Land-based aquaculture system for marine invertebrates

Abstract

To provide a low-cost land-based aquaculture system for marine invertebrates that does not depend on natural seaweeds.SOLUTION: This land-based aquaculture system comprises: a feed tank for culturing seaweeds serving as feed for marine invertebrates by using seawater; a rearing tank for rearing the marine invertebrates by using seawater; and a gas supply device for supplying a gas containing carbon dioxide at a higher concentration than that in the atmosphere to the seawater in the feed tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a land-based marine invertebrate farming system. [Background technology]

[0002] Marine invertebrates such as abalone are farmed using natural seaweed and compound feed. Marine invertebrate farming can be done in two ways: marine farming, where rearing cages are suspended in a bay, and land-based farming, where seawater is drawn into inland concrete tanks. In land-based abalone farming, baby abalone are placed in tanks and fed food until they reach shipping size. The feed used in abalone farming includes natural seaweed and commercially available compound feed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-145984 Summary of the Invention [Problem to be solved by the invention]

[0004] Natural seaweed is widely used as feed because it is inexpensive. However, natural seaweed resources are declining due to coastal denudation caused by feeding damage by sea urchins and diademed seaweed, raising concerns about stable supplies. On the other hand, compound feed is easy to obtain, but is expensive. Furthermore, residues can deteriorate water quality, and the increased frequency of water changes contributes to the high costs of land-based aquaculture.

[0005] The present invention has been made to solve this problem, and aims to provide a low-cost land-based aquaculture system for marine invertebrates that does not depend on natural seaweed. [Means for solving the problem]

[0006] A first aspect for achieving this objective comprises a feeding tank in which seawater is used to cultivate seaweed as food for marine invertebrates, a rearing tank in which seawater is used to rear marine invertebrates, and a gas supply device that supplies gas containing carbon dioxide at a higher concentration than the carbon dioxide concentration in the atmosphere to the seawater in the feeding tank.

[0007] In the second embodiment, in the first embodiment, the gas is a gas obtained by separating and purifying exhaust gas emitted from an exhaust gas source or carbon dioxide in the atmosphere.

[0008] In a third aspect, in the first or second aspect, the pH of the seawater in the rearing tank is made higher than the pH of the seawater in the feeding tank.

[0009] In a fourth aspect, in any one of the first to third aspects, the fish aquarium further comprises a wastewater supply device that supplies a portion of the wastewater from the cultivation tank to the feeding tank.

[0010] In a fifth aspect, in any one of the first to fourth aspects, the marine invertebrate is a shellfish. [Effects of the Invention]

[0011] According to the present invention, seaweed is cultivated by supplying gas containing carbon dioxide at a concentration higher than that of atmospheric carbon dioxide to seawater in a feed tank using a gas supply device, thereby increasing the photosynthetic rate and thereby increasing the yield of seaweed in the feed tank. This allows for the use of small, inexpensive feed tanks. Furthermore, by feeding cultivated seaweed to marine invertebrates in a rearing tank, a low-cost land-based marine invertebrate farming system that does not rely on natural seaweed can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a piping diagram of a land-based aquaculture system according to a first embodiment. [Figure 2] FIG. 10 is a piping diagram of a land-based aquaculture system according to a second embodiment. [Figure 3]FIG. 10 is a piping diagram of a land-based aquaculture system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Figure 1 is a piping diagram of a land-based aquaculture system 10 according to a first embodiment. The land-based aquaculture system 10 is a semi-closed circulation system, and a feed tank 11 and a culture tank 12 are located near a boundary 52 between the sea 50 and the land 51. The culture tank 12 is a tank for cultivating mainly edible marine invertebrates. The feed tank 11 is a tank for cultivating seaweed, which serves as food for the marine invertebrates.

[0014] Examples of marine invertebrates cultivated in the cultivation tank 12 include shellfish such as abalones, turban shells, barnacles, oysters, and scallops, crustaceans such as shrimp and crabs, and sea urchins, all of which belong to the phylum Mollusca, Echinodermata, Arthropoda, Cnidaria, and Annelida. Abalone is a general term for gastropods belonging to the class Gastropoda in the phylum Mollusca, and examples include species of the genus Abalone such as the black abalone, mega-abalone, madaka abalone, and Siberian abalone, and species of the genus Abalone such as the Japanese abalone, mega-abalone, madaka abalone, and Siberian abalone. Sea urchins are a general term for echinoderms belonging to the class Urchins in the phylum Echinodermata, and examples include the purple sea urchin, northern purple sea urchin, sea urchin, Siberian sea urchin, and red sea urchin.

