JP7619612B2 - Seaweed and shellfish farming system - Google Patents

Description

Applicable to Article 30, Paragraph 2 of the Patent Act Published on the web Journal of Aquaculture Research & Development Vol. 11 Iss. 5 No.: doi:35248/2155-9546.20.10.590 Publication date (May 30, 2020) Journal of the Seawater Society of Japan Vol. 74, pp. 249-253 Publication date (July 22, 2020) day)

The present invention relates to the cultivation of seaweed and shellfish, and in particular to a seaweed and shellfish cultivation system that allows for the simultaneous cultivation of seaweed and shellfish.

In Japan, a country surrounded by the sea on all sides, seafood is used as a daily food ingredient and the demand for seafood is high regardless of the season. Among seafood, seaweed and shellfish include luxury ingredients such as nori, abalone, and oysters, and are also in high demand as gifts.

For this reason, the seaweed and shellfish cultivation industry has become an important industry, and various improved cultivation devices have been proposed.

Conventional Ulva culture devices include those for cultivating Ulva on the ocean, in which, for example, an open-top culture device surrounded by an outer wall and having a perforated wall at the bottom that communicates with the surrounding seawater is floated on the ocean, allowing seaweed, particularly sterile Ulva, to float and flow in the gently circulating seawater within the culture device, and carbon dioxide-containing gas is ventilated from the bottom of the perforated wall (see Patent Document 1).

For example, a conventional land-based aquaculture device for seaweed, including Nori, reproduces a tidal phenomenon similar to natural tides by increasing or decreasing the water level in a culture container, while measuring the seawater temperature, amount of dissolved oxygen, and average illuminance in the seawater in the culture container to increase or decrease the amount of air sent to the seawater in the culture container, the lighting intensity, and the seawater temperature, and measuring the concentration of one or more of silicon, phosphorus, nitrogen, silicates, and ammonia salts contained in the seawater in the culture container to increase or decrease the amount of nutrients supplied to the seawater (see Patent Document 2).

In addition, there have been conventional abalone farming systems that allow diatoms, which are important for the growth of abalone shells, to flourish in the breeding seawater. For example, there is a system that includes a breeding tank, which is an aquarium tank for cultivating abalone, a solid foreign matter recovery device that separates solid matter in the breeding seawater using a cyclone, an activation device that blows chemicals, oxygen, air, etc. into the breeding seawater, an algae cultivation device that uses green algae to absorb the components in the breeding seawater through photosynthesis and cultivates them, and a microbial filtration tank that uses aerobic microorganisms to oxidize and decompose organic matter contained in the breeding seawater with nitrifying bacteria, and adds an aqueous solution of potassium silicate or sodium silicate to allow diatoms to flourish in the breeding seawater (see Patent Document 3).

Japanese Patent Application Publication No. 11-289894 JP 2005-328810 A JP 2015-89348 A

However, as in Patent Document 1, when culturing Ulva in the ocean, it is prone to contamination with food allergens such as shrimp and crabs, making it difficult to safely use the produced Ulva as food. In addition, because it is cultured in the ocean, there is the inconvenience that temperature cannot be controlled.

Land-based aquaculture devices, such as those in Patent Documents 2 and 3, are known to solve the problems of marine cultivation, but in order to artificially reproduce natural seawater conditions, it is necessary to constantly and precisely control the seawater temperature, amount of dissolved oxygen, average illuminance in the seawater, and amount of nutrients supplied inside the cultivation container, which raises the issue of increased manufacturing and maintenance costs. Also, as in Patent Document 3, some attempt to use culture fluid from an algae cultivation device for abalone cultivation, but depending on the composition of the culture fluid and the state of the dissolved components, the growth condition of the cultivated abalone can be uneven, making it difficult to cultivate abalone of high quality in a stable manner.

Furthermore, conventional aquaculture devices, such as those described in Patent Documents 1 to 3, are essentially specialized in cultivating only one type of marine product, namely seaweed or shellfish. If an aquaculture system capable of cultivating multiple types of marine products simultaneously were realized, it would be possible to achieve efficient aquaculture, but no such system is known to date.

The present invention has been made to solve the above problems, and aims to provide a seaweed and shellfish farming system that enables seaweed and shellfish to be farmed simultaneously at low cost.

The seaweed and shellfish cultivation system disclosed in this application is a seaweed and shellfish cultivation system for cultivating seaweed and cultivating shellfish, and is equipped with a seaweed cultivation tank consisting of an aquarium that contains first seawater for cultivating seaweed, a shellfish cultivation tank consisting of an aquarium that contains second seawater for cultivating shellfish, a supplying means for supplying the first seawater to the second seawater, a measuring means for measuring water quality characteristics including the amount of dissolved oxygen and temperature of the first and second seawaters, and a control means for controlling the supply by the supplying means based on the water quality characteristics measured by the measuring means so as to satisfy the cultivation conditions of the shellfish cultivated in the shellfish cultivation tank.

In this way, the seaweed culture tank is made up of a tank containing first seawater for cultivating seaweed, the shellfish culture tank is made up of a tank containing second seawater for shellfish culture, a supply means for supplying the first seawater to the second seawater, a measurement means for measuring water quality characteristics including the amount of dissolved oxygen and temperature of the first and second seawaters, and a control means for controlling the supply by the supply means based on the water quality characteristics measured by the measurement means so as to satisfy the culture conditions of the shellfish cultured in the shellfish culture tank. Therefore, the first seawater becomes an oxygen-rich culture medium in which the amount of dissolved oxygen generated by photosynthesis of the seaweed in the seaweed culture tank is supersaturated, and the culture medium is optimally controlled by the control means based on the water quality characteristics measured by the measurement means and supplied to the second seawater by the supply means. The growth of the shellfish is promoted by the oxygen-rich culture medium in the shellfish culture tank containing the second seawater, making it possible to efficiently culture seaweed and shellfish simultaneously.

