JPH06206804A - Man-made gathering-place for fish of sea area cleaning type and structure of man-made gathering-place for fish - Google Patents

Abstract

PURPOSE:To obtain a man-made gathering-place for fish for farming fisheries, provided with seawater cleaning function. CONSTITUTION:A hollow part 2 is made at the central part of a block made of cellular concrete formed by blending cement with iron oxide and a blowing base to give a main body 1 of a man-made gathering-place for fish. In seawater 20, structures G and H prepared by inserting iron rods 6 into the hollow parts 2 are arranged at both sides of a structure F made by packing iron particles 3 to the hollow part 2 and a direct electric source 8 is connected to each iron rod of the structures G and H. Iron ion is formed from an anode (+) and ferrous hydroxide is made from a cathode (-). Multiplication of diatoms, plankton, etc., is improved while excellently maintaining adhesion of spores of marine algae by the uneven part of the block made of gas cellular concrete, seawater is cleaned and gathering effect of fishes and shellfishes is bettered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sea area purification type fish reef or fish reef structure suitable for purification of coastal sea areas, cultivation and fisheries.

[0002]

2. Description of the Related Art In recent years, fisheries in Japan have been forced to switch from conventional fisheries caught in the open ocean to fisheries raised in the near sea by setting 200 nautical miles around the world. In such a situation, conventionally, by sinking a concrete fish reef or a steel fish reef into the sea, or by sinking a fish reef coated with an iron compound on the surface of a concrete fish reef, collecting fish,
Methods of capturing have been tried. In addition, a fish reef structure is also used in which cement is mixed with crushed stone that is commonly used as an aggregate, and molded and structured so as to have continuous voids.

[0003]

In recent years, the increase in marine pollution has been a global trend, but in Japan, where the country is surrounded by the sea and waterfront development is actively carried out, marine pollution is remarkable. . Above all, pollution is remarkable in closed sea areas such as Tokyo Bay, Osaka Bay, and the Seto Inland Sea, and the natural environment of the coastal sea area is disturbed accordingly, water pollution and pollution progress, and the type and amount of marine organisms decrease sharply. Reproduction is also at stake. As described above, in Japan where ocean pollution is severe, it is not possible to expect improvement of water quality in the ocean by the conventional method in which the proliferation of microorganisms is small and the purification action is poor. That is, the conventional concrete fish reef has a drawback that it takes a long time for the growth of seaweed and the concrete is calcareous, so that the generated seaweed easily separates from the concrete.

Further, in iron and steel fish reefs, it takes a long time to produce iron ions and is not fast-acting. Furthermore, a fish reef in which an iron compound is applied to the surface of a concrete fish reef has problems such as high application cost of the iron compound and lack of durability. In addition, in recent years, the phenomenon called Isoyaki is spreading all over Japan,
Especially, the bedrock on the Sea of Japan side of Hokkaido has coral algae (main component is CaC).
It is covered with O ₃ ) and is a barren desert area without seaweed. Therefore, even if spores such as kelp land,
It is feared that the CaCO _{3 on} the surface of the coral alga will be exfoliated, and eventually the spores will not be able to settle, so that the catch on the coast of Japan will decrease drastically in the future. An object of the present invention is to provide a novel fish reef or fish reef structure which solves the above-mentioned conventional problems and exhibits a much higher fish collecting effect than ever before.

[0005]

In order to achieve the above-mentioned object, a sea area purification type fish reef structure according to claim 1 of the present invention has a continuous void in which iron oxide and a foaming base material are mixed in cement. And a hollow portion is formed in the block, and the hollow portion has an opening opening to the surface of the fish reef body.

The sea area purification type fish reef structure according to claim 2 is the sea area purification type fish reef structure according to claim 1, wherein the hollow portion is filled with iron. Alternatively, it is a mixed metal-filled fish reef structure in which the hollow portion is filled with iron and a mixture of a metal having a higher electric potential than iron.

Further, in the sea area purification type fish reef according to claim 3, three iron-filled fish reef structures according to claim 2 are arranged side by side in the sea, and the iron-filled fish reef structure is located in the center. The DC power source is connected to each of the iron-filled fish reef structures in order to change the electric polarity with the iron-filled fish reef structures arranged on the left and right of the iron-filled fish reef structure, or the iron according to claim 2. While the filling type fish reef structure is installed in the sea, a metal having a higher electric potential than that of iron is arranged on the left and right sides of the iron filling type fish reef structure, and the metal and the iron filling type fish reef structure are The feature is that the spaces are electrically connected.

