Aquaculture system and aquaculture method

Abstract

An aquaculture system 1 comprises: a waterproof sheet H that forms an aquaculture farm A; an upper fish net NU that is provided on the upper side of the waterproof sheet H; first floats F1 that are provided to the upper end of the waterproof sheet H so as to be positioned at the sea surface during low tide; second floats F2 that are provided to the upper fish net NU so as to be positioned at the sea surface during high tide; ropes for connecting the first floats F1 and anchors provided on the seabed; and control devices 10. The control devices 10 control the lengths of the ropes L between connections to the anchors K and connections to the first floats F1 so as to allow seawater to flow into the aquaculture farm A from portions between the first floats F1 and the second floats F2 during high tide.

Description

Aquaculture system and aquaculture method

[0001] The present disclosure relates to an aquaculture system and a method.

[0002] In marine aquaculture, water quality deterioration due to excrement or leftover food from the cultured organisms, such as fish and crustaceans, is a problem. For example, red tides or hypoxic water masses caused by eutrophication can have a negative impact on marine organisms (Non-Patent Documents 1 and 2).

[0003] One example is the open-water IMTA (integrated multi-trophic aquaculture) system (Non-Patent Document 3). In this system, leftover feed or waste from the cultured organisms is recycled as nutrients, and organisms of different trophic levels are simultaneously cultivated. In general, in integrated aquaculture, the cultivation of fish or shrimp and seaweed is carried out simultaneously in separate areas (Non-Patent Document 4). Integrated aquaculture is attracting attention as a sustainable method of marine aquaculture aimed at reducing environmental pollution.

[0004] Akifumi Nishimura, "The effect of organic pollution in fish farms on the proliferation of red tide organisms Gymnodinium type-'65 and Chattonella antiqua," [online], June 1982, Plankton Society of Japan, Journal of the Plankton Society of Japan, Vol. 29, No. 1, pp. 1-7, [Retrieved July 16, 2024], Internet <URL: https: / / agriknowledge.affrc.go.jp / RN / 2030254410.pdf> Katsutoshi Ito, Mana Ito, and Ryuhei Nakamura, "Real-time monitoring of the bottom sediment environment in aquaculture farms," ​​[online], May 27, 2021, Aquaculture Business 59.3 (2022): 28-31, [Retrieved July 16, 2024], Internet <URL: https: / / www.spf.org / global-data / opri / 20210527_OceanForum181_4.pdf> Barrington, Kelly, Thierry Chopin, and Shawn Robinson, "Integrated multi-trophic aquaculture (IMTA) in marine temperate waters", [online], Integrated mariculture: a global review. FAO Fisheries and Aquaculture Technical Paper 529 (2009): 7-46, [Retrieved July 16, 2024], Internet <URL: https: / / www.vliz.be / imisdocs / publications / ocrd / 212056.pdf> Shpigel, M., et al. "The sea urchin, Paracentrotus lividus, in an Integrated Multi-Trophic Aquaculture (IMTA) system with fish (Sparus aurata) and seaweed (Ulva lactuca): Nitrogen partitioning and proportional configurations." Aquaculture 490 (2018): 260-269.

[0005] Marine aquaculture farms are typically conducted by separating the water surface with nets. The area separated from the sea is called a fish cage. Seawater is constantly exchanged between the fish cage and the sea in accordance with the ocean currents, which creates the problem of being unable to control the amount of seawater being exchanged.

[0006] The lack of control over the amount of seawater exchange can have the following effects:

[0007] Even if oxygen is produced by seaweed in integrated aquaculture, a certain percentage of the produced oxygen is released into the sea rather than flowing into the cages of the cultured organisms. Therefore, seawater exchange may not improve the growth environment of the cultured organisms.

[0008] The present disclosure has been made in consideration of the above circumstances, and the purpose of the present disclosure is to provide a technology that can control the amount of seawater exchanged into a marine aquaculture farm.

