JPH1075683A - Artificial spawning reef for arctoscopus japonicus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an artificial spawning reef for Arctoscopus japonicus installed at an arbitrary position of a coastal zone. SOLUTION: This artificial spawning reef comprises a material such as a plastic excellent in durability, corrosion resistance, flexibility and touching feeling and obtained by standing an artificial spawning base (a) formed by many wires 1 and 1' fixed at the crossing parts 2 and having prescribed shapes on a upper surface 3a of a stand 3 having an arbitrary shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial spawning reef for groupers located in a coastal area.

[0002]

2. Description of the Related Art Poplar group resources tend to be drastically reduced due to overfishing and devastation of spawning grounds, and as a countermeasure for resource recovery, it is necessary to not only control fishing but also to create a spawning ground with excellent reliability. Conventional methods for constructing an egg-laying ground for groupers mainly include natural perennial large seaweeds (hereinafter, natural perennial large seaweeds) such as Uganomok belonging to the genus Jolomoku, which belongs to the genus Jonomok, which is a spawning substrate, and the like. Research and development of spawning reefs composed of artificial spawning algae have been attempted in many ways. to date,
As an example of a demonstration test of the construction of a hatchery spawning ground in various parts of the coastal area of northern Japan, artificial spawning algae as spawning substrates that form the most basic spawning reef are considered to be natural perennial macroalgae in the early winter season. It mainly consists of plastics material such as polyethylene or polypropylene or synthetic fiber material, etc., and its shape is relatively hard plastic wire, etc. Most of synthetic fibers having relatively excellent flexibility, such as twine and rope, have one end untwisted and the other end bound and bound to form a branch shape. The above-mentioned conventional artificial spawning algae, each of which is made up of one or a plurality of single strains, is fixed to a weight such as a concrete block or sandbag to form an artificial spawning reef to form an artificial spawning reef. It will be installed on the seabed, that is, on the seabed rock mainly below the low tide line near the breaking area, and an artificial spawning fishing ground will be created. However, these artificial spawning reef facilities are often installed in the early winter season, when they are often timed, and the location of the artificial spawning reef facilities protrudes below the low tide line near the breaking wave area, that is, above the seabed at a depth of 2 to 4 m. Because of being on rocks that were damaged, they were inevitably susceptible to severe waves, and these installed artificial spawning reef facilities had the drawback that breakage or spillage would occur.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a method of laying hatha-sata in the spawning season, that is, from late November to mid-December.
Diving surveys of spawning grounds to understand the spawning ecology of groupers and the colonization of native perennial macroalgae as spawning matrices, and to provide a grouper reef composed of artificially abundant artificial seaweeds that are functionally superior What you want to do.
In the northern Japan waters, hathahata is a cold-sea bottom fish that approaches the coastal area in a thick group for spawning from late November to mid-December, and protrudes mainly on the seabed 2 to 4 meters at night. The stems of perennial macroalgae that grow naturally on the reef and the upper part of the main branches are washed away, and the sticks near the lower part of the main branch are used as a center axis or a base to produce a sticky egg mass about 4 to 5 cm in diameter. There is a habit of attaching. Depending on the type of natural perennial macroalgae, some of these spawning substrates can reach several meters in the summer, but the upper part of the stem has a prosperous leaf body. Due to a large number of air bubbles, the flowing water resistance becomes extremely large. Therefore, from late summer to autumn when the waves are intense, it is not possible to withstand the wave resistance, and the upper part of the stem will be broken and washed away, and in winter it will be reduced to about 50 cm in algal height. However, at this time, that is, at the time of hathahata spawning,
Although these remaining natural perennial macroalgae are still in an upright state, the stems are inevitably shortened to a minimum height, so that they can naturally become structures that can withstand wave resistance and It is said that it has excellent wave resistance because it is rich in strong and moderate flexibility peculiar to perennial seaweed. The egg mass of the grouper, which was born on the natural perennial macroalgae that is the target of these spawning substrates, begins to hatch from the fish eggs on its surface, and it takes 50 days to complete hatching of all surviving egg masses.
It takes about 60 days. During that time, there are many seasonings due to stormy weather even in the season, so some of the egg masses that have settled on the seaweed as the above egg-laying substrate may not be able to withstand the violent rocking caused by waves and fall or The main branch may be broken and run off, and may be launched on the coast. Furthermore, the water depth at which these natural perennial macroalgae grow naturally,
Because it is in the same symbiotic water zone as useful large seaweeds such as natural kelp, natural perennial large seaweeds are not only collected at the same time as kelp, but also natural kelp, etc. Reproductive obstacles were often the subject of aggressive eradication. In addition, as described above, a conventional hathahata artificial spawning reef composed of artificial spawning algae formed of plastics and synthetic fiber materials, etc., certainly has the appearance of a naturally occurring natural perennial large seaweed alone. Although it is configured to be an aggregate of artificial spawning algae manufactured by imitation, that is, a colony, there is a limit in terms of technical and cost imitation, and the seaweeds that constitute the aggregate are each Since it is an independent unit, it is not only structurally and physically instable, but also heterogeneous in material and feel to external loads, especially dynamic loads caused by waves. There was nothing. Therefore, the effect is merely as small as small fish living in shallow waters.

