Substrate for coral propagation and method for creating a coral community

Abstract

To provide a substrate for growing corals, which can be installed without any problems even in a place where strong waves hit, which is suitable for the habitation of reef-building corals, and which can be suitably applied to a method for creating a large-scale coral community, and a method for creating a coral community using the substrate. [Solution] The concrete block 2 has a covering block as its base, and a steel mesh-like adhesion base 3. The concrete block 2 has four protrusions 22 extending horizontally radially from a central portion 21 so that its planar shape is X-shaped, and each protrusion 22 has an opening 24 that penetrates from the top surface to the bottom surface, and the mesh-like adhesion base 3 is attached to the opening 24 of the protrusions 22 of the concrete block 2. A locking groove 27 is formed at the tip of each protrusion 22 of the concrete block 2, into which a sling wire can be locked.

Description

[Technical Field]

[0001] The present invention relates to a substrate for coral propagation that contributes to the conservation and regeneration of corals for the purposes of nature conservation, mitigation, biodiversity, aquaculture propagation, etc., and a method for creating coral communities using this substrate. [Background technology]

[0002] Most conventional coral propagation substrates have focused on adopting the optimal shape and material for promoting coral settlement and the growth of juvenile corals after settlement, and many of them are designed to be installed in relatively calm waters that are not significantly affected by waves or tidal currents. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-77649 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-223128 [Patent Document 3] Patent No. 4749848 Summary of the Invention [Problem to be solved by the invention]

[0004] Reef-building corals are organisms that form coral reefs, also known as natural breakwaters, and many species prefer to live in areas with strong wave impacts. It is preferable to install coral propagation substrates in locations suitable for the corals to be restored. However, as mentioned above, conventional coral propagation substrates are designed to be installed in relatively calm waters, making it difficult to install them in locations with strong wave impacts suitable for reef-building coral habitats.

[0005] Furthermore, in cases where large coral reefs have declined, a construction method in which a considerable number of coral propagation substrates are installed over a wide area is considered effective for efficiently restoring coral communities. In this case, a large amount of substrate must be transported to the installation site by workboat and installed (or relocated), requiring extensive work. After the coral communities have been restored, the substrate must also be removed or relocated (relocated). However, conventional coral propagation substrates were not designed with such work in mind, and their strength and functionality make them difficult to apply to such large-scale construction methods.

[0006] The present invention seeks to solve the problems associated with the prior art, and aims to provide a coral propagation substrate that can be installed without problems even in areas with strong waves that are suitable for the habitat of reef-building corals, and that can be suitably applied to large-scale coral colony creation methods, as well as a method of creating coral colonies using this substrate. [Means for solving the problem]

[0007] The coral growth substrate of the present invention comprises a concrete block based on a covering block and a steel mesh-like settlement base, and the concrete block has four protrusions extending horizontally radially from the center so that its planar shape is X-shaped, and each protrusion has an opening formed through it from the top surface to the bottom surface, and the mesh-like settlement base is attached to the openings of the protrusions of the concrete block.

[0008] It is preferable that the lower tip of each protrusion of the concrete block has a leg protruding downward from the bottom surface, and that the concrete block has an opening ratio of 15 to 60%.Furthermore, it is preferable that an upwardly sloping surface is formed between the horizontal top surface and the vertical side surface of the concrete block, and that this upwardly sloping surface has multiple recesses and / or protrusions.It is also preferable that the tip of each protrusion of the concrete block has a locking groove that can be used to lock a sling wire.

[0009] Furthermore, a mesh-like adhesion base made of vertical metal plates arranged in a grid pattern is preferably attached to the opening of the protruding part of the concrete block, and is preferably attached at a position lower than the top of the opening of the protruding part of the concrete block (within 50 mm below the upper edge) or within 150 to 300 mm below the upper edge of the opening.

[0010] The method for creating a coral community according to the present invention is characterized by preparing a plurality of coral growth substrates as described above, loading them onto a work boat, transporting them to an area of ​​the sea where a coral community is to be preserved or restored, and then using a crane to sling the substrates and lowering them to the seabed. In this method, a plurality of coral-grown substrates can be prepared, and a work boat equipped with a tank can be used to store seawater in the tank and transport the coral-grown substrates. After a coral community has restored in the area where the coral growth substrates were installed, the coral growth substrates can be relocated to another location. [Effects of the Invention]

[0011] The coral growth substrate of the present invention is based on covering blocks that are highly stable against waves and tidal currents, so it can be installed without problems even in areas with strong waves that are suitable for reef-building coral habitats. As a result, it is possible to more effectively conserve and restore reef-building corals than with conventional techniques. In addition, the coral growth substrate of this embodiment has a simple structure and each element has sufficient rigidity, which has the advantage of making it easy to transport, install, and remove.

