Spiny lobster breeding reef and spiny lobster breeding method

Abstract

To provide a lobster growth reef which is a house of young lobsters and on which parent lobsters can live continuously, and a lobster growing method using the lobster growth reef.SOLUTION: A lobster growth reef of the invention comprises an upper concrete block and a lower concrete block which are overlapped vertically and coupled. The upper concrete block comprises: a top surface part; and a side wall part extending downward from an outer peripheral edge of the top surface part, and forming an internal space. On at least one outside surface of the side wall part, there is formed a recess group comprising, a plurality of kinds of recesses, the recesses having a different inner diameter and depth dimension, and there is formed an opening for forming an opening for communicating the internal space with an external space. The lower concrete block comprises: a main body part; and a protrusion part protruded upward from the top surface of the main body part. The protrusion part has on its top, a protruded top part, and the protruded top part is positioned below an inside surface of the top surface part and above the opening.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a spiny lobster breeding reef and a method for cultivating spiny lobsters using the spiny lobster breeding reef. [Background technology]

[0002] In order to secure and increase spiny lobster resources, it is important to ensure that the postlarvae, which are the first stage of the lobster returning from offshore to the coast after spawning, settle on the bottom, and that the postlarvae and juvenile shrimp can live safely and grow into parent shrimp.

[0003] It was previously assumed that postlarvae and juvenile shrimp live in seaweed and other hiding places. However, in recent years, it has been reported that postlarvae and juvenile shrimp hide overwhelmingly in cylindrical depressions formed on the surface of reefs near seaweed, and that hiding in a depression of a size that fits their body perfectly increases their chances of survival. For this reason, various spiny lobster breeding reefs have been proposed that have multiple types of depressions with different inner diameters and depths so that postlarvae and juvenile shrimp can change habitats as they grow.

[0004] For example, Patent Document 1 discloses a lobster propagation reef of this kind, which has a main body having at least one side wall with multiple types of recesses formed therein, placed on a base having a surface larger than the bottom surface of the main body. Patent Document 2 discloses a lobster propagation reef with multiple types of recesses formed on the side surface and a mounting portion for attaching seaweed on the top located above the side surface. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-90639 A [Patent Document 2] JP 2013-172651 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the spiny lobster breeding reefs described in Patent Documents 1 and 2 provide habitats for postlarvae and juvenile shrimp for 1 to 2 years after hatching, so when the juvenile shrimp grow and become parent shrimp, they need to find a new habitat. Therefore, even if juvenile shrimp can be multiplied, there are places where the catch of spiny lobsters does not increase due to the movement of parent shrimp, and there has been a demand for spiny lobster breeding reefs that can increase the catch of spiny lobsters.

[0007] The present invention has been made in view of such circumstances, and aims to provide a spiny lobster breeding reef that is a habitat for postlarvae and juvenile shrimp and in which parent shrimp can continue to live, and a spiny lobster breeding method using the spiny lobster breeding reef. [Means for solving the problem]

[0008] The spiny lobster breeding reef according to the present invention is a spiny lobster breeding reef made of concrete blocks, the concrete blocks being composed of an upper concrete block and a lower concrete block which are joined together by being stacked one on top of the other, the upper concrete block having an upper surface and a side wall portion extending downward from the outer periphery of the upper surface and forming an internal space, at least one outer surface of the side wall portion being provided with a group of recesses having a plurality of types of recesses with different inner diameters and depth dimensions for postlarvae and larvae to relocate as they grow, An opening is provided in the lower concrete block, which forms an opening connecting the internal space with the external space, and the lower concrete block comprises a main body on whose top surface the upper concrete block is stacked, and a protruding portion protruding upward from the top surface of the main body and configured to be accommodated in the internal space of the upper concrete block, the protruding portion having a protruding top at its top, and the protruding top of the lower concrete block being positioned below the inner surface of the top portion of the upper concrete block and above the opening in the side wall portion.

[0009] The lobster breeding reef has a group of recesses having a plurality of types of recesses with different inner diameters and depths on at least one outer surface of the side wall, so that postlarvae and juvenile shrimp can move to new habitats as they grow, and therefore can provide habitats for postlarvae and juvenile shrimp. When the upper concrete block and the lower concrete block are stacked and joined together, a gap is formed between the upper concrete block and the lower concrete block, because the protruding top of the lower concrete block is lower than the inner surface of the upper surface of the upper concrete block. And, because the protruding top of the lower concrete block is located higher than the opening of the side wall, it becomes difficult to see the parent shrimp that has entered the gap from the outside of the lobster breeding reef. In other words, the parent shrimp can hide from predators, so that the parent shrimp do not need to look for a new habitat and can continue to live in the lobster breeding reef.

