Artificial fishing bank and method for producing artificial fishing bank

Abstract

This artificial fishing bank includes at least one reinforced concrete pole member 11 obtained by cutting a reinforced concrete pole that has a cavity therein. The cavity of the reinforced concrete pole member 11 is filled with a filler. The filler includes at least one of the following: a crushed material obtained by crushing or cutting at least one of cement, mortar, concrete, and reinforced concrete; suspension wire; metal attached to the reinforced concrete pole; and shells of fish and shellfish.

Description

Artificial reefs and methods for manufacturing them

[0001] TECHNICAL FIELD The present disclosure relates to artificial reefs and methods for manufacturing artificial reefs.

[0002] Due to the recent decline in fish catches, artificial reefs have been installed in the sea to serve as breeding grounds for fish and shellfish. Artificial reefs are mainly submerged structures made of concrete or steel.

[0003] Research into rocky shore denudation has suggested that a lack of iron ions supplied from rivers is the main cause of rocky shore denudation, and artificial steel reefs made of steel have been considered as a possible solution to this problem (Patent Document 1).

[0004] Japanese Patent Publication No. 4-108327

[0005] Masafumi Kitatsuji, "Prototype of an Artificial Reef that Can Sustainably Supply Iron and Nutrients," Abstracts of the 2021 (70th) Annual Meeting of the Japanese Society of Irrigation, Drainage and Forestry Engineering, Vol. 490. Yoshiharu Morimoto, Tetsuo Toyama, "Research on the Effective Use of Old Concrete Utility Poles as Artificial Reefs," Chubu Electric Power Co., Inc., Research Material No. 77, September 1986.

[0006] Patent Document 1 describes technology related to the structure of frames for artificial fish reefs, and claims that as steel structures corrode in seawater, they supply iron to the seawater, which causes a large amount of phytoplankton to grow, which in turn increases zooplankton and provides an abundant source of food.However, over the long term, corrosion of iron (steel) structures causes the components to thin out, making it impossible to maintain their structure.

[0007] Therefore, Non-Patent Document 1 considers an artificial reef in which steel slag is placed inside a concrete reef and iron ions are supplied from the steel slag. However, although the artificial reef in Non-Patent Document 1 has high performance as an artificial reef, it has the problem of high manufacturing costs because it is manufactured as an artificial reef from the beginning. Furthermore, in recent years, global warming due to an increase in atmospheric CO2 has become a global problem.

[0008] Non-Patent Document 2 considers using old electric poles as artificial reefs. In the artificial reefs described in Non-Patent Document 2, the electric poles used are hollow inside, so the propagation of relatively small organisms is not taken into consideration.

[0009] The present disclosure has been made in consideration of the above circumstances, and aims to provide an inexpensive artificial fishing reef that can maintain a relatively long lifespan, supply iron ions to seawater, and absorb CO2.

[0010] An artificial fishing reef according to one embodiment of the present disclosure comprises at least one reinforced concrete pole member cut from a reinforced concrete pole having a cavity therein, the cavity of the reinforced concrete pole member being filled with a filler, the filler including at least one of crushed or cut pieces of at least one of cement, mortar, concrete, and reinforced concrete, a suspension wire, metal attached to the reinforced concrete pole, and seafood shells.

[0011] A method for manufacturing an artificial reef according to one embodiment of the present disclosure includes the steps of cutting a reinforced concrete pole having an internal cavity to produce a plurality of reinforced concrete pole members, filling the plurality of reinforced concrete pole members with a filler, and connecting the plurality of reinforced concrete pole members after filling, wherein the filler includes at least one of crushed or cut pieces of at least one of cement, mortar, concrete, and reinforced concrete, suspension wire, metal attached to the reinforced concrete pole, and seafood shells.

[0012] According to the present disclosure, it is possible to provide an inexpensive artificial fishing reef that can maintain a relatively long lifespan, supply iron ions to seawater, and absorb CO2.

