , wherein the oxidant supply unit has an adjustment unit for adjusting the supply amount of the oxidant to the water tank based on at least one selected from the group consisting of information related to bulking of the breeding water and information related to the function of the biofloc.

[13] When the floc volume of the biofloc is FV (mL), the floc dry weight is TSS (mg), and the volume per gram of the floc calculated by FV / TSS×1000 is SVI (mL / g), the aquaculture facility for aquatic organisms according to

[11] or

[12] , which is provided with an adjustment unit for adjusting the supply amount of the oxidant from the oxidant supply unit so as to satisfy at least one selected from the group consisting of the following conditions (a), (b), and (c). (a) SVI≦1211 mL / g (b) FV≦350 mL (c) The mortality rate of the aquatic organisms≦0.59%

[14] An aquaculture facility for aquatic organisms according to any one of

[10] to

[13] , which is provided with a mixing unit for mixing water and an oxidant to obtain a dilution of the oxidant, and the dilution is mixed with the breeding water in the water tank.

[15] An aquaculture facility for aquatic organisms according to any one of

[10] to

[14] , which is provided with a partitioning member for providing a first part in the breeding water of the water tank where the aquatic organisms can move and a second part where they cannot enter, and the oxidant supply unit adds the oxidant to the second part.

[16] A method for transplanting breeding water containing biofloc, A step of adding an oxidizing agent to the breeding water in the first water tank to obtain breeding water for transplantation with bulking suppressed; A method for transplanting breeding water, comprising a step of transplanting the breeding water for transplantation into a second water tank for culturing aquatic organisms.

Example

[0072] Hereinafter, the content of the present disclosure will be described more specifically with reference to examples, comparative examples, and reference examples. It should be noted that the present disclosure is not limited to the following examples.

[0073] <Relationship between bulking and the number of dead individuals> (Comparative Example 1) Rearing was started for 184,998 juvenile shrimps with a body weight of less than 1 g of Litopenaeus vannamei in a water tank with 435 t of breeding water containing 52.2 kg of biofloc (TSS). The water temperature was maintained at 26 - 32°C, and a carbon source was added for ammonia concentration control, and a pH adjuster was added for pH maintenance to promote the formation of biofloc and perform adjustments. Oxygen supply was carried out to maintain an aerobic environment, and excess biofloc was recovered to maintain an appropriate amount of biofloc. From the start of rearing, TSS, FV, SVI, the number of dead individuals per day, and the mortality rate per day were determined. The number of dead individuals per day was determined by visually observing the water tank every day and counting the number of dead individuals. The mortality rate per day was determined as the ratio of the estimated number of surviving individuals on the measurement day to the number of dead individuals on the measurement day. The estimated number of surviving individuals on the measurement day was determined by subtracting the cumulative number of dead individuals from the day before the measurement day from the number of individuals introduced into the water tank. To accurately judge the effect of reducing the mortality rate by suppressing bulking, the mortality rate was determined as the average of the mortality rates per day measured on the target day and the days before and after it. FV was determined by collecting 1 L of breeding water into a graduated cylinder, allowing it to stand for 30 minutes, and reading the volume of the biofloc. TSS was determined by drying the biofloc for which FV was measured and measuring its weight. SVI was calculated from FV and TSS. The measurement results of the mortality rate, TSS, FV, and SVI from 20 to 63 days after the start of rearing are shown in Table 1. The columns where measurements were not performed are indicated by "-".

[0074] [Table 1]

[0075] As shown in Table 1, the mortality rate of white-leaf shrimp tended to increase as the FV and SVI, which are indicators of bulking, increased. Therefore, it was confirmed that bulking affects the mortality rate of white-leaf shrimp.

[0076] <Experiment on cultivating aquatic organisms using oxidizing agents> (Example) Biofloc culture of white shrimp was carried out using an aquarium equipped with a partition member as shown in FIG. 1. Three tons of breeding water containing 10 L of biofloc was stored in the aquarium, and 789 white shrimp weighing about 20 g were placed in the aquarium to start breeding. Feeding was carried out by giving 200 g of feed every morning and afternoon. The water temperature was maintained at about 28°C, and was adjusted by adding a pH adjuster to maintain the pH. Oxygen was supplied to maintain an aerobic environment. The number of dead tails, mortality rate, water temperature, dissolved oxygen (DO), TAN, NO2-N, pH, MLSS, TSS, FV, and SVI were measured every day after the start of breeding to investigate changes in water quality. The mortality rate, MLSS, TSS, FV, and SVI were determined using the same procedure as in Comparative Example 1. DO was measured using a commercially available dissolved oxygen meter (manufactured by Iijima Electronics Co., Ltd., product name: DO Meter ID-150), and pH was measured using a commercially available pH meter (manufactured by Toko Chemical Laboratory, product name: Glass Electrode Type Hydrogen Ion Concentration Indicator TPX-999i). TAN and NO2-N were measured using commercially available Pack Tests (manufactured by Kyoritsu Chemical Laboratory, product names: Pack Test Ammonium, Pack Test Nitrite).