[0009] An aquaculture system according to one embodiment of the present disclosure comprises a waterproof sheet forming an aquaculture area, an upper fishing net attached to the upper side of the waterproof sheet, a first float attached to the upper end of the waterproof sheet and positioned above the sea surface at low tide, a second float attached to the upper fishing net and positioned above the sea surface at high tide, a rope connecting the first float to an anchor attached to the seabed, and a control device that controls the length of the rope between the connection part with the anchor and the connection part with the first float so that seawater flows into the aquaculture area between the first float and the second float at high tide.

[0010] An aquaculture method according to one embodiment of the present disclosure is used in an aquaculture system comprising: a waterproof sheet forming an aquaculture farm; an upper fishing net attached to the upper side of the waterproof sheet; a first float attached to the upper end of the waterproof sheet and positioned above the sea surface at low tide; a second float attached to the upper fishing net and positioned above the sea surface at high tide; a rope connecting the first float to an anchor attached to the seabed; and a control device that controls the length of the rope between the connection part with the anchor and the connection part with the first float so that seawater flows into the aquaculture farm from between the first float and the second float at high tide. The control device obtains the exchange amount of seawater flowing into the aquaculture farm, calculates the length of the rope between the connection part with the anchor and the connection part with the first float so that the acquired amount of seawater will flow into the aquaculture farm from between the first float and the second float at high tide, and changes the length of the rope between the connection part with the anchor and the connection part with the first float to the calculated length.

[0011] According to the present disclosure, a technology can be provided that can control the amount of seawater exchanged into a marine aquaculture farm.

[0012] FIG. 1 is a diagram illustrating an aquaculture system according to the present disclosure. FIG. 2 is a diagram illustrating the relationship between the aquaculture system according to the present disclosure and the water level. FIG. 3 is a diagram illustrating definitions for explaining a design example of the aquaculture system according to the present disclosure. FIG. 4 is a diagram illustrating an aquaculture system according to a modified example. FIG. 5 is a diagram illustrating the relationship between the aquaculture system according to the modified example and the water level. FIG. 6 is a diagram illustrating definitions for explaining a design example of the aquaculture system according to the modified example. FIG. 7 is a diagram illustrating a control device used in the aquaculture system according to the present disclosure. FIG. 8 is a diagram illustrating the relationship between the water level at high tide and the length of the rope in the aquaculture system according to the present disclosure. FIG. 9 is a flowchart illustrating an aquaculture method used in the aquaculture system according to the present disclosure. FIG. 10 is a flowchart for controlling the length of the rope to exchange the same amount of seawater in the aquaculture system according to the present disclosure. FIG. 11 is a diagram illustrating the hardware configuration of a computer used in the control device.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same parts are designated by the same reference numerals and the description thereof will be omitted.

[0014] (Aquaculture System) In the aquaculture system 1 according to the present disclosure, the fish farm refers to a fish pen or aquaculture pond where fish, shrimp, etc. are enclosed and cultivated. Unless otherwise specified, the directions shown in this disclosure refer to the direction when the aquaculture system is installed in the sea. In this disclosure, the inflow and outflow of seawater refer to the exchange of seawater as controlled by the aquaculture system 1, and do not include accidental inflow and outflow due to natural phenomena such as wind or waves.

[0015] The aquaculture system 1 according to the present disclosure exchanges seawater inside and outside the aquaculture farm by utilizing the difference in sea level caused by the tides. In the aquaculture system 1 shown in Fig. 1, the aquaculture farm A is a floating aquaculture cage separated from the sea. As shown in Fig. 2, at high tide, the upper fishing net NU is exposed above the waterproof sheet H surrounding the aquaculture farm A, and the lower fishing net ND is exposed below the waterproof sheet H. Seawater flows into the aquaculture farm A from above and flows out from below.

[0016] This allows the aquaculture system 1 to exchange seawater within the farm with seawater from outside. In particular, in the case of integrated aquaculture, the dissolved oxygen concentration of oxygen produced by seaweed is highest near the sea surface. In the aquaculture system 1, the inflow of seawater around high tide enables oxygen to be supplied to the cultured organisms. As seawater within farm A flows out from the bottom of farm A, aquaculture wastewater flows out to the outside. In the case of integrated aquaculture, the discharged aquaculture wastewater is supplied to the seaweed farm.

