JPS58216631A - Artificial egg-laying bank - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an artificial spawning reef suitable for spawning fish, especially coconut squid. 4 The purpose is to maintain and increase fishery resources by creating an environment suitable for spawning and breeding of fish, especially squid.

In recent years, squid that have migrated to Japan's coastal areas and are caught have become a valuable marine food resource. It is generally known that squid eggs are laid in finger-shaped agar-encased egg sacs on substrates such as rocks, boulders, and fixed nets in coastal areas. For example, in the case of spear squid, they are laid on the ceiling of rock ledges in rocky reef areas, in cracks and crevices of rocks, on the underside of netted dohyo, or in the roots of seaweed, and the water depth is 5 to 10 meters if it is shallow. At depth, it reaches 20 to 60 meters. These natural spawning reefs are not necessarily widely distributed throughout the coastal area, and many of them are in poor environments such as unstable settlement or easy attack by foreign enemies, and the rate of coral reef formation is low. The development and placement of spawning reefs that are suitable for maintaining and increasing squid resources has an important meaning in coastal fisheries.

The present invention provides an artificial spawning reef that was found to have a large number of attached eggs and good stability of attachment after installing various spawning experimental reefs with different designs, water depths, etc. It is something to do. That is, it has been found that an artificial spawning reef having an FRP molded plate as a spawning surface has an excellent spawning effect and an effect of stabilizing egg sac adhesion.

FRP (Flber Re1nf) used in the present invention
ercedPlastics) Refers to sheet-shaped materials formed by the lay-up molding method, filament wind molding method, press molding method, or injection molding method, and is usually about 2 to 20 mm thick. Use as a sheet. If it is 2 mm or less, the strength as a sheet is sufficient, but if it is 20 mm or more, it will exceed Sakaki construction! The amount would be excessive and it would be uneconomical. The color is the natural color of the resin and glass fiber used (transparent to
Coloring is optional, ranging from translucent amber color, 9 thin edge colors, brown) to white to black using toner and pigment, but in the test,
Even with the natural color, a sufficient number of egg pastes were observed to adhere. Examples of the resin used include thermosetting resins such as epoxy resin, unsaturated polyester resin, vinyl ester resin, epoxy acrylate resin, and phenol resin.

Among these, unsaturated polyester is the most suitable in terms of processability, safety, and economy.

The fibers used in the present invention are mainly glass fibers,
Roving, yarn cloth tape, roving tape, chopped strand mat, roving cloth,
There are single uses such as yarn cloth, four uses, and multiple uses such as lamination and lamination. Although selected depending on the molding method, reinforcing fibers such as aragid fibers may be used in addition to glass fibers. In order to improve the rigidity of the resin, fillers such as calcium carbonate, clay, talc, gypsum, barium sulfate, alumina, etc. may be included in addition to the above-mentioned colorants. Thus, it is also possible to attach sand, pebbles, etc. to the molded product before the resin hardens during molding or immediately after molding, and then to fix the sand or pebbles as the resin hardens.

To construct a spawning reef that has a fish habitat space with FRP sheets placed on the ceiling as spawning boards, a three-dimensional frame with pillars or walls made of structural materials such as FRP, concrete, engineering plastic, or steel is required. Attach an FRP sheet to the body to serve as a spawning board. If necessary, a heavy substrate such as concrete may be installed in order to increase the stability during sinking, but the spawning reef of this invention uses an FRP sheet as a spawning board and a three-dimensional space that forms a space using this as a ceiling. It is sufficient to have a target frame body, and it may be of a structure in which the side or lower surface is open.

FRP or concrete is preferable in terms of integration with the FRP spawning board, formability, seawater corrosion resistance, etc. As a spawning reef, it is possible to use not only one spawning board but also a combination of multiple layers or tiers. The height should be 20 cm or more, preferably 30 cm or more
It is best to make it 100 cm.

Also, the area of the spawning board is not particularly limited, but the experimental results show that the number of eggs per area ranged from a few to several hundred, so 10Or! ~10i is desirable. These spawning boards may be composed of one or more spawning boards.Also, the space volume directly below the spawning board may be divided by a partition plate or the like. Furthermore, in many cases, it is desirable that the egg-laying plate is a flat plate, since the largest number of egg sacs are attached to the lower surface of the horizontal flat plate made of FRP. Spawning has also been observed on the almost vertical edges of semilunar (arc-shaped curved cross-section) plates, and is not necessarily limited to flat horizontal plates.

The structural materials that make up the frames that support these egg sacs must withstand long-term use underwater, have sufficient strength to withstand external forces such as wave force and tidal force, and have sufficient strength to support the ecology of the egg sacs. There are no particular restrictions on the material or structure, as long as it has a space under the spawning plate that has good drainage from the surface and is appropriately shielded. However, from the viewpoint of combination with FRP spawning boards, the above-mentioned (FRP side wall boards, columns, concrete columns, etc.) are particularly effective.