In the seaweed and shellfish cultivation system disclosed in the present application, the control means decreases or increases the supply by the supply means according to the rate of change of the increase or decrease in the amount of dissolved oxygen in the second seawater stored in the shellfish cultivation tank, as necessary. In this way, the control means decreases or increases the supply by the supply means according to the rate of change of the increase or decrease in the amount of dissolved oxygen in the second seawater stored in the shellfish cultivation tank, so that the oxygen consumption due to respiration of the growing shellfish in the second seawater stored in the shellfish cultivation tank and the fluctuation in the amount of dissolved oxygen due to the oxygen supply from the seaweed culture tank are always balanced, and the growth of the shellfish can be promoted by more stably maintained dissolved oxygen.

In the seaweed and shellfish cultivation system disclosed in the present application, the control means increases or decreases the temperature of the first seawater stored in the seaweed culture tank, as necessary, depending on the rate of increase or decrease in the amount of dissolved oxygen in the second seawater stored in the shellfish cultivation tank. In this way, the control means increases or decreases the temperature of the first seawater stored in the seaweed culture tank depending on the rate of change of the increase or decrease in the amount of dissolved oxygen in the second seawater stored in the shellfish culture tank. Therefore, the inflow amount of the second seawater from the seaweed culture tank is controlled to an optimal amount of dissolved oxygen by the temperature-controlled first seawater so that the amount of carbon dioxide in the second seawater stored in the shellfish culture tank does not exceed a predetermined amount due to oxygen consumption and carbon dioxide emission by breathing of the growing shellfish. The seawater flow rate calculated by the flow rate in from the seaweed culture tank and the flow rate out from the shellfish culture tank is always optimized, and the dissolved oxygen maintained stably by the controlled seawater flow rate in the shellfish culture tank can further promote the growth of shellfish.

The seaweed and shellfish cultivation system disclosed in the present application includes a reflux means for circulating the second seawater from the shellfish cultivation tank to the seaweed cultivation tank as necessary, and the control means controls the supply by the supply means and the reflux by the reflux means based on the water quality characteristics measured by the measurement means. In this way, the seaweed and shellfish cultivation system includes a reflux means for circulating the second seawater from the shellfish cultivation tank to the seaweed cultivation tank, and the control means controls the supply by the supply means and the reflux by the reflux means based on the water quality characteristics measured by the measurement means. Therefore, the carbon dioxide-rich second seawater generated from the shellfish cultivated in the shellfish cultivation tank is refluxed to the seaweed cultivation tank by the reflux means under the control of the control means based on the water quality characteristics, and the photosynthesis of the seaweed is promoted by the carbon dioxide-rich culture solution in the seaweed cultivation tank containing the first seawater, making it possible to efficiently cultivate seaweed and shellfish simultaneously.

The seaweed and shellfish cultivation system disclosed in the present application is provided with an addition means for adding nitrifying bacteria to the second seawater returned from the shellfish cultivation tank to the seaweed cultivation tank by the reflux means, as necessary. In this way, since the system is provided with an addition means for adding nitrifying bacteria to the second seawater returned from the shellfish cultivation tank to the seaweed cultivation tank by the reflux means, the ammonia contained in the waste discharged by the cultivated shellfish in the tank containing the second seawater is detoxified into nitric acid by the oxidation action of the nitrifying bacteria, and the second seawater containing the nitric acid is returned from the shellfish cultivation tank to the first seawater in the seaweed cultivation tank by the reflux means, and the growth of the seaweed cultivated in the first seawater can be further promoted by photosynthesis performed using the nitric acid as a raw material, making it possible to efficiently cultivate seaweed and shellfish simultaneously.

In the seaweed and shellfish cultivation system disclosed in the present application, the seaweed is sterile Ulva, and the shellfish is oysters or abalone, as necessary. In this way, since the seaweed is sterile Ulva and the shellfish is oysters or abalone, the oxygen-rich culture solution produced highly efficiently by photosynthesis of the sterile Ulva creates an environment favorable for the growth of oysters or abalone, making it possible to efficiently cultivate the seaweed and shellfish at the same time, and since the sterile Ulva is rich in D-cysteinolic acid, it can also be used as an industrial raw material for D-cysteinolic acid, which is an ingredient in cosmetics and food, and seaweed that can be used for a variety of purposes can be cultivated.

In the seaweed and shellfish cultivation system disclosed in this application, the first seawater is made from deep ocean water as needed. In this way, the first seawater is made from deep ocean water, which is rich in nutrients and can also be used as a heat source. This means that the natural deep ocean water enhances the growth conditions for seaweed in terms of nutrients and temperature, making it possible to simultaneously cultivate seaweed and shellfish more efficiently and safely.

In the seaweed and shellfish cultivation system disclosed in this application, the control means controls the supply by the supply means and the circulation by the circulation means as necessary so as to maintain the dissolved oxygen content of the second seawater at 4 ppm to 20 ppm. In this way, the control means controls the supply by the supply means and the circulation by the circulation means so as to maintain the dissolved oxygen content of the second seawater at 4 ppm to 20 ppm, so that the shellfish can always grow with a necessary and sufficient amount of dissolved oxygen, which promotes the growth of the shellfish and makes it possible to simultaneously cultivate seaweed and shellfish more efficiently and safely.

FIG. 1 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a first embodiment of the present invention. FIG. 1 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a first embodiment of the present invention. FIG. 11 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a second embodiment of the present invention. FIG. 11 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a second embodiment of the present invention. FIG. 11 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a third embodiment of the present invention. FIG. 11 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a third embodiment of the present invention. FIG. 11 is a diagram showing functional blocks of a seaweed and shellfish cultivation system according to a fourth embodiment of the present invention.

