seaweed bed 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 propagation reef that promotes the growth of seaweed and thereby propagates seaweed beds. [Background technology]

[0002] Generally, seaweed beds provide hiding places and spawning grounds 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 "isoyake" (seaweed bleaching) can occur, causing a significant decrease or disappearance of the seaweed, which can deal a major blow to coastal fishing.One of the causes of this isoeyankee is 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 sprouts grow is attached to a main body and this is covered with a sprout protection cage.

[0005] The seaweed reef in Patent Document 1, when installed on the seabed, prevents the invasion 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 serves 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, and problems can arise with the durability of the juvenile protection cage and the deterioration of the light environment surrounding the seaweed due to clogging of the juvenile protection cage, requiring periodic maintenance such as removing adhesions.

[0008] An object of the present invention is 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 objectives, the seaweed bed growth reef of the present invention is designed to promote the growth of seaweed and thereby grow seaweed beds, and is provided with a seaweed bed growth substrate that serves as a foothold for seaweed, and a carnivorous fish and shellfish habitat substrate is provided near this seaweed bed growth substrate to allow 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, and carnivorous fish and shellfish are allowed to live there.The carnivorous fish and shellfish prey on or drive away the algae-eating fish, thereby eliminating the algae-eating fish from the vicinity of the seaweed bed growth substrate without having to cover it with a cage or net, and protecting the 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] With this configuration, the artificial rock units, which have a surface shape similar to that of natural reefs, are used as the substrate for growing seaweed beds, and their complex unevenness increases the rate at which seaweed zoospores settle, and also increases the adhesive strength of the rhizoids after settling, making them less likely to be washed away. Furthermore, by arranging multiple artificial rock units at intervals around the periphery of the carnivorous fish and shellfish habitat substrate, the seaweed can be spaced apart, allowing each seaweed to grow sufficiently.

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

[0014] With this configuration, the main reef, which contains the substrate for seaweed bed growth and the substrate for carnivorous fish and shellfish habitat, serves as a nucleus seaweed bed, and the seaweed that grows in this nucleus seaweed bed can provide a sufficient supply of zoospores. As a result, by placing an expansion reef around the main reef, which is simply provided with a substrate for seaweed bed growth, it is possible to make seaweed grow in locations away from the main reef, and furthermore, it is possible to form a wide-area seaweed bed that extends around the expansion reef. [Effects 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 are allowed to prey on or drive away the algae-eating fish. This makes it possible to protect seaweed that uses the seaweed bed growth substrate as a foothold from being eaten by the algae-eating fish without covering it with cages or nets, and allows the seaweed bed to grow without requiring special maintenance. [Brief explanation of the drawings]

[0016] [Figure 1] A perspective view of a seaweed bed accretion reef according to the present invention. [Figure 2] Perspective view of the reef [Figure 3] Cross section of the reef [Figure 4] A diagram showing how bigfin reef squid protects seaweed from being eaten by herbivorous fish. [Figure 5] Perspective view of an expanded reef [Figure 6] A perspective view of another type of reef DETAILED DESCRIPTION OF THE INVENTION

[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, a seaweed bed growth reef 1 is constructed by installing a main reef 3 on the seabed as a nucleus seaweed bed for protecting and growing seaweeds 2a and 2b, and by placing zoospores 5 released by the seaweeds 2a and 2b protected by the main reef 3 on multiple extension reefs 4 spaced around the main reef 3, causing new seaweed 2c to grow by attaching them to the main reef 3. This supplies a sufficient amount of zoospores 5 released by the new seaweed 2c to the area around the main reef 3 and extension reefs 4, causing seaweed 2 to flourish over a wide area of the seabed and growing a seaweed bed 6. The main reef 3 is provided with artificial rock units 7 as a seaweed bed growth substrate that provides a foothold for the seaweed 2b, and a spawning substrate 10 as a habitat for bigfin reef squid 9, a carnivorous fish species that excludes herbivorous fish 8 from the vicinity of the seaweed bed growth 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 to these. Also, the carnivorous fish and shellfish is exemplified by Bigfin Reef Squid 9, but are not limited to this.

[0020] As shown in Figures 2 and 3, the reef 3 has a three-dimensional lattice-shaped steel frame 12 with a bottom covered with a concrete weight 11, and a spawning substrate 10 for bigfin reef squids in the center of the frame. The top of the steel frame 12 is surrounded by two concrete panels 13a and 13b, one large and one small, and four artificial rock units 7 are fixed to the top of the panels at intervals.

[0021] The oval 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 oval squid 9 to migrate and easily spawn. The height of the oval squid spawning substrate 10 is set so that the upper ends of the shafts 15 are positioned slightly below the concrete panels 13a and 13b, which reduces the impact of waves and allows for relatively inexpensive production.

[0022] As shown in Figure 4, multiple axes 15 are densely packed in the spawning substrate 10 for bigfin reef squid, preventing the algae-eating fish 8 from swimming freely, allowing the seaweed 2a to grow without being eaten. Furthermore, bigfin reef squid 9, which prey on the algae-eating fish 8, come to and live in the spawning substrate 10, further ensuring the growth of the seaweed 2a.