Although the spawning reef of the present invention is mainly targeted at squid, it can of course also be used as a spawning reef for other squid species that lay their egg sacs on the lower surface of the horizontal plate, such as octopuses, etc.
It can also be used as a protective reef for young fish and a catchment reef for small adult fish.

EXAMPLES Hereinafter, the present invention will be specifically explained in detail with reference to Examples.

Example 1 Glass chopped strand mat FRP# with a thickness of 4ynx molded by a hand lay-up method using a glass surface mat for the outermost layer and an unsaturated polyester resin
! A spawning reef 1 with a height (H) 1.2 m, a width (W) 1 m, and a length (L) 1 m as shown in Figure 1 as a sheet.
was produced. As shown in the figure, two spawning plates 2, 2
is arranged as a two-layer horizontal plate with a height of 50 crrL and a height of 1 d, each having an area of 1 d, its two sides 3 and 3 are FRP wall surfaces, and the other two sides 4 and 4 are open. Note that the base portion 5 was made of concrete. This is the depth of the Sea of Japan, 5
When test installation was carried out for about 2 months during winter at a distance of 0 to 60 m, the first test reef had over 200 egg sacs on the lower surface of the lower horizontal board, and the second test reef had 150 to 200 eggs as well. Sacs were observed to be born. The number of eggs contained in one egg paste was 60 to 80, accounting for 60% of the total. We also investigated the occurrence of capital offenses, but no capital offenses were found.

Embodiment 2 As shown in FIG. 2, the upper half of a horizontal cylindrical serpentine frame 6 parallel to the central axis is made of glass roving and unsaturated polyester resin and has a diagonal lattice formed by filament winding. A downward arc-shaped spawning board 7 is molded from glass chopped strand mat and unsaturated polyester resin and attached. The color after curing was amber color. When test installation was carried out in the same sea area as in Example 1, several hundred egg sacs were found attached to the inside of the FRP spawning board, and approximately 58 eggs, approximately 58 eggs, were deposited on the lower edge of the outer surface of the same board. was observed.

Example 3 As shown in FIG.
A cross-sectional enclosure plate 10 is vertically erected at the corner, and flat spawning plates 11 and 1111 made of FRP are installed in three tiers.
A partition plate 12 is attached between the corners of two sets of diagonally facing enclosure plates 10 and 10 to partition the space below the spawning board 11 at each stage, thereby forming a rectangular parallelepiped-shaped spawning reef.

Example 4 A rectangular parallelepiped frame made of a concrete frame with a square cross section of 20 cWL on each side. A flat spawning board 14 made of FRP with a thickness of 311 jI was attached to the ceiling surface of 1301.5 m square, and FRP lattice was installed on two opposing sides. 15 to construct the spawning reef shown in Figure 4. Similarly, we conducted a comparative test with an all-concrete spawning reef with a concrete ceiling and found that the spawning reef with FRP board had 80 spawning reefs after being installed for three months in the winter at a depth of 30 meters along the northern Japan Sea coast. Although a strong number of egg sacs were observed, no egg sacs were observed on the spawning reef with a concrete spawning surface.

[Brief explanation of drawings]

The drawings show a spawning reef according to an embodiment of the present invention; FIG. 1 is a perspective view of the spawning reef according to the first embodiment, and FIG. 2(a) is a perspective view of the spawning reef according to the first embodiment. (b) is a front view and a side view of the spawning reef of Example 2, respectively, and FIGS. 3 and 4 are respectively of the spawning reef of Example 3. and 4 are perspective views of spawning reefs. 1. Spawning reef, 2. Spawning board, 3. Side, 4. Side, 5. Base, 6. Gabion-shaped frame, 7. Spawning board, 8
...Egg glue, 9.. Basal part, 10.. Shroud plate, 11..
Spawning board, 12... Partition plate, 13... Rectangular parallelepiped frame, 14
... Spawn plate, 15 bones, FRP lattice.

Claims (5)

[Claims] (1) An artificial spawning reef characterized in that an FRP sheet is arranged as a spawning plate on the ceiling within a three-dimensional frame having a living space for squid and octopus fish. (2) The artificial spawning reef according to claim 1, wherein the spawning plate is a flat or semicircular FRP sheet. (3) The artificial spawning reef according to claim 1, characterized in that the space in which the spawning boards are arranged on the ceiling is provided in multiple stages. (4) The artificial spawning reef according to claim 1, characterized in that the space in which the spawning board is arranged on the ceiling has an open part on the side surface. (5) The artificial spawning reef according to claim 1, which has a space in which a spawning board is arranged on the ceiling in a cylindrical serpentine frame made of FRP.