[0015] Examples of seaweed cultivated in the feed tank 11 include green algae, brown algae, red algae, and seagrass. Examples of green algae include the Hibiscales, Ulvales, Cladophorales, Mentholales, Greengrocery, Cauldronales, Myrales, Sclerotiales, Myrales, and Porphyrales. Examples of brown algae include the Dictyotales, Dictyotales, and Chordata such as Myrtles, Scyllales, Sclerotiales, Sclerotiales, Sclerotiales, Sclerotiales, Porphyrales, Laminariales such as Undaria pinnatifida and Laminaria japonica, and Fucales such as Fucidales. Examples of red algae include the Bangiales, Alcalales, Corallineales, Gelidiales, Sclerotiales, Sclerotiales, Gracilariales, Sclerotiales, and Ceratoales. The seaweed to be cultivated is selected appropriately depending on the type of marine invertebrate to be cultivated.

[0016] The water supply pipe 13 is connected to the feed tank 11. The land-based aquaculture system 10 operates a pump 14 connected to the water supply pipe 13 to pump seawater from the ocean 50 and supply the seawater to the feed tank 11. A gas supply device 15 connected to the water supply pipe 13 supplies gas containing carbon dioxide at a higher concentration than the carbon dioxide concentration in the atmosphere to the seawater. A drain pipe 16 connected to the feed tank 11 discharges wastewater from the feed tank 11 into the ocean 50.

[0017] Examples of the gas supply device 15 include a device that supplies exhaust gas emitted from exhaust gas sources (combustion devices such as boilers and incinerators) in factories, power plants, etc. to seawater, and a device that supplies gas obtained by separating and purifying carbon dioxide from exhaust gas or the atmosphere to seawater. An example of a technology for separating and purifying carbon dioxide from exhaust gas or the atmosphere is direct air capture (DAC). Examples of DAC include a technology that captures carbon dioxide by adsorbing or absorbing it into a solid or liquid, and a technology that captures carbon dioxide by membrane separation.

[0018] If there is an exhaust gas source near the land-based aquaculture system 10, the gas obtained by separating and purifying carbon dioxide in the exhaust gas or the exhaust gas may be supplied directly to the seawater. If the exhaust gas source is far from the land-based aquaculture system 10, liquefied carbon dioxide gas obtained by separating and purifying carbon dioxide in the exhaust gas or the atmosphere may be transported to the vicinity of the land-based aquaculture system 10, and the gas obtained by vaporizing the liquefied carbon dioxide gas near the land-based aquaculture system 10 may be supplied to the seawater.

[0019] Gas containing carbon dioxide at a higher concentration than that in the atmosphere is supplied to the seawater in the feed tank 11 by the gas supply device 15, which promotes photosynthesis of seaweed, which requires carbon dioxide and sunlight. This promotes the growth of seaweed in the feed tank 11, thereby increasing the seaweed yield. Furthermore, compared to when carbon dioxide is not supplied to the seawater, this allows a larger amount of seaweed to be cultivated per unit volume of the feed tank 11, allowing the feed tank 11 to be smaller. This therefore reduces the cost (equipment cost) required for the feed tank 11.

[0020] The water supply pipe 17 is connected to the cultivation tank 12. The land-based aquaculture system 10 operates a pump 18 connected to the water supply pipe 17 to pump seawater from the ocean 50 and supply the seawater to the cultivation tank 12. The seawater in the feed tank 11 is neutral to acidic due to the large amount of dissolved carbon dioxide, but because seawater is supplied from the ocean 50 to the cultivation tank 12 through the water supply pipe 17, the hydrogen ion concentration (pH) of the seawater in the cultivation tank 12 can be made higher than the pH of the seawater in the feed tank 11. Because the seawater in the feed tank 11 can be made alkaline, which is suitable for marine invertebrates, it is possible to avoid inhibiting the growth of the marine invertebrates in the cultivation tank 12.

[0021] Since seaweed harvested from the feeding tank 11 is fed to the marine invertebrates in the cultivation tank 12, the marine invertebrates do not have to rely on natural seaweed for food. Furthermore, the cost of feed can be reduced compared to when all feed is compound feed. Since the amount of compound feed used can be reduced, the deterioration of water quality in the cultivation tank 12 due to compound feed residue can be reduced.

