JPH0272817A - Fish reserve mounted on sea bottom - Google Patents

Abstract

PURPOSE:To provide the subject fish reserve capable of culturing and breeding fry and spat of benthonic fish and shellfish in a sea area having rapid water stream by joining a prescribed number of straight or bent trapezoidal frame bodies at the side edges and assembling the joined construction into a specific structure. CONSTITUTION:Three or more trapezoidal frame bodies 2 are bonded with each other at the side edge to form a fish reserve frame 1 having a truncated pyramidal or truncated conical form. A lattice 3 is attached to the opened side opening. The inclination angle of the side face is 30-60 deg. based on the bottom face. A binding rope 5 is attached to the edge part and a feeding pipe 6 is attached to the center of the truncated plane.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to a bottom-dwelling structure that can safely grow and culture juveniles of benthic fish and shellfish that have been artificially or naturally collected in sea areas with excellent seawater exchange. This is related to the type fish tank.

(Conventional technology) In recent years, managed fisheries known as ``creating and growing'' have emerged and become popular.
Many years have passed, and the cultivation of fish and shellfish in cages has become very popular and has been carried out over a wide area. With the advancement of aquaculture technology, the number of types of fish and shellfish that can be used has increased, and even bottom-dwelling fish such as flounder are now being farmed. However, unlike the habits of migratory fish, bottom-dwelling fish need to constantly have their abdomens in contact with stable sand or boards, so they have mainly been cultured in pens on land. Studies have been conducted to install bottom-built fish cages in sandy areas with good tidal flow, but these methods lack sufficient structural strength to withstand waves and currents, or the drifting sand is too strong, causing fish injuries and death. In shallow, manageable waters, it has been difficult to adequately respond from an engineering perspective.

(Problems to be Solved by the Invention) The present invention provides a method for safely cultivating juveniles of benthic fish and shellfish, etc., which are artificially or naturally collected, in sea areas with excellent seawater exchange, and which has excellent durability. The aim is to provide fish preserve facilities.

(Means for Solving the Problems) The truncated pyramids and truncated cones, which are the basis of the fish cage facility of the present invention, are used as installed fish reefs. It has been proposed as a built-in fish reef in No. 134589/1983. However, there is no suggestion at all of surrounding the interior of the space with a net and using it as a bottom-built fish tank.

Such a truncated pyramid or truncated cone basically has less resistance to waves and currents than a shaped structure having a face or ridge that is perpendicular to the seabed surface. for example,
Example 1 has a resistance coefficient (CD value) of 2.0 on the upright surface.
An experimental value of 1.55 was obtained for the hexagonal truncated pyramid shown in , which is expressed as a clearly significant difference. It is well known that as the number of angles in a polygon increases, the fluid resistance of that shape decreases, and this value is the minimum value in a truncated cone.

The bottom-built fish cage of the present invention has three or more straight or curved frame-like trapezoidal frames joined together at their side edges to form a truncated pyramidal or truncated conical shape, and the angle of inclination of the side surface with respect to the bottom surface is 30 to 30. 60
It is assembled and formed so that The frame-like trapezoidal frame mentioned above is designed to be able to attach a lattice body and a face piece.
If necessary, it is preferable to provide a lattice body or a face piece on the side surface and the truncated horizontal surface of the truncated pyramidal or truncated conical cage frame. This lattice body or face piece has the effect of reinforcing the net attached to the inside of the fish cage frame and preventing the inflow of drifting sand.

Most bottom-built fish cages are designed with a water depth of about 1 liter to ensure stability.
Traditionally, they are installed in the sea at a depth of about 0m, and compared to normal floating fish tanks, it is extremely difficult to manage them properly, so a structure that saves labor as much as possible is required. The truncated pyramidal and truncated conical structures of the present invention, which are desirable and less susceptible to external forces from such surfaces, are excellent. In addition, since the main purpose is for benthic fish, the storage capacity is proportional to the flat area of the cage, that is, the bottom area, and it is possible to achieve both the above-mentioned engineering stability and economic efficiency. be.

The straight or curved frame-shaped trapezoidal frame serving as the basic member may be made of any structural material such as reinforced concrete, steel, or plastic. From the viewpoint of stability such as sliding against waves and currents, it is better to have a large self-weight.
It is obvious that a material with good rust prevention properties is desirable from the viewpoint of durability.

On the seabed with good tidal flow, in addition to the stability of the cage itself, the influence of sand drift caused by waves and tidal currents cannot be ignored. In other words, fish and shellfish that are being cultivated are naturally susceptible to damage from sand drift, and in cases of severe sand drift,
We need to find ways to avoid this. For this purpose, in the truncated pyramid and truncated cone of the present invention, it is possible to make the bottom edge of the frame-like trapezoid frame high, or to provide a shielding plate at the lower part of the trapezoid inner edge. , fish and shellfish can take shelter behind these alluvial barriers.

Furthermore, this shielding plate is effective in preventing the fish tank from being buried in sand or being washed away.

If necessary, for example, reinforcing pillars for fish pen nets or shading plates can be attached to the inner edge of the truncated head, and feed, etc. can be fed from the sea surface to this inner edge using a pipe. can. In addition, since it is usually easiest to rearrange or recover stored fish and shellfish from the inner edge of this truncated head, problems tend to occur when the opening diameter is too small.

The bottom of the truncated cone may be flat, and in this case, the bottom area can be particularly large to prevent consolidation settlement in soft ground.