First Embodiment
The seaweed and shellfish cultivation system of the first embodiment is a seaweed and shellfish cultivation system that cultivates seaweed 100 and cultivates shellfish 200, and is equipped with a seaweed culture tank 1 consisting of an aquarium containing a first seawater 11 for cultivating the seaweed 100, a shellfish cultivation tank 2 consisting of an aquarium containing a second seawater 21 for shellfish cultivation, a supply means 3 that supplies the first seawater 11 to the second seawater 21, a measurement means 4 that measures water quality characteristics including the amount of dissolved oxygen and temperature of the first and second seawaters 21, and a control means 5 that controls the supply by the supply means 3 based on the water quality characteristics measured by the measurement means 4 so as to satisfy the cultivation conditions of the shellfish 200 cultivated in the shellfish cultivation tank 2.

The seaweed 100 to be cultured in the seaweed culture tank 1 is preferably red or green algae. For example, red algae such as Porphyra yezoensis Ueda or Neopyropia yezoensis f. narawaensis are suitable, as they have a high taurine content, are highly nutritious, and can be easily cultivated and produced on land.

As the green algae of the seaweed 100, for example, seaweed of the Ulva genus can be used. For example, Ulva lactuca and/or Ulva pertusa, known as sterile Ulva, can be used. In addition, Ulva pertusa, Ulva ribbon, Ulva amiaosa, and/or Ulva minaosa, commonly known as "Aosa", can be used. In addition, Sujiaonori, Usubaaonori, Hiraaonori, Porphyra Ueda, and/or Neopyropia vezoensis f.narawaensis, commonly known as "Aonori", can be used. In addition, seaweed 100 of the Ulva genus can be used as the green algae. These green algae are excellent in nutritional value and can be easily cultivated and produced on land.

The first seawater 11 contained in the seaweed culture tank 1 is not particularly limited as long as it is seawater, but deep ocean water or mid-ocean water including deep ocean water is preferred, and deep ocean water is particularly preferred. In this way, by using deep ocean water, which is rich in nutrients and can also be used as a heat source 7b, as the raw material for the first seawater 11, the growth conditions for nutrients and temperature in the seaweed 100 are improved by the naturally occurring deep ocean water, making it possible to simultaneously cultivate seaweed and shellfish more efficiently and safely. This seaweed culture tank 1 makes it possible to culture the seaweed 100 on land.

This first seawater 11 may be seawater as is, or it may be filtered before use. Depending on the application, it is also possible to culture the seaweed 100 while aerating the first seawater 11 contained in the seaweed culture tank 1, allowing a nitrogen source and a carbon source to be supplied to the first seawater 11 more efficiently.

The second seawater 21 contained in the shellfish culture tank 2 is formed when the control means 5 supplies the first seawater 11 through the supply means 3 based on the measurement means 4. The shellfish culture tank 2 is also provided with an outlet 2a, from which the second seawater 21 stored in the shellfish culture tank 2 can be appropriately discharged, and this discharge may be by pumping or overflow.

The supply means 3 is not particularly limited as long as it is a means for transporting the solution, but for example, a pump can be used, and it may be either continuous or intermittent, and can be appropriately selected depending on the application. In addition, it is preferable that the supply period is during daylight hours, particularly from midday to early evening. Since the first seawater 11 is during daylight hours when photosynthesis of the seaweed 100 has a higher specific gravity than respiration, the first seawater 11 with a higher dissolved oxygen content is supplied to the shellfish culture tank 2, and the growth of the shellfish 200 is promoted in the presence of a high dissolved oxygen content.

In the seaweed culture tank 1, the measuring means 4 is configured as a first measuring means 41 having a first temperature measuring unit 41a for measuring the amount of dissolved oxygen in the first seawater 11 and a first temperature measuring unit 41a for measuring water quality characteristics including the temperature of the first seawater 11, and in the shellfish culture tank 2, the measuring means 42 is configured as a second measuring means 42 having a second temperature measuring unit 42a for measuring the amount of dissolved oxygen in the second seawater 21 and a second temperature measuring unit 42a for measuring water quality characteristics including the temperature of the second seawater 21. A dissolved oxygen meter and a thermometer can be used as the measuring devices, respectively.

It is particularly preferable for the control means 5 to control the amount of dissolved oxygen in the second seawater 21 to be maintained at 4 ppm (mg/L) to 20 ppm (mg/L). If the amount of dissolved oxygen is lower than 4 ppm, the growth of the shellfish 200 is likely to be inhibited due to a lack of oxygen, and if it is higher than 20 ppm, the growth of the shellfish 200 is likely to be inhibited due to an excess of oxygen. This allows the shellfish 200 to grow with a necessary and sufficient amount of dissolved oxygen at all times, promoting the growth of the shellfish 200 and making it possible to cultivate seaweed and shellfish simultaneously more efficiently and safely.

Regarding the control by the control means 5, for example, the temperature of the first seawater 11 in the seaweed culture tank 1 may be higher than the temperature of the second seawater 21 in the shellfish culture tank 2 due to the optimum growth temperature of the seaweed 100 being higher than that of the shellfish 200, and the shellfish 200 may take in (breathe) the dissolved oxygen in the second seawater 21, which may cause a change over time in the increase or decrease in the amount of dissolved oxygen in the second seawater 21 stored in the shellfish culture tank 2, but it is possible to control according to the degree of this change. From this perspective, for example, the control means 5 can decrease or increase the supply by the supply means 3 depending on the rate of change of the increase or decrease in the amount of dissolved oxygen in the second seawater 21 stored in the shellfish culture tank 2. Such supply control can be performed, for example, by controlling the flow rate by adjusting the supply and discharge (which may be pumped up or overflowed) of the second seawater 21 in the tank of the shellfish culture tank 2. As a result, in the second seawater 21 stored in the shellfish culture tank 2, the oxygen consumption due to respiration by the growing shellfish 200 and the fluctuation in the amount of dissolved oxygen due to the oxygen supply from the seaweed culture tank 1 are always balanced, making it possible to maintain a more stable level of dissolved oxygen and promote the growth of the shellfish 200.

