JPH10113091A - Fishing bank for osteraceae - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently grow Zosteraceae on the upper surface of a fishing bank block. SOLUTION: For this fishing bank for the Zosteraceae, the peripheral wall 2 of a prescribed height capable of passing through an ocean current but consuming the energy of movement at the time of passing is provided around the upper surface of the fishing bank block 1. On the upper surface of the fishing bank block 1 on the inner side of the peripheral wall 2, a sandy mud mat 3 for which sandy mud is put in a bag provided with countless voids is disposed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reef for breeding eelgrass on the seabed.

[0002]

2. Description of the Related Art Eelgrass grounds are a marine flowering plant (seaweed) community, where many fishes have settled and migrated, and thus have been used as important fishing grounds since ancient times. However, eelgrass beds have been rapidly decreasing due to environmental changes such as coastal development. In contrast, fishery officials, test sites, etc.
Test research is being conducted on the recovery of eelgrass grounds. However, the reality is that no effective technology has yet been established.

By the way, the eelgrass ground where eelgrass thrives realizes the following natural environment. The amount of dissolved oxygen increases. The overgrown plants reduce the flow of seawater and create shade, thus improving the living environment for juvenile fish. The surface of the grass and the space between the grasses serve as a growth substrate for small animals, and serve as a feeding place for fish using these as feed and also as a spawning place. Utilizes nutrients dissolved in the process of plant growth.
Also, the dead plants accumulate on the sea floor and are decomposed, and become the center of the plant chain of organisms that grow on the eelgrass beds. Since eelgrass grows in sand mud, the plant prevents sand and mud from moving in the ocean current.

[0004] As described above, the eelgrass ground can realize a comfortable habitat for living things in the sea. Therefore, if an eelgrass ground can be realized on the sea floor, the fishing ground environment can be significantly improved.

[0005] By the way, eelgrass does not proliferate in all the environments on the sea floor, but grows in an extremely limited environment. The environment is as follows. It thrives at a depth of about 2 to 5 meters. If the water depth is too deep, the sun's rays are weakened and photosynthesis is weakened. The light amount is desirably 20% or more of the sea surface. If the water depth is too shallow, the effect of the waves will be great, and stable breeding will not be possible. Seabed soil Sand mud with an average particle size of 0.5 mm. Although sand mud having a particle size of 3 mm or more may grow, a large amount of eelgrass does not propagate. Ocean current 10 cm / sec or less. The rhizome is 10 cm from the surface of the seabed
In other words, the rhizome does not penetrate deep into the seabed, so if the current is fast, it will be swept away.

[0006]

The present inventor has developed a fishing reef in which a concave portion is provided on the upper surface of a fishing reef block and the concave portion is filled with sand and mud as a reef satisfying this condition. In this reef block, a peripheral wall made of concrete was provided around the concave portion in order to reduce the flow velocity of the ocean current flowing on the upper surface of the concave portion. Sand and mud are filled inside the surrounding wall to create a comfortable environment for eelgrass. However, the reef with this structure was unable to efficiently grow eelgrass, and there was also a problem that sand and mud gradually disappeared and disappeared. The reason why eelgrass cannot grow efficiently is that the surrounding wall cannot sufficiently reduce the speed of the current. The surrounding wall is thought to be able to effectively stop the flow of the ocean current, but in fact, a vortex (Karman vortex street) was generated on the downstream side of the surrounding wall, and this caused the seawater on the upper surface of the sand and mud to flow. The effect of the vortex can be reduced by increasing the peripheral wall. However, when a high peripheral wall is provided around the periphery, the shadow of the concave portion filled with sand and mud becomes large, and the light quantity decreases, so that photosynthesis cannot be performed sufficiently. For this reason, eelgrass cannot grow efficiently. If the surrounding wall is lowered to increase the amount of light, the seawater flows faster and the habitat of eelgrass deteriorates. For this reason, eelgrass cannot prosper on a fishing reef where sand and mud are provided in a concave portion provided inside the peripheral wall.

[0007] The present invention has been developed for the purpose of further solving this drawback. An important object of the present invention is to provide a fishing reef capable of efficiently growing eelgrass on the upper surface of a fishing reef block.

[0008]

Means for Solving the Problems A fishing reef for eelgrass of the present invention has the following constitution in order to achieve the above-mentioned object.
The reef is provided with a peripheral wall 2 having a predetermined height around the upper surface of the reef block 1, through which an ocean current can pass but energy of motion is consumed when passing. Furthermore, the reef of the present invention
Inside the peripheral wall 2, on the upper surface of the fishing reef block 1, there is provided a sand / mud mat 3 in which sand / mud is put in a bag having countless voids.

Further, in the fishing reef according to the second aspect of the present invention, a water passage portion is provided below the sand and mud mat 3 in the fishing reef block 1 on which the sand and mud mat 3 is placed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. However, the following examples illustrate fishing reefs for embodying the technical idea of the present invention, and the present invention does not specify fishing reefs as follows.

