JP2011125347A - Method for making coral reef - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for making a coral reef, by which the adhesion environment is improved to positively invite coral larvae so that remake of the coral reef is contemplated without using a means such as the transplantation or importation of corals, the glazing by fishes and the like can be prevented after the adhesion, and, even in the sea area low in coral larva recruitment amount such as exhausted coral reef, the coral reef can be formed without a large installation. <P>SOLUTION: Coral larvae are adhered on the rear side of a net-like structure 2, and the net-like structure 2 is reversed and set on at least a part of an adhesion substrate 1 in water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coral reef creation method.

  Coral reefs are a source of biodiversity, play an important role not only in Japan but also overseas, in the culture and economic activities of local communities, and their value for use in medicines is also attracting attention.

  However, global climate change in recent years has caused adverse effects such as whitening due to rising seawater temperature and food damage due to abnormal breeding of the starfish, and mass death is becoming prominent. Coral reefs are in serious danger and there is a need to regenerate lost (depleted) coral reefs. In addition, the early formation of coral reefs on man-made structures is also desired for port construction and new revetment construction.

  Conventionally, coral reefs have been regenerated mainly by transplanting / transferring corals (groups, planula larvae or eggs) collected from outside the sea area to be regenerated, and corals cultivated on the basis of them. Various proposals have been made so far.

  For example, the coral propagation method disclosed in Patent Document 1 is a method for coral eggs and / or floating in a sea area having an epidermis base on which the coral planula larvae (hereinafter sometimes referred to as coral larvae) can grow. Propagation of the coral eggs and / or planula larvae is provided by preventing or suppressing the spread of the planula larvae and dispersing the coral eggs and / or the planula larvae by opening the bottom and preventing the planula larvae from sinking to settle on the growth base. Alternatively, by putting the seawater in which these float in the area into the area surrounded by the diffusion prevention means, the area becomes a high concentration area of coral eggs and / or planula larvae and is maintained for a certain period. The coral planula larvae are grown on the raw base.

  When regenerating coral reefs, there is a method of forming irregularities on the surface of the structure for coral deposition on the substrate (structure), and it is effective to set the size of the irregularities to 10 to 30 mm. Yes.

In addition, coral larvae attracting method by chemical treatment of substrate surface (coral larvae growth / transformation promoting substance, application of hormone), and coral growth base by adjusting concrete components, aggregate is made of glass waste, hard Industrial waste (such as slag), shell fossils, and coal ash are known.
JP 2003-219755 A

  The method described in Japanese Patent Application Laid-Open No. 2003-219551 is intended to artificially form a high-concentration region of coral eggs and / or planula larvae. For example, a planula larva artificially obtained by aquaculture or the like is predetermined. The planulaton larvae in the net can be removed without putting the plankton net used as a sampling means out of the sea without being thrown into the area of the It has to move to the desired sea area, where the plankton net has to be assembled in an enclosure to form a high concentration area.

  Therefore, in order to form such a high concentration region, there is a problem that labor, time and equipment are required. Even if this high-concentration region is formed in a target structure or a place where corals have died, there is a possibility that a sufficient effect cannot be obtained in a state where the base environment where coral larvae settle is lost.

  In addition, if the coral larvae to be introduced contain endemic species in other sea areas, problems such as genetic disruption and lack of diversity occur.

  Further, in recent years, the number of coral larvae itself is small, and even if they join a desired sea area, there are problems such as being preyed by fish and other organisms after they have settled.

  Although it is desired to construct coral reefs by actively attracting planula larvae that inhabit the sea areas where coral reefs are to be regenerated, there has been no established method for promoting larval settlement. The method for forming irregularities on the surface of the structure described above, the method for attracting coral larvae by chemical treatment of the substrate surface, and the coral settlement base by adjusting the concrete components are still in the research stage. It has not been implemented on a large scale in the sea area.

  The object of the present invention is to eliminate the inconveniences of the above-mentioned conventional examples and to actively attract coral larvae by improving the habitat environment, without recourse to coral transplantation or transfer, and to regenerate coral reefs. To provide a coral reef creation method that can prevent glazing due to fish, etc. after settlement, and can form a coral reef without large facilities even in waters where the amount of coral larvae is small, such as depleted coral reefs It is in.

  In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that coral larvae are grown on the back side of a network structure, and the network structure is inverted to form at least a part of an underwater growth base. The gist is to install it.

  According to the first aspect of the present invention, there is a light condition as one of the factors that cause the coral larvae to settle, and light is shielded so that natural light or the like becomes a light environment of a certain value or less (within a predetermined range). Since the growth of algae that prefer a positive environment, such as green algae and brown algae, is suppressed on the surface of the base, it becomes a condition that coral larvae tend to settle. Therefore, a base that can provide this condition and promote the growth of coral larvae can be obtained by a simple and inexpensive method in which a net-like structure is laid on an underwater base such as a natural sea area. In addition, even after the coral larvae have settled on the base, the base is covered with a net-like structure, so that glazing due to fish and the like can be prevented.

