JPH0218809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a floating spawning reef for aquatic plants that is useful for the spawning, growth, and reproduction of fish and shellfish in rivers and lakes, and on which natural aquatic plants and algae can easily attach and flourish. .

Traditionally, with the development of lakes, sea areas, and river coasts, the withering and decreasing of fish and shellfish along these coasts has become a major problem from the perspective of securing fishery resources.As a means to solve this problem, various types of Artificial algae and artificial fish reefs have attracted attention, and examples of the former include Japanese Patent Publication No. 1983-9988 and Japanese Utility Model Publication No. 61092/1983, and examples of the latter include Japanese Patent Publication No. 44-26897 and Japanese Patent Publication No. 5835/1983. Many proposals have been made, including various publications.

However, artificial seagrass and algae are generally used as supplementary materials for fish reefs, and are rarely used alone, and even if they provide a temporary habitat or spawning ground for fish, they do not last long. It has the disadvantage that it is not effective for the habitat, spawning, and reproduction of fish, and as a result, it ends up as garbage in rivers or lakes. In addition, the latter type of artificial reef mainly provides a habitat for fish in the sea, and due to its size and equipment, it requires a huge amount of cost to install and is difficult to construct as a spawning reef in rivers and lakes. Moreover, compared to their size, they are not necessarily effective as spawning reefs in rivers and lakes. In other words, aquatic plants such as natural aquatic algae and aquatic plants that have been lost due to coastal development of rivers and lakes play an extremely important role as spawning reefs for fish in rivers and lakes. Fish living in rivers and lakes rely on plants to feed, spawn, reproduce, and grow, and the growth of such natural aquatic plants,
It can be said that the effects of conventional fish reefs that do not take breeding into consideration are often unsatisfactory in practical terms.

The present inventors have conducted extensive research into floating spawning reefs, which are easy to plant and effective for the growth of natural aquatic plant rhizomes essential for fish spawning, and which, as a result, exhibit performance comparable to natural spawning reefs. The present invention was discovered through development.

That is, the object of the present invention is to easily plant sprouts and rhizomes of emergent plants such as reeds and sagebrush, aquatic plants, and other natural aquatic plants that are necessary for foraging and spawning of fish. To provide a floating spawning reef in which aquatic plants can easily grow and flourish, and the aquatic plants are less likely to be damaged by wind and waves. Another objective is to create a floating type plant that is easy to install on the coasts of rivers and lakes, can be installed at a relatively low cost, and can suppress the death of planted aquatic plants even when the water area fluctuates. Located in providing a floating spawning reef. Further objects will become apparent from the detailed description below.

The object of the present invention is to provide a support frame body composed of at least rod-shaped bodies having an excess buoyancy of about 1 to 30 kg/ ^m2 , which is floating on the water surface, and inside the support frame body, there is a Approximately 2 to 20 cm thick, consisting of entangled monofilament threads with a diameter of 0.2 to 10 mm.
An epiphytic bed consisting of a laminate made of porous sheets having an apparent density of about 0.01 to 0.5 g/cm ³ is engaged, and the epiphytic bed has rhizomes of aquatic plants between the laminate layers. This is accomplished with floating spawning reefs that are sandwiched between With this structure, the epiphyte bed can be used to plant rhizomes of aquatic plants, fix and hold the rhizomes of aquatic plants, and have sufficient durability against waves and wind waves even after the plants have grown. This has been achieved with sheet-like materials having a specific porous structure that provides

That is, one of the features of the floating spawning reef of the present invention is that the rhizomes of natural aquatic plants can be easily planted, without hindering the growth of the planted aquatic plants, and without hindering the growth of the plants. The thickness is approximately 0.2 to 10 mm in order to firmly hold the rhizome, minimize damage from waves and wind and flood damage, and prevent the plant from falling off or dying.
Thickness of approximately 2-20 mm made of monofilament yarn
cm, and an apparent density of about 0.01 to 0.5 g/cm ³ is used as an epiphyte bed for the aquatic plants.

The monofilament yarns constituting this porous sheet material include polyolefin, polyamide,
Examples include those made of various known synthetic polymers such as polyester, polyvinyl chloride, polyvinylidene chloride, and polyvinyl alcohol. The entangled body of the present invention is a non-woven porous sheet made by intertwining such monofilament yarns, and this non-woven sheet may be bonded with an adhesive or heat-sealed as the case may be. Good too. A plurality of such sheet-like materials constitute the epiphyte bed of the present invention in the form of a laminate.Since the floating spawning reef of the present invention is installed in a natural environment such as a river or lake, the filamentous material is It not only forms an epiphytic bed that has sufficient strength to withstand wind and flood damage and has sufficient flatness, but also does not hinder the growth of the rhizomes of aquatic plants planted in the epiphytic bed and intertwine with the rhizomes. It needs to be firmly fixed. From this point of view, the thickness of the monofilament yarn is 0.2 to 10 mm,
Preferably, it is as rigid as possible within the range of 0.3 to 5 mm.

