Seaweed bed growth reef

Abstract

To provide a seaweed bed growth reef capable of protecting seaweed against damage by fishes eating seaweed without being covered with a basket or net.SOLUTION: An imitation rock unit 7 serving as a scaffold of seaweed 2b is provided. A vicinity of the imitation rock unit 7 is provided with a bigfin reef squid egg production substrate 10 in which a bigfin reef squid 9 that eliminates fishes eating seaweed 8 is allowed to live. The fishes eating seaweed 8 is eaten by the bigfin reef squid 9 or goes away. The fishes eating seaweed 8 is eliminated from the vicinity of the imitation rock unit 7 without being covered with a basket or net. The seaweed 2b having the imitation rock unit 7 as a scaffold is protected against a damage by the fishes eating seaweed 8.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a seaweed bed proliferation reef that promotes the growth of seaweed and proliferates seaweed beds. [Background technology]

[0002] Generally, seaweed beds provide hiding places and spawning sites for fish, crustaceans and other marine organisms. In addition, the seaweed and the microscopic algae attached to it absorb nutrients such as nitrogen and phosphorus to purify the water, and also supply oxygen to the ocean through photosynthesis.

[0003] However, in coastal waters where seaweed grows abundantly and forms seaweed beds, a phenomenon known as "shore denudation" occurs, in which the seaweed decreases or disappears significantly, which can deal a major blow to coastal fisheries.One of the causes of coastal denudation is said to be damage caused by algae-eating fish such as parrotfish, barracudas, and rabbitfish.

[0004] In response to this, for example, Patent Document 1 discloses a seaweed reef in which a substrate on which seaweed shoots grow is attached to a main body and this is covered with a shoot protection cage.

[0005] The seaweed reef in Patent Document 1, when placed on the seabed, can prevent the intrusion of herbivorous fish with a seedling protection cage, protecting the seedlings from being eaten, while allowing the seedlings attached to the substrate to grow into adults.This seaweed reef can serve as a nucleus for the release of spores from the adult seaweed, forming a seaweed bed in the surrounding area. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP-A-59-173031 (column 7, line 12 to column 8, line 3, column 12, line 2 to line 8, column 12, line 16 to column 13, line 4) Summary of the Invention [Problem to be solved by the invention]

[0007] However, the algal reef in Patent Document 1 prevents the invasion of herbivorous fish by covering the core algal reef with a juvenile protection cage. Problems can arise regarding the durability of the juvenile protection cage, as well as deterioration of the light environment surrounding the seaweed due to clogging of the cage, necessitating regular maintenance such as removing attached matter.

[0008] To provide a seaweed bed proliferation reef capable of protecting seaweed from damage caused by herbivorous fish without covering it with a cage or net. [Means for solving the problem]

[0009] In order to achieve the above-mentioned objective, the seaweed bed proliferation reef of the present invention is for promoting the growth of seaweed and proliferating seaweed beds, and is provided with a seaweed bed proliferation substrate that serves as a foothold for seaweed, and a carnivorous fish and shellfish habitat substrate is provided near this seaweed bed proliferation substrate for allowing carnivorous fish and shellfish to live there and exclude algae-eating fish.

[0010] According to the above configuration, a habitat substrate for carnivorous fish and shellfish is provided near the seaweed bed growth substrate for allowing carnivorous fish and shellfish to live there. The carnivorous fish and shellfish prey on or chase away the algae-eating fish, thereby eliminating the algae-eating fish from the vicinity of the seaweed bed growth substrate without covering it with a cage or net, and protecting seaweed that uses the seaweed bed growth substrate as a foothold from being eaten by the algae-eating fish.

[0011] The seaweed bed growth substrate can also be made up of a plurality of artificial rock units spaced apart from one another around the carnivorous fish and shellfish habitat substrate.

[0012] According to this configuration, the artificial rock units with a surface shape similar to that of a natural reef are used as the substrate for the growth of the seaweed bed, and the complex unevenness of the rocks increases the rate of settlement of the seaweed zoospores and increases the adhesive strength of the rhizoids after settlement, making them less likely to be washed away. Moreover, since multiple artificial rock units are placed at intervals around the habitat substrate for carnivorous fish and shellfish, the seaweeds can be separated from each other and can grow sufficiently.

[0013] In addition, the main reef, which has a seaweed bed growth substrate and a habitat substrate for carnivorous fish and shellfish, may be used as a nucleus seaweed bed in which seaweed grows abundantly and supplies zoospores, and extended reefs, which have a seaweed bed growth substrate but no habitat substrate for carnivorous fish and shellfish, may be placed at intervals around the main reef.