[0017] Here, the aquaculture system 1 allows for a desired amount of seawater exchange by controlling the vertical width of the upper fishing net NU that is exposed at high tide.

[0018] An aquaculture system 1 according to the present disclosure will be described with reference to Figure 1. Figure 1 shows the aquaculture system 1 installed in the sea at low tide.

[0019] The aquaculture system 1 includes a waterproof sheet H, an upper fishing net NU, a first float F1, a second float F2, a rope L, a first weight W1, a second weight W2, and a control device 10.

[0020] The waterproof sheet H forms the farm A. In the present disclosure, the farm A is formed by enclosing a part of the sea with the waterproof sheet H. The upper end of the waterproof sheet H is located on the sea surface at low tide and is located underwater at high tide. The waterproof sheet H covers the bottom of the farm A at low tide and opens the bottom at high tide.

[0021] The upper fishing net NU is provided above the waterproof sheet H. Since the upper end of the waterproof sheet H is located above the sea surface at low tide, the upper fishing net NU connected to the upper end of the waterproof sheet H floats on the sea surface.

[0022] The first float F1 is attached to the upper end of the waterproof sheet H and is located above the sea surface at low tide. The second float F2 is attached to the upper fishing net and is located above the sea surface at high tide.

[0023] The rope L connects the first float F1 to an anchor K provided on the seabed.

[0024] The first weight W1 and the second weight W2 are provided below the waterproof sheet H. The first weight W1 and the second weight W2 are provided to fix the waterproof sheet H in a predetermined position and form the fish farm A. The first weight W1 is provided at the bottom end of the waterproof sheet H. The first weight W1 is provided near the center of the bottom of the fish farm A, together with the first weight W1 provided at the bottom end of the waterproof sheet H extending from the other direction. The second weight W2 is provided in the middle of the waterproof sheet H. The second weight W2 is a weight to form the edge of the bottom of the fish farm A.

[0025] The control device 10 controls the length of the rope L between the connection part with the anchor K and the connection part with the first float F1 so that seawater flows into the aquaculture farm A from between the first float F1 and the second float F2 at high tide. In this disclosure, a case where the control device 10 adjusts the position of the rope L connected to the first float F1 will be described, but this is not limited to this.

[0026] The relationship between the aquaculture system 1 and the water level will be described with reference to Figure 2. Figure 2 shows, from left to right, the aquaculture system 1 in a state C1 at low tide, a state C2 during the transition from low tide to high tide, and a state C3 at high tide. At high tide, the length of the rope L between the connection part with the anchor K and the connection part with the first float F1 is adjusted so that the slack in the rope L increases, the first float F1 sinks in the sea, and a predetermined amount of seawater flows in.

[0027] In state C1, the first float F1, the second float F2, and the upper fishing net NU are located on the sea surface. The upper end of the waterproof sheet H is located on the sea surface, and seawater does not flow into the waterproof sheet H. Since the first weight W1 is located on the bottom of the fish farm A, the lower fishing net ND is not exposed to the sea. The rope L has more slack than in states C2 and C3.

[0028] In state C2, the aquaculture system 1 rises as the water level rises. Compared to state C1, the slack in the rope L is reduced, but the aquaculture system 1 is in a similar state to state C1.

[0029] In state C3, as the water level rises, the first float F1 lifts up the waterproof sheet H, but because the rope L is locked in a stretched position, the first float F1 remains in the sea and the second float F2 is positioned at the sea surface. As a result, seawater flows into the aquaculture facility A from between the first float F1 and the second float F2. Because the upper fishing net NU is provided between the first float F1 and the second float F2, the target aquaculture organisms in the aquaculture facility A do not flow out of the aquaculture facility A.

[0030] Furthermore, in state C3, as the farm A rises and seawater flows in at the top of the farm A, the first weight W1 drops relative to the lower fishing net ND, the waterproof sheet H opens, and the lower fishing net ND is exposed to the sea at the bottom of the farm A. This causes seawater inside the farm A to flow out of the farm A. Because the lower fishing net ND is installed on the bottom of the farm A, the cultured organisms in the farm A do not flow out of the farm A.