In addition, in the case of a truncated pyramid, the lower end of the ridge may be made to protrude from the lower side of the side surface, and when the tip is made flat, the protruding portion of the lower end of the ridge supports the seating impact during installation, and the bending moment is On the other hand, since the seating impact does not directly act on the relatively weak and long lower sides of the sides, damage during sinking is unlikely to occur. In addition, after seating, the tip of the ridge gradually sinks into the seabed, creating a so-called pile effect that significantly improves the ability of the cage to prevent sliding.

A surrounding net is attached to the inside of the truncated pyramidal or truncated conical fish cage frame, but this surrounding net may be attached to the frame of the fish cage frame in advance, and the inner edge of the frame-like trapezoidal frame may be attached to the cage frame in advance. Various means can be used, such as fixing to a lattice frame or locking hook that is previously attached or embedded in the section. Preferably, the mounting and enclosure net are removably attached.

(Example) Hereinafter, this will be explained in detail using examples.

Example 1 As shown in Fig. 1, a truncated hexagonal pyramidal fish cage frame l is assembled by joining the side edges of six frame-like trapezoidal frames 2, and FRP (fiber reinforced plastic)
The lattice body 3 made of

In order to join the six frame-like trapezoidal frames 2, they are fastened with bolts passing through the side edges of the adjacent frames to form the fish cage frame l. The truncated hexagonal pyramidal stacked ends of the fish cage frame 1 protrude downward from the lower sides of the side faces, forming so-called six legs whose bottoms are flat.

The circumference m4 has a mesh size of 60InI11. A synthetic fiber with a silk thread thickness of 4 is used, and a truncated hexagonal pyramid shape is sized so as to be in contact with the inner surface of the fish cage frame 1. A rope 5 for fastening to the fish cage frame 1 is provided at the ridge of the corner. A feeding vibro is attached to the center of the truncated plane.

The bottom side of this fish tank is 5.18 m, and the total width (1
) is 10.36 m, the total width (2) is 8.97 m, the inclination angle between the side and bottom is approximately 45°, the height to the truncated head is 2.4 m, and the weight is approximately 22 tons, volume 10
It is a little over 0M.

Example 2 As shown in Fig. 2, the side edges of four zinc-plated steel picture frame-like trapezoidal frames 2'' are joined to form a truncated four-pyramidal cage frame 1'', and the frame is opened. In the four side openings,
Attach two reinforcing frame rods 7 to each side, and attach them to the lower part of the open side part with a hinge 9 across the width of the FRP shielding plate closing plate 8. When the current is large, the fish cage frame 1 is used to adjust the flow of the current. The shielding plates 8 on the upper side in the direction stand up to block drifting sand, and the shielding plates 8 on the lower side in the flow direction are laid down, so that when the current is small, all the shielding plates 8 are laid down. 4
To join two picture frame-like trapezoidal frames 2°, fasten them with bolts passing through the side edges of the adjacent picture frame-like trapezoidal frames 2'',
Form the fish cage frame l.

The surrounding mesh 4'' is made of galvanized wire mesh with a mesh size of 50 mm, 4q thread thickness and 3.2 barrels, and is firmly fixed to a 2° steel frame-like trapezoidal frame using fasteners and 12 mm coated wire.4.
A reinforcing vibrator IO is provided at one corner of the rectangular square cut-off head, and a feeding vibrator is attached inside the reinforcing vibrator IO.

In addition, this fish tank is in the shape of a four-sided truncated pyramid with a side of the bottom of 5.0 m, a side of the truncated head of 3.0 m, and a height of 2.0 m.
The total weight of the cage, including the weight of the wire mesh, is approximately 12 tons.

Although the first embodiment does not show the shielding plate 8 provided as in the second embodiment, in the first embodiment also, the shielding plate is provided in the same manner as in the second embodiment, so that it operates in the same way. It is preferable to do so.

can do. When the fish cage of Example 1 was installed on a sandy seabed at a depth of 25 m, it did not require any auxiliary mooring (it did not move due to waves or currents, and it did not bury itself in the sand or scour over a length of #11). .

There is one flounder with a body length of 150-200 mm in the fish tank.
00 fish were cultivated on a trial basis, and feeding was carried out using an outboard motor through a feeding vibro from a feeding port floating above the sea surface.
Even after four months have passed, underwater monitoring shows that they have grown uniformly to a length of about 300mm, and are growing very smoothly.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a truncated hexagonal pyramid-shaped bottom-built fish tank made of reinforced concrete according to Example 1, and Fig. 2 is a perspective view of a bottom-built fish tank made of galvanized steel and has a truncated four-sided pyramid shape according to Example 2. be. (Effects of the Invention) The bottom-built fish tank of the present invention has excellent durability, and can safely grow and culture juveniles of benthic fish and shellfish collected artificially or naturally in sea areas with excellent seawater exchange. 1'... Fish cage frame 2,2゛... Frame-shaped trapezoidal frame 3... Lattice body 4,4°... Surrounding net 5... Tightening rope 6.6゛... For feeding Pipe 7...Reinforcement frame rod, shielding plate, hinge 10...Reinforcement pipe Figure 1

Claims (1)

[Claims] A truncated pyramid or truncated cone made by assembling three or more frame-shaped trapezoidal frames with their side edges joined together to form a truncated pyramid or truncated cone with an angle of inclination of the sides to the bottom of 30 to 60°. A bottom-built fish tank with a removable enclosure net attached to the inside of the fish tank frame.