[0012] According to the method for creating a coral community of the present invention, corals grow on the coral growth substrate, and as they grow, larvae spread to the surrounding sea area. As a result, coral communities can be regenerated in the sea area where the coral growth substrate is installed and in the surrounding sea area, which can contribute to the conservation and regeneration of coral reefs. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view of a coral growth substrate 1 according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing another example of the configuration of the coral growth substrate 1 shown in FIG. [Figure 3] FIG. 3 is an explanatory diagram of a method for creating a coral community according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention can be implemented as a "coral growth substrate" (first embodiment) and as a "method for creating a coral community" (second embodiment). Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0015] Figure 1 is a perspective view of a coral growth substrate 1 according to a first embodiment of the present invention. As shown in the figure, this coral growth substrate 1 is composed of concrete blocks 2 and a steel mesh substrate 3. The concrete blocks 2 are based on cover blocks used to prevent the scattering of foundation rubble placed on the seabed of ports and fishing ports, and are highly stable against waves and currents.

[0016] More specifically, this concrete block 2 has four protrusions 22 extending horizontally radially from a central portion 21 so that its planar shape is X-shaped, and a leg portion 23 projecting downward from the bottom surface is formed at the lower tip of each protrusion 22. An opening 24 is formed in the center of each protrusion 22, penetrating from the top surface to the bottom surface. In addition, an opening 25 (vertical hole) is formed in the central portion 21, penetrating from the top surface to the bottom surface. These openings 24, 25 allow the concrete block 2 to reduce the uplift pressure acting thereon, thereby enabling it to demonstrate high stability.

[0017] It is known that in order to expect an uplift pressure reduction effect in a covering block, it is effective to set the opening ratio (the ratio of the total opening area of ​​the openings to the area inside the outer contour line of the block (horizontal projection area)) to 15 to 60%. The opening ratio of the concrete block 2 of this embodiment is 25%.

[0018] Furthermore, an upwardly inclined surface is formed between the horizontal top surface and the vertical side surface of the concrete block 2. This upwardly inclined surface has a number of recesses 26 (10 to 30 mm in diameter, 5 to 10 mm in depth) formed therein. Although FIG. 1 shows recesses 26 formed on only one inclined surface, it is preferable that recesses 26 be formed on multiple upwardly inclined surfaces (or all upwardly inclined surfaces). These recesses 26 contribute to the establishment of corals and the promotion of the growth of juvenile corals after establishment. Furthermore, convex portions (5 to 10 mm in height) (not shown) may be formed on the upwardly inclined surface instead of (or in addition to) these recesses 26.

[0019] Furthermore, at the tip of each protrusion 22 of the concrete block 2, a locking groove 27 is formed to allow a sling wire to be locked.

[0020] The mesh-like settlement substrate 3 is intended to promote the settlement and growth of corals, and is attached horizontally (perpendicular to the center line of the opening 24) to the top of the opening 24 (at a height position within 50 mm below the upper edge) formed in the protruding portion 22 of the concrete block 2. This mesh-like settlement substrate 3 is made by welding steel rods (diameter approximately 5 to 15 mm) arranged in a lattice pattern (mesh opening approximately 25 to 50 mm), and contributes to the settlement of corals and the growth of juvenile corals after settlement.

[0021] Grating, which is used as a cover for road gutters, can also be used as the mesh substrate 3. Grating has a structure in which vertical metal plates are arranged in a grid pattern. Therefore, when the grating is used as the mesh substrate 3 and attached horizontally to the opening 24, it is possible to increase the vertical surface on which corals can easily grow. Furthermore, the shape of the mesh in the mesh substrate 3 is not limited to a grid (quadrilateral), and metal materials with meshes in triangular, hexagonal, other polygonal, circular, or elliptical shapes can also be used as the mesh substrate 3. These mesh substrates 3 do not impede the flow of water entering or passing through the opening 24, and therefore do not adversely affect the stability of the concrete block 2 (uplift pressure reduction effect).

