Australian Patents Act 1990 - Regulation 3.2A Original Complete Specification, Standard Patent Invention Title: Tripod-Type Artificial Reef for a Seaweed Forest The following statement is a full description of this invention, including the best method of performing it known to the applicant: Background of the Invention 1. Field of the Invention The present invention relates generally to a tripod-type artificial reef for a seaweed 5 forest, which has a surface structure adapted to allow a variety of sea algae to be naturally and effectively embedded and implanted thereon, which is capable of reducing the volume associated with piling up pluralities of artificial reefs and thereby resulting in a considerable reduction in time and costs to be spent for the transportation and the installation thereof, which does not easily overturn or leave from its initial install position 10 at the bottom of the sea when the waves and the tidal current change, and which can highly improve the reliability of the seaweed forest and is convenient to use, by virtue of a relatively simple structure comprising supporting legs that form a substantially tripod shape on the whole; connecting plates disposed in space created by the supporting legs in such a manner that they can arrange the order of vertically-disposed and resulting in 15 extending horizontally between the supporting legs; and sea algae attaching ridges protruding upwards on the upper surface of the connecting plates, whereby the passage and the space required for providing food supply zone, spawning ground and marine habitat so as to grow various marine shellfish or fry are further effectively and intimately connected to one another with the aid of sea algae, and whereby the hiding place where sea 20 algae exist may be formed between sea algae attaching ridges. 2. Description of the Prior Art In recent years, because of various environmental factors such as an excessive inflow of various nutrients and a high temperature condition, etc., there has been a great loss of marine plants that normally live on the submarine bedrock or the bottom of an ocean in the 25 shore areas of the sea. These submarine zones are then frequently filled with large numbers of calcareous algae and thereby resulting in coral bleaching, which is the whitening of coral colonies. 1.
If various sea algae are gone due to the whitening of coral colonies, many invertebrates or large numbers of marine shellfish such as an abalone, a conch or a sea urchin and so on that prey on the sea algae or prepare a hideout in the sea algae also disappear. Because of this, there has been a great loss of spawning ground and marine habitat that normally 5 support large numbers of marine species and thereby resulting in sharp decrease in the number of useful fishery resource preying on living organisms, found principally in shallow marine waters. Recognizing this, numerous inventors have developed and disclosed devices intended to build an artificial reef in shallow marine waters having a depth of about 20 meters so as to 10 finally create seaweed forest produced by sea algae while effectively attempting to provide food supply zone, spawning ground and marine habitat required for the growth of various shellfish or fry to accomplish the generally contrary result of enhancing the accretion of particulate matter immediately adjacent to a shoreline. Many artificial reefs for providing seaweed forest have been developed and applied in 15 shallow marine waters as a marine habitat. However, most of artificial reefs developed until now have been seen to cause significant problems in the form of poor functionality and efficiency. In other words, since artificial seaweed devices according to the prior art are manufactured at a relatively simple structure such as a quadrangular-shaped structure, a 20 hemispherical-shaped structure, a hexagonal frame-type structure, a house-type structure or a stair-type structure, they often cause undesired effects such as serious decline in vitality of vast areas of such reefs due to poor embedding and implantation of sea algae and thereby resulting in poor acting in role as food supply zone, spawning ground and marine habitat required for the growth of various shellfish or fry. 25 With respect to the afore-mentioned problem, a variety of endeavors for developing artificial reefs having good functionality and efficiency have been proposed. One approach is, a rope of which germinated spores of the sea algae was artificially implanted within a water tank by land has been proposed. This rope may be wounded around a surface of the artificial reef and then the artificial reef may be installed in the bottom of an ocean in the 30 shore areas of the sea. Other approach is, an artificial reef having a large scale and a complicated structure so as to make it more suitable for obtaining natural embedding and implantation of marine alga has been proposed. Although these artificial reefs may be effective in obtaining natural embedding and implantation of marine alga, it is important to note that they suffer from inherent disadvantages which detract from their overall 2 effectiveness and desirability. That is, since the implantation or embedding process of sea algae and the manufacture and installing process of the artificial reefs would incur large costs, it is practically uneconomical to use. Since the number of germinated spores to be embedded and