[0010] The spiny lobster breeding reef of the present invention may further include a base block below the concrete block, the base block having at least three legs extending downward and configured to be able to be grounded by the legs.

[0011] With such a configuration, the spiny lobster breeding reef can be stably installed even on an uneven seabed or sandy ground.

[0012] In the spiny lobster breeding reef according to the present invention, the lower concrete block and the base block may be integrally formed.

[0013] With such a configuration, the spiny lobster breeding reef does not require the work of fixing the lower concrete block and the base block with anchors, pins, etc. Also, it is possible to prevent the anchors, pins, etc. from coming off and breaking the connection between the lower concrete block and the base block.

[0014] In the spiny lobster breeding reef according to the present invention, the protruding top may be formed in a flat shape.

[0015] With such a structure, the spiny lobster breeding reef allows parent shrimp to easily take up residence on the top of the protruding structure, thereby increasing the rate at which parent shrimp settle.

[0016] In the spiny lobster breeding reef according to the present invention, a mounting portion for mounting seaweed may be provided on the outer surface of the top portion of the upper concrete block.

[0017] The lobster breeding reef, with such a structure, can encourage the swimming postlarvae to catch on the seaweed and settle on the lobster breeding reef. Also, the small marine organisms living on the seaweed become food for the postlarvae and the juvenile shrimp, so that the settlement and settlement of the postlarvae and the juvenile shrimp can be promoted.

[0018] In the spiny lobster breeding reef according to the present invention, the concrete block may be a hardened body obtained by hardening a concrete composition containing recycled raw materials.

[0019] The lobster breeding reef, with such a configuration, can reduce the environmental load.

[0020] In the spiny lobster breeding reef according to the present invention, the recycled raw material may be wood biomass ash.

[0021] The lobster breeding reef, having such a structure, can reuse wood biomass ash that has conventionally been treated as industrial waste, and therefore can further reduce the environmental load.

[0022] In the method for cultivating spiny lobsters according to the present invention, spiny lobsters are cultivated using the spiny lobster breeding reef described above.

[0023] The method for cultivating spiny lobsters, having such a constitution, can cultivate postlarvae and juvenile shrimps as well as parent shrimps. Effect of the Invention

[0024] According to the present invention, it is possible to provide a spiny lobster breeding reef that is a habitat for postlarvae and juvenile shrimp and in which parent shrimp can continue to live, and a spiny lobster breeding method using the spiny lobster breeding reef. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a front view of a spiny lobster breeding reef 1 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing the II-II section of the spiny lobster breeding reef 1 of FIG. [Diagram 3] FIG. 3 is an exploded perspective view of a concrete block 10 constituting the spiny lobster breeding reef 1 according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a front view of a spiny lobster breeding reef 1 according to a second embodiment of the present invention. [Diagram 5] FIG. 5 is a cross-sectional view showing the VV section of the spiny lobster breeding reef 1 of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, the spiny lobster breeding reef 1 and the spiny lobster cultivating method according to this embodiment will be described with reference to the drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and the description thereof will not be repeated. In this specification, the puerulus larvae (commonly known as glass shrimp) at the stage before growing into juvenile shrimp are called "postlarvae", juvenile spiny lobsters between 1 and 2 years after hatching are called "juvenile shrimp", and adult spiny lobsters 2 years after hatching are called "parent shrimp".

[0027] [First embodiment] <Spiny Lobster Reef> Hereinafter, the spiny lobster propagation reef 1 according to the first embodiment will be described. FIG. 1 is a front view of the spiny lobster propagation reef 1 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing the II-II cross section of the spiny lobster propagation reef 1 in FIG. 1. FIG. 3 is an exploded perspective view of a concrete block 10 constituting the spiny lobster propagation reef 1 according to the first embodiment of the present invention. As shown in FIG. 1, the spiny lobster propagation reef 1 according to the first embodiment comprises a concrete block 10 composed of an upper concrete block 2 and a lower concrete block 3 which are joined together by being stacked one on top of the other, and a base block 4 located below the concrete block 10.