[0013] FIG. 1 is an example of an artificial reef assembled in a square shape. FIG. 2 is an example of an artificial reef assembled in a cross shape. FIG. 3 is an example of an artificial reef assembled in a triangular shape. FIG. 4 is an example of an artificial reef in which the artificial reefs of FIG. 1 are stacked in multiple layers. FIG. 5 is an example of an artificial reef in which multiple reinforcing bar CP members are bundled and connected in three dimensions. FIG. 6A is a diagram illustrating the connection of two mounting pole bands. FIG. 6B is a schematic diagram showing reinforcing bar CP members connected using attachment bands. FIG. 7 is a diagram illustrating the connection of reinforcing bar CP members using bands. FIG. 8 is a diagram illustrating an example of a layered artificial reef. FIG. 9 is a diagram illustrating a method of installing an artificial reef.

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0015] In this embodiment, waste reinforced concrete poles with internal cavities (hereinafter referred to as "rebar CP") are reused as artificial fishing reefs. This makes it possible to provide artificial fishing reefs that can be manufactured inexpensively, supply iron ions to seawater, and absorb CO2. Rebar CP is used, for example, in electric poles and telephone poles.

[0016] As the rebar inside the rebar CP corrodes, iron ions are supplied to the sea. Also, when CaO, the main component of cement in the concrete of the rebar CP, neutralizes, it absorbs CO2 from the seawater, reducing the amount of CO2 in the seawater. As the CO2 in the seawater decreases, atmospheric CO2 dissolves into the seawater to maintain equilibrium. This also has the effect of absorbing atmospheric CO2.

[0017] Furthermore, in the case of typical concrete artificial reefs, heating (calcination) is required to produce clinker from limestone, a raw material for cement, and limestone, the main raw material, emits CO2 when heated. Furthermore, the calcination of limestone also uses fuel such as coal, which also emits CO2. In contrast, the artificial reef of this embodiment uses waste rebar CP, which has the advantage of emitting almost no CO2 when manufacturing the materials for the artificial reef.

[0018] In this embodiment, based on the above findings, an artificial reef was created using existing hollow, columnar reinforcing bars (CP). It is preferable to use reinforcing bars (CP) manufactured by centrifugal compaction. Examples of reinforcing bars (CP) manufactured by centrifugal compaction include utility poles and telegraph poles. Therefore, it is preferable to use discarded utility poles or telegraph poles for the artificial reef of this embodiment.

[0019] Regular reinforced concrete carbonates in a relatively short time, causing the internal rebars to corrode and expand, resulting in internal cracks and making it unable to maintain its shape as a structure over the long term. On the other hand, the reinforced concrete (CP) used in utility poles and telephone poles is manufactured using centrifugal compaction and has a higher density than regular reinforced concrete, making it less susceptible to carbonation and giving it a longer lifespan. Furthermore, the reinforced concrete (CP) used in utility poles and telephone poles can maintain its shape as a structure for a longer period of time underwater than cylinders made with regular reinforced concrete, even with the same thickness of concrete cover. Concrete cover thickness refers to the thickness of the concrete from the concrete surface to the rebar.

[0020] If you want to supply iron ions or absorb CO2 in a short period of time, you can also use regular reinforced concrete that has not been centrifugally compacted, although it will have a shorter lifespan. In other words, centrifugally compacted reinforced concrete (CP) has a longer structural lifespan, but non-centrifugally compacted reinforced concrete (CP) will neutralize more quickly and the corrosion of the internal rebar will also progress more quickly, allowing it to absorb more CO2 in a short period of time and supply more iron ions to the surrounding seawater. Therefore, you can simply select the appropriate reinforced concrete (CP) depending on the required lifespan.

[0021] (Fabrication of Reinforced Concrete Pole) The artificial reef of this embodiment includes at least one reinforced concrete pole member (reinforced concrete pole member) cut from a hollow reinforced concrete pole (reinforced concrete pole). That is, the artificial reef may include one reinforced concrete pole member or multiple reinforced concrete pole members.

[0022] Reinforced concrete CP members are cylindrical members with internal cavities that allow small organisms (zooplankton, shrimp, crabs, small fish, etc.) to enter inside, making them effective as artificial reefs simply by placing them on the seabed.

[0023] Typically, rebar CP for utility poles, telegraph poles, etc. is 6 to 10 meters or longer. If the rebar CP is too long, the utilization efficiency of living organisms in the central part (longitudinal direction) of the cavity of the rebar CP member decreases. In addition, taking into consideration ease of transportation and installation, in this embodiment, rebar CP members cut to an appropriate length are used for artificial fishing reefs.

