Aquaculture method

Abstract

To provide an aquaculture method in which the feed does not decay and no environmental stress is placed on aquaculture subjects such as fish, shellfish, crustaceans, and seaweeds.SOLUTION: Among "sodium-chloride springs", a weak saline spring having a sodium chloride content of 5 g / kg or less is used. Further, artificial seawater (in the form of powdered artificial seawater base) is added to the weak saline spring, so that the salinity of the aquaculture water is adjusted to be equivalent to the salinity of the natural habitat of aquaculture subjects such as fish, shellfish, crustaceans or seaweeds. In addition, by using a box-shaped nursery bed, restrictions on the cultivation of sea grapes are eliminated, and even more favorable results are obtained. In addition, the aquaculture subjects are not swept away by the water current.SELECTED DRAWING: Figure 3C

Description

[Technical field]

[0001] The present invention relates to an aquaculture method using a mixture of seawater (artificial seawater) and hot spring water as aquaculture water. [Background technology]

[0002] Patent Document 1 describes the rearing, storage, or transportation of immature tuna in rearing water with a salinity of 15 psu to 30 psu. Here, the salinity of seawater is said to be 3.4 to 3.5%, and is sometimes expressed in psu (practical salinity unit) converted from electrical conductivity.

[0003] Patent Document 2 describes the use of water heated by solar heat, hot spring heat, wastewater heat from a power plant, or incineration heat from an incineration plant as culture water.

[0004] Non-Patent Document 1 describes cultivating tiger pufferfish in a pool filled with hot spring water (chloride spring). This Non-Patent Document 1 describes that as a result of cultivating tiger pufferfish using (1) artificial seawater with a salinity of 0.9%, (2) artificial seawater with a salinity of 3.5%, and (3) hot spring water with a salinity of 0.9%, the growth of the tiger pufferfish was significantly faster when artificial seawater with a salinity of 0.9% and hot spring water with a salinity of 0.9% were used. Furthermore, Non-Patent Document 1 describes that tiger pufferfish cultured in hot spring water with a salinity of 0.9% are placed in water with a salinity of 3.5% 12 hours before shipping. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-005818 A [Patent Document 2] Utility Model Registration No. 3239889 [Non-patent literature]

[0006] [Non-Patent Document 1] Mizkan Water Culture Center's Newsletter "Water Culture" No. 49 Changing Aquaculture DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0007] Patent Document 1 discloses that tuna are cultivated in breeding water (artificial seawater) with a salinity of 15 psu to 30 psu. Meanwhile, in the case of aquaculture, tuna are fed to hasten their growth. When the breeding water is circulated and used, there is a problem that decay progresses even if garbage and excess feed are removed. In other words, seawater with a normal salinity cannot exhibit the effect of preventing decay.

[0008] In Patent Document 2, hot spring water is not used as the culture water, but the temperature of the hot spring is simply used to increase the temperature of the culture water, and the components contained in the hot spring water are not used for culture.

[0009] In Non-Patent Document 1, hot spring water is used alone as culture water. An example of hot spring water with a salinity of 0.9% is given, but the salinity of hot spring water, which contains salt, is different from that of seawater, and the salinity is also different, so the fish and seaweed to be cultured cannot adjust to the osmotic pressure, and in many cases they cannot grow.

[0010] Non-Patent Document 1 describes that when cultured at a salt concentration of 0.9%, osmotic pressure adjustment is not possible, which causes the amino acids stored in the liver to flow from the blood to muscle tissue, where they become umami components. However, there are very few individuals that can withstand culture at a salt concentration of 0.9%, making it unviable as a culture industry. [Means for solving the problem]

[0011] In order to solve the above problems, the aquaculture method according to the present invention was developed based on the discovery that certain hot spring water contains a component that is effective in preventing spoilage of aquaculture feed. That is, the present invention uses a weak saline spring with a sodium chloride content of 5g / kg or less among "sodium chloride springs," and further adds artificial seawater (powdered artificial seawater base) to the weak saline spring to make the salinity of the culture water equivalent to the chloride concentration of the growth environment of the cultured fish, shellfish, shrimp, crabs, or seaweed. Here, "equivalent" means plus or minus 10% of the chloride concentration of the optimal growth environment for the cultured fish, shellfish, shrimp, crabs, or seaweed. If the chloride concentration of the growth environment of the cultured fish, shellfish, shrimp, crabs, or seaweed is included, it is 1.0% to 3.5% by mass.

[0012] In addition to sodium ions, the weak salt spring used contains metasilicic acid, which is not found in seawater or is found in small amounts at most, and it is thought that this acts to prevent putrefaction.

[0013] The components of the artificial seawater base used were 58.5% by mass of chloride ions, 31.8% by mass of sodium ions, 4% by mass of magnesium ions, and 3% by mass of sulfide ions. Effect of the Invention

[0014] According to the present invention, the fish, shellfish, shrimp, crabs or seaweed to be cultured are not subjected to environmental salinity stress, and feed in the circulating culture water does not spoil.