implanted on the rope is 5 limited, the germinated spores embedded and implanted on the rope may be undesirably grown and are difficult to put down roots on the surface of the artificial reefs. In addition, the conventional artificial reefs have the drawback that they are in danger of leading environmental pollution because of the recalcitrant rope for embedding and implanting sea algae. Namely, it must remove the rope from the artificial reefs when time passed after it is 10 used so as to prevent environmental pollution. This leads to uneconomical problem such that sea algae may be peeled off during remove of the rope. Since most of artificial reefs for providing seaweed forest may be conventionally provided in shallow marine waters having a depth of about 10-15 meters, it is likely to be overturned or broken away from their proper positions. Because of this, although artificial 15 reefs for providing seaweed forest was constructed and installed as planned, they may be overturned or broken away from their proper positions when time passed after it is used and thereby resulting in the loss of the functionality thereof. The conventional artificial reefs for providing seaweed forest may be designed with taking account of a structure required for embedding and implanting sea algae. The 20 problem is that space or the passage required for providing food supply zone, spawning ground and marine habitat so as to grow various shellfish or fry are not considered. Because of this, it is difficult to properly cultivate resources required for the growth of various shellfish or fry when relatively long time passed after artificial reefs are constructed. 25 In the case where the conventional artificial reefs for providing seaweed forest are provided on the submarine bedrock or the bottom of an ocean in the shore areas of the sea, it is difficult to safely construct them with taking account of the waves or the tidal current because of unstable geographical features of the submarine bedrock or the bottom of an ocean. Accordingly, it would have detrimental effect on free utilization of the artificial 30 reefs. Meanwhile, the artificial reefs are manufactured and assembled on the ground and then they are moved toward the submarine bedrock or the bottom of an ocean in the shore areas of the sea. At this time, it is preferred that the artificial reefs are piled up so as to cut down distribution costs by decreasing the number of times they being moved. However, in 3 the conventional artificial reefs for providing seaweed forest, the volume associated with piling up them is highly increased and it is impossible to stably pile up them without employing any additional fixing means. As a result, a long time and a substantial cost occur to transfer the artificial reefs and thereby it has poor productivity. 5 Summary of the Invention In consideration of the above-mentioned disadvantages or inconveniences of the conventional techniques, a preferred object of the present invention is to provide a tripod type artificial reef for a seaweed forest, which has a surface structure adapted to allow a 10 variety of sea algae to be naturally and effectively embedded and implanted thereon, which is capable of reducing the volume associated with piling up pluralities of artificial reefs and thereby resulting in a considerable reduction in time and costs to be spent for the transportation and the installation thereof, and which can highly improve the capability in developing the seaweed forest, by virtue of a relatively simple structure comprising 15 supporting legs that form a substantially tripod shape on the whole; connecting plates disposed in space created by the supporting legs in such a manner that they can arrange the order of vertically-disposed and resulting in extending horizontally between the supporting legs; and sea algae attaching ridges protruding upwards on the upper surface of the connecting plates, whereby the hiding place where sea algae exist may be formed between 20 sea algae attaching ridges. A further preferred object of the invention is to provide a tripod-type artificial reef for a seaweed forest, which is capable of effectively and intimately connecting the passage and the space together with the aid of sea algae, which are required for providing food supply zone, spawning ground and marine habitat so as to grow various marine shellfish or fry, 25 and whereby it is possible to accomplish seaweed forest produced by sea algae after completing construction of the artificial reef and to cultivate a variety of marine selfish or fish with the aid of the seaweed forest for a short time, which is capable of reducing the volume associated with piling up pluralities of artificial reefs and thereby resulting in a considerable reduction in time and costs to be spent for the transportation and the 30 installation thereof, which does not easily overturn or leave from its initial install position at the bottom of the sea when the waves and the tidal current change, by virtue of a relatively simple structure comprising supporting legs that form a substantially tripod shape on the whole; connecting plates disposed in space created by the supporting legs in such a manner that they can arrange the order of vertically-disposed and resulting in 4 extending horizontally between the supporting legs; and sea algae attaching ridges protruding upwards on the upper surface of the connecting