In addition, for example, the control means 5 can decrease or increase the supply by the supply means 3 depending on the rate of increase or decrease in the amount of dissolved oxygen in the second seawater 21 stored in the shellfish culture tank 2. Such supply control can be performed, for example, by controlling the flow rate and discharge (which may be pumped up or overflow) of the second seawater 21 in the shellfish culture tank 2. As a result, the inflow of the second seawater 21 from the seaweed culture tank 1 is controlled to an optimal amount of dissolved oxygen by the temperature-controlled first seawater 11 so that the amount of carbon dioxide in the second seawater 21 stored in the shellfish culture tank 2 does not exceed a predetermined amount due to oxygen consumption and carbon dioxide emission through breathing by the growing shellfish 200, and the seawater flow rate calculated by the flow rate of inflow from the seaweed culture tank 1 in the shellfish culture tank 2 and the flow rate of discharge from the outlet 2a of the shellfish culture tank 2 is always optimized, and the dissolved oxygen maintained stably by the controlled seawater flow rate in the shellfish culture tank 2 can further promote the growth of the shellfish.

For such temperature control by the control means 5, various heat sources can be used, such as geothermal heat, deep ocean water, and/or intermediate ocean water. For example, when sterile Ulva is cultivated as the seaweed 100, the control means 5 adjusts the culture seawater temperature to a temperature range of 20 to 29°C, where the proliferation rate is high. For example, when Nori is cultivated as the seaweed 100, the temperature adjustment by the control means 5 is preferably adjusted to 18°C or lower, and more preferably controlled to 11 to 13°C. For heat exchange of such heat sources, a plate-type heat exchanger can be used, which allows heat exchange at a high heat exchange rate.

The control means 5 can control the supply amount (flow rate) of the first seawater 11 supplied from the seaweed culture tank 1 to the shellfish culture tank 2 according to the saturated dissolved oxygen amount in each of the seaweed culture tank 1 and the shellfish culture tank 2. For example, when the saturated dissolved oxygen in the first seawater 11 or the second seawater 12 is below a threshold value, the supply amount of the first seawater 11 to the shellfish culture tank 2 can be controlled to increase, thereby making it possible to maintain the dissolved oxygen amount in the shellfish culture tank 2 at a constantly high level, and promoting the growth of the shellfish 200. In particular, since the seaweed 100 can generally be grown at higher temperatures than the shellfish 200, the first seawater 11, which has a high dissolved oxygen content due to photosynthesis by the seaweed 100 at a high temperature (e.g., 30°C) in the seaweed culture tank 1, is supplied to the shellfish culture tank 2, which is controlled to a lower temperature (e.g., 20°C) than the first seawater 11. By taking advantage of the difference in the optimal growth temperatures between the seaweed 100 and the shellfish 200, the amount of dissolved oxygen in the shellfish culture tank 2 can be constantly maintained in a supersaturated state, further promoting the growth of the shellfish 200.

In addition, the control means 5, for example, controls the supply of the first seawater 11 to the shellfish culture tank 2 to be temporarily reduced when the saturated dissolved oxygen in the first seawater 11 or the second seawater 12 is equal to or higher than a threshold value, thereby making it possible to efficiently maintain the dissolved oxygen level in the shellfish culture tank 2 at a high level at all times even with a low supply from the first seawater 11, thereby promoting the growth of the shellfish 200.

In addition, for example, the dissolved oxygen control by the control means 5 can supply the first seawater 11 to the shellfish culture tank 2 when the saturated dissolved oxygen at each water temperature in the first seawater 11 reaches a concentration equal to or higher than a threshold value. For example, 70% of the saturated dissolved oxygen can be used as an index for this threshold value. It is also possible to have an output unit that issues an alarm when the dissolved oxygen concentration in the first seawater 11 reaches 70% or more of the saturated dissolved oxygen, which makes it possible to check the status of the culture solution at any time. In addition, when the saturated dissolved oxygen at each water temperature reaches a concentration equal to or lower than the threshold value, it is also possible to temporarily stop the supply to the shellfish culture tank 2 until the saturated dissolved oxygen reaches the threshold value. Such flow rate control based on the amount of dissolved oxygen by the control means 5 makes it possible to supply the first seawater 11 with a stable amount of dissolved oxygen to the shellfish culture tank 2 at all times.

In particular, when sterile Ulva is cultivated as the seaweed 100 and oysters are cultivated as the shellfish 200, this control means 5 can maximize the growth rate of the sterile Ulva by maintaining the temperature of the first seawater 11 at 25°C to 30°C. This activates the photosynthesis of the sterile Ulva in the first seawater 11, resulting in an extremely supersaturated state with a dissolved oxygen level of 10 ppm or more. For example, it is known that sterile Ulva generally grows vigorously at 30°C and also at high temperatures of 32°C, at which point the dissolved oxygen level reaches a supersaturated state of 10 ppm or more.

On the other hand, when oysters are generally cultured in such high-temperature seawater of nearly 30°C, even if air is aerated, the necessary amount of dissolved oxygen is insufficient and their growth is inhibited. However, in this embodiment, the first seawater 11, which is supersaturated even at such high temperatures, is supplied to the shellfish culture tank 2 by the supply means 3, so that seawater with an extremely high amount of dissolved oxygen is supplied to the oysters, making it possible to easily grow oysters even under the high temperatures of summer, when oysters are generally considered to have difficulty growing due to a lack of dissolved oxygen. In other words, the lack of dissolved oxygen in oysters in summer can be compensated for by seawater with supersaturated oxygen due to the culture of sterile Ulva, which is the seaweed 100. Furthermore, for the supply of this first seawater 11 under the control of the control means 5, it is more preferable to supply the first seawater 11 to the shellfish culture tank 2 after lowering the temperature to, for example, 15°C to 25°C at night, which will further increase the amount of dissolved oxygen and provide an optimal temperature for oyster growth, thereby further promoting oyster growth.