[0028] As shown in Figs. 1 and 3, the concrete block 10 is composed of an upper concrete block 2 and a lower concrete block 3 located below the upper concrete block 2. The concrete block 10 is rectangular when viewed from above, and is formed in a prismatic shape. The size of the concrete block 10 is not particularly limited, and for example, the length of one side of the rectangle (lengths in the X and Y directions in Fig. 3) can be 1 m or more and 4 m or less, and the height (length in the Z direction in Fig. 3) can be 1 m or more and 4 m or less. Note that the top view refers to a state seen from above in the vertical direction (Z direction in Fig. 1).

[0029] The upper concrete block 2 includes an upper surface portion 21 and a side wall portion 22 that extends downward from the outer periphery of the upper surface portion 21 and forms an internal space. The upper concrete block 2 is formed in a rectangular column shape with an open bottom surface when viewed from above.

[0030] The upper surface portion 21 is formed in a rectangular shape when viewed from above. Nine mounting portions 23 for mounting seaweed are provided at predetermined intervals on the outer surface of the upper surface portion 21, and seaweed can be grown thereon as a base for the postlarvae to settle and as a feeding ground for the postlarvae and juvenile shrimp.

[0031] The side wall portion 22 is formed by extending downward from the outer periphery of the upper surface portion 21. Specifically, the side wall portion 22 is composed of four side portions 24 extending downward from the four edges constituting the outer periphery of the upper surface portion 21. The four side portions 24 are connected to each other to form an internal space with an open lower portion. All outer surfaces of the side wall portion 22 (i.e., the outer surfaces of each side portion 24) are provided with a group of recesses 26 having a plurality of types of recesses 25 with different inner diameters and depth dimensions for postlarvae and larvae shrimp to relocate according to their growth. In addition, an opening 27 is provided at the lower end of each side portion 24 constituting the side wall portion 22, forming an opening that communicates between the internal space and the external space.

[0032] The recess group 26 has a plurality of types of recesses 25 with different inner diameters and depths. Specifically, a plurality of types of recesses 25 with different inner diameters and depths are randomly provided on a plate having a rectangular shape when viewed from the front. The plates are arranged at predetermined intervals, three per plate, on each outer surface of the side wall portion 22 (i.e., the outer surface of each side portion 24).

[0033] The recess 25 extends horizontally (the X direction in FIG. 1 and the Y direction in FIG. 3) from the surface of the recess group 26 toward the internal space, and is formed in a cylindrical shape with a bottom. The inner diameter of the recess 25 is preferably 5 mm or more and 50 mm or less, and more preferably 8 mm or more and 46 mm or less. The depth of the recess 25 is preferably 15 mm or more and 150 mm or less, and more preferably 22 mm or more and 131 mm or less.

[0034] The inner diameter and depth of the recess 25 are designed to have the following eight sizes based on the carapace length of the postlarvae and juvenile shrimp. 1st stage: Inner diameter 8mm to less than 12mm, depth 22mm to less than 35mm Second stage: Inner diameter 12mm to less than 15mm, depth 35mm to less than 40mm 3rd stage: Inner diameter 15mm to less than 17mm, depth 40mm to less than 47mm 4th stage: Inner diameter 17mm to less than 21mm, depth 47mm to less than 55mm 5th stage: Inner diameter 21mm to less than 24mm, depth 55mm to less than 64mm 6th stage: Inner diameter 24mm to less than 29mm, depth 64mm to less than 78mm 7th stage: Inner diameter 29mm to less than 36mm, depth 78mm to less than 94mm 8th stage: Inner diameter 36mm to 46mm, depth 94mm to 131mm

[0035] The opening 27 is formed in a rectangular shape at the lower end of each side portion 24. The height of the opening 27 (the length in the Z direction in FIG. 1) is 3 cm to 30 cm, and preferably 10 cm to 20 cm. This allows parent shrimp to enter the internal space, and makes it difficult to see the internal space from outside the spiny lobster breeding reef 1.

[0036] As shown in Figure 2, an internal space is formed inside the upper concrete block 2, and the inner surface of each side portion 24 has an inclined portion 29 that slopes toward the center of the inner surface 28 of the top portion 21. By providing the inclined portion 29, a space suitable as a habitat for parent shrimp can be formed.