[0022] In the coral growth substrate 1 of Figure 1, the mesh-like growth substrate 3 is positioned at the top of the opening 24 (within 50 mm downward from the upper edge), but as shown in Figure 2, it can also be positioned in the middle part inside the opening 24 (between a position 50 mm downward from the upper edge and a position 50 mm upward from the lower edge) (mesh-like growth substrate 3B), or it can also be positioned at the bottom of the opening 24 (within 50 mm upward from the lower edge) (mesh-like growth substrate 3C).

[0023] Strong sunlight can cause stress to corals, which can inhibit their growth. Therefore, when installing the coral growth substrate 1 in an environment where sunlight is strong (for example, a place with a relatively shallow water depth), it is preferable to place the mesh growth substrate 3 at a position lower than the top of the opening 24 (a position where shade can be provided depending on the time of day), as in the mesh growth substrates 3B and 3C shown in Figure 2. On the other hand, when installing in an environment where sunlight is not as strong (for example, a place with a relatively deep water depth), the mesh growth substrate 3 can be placed above the opening 24, as in the mesh growth substrate 3A.

[0024] Furthermore, since corals are most susceptible to predation by predators when they are in the juvenile coral stage, if the mesh-like settlement substrate 3 is placed in the middle or lower part of the opening 24 (lower than the upper part of the opening 24), as in the mesh-like settlement substrates 3B and 3C shown in Figure 2, it will be difficult for predators to find them, which is expected to have the effect of suppressing predation damage.

[0025] Furthermore, as shown in Figure 2, when the mesh-like growth substrate 3B is placed in the middle of the opening 24, it is preferable that the specific height position is lower than 150 mm below the upper edge of the opening 24 and / or higher than 300 mm below the upper edge of the opening 24 (in the range of 150 to 300 mm below the upper edge of the opening 24). Since the minimum size at which the grown corals can spawn is 150 to 300 mm, by setting the position of the mesh-like growth substrate 3 within the above range, the corals can grow inside the opening 24 until they are able to spawn, and the corals can be suitably protected from predatory organisms.

[0026] It is also possible to place multiple mesh growth substrates 3 in one opening 24. For example, as shown in Figure 2, mesh growth substrate 3A is placed in the upper part of opening 24, mesh growth substrate 3B is placed in the middle part, and mesh growth substrate 3C is placed in the lower part. With this configuration, protection from predatory organisms can be further strengthened.

[0027] Specifically, by placing the mesh-like growth substrate 3A above the opening 24, it is possible to prevent predatory organisms (fish, etc.) approaching from above from entering the inside of the opening 24, thereby protecting the corals attached to the mesh-like growth substrates 3B and 3C placed below it, and by placing the mesh-like growth substrate 3C below the opening 24, it is possible to prevent predatory organisms (crown-of-thorns starfish, sea urchins, etc.) approaching from below from entering the inside of the opening 24, thereby protecting the corals attached to the mesh-like growth substrates 3A and 3B placed above it.

[0028] Furthermore, in places where sunlight is strong, the mesh-like growth substrate 3A placed on the upper side also functions as a shading, protecting the corals attached to the mesh-like growth substrates 3B and 3C placed below it from strong light.

[0029] As mentioned above, the mesh size of the mesh substrate 3 is preferably about 25 to 50 mm, taking into consideration its function as a coral settlement substrate, but in order to prevent the intrusion of predatory organisms, it is preferable to set the mesh size of the mesh substrates 3A and 3C placed above or below the opening 24 to an appropriate value, taking into consideration the habitat conditions (species, body height, etc.) of predatory organisms in the installation area. For example, in an area where there is a concern about predation damage by Labridae fish with a body height of about 35 mm, it is effective to set the mesh size of the mesh substrates 3A and 3C to be smaller than 35 mm, so as to prevent their intrusion.

[0030] The coral growth substrate 1 of this embodiment is based on a covering block that is highly stable against waves and currents, so it can be installed without problems even in places with strong waves that are suitable for reef-building coral habitats. As a result, it can more effectively conserve and restore reef-building corals than conventional technologies. In addition, the coral growth substrate 1 of this embodiment has a simple structure and each element has sufficient rigidity, which gives it the advantage of being easy to transport, install, and remove.

[0031] Fig. 3 is an explanatory diagram of a method for cultivating a coral community according to a second embodiment of the present invention. First, a large number (for example, 100 pieces) of coral growth substrates 1 shown in Fig. 1 are prepared, loaded onto a work vessel 4, and transported to the sea area where the coral community is to be preserved and restored (the target restoration sea area). Wires 41 are sling-fastened to the coral growth substrates 1, and the substrates are lowered to the seabed 5 using a crane 42 for installation.