[0024] When using reinforcing bar CP for utility poles or telegraph poles, the diameter of the reinforcing bar CP member is about 10 to 10 cm. From the viewpoint of the utilization efficiency of the organisms in the central part of the reinforcing bar CP member, the diameter of the reinforcing bar CP member is preferably 1 / 20 or less of the length of the reinforcing bar CP member, and more preferably 1 / 10 or less.

[0025] However, if the length of the reinforced concrete CP members is too short, there is a disadvantage in that the number of artificial reefs made using the reinforced concrete CP members will increase, and more materials will be required to connect the reinforced concrete CP members together. Considering the balance between this disadvantage and ease of handling during transportation, the length of the reinforced concrete CP members should preferably be 1 m or more and less than 2.5 m, and more preferably 1 m or more and less than 2.2 m.

[0026] Reinforced concrete reinforced concrete members less than 2.5m in length can fit within the width of a 2.5m-wide medium- or large-sized truck bed, while reinforced concrete reinforced concrete members less than 2.2m in length can fit within the width of many medium- or large-sized truck beds, improving transportation efficiency. Furthermore, with the exception of reinforced concrete reinforced concrete members with a significantly larger diameter, artificial reefs consisting of three connected reinforced concrete reinforced concrete members filled with filler (described below) or four connected reinforced concrete reinforced concrete members filled with filler can often be constructed within 950kg. 950kg is the weight that can be lifted by a hydraulic crane for small vessels.

[0027] In addition, the ends (terminal portions) of rebar CP are generally filled with mortar or the like and closed. Therefore, rebar CP components may be fabricated by first cutting the ends of the rebar CP and then cutting the cylindrical rebar CP with both ends open to a predetermined length. The cut ends of the rebar CP can be crushed and used as filler.

[0028] In this embodiment, a 7-m-long utility pole with a 140 mm diameter at the end, a 233 mm diameter at the butt, and a length of 7 m was used as the rebar CP. The end of the utility pole was cut off, and the rebar CP member was cut to a length of 2.2 m to create an artificial fishing reef. The end is the end of the utility pole with the smaller diameter, and the butt is the end of the utility pole with the larger diameter.

[0029] (Connection of Reinforced Concrete Members) In this embodiment, an artificial reef is created by connecting multiple reinforced concrete members. The artificial reef may be made up of multiple reinforced concrete members connected in three dimensions, or may be made up of multiple layers of three-dimensionally connected members. Note that if the artificial reef is made up of a single reinforced concrete member, the connection process described below is not necessary.

[0030] 1 shows an example of an artificial fishing reef assembled in a grid pattern (square) of four reinforcing bar CP members 11. While it is possible to simply pile up multiple reinforcing bar CP members 11 randomly in the sea without connecting them, in this embodiment, the four reinforcing bar CP members 11 are connected and assembled in a grid pattern.

[0031] The reinforcing bar CP members 11 may be assembled in a manner other than that shown in Fig. 1. For example, as shown in Fig. 2, two reinforcing bar CP members 11 may be assembled in a cross shape, or as shown in Fig. 3, three reinforcing bar CP members 11 may be assembled in a triangular shape. Furthermore, although not shown, five or more reinforcing bar CP members 11 may be assembled in a polygonal shape.

[0032] Furthermore, an artificial reef may be made by stacking the assembled reinforcing bar CP members 11 in multiple layers. Figure 4 shows an example of an artificial reef made by stacking the reinforcing bar CP members 11 assembled in the grid pattern of Figure 1 in multiple layers. Also, as shown in Figure 5, an artificial reef may be made by simply bundling multiple reinforcing bar CP members 11 and connecting them three-dimensionally.

[0033] Furthermore, it is desirable that the weight of an artificial reef made by connecting multiple rebar CP members and filling each member with a filler be 950 kg or less. This is because the maximum load capacity of cranes for small vessels is often around 950 kg. If the weight of the artificial reef is 950 kg or less, a large crane ship is not required, and the artificial reef can be installed in the sea at low cost using a crane for a small vessel.