plates. In order to achieve the objects, the present invention provides a tripod-type artificial reef for a seaweed forest, which is installed in the submarine bedrock or the bottom of an 5 ocean in the shore areas of the sea, characterized in that the artificial reef comprises a plurality of supporting legs, which are spaced from each other and thereby forming a substantially tripod shape on the whole; and pluralities of connecting plates, which are disposed in space created by the supporting legs in such a manner that they can arrange the order of vertically-disposed and resulting in extending horizontally between the supporting 10 legs; in which pluralities of sea algae attaching ridges respectively protrude upwards from an upper surface of the connecting plate at predetermined intervals, wherein upper ends of the supporting legs are formed as a one piece such as by forming a joint part their between, wherein both ends of the connecting plates are integrally connected with the supporting legs, whereby a hiding place where various marine shellfish or fly can live may be 15 provided by sufficient space created between the sea algae attaching ridges. Preferably, a locking edge is respectively formed at a radial inner side of a lower end of the supporting leg. Preferably, a protrusion is respectively formed on a front surface of the supporting leg. Preferably, a flow passage for allowing sea algae or fly to freely move there through is 20 formed through the supporting leg. Preferably, pluralities of sea algae attaching valleys are formed on the front surface of the supporting leg. Effect of the Invention 25 As described above, according to the present invention, it is possible to easily pile up two or three artificial reefs together and then to transfer them to a trailer or a barge in a state that they are loaded thereon with keeping their volume to a minimum. This leads to the benefit of lower number of trailers or barges required for transporting the artificial reef and lower distribution costs. 30 Although the tripod-type artificial reef according to the present invention is installed on the bottom of an ocean in the shore areas of the sea, it is possible to easily install the tripod-type artificial reef without regard to topographical features of the sea bottom and thereby facilitate convenient transport and install of the artificial reef. Also, some structures existing on the sea bottom such as the bedrock can be snugly inserted into 5 the space provided between the lower connecting plate and the supporting leg. As a result, it is possible to easily install the tripod-type artificial reef in the sea bottom and to additionally dispose some natural structures for providing food supply zone, spawning ground and marine habitat required for the growth of various marine shellfish or fry. 5 Since three supporting legs which function as an integral basic supporting frame of the artificial reef are spaced from each other with forming a substantially tripod shape on the whole, total appearance of the artificial reef including the connecting plate also has a substantially tripod shape on the whole. Due to this design feature, the tripod-type artificial reef installed on the sea bottom does not easily overturn or leave from its initial position io when the waves and the tidal current change. Although long time has passed after installing the artificial reef, the artificial reef can be kept safe by maintaining its original position. The tripod-type artificial reef according to the present invention can effectively provide food supply zone required for the growth of various shellfish or fry by allowing a 15 variety of sea algae to be embedded and implanted on the artificial reef and to grow thereon. Because the passage and the space required for providing food supply zone, spawning ground and marine habitat so as to grow various marine shellfish or fry are further effectively and intimately connected to one another with the aid of sea algae, it is possible to protect various marine selfish or fry from outside natural enemies. 20 Since narrow corner space is additionally provided on the surface of the artificial reef and the flow passage is formed through the supporting leg, sufficient space and shadow required for providing marine selfish or fry with a refuge may be provided within the artificial reef with the aid of sea algae growing up on the sea algae attaching ridges, which can perform such role of a shield for covering inner space of the artificial reef. 25 Consequently, it is possible to protect various marine selfish or fry from outside natural enemies. In view of the foregoing, it is possible to accomplish seaweed forest produced by sea algae after completing construction of the artificial reef and to cultivate a variety of marine selfish or fish with the aid of the seaweed forest for a short time. Also, it is possible 30 to restrain coastal fisheries from becoming desolated due to the whitening of coral colonies. This leads to the benefit of larger increase in the quantity of production of marine resources. That also makes it possible for establish fish farms in coast shore by using the tripod-type artificial reef according to the present invention. 