The control means 5 can also control the amount of water supplied to the shellfish culture tank 2 according to the growth rate of the shellfish 200 in the shellfish culture tank 2. For example, the optimum temperature and amount of dissolved oxygen for growth are calculated according to the growth period of the shellfish 200, which is determined by the age in months and/or total length of the shellfish 200 as the growth rate of the shellfish 200, and the flow rate of the first seawater 11 supplied to the second seawater 21 is controlled based on the respective temperatures and amounts of dissolved oxygen of the first seawater 11 and the second seawater 21 measured by the measurement means 4, so that the second seawater 21 is maintained at the temperature and amount of dissolved oxygen that are most favorable for the growth of the shellfish 200. This enables dynamic control over time, and the growth of the shellfish 200 can be efficiently promoted.

In addition to this control, it is also possible to control the flow rate of the first seawater 11 supplied to the second seawater 21 from the temperature and amount of dissolved oxygen of the first seawater 11 measured by the measuring means 4 according to the growth stage of the seaweed 100, which is determined by the age and/or total length of the seaweed 100. For example, the amount of the first seawater 11 supplied from the seaweed culture tank 1 to the shellfish culture tank 2 is varied and controlled according to the two growth stages of the seaweed 100, namely, the germination stage and the growth stage.

For example, the control means 5 controls the first seawater 11 in the seaweed culture tank 1 to maintain a relatively low temperature of 15°C to 20°C during the initial germination period of the seaweed 100, and supplies this first seawater 11 directly to the shellfish culture tank 2. The temperature of the first seawater 11 supplied to the shellfish culture tank 2 is an optimal temperature for the growth of shellfish 200 (e.g. oysters). In this way, during the germination period of the seaweed 100, the germination of the seaweed 100 is promoted and the growth of the shellfish 200 is promoted at the same time.

Furthermore, for example, during the growth period of the seaweed 100 after germination, the first seawater 11 in the seaweed culture tank 1 is controlled to maintain a relatively high temperature of 20°C to 30°C, and this first seawater 11 is supplied to the shellfish culture tank 2 when the temperature drops to, for example, 15°C to 25°C at night. The temperature of the first seawater 11 supplied to the shellfish culture tank 2 is the optimum temperature for the growth of shellfish 200 (e.g. oysters). In this way, even during the growth period of the seaweed 100, the germination of the seaweed 100 is promoted and the growth of the shellfish 200 is promoted at the same time.

This allows dynamic control over time according to the growth stage of the seaweed 100 and shellfish 200, and efficiently promotes the growth of both the seaweed and shellfish according to their growth period.

Thus, the apparatus includes a seaweed culture tank 1 consisting of an aquarium containing first seawater 11 for cultivating seaweed 100, a shellfish culture tank 2 consisting of an aquarium containing second seawater 21 for shellfish culture, a supply means 3 for supplying the first seawater 11 to the second seawater 21, a measurement means 4 for measuring water quality characteristics including the amount of dissolved oxygen and temperature of the first and second seawaters 21, and a control means 5 for controlling the supply by the supply means 3 based on the water quality characteristics measured by the measurement means 4. The seawater 11 becomes an oxygen-rich culture solution in which the amount of dissolved oxygen becomes supersaturated due to photosynthesis of the seaweed 100 in the seaweed culture tank 1, and this culture solution is optimally controlled by the control means 5 based on the water quality characteristics measured by the measurement means 4, and is supplied to the second seawater 21 by the supply means 3. In the shellfish culture tank 2 that contains the second seawater 21, the growth of the shellfish 200 is promoted by the oxygen-rich culture solution, making it possible to efficiently culture seaweed and shellfish simultaneously.

As shown in FIG. 2, the seaweed culture tank 1 may be configured in two stages, a culture tank 1a for growing seaweed and a control tank 1b for the culture solution. This allows the water quality characteristics of the seaweed culture tank 1 to be measured stably while minimizing the influence of the seaweed 100, and the accuracy of control by the control means 5 can be further improved.

Second Embodiment
The seaweed and shellfish cultivation system of the second embodiment, like the first embodiment, comprises the seaweed cultivation tank 1, the shellfish cultivation tank 2, the supply means 3, the measurement means 4, and the control means 5, and further comprises a return means 6 for returning the second seawater 21 from the shellfish cultivation tank 2 to the seaweed cultivation tank 1, as shown in Figure 3, and the control means 5 controls the supply by the supply means 3 and the return by the return means 6 based on the water quality characteristics measured by the measurement means 4.

The reflux means 6 is not particularly limited as long as it is a means for transporting the solution, but for example, a pump can be used, and it can be either a continuous or intermittent type, and can be selected appropriately depending on the application.

Under the control of the control means 5, the circulation means 6 circulates the carbon dioxide-rich second seawater 21 generated by the shellfish 200 in the shellfish culture tank 2 from the shellfish culture tank 2 to the seaweed culture tank 1, thereby promoting photosynthesis of the seaweed 100 in the seaweed culture tank 1 containing the first seawater 11 under carbon dioxide-rich conditions, further promoting the growth of the seaweed 100.

In addition, since the seaweed 100 (e.g., sterile Ulva) in the seaweed culture tank 1 can absorb ammonia contained in the feces excreted by the shellfish 200 (e.g., oysters) as a nutrient source, by circulating the second seawater 21 back to the first seawater 11, the growth of the seaweed 100 is further promoted from the standpoint of supplying a nutrient source.