[0034] As mentioned above, the weight of each rebar CP member cut to a length of approximately 2.2 m varies between the end and the butt end, but is around 80 kg to 115 kg, averaging just under 100 kg. When four rebar CP members are connected and assembled in a grid pattern, the rebar CP member alone weighs approximately 400 kg, and it is possible to put filler inside as long as the total weight does not exceed 950 kg.

[0035] Depending on the type of rebar CP, there are some that are thicker and heavier. For example, a utility pole (rebar CP) that is 190 mm in diameter at the end, 390 mm at the butt end, and 15 m long weighs approximately 1,300 kg. If this utility pole is cut into lengths of approximately 2.2 m, the rebar CP member at the end weighs 120 kg, and the rebar CP member at the butt end weighs nearly 220 kg. If four rebar CP members near the butt end are connected and assembled in a grid pattern, there is almost no room left to pack the filler material inside.

[0036] It is possible to cut the utility poles to shorter lengths and use shorter rebar CP members, but this would increase the number of connections required and increase costs. In such cases, it is possible to balance the rebar CP members at the ends and adjust them so that the total weight of the connected rebar CP members when filled with filler is less than 950 kg, or to reduce the number of connected rebar CP members (for example, by connecting three rebar CP members in a triangle) so that the total weight of the artificial reef when filled with filler is less than 950 kg.

[0037] In addition, rebars CP with a large diameter or the butt end of rebars CP are cut to a relatively short length, and rebars CP with a small diameter or the butt end of rebars CP are cut to a relatively long length. Multiple rebars CP cut to different lengths can be combined as needed to form an equilateral triangle, a triangle other than a regular square (an isosceles triangle), or a square (a rectangle), and the total weight of the artificial reef when filled with filler can be adjusted to less than 950 kg.

[0038] Some types of rebar CP are even thicker and heavier. For example, a high-strength rebar CP pole with a 400mm diameter end, a 613mm diameter butt, and a length of 16m weighs approximately 4,600kg, with a weight of nearly 350kg per meter at the butt end. Therefore, even if three 1m-long rebar CP pieces were connected in a triangle, the weight would exceed 950kg (in reality, it would be difficult to connect three 600mm-diameter rebar CP pieces cut to 1m lengths). In the case of rebar CP with a particularly high weight per unit length, each piece cut to a specified length can be filled with a filler and dropped into the sea as a single artificial fishing reef without being connected.

[0039] Anything strong enough, such as rope or wire, can be used to connect rebar CP members. For example, multiple rebar CP members can be connected using accessories attached to the rebar CP (electric poles, telegraph poles, etc.) to be discarded. Accessories include pole bands (swivel bands) and suspension wires (steel strands, guy wires). Pole bands are described below. https: / / taiyo-tsushin.com / power-components / ibt-206 / https: / / www.iwabuchi.co.jp / service / pdfjs / web / viewer.html?file=iwabuchi_catalog.pdf#zoom=100

[0040] A pole sling is a metal piece wrapped around a utility pole to secure a suspension wire to the pole. Pole slings are almost always installed on utility poles or telegraph poles. Because of this, they are often discarded along with the utility poles or telegraph poles, and by reusing them, artificial fishing reefs can be created inexpensively. Furthermore, pole slings can supply iron ions into the ocean as they corrode.

[0041] FIG. 6A is a diagram illustrating the connection of two pole bands. The pole bands 60A and 60B shown in the figure each include a band 61 and a hook bolt 62. A connecting member 70, such as a U-bolt, is attached to the hook bolts 62 of the pole bands 60A and 60B to connect the rebar CP member (not shown) to which the pole band 60A is attached and the rebar CP member (not shown) to which the pole band 60B is attached. The connecting member 70 may be, for example, a U-bolt 71 and a plate 72 with two holes corresponding to the U-bolt 71. After the U-bolt 71 is attached to the hook bolts 62 of the pole bands 60A and 60B, the plate 72 is secured to the U-bolt 71 using bolts or the like.

[0042] 6B is a schematic diagram showing reinforcing bar CP members 11 connected using mounting bands 60A, 60B and connecting members 70. Pole mounting bands 60A, 60B are wound around the connecting portions of each reinforcing bar CP member 11, and the pole mounting bands 60A, 60B are connected to each other using connecting members 70. This allows the reinforcing bar CP members 11 wrapped with the pole mounting bands 60A, 60B to be connected.