[0077] The measurement results of the mortality rate, MLSS, TSS, FV, and SVI for 87 to 102 days after the start of rearing are shown in Table 2. The measurement results of the mortality rate, water temperature, DO, TAN, NO2-N, and pH for 87 to 102 days after the start of rearing are shown in Table 3.

[0078] After the start of breeding, there was no mortality of Litopenaeus vannamei during the 1 to 69 days, and no balling occurred. During this period, FV was 25 or less, and SVI was 60 or less, and no change in water quality was detected. Mortality of Litopenaeus vannamei was observed on the 70th day after the start of breeding. After the 70th day, the number of dead individuals gradually increased. Thereafter, FV and SVI tended to increase with the increase in the number of dead individuals. When the dead individuals were visually confirmed, solids were found to be clogged in the gills. From these results, it was found that balling had occurred.

[0079] On the 91st day after the start of breeding, 250 mL of an aqueous sodium hypochlorite solution was added to the second part of the breeding water partitioned by a cage-like member at a supply rate of 100 mL / h. The partitioning member was a cage-like member, and the volume of the second part was 1.75% of the total volume of the breeding water. The concentration of sodium hypochlorite in the aqueous sodium hypochlorite solution added at this time was 2.4% by mass. The FV at the start of addition was 600 mL / g. The addition was carried out over 4 hours. Two hours after the start of addition, FV had decreased to 400 mL / g. Therefore, it was confirmed that the addition of the aqueous sodium hypochlorite solution decreased FV and suppressed balling. In addition, no chlorine was detected in the first compartment where Litopenaeus vannamei could move (detection limit of chlorine: 0.05 mass ppm).

[0080] On the 98th day after the start of breeding, 200 mL of an aqueous sodium hypochlorite solution was added to the above-mentioned second part at a supply rate of 50 mL / h. The concentration of sodium hypochlorite in the aqueous sodium hypochlorite solution added at this time was 6.0% by mass. The FV at the start of addition was 350 mL / g. The addition was carried out over 4.5 hours. Four and a half hours after the start of addition, FV had decreased to 15 mL / g. Therefore, it was confirmed that the addition of the aqueous sodium hypochlorite solution decreased FV and suppressed balling. In addition, no chlorine was detected in the first part where Litopenaeus vannamei could move (detection limit of chlorine: 0.05 mass ppm).

[0081] On the 91st day after the start of breeding, when 250 mL of an aqueous sodium hypochlorite solution with a concentration of 2.4% by mass was added, the SVI, which was 1771 mL / g on the 91st day, decreased to 613 mL / g on the 92nd day, and furthermore, the mortality rate also decreased from 2.3% to 1.1%. Thereafter, as the number of breeding days passed, the SVI began to rise again. Therefore, on the 98th day after the start of breeding, when 200 mL of an aqueous sodium hypochlorite solution with a concentration of 6.0% by mass was added, the SVI, which was 1211 mL / g on the 98th day, decreased to 66 mL / g on the 99th day, and furthermore, the mortality rate also decreased from 0.59% to 0.47%. Since sodium hypochlorite was added on the 91st day and the 98th day, an "〇" was marked in the columns for the 91st day and the 98th day in the item of sodium hypochlorite dropping in Table 2.

[0082] Also, the values of TAN and NO2-N did not increase during the breeding period, and it was confirmed that the function of nitrifying bacteria in the biofloc was maintained even when sodium hypochlorite was added. From the above, it was shown that adding sodium hypochlorite to the breeding water sterilizes the filamentous bacteria that cause bulking and suppresses bulking, while having little effect on nitrifying bacteria.

[0083]

Table 2

[0084]

Table 3

Industrial Applicability

[0085] The present disclosure can provide a cultivation method and cultivation equipment capable of stably cultivating aquatic organisms. In addition, a method for transplanting breeding water capable of efficiently cultivating aquatic organisms can be provided.