[0031] Here, by adjusting the length of the rope L between the connection part with the anchor K and the connection part with the first float F1, the distance between the first float F1 and the second float F2 at high tide can be adjusted. This allows the aquaculture system 1 to control the amount of seawater flowing into the aquaculture site A.

[0032] A design example of the aquaculture system 1 according to the present disclosure is shown in Equation (1). ｓ１ and the length of the bottom of the waterproof sheet * 1 / 2 L ｓ２ is as shown in FIG.

[0033]

[0034] As shown in formula (1), the amount of seawater flowing into the aquaculture farm A per unit time at high tide is determined by the depth of the first float F1 from the sea surface. According to formula (1), the length L of the rope L between the connection part with the anchor K and the connection part with the first float F1 is determined by taking into account the water level at high tide and the amount of seawater flowing in at high tide specified by the user, etc. Ａ is calculated.

[0035] The formula (1) is merely an example and is not limiting. It may be modified as appropriate depending on the shape of the farm A.

[0036] (Modification) An aquaculture system 1a according to a modification will be described with reference to Fig. 4. In the aquaculture system 1a shown in Fig. 4, the aquaculture site A is an aquaculture pond formed by separating the edge of the sea with a waterproof sheet H. The aquaculture site A is formed by utilizing existing structures such as a quay, a bank, and the seabed.

[0037] In the aquaculture system 1a according to the modified example, as in the aquaculture system 1 according to the present disclosure, at high tide, the upper fishing net NU is exposed above the waterproof sheet H surrounding the aquaculture site A, and the lower fishing net ND is exposed below the waterproof sheet H. Seawater flows into the aquaculture site A from above and flows out from below. In the aquaculture system 1a, by controlling the width of the upper fishing net NU that is exposed at high tide, the desired amount of seawater exchange is possible.

[0038] In this modification, the vertical length of the waterproof sheet H is longer than the distance from the sea surface to the seabed at low tide and shorter than the distance from the sea surface to the seabed at high tide. This allows the waterproof sheet H to prevent seawater from flowing into the aquaculture site A at low tide and to allow seawater to flow into the aquaculture site A at high tide.

[0039] At high tide, the farm A forms an opening on the underside of the waterproof sheet H. This prevents seawater from flowing out of the farm A into the sea at low tide and allows seawater to flow out of the farm A into the sea at high tide.

[0040] The relationship between the aquaculture system 1a and the water level will be described with reference to Figure 5. Figure 5 shows, from left to right, the aquaculture system 1 in a state C1 at low tide, a state C2 during the transition from low tide to high tide, and a state C3 at high tide. At high tide, the length of the rope L between the connection with the anchor K and the connection with the first float F1 is adjusted so that the slack in the rope L increases, the first float F1 sinks in the sea, and a predetermined amount of seawater flows in.

[0041] In state C1, the first float F1, the second float F2, and the upper fishing net NU are located on the sea surface. The vertical length of the waterproof sheet H matches the height of the fish farm A. The upper end of the waterproof sheet H is located above the sea surface outside the fish farm A, so seawater does not flow into the waterproof sheet H. The lower end of the waterproof sheet H and the weight W attached to the lower fishing net ND are located on the seabed, so the lower fishing net ND is located on the seabed. The rope L is slack, similar to state C2, but is more slack than state C3.

[0042] In state C2, even if the water level outside farm A rises, seawater will not flow into farm A as long as the sea level does not exceed the top edge of waterproof sheet H. Since the vertical length of waterproof sheet H matches the height of farm A, rope L is loose, similar to state C1, but is looser than state C3.

[0043] In state C3, in the aquaculture system 1a, as the water level outside the aquaculture farm A rises, the first float F1 lifts up the waterproof sheet H, but because the rope L is locked in a stretched position, the first float F1 remains in the sea and the second float F2 is located at the sea surface. As a result, seawater flows into the aquaculture farm A from between the first float F1 and the second float F2. Because the upper fishing net NU is provided between the first float F1 and the second float F2, the target aquaculture organisms in the aquaculture farm A do not flow out of the aquaculture farm A.