[0037] 3, the lower concrete block 3 comprises a main body 31 on whose top surface the upper concrete block 2 is placed, and a protruding portion 32 that protrudes upward from the top surface of the main body 31 and is configured to be able to be accommodated in the internal space of the upper concrete block 2. The lower concrete block 3 is formed in the shape of a rectangular column when viewed from above. The outer peripheries of the lower concrete block 3 and the upper concrete block 2 overlap when viewed from above.

[0038] The protruding parts 32 are disposed at a predetermined distance from the outer periphery toward the center of the main body 31 in a top view. The protruding parts 32 are formed in a quadrangular pyramid shape in a front view. The height of the protruding parts 32 (the length in the Z direction in FIG. 3) is 3 cm or more and 30 cm or less, and preferably 10 cm or more and 20 cm or less, from the viewpoint of increasing the settlement rate of the parent shrimp. A protruding top part 33 formed in a flat shape is provided at the top of the protruding parts 32.

[0039] The protruding top 33 is located below the inner surface 28 of the top surface 21 of the upper concrete block 2 and above the opening 27 of the side wall 22. In other words, a gap in which parent shrimp can live exists between the inner surface 28 of the top surface 21 of the upper concrete block 2 and the protruding top 33, and the structure is such that the gap is difficult to see from the outside.

[0040] As shown in FIG. 1, the base block 4 is located below the lower concrete block 3, and the lower concrete block 3 and the base block 4 are integrally formed. The base block 4 has at least three legs 41 extending downward, and is configured so that the legs 41 can be grounded. Specifically, the base block 4 includes a base main body 42 and three legs 41 provided below the base main body 42. The base main body 42 is formed in a rectangular column shape that is a scalene hexagon formed by virtually cutting three corners of an equilateral triangle with equal sizes when viewed from above. The legs 41 are formed by extending downward from three non-adjacent side surfaces of the base main body 42 that have small areas.

[0041] The spiny lobster breeding reef 1 is formed by joining the lower concrete block 3 formed integrally with the base block 4 and the upper concrete block 2. Specifically, after the base block 4 and the lower concrete block 3 are formed integrally, the upper concrete block 2 is placed on the upper surface of the lower concrete block 3 and joined. In this way, by joining the lower concrete block 3 and the upper concrete block 2 as separate bodies, a gap that makes it difficult to see the parent shrimp from the outside of the spiny lobster breeding reef 1 can be formed. As a method for forming the base block 4 and the lower concrete block 3 integrally, for example, a method is included in which the lower concrete block 3 made in advance is placed in a formwork for making the base block 4, and then concrete is poured and hardened to integrate them. In addition, as a method for joining the upper concrete block 2 and the lower concrete block 3, for example, joining methods using bolts and nuts, joining with anchors, joining with fixing chucks and pins, etc. are included. Among these, the joining method is preferably a joining method using fixing chucks and pins from the viewpoint of ease of joining and reliability.

[0042] The spiny lobster breeding reef 1 is preferably a hardened body obtained by hardening a concrete composition containing recycled raw materials. Examples of recycled raw materials include wood biomass ash, coal ash, slag, recycled aggregate, casting sand, etc. Among these, the recycled raw material is preferably wood biomass ash.

[0043] The spiny lobster breeding reef 1 according to this embodiment has a group of recesses 26 on at least one outer surface of the side wall 22, which has a plurality of types of recesses 25 with different inner diameters and depths for postlarvae and juvenile shrimp to move to as they grow, and therefore can provide a habitat for postlarvae and juvenile shrimp. When the upper concrete block 2 and the lower concrete block 3 are stacked and joined together, a gap is formed between the upper concrete block 2 and the lower concrete block 3, since the protruding top 33 of the lower concrete block 3 is lower than the inner surface 28 of the upper surface 21 of the upper concrete block 2. Since the protruding top 33 of the lower concrete block 3 is located above the opening 27 of the side wall 22, it becomes difficult to confirm the appearance of parent shrimp that has entered the gap from the outside of the spiny lobster breeding reef 1. In other words, the parent shrimp can hide from predators, so that the parent shrimp does not need to search for a new habitat and can continue to live on the spiny lobster breeding reef 1.

[0044] The spiny lobster breeding reef 1 of this embodiment has a base block 4 below a concrete block, and the base block 4 has at least three legs 41 extending downward. The legs 41 are configured to be able to ground, so that the lobster breeding reef 1 can be stably installed even on an uneven seabed or sandy area.