[0043] Furthermore, as shown in Figure 7, in the case of pole mounting bands 60A, 60B having sufficiently long bands 61, two reinforcing bar CP members 11 may be directly connected using the bands 61. In this case, it is desirable to cross the bands 61. Also, two reinforcing bar CP members 11 may be directly connected using suspension wires. In this case, it is desirable to cross the suspension wires as shown in Figure 7.

[0044] (Filling of Reinforced Concrete Component) The cavity of the reinforced concrete component may be filled with a filling material, which may include at least one of crushed or cut pieces of cement, mortar, concrete, and reinforced concrete, a suspension wire, metal attached to the reinforced concrete pole, and seafood shells.

[0045] The filler was sized to fit into the cavities inside the reinforced concrete CP members. The filler allows many small gaps to be formed inside the reinforced concrete CP members, reducing the size of organisms that can get inside (zooplankton, shrimp, crabs, small fish, etc.), allowing these organisms to reproduce more effectively. For the reproduction of organisms, it is not desirable for the filler to be too small, and it is preferable for it to be crushed so that its length, width, and height are each around a few centimeters to a dozen centimeters.

[0046] It is also preferable to use rebar CP from discarded utility poles, telegraph poles, etc. as the filler. By crushing the rebar CP, the rebar (several meters long) that was inside can be recovered. Therefore, the recovered rebar (or cut pieces of rebar) is first placed into the cavity of the rebar CP member, and the remaining space is filled with crushed concrete. This filling creates many small gaps inside the rebar CP member, reducing the size of organisms that can penetrate inside, allowing these organisms to reproduce more effectively.

[0047] Furthermore, when crushed rebar CP is used as the filler, the rebar is exposed, which has the advantage of quickly corroding the iron, quickly supplying iron ions to the surrounding seawater. Crushing the concrete also increases the concrete's surface area, which increases the total amount of CO2 absorbed and also makes it possible to speed up the CO2 absorption process.

[0048] After filling the inside of the cylindrical reinforced concrete member with this kind of filler, mesh lids (which allow seawater and living organisms to enter and exit) are placed on both ends of the reinforced concrete member to prevent the filler from escaping. The mesh of the lid should be spaced a few centimeters apart so that small living organisms and seawater can move in and out of the reinforced concrete member.

[0049] In this embodiment, crushed rebar CP is used as the filler, but this is not limiting. Reinforced concrete structures, hardened cement, mortar, concrete, etc. may also be crushed (cut) and used as the filler. To supply iron ions, it is desirable to crush reinforced concrete containing rebar and place the rebar in the filler. By filling the interior of the reinforcing bar CP member with crushed cement, mortar, concrete, reinforced concrete, etc., the total amount of CO2 absorbed can be increased. Furthermore, crushing cement, mortar, concrete, reinforced concrete, etc. increases the surface area, which can also increase the CO2 absorption speed.

[0050] Furthermore, when rebar CP (reinforced concrete poles) such as utility poles and telephone graph poles are discarded, the suspension wires (steel strands) used to hang communication or power cables are often discarded at the same time. These suspension wires can be cut to an appropriate length and filled inside the rebar CP member. The suspension wires can also corrode and supply iron ions to the surrounding sea area. When using the suspension wires as filling material, it is desirable to first place the recovered suspension wires together with the rebar inside the rebar CP member, as with the rebar mentioned above, and then fill the remaining space with crushed concrete. This filling creates many small gaps, reducing the size of organisms that can fit inside (zooplankton, shrimp, crabs, small fish, etc.), allowing these organisms to reproduce more effectively.

[0051] In addition, since the various steel hardware (metal) attached to the rebar CP and suspension wires of utility poles and telegraph poles is often discarded at the same time, these hardware can also be used as filler to fill the inside of the rebar CP components. These hardware can also corrode and supply iron ions to the surrounding sea area.