[0008]

Now, the principle and operation of the present invention will be described. Mixing iron oxide and foaming base material into cement, molding,
The interior of structured cellular concrete has continuous voids with a large surface area. Therefore, such aerated concrete is provided with (a plurality of) hollow portions at arbitrary places to form a fish reef structure, and when this is immersed in sea water, sea water freely flows in and out of the fish reef structure, A large amount of oxygen is supplied together with the inflowing seawater, so that the inside of the void can be maintained in an aerobic atmosphere. Therefore, a large amount of microorganisms inhabiting seawater adhere to and propagate on the hollow portion, the inside of the voids, and the surface of the aerated concrete to form a biofilm layer. The biofilm layer decomposes organic matter in seawater to promote mineralization, and at the same time promotes the growth of seaweeds and microorganisms, resulting in improvement of the biological environment.

It is well known that the amount of seaweed adhered to iron oxide used as an aggregate is much larger than that when ordinary crushed stone is used as an aggregate. In addition, the surface of aerated concrete has many irregularities, and a large amount of algae grows on the iron oxide surface to form a community,
Compared with aerated concrete that does not contain iron oxide, the growth of microorganisms is further promoted and the purification action in the sea area is further accelerated. Furthermore, since the inside of the cellular concrete block (fish reef body) molded and structured by mixing cement into iron oxide and a foaming base material has continuous voids with a large surface area, when immersed in seawater, bubbles will form. Seawater freely flows in and through the concrete, a large amount of oxygen is supplied together with the inflowing seawater, the aerobic atmosphere is maintained in the voids, and diatoms and plankton that have absorbed nutrient salts in the seawater are in the voids and aerated concrete. A large number of small fish, which attach to the surface and breed, and collect diatoms and plankton, gather.

It has been known that the adhesion of seaweed to the surface of iron oxide is good, and the surface of iron oxide of the aerated concrete fish reef body with many irregularities has a seaweed that has absorbed nutrient salts in seawater. A large number of species flourish into a community and gather in a community of seaweeds in which fish, including small fish, proliferate. When the hollow parts (plurality) provided in any part of the fish reef body having the above-mentioned action are filled with iron of any shape and immersed in seawater, there are parts on the iron surface with different potentials. A local battery is formed by mixing them, and a corrosion current flows out from the anode of the local battery, and iron is eluted as iron ions.

Here, the reaction at the electrode portion is expressed by the equations [1] and [2].

[Number 1] anode part: Fe → Fe ²⁺ + 2e ^-

[Equation 2] Cathode part: 1/2 · O ₂ + H ₂ O + 2e ⁻ → 2
OH ^- OH produced by the addition cathode unit in seawater ^- and the anode of Fe ²⁺
And are combined to produce ferrous hydroxide as in the formula [3].

[Equation 3] Fe ²⁺ + 2OH ⁻ → Fe (OH) ₂ ferrous hydroxide precipitates as insoluble ferric hydroxide due to the oxygen in water, as shown in [Equation 4]. Immediately after the precipitation, Fe (OH) ₃ exists in equilibrium with Fe (OH) ₂ ⁺ as in the formula [5].

[Equation 4] 2Fe (OH) ₂ + 1/2 · O ₂ + H ₂ O → 2Fe (O
H) ₃

[Equation 5]

Fe ions and Fe (OH) ₂ ⁺ generated by the above reaction are essential components for growing diatoms, plankton and seaweeds. Therefore, the Fe ions and Fe (OH) ₂ ⁺ eluted from the iron filled in the hollow part of the aerated concrete fish reef body flow out from the aerated concrete surface into the sea through the continuous voids, so that the aerated concrete surface Breeding of diatoms and plankton is promoted. Also, on the iron oxide surface of the aerated concrete reef body with many irregularities, the growth of adhering seaweed is accelerated, and as a result, small fish gather in search of food such as abundant diatoms, plankton, etc. Are gathered in large numbers near seaweeds.