[0032] As described above, the coral growth substrate 1 has high stability against waves and currents, so it can be installed without problems even in places with strong waves that are suitable for the habitat of reef-building corals, and because it is formed with locking grooves 27 (see Figure 1) for locking sling wire 41, slinging work and lifting work using a crane 42 can be carried out smoothly and efficiently. Furthermore, because the coral growth substrate 1 has sufficient strength, it is suitable for large-scale transportation and installation work.

[0033] When the method for creating a coral community according to this embodiment is implemented, corals grow on the coral growth substrate 1, and as they grow, larvae spread to the surrounding sea area. As a result, it becomes possible to regenerate coral communities in the sea area where the coral growth substrate 1 is installed and in the surrounding sea area, which can contribute to the conservation and regeneration of coral reefs.

[0034] In this embodiment, the coral growth substrate 1 is installed in the sea area to be restored, but the coral growth substrate 1 with coral grown on it can also be installed in another location. In this case, it is preferable to use a work vessel 4 having an aquarium (not shown), store seawater in the aquarium, and transport the coral growth substrate 1 with coral grown on it. Furthermore, after the installation of the coral growth substrate 1, once the coral community has regenerated to a certain extent in the sea area to be restored, the coral growth substrate 1 can be relocated to another location.

[0035] Furthermore, when installing cover blocks to prevent foundation rubble placed on the seabed during the development of ports and fishing ports, the coral propagation substrate 1 can also be placed as cover blocks. In this case, in addition to the inherent disaster prevention function of port and fishing port structures, it can also be expected to function as a supply of coral larvae to the surrounding sea area. [Explanation of symbols]

[0036] 1: Coral growth substrate, 2: Concrete blocks, 3, 3A-3C: Reticulated epiphytic substrate, 4: Work boat, 5: Undersea, 21: Central part, 22:Protrusion, 23: Legs, 24,25: opening, 26: recess, 27: locking groove, 41: Wire, 42: Crane,

Claims

1. The concrete block is based on a covering block, and a steel mesh-like growth base is included. The concrete block has four protrusions extending radially from the center in the horizontal direction so that its planar shape is X-shaped, and each protrusion has an opening that penetrates from the top surface to the bottom surface. A substrate for coral growth, characterized in that a mesh-like settlement base is attached to the opening of the protruding part of a concrete block.

2. 2. The coral growth substrate according to claim 1, wherein a leg portion protruding downward from the bottom surface is formed at the lower tip of each protrusion.

3. 2. The coral growth substrate according to claim 1, wherein the concrete block has an opening rate of 15 to 60%.

4. A coral growth substrate as described in claim 1, characterized in that an upwardly inclined surface is formed between the horizontal top surface and the vertical side surface of the concrete block, and this upwardly inclined surface has multiple recesses and / or protrusions formed thereon.

5. 2. The coral growth substrate according to claim 1, wherein the tip of each protrusion of the concrete block is formed with a locking groove for locking a sling wire.

6. 2. The coral growth substrate of claim 1, wherein a mesh-like settlement base having a lattice structure of vertical metal plates is attached to the opening of the protruding portion of the concrete block.

7. 2. The coral growth substrate of claim 1, wherein the mesh-like settlement base is attached at a position lower than the top of the concrete block and within 50 mm below the upper edge of the opening of the protruding portion of the concrete block.

8. 2. The coral growth substrate of claim 1, wherein the mesh-like settlement base is attached within a range of 150 to 300 mm below the upper edge of the opening of the protruding portion of the concrete block.

9. A method for creating a coral community, comprising the steps of: preparing a plurality of coral propagation substrates according to any one of claims 1 to 8; loading them onto a work boat; transporting them to an area of ​​the sea where a coral community is to be preserved or restored; attaching a wire to the substrate; and lowering the substrates to the seabed using a crane for installation.

10. We prepared several coral-grown substrates, 10. The method for creating a coral community according to claim 9, characterized in that a work vessel having an aquarium is used, seawater is stored in the aquarium, and a coral propagation substrate on which corals have grown is stored and transported.

11. 10. The method for creating a coral community according to claim 9, wherein after the coral community has regenerated in the sea area where the coral growth substrates have been installed, the coral growth substrates are relocated to another location.

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