JPH07236384A - Seaweed rock block - Google Patents

Abstract

PURPOSE:To provide a seaweed rock block effective for protecting grown body or larva of seaweed from the biting damage by seaweed-eating fish and invertebrate animal and enabling the expansion of a seaweed bed. CONSTITUTION:A block main body 12 having a prescribed shape is formed by using concrete as a material. At least the top face of the block main body 12 is made to have an irregular form to provide an adhesion substrate part 16 for seaweed. A number of rods 18 having an elastic modulus to effect the bending of the rod by the tidal current are regularly arranged on the top face of the block main body at regular spacings. The eating motion of a seaweed eating fish is inhibited by the rods and the fish is repelled by the vibration noise and the collision noise of the rods caused by the bending of the rods by the tidal current, etc. The irregular face protects the larva of the seaweed from being eaten by a seaweed-eating invertebrate such as conch shell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reef block, and more specifically, it protects adult and juvenile seaweeds from the damage of algae such as seafood and invertebrates. It relates to a reef block that can be expanded.

[0002]

2. Description of the Related Art Generally, seafood communities (seagrass beds) in shallow water are suitable for fish, shellfish (sea root resources) distributed mainly in rocks, as feeding grounds, habitats, and hiding areas. Has become. The importance of such seaweed beds has heretofore been known, and the seaweed beds are being constructed by stones and concrete blocks (so-called alga reef blocks) along the coasts of various parts of the country.

[0003] In particular, the formation of an undersea forest of kelp that directly feeds human beings, a group of Honda strawberries that provide a feeding ground for seaweeds such as abalone, turban shell, sea urchin, and seaweed, which are highly valuable as bait, and useful fish (Garamo). A large number of large-scale brown seaweed algae beds are being constructed.

On the other hand, even in excellent natural seaweed beds, some sea-state changes such as rising seawater temperature, pesticides, changes in water quality, and decrease in transparency affect each other to cause an isothermal phenomenon. I have something to do. It is difficult to recover to the current situation when such an iso-burning phenomenon occurs, especially when the ecological balance is disturbed due to the large number of algae-eating seafood, etc. However, in the northern waters, sea urchin feeding damage hinders recovery of sea shore burning, and in the southern waters, fish and Aplysia larvae themselves cause the decline of seagrass beds.

As a means for creating a seaweed bed to correct such an imbalance in the ecosystem, for example, an entire algae epiphytic substrate such as a stone or a concrete block is surrounded by a net that extends from the bottom of the water to the surface of the water. It has been proposed to prevent feeding damage to other species, or to install a cage made of wire mesh on a stable block and transplant mature seaweed into this cage to use it as a source of spores. There is.

However, the method of surrounding the whole epiphytic substrate with a net is not only economically and wave resistant but also has a problem in maintenance. In addition, a method using a wire net cage adheres to the cage. It has been pointed out that various problems to be solved have been pointed out, such as troublesome maintenance because the meshes are clogged and the mother algae die out due to lack of sunlight unless adhered organisms are always removed.

[0007]

Therefore, according to the present invention, at least the top surface portion of a block body having a predetermined shape made of concrete is formed to have an uneven surface, and an epiphytic substrate portion for seaweed is provided to the epiphytic substrate portion. By using an algal reef block composed by arranging a number of rod-shaped bodies that are set to have an elastic modulus that can be flexed due to tidal current, etc. at a predetermined interval and in line, seaweed can be protected from feeding damage such as algae eating seafood It aims to protect adult and juvenile species.

In this case, the height of the rod-shaped body is two or more, that is, the height is approximately the same as the growth point of the adult seaweed grown on the epiphytic substrate of the block body and the height is lower than that. Preferably, the pressure receiving plate for the flow is arranged along the height direction of the rod-shaped body so that these rod-shaped bodies are bent at random, and further, the block body is It is preferable to form the planar shape into a substantially cruciform shape for hydraulic stability.

[0009]

[Operation] In this alga reef block, not only the rod-shaped body interferes when the algae eat the seaweed, but also the vibrating sound caused by the Karman vortex caused by the tidal current and the adjacent rod-shaped body come into contact. It is possible to repel the alga-eating fish by the impact sound of the time, and the unevenness of the epiphytic substrate part interferes with the feeding of juveniles by snails and sea urchins to improve the survival rate and expand the seaweed bed. It is possible.

[0010]

The preferred embodiments of the algal block according to the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2, the algal reef block 10 according to the present invention is formed by a block main body 12 which is made of concrete and has a planar shape that is excellent in hydraulic stability, preferably a substantially cross shape. Has been done.

The top surface portion 13 of the block body 12 is also
On the inclined surface 14, an epiphytic substrate portion 16 for processing the seaweed A is formed on the inclined surface 14 and the irregular shape of the epiphytic substrate portion 16 is fed by algae snails, sea urchins and the like. Set the shape so that it will not enter as much as possible.
Specifically, when the block main body 12 is molded, crushed stone of 40 mm or more is used as coarse aggregate, and the surface is washed out to give a desired uneven shape (see FIG. 3). In addition, it is preferable to give a large roughness to the surface by using a rake or the like before the poured concrete is cured at the top portion without the formwork.