The apparent density of the porous sheet-like material made of such filamentous material is determined by the same reasons as those of the filamentous material mentioned above, as well as the density of the rhizomes of aquatic plants such as reeds and mamoko to be planted on the floating spawning reef of the present invention. The thickness is usually about 1 to 3 cm in diameter, so when planting such aquatic plants, the diameter is about 0.01 to 0.5 cm, taking into account workability, accumulation of floating mud on the epiphyte bed, and fish nest effect. g/cm ³ , preferably in the range of about 0.02 to 0.1 g/cm ³ . That is,
If the apparent density is less than about 0.01 g/cm ³ , it may become difficult to stably plant the rhizomes of aquatic plants, the fixation and retention of the aquatic plants may become insufficient after they have grown, or the accumulation of floating mud may occur. As a result, the growth of aquatic plants becomes poor. On the other hand, if it exceeds about 0.5 g/cm ³ , the workability in planting rhizomes of aquatic plants decreases, the accumulation of floating mud becomes too significant, and weight increase and root rot tend to occur, which is not preferable.

In addition, the thickness of this porous sheet-like material is about 2~
20 cm, preferably about 5 to 10 cm. If the thickness becomes thinner than about 2 cm, it will be difficult to stably support and fix the aquatic plants planted in the epiphytic bed as they grow. Become. On the other hand, if the thickness is greater than about 20 cm, the rhizomes of aquatic plants will grow to the bottom of the epiphyte bed and will be hindered from flourishing, and the effect of promoting spawning, feeding, and growth of fish will not be fully exerted, and the roots of This is not preferable because it tends to rot. In particular, the floating spawning reef of the present invention allows the rhizomes of aquatic plants to grow and flourish in the water below the epiphyte bed, and provides a habitat for fish to spawn on these rhizomes, form fish nests, and forage on the rhizomes. From this point of view, its thickness is important.

Next, as a support frame body that engages and supports the epiphyte bed made of a laminate of entangled bodies, it is possible to cover the epiphyte bed as much as possible and to mechanically firmly engage the epiphyte bed. For example,
For example, rod-shaped bodies such as rods and pipes made of synthetic resins such as polyethylene, vinyl chloride, ABS, polyamide, and polyester, and in addition to these, frames assembled as appropriate using ropes obtained from the various synthetic fibers mentioned above; There are nets etc.

However, the supporting frame constituting the floating spawning reef of the present invention has an excess buoyancy of about 1 to 30 Kg/m ² ,
It is preferably 5 to 20 kg/m ² . That is, the surplus buoyancy is for floating the support frame (frame surface) and the epiphyte on the water surface. For example, a buoyancy body may be attached to the frame, but it is particularly preferable that the surplus buoyancy be applied to the entire support frame. In order to make the frame surface float horizontally by uniformly imparting buoyancy, the frame itself is made to have buoyancy. For example, the first
An embodiment in which the rod-shaped fixture 1 and the rod-shaped body 2 shown in the figure are made of a buoyant material, such as a foam, is preferably applied. As will be described later, the floating spawning reef of the present invention is normally installed at a location at least 20 cm below the water surface. If it is smaller than ² , the epiphyte beds covered with aquatic plants will settle due to the adhesion of aquatic organisms and the accumulation of sludge, resulting in the death of natural aquatic plants.

On the other hand, if the surplus buoyancy is greater than about 30 kg/m ² , the above-water portion of the support frame will be exposed at a high level, which will impair the durability of the material and cause natural aquatic plants to wither. However, if the supports and epiphytes have extra buoyancy and are moored so that they can follow fluctuations in water level, natural aquatic plants will not wither and water will not stagnate, making effective use of lakes and marshes. This helps improve the environment and the reproduction of fish.

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of the floating spawning reef of the present invention. In the figure, 2 is a rod-shaped body, 1 is a fixture for the rod-shaped body, and 4 is an epiphyte bed. As shown in the figure, the floating spawning reef of the present invention has a rod-shaped body 2 such as a rod or pipe made of various synthetic resins such as polyethylene, polypropylene, polyvinyl chloride, ABS, polyamide, and polyester, and It has a structure in which an intertwined body of monofilament yarns, that is, an epiphyte bed 4, is engaged with the surface of a frame, that is, a support frame, which is fixed by a fixture 1. Further, as shown in the figure, the rod-shaped body 2 may be formed by wrapping a single layer 3 of a porous sheet material around the rod-shaped body 2. Thereby, the rhizomes of aquatic plants can be planted on the rod-shaped body 2, and the aquatic plants grown on the floating spawning reef can be firmly fixed. The support frame that engages the epiphyte bed 4 has an excess buoyancy of 1.0.
Kg/m ² or more, preferably 5 Kg/m ² or more, it has a function as a floating body, retains the rhizomes of aquatic plants planted in the epiphytic bed 4 in water, and causes the aquatic plants to die. can be prevented. However, if the surplus buoyancy of the support frame is too large, the epiphyte will be exposed above the water surface, hindering the growth of the planted aquatic plants, and making the epiphyte easy to deteriorate.
Anything exceeding Kg/m ² is not preferred.

FIG. 2 is a partially cutaway cross-sectional view of a single sheet layer constituting the epiphyte bed, showing that it has a nonwoven fabric-like structure in which monofilament yarns are intertwined with each other and integrated.