[0045] In the spiny lobster breeding reef 1 according to this embodiment, the lower concrete block 3 and the base block 4 are integrally formed, which eliminates the need for fixing the lower concrete block 3 and the base block 4 with anchors, pins, etc. Also, it is possible to prevent the anchors, pins, etc. from coming loose and causing the connection between the lower concrete block 3 and the base block 4 to be broken.

[0046] In the spiny lobster breeding reef 1 according to this embodiment, the protruding top portion 33 is formed in a flat shape, so that parent shrimp can easily take up residence on the protruding top portion 33, and the settlement rate of parent shrimp can be increased.

[0047] In the spiny lobster breeding reef 1 according to this embodiment, the outer surface of the upper surface portion 21 of the upper concrete block 2 is provided with a mounting portion 23 for mounting seaweed, so that the swimming postlarvae can be caught by the seaweed and encouraged to settle on the spiny lobster breeding reef 1. In addition, small marine organisms living on the seaweed become food for the postlarvae and juvenile shrimp, which promotes the settlement and settlement of the postlarvae and juvenile shrimp.

[0048] The spiny lobster breeding reef 1 according to this embodiment can reduce the environmental load because the concrete blocks 10 are hardened bodies obtained by hardening a concrete composition containing recycled raw materials.

[0049] The spiny lobster breeding reef 1 of this embodiment uses wood biomass ash as a recycled raw material, and therefore can reuse wood biomass ash that has traditionally been treated as industrial waste, thereby further reducing the environmental burden.

[0050] <How to raise spiny lobsters> Next, a spiny lobster cultivating method according to the present embodiment will be described. In the spiny lobster cultivating method according to the present embodiment, the spiny lobster cultivating method uses the spiny lobster breeding reef 1 described above to cultivate spiny lobsters.

[0051] Specifically, the spiny lobster propagation reef 1 is first installed on the seabed in or around a seaweed colony (seaweed bed) facing the open sea, which is the natural habitat of juvenile lobsters. By installing it in this manner, the seaweed on the mounting portion 23 can grow relatively easily. In order to avoid movement, tipping, and damage to the concrete block 10, the spiny lobster propagation reef 1 is preferably installed in a water depth zone that is unlikely to be affected by waves during typhoons and in a location shallower than 20 m in depth. In addition, after being installed on the seabed, it is preferable to continue using the spiny lobster propagation reef 1 without moving it.

[0052] Next, the postlarvae, juvenile shrimp, and parent shrimp are raised on the spiny lobster breeding reef 1 installed on the seabed. When the spiny lobster breeding reef 1 is installed on the seabed, the postlarvae cling to the seaweed on the attachment part 23, and find a recess 25 of a size that fits their body perfectly among the recesses 26 scattered around the seaweed, and live there. Then, each time the postlarvae molt and grow into a large juvenile shrimp, they move to a larger recess 25 (a larger recess 25 that fits their body perfectly). Since the recesses 26 are provided with multiple types of recesses 25, the juvenile shrimp can find a larger recess 25 among the recesses 26. This makes it possible to shorten the distance that the juvenile shrimp must travel as they grow, and increases the chances that the juvenile shrimp will survive.

[0053] When the baby shrimps grow to become parent shrimps, they can move to the gap between the upper concrete block 2 and the lower concrete block 3. This allows the parent shrimps to remain and grow on the spiny lobster breeding reef 1. Note that parent shrimps that have grown outside the spiny lobster breeding reef 1 can also be grown on the spiny lobster breeding reef 1 before the baby shrimps on the spiny lobster breeding reef 1 grow to become parent shrimps.

[0054] The spiny lobster cultivation method according to the present embodiment uses the spiny lobster breeding reef 1 described above to provide a habitat for the spiny lobster according to its growth stage, and also provides seaweed that serves as a bottom attachment site for the postlarvae and a feeding site for the postlarvae and the juvenile shrimp, thereby cultivating the postlarvae and the juvenile shrimp as well as the parent shrimp.

[0055] [Second embodiment] Hereinafter, the second embodiment of the spiny lobster breeding reef 1 according to the present invention will be described with reference to the drawings, focusing on the differences from the first embodiment. In the following drawings, the same or corresponding parts are designated by the same reference characters, and the description thereof will not be repeated.

