JP3948769B2 - Fish reef - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fish reef, and particularly to a fish reef that is effective when used for a squid spawning reef, and that can prevent oysters and squirts from adhering to the substrate of the fish reef.
[0002]
[Prior art]
The conventional technology generally uses a habit of squid laying eggs on the bottom of a ledge in a natural sea area, and constitutes a fish reef as an artificial ledge. This prior art is a fish reef composed of a substrate for spawning squid having a horizontal spread on the lower surface and a leg or a frame provided under the substrate. In addition, fish reefs are known in which not only one egg-laying substrate but also a plurality of eggs are stacked with a predetermined interval.
[0003]
[Problems to be solved by the invention]
However, the above-described conventional fish reef is generally used in the form of a flat plate as a substrate used for this, but if the fish reef constructed in this way is installed in the sea for many years, In particular, sea squirts adhere to the lower surface of the substrate, and in particular, there is a problem that it is impossible to lay eggs. In addition, natural rock shelves have an uneven surface, which improves the spawning environment for squids, whereas conventional flat fish reefs are inferior to natural rock shelves in this respect. It was.
[0004]
The present invention is a completely new technology developed in view of the above-mentioned conventional problems, and it is possible to construct a substrate of an artificial reef into a complicated shape adapted to the spawning habit of squids, for example. This technology is provided.
[0005]
Furthermore, in the present invention, by constructing a fish reef substrate in a specific structure, deposits such as sea squirts are prevented from adhering to the substrate. It provides an entirely new structure of reef technology that has been successfully implemented over the years.
[0006]
[Means for Solving the Problems]
The fish reef according to the present invention is a completely new technology that has fundamentally improved the above-mentioned conventional problems, and the gist of the first invention is that a substrate having a planar spread is provided on a frame constituting the fish reef. In the fishing reef as described above, the bottom surface of the substrate is provided with a slope recessed on the upper surface side, and a fine hole is provided on or near the top of the slope recessed on the upper surface side.
[0007]
The gist of the second invention of the fish reef according to the present invention is the fish reef according to the first invention, characterized in that the fine holes have an inner diameter of 1 to 50 mm and one or more fine holes are provided in the substrate. The gist of the third invention is the fish reef according to the first invention or the second invention, wherein the micropore has a hole cross-sectional area of 0.002 to 5% relative to the substrate area .
[0008]
As a result of researches on the ecology of squids, squirts, oysters and other fish over the years, the present inventors have found that these squids, squirts, oysters are all under the rock shelf. Although there is a habit of laying eggs, it was discovered that the conditions of egg laying and the growth of these larvae differed in relation to light.
[0009]
That is, for example, ascidian eggs become larvae after fertilization, start to swim and swim, and then gradually grow by adhering to rocks and the like with attachment protrusions at the tip of the larvae. At this time, it is clear that the juveniles can recognize the direction of light, react sensitively to the decrease in brightness, adhere to dark areas, but not to bright areas. became. This is why squirts are often found in rocks.
[0010]
On the other hand, it was clarified that adult squids do not react by recognizing the direction of light so sensitively and lay eggs in a relatively light place on a small rock shelf. Therefore, it is important for the selection of the substrate for spawning squid to have a lower surface that enables spawning of the squid rather than to light, and furthermore, the inclined surface such as irregularities on the lower surface of the spawning substrate. It has also been found to be more preferable.
[0011]
Based on these discoveries, the present inventor, as in the first invention of the above-described fish reef, has a structure in which a fine hole is provided in the egg-laying substrate of the spawning reef, and the light is emitted from the fine hole on the bottom surface of the egg-laying substrate. When diffused, the squids lay eggs on the lower surface of the egg-laying substrate through which light enters, but no sea squirts or the like were attached or spawned. Therefore, it was confirmed that by creating such conditions artificially, it is possible to maintain an environment in which squid lays eggs well for many years.
[0012]
Furthermore, in order to allow light to enter the lower surface of the egg-laying substrate of the spawning fish reef, it is conceivable that a hole or slit having a large inner diameter is drilled, or that the egg-laying substrate is composed of a lattice-like wire mesh, As a result of repeated experiments by the present inventors, it has been found that the amount of light incident on the lower surface of the egg-laying substrate is effective even if the amount is small.