[0023] Zoospores 5 are released from seaweed 2a grown on oval squid spawning substrate 10, which attach to nearby artificial rock units 7 and grow seaweed 2b. Herbivorous fish 8 that approach to eat this seaweed 2b are either preyed upon by oval squids 9 living on oval squid spawning substrate 10 or escape, thereby excluding herbivorous fish 8 from the vicinity of artificial rock units 7 and protecting seaweed 2b, allowing it to grow sufficiently.

[0024] By releasing a sufficient amount of zoospores 5 from the seaweed 2a, even if the bigfin reef squid 9 does not temporarily inhabit the spawning substrate 10, or if all the herbivorous fish 8 are not eliminated from the vicinity of the artificial rock unit 7 by the bigfin reef squid 9, the seaweed 2b will grow sufficiently.

[0025] A sufficient amount of zoospores 5 is 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 expanded reef 4 does not have a spawning substrate for bigfin reef squid, but instead has artificial rock units 18 as a seaweed bed growth substrate that serves as a foothold for seaweed 2c.The expanded reef 4 is made of a three-dimensional lattice-shaped steel frame 20, the lower part of which is covered with heavy concrete 19, the upper part of which 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 seaweed 2b growing on the main reef 3 attaches to the artificial rock unit 18, and even if some of the seaweed 2c is eaten by herbivorous fish 8, a sufficient amount of seaweed 2c grows, and further, a large amount of zoospores 5 is released into the surrounding area, causing them to attach over a wide area of the seabed and proliferate the seaweed bed 6.

[0028] The main reef 3 and the extended reef 4 are structured so that seaweed 2a grows on the spawning substrate 10 for bigfin reef squid, which is supported by four angle irons 17 suspended between four support columns 16, and seaweed 2b and 2c grows on artificial rock units 7 and 18 placed on top of the steel frames 12 and 20, thereby preventing damage to the seaweed 2a, 2b, and 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 bigfin reef squid 9, such as for spear squid spawning on the undersides of the concrete panels 13a, 13b, 21 and plates 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-described embodiment, and modifications can be made as appropriate within the scope of the present invention. For example, as shown in Figure 6, the reef 22 may be configured such that the mounting position of the plate 24 of the central oval squid spawning substrate 23 is elevated, thereby setting the upper end of the axis 25 higher than the surrounding seaweed bed growth substrate 26. This allows the oval squid to more easily find the oval squid spawning substrate 23 and improves the tidal flow and light environment of the oval squid spawning substrate 23, thereby promoting the growth of seaweed. Whether to raise the oval squid spawning substrate 23 as in the reef 22 or lower the oval squid spawning substrate 10 as in the reef 3 of Figures 2 and 3 can be selected taking into account the conditions and economics of the sea area where they are installed.

[0030] In Figure 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 bigfin reef squid spawning substrate 23 and reduces the accumulation of floating mud.

[0031] The length of the stem of the spawning substrate for the bigfin reef squid may also be selected depending on the type of seaweed being grown. For example, large brown algae such as Eisenia bicolor and Ecklonia cava form sacs on the lower part of their fronds, so even the relatively short stems 15 and 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 from herbivorous fish. On the other hand, for species such as Sargassum, which grow to over 1 meter and release seeds from the top, it is preferable to use longer stems.

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

[0033] 1 Seaweed bed reef 2, 2a, 2b, 2c seaweed 3 reefs 4. Expansion Reef 5 Zoospores 6 Seaweed bed 7. Imitation 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 plates 15 axes 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 plates 25 axes 26 Seaweed Bed Growth Substrate 27 Oyster shells 28 Tidal Channel

Claims

1. A seaweed bed propagation reef that promotes the growth of seaweed and propagates seaweed beds, A carnivorous fish and shellfish habitat substrate is provided in the center of the three-dimensional lattice-shaped steel frame, and the carnivorous fish and shellfish habitat substrate is configured with a plurality of axes protruding upward from the plate, The upper part of the steel frame, surrounding the habitat substrate for carnivorous fish and shellfish, is covered with concrete panels to create a seaweed bed growth substrate that serves as a foothold for seaweed.

2. 2. The seaweed bed proliferation reef according to claim 1, wherein the seaweed bed proliferation substrate comprises a plurality of artificial rock units fixed at intervals on the upper surface of the concrete panel.

3. A main reef that serves as a nucleus bed for growing seaweed and supplying zoospores, and extension reefs arranged at intervals around the main reef, The reef is the seaweed bed proliferation reef described in claim 1 or 2, The expanded reef is a seaweed bed growth reef, characterized by covering the top of a three-dimensional lattice-shaped steel frame with concrete panels without providing a habitat substrate for carnivorous fish and shellfish, and fixing multiple artificial rock units to the top surface at intervals to form a seaweed bed growth substrate that serves as a foothold for seaweed.

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