The control means 5 that controls this reflux can control the reflux of the second seawater 21 from the shellfish culture tank 2 not only from the viewpoint of the amount of dissolved oxygen, but also, for example, when sterile Ulva is cultivated as the seaweed 100, so as to adjust the temperature of the culture seawater to a temperature range of 20 to 29°C, where the proliferation rate is high.

In addition, the control means 5 can control the return of the second seawater 21 from the shellfish culture tank 2 so as to adjust the culture seawater temperature to a suitable temperature of 18°C or less when cultivating, for example, Nori as the seaweed 100. This allows the temperature to be freely adjusted without the need for an external heat exchanger, simplifying the device and reducing the cost of the device.

In this way, in this embodiment, a reflux means 6 is provided for refluxing the second seawater 21 from the shellfish culture tank 2 to the seaweed culture tank 1, and the control means 5 controls the supply by the supply means 3 and the reflux by the reflux means 6 based on the water quality characteristics measured by the measurement means 4. Therefore, the carbon dioxide-rich second seawater 21 generated from the shellfish 200 cultured in the shellfish culture tank 2 is refluxed from the shellfish culture tank 2 to the seaweed culture tank 1 by the reflux means 6 under the control of the control means 5 based on the water quality characteristics. In the seaweed culture tank 1 that contains the first seawater 11, the carbon dioxide-rich culture liquid promotes photosynthesis of the seaweed 100, making it possible to efficiently culture seaweed and shellfish simultaneously.

As shown in FIG. 4, the seaweed culture tank 1 may be configured in two stages, a culture tank 1a for growing seaweed and a control tank 1b for the culture solution. This allows the water quality characteristics of the seaweed culture tank 1 to be measured stably while minimizing the influence of the seaweed 100, and the accuracy of control by the control means 5 can be further improved.

Third embodiment
The seaweed and shellfish cultivation system of the third embodiment, like the second embodiment, comprises the seaweed cultivation tank 1, the shellfish cultivation tank 2, the supply means 3, the measurement means 4, the control means 5, and the return means 6, and further comprises an addition means 7 for adding nitrifying bacteria to the second seawater 21 returned from the shellfish cultivation tank 2 to the seaweed cultivation tank 1 by the return means 6, as shown in Figure 5.

The nitrifying bacteria include nitrite bacteria (ammonia oxidizing bacteria) and nitrate bacteria. The nitrite bacteria oxidize the ammonia contained in the feces discharged from the shellfish 200 (e.g. oysters) in the shellfish culture tank 2 as follows:

[Chemical formula 1]
NH ⁴⁺ +3/2O ₂ →NO ₂ ^- +H ₂ O

Then, the following oxidation reaction occurs as nitritation by nitrate bacteria:

[Chemical formula 2]
_NO2- +1 ^/ _2O2 ^→ _NO3-

The oxidation reaction caused by this nitrifying bacteria detoxifies NH4 ⁺ and _NO2- ^, which are toxic to fish and shellfish 200 and are contained in the feces discharged from shellfish 200 (e.g. oysters) in the shellfish culture tank 2, into _NO3- ^, which is non-toxic to fish and shellfish 200. Furthermore, in the seaweed culture tank 1 where the second seawater ²¹ containing this _NO3- is returned as the first seawater 11, the seaweed 100 (e.g. sterile Ulva) absorbs this _NO3 ^- N as a nutrient source, which not only purifies the wastewater caused by the shellfish 200 (e.g. oysters) but also promotes the growth of the seaweed 100.

In this way, by providing the adding means 7 for adding nitrifying bacteria to the second seawater 21, the ammonia contained in the waste material discharged by the cultured shellfish 200 in the tank containing the second seawater 21 is chemically converted into detoxified nitric acid by the oxidizing action of the nitrifying bacteria (including nitrite bacteria and nitrate bacteria). The second seawater 21 containing this nitric acid is then returned to the first seawater 11 by the reflux means 6, and the growth of the seaweed 100 cultured in the first seawater 11 can be promoted more efficiently by photosynthesis using this nitric acid as a raw material, making it possible to efficiently culture seaweed and shellfish simultaneously.

As shown in FIG. 6, the seaweed culture tank 1 may be configured in two stages, a culture tank 1a for growing seaweed and a control tank 1b for the culture solution. This allows the water quality characteristics of the seaweed culture tank 1 to be measured stably while minimizing the influence of the seaweed 100, and the accuracy of control by the control means 5 can be further improved.

(Fourth embodiment)
The seaweed and shellfish cultivation system according to the fourth embodiment, like the third embodiment, includes the seaweed culture tank 1, the shellfish cultivation tank 2, the supplying means 3, the measuring means 4, the control means 5, and the refluxing means 6, and further includes, as shown in FIG. 7, a filtered seawater supplying unit 7a that filters seawater and supplies it to cultured seawater (first seawater 11), an Ulva recovery unit that recovers sterile Ulva as the seaweed 100 grown by cultivation, a cosmetic and food raw material supplying unit 7e that supplies the sterile Ulva as a raw material for cosmetics and/or foods, and a cosmetic and food raw material supplying unit 7f that supplies the sterile Ulva as a raw material for cosmetics and/or foods for the cultivation of abalone and/or sea urchins. The seaweed culture tank 1 further comprises a seaweed 100 land culture section for cultivating the seaweed 100 on land, which includes a nitrogen source supply section 7c (N supply section) that supplies a nitrogen source that serves as a nutrient for the seaweed 100 to the culture seawater (first seawater 11), a nitrogen concentration measurement section 41c (N concentration measurement section) that measures the nitrogen concentration in the culture seawater (first seawater 11), an air supply section 7d that supplies carbon dioxide gas to the culture seawater (first seawater 11), and a heat source 7b that supplies thermal energy consisting of geothermal heat and/or deep ocean water (including intermediate ocean water).