6 Brief Description of the Drawings The above object and other characteristics and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings, in which: 5 FIG. I is a perspective view of a tripod-type artificial reef for providing seaweed forest according to a preferred first embodiment of the present invention; FIG. 2 is a perspective view of a tripod-type artificial reef for providing seaweed forest according to a preferred second embodiment of the present invention; FIG. 3 is a bottom perspective view of the tripod-type artificial reef for providing 1o seaweed forest as shown in FIG. 2; FIG. 4 is a fragmentary plan view of the tripod-type artificial reef for providing seaweed forest as shown in FIG. 2; FIG. 5 is a perspective view of one connecting plate, with other parts omitted for clarity; and 15 FIG. 6 is a perspective view of two tripod-type artificial reefs for providing seaweed forest according to the present invention, for showing a state that one tripod-type artificial reef is laid over another tripod-type artificial reef. Detailed Description of the Invention 20 Hereinafter, the constitution of tripod-type artificial reefs for providing seaweed forest according to preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings FIGS. I to 6. Prior to proceeding to the more detailed description of the preferred embodiment according to the present invention, it should be noted that, for the sake of clarity and 25 understanding of the invention identical components which have identical functions have been identified with identical reference numerals throughout the different views which are illustrated in each of the attached drawing Figures. Referring to FIG. 1, the tripod-type artificial reef 10 according to the preferred first embodiment of the present invention comprises three supporting legs I as an integral basic 30 supporting frame, which are spaced from each other and thereby forming a substantially tripod shape on the whole, and pluralities of connecting plates 2, which are disposed in a space created by three supporting legs I in such a manner that three connecting plates 2a,2b,2c can arrange the order of vertically-disposed and resulting in extending horizontally between two supporting legs 1. Pluralities of sea algae attaching ridges 21 7 protrude upwards from an upper surface of the connecting plate 2 at predetermined intervals. While three supporting legs 1 are shown in the drawings as a tripod shape on the whole in the preferred embodiments according to the present invention, it should be appreciate by 5 one of ordinary skill that any type of suitable design technique may be used for installing three to five supporting legs. Although the more the number of the supporting legs I is increased and then the structural strength of the artificial reef is enhanced, total area for embedding and implanting sea algae that is provided by the connecting plates 2 and the sea algae attaching ridges 21 may be relatively reduced. Accordingly, it is not preferred to 10 install more than six supporting legs 1, especially considering the manufacturing cost of the artificial reef and the functionality of seaweed forest. It is preferred to reduce the number of supporting legs I at three with receiving collateral benefits that significantly enhance the structural strength of the artificial reef and thereby resulting in a considerable reduction in time and costs to be spent for 15 manufacturing the artificial reef when compared with the conventional artificial reef. Also, it is preferred to connect upper ends of the supporting legs 1 in a one piece such as by forming a joint part 12 their between so as to increase total area for embedding and implanting sea algae that is provided by the connecting plates 2 and the sea algae attaching ridges 21, more particularly to increase the capability of creating seaweed forest by 20 obtaining sufficient space among the supporting legs 1. The joint part 12 serves as a weight supporting point for substantially supporting total weight of the artificial reef, which may be applied thereto through individual supporting legs I disposed at a tripod shape. Accordingly, it is preferred to integrally form pluralities of supporting legs I at a one piece such as by using a mould with the aid of reinforcement 25 materials such as deformed bars when pouring concrete and then curing the concreted surface so as to produce the artificial reef. It is preferred that the supporting leg I has a square pillar shape and an upper surface of the joint part 12, that is the uppermost surface of the artificial reef, may be formed as a flat surface. Due to this, it is possible to additionally obtain narrow corner 30 space for providing sea algae or fry with hiding place and a surface for embedding and implanting sea algae. While the supporting legs 1 are shown in the drawings as a square pillar shape, it should be appreciate by one of ordinary skill that they can be properly shaped such as a circular pillar shape, a trigonal pillar shape, a hexagonal pillar shape or an octagonal pillar 8 shape. It is preferred that a lower end of the supporting leg I may be formed as a sharp blade so as to allow the lower end of the supporting leg 1 to be easily embedded in the submarine bedrock or the bottom of an ocean in the shore areas of the sea where the tripod 5 type artificial reef 10 according to the present invention is installed. Referring to FIG. 2, in the tripod-type artificial reef 10 according to the preferred second embodiment of the present invention, a locking edge 13 is formed at a radial inner side of the lower end of the supporting leg 1, respectively. A protrusion 15 is formed at a middle portion or a lower portion on a front surface of the supporting leg 1, respectively. 