Next, iron (potential in seawater: −0.6 to −0.7 V _VS SCE) and a metal having a higher potential than iron, for example, graphite (potential in seawater +0.2 to 0.3V _VS SCE), when mixed with activated carbon and soaked in seawater, current flows from graphite with high potential to iron with low potential to form a battery. Similarly, it becomes Fe ions and elutes, and graphite becomes a cathode, and OH ⁻ is generated as in the formula [2]. In the case of filling with iron and a mixture of metals having a higher potential than iron, compared with the case of filling with iron alone,
Since the amount of Fe ions eluted increases at an accelerated rate,
Plankton's reproduction and seaweed's growth are further improved, and indirectly, the collection effect is further increased as compared with the case where only iron is added. The amount of Fe ions eluted from the iron serving as the anode increases as the area of the graphite serving as the cathode increases. Therefore, the amount of Fe ions eluted can be adjusted by changing the area (that is, weight) of the graphite.

An iron-filled fish reef structure filled with iron of an arbitrary shape is immersed in the sea in (a plurality of) hollow portions provided at arbitrary locations of the fish reef body having the above-mentioned action, and the left and right sides of the structure are immersed. An iron-filled fish reef structure with the same structure as this is placed on both sides, and if a DC voltage is applied while changing the polarity of the electrodes at regular intervals by local energy such as wave power, wind power, or sunlight, A current flows out from the fish reef structure connected to the positive electrode, and the outflowing current flows into the fish reef structure located in the middle, passes through the fish reef and is connected to the negative electrode of the DC voltage. Inflow into the structure. Therefore, in the fish reef structure of the positive electrode, Fe becomes ions and elutes in seawater, as in the above-mentioned [Formula 1].

On the other hand, in the fish reef located between the positive and negative poles, when the current from the positive electrode flows in, passes through the fish reef and flows out into the seawater again, as shown in the formula [1],
Fe elutes as Fe ions. On the one hand reef structure that is connected to the negative electrode, similarly to Equation 2 formula above, OH ^-
Occurs. In seawater, OH ⁻ generated at the negative electrode
Fe ²⁺ generated at the positive electrode are combined with each other to generate Fe (OH) ₂ in the same manner as in the above [Formula 3]. Furthermore, due to the oxygen in seawater, insoluble Fe (OH) ₃ as in the above formula [4]
However, Fe (OH) ₃ immediately after the precipitation exists in equilibrium with Fe (OH) ₂ ⁺ , as in the above-mentioned [Equation 5].

Next, by switching the polarities of the fish reef structure connected to the positive electrode to the negative electrode, the fish reef structure connected to the negative electrode to the positive electrode, and the like, the reverse of the above is obtained. A current flows in the direction of, and the same reaction as described above occurs at the positive and negative polarities. Therefore, by changing the polarities of the fish reef structure at regular intervals, the F
e-ions can be eluted. By further changing the applied voltage, the concentration of eluted Fe ions can be adjusted. Next, the iron-filled fish reef structure in which iron of any shape is filled in the hollow part (plurality) provided in any part of the fish reef main body is immersed in the sea, and the potential on both sides is higher than that of iron. When a metal having an arbitrary shape, for example, graphite is placed, and both metals and the iron-filled fish reef structure are connected by a conductive wire, a current flows from the graphite having a high potential to the iron having a low potential to form a battery. It becomes an anode, and [Number 1]
As in the formula, it elutes as Fe ions, graphite becomes the cathode, and OH ⁻ is generated as in the formula [2].

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sea area purification type fish reef structure as an embodiment of the present invention will be described below with reference to the drawings. 1 (a) to 1 (d) are perspective views of the fish reef structure of the first embodiment, FIG. 2 and FIG.
FIG. 3 is a schematic perspective view of the second and third embodiments of FIG.