Further, in this specification, in order to make it easier to understand the claims, the numbers corresponding to the members shown in the embodiments are set forth in the “claims” and “ In the column of “means”. However, the members described in the claims are not limited to the members of the embodiments.

The fishing reef shown in FIG. 1 and FIG.
A peripheral wall 2 is provided on the upper surface of the vehicle, and a sand / mud mat 3 is laid inside the peripheral wall 2. The reef block 1 is composed of a hollow box-shaped reef main body 1A and a rectangular medium frame 1B placed on the reef main body 1A. The reef main body 1A and the medium frame 1B are made of reinforced concrete.

The reef main body 1A is provided with a window 4 on the side surface in a hollow shape in order to make the inside thereof a habitat for fish. Further, the reef main body 1A has an open top and bottom. The reason why the upper surface is opened is to open the bottom surface of the sand / mud mat 3 to be placed so that seawater can pass through the sand / mud mat 3. The size of the reef body 1A is, for example, 1
The side is 50 cm to 5 m, preferably 70 cm to 3 m, and optimally 80 cm to 2 m. Medium frame 1B on reef main body 1A
The reef block 1 on which the is placed is a medium frame 1B in the reef main body 1A.
The water depth can be adjusted. This is because the medium frame 1B can be installed at a higher position from the sea bottom with the reef main body 1A. Therefore, the size and especially the height of the fishing reef main body 1A are designed so that the culture medium frame 1B can be installed at an optimum water depth for the growth of eelgrass. Therefore, the reef block 1 in which the medium frame 1B is placed on the reef main body 1A can grow eelgrass at an optimum water depth, and can provide a habitat for fish below the eelgrass.

As shown in FIGS. 1 and 2, the medium frame 1B
It is formed in a rectangular shape having the same outer shape as the reef main body 1A so that it can be placed on the reef main body 1A and its outer surface can be made the same plane. The medium frame 1B has a sectional view of FIG. 2, a plan view of FIG.
As shown in the side view of FIG. The sand / mud mat 3 is placed horizontally in the hollow part. The bottom surface of the hollow portion fixes a water-permeable bottom member 5 on which the sand / mud mat 3 placed thereon is placed. Further, on the upper surface of the hollow portion, a holding rod 6 for preventing floating is fixed so that the sand / mud mat 3 laid there is not raised. For example, a 6 mmφ reinforcing bar is
A fixed stitch can be used so as to form a stitch of m. However, the bottom material can also be integrally formed with concrete for forming the medium frame. The bottom material formed of concrete is
A number of through holes are opened to allow seawater to pass through.
The holding rod 6 is formed, for example, by reinforcing a 10 mmφ
They are fixed in parallel at m intervals.

Further, the holder 7 is fixed to the medium frame 1B in order to fix the peripheral wall 2. The holder 7 has, for example, a reinforcing bar of 10 mmφ bent in a U-shape, and both ends are fixed vertically to the culture medium frame 1B. The holders 7 are independently fixed to four sides of the rectangular medium frame 1B. Holder 7 is used when molding medium frame 1B with concrete.
The end is embedded and fixed, or a through-hole is provided in the culture medium frame, and the medium is inserted into the through-hole and fixed. The holder inserted into the through hole is fixed, for example, by clamping the upper and lower surfaces of the culture medium frame with nuts screwed into the holder. The holder 7 is provided with a rod 7A at the middle and the lower part, which binds the straps to be the peripheral wall 2.

The peripheral wall 2 is a member that allows the ocean current to pass therethrough but consumes the kinetic energy of the ocean current when passing through, for example, a member that is vertically fixed to the holder 7 so as to form a gap. Palm, a natural material, not only consumes the energy of the kinetic movement of the passing ocean currents, but also has the advantage that spores and seeds of seaweed easily adhere to it and that seaweed can thrive. However, the fishing reef of the present invention does not specify the surrounding wall as a palm. Instead of the strap, it is also possible to use a number of wires made of synthetic resin bundled together and bound to a holder so as to form a gap. Further, a net material that allows an ocean current to pass can also be used. The height of the palm serving as the peripheral wall 2 is determined in consideration of the size of the culture medium frame 1B. For example, the height of the peripheral wall is 5 to 30%, preferably 10 to 20% of the outer shape of the culture medium frame.
The peripheral wall of the culture medium frame with an outer shape of 1 x 1 m has an optimal height of 1
0 to 20 cm.