On the other hand, as shown in FIG. 3, a large number of rod-shaped bodies 18 made of, for example, FRP resin are arranged in the epidemic substrate portion 16 at predetermined intervals and in line. These rod-like bodies 18 are set to such an elastic modulus that they are bent by a tidal current, and the height dimension thereof is set to the growth substrate portion 1 as described later.
It is preferable to set two kinds of height dimension H substantially the same as the growth point of the adult of the seaweed A grown on No. 6 and height dimension h lower than that.

The rod-shaped members 18 themselves are firmly held upright by anchor means 20 made of an FRP resin plate embedded at a predetermined depth position of the epithelial substrate portion 16 and at the same time as the surface of the substrate portion 16. A water resistant protective tape 22 is wound around the boundary portion. Further, pressure-receiving plates 24 are attached to each rod-shaped body 18 in a random direction along the height direction thereof, and the rod-shaped bodies 18 are bent in various directions when a wave or a flow acts on the pressure-receiving plate 24. To do.

When using the alga reef block 10 according to the present invention having the above-described structure, after the adult seaweed A is attached to the epiphytic substrate 16 by using an underwater bond or the like, it is then washed with rubble stones or the like in a shallow sea area. To form a seaweed bed development facility. Then, as time passes, the algae-eating fish living in this sea area try to eat the leaves of the seaweed A attached to the epiphytic substrate part 16 of the block body 12, but the rod-shaped body 18
Not only is set to have substantially the same height H as this leaf body, but also the interval at which the rod-shaped bodies 18 are erected stands in the way of feeding, so that unnecessary feeding damage can be prevented (FIG. 4). reference). In this case, the height H of the rod-shaped bodies 18 is set according to the height of the growth point of the seaweed, and the standing interval is set to an interval of about the body length of the alga-eating fish, which is assumed, but the standing density is set. If it is set too high, the leaf-like organisms collect and bring about the effect of collecting fish that feed on these leaf-like organisms, so it is preferable to set the intervals to at least several cm.

When each rod-shaped body 18 bends due to a tidal current or the like, not only does it intermittently come into contact with an adjacent lower rod-shaped body 18 to generate a collision sound, but also each rod-shaped body 18 itself or the pressure receiving plate 2
Various Karman vortices are formed behind it due to the tidal current acting on No. 4 and vibration noise is generated, which threatens algae-eating fish with a collision noise and interferes with feeding (see FIG. 5). These rod-shaped bodies 18 are not only bent in random directions by the action of the pressure receiving plate 24 arranged in the lengthwise direction but also generate vibration sounds of different frequencies. It can interfere with infant feeding.

On the other hand, even if algae, such as snails and sea urchins, feed the juveniles on the surface of the epiphytic substrate 16, the surface of the juveniles is uneven due to crushed stones and has a complicated shape. It is possible to promote the growth of seaweed A by the produced and survived juveniles, and as a result, it is possible to expand the seaweed bed.

[0017]

As described above, according to the alga reef block of the present invention, when the alga-eating seafood eats seaweed, not only the rod-shaped body becomes an obstacle but also it is bent by the tidal current. Repulsive repulsion of algae-eating seafood due to vibration noise or collision noise when contacting with an adjacent rod-shaped body, and further disturbing feeding of algae-eating seafood due to Karman vortex or bending in random directions. Since the unevenness of the epiphytic substrate part interferes with juvenile feeding by shellfish and invertebrates and improves the survival rate,
It has an advantage that it can prevent feeding damage as much as possible and can expand the seaweed bed.

The preferred embodiment of the alga reef block according to the present invention has been described above. However, the present invention is not limited to this embodiment, and the intervals between the rod-shaped bodies, the height dimension, etc. are assumed. It can be set appropriately according to the seafood to be eaten,
It goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is an explanatory plan view showing a preferred embodiment of the algal block according to the present invention.

FIG. 2 is a side view of the construction block shown in FIG.

FIG. 3 is an enlarged cross-sectional explanatory view of a main part of FIG.

FIG. 4 is an explanatory diagram in which the rod-shaped body of the shore block shown in FIG. 1 interferes with the feeding of algae-eating fish.

FIG. 5 is an explanatory diagram of a Karman vortex generated in the settlement part by the rod-shaped body of the surf-building block shown in FIG.

[Explanation of symbols]

10 algal block, 12 block body, 1
3 top surface part, 14 inclined surface, 16 epiphytic matrix part, 18 rod-shaped body, 20 anchor means, 2
2 protective tape, 24 pressure plate,

Claims (4)

[Claims] 1. A block main body having a predetermined shape is formed from concrete as a material, and at least a top surface portion of the block main body is formed into an uneven shape to provide a seaweed epiphytic substrate portion, and the tidal current flows to the epiphytic substrate portion. An alga reef block, characterized in that a large number of rod-shaped bodies that are set to have an elastic modulus that allows them to bend due to such factors are arranged at predetermined intervals and aligned. 2. The height dimension of the rod-shaped body is set to two types, that is, the height dimension that is substantially the same as the growth point of the adult seaweed grown on the epiphytic substrate part of the block body and the height dimension that is lower than that. The algal block according to claim 1, which comprises setting. 3. The alga reef block according to claim 1, wherein the pressure receiving plate is arranged along the height direction of the rod-shaped body. 4. The alga reef block according to any one of claims 1 to 3, wherein the block main body is formed in a substantially cross shape in a plan view.