First, the first embodiment will be described. In Fig. 1 (a), a fish reef structure made of aerated concrete (sometimes referred to as "fish reef body" below) 1 is a mixture of iron oxide, a foaming base material, and cement and water, and has bubbles of 150 mmφ x 300 mH. It is molded as a concrete block, and after molding, a hollow part 2 of 90 mmφ × 300 mmH is provided in the center part thereof to be formed. The fish reef body thus formed was cured in air for 48 hours after molding and then cured in water (25 ° C.) for 7 days, and then used in the experiment described below. The fish reef structure in Figure 1 (b) is
The hollow portion 2 of the fish reef body 1 of FIG. 1 (a) is filled with granular iron 3 and rod-shaped reinforcing bars. In the fish reef structure of FIG. 1 (c), granular iron 3 (or rod-shaped rebar) is filled in a hollow portion 2 of the fish reef main body 1 of FIG. 1 (a) together with graphite 4 at a weight ratio of 1: 1. It is configured. Figure 1 (d)
1 shows a fish reef structure constructed by sealing a hollow part 2 of each fish reef structure shown in FIGS. 1A to 1C with a lid 5 made of concrete.

The following experiments were conducted on these fish reef structures. In the experiment, fish reef structures AE
Means a structure as shown in the following [Table 1]. The fish reef structures A to E may be abbreviated as [A], [B] ... [E] below.

[Table 1]

The test procedure is as follows. Each of the fish reef structures A to E was separately put in a 50 l poly bucket, immersed in fresh water, and water was replaced once a day to carry out alkaline cleaning of the fish reef structures for 3 days. As a result, the pH of each fish reef structure A to E after 3 days was 8.7 to 9.0. Next, instead of the above-mentioned fresh water, seawater was added and immersed for 3 days, and then the fish reef structure was pulled up and mixed with sea water for sampling, and Fe ions (Fe ²⁾ eluted from each of the fish reef structures A to E were extracted. The total concentration of ⁺ and Fe (OH) ₃ was analyzed. As a result, the Fe ion concentration was 1.4 at [A].
mg / l, 330 mg / l for [B] and [C], 85 for [D] and [E]
It was 0 mg / l. Next, after replacing the above seawater with new seawater, winding a seed thread around each fish reef structure, and then pouring seawater into the bottom of the 50 l poly bucket from the sea by a pump to overflow each fish reef structure A to E. The immersion test was performed for 3 months, and the adhesion state of diatoms adhering to the surface of each fish reef structure A to E and the inner surface of the bucket after 3 months was visually inspected.

As a result, in the case of [A] (unfilled), the diatom was slightly attached to the surface of the fish reef structure and the inner surface of the bucket. With [B] and [C] (granular and rod-shaped Fe filling), the diatom adhesion on the surface of the fish reef structure and the inner surface of the bucket was much higher than that of [A]. In addition, [C] showed more diatom adhesion than [B]. In the case of [D] and [E] (granular Fe + graphite, rod-shaped rebar + graphite), the diatom adhesion amount is further increased as compared with [B] and [C].
It could be clearly confirmed by visual observation that the diatoms proliferate remarkably when Fe ions increase. Further, when compared strongly, [E] showed more diatom adhesion than [D].

This means that in the first embodiment,
As mentioned in the preceding section of the previous [action], along with a number of irregularities in the cellular concrete is to improve the adherence of such microorganisms, ions Fe ²⁺ and ions Fe from reef structure
It indicates that (OH) ₂ ⁺ is generated, and these promote the growth of organisms attached to the surface of the fish reef structure. As the types of attached organisms, seaweeds were attached to the hollow part and the surface of bacteria, microbes and the like. From this, it is expected that aerated concrete mixed with iron oxide and having a continuous void and a hollow portion will not only purify water in the ocean but also have a remarkable effect in fresh water such as rivers and lakes. It turns out that you can.

Next, a second embodiment will be described. In FIG. 2, reference numeral 1 indicates a fish reef main body formed by mixing iron oxide, a foaming base material with cement and water, and formed as a block of aerated concrete of 150 mmφ × 300 mmH. A hollow portion 2 of 90 mmφ × 300 mmH is formed in the center thereof. And the three fish reef bodies produced in this way were cured in air for 48 hours and underwater for 7 days (25
Then, the next experiment was conducted. Reference numeral F indicates the fish reef body 1
Shows a fish reef structure formed by filling the hollow portion 2 of the fish reef with granular iron 3, and reference numerals H and G indicate a fish reef structure formed by filling the hollow portion 2 of the fish reef main body 1 with rod-shaped reinforcing bars 6. Showing the thing. In addition, the fish reef structures F, G, and H are [F],
It may be abbreviated as [G] or [H].

