JP2763356B2 - Artificial reefs for infants - Google Patents

Description

The present invention relates to an artificial reef for protecting and raising juveniles of freshwater fish such as crucian carp and moroko.

(Prior art)

Crucifers and moromis are reeds that grow on the shores of lakes and marshes.
It hatches in the gaps of algae, etc., and the surrounding area is a habitat until it reaches the living body. This is because they can protect themselves from many external enemies, and there are many algae, plankton, and the like serving as food nearby. However, in recent years, the area where freshwater reeds grow on the banks of freshwater lakes and marshes has decreased, and the habitats of these kindergarten lakes are disappearing. In addition, the number of large fish, such as black bass, which are foreign enemies, is increasing, and it is surprisingly unlikely that infants will become worn and reach adulthood until they become fully self-sustaining and have the ability to protect themselves from external enemies. In order to proliferate these useful fish resources, it is necessary to provide a reef that secures a habitat for hatched larvae.

Conventional reefs that protect infants and proliferate resources have a lattice-shaped frame or a cylindrical gabion, etc., and have a structure that is hidden only by hidden enemies.
However, external enemies are not limited to those of a fixed body shape, and are mixed from large to relatively small ones. Such a conventional reef having a fixed lattice size can easily enter the protected reef with an enemy less than the lattice size, and cannot function as a protective reef. In addition, hatched larvae often live in the natural environment and adhere to the leaves of delicate plants near the lake bottom to obtain food, and conventional protective reefs have functions for such larvae. Did not.

[Problems to be solved by the invention]

The present invention has been conceived to solve the above-mentioned conventional problems, and has a function of protecting a baby from an enemy of any size, and is suitable as an attachment habitat for a baby immediately after hatching. The aim is to propose an artificial reef for infants that can create a safe environment.

[Means for solving the problem]

This artificial reef for infants is an underwater reef that is installed underwater and protects the infants of freshwater fish. The two frame surfaces meet at an acute angle on the upper surface, and the space at the lower end is wide. It has a continuously narrowed valley-shaped corner, the upper surface of the frame has a rough surface, and the upper surface of the frame has a large number of continuous fine gaps.

Figs. 1 and 2 show the artificial reef of the embodiment submerged at the bottom of a lake. The cross-sectional angle θ has an acute valley-shaped corner portion 2. The frame 1 has a lattice shape, and a large number of 1 cm-wide artificial clay bristle plates 3 made of a band-like synthetic resin are fixed on the upper surface side by side in parallel at a 1 cm interval to make the upper surface of the frame 1 rough. A gap 4 is formed between the bristles 3,3. In addition, the artificial clay board 3 has a relatively coarse tissue, and has fine small gaps through which water and sediment floating in the water can pass, so that sediment and the like are prevented from being deposited on the surface thereof. . Note that a fixed bar 5 is attached between the ridges at the lower end of the frame 1 to maintain the angle θ of the corner angle.

There are many types of infant enemies, ranging in length from 20-30 cm to 1-2 cm. Infants with a body length of 1 to 2 mm are often attacked by external enemies of 20 to 30 cm. In order to adapt to all these external enemies, it is required as a function that the space width of the corner 2 is continuously narrowed from a wide place.

This artificial reef has a sharp angled corner as a space for a child to escape when encountering an external enemy, and the child can adapt to the shape of the external enemy and escape to a narrow place that is not captured. The angle θ of the corner is 90 ° or less, preferably 70 ° or less, more preferably 50 ° or less. If it is less than 20 mm, the occupation area per unit material of the reef will decrease,
Economically disadvantageous. On the other hand, if the angle is 90 ° or more, the probability of being protected from the relationship between the external enemy's physique and the child's physique decreases. Most preferably, it is around 40 °.

The upper surface of the frame that constitutes this artificial reef must be rough and must be cheap, with food attached. Flocked boards, artificial grass and the like are suitable, but not limited thereto.

The continuous gap on the top of the frame has good water flow,
It must be capable of transmitting sediment and dust floating on the water column and preventing accumulation on the upper surface of the frame. The width of the gap is 20 mm to 1 mm, preferably 15 to 5 mm, and it works effectively when provided below the corner. As in the embodiment, the band-shaped flocking boards are fixed in parallel while keeping an interval therebetween, and a gap is provided between the flocking boards, and a fine small gap is also provided on the implanting board. Can be reliably prevented,
In addition, it promotes the establishment and growth of living organisms serving as food, and can satisfy more favorable conditions as a habitat for infants.

The shape of the reef is not limited to the above. As shown in FIG. 3, the frame body 1 forming a vertical plane and the frame body 1 forming an inclined surface may be formed in a sawtooth shape having a corner 2 having an acute angle θ. As shown in FIG. 4, a frame 1 'having a semi-circular cross-section is brought into contact with and combined with the frame 1' to form a continuous arc having a corner 2 at which the angle θ at which the arc surfaces come into contact is an acute angle. Good. In this case, the angle θ is an angle at which two opposed tangents intersect, and the range of 0 <θ <90 ° is the corner 2 in the present invention. Further, as shown in FIG. 5, a mountain shape having a flat plate portion 6 on the upper surface can be employed.

This reef is usually less than 100 cm in height, preferably 70-50 cm. If it is less than 20 cm, the area becomes too small, which is not preferable.

The frame that constitutes this artificial reef is a lattice frame,
It has a water permeability, such as a rectangular frame and a ladder frame. Any material can be used as long as it can be made of metal, fiber reinforced synthetic resin (FRP), wood, or the like, can withstand the forces of water currents, waves, and the like, and can maintain its structure.

Normally, this artificial reef is submerged under the water,
When the water bottom is soft ground such as a sand mud layer, it is fixed and installed using support legs or the like to prevent settlement.

〔Example〕

70cm height, corner angle θ = 40 °, FRP shown in Fig. 1
An artificial protective reef made of a steel was placed in a large water tank, and several hundred moroko fry about one week after hatching were released, and then several black baths 2-3 cm long were released into the same water tank.

It was observed visually that the fry of this morsel flocked in the corner of the reef and could escape from black bass predation.

〔The invention's effect〕

This artificial reef has a valley-shaped corner that narrows continuously from a wide space on the upper surface, and the corner serves as a escape for the child. At the same time, the living organisms serving as food can colonize and grow on the rough upper surface with gaps, and can be formed in an environment suitable for breeding infants.

In addition, since the gap is formed on the upper surface of the rough frame, sediment, dirt, and the like are prevented from being deposited on the upper surface of the frame.

In addition, this artificial reef has a lake, swamp,
It can be installed and installed on revetments such as rivers to demonstrate its function.

[Brief description of the drawings]

1 and 2 are a perspective view and a side view of an artificial reef according to the present invention, and FIGS. 3, 4 and 5 are side views showing examples of different shapes of the artificial reef. 1 ... frame, 2 ... corner, 3 ... artificial flocking board, 4 ...
Gap, 5: fixed joint, 6: flat plate.

Claims (1)

(57) [Claims] 1. An artificial reef installed underwater for protecting a freshwater fish larva, wherein two frame surfaces intersect at an acute angle on an upper surface, and a narrow space is continuously narrowed from a wide space at a lower end thereof. An artificial protective reef for a kindergarten, characterized by having a trough-shaped corner portion, an upper surface of the frame body being rough, and having a large number of continuous fine gaps on the upper surface of the frame body.