[0052] Furthermore, to allow relatively large organisms to enter the interior of the reinforced concrete CP members, artificial reefs can be constructed by assembling a mixture of reinforced concrete CP members filled with filler and unfilled reinforced concrete CP members (or reinforced concrete CP members with a small amount of filler, leaving a relatively large amount of empty space). This configuration is expected to support the reproduction of organisms of a wide range of sizes.

[0053] The interior of the rebar CP member may be filled with fillers other than those mentioned above. For example, if crushed rebar CP, suspension wire cut to a specified length, and various metal fittings are not enough, the lack of filler can be supplemented by filling with shells of seafood such as oysters and scallops. Using seafood shells as filler creates many small gaps, reducing the size of organisms that can enter the interior. Shells of shellfish such as oysters and scallops are derived from shellfish that originally existed in the sea, so they have a low environmental impact on the ocean. In addition, many food processors are struggling with the disposal of farmed oyster and scallop shells, so filling with these shells can also contribute to solving the waste problem.

[0054] (Installation of artificial reefs) At least one reinforced concrete CP member (artificial reef) filled with a filler material is sunk into the seabed and installed. Considering transportation and installation, it is preferable that the length of each reinforced concrete CP member be between 1 m and 2.5 m, and that in the case of an artificial reef made up of multiple connected reinforced concrete CP members, the weight of the connected artificial reef (including the filler material) be 950 kg or less.

[0055] Furthermore, an artificial reef made of multiple connected rebar CP members may be sunk or installed individually on the seabed. Alternatively, as shown in Figure 8, multiple artificial reefs made of connected rebar CP members may be prepared, dropped onto the seabed, and randomly stacked to form a layered artificial reef. Stacking multiple artificial reefs can achieve greater effectiveness as an artificial reef. Figure 8 shows an example of a layered artificial reef made of multiple artificial reefs (see Figure 1) made of four connected rebar CP members in a square (lattice pattern).

[0056] In addition, an artificial reef made of multiple connected reinforcing bar CP members may be installed as a single artificial reef by using both a single reinforcing bar CP member.

[0057] When multiple artificial reefs are stacked and installed at a specific point (position) underwater (on the seabed), they can be dropped from the sea, aiming at the same specific point on the seabed. However, there are waves and currents on the sea, making it difficult to drop the artificial reefs stably at the same targeted point on the seabed.

[0058] Therefore, in the case of an artificial reef (FIGS. 1 and 3) in which reinforcing bar CP members are connected in a polygonal shape (ring) such as a triangle or a square, as shown in Figure 9, one end of a rope-like member 90 may be tied to the first artificial reef 10A to be dropped, and the next artificial reef 10B to be dropped may be dropped into the sea with the rope-like member 90 threaded through the inner space (ring) of the reef. This allows the artificial reefs 10A and 10B to be dropped stably at the same point in the sea, and the artificial reefs 10A and 10B to be stacked reliably in three dimensions.

[0059] Any material with sufficient strength can be used for this rope-like member 90, but here we used a suspension wire (steel strand) used to run cables between utility poles. Suspension wires are often collected at the same time as discarding rebar CP, and by utilizing them when installing artificial reefs, they corrode and release iron ions into the surrounding sea area, thereby increasing the productivity of the sea area. The suspension wires can be cut and used as filler, but they can also be used as guide ropes when installing artificial reefs on the seabed like this.

[0060] Furthermore, when using a single unconnected rebar CP member as an artificial fishing reef, one end of the rope-like member 90 can be passed through a hole in a scaffolding bolt provided in the rebar CP member, and the artificial fishing reef made of a single rebar CP member can also be dropped at a desired position on the seabed.

[0061] (Method for manufacturing an artificial reef) Next, a method for manufacturing an artificial reef according to this embodiment will be described.

[0062] In this embodiment, a hollow reinforcing bar CP (e.g., utility pole, telegraph pole, etc.) is cut to produce multiple reinforcing bar CPs (Step 1). Then, the multiple reinforcing bar CP components thus produced are filled with a filler (Step 2). As described above, the filler includes at least one of crushed or cut pieces of cement, mortar, concrete, and reinforced concrete, suspension wires, metal attached to the reinforced concrete pole, and seafood shells. Finally, the multiple reinforcing bar CP components are connected together to produce an artificial reef (Step 3). Note that Steps 2 and 3 may be performed in reverse order. Furthermore, Step 3 is unnecessary when using a single reinforcing bar CP component.