10 When one tripod-type artificial reef 10 is laid over another tripod-type artificial reef 10, the locking edge 13 of the latter may be locked at the protrusion 15 of the former. Pluralities of sea algae attaching valleys 14 are formed on the front surface of the supporting leg 1. The most important concept in the preferred second embodiment of the present invention is that the locking edge 13 and the protrusion 15 are additionally formed on the 15 supporting leg 1, respectively so as to assist piling up pluralities of tripod-type artificial reefs 10 neatly. It should be appreciated by one of ordinary skill, that other construction exclusive of structural change to the supporting leg 1, that is other inventive elements such as the sea algae attaching valley 14, the connecting plate 2 and the sea algae attaching ridge 21, can be selectively used in accordance with an application and may vary based on 20 application. In other words, the tripod-type artificial reef 10 according to the preferred second embodiment of the present invention as described above with reference to FIG. 2 operates in the same manner as the tripod-type artificial reef 10 according to the preferred first embodiment of the present invention as described above with reference to FIG. 1, except 25 for the construction and the operation of the locking edge 13 and the sea algae attaching valley 14. Accordingly, other construction exclusive of the locking edge 13 and the sea algae attaching valley 14 can be always applied regardless of application. While the shape and the position of the locking edge 13, the sea algae attaching valley 14 and the protrusion 15 are shown in FIG. 2, it should be appreciate by one of ordinary skill that various 30 changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Other important concept in the preferred second embodiment of the present invention is that the connecting plate 2 is provided between the supporting legs 1. The connecting plate 2 comprises an upper connecting plate 2a, a middle connecting plate 2b 9 and a lower connecting plate 2c. Both ends of the connecting plates 2a,2b,2c horizontally extending between the supporting legs I are integrally connected with the supporting legs 1, respectively. Pluralities of sea algae attaching ridges 21 protrude upwards from the upper surface of the connecting plates 2a,2b,2c, respectively. 5 When three connecting plates 2a,2b,2c are disposed between the supporting legs 1 in such a manner that they can arrange the order of vertically-disposed and resulting in extending horizontally between two supporting legs 1, they may substantially cover internal space of the tripod-type artificial reef 10 as a space shield, as best seen in FIGS. 3 and 4. Due to this structure, it is possible to obtain sufficient space or passage required for 10 providing food supply zone, spawning ground and marine habitat so as to grow various shellfish or fry. When the tripod-type artificial reef 10 for producing seaweed forest is installed for the first time, various sea algae may be embedded and implanted on the sea algae attaching ridge 21 and the connecting plates 2a,2b,2c, which are spaced from each other at 15 predetermined intervals, and then they grow up at a predetermined length. As a result, space among the connecting plates 2a,2b,2c may be covered by sea algae and thereby resulting in formation of house-type hiding place where sea algae can exist in a form of walls or shields. In view of the foregoing, it is desirable to form a flow passage 11 for allowing sea 20 algae or fly to freely move there through at certain positions exclusive of the juncture between the supporting leg I and the connecting plates 2a,2b,2c. While the flow passage 11 is shown in the drawings as a rectangular shape in the preferred embodiments according to the present invention, it should be appreciate by one of ordinary skill that any type of suitable design technique may be applied for forming a desired shape such as a circular 25 shape, a triangular shape, a hexagonal shape or an octagonal shape. Also, the direction of forming the flow passage 11 can be changed such as in the forward and backward directions or in the leftward and rightward directions on the basis of application. It is preferred that the flow passage 11 is formed as a triangular-shaped passage or a rectangular-shaped passage so as to create a relatively narrow corner space in the flow 30 passage 11, where sea algae or fly can freely hide. It is further preferred that the direction of forming the flow passage 11 is set along in the leftward and rightward directions of the supporting leg 11 so as to allow sea algae to easily cover the flow passage 11. Furthermore, it is possible to provide at least two flow passages 11 at the supporting leg 11 as needed. While the connecting plate 2, which make up three layers of connecting plates 10 2a,2b,2c between the supporting legs 1, is shown in the drawings in the preferred embodiments according to the present invention, it should be appreciate by one of ordinary skill that any type of suitable design technique may be used for installing minimum two connecting plates to maximum four connecting plates 2. Although the structural strength of 5 the tripod-type artificial reef 10 can be improved by increasing numbers of the connecting