[0022] A circulating water pipe 19 connects the rearing tank 12 and the feeding tank 11. A pump 20 arranged in the circulating water pipe 19 supplies seawater from the rearing tank 12 to the feeding tank 11 through the circulating water pipe 19. A filtration device 21 is arranged in the circulating water pipe 19 between the rearing tank 12 and the pump 20. The filtration device 21 filters and purifies the seawater in the rearing tank 12. Examples of the filtration device 21 include a filter, strainer, or sand filter.

[0023] A sterilizer 22 is disposed in the circulating water pipe 19 between the pump 20 and the feed tank 11. The sterilizer 22 uses electrolysis, ultraviolet light, ozone, etc. to kill or reduce bacteria, mold, algae, germs, viruses, etc. in the seawater. This reduces the deterioration of the water quality of the seawater supplied from the circulating water pipe 19 to the feed tank 11, thereby protecting the seaweed from diseases, etc.

[0024] The water supply pipe 23 connects the part of the circulating water pipe 19 downstream of the sterilizer 22 to the cultivation tank 12. Seawater that has passed through the sterilizer 22 is supplied to the cultivation tank 12 through the water supply pipe 23. This reduces the deterioration in the water quality of the seawater supplied from the circulating water pipe 19 to the cultivation tank 12, thereby protecting marine invertebrates from diseases and the like.

[0025] The drain pipe 24 connects the downstream portion of the circulating water pipe 19 connected to the water supply pipe 23 to the cultivation tank 12. The drain supply device 26 includes the drain pipe 24, the pump 20, and the circulating water pipe 19. The drain supply device 26 allows a portion of the wastewater from the cultivation tank 12 to flow from the drain pipe 24 into the circulating water pipe 19, which then supplies it to the feeding tank 11. Generally, seaweed growth requires 11 essential elements (C, H, O, N, P, K, Ca, Mg, S, Na, Cl) and 13 trace elements (Fe, Mn, Cu, Zn, Mo, B, I, Br, Sr, Co, V, Li, Ru). Because a portion of the excrement of marine invertebrates in the cultivation tank 12 is supplied to the feeding tank 11, the components (essential and trace elements) contained in the excrement can reduce the cost of adding essential and trace elements to the circulating seawater.

[0026] A drain pipe 25 connected to the filtration device 21 discharges the wastewater from the cultivation tank 12 filtered by the filtration device 21 into the sea 50. After passing through the filtration device 21 and the sterilization device 22, part of the wastewater from the cultivation tank 12 is supplied to the feed tank 11 via the circulating water pipe 19, part is supplied to the cultivation tank 12 via the water supply pipe 23, and the remainder passes through the drain pipe 25, thereby reducing the amount of wastewater discharged into the sea 50. Since pollution of the sea 50 by wastewater from the cultivation tank 12 can be reduced, the environmental impact of the land-based aquaculture system 10 can be reduced.

[0027] A second embodiment will be described with reference to Figure 2. In the first embodiment, a semi-closed circulation type land-based aquaculture system 10 was described. In contrast, in the second embodiment, a free-flowing type land-based aquaculture system 30 will be described. In the second embodiment, the same parts as those described in the first embodiment are designated by the same reference numerals, and the following description will be omitted.

[0028] 2 is a piping diagram of a land-based aquaculture system 30 according to a second embodiment. The land-based aquaculture system 30 operates a pump 14 connected to a water supply pipe 13 to pump seawater from the ocean 50 and supply it to the feed tank 11, and operates a pump 18 connected to a water supply pipe 17 to pump seawater from the ocean 50 and supply it to the growth tank 12. A gas supply device 15 supplies gas containing carbon dioxide at a higher concentration than that in the atmosphere to the seawater in the feed tank 11.

[0029] A drain pipe 31 connected to the cultivation tank 12 discharges wastewater from the cultivation tank 12 into the sea 50. A supply pipe 32 connects the drain pipe 31 to the feeding tank 11. A portion of the wastewater from the cultivation tank 12 is supplied to the feeding tank 11 through the supply pipe 32 (drainage supply device). Because a portion of the excrement of marine invertebrates in the cultivation tank 12 is supplied to the feeding tank 11, it is expected that the components contained in the excrement will promote the growth of seaweed in the feeding tank 11. The land-based aquaculture system 30 can be configured more simply than the land-based aquaculture system 10.

[0030] A third embodiment will be described with reference to Figure 3. In the first embodiment, a semi-closed circulation land-based aquaculture system 10 was described. In contrast, in the third embodiment, a completely closed circulation land-based aquaculture system 40 will be described. In the third embodiment, the same parts as those described in the first embodiment are designated by the same reference numerals, and the following description will be omitted.