[0004]

As a means to solve the problems of the conventional artificial spawning reef as described above, a diving survey was conducted in the early winter when hathahata approached the coastal zone for spawning, We investigated the state of natural perennial macroalgae as a spawning substrate remaining on the seabed below the low tide line and the state of egg masses of settled groupers. As a result, the egg mass of the grouper is sticky, so that the stem of the spawning substrate and the branch of the main branch are securely formed as a center shaft or a stand, and the egg mass in a ball-like state is hardened and a stable state is secured. Could be confirmed visually. As a spawning substrate, natural perennial macroalgae first grows approximately 10 cm to 15 cm from the root at a height of 10 cm to 15 cm from the root when a large static load, that is, flowing resistance, is applied from almost the horizontal direction. Under a condition where a large dynamic load from the same direction, that is, a wave resistance is applied subsequently, the stalk is gently moved in a range where the front, rear, left and right is substantially horizontal from the above position. It was determined that the rocking motion did not occur, but that the rock itself violently rocked or that the main branch did not hit the seabed. From the above, simply imitating the shape of natural perennial large seaweed as a single artificial spawning algae by simply using conventional plastics and materials such as synthetic fibers is extremely technically and costly. It turned out to be difficult. Therefore, in the present invention, durability, corrosion resistance,
The wire as an egg-laying substrate, which is made of a material having excellent flexibility and feel and is formed in a predetermined shape, for example, several large and small arches, each having a large number of fixed mating portions, has a lower end formed of a concrete block. It is constructed on a pedestal upper surface of an arbitrary shape made of a material having a high specific gravity to constitute an artificial spawning reef of a hathahata.

[0005]