The supply means 3 is also composed of a culture seawater recovery and supply unit 31. The measurement means 4 is composed of a temperature measurement unit that measures the temperature of the culture seawater (first seawater 11), and a dissolved oxygen measurement unit that measures the amount of dissolved oxygen in the culture seawater (first seawater 11). The control means 5 is composed of a dissolved oxygen measurement result saturation calculation unit 5a that calculates the saturation from the measurement result of the amount of dissolved oxygen obtained, a dissolved oxygen measurement result saturation calculation result transmission unit 5a that transmits and displays the obtained calculation result of dissolved oxygen saturation on a monitor, and a temperature control unit 5c that controls the temperature of the culture seawater (first seawater 11).

The shellfish culture tank 2 is composed of an oyster culture section for cultivating oysters. The supply means 3 is composed of a culture seawater recovery and supply section 31 for recovering and supplying the culture seawater (first seawater 11) from the seaweed culture tank 1 to the oyster culture section.

In the aquaculture system according to this embodiment, seawater is supplied to the sterile Ulva culture section via the seawater filtration section 1c, and the sterile Ulva is cultured on land using this filtered water while aerating with the air supply section. The nitrogen source supply section 7c (N supply section) can supply inorganic nitrogen sources (such as NO3 _- N) and organic nitrogen sources (such as a filtrate of a hot water extract of compost) to the culture seawater (first seawater 11) in the Ulva land culture section.

At this time, the nitrogen concentration (N concentration) is measured by the nitrogen concentration measuring unit 41c (N concentration measuring unit), and the cultivation is carried out while controlling the concentration at 0.3 to 1.5 ppm. If the nitrogen concentration (N concentration) exceeds 2 ppm, other algae such as diatoms tend to grow, which can lead to contamination. If nori is used as the seaweed 100, it is preferable to carry out the cultivation while controlling the concentration at 0.3 to 0.8 ppm. If the nitrogen concentration (N concentration) exceeds 1 ppm, other algae such as diatoms tend to grow, which can also lead to contamination.

In addition, from the perspective of increasing the production efficiency of D-cysteinolic acid, an active ingredient in Ulva, it is preferable to cultivate Ulva at a high nitrogen concentration of 0.5 to 1.5 ppm. In particular, at a high nitrogen concentration of 0.8 to 1.5 ppm, Ulva's growth rate increases and the nitrogen content tends to increase (0.3 to 0.5%). On the other hand, at 0.3 ppmN, Ulva's growth rate also decreases and the nitrogen content also tends to decrease (around 0.2%).

Therefore, by supplying the dissolved oxygen-rich seawater used for culturing Ulva to oysters under high nitrogen concentration conditions of 0.8 to 1.5 ppm, oxygen-rich seawater can be produced and supplied efficiently, and growth can be promoted under conditions where both Ulva proliferation rate and Ulva concentration are high.

As the seaweed 100 (e.g., sterile Ulva or Nori) grows through cultivation, oxygen is generated from photosynthesis. The oxygen is measured by the first dissolved oxygen measuring unit 41b and calculated by the dissolved oxygen measurement result saturation calculation unit 5a based on the data from the first temperature measuring unit 41a. When the oxygen saturation at the measurement temperature reaches 70% or more, an alarm is sent from the dissolved oxygen saturation calculation result sending unit 5b, and the seawater is supplied from the culture seawater recovery and supply unit 31 to the oyster cultivation unit that requires dissolved oxygen. When supplying this seawater, the amount of seawater supplied is controlled by the control means 5 in the oyster cultivation unit based on the dissolved oxygen measured by the second dissolved oxygen measuring unit 42b and the temperature measured by the second temperature measuring unit 42a.

The inventors also confirmed that the dissolved oxygen concentration in the afternoon was 8 mg/L in the culture medium of Ulva cultivated in seawater at 20°C, and was as high as 8 mg/L in the culture medium of Nori cultivated in seawater at 15°C.

When the dissolved oxygen level is as low as 2-3 mg/L (about 1/3 of saturation), it is said to have a serious impact on oyster growth; however, by simply supplying oxygen-rich seawater obtained by cultivating such seaweed 100 (such as Ulva or Nori) to the culture liquid for shellfish 200 (such as oysters), the amount of dissolved oxygen can be increased without using special equipment such as a jet device, making it possible to steadily grow shellfish 200.

As mentioned above, examples of the heat source 7b whose temperature is controlled by the temperature control unit 5c include geothermal heat and deep ocean water (including intermediate ocean water). When culturing seaweed 100 such as Ulva, the culture seawater temperature is constantly adjusted to a temperature range of 20 to 29°C, which has a high growth rate. When culturing seaweed 100 other than Ulva, such as Nori, a temperature of 18°C or less is suitable, and preferably 11 to 13°C. A plate-type heat exchanger with high heat exchange rate is used for heat exchange with the heat source 7b.

Furthermore, of the 100 seaweeds to be cultured, it is preferable to use Ulva lactuca or Ulva pertusa, which have been confirmed to contain 0.3% or more of D-cysteinol acid per dry weight, as the seaweed to be cultured, and it is preferable to use Susabinara or Wasusabinoori, which contain 1% or more of taurine per dry weight, as the laver to be cultured.

By supplying the cultured Ulva to the cosmetics and food raw material supply unit 7e, the D-cysteinol acid and taurine contained in the seaweed 100 can be used as active ingredients in cosmetics and food raw materials, making it possible to use it for a wide range of applications.

This cosmetics and food raw material supply section 7e is composed of equipment for washing, dehydrating, and drying seaweed, and quickly washes and dries seaweed and nori, which are prone to decay, to process them into cosmetics and food raw materials. It is possible to supply the collected seaweed and nori raw, unwashed, to the abalone and sea urchin cultivation section 8 as feed. The seawater return section 61 also returns seawater from the abalone and sea urchin cultivation section 8 to the seaweed land culture section (seaweed culture tank 1). This supplies seawater rich in carbon dioxide to the seaweed land culture section (seaweed culture tank 1), further promoting the photosynthesis of the seaweed.