Then, as shown in FIG. 2, [G] and [H] are arranged on the left and right sides of [F], and a DC power source 8 is connected between both conductors 7 connected to each rebar 6 [H]. ], [G] between 0.
A DC voltage of 5V was applied. In this way, each fish reef structure F,
After arranging G and H, place this in a 260 l poly container, soak the seawater with a pump and let it soak for 3 months while overflowing, and then attach the diatom to the surface of [F], [G], and [H]. The state of adhesion was visually inspected. For reference, the fish reef body in which the hollow part was not filled with anything was immersed in the same manner as above, and the adhesion state of diatom was examined. As a result, although the hollow part was not filled with anything, diatom was slightly attached to the surface. On the other hand, a large amount of diatom was attached to the surface of the fish reef structures F to H, and it was visually confirmed that the diatom remarkably propagated due to an increase in Fe ions. Reference numeral 9 indicates the direction of current flow, and reference numerals 10a, 10b, 10c.
Are the conductors, DC power supply, and
It shows the current.

Next, a third embodiment will be described. In FIG. 3, reference numeral 11 indicates a fish reef main body, and this fish reef main body 11 was molded and cured in the same manner as in the case of the second embodiment, and then the following experiment was conducted. That is, the hollow portion 12 of the fish reef main body 11 is filled with the rod-shaped reinforcing bar 13 to form a fish reef structure J (hereinafter sometimes abbreviated as [J]),
Graphites 14 were arranged on the left and right sides of [J], and the reinforcing bar 13 and both graphites 14 were connected by a lead wire 15. Fish reef structure J and graphite 14 and 14 were placed in a 200 l poly container in this state, and the same experiment as in the case of the second embodiment was conducted. For reference, the fish reef body in which the hollow part was not filled with anything was immersed in the same manner as above, and the adhesion state of diatom was examined. As a result, although the hollow part was not filled with anything, diatom was slightly attached to the surface. On the other hand, a large amount of diatom was attached to the surface of the fish reef structure J, and it was visually confirmed that the diatom remarkably propagated due to the increase of Fe ions. The reference numeral 16 in FIG. 3 indicates the direction of current flow. The respective experimental results in the above-mentioned second and third embodiments show that the action as described in the middle stage and the latter stage of the [action] section is performed.

[0026]

As described in detail above, according to the sea area purification type fish reef and the fish reef structure of the present invention, the following effects and advantages are obtained. (1) The fish reef structure has a continuous void inside because it is made of aerated concrete that is formed and structured by mixing iron oxide with a foaming base material and cement, and at any desired location. Since the hollow part is provided, the contact area with seawater is expanded to become an aerobic atmosphere, microorganisms are easily proliferated in large amounts, and seaweed spores are easily implanted on the surface irregularities, so that organic matter The decomposition action by microorganisms is promoted,
It exerts a remarkable marine purification effect. (2) Since aerated concrete has continuous voids inside, the contact area with seawater is expanded, and the iron ions eluted from the iron in the filler promote the breeding action of diatoms and plankton, and the uneven surface Improving the implantation ability of seaweed spores, promoting a series of food chain reactions by these various effects, thereby exhibiting the gathering effect of fish and shellfish that has not been seen in the past, low cost, great durability A fish reef can be provided.

(3) By filling a hollow portion provided at an arbitrary part of the fish reef body with iron and immersing it in seawater, a portion having different potentials on the iron surface is mixed to form a local battery. The corrosion current flows out from the anode part of the local battery, and the iron ions are eluted and absorbed by the seaweed to promote the growth of the seaweed. (4) Iron (potential in seawater −0.6 to −0.7V _VS SCE) and a metal with a higher potential than iron, such as graphite (potential +0.2 to 0.3V in seawater), in the hollow part of the aerated concrete fish reef body.
_VS SCE), activated carbon, etc. are filled and soaked in seawater, a current flows from graphite with high potential to iron with low potential to form a battery, and iron becomes an anode, which is the same as (3) above. It becomes Fe ions and elutes, and graphite becomes a cathode and produces OH ⁻ . When iron and a mixture of metals having a higher potential than iron are filled, the amount of Fe ions to be eluted increases more rapidly than when only iron is filled. Therefore, diatom, plankton breeding, seaweed The growth of the species is further improved, and indirectly, the collecting effect is further enhanced as compared with the case where only iron is filled.