plate 2, this leads to the economical waste in case where an actual area for embedding and implanting sea algae and the manufacturing cost of the tripod-type artificial reef 10 must be considered. If the number of connecting plate 2 is increased at a minimum of five, this leads to 10 the excessive overlap of the surface of the connecting plate 2 in the upward ad downward directions, with considering the state shown in FIG. 3. Because of this, the tripod-type artificial reef 10 may have the drawback that the actual area for embedding and implanting sea algae is in danger of being reduced as the surface of the connecting plate 2 is overlapped. Accordingly, when one considers the time and the cost required to 15 manufacture the tripod-type artificial reef 10 and the functionality thereof, it is uneconomical. It is preferred to integrally form the connecting plate 2 and the supporting legs 1 at a one piece such as by using a mould with the aid of reinforcement materials such as deformed bars when pouring concrete and then curing the concreted surface so as to 20 produce the artificial reef 10. It is preferred to form the connecting plate 2 as a substantially rectangular-shaped plate(shown as a trapezoidal shape in the attached drawings) so as to create a relatively narrow corner space at a position adjacent to the juncture between the connecting plate 2 and the supporting leg 1. It is preferred that the lower connecting plate 2c among the connecting plate 2 is 25 disposed at a position that is spaced from the lower end of the supporting leg 1 at a height of about 50-120cn. Because of this, although the tripod-type artificial reef 10 according to the present invention is installed onto the soft ground such as sandy soils, sandy and clay soils, or clay soils and then the lower end of the supporting leg 1 has sunk a predetermined depth, the capability of creating seaweed forest with the aid of the connecting plate 2 does 30 not deteriorate over time. As described above, an actual and effective surface structure for embedding and planting various sea algae may be provided on the tripod-type artificial reef 10 by using the sea algae attaching valley of the supporting leg 1 in combination with the sea algae attaching ridges 21 protruding upwards on the upper surface of the connecting plate 2. 11 Also, pluralities of algae attaching valleys 22 are provided on a one connecting plate 2, as shown in FIG. 5, which function as a hiding place for marine shellfish or fly preying on sea algae. It is preferred to set a gap between the sea algae attaching ridges 21 from about 5cm 5 to 10cm so that sea algae attaching valleys 22 may be properly spaced from each other where marine shellfish or fly can freely move there through and hide therein. Preferably, the thickness of the sea algae attaching ridge 21 is about 5ci that is corresponding to the width of root of kelp or sea mustard. It is further preferred to set a gap between the sea algae attaching valleys 14 of the supporting leg 1 about 5cm that is corresponding to the 10 width of root of kelp or sea mustard. More particularly, it is preferred to set a maximum width between the sea algae attaching valleys 14 from about 2cm to 4cm so that a hiding place where marine spats can freely move there through and hide therein can be provided. When the tripod-type artificial reef 10 is made as a large scale of reef, the height thereof may be about 5m. When the tripod-type artificial reef 10 is made as a middle-sized 15 reef or a small-sized reef, then the sizes thereof are about 2m-2.5m of height thereof, about 30cm of thickness of the supporting leg 1, about 50cm of width and about 20cm of thickness of the connecting plate 2, approximately 10cm of thickness and height of the sea algae attaching ridge 21. It should be appreciate by one of ordinary skill that any type of suitable design 20 technique may be used for variously changing the sizes of the tripod-type artificial reef 10 with taking account of the depth of water in coast sea and the ground state of the sea bottom, the intensity of waves or tidal current at appropriate waters where tripod-type artificial reef 10 may be installed, the kind and the ecological nature of fish resources to be grown up by using the artificial reef 10, etc. 25 Hereinafter, the operation of the tripod-type artificial reef according to the present invention will be explained in more detail with reference to the accompanying drawings. As described above, the tripod-type artificial reef 10 according to the present invention is provided with a plurality of supporting leg 1, which are spaced from each other and thereby forming a substantially tripod shape on the whole; and pluralities of 30 connecting plates 2a,2b,2c, which are disposed in a space created by three supporting legs 1 in such a manner that they can arrange the order of vertically-disposed and resulting in extending horizontally between the supporting legs 1. Due to this structure, it is possible to pile up two to three artificial reefs 10 together and then they can be transferred to a trailer 12 or a barge and be loaded thereon with keeping their volume to a minimum. In other words, more particularly in the preferred second embodiment according to the present invention, it can easily and accurately pile up pluralities of artificial reefs 10 together as shown in FIG. 6 due to the cooperative operation between the locking edge 13 5 and