[0044] Furthermore, in state C3, as the waterproof sheet H rises, the first weight W1 moves down relatively, and a lower fishing net ND is placed between the waterproof sheet H and the seabed at the bottom of the aquaculture farm A. The lower fishing net ND uses the weight W to cover the space between the underside of the waterproof sheet H and the seabed. This causes seawater inside the aquaculture farm A to flow out of the aquaculture farm A. Because the lower fishing net ND is placed below the aquaculture farm A, the cultured organisms in the aquaculture farm A do not flow out of the aquaculture farm A.

[0045] Here, by adjusting the length of the rope L between the connection part with the anchor K and the connection part with the first float F1, the distance between the first float F1 and the second float F2 at high tide can be adjusted. This allows the aquaculture system 1a to control the amount of seawater flowing into the aquaculture site A.

[0046] A design example of the aquaculture system 1a according to the modified example is shown in formula (2). The length L of the upper fishing net between the first float F1 and the second float F2 Ｎｓ and the vertical length L of the waterproof sheet H Ｆ is as shown in FIG.

[0047]

[0048] As shown in formula (2), the amount of seawater flowing into the aquaculture farm A per unit time at high tide is determined by the depth of the first float F1 from the sea surface. According to formula (2), the length L of the rope L between the connection part with the anchor K and the connection part with the first float F1 is determined by taking into account the water level at high tide and the amount of seawater flowing in at high tide specified by the user, etc. Ａ is calculated.

[0049] The formula (2) is merely an example and is not limiting. It may be modified as appropriate depending on the shape of the farm A.

[0050] (Control Device) The control device 10 will be described with reference to FIG.

[0051] The control device 10 is connected by wire or wirelessly to a mechanism (not shown) that changes the length of the rope L. The control device 10 may control one mechanism provided for one rope L, or may collectively control multiple mechanisms provided for multiple ropes L. The mechanism may change the connection position between the rope L and the anchor K, or may change the connection position between the rope L and the first float F1. The mechanism may also change the distance of the rope L by winding or unwinding the rope L between the anchor K and the first float F1.

[0052] The control device 10 calculates the length of the rope L from the amount of seawater that will flow in at the next high tide and the water level at high tide, and controls the mechanism that changes the length of the rope so that the first float F1 and the anchor K are connected at the calculated length.

[0053] 7, the control device 10 includes data on the replacement amount 101, the high tide water level 102, the next rope length 103, and the current rope length 104, and functions of an acquisition unit 121, a calculation unit 122, and a change unit 123. Each piece of data is stored in a storage device such as a memory 902 or a storage 903. Each function is implemented in a CPU 901.

[0054] The exchange amount 101 is the amount of seawater that will flow into the farm A at the next high tide. The exchange amount 101 may be the amount of inflow per unit time, or may be the total amount of seawater that will flow into the farm A from the previous low tide to the next low tide.

[0055] The high tide water level 102 is the water level at the next high tide.

[0056] The next rope length 103 is the next rope length calculated from the replacement amount 101 and the high tide water level 102. The current rope length 104 is the rope length calculated from the amount of seawater flowing in and the water level at the previous high tide, and is the current rope length. The next rope length 103 and the current rope length 104 are each the lengths between the connection part of the rope L with the anchor K and the connection part with the first float F1.

[0057] The acquisition unit 121 acquires the exchange amount 101 of seawater flowing into the aquaculture farm A and the next high tide water level 102. The exchange amount 101 may be acquired from the user terminal 20 or from predetermined exchange amount schedule data, etc. The next high tide water level 102 is acquired, for example, from a tidal estimation API (Application Programming Interface) 30.

[0058] The calculation unit 122 calculates the depth from the sea surface of the first float F1 into which the exchange amount 101 flows, and calculates the length of the rope L at which the first float F1 is located at the calculated depth. More specifically, the calculation unit 122 further obtains the next high tide water level, and calculates the length of the rope L at which the first float F1 is located at the calculated depth at the next high tide water level. The calculation unit 122 outputs the calculated length of the rope L as the next rope length 103.

[0059] The change unit 123 changes the length of the rope L between the connection part with the anchor K and the connection part with the first float F1 to the calculated length. The change unit 123 inputs an instruction to change the length of the rope L to the calculated length to a mechanism that changes the length of the rope L.