[0015] In addition, according to the present invention, since the culture water used is a weak saline spring, the location is not limited to being close to the coast, and culture can be carried out in the mountains or in cities as long as weak saline spring water is easily available. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a front view of an apparatus for carrying out the aquaculture method according to the present invention; [Diagram 2] FIG. 1 is an overall side view of an apparatus for carrying out the aquaculture method according to the present invention. [Figure 3A] Photographs showing the state of sea grapes (Cucurbita lentillifera) cultivated in culture water with different chloride concentrations. [Figure 3B]Photographs showing the state of sea grapes (Cucurbita lentillifera) cultivated in culture water with different chloride concentrations. [Figure 3C] Photographs showing the state of sea grapes (Cucurbita lentillifera) cultivated in culture water with different chloride concentrations. [Figure 4] (A) is a photograph of the sheet-type seedbed when it is spread out, and (B) is a photograph of the sheet-type seedbed when it is closed. [Figure 5A] Photo of the lower member of the box-shaped seedbed [Figure 5B] A photo of the box-shaped seedbed in its closed state [Figure 5C] Photographs showing the growth status DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The figure shows an example of an aquaculture device installed indoors with a relatively low ceiling. A support rack 2 is fixed to the indoor floor 1, a water tank 4 is installed on the middle level 3 of the support rack 2, and an aquaculture water circulation unit 5 is placed on the floor below the middle level 3. This aquaculture water circulation unit 5 is composed of a filtration unit that filters the aquaculture water after it has passed through a foreign matter removal unit, as well as a heater, cooler, germicidal lamp, water pump, etc.

[0018] The depth of the tank 4 is set to 20cm to 50cm to facilitate work and to allow the light from the lamp to reach the bottom. A single net (seedling bed) 6 with sea grape seedlings sandwiched between it is placed inside the tank 4, and two to four seedlings sandwiched between the net 6 are placed on top of it. An air outlet 7 is attached to the water supply port of the tank 4 and below its wall, causing the bubbles that are ejected to rise along the side, generating an upward water current that is pulled by the bubbles and circulates from the bottom to the water surface inside the tank, supplying nutrients and fresh seawater to the sea grapes and helping the seedlings grow. The circulation of hot spring components prevents sea lettuce and moss from adhering to the net 6 and the inner walls of the tank.

[0019] A plant growth lamp (LED) 9 is attached to the upper bar 8 of the support rack 2. The plant growth lamp 9 is installed approximately 50 cm above the water surface of the aquarium 4. The plant growth lamp 9 consists of a support rod 10 and a lamp body 11 that is attached to the support rod 10 via a joint so that the angle can be adjusted, and the angle of the main light irradiated from the lamp body 11 is set at an angle (45° or less) to the water surface.

[0020] In the illustrated example, the number of plant growth lamps 9 is four, but one or two may be used depending on the size of the aquarium. In the case of one lamp, it should be located on either the left or right side of the center of the aquarium 4. When installed in this position, it is preferable to provide a light shield in the center of the lamp body 11 to prevent strong light from being irradiated directly below the lamp 9.

[0021] In order to provide uniform illumination over the entire water tank 4, the lamp body 11 installed in the center of the upper part can be configured to rotate slowly around the joint part.

[0022] The aquarium 4 is surrounded by a shield 12 such as a curtain. By blocking light from outside, a planned and stable illuminance can be obtained from the lighting inside the aquarium. By installing a light-reflecting plate-like object such as aluminum on the side of the aquarium, the inner surface (side of the aquarium) of this shield 12 becomes a reflective surface, so that the light from the plant growth lamp 9 is reflected toward the aquarium 4. With this configuration, the entire aquarium can be uniformly illuminated even if the distance between the water surface and the plant growth lamp 9 is small, at 50 cm or less.

[0023] In the above process, the culture water in the tank 4 is filtered and foreign matter is removed in the circulation section 5. The filtered culture water has hot spring water or artificial seawater added to it as needed, and solid food is added to the filtered water to dissolve it, or water-soluble food is added and the temperature is adjusted before it is sent to the tank.

[0024] Figure 3 shows the results of cultivating using different culturing waters: (A) shows the state after 10 days when cultivated using a strong chloride saline spring (8.5 g / kg sodium chloride), (B) shows a weak chloride saline spring (0.9 g / kg sodium chloride), and (C) shows a state after cultivating using a weak chloride saline spring + artificial seawater (chloride concentration 3.4%).

[0025] As can be seen from Figures 3(A) to (C), when culture water (A) and (B) were used, the growth of sea grapes was poorer than that of (C). In particular, when the chloride concentration was low, as shown in (B), the sea grapes dissolved before shipping, significantly reducing their commercial value.