Explanation of Signs

[0086] 100, 105... Aquaculture equipment, W... Rearing water, 50... Water tank, 200... Oxidizing agent supply section, 202... Tank, 203... Adjusting section, 205... Control section, 150... Information acquisition section, 10... Insulated house, 20... Automatic feeder, 30... Boiler, 31... Fuel tank, 51, 52... Inner wall surface, 53... Bottom surface, 54... Partition, 54a... End, 55... Circulating water channel, 60... Air injector, 70... Waterwheel, 71... Rotating blades, 72... Motor, 80... Aeration device, 90... Sedimentation tank, 91... Circulation pump, G... Ground, 11... Building, 12... Synthetic resin film material, 40... Heat insulation material, 41... Support beam, K... Partition member, K1... First part, K2... Second part, P... Banana prawn, S... Water flow.

Claims

1. A method for culturing aquatic organisms in breeding water in a water tank, comprising: a step of adding an oxidizing agent to the breeding water to suppress bulking of the breeding water.

2. The method for culturing aquatic organisms according to claim 1, wherein the breeding water contains biofloc.

3. The method for culturing aquatic organisms according to claim 2, further comprising a step of adjusting the supply amount of the oxidizing agent to the water tank based on at least one selected from the group consisting of information related to bulking of the breeding water and information related to the function of the biofloc.

4. When the floc volume of the biofloc is FV (mL), the floc dry weight is TSS (mg), and the volume per gram of floc calculated by FV / TSS×1000 is SVI (mL / g), the method for culturing aquatic organisms according to claim 2, further comprising a step of adjusting the supply amount of the oxidizing agent to the water tank so as to satisfy at least one selected from the group consisting of the following conditions (a), (b), and (c). (a) SVI≦1211 mL / g (b) FV≦350 mL (c) The mortality rate of the aquatic organisms≦0.59%

5. The method for culturing aquatic organisms according to any one of claims 1 to 4, further comprising a step of adjusting the supply amount of the oxidizing agent to the breeding water so that the concentration of ammonia nitrogen in the breeding water in the water tank is 5.0 mg / L or less and the concentration of nitrite nitrogen is 30 mg / L or less.

6. The method for culturing aquatic organisms according to any one of claims 1 to 4, wherein the oxidizing agent contains sodium hypochlorite.

7. A step of mixing water and an oxidizing agent to obtain a dilution of the oxidizing agent, wherein, in the step of suppressing bulking, the dilution is mixed with the breeding water in the water tank.

8. In the breeding water of the water tank, a first part where the aquatic organisms can move and a second part where they cannot enter are provided, wherein, in the step of suppressing bulking, the oxidizing agent is added to the second part.

9. The method for culturing aquatic organisms according to any one of claims 1 to 4, wherein the aquatic organisms include Pacific white shrimp.

10. An aquaculture facility for aquatic organisms, comprising a water tank for containing breeding water for culturing aquatic organisms and an oxidizing agent supply unit for adding an oxidizing agent to the breeding water. An aquaculture facility for aquatic organisms configured to suppress bulking of the breeding water in the water tank by the oxidizing agent.

11. The aquaculture facility for aquatic organisms according to claim 10, wherein the breeding water contains biofloc.

12. The oxidant supply unit has an adjustment unit that adjusts the supply amount of the oxidant to the water tank based on at least one selected from the group consisting of information related to bulking of the breeding water and information related to the function of the biofloc. The aquaculture facility for aquatic organisms according to claim 11.

13. When the oxidant supply unit sets the floc volume of the biofloc as FV (mL), the floc dry weight as TSS (mg), and the volume per gram of floc calculated by FV / TSS×1000 as SVI (mL / g), it has an adjustment unit that adjusts the supply amount of the oxidant so as to satisfy at least one selected from the group consisting of the following conditions (a), (b), and (c). The aquaculture facility for aquatic organisms according to claim 11. (a) SVI≦1211 mL / g (b) FV≦350 mL (c) The mortality rate of the aquatic organisms≦0.59%

14. It is provided with a mixing unit that mixes water and an oxidizing agent to obtain a diluted solution of the oxidizing agent. In the breeding water in the water tank, the diluted solution is mixed. The aquaculture facility for aquatic organisms according to any one of claims 10 to 13.

15. It is provided with a partitioning member that provides a first part where the aquatic organisms can move and a second part where they cannot enter in the breeding water of the water tank. The oxidant supply unit adds the oxidizing agent to the second part. The aquaculture facility for aquatic organisms according to any one of claims 10 to 13.

16. A method for transplanting breeding water containing biofloc, comprising: A step of adding an oxidizing agent to the breeding water in the first water tank to obtain breeding water for transplantation with bulking suppressed; A step of transplanting the breeding water for transplantation into a second water tank for culturing aquatic organisms. A method for transplanting breeding water.

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