(5) An iron-filled fish reef structure filled with iron of an arbitrary shape is immersed in the sea in (a plurality of) hollow portions provided at arbitrary points of the fish reef body, and the By placing iron-filled fish reef structures of the same structure and applying a DC voltage while changing the polarity of the electrodes at regular intervals, a current flows out from the fish reef structure connected to the positive electrode of the DC voltage. The outflowing current flows into the fish reef structure arranged in the middle, passes through the fish reef and flows into the fish reef structure connected to the negative electrode of the DC voltage. Therefore, in the fish reef structure of the positive electrode, Fe becomes ions and elutes in seawater as in the above (3). On the other hand, in the fish reef located between the positive and negative poles, when the current from the positive electrode flows in, passes through the reef, and flows out again into the seawater, Fe becomes F
Elute as e-ion. On the other hand, in the fish reef structure connected to the negative electrode, OH ⁻ is generated as in (4) above. In seawater, OH ⁻ generated at the negative electrode and Fe ²⁺ generated at the positive electrode are further combined to generate Fe (OH) ₂ , which is converted into insoluble Fe (OH) ₃ by oxygen in seawater. However, Fe (OH) ₃ immediately after the precipitation exists in equilibrium with Fe (OH) ₂ ⁺ . Further, by switching the polarities of the fish reef structure connected to the positive electrode to the negative electrode, the fish reef structure connected to the negative electrode to the positive electrode, and the like, a current flows in the opposite direction to the above. The same reaction as described above occurs in both the positive and negative polarities. Therefore, by changing the polarity of the fish reef structure at regular intervals, it is possible to continuously
Fe ions can be eluted.

[Brief description of drawings]

FIG. 1 (a) is a perspective view of a sea area purification type fish reef structure as a first embodiment of the present invention. (b) A perspective view of a sea area purification type fish reef structure as the first embodiment. (c) A perspective view of a sea area purification type fish reef structure as the first embodiment. (d) A perspective view of a sea area purification type fish reef structure as the first embodiment.

FIG. 2 is a schematic perspective view of a sea area purification type fish reef as the second embodiment.

FIG. 3 is a schematic perspective view of a sea area purification type fish reef as the third embodiment.

[Explanation of symbols]

 1,11 Fish reef structure (fish reef main body) 2,12 Hollow part 3,13 Iron 4.14 Graphite 5 Lid 6 Rebar 7,15 Conductor 8 DC power supply

Front page continuation (72) Inventor Isamu Motomura 5-717-1, Fukahori-cho, Nagasaki-shi Nagasaki Research Institute, Mitsubishi Heavy Industries, Ltd. (72) Inventor Hironao Kasai 5-717-1, Fukahori-cho, Nagasaki-shi Mitsubishi Heavy Industries Ltd. Company Nagasaki Research Institute (72) Inventor Sada Hirabe 8 Okinoshima, Ooshima, Iojima-cho, Nishisonogi-gun, Nagasaki 2 West Nippon Tanker Service Co., Ltd. (72) Masato Yamaguchi 22-14 Ohashi-cho, Nagasaki-shi, Nagasaki In-company (72) Inventor Yumi Toyama 22-14 Ohashi-cho, Nagasaki-shi, Nagasaki Sanki Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A cement concrete block is formed by mixing iron oxide and a foaming base material into cement so as to have continuous voids. A hollow portion is formed in the block and the hollow portion is formed. A sea area purification type fish reef structure characterized by having an opening opening on the surface of the block. 2. The sea area purification type fish reef structure according to claim 1, wherein the hollow portion is filled with iron, the iron filling type fish reef structure, or the hollow portion has a higher potential than iron and iron. A mixed metal-filled fish reef structure filled with a mixture of and. 3. The iron-filled fish reef structure according to claim 2, wherein three iron-filled fish reef structures are arranged side by side in the sea, and the iron-filled fish reef structure is located in the center and the iron-filled fish reefs are arranged on the left and right sides of the iron-filled fish reef structure. A DC power source is connected to each of the iron-filled fish reef structures in order to change the electric polarity with the structure at regular intervals, or
While the iron-filled fish reef structure described in 1. is installed in the sea, a metal having a higher electric potential than iron is disposed on the left and right sides of the iron-filled fish reef structure. An ocean purification fish reef characterized by being electrically connected to a structure.