[0056] Fig. 4 is a front view of a spiny lobster breeding reef 1 according to a second embodiment of the present invention. Fig. 5 is a cross-sectional view showing a VV cross section of the spiny lobster breeding reef 1 of Fig. 4. As shown in Fig. 5, an internal space is formed inside the upper concrete block 2, and the inner surface of each side portion 24 has an inclined portion 29 that inclines toward the center of the inner surface 28 of the upper surface portion 21. The inclined portion 29 of the second embodiment is formed with a gentler gradient than the inclined portion 29 of the first embodiment.

[0057] Moreover, the protruding portion 32 of the lower concrete block 3 is disposed at a predetermined distance from the outer periphery of the main body portion 31 toward the center, and is formed in a quadrangular pyramid shape when viewed from the front. A flat protruding top portion 33 is provided at the top of the protruding portion 32. In the second embodiment, the area of ​​the protruding top portion 33 is smaller than that of the protruding portion 32 of the first embodiment, and the inclination of the protruding portion 32 toward the protruding top portion 33 is formed with a gentle gradient.

[0058] In the spiny lobster breeding reef 1 according to the second embodiment of the present invention, the inclination of the protruding portion 32 toward the protruding top portion 33 is formed gently, so that the parent shrimp can easily reach the area where it is difficult to see the parent shrimp. As a result, the settlement rate of the parent shrimp can be increased.

[0059] [Other embodiments] The first and second embodiments of the present invention (hereinafter, these embodiments are collectively referred to as the present embodiment) have been described above, but the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. In addition, it goes without saying that the configurations and methods of the above and following embodiments may be arbitrarily adopted and combined (the configurations and methods of one embodiment may be applied to the configurations and methods of other embodiments).

[0060] For example, in the above embodiment, the upper concrete block 2 and the lower concrete block 3 are both formed in a rectangular prism shape when viewed from above. Furthermore, the outer peripheries of the lower concrete block 3 and the upper concrete block 2 overlap when viewed from above. However, the present invention is not limited to this configuration, and the upper concrete block 2 and the lower concrete block 3 may be formed in a rectangular prism shape having a polygonal shape other than a rectangle when viewed from above, or may be formed in a circular cylinder shape when viewed from above. Furthermore, as long as they can be joined by stacking them one above the other, the outer peripheries of the upper concrete block 2 and the lower concrete block 3 do not have to overlap when viewed from above.

[0061] In the embodiment, nine mounting portions 23 are provided at predetermined intervals on the upper surface portion 21. However, the present invention is not limited to this configuration, and the arrangement and number of mounting portions 23 can be changed as appropriate.

[0062] In the above embodiment, the recess group 26 is provided on the outer surface of the side wall portion 22 of the upper concrete block 2. However, the present invention is not limited to this configuration, and the recess group 26 may be provided on the side surface of the main body portion 31 of the lower concrete block 3 or on the side surface of the base main body portion 42 of the base block 4 from the viewpoint of increasing the number of juvenile shrimp that settle.

[0063] In the above embodiment, the recess groups 26 are provided on all outer surfaces of the side wall portion 22 (i.e., the outer surface of each side portion 24). The recess groups 26 are arranged in groups of three on each outer surface of the side wall portion 22 (i.e., the outer surface of each side portion 24). However, the present invention is not limited to this configuration, and the recess groups 26 may be provided on at least one outer surface of the side wall portion 22 (i.e., the outer surface of at least one side portion 24). The outer surface on which the recess groups 26 are arranged and the number of recess groups 26 to be arranged can be changed as appropriate. For example, six recess groups 26 may be arranged on each outer surface of the side portions 24 arranged opposite each other.

[0064] In the embodiment, the recess group 26 is formed by providing the recesses 25 on a plate having a square shape when viewed from the front, and the plate is disposed on each outer surface of the side wall portion 22. The recesses 25 are formed so as to extend from the surface of the recess group 26 toward the internal space along the horizontal direction. However, the present invention is not limited to this configuration, and the method of forming the recess group 26 and the recesses 25 can be appropriately changed. For example, the recesses 25 may be formed by directly drilling holes in the outer surface of the side wall portion 22 with a drill or the like, or may be formed by providing a protrusion corresponding to the recesses 25 on the formwork when the upper concrete block 2 is poured. The direction in which the recesses 25 extend from the surface of the recess group 26 toward the internal space may be a direction slightly upward with respect to the horizontal direction.