the protrusion 15 of the supporting leg 1. This leads to the benefit of lower number of trailers or barges required for transporting the artificial reef 10 and lower distribution costs. Although the tripod-type artificial reef 10 according to the present invention is installed on the bottom of an ocean in the shore areas of the sea, the lower end of the supporting leg 1 can easily penetrate into cracks of the bedrock or into directly the ground 10 of the bottom of an ocean and thereby resulting in safe settlement of the artificial reef 10. Consequently, it is possible to easily install the tripod-type artificial reef 10 without regard to topographical features of the sea bottom and thereby facilitate convenient transport and install of the artificial reef 10, which is comparatively safe for use in embedding and planting sea algae. 15 More particularly, as shown in FIG. 3, some structures existing on the sea bottom such as the bedrock can be snugly inserted into the space provided between the lower connecting plate 2c and the supporting leg 1. As a result, it is possible to easily install the tripod-type artificial reef 10 on the sea bottom and to additionally dispose some natural structures for providing food supply zone, spawning ground and marine habitat required 20 for the growth of various marine shellfish or fry. Since three supporting legs 1 which function as an integral basic supporting frame of the artificial reef 10 are spaced from each other with forming a substantially tripod shape on the whole, total appearance of the artificial reef 10 including the connecting plate 2 also has a substantially tripod shape on the whole. Due to this design feature, the tripod 25 type artificial reef 10 installed on the sea bottom does not easily overturn or leave from its initial position when the waves and the tidal current change. Although long time has passed after installing the artificial reef 10, the artificial reef 10 can be kept safe by maintaining its original position. If the tidal current smoothly flows through the space provided between the supporting leg 1 and the connecting plate 2, 30 various sea algae can be easily embedded and implanted on the sea algae attaching ridges 21 of the connecting plate 2 and the sea algae attaching valleys 14 formed on the surface of the supporting leg 1. As described above, the tripod-type artificial reef 10 according to the present invention can effectively provide food supply zone required for the growth of various 13 shellfish or fry by allowing a variety of sea algae to be embedded and implanted on the artificial reef 10 and to grow thereon. Since the sea algae growing up on the sea algae attaching ridges 21 can perform such role of a shield for covering inner space of the artificial reef 10, sufficient space and shadow required for providing marine selfish or fry 5 with a refuge may be provided within the artificial reef 10. Due to this, it is possible to protect various marine selfish or fry from outside natural enemies. In view of the foregoing, it is possible to accomplish seaweed forest produced by sea algae after completing construction of the artificial reef 10 and to cultivate a variety of marine selfish or fish with the aid of the seaweed forest for a short time. Also, it is possible 10 to restrain coastal fisheries from becoming desolated due to the whitening of coral colonies. This leads to the benefit of larger increase in the quantity of production of fishery resources. That also makes it possible for establish fish farms in coast shore by using the tripod-type artificial reef 10 according to the present invention. By virtue of the relatively simple structure of the tripod-type artificial reef 10 15 comprising the supporting leg 1 which forms a substantially tripod shape on the whole and thereby it may operate the same manner as a tripod, the connecting plates 2 which are disposed in a space created by the supporting legs 1 in such a manner that the connecting plates can arrange the order of vertically-disposed and resulting in extending horizontally between the supporting legs, and the sea algae attaching ridges 21 protruding upwards on 20 the upper surface of the connecting plates 2, it is possible to produce the best tripod-type artificial reef 10 which is capable of giving a considerable reduction in costs and of highly improving the reliability of the seaweed forest. Consequently, the best tripod-type artificial reef 10 according to the present invention has significant advantages over previously known artificial reefs. 25 It is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the above description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways by modifying the structure of piping in accordance with a kind of the 30 ship. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of 14 the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but 5 that the invention will include all embodiments falling within the scope of the appended claims. The term "comprise" and variants of that term such as "comprises" or "comprising" are used herein to denote the inclusion of a stated integer or integers but not to exclude any other integer or any other integers, unless in the context or usage an exclusive 10 interpretation of the term is required. Reference to prior art disclosures in this specification is not an admission that the disclosures constitute common general knowledge in Australia. 15