[0026] In addition to sea grapes, the inventor also conducted experiments on saltwater fish (small horse mackerel) and freshwater fish (rainbow trout and yamame salmon) by changing the culture water to a weak chloride salt spring + artificial seawater, and varying the chloride concentration from 1.0 to 3.5%.

[0027] Small horse mackerel We made hot spring seawater with a salinity of 3.2% by dissolving artificial seawater into the hot spring water and setting the water temperature to 25 degrees, and used this as the circulating water for the tank shown in Figure 1. We then placed four small horse mackerel caught in a fixed net into the tank. Immediately after being placed in the tank, the small horse mackerel became accustomed to the hot spring seawater and swam calmly without any violence. When the water temperature rose, frozen ice packs were added to cool it down and maintain the water temperature. When seawater is used, the fish and its skin will usually change color and peel off, lose their slime, and their condition will deteriorate, but when hot spring seawater is used, the water quality has deteriorated even after 24 hours, but the horse mackerel remains alive and does not struggle. This suggests that the ingredients in the hot spring have sterilizing and protective effects.

[0028] Rainbow trout and yamame trout The circulating water in the tank was hot spring seawater with a salinity of 3.4% and a temperature of 18°C, prepared by dissolving artificial seawater in hot spring water. Swimming rainbow trout and yamame salmon were scooped up with a net, placed on a mat, and the fish was held down by hand. A needle was inserted through the base of the gills to cut the spinal nerve and stop the fish from moving. (Needle disposal) A plastic sieve was floated in the hot spring seawater, and the rainbow trout and yamame trout that had been treated with the hooks were placed in it and allowed to rest. The body temperature of a fish is the same as that of water, 18°C, and the body temperature of a person holding a fish is 36.5°C, so it is said that touching a fish directly with your hands would normally cause the fish to get burned and injured. In normal seawater, the skin of the fish's body would become damaged, peel off, and the slime covering the surface of the body would come off. However, the rainbow trout and yamame trout placed in hot spring seawater had no problems with their skin, the slime had not come off, and they were in good condition, moving their gills, breathing, and remaining calm. Because the salinity was 3.4%, the rainbow trout died in about a day and the yamame trout died in a day and a half. This is thought to be caused by the salinity, and it is believed that the problem can be solved by lowering the salinity. In addition, by combining needle treatment with hot spring seawater, a synergistic effect is achieved that reduces injury and sterilizes the fish if it is injured.

[0029] As a result of the above, the chloride concentration at which the organisms can grow varies depending on the type of organism being cultured. In general, the chloride concentration at which organisms can grow, including those living in brackish waters, is ±10% of the chloride concentration in the optimal growing environment.

[0030] Figure 4 shows a sheet-shaped seedbed (net) 6. Sea grapes are set as culture subjects on the seedbed (net) 6 in the open state as shown in (A), and then closed. Cultivation in this state prevents the culture subjects from moving due to water currents. However, there is a risk that the culture subjects will be pinched and restrained from above and below, hindering their growth.

[0031] Therefore, the present inventors carried out aquaculture using a box-shaped seedbed 6 shown in FIG. 5, instead of a sheet-shaped seedbed. As a result, as shown in FIG. 5(B), a box-shaped nursery bed 6 was filled with sea grapes and cultivated. As a result, the sea grapes grew so much that the boundaries between adjacent nursery beds became indistinguishable, as shown in FIG. 5(C).

[0032] By using a box-shaped nursery like this, the sea grapes were no longer restricted in their growth, and more favorable results were obtained. In addition, the cultivated specimens were not washed away by water currents. [Industrial Applicability]

[0033] The aquaculture method of the present invention has a high degree of freedom in terms of the place where it can be carried out, and aquaculture can be carried out not only in a greenhouse dedicated to aquaculture, but also inside a building, etc. [Explanation of symbols]

[0034] 1...floor, 2...support rack, 3...middle level of support rack, 4...aquarium, 5...aquaculture circulation section, 6...net (seedbed), 7...air outlet, 8...upper bar of support rack, 9...plant growth lamp (LED), 10...support rod, 11...lamp body, 12...shield.

Claims

1. This method of aquaculture involves circulating culture water in aquaculture tanks while adding feed to the culture water, characterized in that the culture water is made by adding artificial seawater (powdered artificial seawater base) to a weak salt spring having a sodium chloride content of 5 g / kg or less, thereby increasing the chloride concentration until it becomes equivalent to the salinity of the growth environment of the fish, shellfish, shrimp, crabs, or seaweed to be cultured.

2. The culture method according to claim 1, wherein the culture object is sea grapes, and the chloride concentration of the culture water is 3.0 to 3.5 mass%.

3. 2. The culture method according to claim 1, wherein the culture object is seaweed, and a box-shaped net is used as a seedbed.

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