  Further, coral larvae can be grown and grown on the back side of the net-like structure, so that the coral larvae can be protected from food damage such as fish and grown in a safe environment. If the network structure is turned upside down when it grows to a size that is not susceptible to damage, the coral can grow further outward from the network structure.

  As described above, the coral reef creation method of the present invention is to reinvigorate coral reefs by actively attracting coral larvae by improving the settlement environment, regardless of means such as coral transplantation and transfer. It is also possible to prevent glazing due to fish after it has settled. Furthermore, it is chemically active even in natural waters where the amount of coral larvae is small, such as depleted coral reefs (the base environment where larvae settle down is lost). Large-scale coral reefs can be created without extensive facilities for processing and transplantation.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of a coral reef creation method according to the present invention. An existing wave-dissipating block such as a tetrapod is used as a growth base 1 which is the base of the present invention, and this surface is formed into a net-like structure 2. It is covered with.

  FIG. 3 shows a second example of the above example, in which a reef / algae block is used as the growth base 1 which is the base of the present invention, and this surface is covered with a net-like structure 2. FIG. 4 shows a third example of the above example, in which a revetment is used as the landing base 1 which is the base of the present invention. In this case, if the structure material 6 for preventing scouring (for example, asphalt mat) is laid on the seabed following the revetment, and the net-like structure 2 is laid on this, the substrate 1 is spread over a wide area. Can be formed. Although illustration is abbreviate | omitted, the growth base 1 is not limited to the above artificial structures, Natural structures, such as a bedrock of a seabed, may be sufficient.

  Moreover, it is desirable to form unevenness for preventing sand settling on the surface of the settlement base 1 so that sand, mud, or the like that affects the settlement of coral larvae does not accumulate.

  In any of the examples shown in FIGS. 2 to 4, the laying of the reticulated structure 2 on the growth base 1 does not need to cover the entire growth base 1, and is intended to promote the growth of coral larvae. Only partially covered. The network structure 2 can also employ a biodegradable plastic or metal that decomposes and disappears in nature after a certain period of time.

  Coral larvae are grown and grown on the reticulated structure 2 at a location close to the growth base 1, and this is inverted and installed on the growth base 1. Only the net-like structures 2 are stacked vertically in multiple stages at intervals of 10 to 100 mm, and coral larvae are allowed to grow in this state (FIG. 1 (a)).

  Thereafter, the net-like structures 2 are arranged on the growth base 7 to grow larvae ((b) in the figure). From the beginning, the net-like structure 2 may be laid on the underwater growth base 7, and coral larvae may be grown and grown on the back side of the net-like structure 2.

  The growth base 7 is made of a white material such as coral sand or a concrete product or a material with a color close thereto, and the surface is formed on a surface where light is easily reflected. Furthermore, it is desirable to form irregularities for preventing sedimentation on the surface. In such a state, a light environment within a predetermined range is also created on the back side of the reticulated structure 2, and the coral larvae that have settled down grow between the reticulated structure 2 and the growth base 7, that is, grow. Since it grows in the direction of the base 7, it is possible to reduce the effects of food damage caused by algae-eating fish and sea urchins and to grow corals in a safe environment.

  Then, after the predetermined period, when the coral grows to a size that is not easily damaged by damage, for example, about 10 to 20 mm long, the network structure 2 is turned over, that is, the back side of the network structure 2 is turned upside down (inverted). Then, the coral that has grown is faced upward (toward the outside), and the entire network structure 2 is fixed in close contact with the growth base 1 (FIG. 1 (c)).

  As the fixing means, underwater non-separable concrete, anchors and the like can be used. In addition, in the example of 2nd Embodiment mentioned above, although multiple types of the growth base 7 and the growth base 1 were used as the base of this invention, the growth base 1 may serve as the growth base 7.

  In addition, the present invention provides a settlement base 1 according to the present invention while supplying and circulating natural seawater in a pool or a large tank installed on the land near the coast of the sea where the coral reef is to be regenerated. It is also possible to adopt a mode in which corals are grown and grown, and the base 1 is transported to the sea area to create a coral reef.

  The experimental results of observing the situation of the settlement base 1 in which the network structure 2 is laid in the actual sea area will be described. The experiment site is a subtropical sea area with a depth of about 5 m. As the network structure 2, two types of network structures A and B as shown in Table 1 below were used.