[0013]
Therefore, as described above, when a large hole or slit is formed in the egg-laying substrate, or when the egg-laying substrate is constituted by a lattice-like wire mesh, the processing is complicated, and there is a problem with the strength of the egg-laying substrate. However, as in the first invention of the above-described fish reef, when a micropore is provided in the egg-laying substrate, the processing is extremely simple and the strength of the egg-laying substrate can be sufficiently maintained. Furthermore, even in squids, it is more effective for egg laying and larval growth if the amount of light is small.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The fish reef and its substrate when the present invention is used for the squid spawning reef will be described with reference to FIG. 1. FIG. 1 is a perspective explanatory view of the squid spawning reef according to the present invention, and FIG. 2 is the spawning of the squid spawn in FIG. 3 is a bottom explanatory view of the egg-laying substrate attached to the fish reef, FIG. 3 is a cross-sectional enlarged view of the main part of the egg-laying substrate of FIG. 2, and FIG. 4 is a perspective view of another example of the fish reef.
[0015]
In FIG. 1 to FIG. 3, reference numeral 1 denotes a squid spawning fish reef according to the present invention, comprising a concrete frame body 2 and a spread egg-laying substrate 3 attached to the upper part of the frame body 2. It is configured. The egg-laying substrate 3 is attached and fixed to the upper part of the frame 2 via bolts (not shown).
[0016]
The egg-laying substrate 3 is made of synthetic resin (FRP) reinforced with glass fiber or high elastic modulus fiber. On the lower surface of the egg-laying substrate 3, three left and right, a total of nine convex portions 4 inclined in a quadrangular pyramid shape are provided so as to protrude, and a fine hole 5 is provided at the top of each convex portion. Is formed as a through hole.
[0017]
The thickness of the egg-laying substrate 3 is about 4 to 10 mm, the overall width is about 900 to 1500 mm, and the width of the space of each room formed by the protrusions 4 is about 300 to 500 mm. Moreover, the internal diameter of the micropore 5 drilled in the top part of the convex part 4 is about 1-100 mm. Further, the depth of each room formed by the convex portion 4 is about 100 to 500 mm, and the inclination angle of the convex portion 4 is about 10 to 50 °. The number of the fine holes 5 provided in the top part of each convex part 4 or the top part vicinity is about 1-5, and the hole cross-sectional area with respect to the substrate 3 for egg-laying is 0.002-5%.
[0018]
The frame body 2 can be made of not only concrete but also steel materials and steel plates lined with resin on the surface. The egg-laying substrate 3 can be easily attached and fixed to the front frame 2 via bolts or the like. It is also possible to embed the egg-laying substrate 3 integrally in the frame 2. Furthermore, it is also possible to constitute a fish reef 1 in which a plurality of egg-laying substrates 3 are attached in a step shape while maintaining a predetermined distance from each other in one frame body 2.
[0019]
In the above embodiment, the spawning substrate 3 is provided with the four-pyramidal convex portion 4, but the convex portion 4 having other pyramids, cones, domes, heads, waves, saw teeth and the like may be used. . Further, the number of rooms formed by the convex portions 4 provided on the egg-laying substrate 3 can be freely changed. However, it is preferable that the inner diameter of the room is about 300 to 500 mm in order to make it easier for squids to enter the room formed by the protrusions 4 to lay eggs.
[0020]
As described above, when the micropore 5 is provided at the top of the convex portion 4 of the egg-laying substrate 3, even if the diameter of the microhole 5 is small, the egg-laying substrate 3 has a smaller diameter. The light that has entered the back surface diffuses in each room formed on the bottom surface of the egg-laying substrate 3 and can irradiate the wall surface of each room. Accordingly, when the fine hole 5 is provided at the top of the convex portion 4, only one is necessary. When the fine hole 5 is provided near the top or when the egg-laying substrate 3 is flat, The number of the fine holes 5 can be increased according to the amount of light entering the lower surface. A preferable size of the hole diameter is 5 to 20 mm.
[0021]
In the above embodiment, the structure of the fish reef in which a single spawning substrate 3 is attached to the frame 2 has been described. However, as shown in FIG. 4, a plurality of spawning substrates 3 arranged in parallel vertically. 7 is also effective. The fish reef 7 is obtained by attaching a plurality of egg-laying substrates 3 to the upper portions of the large, medium and small frames 2a, 2b and 2c, and laminating the frames 2a, 2b and 2c in order and fixing them together. .