The spawning substrate of the present invention has a structure in which the mating portions are fixed, and is firmly pierced and planted on the upper surface of the pedestal, and has a very small resistance to external loads caused by flowing water and waves. Since it is formed, it is possible to hold the predetermined shape stably and rationally.
It also has the advantage that it can be provided easily and at low cost. Incidentally, the overall structure of the spawning reef of the present invention is a simple and low resistance spawning substrate is appropriately planted on the upper surface of a pedestal having a large specific gravity such as a concrete block, so the center of gravity of the reef is near the pedestal. Since the vehicle is at the lower position, that is, at a lower position, the possibility of an accident caused by a fall, a slip, or the like can be minimized. Further, as a predetermined shape, that is, as one of the embodiments, several large and small arch-shaped wire rods as an egg-laying substrate are made of a material having excellent durability, corrosion resistance, flexibility and feel. Since the egg masses of the laid eggs are centered on the wire rod and the mating portion is used as a base, the slaughter accident caused by falling off of the egg mass occurs It is difficult to do.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the illustrated embodiment. The artificial spawning reef A of the grouper according to the present invention comprises a large number of spawning substrates a planted on the upper surface 3a of the pedestal 3, as shown in FIG.
As shown in FIGS. 2 and 3, the spawning substrate a has a predetermined shape in the form of an arch and is made of a plastics material or a metal core material or a pipe material excellent in durability, flexibility and touch, and the plastics material or the like. The wire rods 1 and 1 'formed by coating the synthetic fiber material are brought into contact with each other at predetermined positions, and then the connecting parts 2 and 2' are fixed by a method such as fastening or welding. It is desirable that the outer surface of the spawning substrate a be colored as dark brown as the naturally occurring perennial macroalgae. In particular, since the surfaces of the wires 1 and 1 'are formed of plastics or synthetic fibers made of polyamide or polyvinyl alcohol having excellent hydrophilicity, the affinity for seawater, that is, the ease of adaptation to seawater is improved.
Further improvement in the egg-laying effect can be expected. The pedestal 3 is mainly made of concrete and is manufactured in an arbitrary shape, but has a lifting inverted U-shaped ring 4 at a predetermined position on the upper surface 3a. Therefore, after the spawning season, the spawning reef A of the present invention can be pulled up at any time, which has an advantage that the management work is easy. In addition, the pedestal 3 has a plurality of legs (not shown) around the periphery for the purpose of maintaining stability, since the seabed of the reef to be installed is often uneven.
Is also an effective method. The spawning substrate a formed in the shape shown in FIG. 2 and FIG.
During the early stage of curing, the terminal 1a is pierced and planted on the upper surface 3a of the pedestal 3, respectively. As a planting method after curing, a spawning substrate a is previously plated (not shown). It is also possible to fix the entire plate on the upper surface 3a of the pedestal 3 with bolts and nuts.
Since the artificial spawning reef A of the grouper according to the present invention has a structure as shown in FIG. 1, it has a so-called broom-like shape in which one end of many conventional relatively hard plastic wires is bundled and bound with a string or the like. Egg-laying substrate and synthetic fiber such as twine and rope, which have excellent flexibility, are compared with egg-laying substrate in which one end is untwisted to form a strand and the bundled other end and untwisted base are similarly bound. Since the porosity of the spawning substrate a is large and the mating portions 2 and 2a are fixed and reinforced,
The artificial spawning reef facility is extremely stable because it has extremely low resistance to flowing water and waves in any direction and its center of gravity is located near the pedestal 3. In addition, as another embodiment of the present invention, as shown in FIG. It is also possible and easy to install the device at a predetermined water depth in a detached state through the mooring cable 7 having a length or height, and therefore, it is possible to install the device even if the installation sea area is deep. It will also have possible properties. Further, for example, even if the seabed in the installation sea area, which is considered to be unsuitable as a conventional hatchery spawning ground, is the sandy seabed 8, only the weight 6 is buried in the sandy seabed 8 to improve the fixing force. The pedestal 3 having the floating body 5 and the spawning substrate a planted on the upper surface 3a, that is, the artificial spawning reef A
Can be ensured at a substantially predetermined water depth in a detached state.

[0007]

The artificial spawning reef of the grouper according to the present invention has extremely low resistance to external loads due to its structure.
Since it is possible to maintain the stability rationally, it is possible to minimize the occurrence of accidents due to breakage, overturning, sliding, and the like. Further, the spawning substrate constituting the present invention which stably retains a predetermined shape can promote the spawning activity of the grouper, i.e., the contact activity, etc. The effect of preventing dropping of the epiphytic egg mass generated by the swinging of the egg-laying substrate and the tapping, etc., can be expected to improve the efficiency of natural hatching.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an artificial spawning reef of the present invention.

FIG. 2 is a partially cutaway enlarged front view of the artificial spawning reef of the present invention.

FIG. 3 is a partially cutaway enlarged front view showing another embodiment of the present invention.

FIG. 4 is an installation state diagram showing another embodiment of the artificial spawning reef of the present invention.

[Explanation of symbols]

 1.1 '. Wire 1a. End of wire 2.2 '. 2. Intersection of wire rod Pedestal 3a. Top of base 4. Reverse U-shaped ring 5. Floating body 6. Weight 7. Mooring line 8. Sandy seabed A. The artificial spawning reef of the present invention a. Spawning substrate of the present invention

Claims (1)

[Claims] 1. An artificial spawning substrate made of a material having excellent durability, corrosion resistance, flexibility, and feel and formed of a large number of wires of a predetermined shape, each having an interlocking portion fixed thereto, is implanted on the upper surface of a base of any shape. An artificial spawning reef for hatahata, which has been established.