[0014] With this configuration, the main reef, which has a seaweed bed growth substrate and a habitat substrate for carnivorous fish and shellfish, serves as a core seaweed bed, and sufficient zoospores can be supplied from the seaweed that grows in this core seaweed bed. This allows seaweed to grow in abundance in locations away from the main reef by placing an expansion reef around the main reef, which is simply a seaweed bed growth substrate, and furthermore, a wide-area seaweed bed can be formed that extends around the expansion reef. Effect of the Invention

[0015] As described above, according to the present invention, a habitat substrate for carnivorous fish and shellfish is provided near the seaweed bed growth substrate of a seaweed bed growth reef, and the carnivorous fish and shellfish living in the habitat substrate prey on or chase away the algae-eating fish. This makes it possible to protect seaweed that uses the seaweed bed growth substrate as a foothold from damage caused by the algae-eating fish without covering it with a cage or net, and allows the seaweed bed to grow without requiring special maintenance. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a seaweed bed reef according to the present invention; [Diagram 2] Perspective view of the reef [Diagram 3] Cross-section of the reef [Figure 4] A diagram showing how Bigfin Reef Squid protects seaweed from damage caused by herbivorous fish. [Diagram 5] Perspective view of an extended reef [Figure 6] A perspective view of another type of reef DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the seaweed bed proliferation reef according to the present invention will be described with reference to the drawings.

[0018] As shown in Figures 1 to 5, in a seaweed bed proliferation reef 1, a main reef 3 is installed on the seabed as a nucleus seaweed bed for protecting and growing seaweeds 2a, 2b, and a number of extended reefs 4 are placed at intervals around the main reef 3, on which zoospores 5 released by the seaweeds 2a, 2b protected by the main reef 3 are attached to grow new seaweed 2c, thereby supplying a sufficient amount of zoospores 5 released by the new seaweed 2c to the areas around the main reef 3 and extended reef 4, causing the seaweed 2 to flourish over a wide area of ​​the seabed and proliferating the seaweed bed 6. On the main reef 3, artificial rock units 7 are provided as a seaweed bed proliferation substrate to provide a foothold for the seaweed 2b, and a spawning substrate 10 is provided as a habitat substrate for carnivorous fish and shellfish in which the bigfin reef squid 9, a carnivorous fish and shellfish, lives and which excludes algae-eating fish 8 from the vicinity of the seaweed bed proliferation substrate 7.

[0019] Here, the seaweed 2a, 2b, 2c, and 2 can be exemplified by Eisenia bicolor, and the herbivorous fish 8 can be exemplified by Rabbitfish, but are not limited thereto. Also, the carnivorous fish and shellfish can be exemplified by Bigfin reef squid 9, but are not limited thereto.

[0020] As shown in Figures 2 and 3, the reef 3 has a squid spawning substrate 10 in the center of a three-dimensional lattice-shaped steel frame 12 whose lower part is covered with a weighted concrete 11, and the upper part of the steel frame 12 around the squid spawning substrate 10 is covered with two concrete panels, one large and one small, 13a, 13b, and four artificial rock units 7 are fixed to the upper surfaces of the concrete panels at intervals.

[0021] The ovarian squid spawning substrate 10 has a structure in which multiple shafts 15 protrude upward from a plate 14, and the peripheral portion of the plate 14 is placed on and fixed to four angle irons 17 that are suspended between four support pillars 16 erected so as to surround the center of the steel frame 12, allowing the ovarian squids 9 to migrate there and easily spawn. The height of the ovarian squid spawning substrate 10 is set so that the upper ends of the shafts 15 are positioned slightly below the concrete panels 13a, 13b, reducing the effects of waves and allowing for relatively inexpensive production.

[0022] As shown in Fig. 4, multiple axes 15 are densely packed in the spawning substrate 10 for the bigfin reef squid, preventing the algae-eating fish 8 from swimming freely, and allowing the seaweed 2a to grow without being eaten. Moreover, the bigfin reef squid 9, which preys on the algae-eating fish 8, comes to and lives in the spawning substrate 10 for the bigfin reef squid, making the growth of the seaweed 2a even more reliable.

[0023] Zoospores 5 are released from the seaweed 2a that has grown on the oval squid spawning substrate 10, which attach to the artificial rock unit 7 located nearby and grow seaweed 2b. Herbivorous fish 8 that approach to eat the seaweed 2b are either preyed upon by the oval squid 9 that inhabit the oval squid spawning substrate 10 or escape, so that the herbivorous fish 8 are excluded from the vicinity of the artificial rock unit 7, and the seaweed 2b is protected and allowed to grow sufficiently.

[0024] By releasing a sufficient amount of zoospores 5 from the seaweed 2a, the seaweed 2b will grow sufficiently even if the bigfin reef squids 9 do not remove all of the herbivorous fish 8 from the vicinity of the artificial rock unit 7, for example, if the bigfin reef squids 9 are temporarily absent from the spawning substrate 10.

[0025] A sufficient amount of zoospores 5 are released from the seaweed 2b, which attach to multiple extension reefs 4 around the main reef 3 and grow new seaweed 2c.

[0026] As shown in Figure 5, the extended reef 4 has artificial rock units 18 as a seaweed bed growth substrate that serves as a foothold for seaweed 2c without providing a spawning substrate for bigfin reef squid. The upper part of a three-dimensional lattice-shaped steel frame 20, the lower part of which is covered with weight concrete 19, is covered with a concrete panel 21, and four artificial rock units 18 are fixed to the upper surface of the frame at intervals.