[0022]
Each of these frames 2a, 2b, and 2c is configured with legs extending downward at the four corners, so that they are stable both when they are stacked in order and when they are installed on the seabed. It can be made. Furthermore, by providing legs that extend downward at the four corners of each frame 2a, 2b, 2c, it is easy for squids and other fish to swim in the gaps between each frame 2a, 2b, 2c, and an appropriate amount of light. Can enter. In addition, the ocean currents easily flow into the gaps between the frames 2a, 2b, and 2c, and sediment and the like can be prevented from accumulating in the lower part of the fish reef 7.
[0023]
The substrate and the frame may be separate or integrated. For example, when both are made of concrete, it is more efficient to manufacture them integrally. It is also effective to leave the substrate alone on the rocks. You can also hang the substrate from rocks or floating objects. Furthermore, you may use together with a net | network.
[0024]
[Embodiment 1] Like the squid spawning fish reef as shown in FIGS. 1 to 3, it has nine quadrangular pyramid-shaped convex portions 4 and one inner diameter of 10 mm only at the top of each convex portion 4. The fish reef 1 was manufactured by attaching the egg-laying substrate 3 provided with the fine holes 5 to the frame 2. The fish reef 1 was installed at a depth of 20 m, and after one year had passed, it was lifted and observed. As a result, spawning of squid was able to be observed in large quantities, but spawning and adhesion of other squirts and oysters were not observed.
[0025]
【The invention's effect】
Since the fish reef when the present invention is used for squid spawning reef has the structure and action as described above, it has the following great effects.
[0026]
(1) In the present invention, as described above, since a micropore is provided at a predetermined position of the egg-laying substrate having a planar spread of the squid spawning reef, a predetermined amount of light is applied to the lower surface of the egg-laying substrate. This makes it possible to prevent squirts other than squid from spawning or adhering to the lower surface of the egg-laying substrate. (2) When the inclined surface is provided on the lower surface of the egg-laying substrate, the egg-laying of squid can be promoted more effectively.
[0027]
(3) When the inclined surface is formed on the lower surface of the egg-laying substrate, a fine hole can be provided at or near the apex of the inclined surface, thereby efficiently diffusing light on the lower surface of the egg-laying substrate. Can be incorporated. (4) The process of providing one or more micropores having a predetermined inner diameter on the egg-laying substrate is extremely easy and does not impair the strength of the egg-laying substrate and ensures a certain amount of light on the lower surface of the egg-laying substrate. Can be incorporated into.
[0028]
(5) The shape of the hole provided in the egg-laying substrate can be freely changed as necessary, and the ratio of the hole cross-sectional area to the substrate area is made constant, so that the amount of incident light is constant and the egg-laying substrate. The strength of can be maintained. (6) The convex part provided on the egg-laying substrate can be selected from various shapes, and by making the area and depth of the room formed by the convex part constant, the egg-laying environment of squids is remarkably improved. I can do it.
[Brief description of the drawings]
FIG. 1 is a perspective explanatory view of a squid spawning fish reef.
FIG. 2 is an explanatory bottom view of a spawning substrate attached to the squid spawning reef of FIG. 1;
3 is an enlarged explanatory view of a main part of the spawning fish reef of FIG. 2 and its substrate.
FIG. 4 is a perspective explanatory view of another first example fish reef.
[Explanation of symbols]
1 Squid spawning fish reef 2 Frame
2a, 2b, 2c Frame 3 Egg-laying substrate 4 Convex 5 Micropore 7 Fish reef

Claims (3)

  In a fishing reef in which a substrate having a planar spread is provided on a frame constituting a fish reef, a slope that is recessed on the upper surface side is provided on the lower surface side of the substrate, and the top of the slope that is recessed on the upper surface side or near the top is fine. A fish reef characterized by a hole.   The fish reef according to claim 1, wherein the micropore has an inner diameter of 1 to 50 mm, and one or a plurality of the micropores are provided in a substrate. The fish reef according to claim 1 or 2, wherein the micropore has a hole cross-sectional area of 0.002 to 5% relative to a substrate area .

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