[0063] (Effects) The artificial fishing reef of this embodiment described above comprises at least one reinforcing bar CP member formed by cutting reinforcing bar CP with a cavity inside, and the cavity of the reinforcing bar CP member is filled with a filler, which includes at least one of crushed or cut pieces of at least one of cement, mortar, concrete and reinforced concrete, a suspension wire, metal attached to the reinforced concrete pole, and seafood shells.

[0064] In this embodiment, an inexpensive artificial reef can be provided that can maintain a relatively long lifespan, supply iron ions to seawater, and absorb CO. In other words, in this embodiment, an artificial reef that serves as a breeding ground for fish and shellfish mainly in coastal waters can be created extremely cheaply and in a short time.

[0065] Conventional artificial reefs, made of concrete, have a long lifespan but cannot supply iron ions to the surrounding seawater, requiring a separate source of iron ions, while steel reefs can supply iron ions to the surrounding seawater but have the problem of not being able to maintain their structure over the long term due to corrosion. On the other hand, according to this embodiment, an artificial reef that has a long lifespan and combines the advantages of concrete and steel artificial reefs can be produced at a very low cost using waste materials.

[0066] Non-Patent Document 2 reports an artificial reef using utility poles, but this artificial reef does not contain any filler material inside the utility poles. In contrast, the artificial reef of this embodiment uses a filler material, such as crushed CP rebar, inside the rebar. This creates many small gaps, reducing the size of organisms (zooplankton, shrimp, crabs, small fish, etc.) that can enter the reef, allowing these organisms to reproduce more effectively. Furthermore, the artificial reef of this embodiment can more efficiently supply iron ions to the surrounding sea area through corrosion of the rebar and suspension wires in the filler. Furthermore, using crushed concrete as the filler efficiently absorbs CO2 from seawater and the atmosphere, and because it utilizes waste, there is almost no CO2 emission during the production of the artificial reef material, contributing to the prevention of global warming.

[0067] Furthermore, the artificial reef in Non-Patent Document 2 is very large and heavy, making it expensive to transport and install. In contrast, the artificial reef of this embodiment has small and lightweight reinforcing bar CP members, so no large equipment is required for transport and installation on land or at sea, thereby reducing transportation and installation costs. Furthermore, by stacking multiple artificial reefs, each made up of multiple connected reinforcing bar CP members, the same effect as a large artificial reef can be achieved, providing flexibility.

[0068] The present disclosure is not limited to the above-described embodiments, and various modifications and combinations are possible within the technical concept of the present disclosure.

[0069] 10A, 10B: Artificial fishing reef 11: Reinforced concrete CP member (reinforced concrete ball member) 60A, 60B: Pillar band 61: Band 62: Hook bolt 70: Connecting member 71: U-bolt 72: Plate

Claims

1. An artificial fishing reef comprising at least one reinforced concrete pole member cut from a reinforced concrete pole having a cavity therein, wherein the cavity of the reinforced concrete pole member is filled with a filler, and the filler includes at least one of crushed or cut pieces of at least one of cement, mortar, concrete, and reinforced concrete, a suspension wire, metal attached to the reinforced concrete pole, and fish and shells.

2. An artificial fishing reef according to claim 1, comprising a plurality of said reinforced concrete pole members, said plurality of said reinforced concrete pole members being connected together using accessories for said reinforced concrete poles.

3. An artificial fishing reef according to claim 1, comprising a plurality of said reinforced concrete pole members, each of said reinforced concrete pole members having a length of 1 m or more and less than 2.5 m, and the total weight of said plurality of connected reinforced concrete pole members being 950 kg or less.

4. A method for manufacturing an artificial fishing reef, comprising the steps of: cutting a reinforced concrete pole having an internal cavity to produce a plurality of reinforced concrete pole members; filling the plurality of reinforced concrete pole members with a filler; and connecting the plurality of reinforced concrete pole members after filling, wherein the filler includes at least one of crushed or cut pieces of at least one of cement, mortar, concrete, and reinforced concrete, suspension wires, metal attached to the reinforced concrete pole, and seafood shells.

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