[0027] A sufficient amount of zoospores 5 released from the seaweed 2b growing on the main reef 3 attaches to the artificial rock unit 18, so that even if some of the seaweed 2c is eaten by the herbivorous fish 8, a sufficient amount of seaweed 2c will grow, and further, a large amount of zoospores 5 will be released into the surrounding area to attach over a wide area of ​​the seabed, thereby causing the seaweed bed 6 to proliferate.

[0028] The main reef 3 and the extended reef 4 have seaweed 2a growing on the spawning substrate 10 for the bigfin reef squid supported by four angle irons 17 suspended between four support columns 16, and the seaweeds 2b, 2c growing on the artificial rock units 7, 18 arranged on the top of the steel frames 12, 20, which prevents damage to the seaweeds 2a, 2b, 2c by sea urchins crawling along the seabed. The main reef 3 and the extended reef 4 also function as breeding reefs for fish and shellfish other than the bigfin reef squid 9, such as for spear squid spawning on the undersides of the concrete panels 13a, 13b, 21 and the plate 14, and for protecting and raising juvenile fish such as rockfish in the space below.

[0029] The present invention is not limited to the above embodiment, and appropriate modifications may be made within the scope of the present invention. For example, as shown in Fig. 6, the main reef 22 may be configured such that the upper end of the axis 25 is set higher than the surrounding seaweed bed growth substrate 26 by raising the mounting position of the plate 24 of the central oval squid spawning substrate 23, so that the oval squid can easily find the oval squid spawning substrate 23 and that the tidal flow and light environment of the oval squid spawning substrate 23 are improved to promote the growth of seaweed. The choice of whether to raise the oval squid spawning substrate 23 as in the main reef 22 or to lower the oval squid spawning substrate 10 as in the main reef 3 of Figs. 2 and 3 may be selected taking into consideration the conditions of the sea area in which they are installed and the economics.

[0030] In Fig. 6, 27 is an oyster shell that functions as a food culture for the fish protected and raised by the reef 22. Also, 28 is a tidal channel that supplies fresh seawater to the spawning substrate 23 for the bigfin reef squid and reduces the accumulation of floating mud.

[0031] The length of the axis of the spawning substrate for the bigfin reef squid may be selected depending on the type of seaweed to be grown. For example, for large brown algae such as Eisenia bicolor and Ecklonia cava, ascosacs are formed on the lower part of the fronds, even the relatively short axes 15, 25 of the main reef 3 in Figures 2 and 3 and the main reef 22 in Figure 6 can protect the seaweed growing on the spawning substrate for the bigfin reef squid from herbivorous fishes. On the other hand, for species such as Sargassum that grow to 1m or more and release seeds from the top, it is preferable to use a longer axis.

[0032] In addition, the seaweed bed growth reef 1 may be formed not only by using the main reef 3 and the extended reef 4 as a set, but also by using only the main reef 3. Also, the concrete panels 13a, 13b, 21 may be used as the seaweed bed growth substrate without providing the artificial rock units 7, 18. [Explanation of symbols]

[0033] 1. Seaweed bed reef 2, 2a, 2b, 2c seaweed 3 Reef 4. Expansion Reef 5 Zoospores 6 Seaweed bed 7. Artificial rock unit 8 Algae-eating fish 9 Bigfin Reef Squid 10. Bigfin Reef Squid Spawning Substrate 11. Concrete weights 12 Steel frame 13a, 13b Concrete panels 14 Plate 15-axis 16 Support column 17 Angle iron 18 Imitation rock unit 19 Concrete weights 20 Steel frame 21 Concrete Panel 22 reefs 23 Bigfin reef squid spawning substrate 24 Plate 25 Axis 26 Seaweed Bed Growth Substrate 27 Oyster Shell 28 Tidal Channel

Claims

1. A seaweed bed proliferation reef that promotes the growth of seaweed and causes seaweed beds to proliferate, comprising a seaweed bed proliferation substrate that serves as a foothold for seaweed, and a carnivorous fish and shellfish habitat substrate that allows carnivorous fish and shellfish to live in the vicinity of the seaweed bed proliferation substrate, and that excludes algae-eating fish.

2. 2. The seaweed bed proliferation reef according to claim 1, characterized in that the seaweed bed proliferation substrate is a plurality of artificial rock units arranged at intervals around the carnivorous fish and shellfish habitat substrate.

3. A seaweed bed proliferation reef as described in claim 1 or 2, characterized in that the main reef having the seaweed bed proliferation substrate and the carnivorous fish and shellfish habitat substrate is used as a nucleus seaweed bed in which seaweed grows abundantly and supplies zoospores, and extended reefs having a seaweed bed proliferation substrate without providing a carnivorous fish and shellfish habitat substrate are arranged at intervals around the main reef.

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