The sand and mud mat 3 is manufactured by putting sand and mud in a bag having countless voids. The sand and mud mat 3 is a medium frame 1B
The size and the shape are such that they can be placed in the hollow part of the product with almost no gap. For example, the sand and mud mat 3 is 70 × 70 × 15c
The hollow portion of the culture medium frame 1B is also formed to this size. However, since the fishing reef of the present invention does not specify the size of the sand mud mat, the size of one side of the sand mud mat is, for example, 30 to 500 cm, preferably 50 to 3 cm.
00 cm, more preferably 50 to 150 cm. The thickness of the sand and mud mat is, for example, 5 to 50 cm,
Preferably it is 10 to 30 cm. If the sand and mud mat is too thin, eelgrass cannot grow efficiently. However, when the sand / mud mat is made thicker, a large amount of sand / mud needs to be introduced, which increases the production cost. The sand mud mat is used to grow eelgrass,
Considering both the manufacturing cost and the thickness, it will be optimal for the seabed to be installed. It is not always necessary to put one sand and mud mat in the hollow part of the medium frame. A plurality of sand and mud mats can be placed in the hollow portion. In this case, the size of the sand / mud mat is reduced. Moreover, the fishing reef which puts several sand mud mats in a hollow part can also put various sand mud mats. For example, a sand mud mat containing sand mud and a sand mud mat containing reed humus as a source of nutrients in addition to the sand mud can also be provided.

A bag having a myriad of voids containing sand and mud is made of, for example, a nonwoven fabric having voids between fibers by gathering fibers three-dimensionally and without directionality. As the nonwoven fabric, one in which an innumerable number of fiber intersections are bonded or non-bonded can be used. Ideally, the nonwoven fabric is made of natural fibers such as coconut fiber, wool, and hemp blended fiber. However, a nonwoven fabric made of synthetic resin fibers can also be used. As the nonwoven fabric, a material having fine gaps through which seawater can pass but sand and mud filling the inside do not leak is used. The nonwoven fabric is formed into a closed bag with sand and mud put therein and sewn or adhered.

The eelgrass reef having the above structure is manufactured as follows. The reef main body 1A and the medium frame 1B are separately formed of concrete. A sand / mud mat 3 is manufactured by filling a nonwoven bag with sand / mud. The sand / mud mat 3 is placed in the hollow portion of the culture medium frame 1B. At this time, the upper surface of the hollow portion is opened. Eelgrass seeds and germinated seedlings are fixed on the sand mud mat 3 in advance. The seeds and seedlings are established and the sand mud mat 3 can proliferate eelgrass in a short time. However, the sand and mud mat 3 does not necessarily need to plant seeds or seedlings. This is because seeds floating in seawater adhere and propagate. The top opening of the culture medium frame 1B is closed. The peripheral wall 2 is provided by binding the palms to the holder 7 of the culture medium frame 1B. The reef main body 1A is placed on the sea floor, and the medium frame 1B is placed on the reef main body 1A.

[0020]

The fishing reef of the present invention for eelgrass has a feature that eelgrass can efficiently grow on the upper surface of the fishing reef block. That is, the reef of the present invention, around the top of the reef block,
A sand-and-mud mat that allows sea currents to pass, but has a surrounding wall of a predetermined height that consumes kinetic energy when passing, and inside the surrounding wall, on the upper surface of a fishing reef block, sand and mud in a bag with countless voids It is because is arranged. The peripheral wall provided around the sand / mud mat consumes the kinetic energy of the ocean current passing through the gap. The current that flows slowly through the surrounding wall does not sweep the eelgrass vegetated on the mud mat. Furthermore, the current that flows slowly through the peripheral wall also prevents disturbance by eddies downstream of the peripheral wall. This is because the ocean current is slowly flowing over the upper surface of the sand and mud mat. For this reason, the fishing reef of the present invention effectively prevents the sea current from sweeping the eelgrass by the peripheral wall provided around the sand and mud mat.

Further, the fishing reef of the present invention has
The eelgrass grows through the bag with numerous voids because of the arrangement of the sand / mud mat containing the sand mud in bags with numerous voids. Bags with countless voids, in addition to blocking eelgrass sweeping, can also effectively block sand and mud spills.
This, in combination with exhausting the kinetic energy of the ocean current at the peripheral wall, realizes an extremely excellent feature that can reliably prevent the sweeping eelgrass sweeping.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a use state of a reef block used for an eelgrass reef according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the reef block shown in FIG.

FIG. 3 is a plan view of a culture medium frame according to an example of the present invention.

FIG. 4 is a side view of the culture medium frame shown in FIG.

[Explanation of symbols]

1 ... reef block 1A ... reef main body 1
B: Medium frame 2 ... Perimeter wall 3 ... Sand and mud mat 4 ... Window 5 ... Bottom material 6 ... Holding rod 7 ... Holder 7A ... Rod

Claims (2)

[Claims] 1. A peripheral wall (2) having a predetermined height is provided around an upper surface of a fishing reef block (1), through which an ocean current can pass, but which consumes kinetic energy when passing.
An eelgrass reef characterized by comprising a sand mud mat (3) in which sand and mud are packed in bags having a myriad of voids on the upper surface of a fishing reef block (1) inside. 2. The seagrass reef according to claim 1, wherein the fishing reef block (1) on which the sand / mud mat (3) is placed has a water passage below the sand / mud mat (3).