[0065] In the embodiment, the opening 27 is formed in a rectangular shape at the lower end of each side portion 24. However, the present invention is not limited to this configuration, and the opening 27 may be formed, for example, in two adjacent side portions 24. The shape of the opening 27 may be a circle, an ellipse, a polygon, or the like.

[0066] In the embodiment, the inclined portion 29 is formed on the inner surface of each side portion 24. However, the present invention is not limited to this configuration, and the inclined portion 29 may be formed only on the inner surface of some of the side portions 24, or the inclined portion 29 may not be formed.

[0067] In the above embodiment, the protruding portion 32 is formed in a quadrangular pyramid shape when viewed from the front. The protruding top 33 is formed in a flat shape. However, the present invention is not limited to this configuration, and the protruding portion 32 may be formed in a polygonal pyramid shape other than a quadrangle. The protruding top 33 may be, for example, a curved surface in which unevenness is formed on the flat protruding top 33.

[0068] In the above embodiment, the base body 42 is formed in a rectangular column shape that is a scalene hexagon when viewed from above. The base block 4 has three legs 41. However, the present invention is not limited to this configuration, and the shape of the base body 42 can be changed as appropriate. For example, the shape of the base body 42 may be formed in a cylindrical shape. The base block 4 may have four or more legs 41.

[0069] Also, in the above embodiment, the lower concrete block 3 and the base block 4 are integrally formed. However, the present invention is not limited to this configuration, and the lower concrete block 3 and the base block 4 may be formed as separate bodies. In this case, the upper concrete block 2 and the lower concrete block 3 may be joined to form the concrete block 10, and then the concrete block 10 and the base block 4 may be joined, or the lower concrete block 3 and the base block 4 may be joined, and then the upper concrete block 2 may be joined.

[0070] In the above embodiment, the lobster breeding reef 1 is a hardened body of a concrete composition containing recycled raw materials. However, the present invention is not limited to this configuration, and the concrete block 10 may be a hardened body of a concrete composition containing recycled raw materials, and the base block 4 and the concrete block 10 may be hardened bodies of concrete compositions containing different raw materials. [Explanation of symbols]

[0071] 1. Lobster breeding reef 2 Upper concrete block 3 Lower concrete block 4 Pedestal Block 10. Concrete Block 21 Top part 22 Side wall 23 Mounting part 25 Recess 26 Recesses 27 Opening 31 Body part 32 Protruding part 33 Protruding top 41 Leg

Claims

1. A spiny lobster breeding reef made of concrete blocks, The concrete block is composed of an upper concrete block and a lower concrete block which are stacked and joined together, The upper concrete block has an upper surface and a side wall extending downward from the outer periphery of the upper surface and forming an internal space, and at least one outer surface of the side wall is provided with a group of recesses having a plurality of types of recesses with different inner diameters and depths for postlarvae and larvae to relocate as they grow, and an opening is provided to form an opening that communicates with the internal space and an external space, The lower concrete block includes a main body on which the upper concrete block is stacked, and a protruding portion that protrudes upward from the top surface of the main body and is configured to be accommodated in the internal space of the upper concrete block, and the protruding portion has a protruding top portion at its top, A lobster breeding reef, wherein the protruding top of the lower concrete block is located below the inner surface of the upper surface of the upper concrete block and above the opening of the side wall portion.

2. Further, a base block is provided below the concrete block, 2. The lobster propagation reef according to claim 1, wherein the base block has at least three legs extending downward and is configured so as to be able to be grounded by the legs.

3. 3. The lobster accretion reef of claim 2, wherein said lower concrete block and said base block are integrally formed.

4. The lobster breeding reef according to any one of claims 1 to 3, wherein the protruding top is formed in a flat shape.

5. The lobster breeding reef according to any one of claims 1 to 4, wherein an attachment portion for attaching seaweed is provided on the outer surface of the upper surface portion of the upper concrete block.

6. The lobster breeding reef according to any one of claims 1 to 5, wherein the concrete block is a hardened body obtained by hardening a concrete composition containing recycled raw materials.

7. The lobster breeding reef according to claim 6, wherein the recycled material is woody biomass ash.

8. A method for cultivating spiny lobsters, comprising cultivating spiny lobsters using the spiny lobster breeding reef according to any one of claims 1 to 7.

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