[0060] The change unit 123 may compare the next rope length 103 with the current rope length 104 and input an instruction to change the current rope length to the mechanism. If the current rope length 104 is longer, the change unit 123 inputs an instruction to the mechanism to shorten the difference between the next rope length 103 and the current rope length 104. If the current rope length 104 is shorter, the change unit 123 inputs an instruction to the mechanism to lengthen the difference between the next rope length 103 and the current rope length 104.

[0061] 8, an example will be described in which the water levels at the previous and next high tides are different and the rope length is changed depending on the water level at the next high tide. If the water level at the next high tide is higher than the water level at the previous high tide and the amount of seawater exchanged is the same, adjusting the length of the rope L so that the second float F2 is positioned at the sea surface will result in the length of the rope L at the next high tide being longer than the length of the rope L at the previous high tide. The position of the first float F1 to achieve a predetermined exchange amount is defined by the depth from the sea surface, so the higher the water level at high tide, the higher the position of the aquaculture facility A relative to the seabed.

[0062] Therefore, the control device 10 controls the length of the rope L taking into consideration not only the seawater exchange rate 101 but also the water level at high tide.

[0063] The aquaculture method used in the aquaculture system 1 according to the present disclosure will be described with reference to Fig. 9. In the aquaculture method shown in Fig. 9, the control device 10 controls the length of the rope L at the next high tide during aquaculture in the aquaculture farm A. The aquaculture method shown in Fig. 9 is carried out, for example, at low tide.

[0064] In step S1, the control device 10 waits for low tide to arrive. When low tide arrives, the process proceeds to step S2. For example, during the previous process, the control device 10 obtains and stores the time of the next low tide from the tidal estimation API 30. When the time of the next low tide arrives, the control device 10 starts the process from step S2 onwards in Figure 9, or starts a program that performs the process from step S2 onwards.

[0065] In step S2, the control device 10 acquires the amount of seawater to be exchanged at the next high tide. In step S3, the control device 10 acquires the next full water level.

[0066] In step S4, the control device 10 calculates the depth of the first float F1 from the sea surface so that the exchange amount of seawater acquired in step S2 can flow in. In step S5, the control device 10 calculates the rope length so that the first float F1 will be located at the depth calculated in step S4 at the next high tide water level acquired in step S3.

[0067] In step S6, the control device 10 changes the connection position of the rope L to the anchor K or the connection position of the rope L to the first float F1 so that the rope length becomes the length calculated in step S5.

[0068] A case where the same amount of seawater is exchanged at each high tide will be described with reference to Figure 10. The control device 10 adjusts the length of the rope L based on the difference between the water level at the previous high tide and the water level at the next high tide.

[0069] In step S101, the control device 10 acquires the water level of the next high tide and the time of the next low tide.

[0070] In step S102, the control device 10 calculates the difference between the water level at the previous high tide and the water level at the next high tide. In step S103, the control device 10 calculates the difference in anchor rope length using the difference calculated in step S102.

[0071] In step S104, the control device 10 uses the difference calculated in step S103 to control the length of the rope L. If the anchor rope length calculated in step S103 is a positive number, the control device 10 extends the anchor rope, and if it is a negative number, the control device 10 shortens the anchor rope.

[0072] In step S105, the control device 10 records the water level of the next high tide obtained in step S101 in order to calculate the rope length at the next high tide. In step S106, the control device 10 sets the start of the process in Figure 10 to the time of the next low tide obtained in step S101 as the timing for calculating the rope length at the next high tide.

[0073] The aquaculture system 1 according to the present disclosure can control the amount of seawater exchanged into the marine aquaculture farm by utilizing the difference in water level due to the tides. A modified aquaculture system 1a is also similar to the aquaculture system 1.

[0074] The timing of discharging aquaculture wastewater, such as excrement or leftover feed from cultured organisms such as fish or crustaceans, can be controlled. The aquaculture system 1 can discharge aquaculture wastewater at a timing when it can be absorbed as nutrients by the seaweeds used in integrated aquaculture, thereby reducing the impact of marine pollution compared to when aquaculture wastewater is constantly discharged into the sea.