FIG. 3 is a perspective view with the laminate partially peeled off to show the state in which the rhizomes of aquatic plants are held in the epiphytic bed. This makes it possible to increase the shading effect under the water surface at the initial stage of installation, and to increase the effect of attracting fish and fish nests.

As a method for installing such a floating spawning reef of the present invention, the floating spawning reef can be moored near the water surface as it is or by attaching a floating body as appropriate, in accordance with a known method for installing a floating spawning reef. The best water depth for floating spawning reefs to be installed is for the epiphyte bed to be approximately 20 cm from the water surface.If the water depth exceeds 20 cm, the young shoots of aquatic plants planted on the epiphyte bed may be baited by fish.
Insufficient light transmission inhibits the early growth of the plant, which is undesirable, and when it rises above the water surface, the epiphyte bed is exposed to strong sunlight and may deteriorate in a short period of time, which is undesirable.

In addition, by covering the entire surface of the floating spawning reef of the present invention installed underwater with various known nets or rods arranged in a grid pattern, the aquatic plants planted on the floating spawning reef can grow. The fixation of aquatic plants after washing can be greatly improved.

Furthermore, the porous sheet-like material serving as the epiphytic bed constituting the floating spawning reef of the present invention does not need to be provided over the entire epiphytic bed, which increases the effects of fish nests and spawning reefs, and reduces installation workability and maintenance management. To facilitate
An epiphyte bed with dimensions of approximately 0.25 to 4 ^m2 is placed on a support frame of 0.5 to 4 m2.
Can be installed partially at 2m intervals.

Features of the present invention (1) During the spawning season for fish, aquatic plants always grow and provide a clean spawning ground every year.

(2) Because it is a floating type, it follows fluctuations in water level, does not kill aquatic plants, and does not interfere with lakes or ocean currents.

(3) Provide a semi-permanent spawning ground without being buried in the lake bottom.

(4) Helps improve the environment and water quality of lakes and marshes.

(5) No maintenance required.

(6) Can be installed at low cost.

(7) It is possible to create fields with limited species of aquatic plants, making it easier to utilize aquatic plants as resources.

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

Example 1 An ABS rod with a diameter of 10 cm and a length of 2 m is fitted into a 45 cm x 6.5 cm block made of polyethylene resin, and the rod doubles as a floating body of 5 Kg/m, with an excess buoyancy of 20 Kg/m. A frame in the form of ^{a two-} dimensional grid was created as a support frame. On the other hand, a random entangled body with an apparent density of 0.05 g/cm ³ was prepared from approximately 4000 denier nylon monofilament threads (thickness approximately 0.7 mm), and the contact points between the monofilament threads were bonded by heating and pressing. An epiphyte bed was prepared by laminating two entangled sheets with a thickness of 5 cm, which were attached to the grid-shaped frame.
A floating spawning reef shown in the figure was constructed.

On the epiphyte bed, a large number of underground rhizomes of reeds and japonicas collected from the shore of the lake and cut into approximately 20 cm lengths were planted at intervals of approximately 10 cm between the layers of the sheet material.

The planting operation includes a method of making a hole in the sheet layer between layers other than the surface layer of the laminate constituting the epiphytic bed, and inserting underground rhizomes of reeds and cypress into the holes;
A method was adopted in which the material was held between the sheets of the epiphyte bed, and in addition to this method, a method was adopted in which the material was held between the sheets and a reinforcing net on the epiphyte bed. Floating the floating spawning reef at a position 50 cm offshore from the shore of the lake and 3.5 m deep,
For about 8 months from February to September, we observed the growth of reeds and Japanese jackfruit.

From early spring to autumn, fish swarm in the lake around the floating spawning reef, and during the spawning season, many fish eggs were seen on the underground stems, roots, and leaves of aquatic plants. From then until autumn, the reef was exposed to winds of about 20 m/sec and waves of about 1.5 m in height, but there was no problem with the floating spawning reef and the flourishing of natural aquatic plants.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing one example of the floating spawning reef of the present invention, and FIG. 2 is a partially cutaway sectional view of a single sheet layer (entangled body) constituting the epiphyte bed of the present invention. FIG. 3 is a partially peeled perspective view showing the state in which the rhizomes of aquatic plants are held in the epiphyte bed of the present invention. 1: Fixture of rod-shaped body, 2: Rod-shaped body, 3: Single sheet layer of porous sheet material, 4: Epiphyte bed (laminate), 6: Rhizome of aquatic plant.

Claims (1)

[Claims] 1. A support frame composed of at least rod-shaped bodies having an excess buoyancy of about 1 to 30 Kg/m ² is floating on the water surface, and inside the support frame is mainly a monofilament with a thickness of 0.2 to 10 mm. The thickness is approximately 2 to 20 cm and the apparent density is approximately 0.01 to 20 cm.
An epiphytic bed made of a laminate made of porous sheets of 0.5 g/cm ³ is engaged, and the epiphytic bed has rhizomes of aquatic plants sandwiched between the laminate layers. Features a floating spawning reef.