[0031] 3 is a piping diagram of a land-based aquaculture system 40 according to a third embodiment. In the land-based aquaculture system 40, a seawater circulation path is formed by a connecting pipe 41 that connects the feed tank 11 and the cultivation tank 12, and a circulating water pipe 19 that connects the cultivation tank 12 and the feed tank 11. A gas supply device 15 is connected to the circulating water pipe 19 between the sterilizer 22 and the feed tank 11. Artificial seawater or natural seawater is used as the seawater. A pump 20 disposed in the circulating water pipe 19 circulates seawater through the circulating water pipe 19, the feed tank 11, the connecting pipe 41, and the cultivation tank 12.

[0032] A calcium supplying device 42 and a pH adjusting device 43 are disposed in the connecting pipe 41. The calcium supplying device 42 is a device that supplies calcium to the seawater flowing through the connecting pipe 41. An example of the calcium supplying device 42 is one that brings the seawater flowing through the connecting pipe 41 into contact with a calcium source such as limestone. Since the seawater in the feeding tank 11 to which carbon dioxide has been supplied by the gas supplying device 15 is mainly acidic, calcium from the calcium supplying device 42 dissolves into the seawater. Since the calcium concentration of the seawater in the growing tank 12 increases, the growth of the shells of the marine invertebrates is promoted when the marine invertebrates are shellfish.

[0033] The pH adjuster 43 is a device that adjusts the seawater flowing through the connecting pipe 41 to an alkaline state. An example of a pH adjuster 43 is one that adds a water quality adjuster to the seawater. This makes it possible to make the pH of the seawater in the cultivation tank 12 higher than the pH of the seawater in the feeding tank 11. Since the seawater in the feeding tank 11 can be made alkaline, which is suitable for marine invertebrates, it is possible to prevent the growth of the marine invertebrates in the cultivation tank 12 from being inhibited.

[0034] The denitrification device 44 connected to the filtration device 21 is a device that breaks down ammonia nitrogen and nitrite nitrogen contained in seawater. Examples of the denitrification device 44 include fixed-bed, upflow sludge bed, and coral sand types that use microorganisms (denitrifying bacteria). The denitrification device 44 can reduce deterioration in the water quality of the seawater supplied to the feed tank 11 and the cultivation tank 12. The land-based aquaculture system 40 is less susceptible to the external environment, and can control the growth environment for seaweed and marine invertebrates while preventing water pollution due to wastewater.

[0035] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention.

[0036] Although not explained in the embodiment, it is of course possible to supply oxygen to the seawater in the cultivation tank 12 or perform aeration. This is to improve the growth environment for the marine invertebrates in the cultivation tank 12. It is also of course possible to feed compound feed to the marine invertebrates in the cultivation tank 12. This is because if there are nutrients that are lacking in seaweed alone, the compound feed can supplement those nutrients. In this case, since seaweed is also fed to the marine invertebrates, the amount of compound feed used to supplement the seaweed can be reduced. Since the amount of compound feed residue can be reduced, the deterioration of water quality due to residue can be reduced.

[0037] Although not described in the embodiment, it is of course possible to adjust the temperature of the seawater in the feeding tank 11 and the cultivation tank 12, and to adjust the light intensity in the feeding tank 11 and the cultivation tank 12. This is to create a good environment for the growth of seaweed and marine invertebrates. [Explanation of symbols]

[0038] 10,30,40 Land-based aquaculture systems 11 Feeding tank 12 Breeding tank 15 Gas supply equipment 26 Drainage supply equipment

Claims

1. 1. A land-based marine invertebrate farming system comprising: a feeding tank in which seaweed is cultivated using seawater as food for the marine invertebrates; a cultivation tank for cultivating the marine invertebrates using seawater; a gas supply device that supplies gas containing carbon dioxide at a concentration higher than the carbon dioxide concentration in the atmosphere to the seawater in the feed tank.

2. 2. The land-based aquaculture system according to claim 1, wherein the gas is an exhaust gas emitted from an exhaust gas source or a gas obtained by separating and purifying carbon dioxide in the atmosphere.

3. 3. The land-based aquaculture system according to claim 1, wherein the pH of the seawater in the rearing tank is set higher than the pH of the seawater in the feeding tank.

4. The land-based aquaculture system according to claim 1 or 2, further comprising a wastewater supply device that supplies a portion of the wastewater from the culture tank to the feeding tank.

5. 3. The land-based aquaculture system according to claim 1 or 2, wherein the marine invertebrates are shellfish.

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