[0075] In the case of integrated aquaculture on the sea surface, seawater with a high dissolved oxygen concentration can be circulated from the seaweed farm to farm A for the target organisms to be cultured. This reduces the risk of the target organisms dying. In conventional integrated aquaculture, the target organisms have died or their growth has been inhibited due to lack of oxygen, but the aquaculture system 1 according to the present disclosure is expected to increase the number of target organisms to be shipped and improve yields.

[0076] Like conventional integrated aquaculture, the aquaculture system 1 is effective in producing seaweed and reducing environmental pollution by recycling nutrients, and is also expected to improve the yield of the aquaculture target organisms. Because the profit margin for seaweed is low, even when an integrated aquaculture system is introduced, aquaculture operators often find it unprofitable. In contrast, the aquaculture system 1 disclosed herein is expected to improve the yield of highly profitable aquaculture target organisms, thereby expanding the benefits for aquaculture operators and leading to the widespread adoption of integrated aquaculture systems. Furthermore, the widespread adoption of integrated aquaculture systems can reduce pollution caused by aquaculture wastewater and promote measures to address the decline in marine resources caused by the disruption of ecosystem balance.

[0077] The control device 10 according to the present disclosure described above uses, for example, a general-purpose computer system including a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device 906. In this computer system, the CPU 901 executes a program loaded on the memory 902, thereby realizing each function of the control device 10.

[0078] The control device 10 may be implemented by one computer or by multiple computers, and may also be a virtual machine implemented on a computer.

[0079] The program of the control device 10 can be stored in a computer-readable recording medium such as a HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), DVD (Digital Versatile Disc), or can be distributed via a network. The computer-readable recording medium is, for example, a non-transitory recording medium.

[0080] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure.

[0081] 1 Aquaculture system 10 Control device 20 User terminal 30 Tidal estimation API 101 Exchange amount 102 High tide water level 103 Next rope length 104 Current rope length 121 Acquisition unit 122 Calculation unit 123 Change unit A Aquaculture site F1, F2 Float H Waterproof sheet K Anchor L Rope NU Upper fishing net ND Lower fishing net W Weight 901 CPU 902 Memory 903 Storage 904 Communication device 905 Input device 906 Output device

Claims

1. An aquaculture system comprising: a waterproof sheet that forms an aquaculture area; an upper fishing net that is attached to the upper side of the waterproof sheet; a first float that is attached to the upper end of the waterproof sheet and is located above the sea surface at low tide; a second float that is attached to the upper fishing net and is located above the sea surface at high tide; a rope that connects the first float to an anchor that is attached to the seabed; and a control device that controls the length of the rope between the connection part with the anchor and the connection part with the first float so that seawater flows into the aquaculture area from between the first float and the second float at high tide.

2. The aquaculture system described in claim 1, wherein the aquaculture site is formed by enclosing a portion of the sea with the waterproof sheet, and the waterproof sheet covers the bottom of the aquaculture site at low tide and opens the bottom at high tide.

3. The aquaculture system described in claim 1, wherein the aquaculture area is formed by separating the edge of the sea with the waterproof sheet, the vertical length of the waterproof sheet is longer than the length from the sea surface to the seabed at low tide and shorter than the length from the sea surface to the seabed at high tide, and the aquaculture area forms an opening on the underside of the waterproof sheet at high tide.

4. An aquaculture system comprising: a waterproof sheet forming a fish farm; an upper fishing net attached to the upper side of the waterproof sheet; a first float attached to the upper end of the waterproof sheet and positioned above the sea surface at low tide; a second float attached to the upper fishing net and positioned above the sea surface at high tide; a rope connecting the first float to an anchor attached to the seabed; and a control device that controls the length of the rope between the connection part with the anchor and the connection part with the first float so that seawater flows into the fish farm from between the first float and the second float at high tide, wherein the control device obtains the exchange amount of seawater flowing into the fish farm; calculates the length of the rope between the connection part with the anchor and the connection part with the first float so that the amount of seawater obtained from between the first float and the second float will flow into the fish farm at high tide; and changes the length of the rope between the connection part with the anchor and the connection part with the first float to the calculated length.

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