  There are two types of settlement bases: a concrete flat plate (smooth plate) with no irregularities on the surface and a concrete substrate (concavo-convex plate) with irregularities formed by fixing and exposing iron ore with an average particle diameter of 10 mm on the surface. The size was also set to 250 mm long × 250 mm wide × 50 mm thick. Nine of these two types of bases 1 were installed at the experiment site. Of the nine bases 1, three are provided with the network structure A, the other three are provided with the network structure B, and the remaining three bodies are not provided with the network structure 2; Changes were observed over the years. The net-like structure 2 (A, B) was laid on the growth substrate 1 through a gap 5 of 100 mm.

  The photosynthesis effective photon flux density (sometimes referred to as photon amount) was measured as the light intensity on the surface of the substrate 1 during the experiment. Table 2 below shows a measurement example of the photosynthetic effective photon flux density at 5 m below the sea surface. This result is an average value around noon under the clear sky in early September. It can be confirmed that the formation base 1 on which the network structure 2 (A, B) is laid is shielded from light, and that the photosynthesis effective photon flux density is reduced to about half or less of the case where the network structure 2 is not laid (natural state). It was.

  And after the predetermined period (one year) progress, the growth condition of the coral and the coral colony was investigated. Table 3 below shows the coverage of coral to the substrate 1. The coverage was obtained by photographing the surface of the substrate 1 and analyzing the image.

  Coral coral is one of the small algae belonging to the red algae plant (Rhodophyta Coralida) and grows by photosynthesis in water, but its growth is slower than that of large red algae plants. From this result, one year after the start of the experiment, the surface of the growth base 1 on which the reticulated structure 2 is not laid is dominated by algae that prefer a positive environment such as green algae and brown algae, but the regenerated structure with the reticulated structure 2 laid. In the base 1, it was found that algae that prefer a positive environment is less likely to grow due to light shielding, whereas coral can grow and its coverage increases. Moreover, when the sedimentation condition of the surface of the substrate 1 was observed, it was speculated that the uneven plate had less sand and mud accumulated than the smooth plate, and contributed to the formation of coral and coral. In the experiment, irregular irregularities were formed on the surface of the base 1 due to the exposure of the iron ore, but instead, for example, an irregular plate with regular irregularities having a groove width of 3 mm and a groove height of 4 mm was also used. A sand-preventing effect was observed.

  Coral is also an algae (lime algae) that secretes or deposits lime (calcium carbonate) on the cell wall, and 95% of the algal bodies are composed of calcium carbonate. Coral reefs are therefore one of the organisms that play an important role in the formation of coral reefs.

  In addition, it has been reported that some substances extracted from corals have the action of promoting the settlement or transformation of marine invertebrate floating larvae such as corals. It can be said that it is desirable to have an environment in which to grow. From this point of view, the laying base 1 of the present invention is shielded by the laying of the reticulated structure 2 so that algae that prefer the positive environment are less likely to grow, and the coral larvae are shielded from light in a range of light environments where corals can grow early. It can be expected to promote the establishment.

  Although the coral colony has not been confirmed by visual observation, there are still a few individuals that can be confirmed by visual observation. However, on the epiphysis base 1 laid with the reticulated structure 2, a total of seven coral colonies were observed (regardless of the presence or absence of irregularities). It was. Moreover, in the growth base | substrate 1 which does not lay the net-like structure 2, the growth of the coral colony was not seen at all. It was not clear whether the coral larvae did not grow or grow, or whether they were glazed by fish even when they were grown or grown, but the base 1 with a clearly low coral coverage is coral. It was suggested that there was a problem with the growth and growth of larvae.

  As described above, the coral reef creation method of the present invention is a simple method in which the net-like structure 2 is laid on the growth base 1 without using special chemicals or the like and without performing large-scale transplantation. The coral larvae floating in the natural world can be actively attracted to the base 1 by an inexpensive method, and the coral larvae are also attracted to the sea area where the recruitment of the coral larvae is small (the base environment where the larvae have settled is lost) Can promote life.

  By the way, according to the observation of the present inventor, it was confirmed in the above-mentioned experiment that the coral colony grew not only from the surface of the growth base 1 but also from the back side of the network structure 2 downward (in the direction of the growth base 1). It was done. As a result of investigating the back side of the net-like structure 2 laid on the settlement base 1, 0-4 individuals are found in the net-like structure A per base, and 26-30 individuals are found in the net-like structure B as well. Found each.

It is explanatory drawing which shows one Embodiment of the construction method of the coral reef of this invention. It is a perspective view of the 1st example of the growth base of the coral reef creation method of the present invention. It is a perspective view of the 2nd example of the growth base of the coral reef creation method of the present invention. It is a side view of the 3rd example of the settlement base of the coral reef creation method of the present invention.

DESCRIPTION OF SYMBOLS 1 Settling base 2 Reticulated structure 6 Structure material for scour prevention 7 Growth base

Claims (1)

  A method for creating a coral reef, characterized in that coral larvae are grown on the back side of a net-like structure, and the net-like structure is inverted and installed on at least a part of an underwater base.

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