In this way, in this embodiment, by selecting Ulva lactuca and/or Ulva pertusa as the sterile seaweed containing D-cysteinol acid and Porphyra narawasabinori as the seaweed containing taurine, it is possible to provide a system for simultaneously producing seaweed and shellfish, in which seaweed and seaweed produced by cultivating under aeration at a controlled temperature can be supplied as ingredients for cosmetics and foods, or as feed for abalone and sea urchins, and oxygen-rich seawater produced by cultivating seaweed 100 such as sterile seaweed can be supplied to shellfish 200 such as oysters.

The following examples are provided as specific examples for explaining the present invention, but they are merely examples and the present invention is not limited to these examples.

(Example)
We confirmed whether the oxygen demand required for oyster cultivation can be met by the oxygen generated by the photosynthesis of Ulva, based on calculations using the relationship between photosynthesis and biomass production rate.

The following assumptions were used:
Ulva production (growth) rate/day: 10g/ ^m2 = 1mg/ ^cm2 (Condition 1)
Culture area (surface area): 10,000cm ² (= 100cm x 100cm) (condition 2)
Per day: 1 mg/ ^cm2 × 10,000 ^cm2 = 10,000 mg = 10 g of Ulva is produced, and at the same time, 10.6 g of _O2 is produced, and all of this 10.6 g of _O2 dissolves.

According to the literature (https://www.jstage.jst.go.jp/article/suisan/71/5/71_5_762/_pdf/-char/ja), the oxygen requirement of an oyster is 5 mg- ₀₂ /h x 24 h = 120 _mg02 /day = 0.12 _g02 /day per individual oyster with a fresh weight of 60 g (dry weight of 10 g) (photosynthesis: _6C02 + _12H2O + light energy → _C6H12O6 (180g ₎ + _6H2O + _6O2 (192g)), and it was confirmed that an oyster with a fresh weight of 60 g consumes oxygen at a rate _of 0.12 _g02 /day. From this, it was determined that 10.6 _g /day ÷ 0.12 _g /day = 88 oysters could be provided.

In addition, according to the literature (https://www.jfa.maff.go.jp/j/kenkyu/pdf/pdf/3-3.pdf), oyster growth is seriously affected at DO (dissolved oxygen) of 2-3mg/L (about 1/3 of saturation), so if half the saturated DO of 9mg/L could be maintained, 88 oysters x 2 = 176 oysters could be cultivated.

In addition, if the dissolved oxygen content of 1 ton of seawater in the oyster culture solution drops to 2 ppm, 0.5 tonnes of seawater with a dissolved oxygen content of 2 ppm can be drained out from the 1 ton, and 0.5 tonnes of seawater with a dissolved oxygen content of 6 ppm from the seaweed culture solution added (3 g of oxygen added), making it possible to maintain the dissolved oxygen content in the oyster culture tank at 4 ppm, which is suitable for growth. This allows the seaweed culture solution (oxygen-rich seawater) to be supplied to the oyster culture tank by the evening when photosynthesis ends. As a result, it is now possible to supply the seaweed culture solution to the oyster culture tank when the dissolved oxygen content in the solution is at its maximum.

The results showed that a farming system linking oyster farming and seaweed cultivation was mathematically feasible, making it possible to build a system on a scale of 1 ^m2 of seaweed cultivation area and a 0.53 t oyster farming tank.

1. Seaweed culture tank (Land-based Ulva culture section)
1a Seaweed cultivation tank 1b Culture liquid control tank 1c Seawater filtration section 11 First seawater 2 Shellfish cultivation tank (oyster cultivation section)
2a Outlet 21 Second seawater 3 Supply means 31 Culture seawater recovery/supply section 4 Measurement means 41 First measurement means 41a First temperature measurement section 41b First dissolved oxygen measurement section 41c Nitrogen concentration measurement section 42 Second measurement means 42a Second temperature measurement section 42b Second dissolved oxygen measurement section 5 Control means 5a Dissolved oxygen measurement result saturation calculation section 5b Dissolved oxygen saturation calculation result transmission section 6 Circulation means 61 Seawater return section 7 Addition means 7a Filtered seawater supply section 7b Heat source 7c Nitrogen source supply section 7d Air supply section 7e Cosmetics/food raw material supply section 8 Abalone/sea urchin cultivation section 100 Seaweed 200 Shellfish

Claims (8)

A seaweed and shellfish farming system for cultivating seaweed of the Ulva species and cultivating shellfish,
A seaweed culture tank comprising a tank containing first seawater composed of supersaturated dissolved oxygen generated by culturing the seaweed under aeration under sunlight conditions allowing photosynthesis;
a shellfish culture tank comprising a tank containing a second seawater for shellfish culture;
A supply means for supplying the first seawater to the shellfish culture tank;
a measuring means for measuring water quality characteristics including the amount of dissolved oxygen and the temperature of the first and second seawater;
a control means for controlling the supply by the supply means to the shellfish culture tank during daylight hours, while maintaining the first seawater at a relatively high temperature of 20°C to 30°C using a heat source during the growth period of the seaweed, and supplying the first seawater to the shellfish culture tank by the supply means when the first seawater used for the growth is cooled from the relatively high temperature of 20°C to 30°C maintained using the heat source to 15°C to 25°C at night, based on the water quality characteristics measured by the measurement means and the growth stage of the seaweed determined by the age of the moon and /or total length; and
Equipped with
A seaweed and shellfish farming system characterized by producing the seaweed according to its growth stage, and supplying the seaweed to the shellfish farming tank during daylight hours during the germination period and during nighttime hours during the growth period in accordance with the difference in growth temperature between the germination period and the growth period, thereby optimally maintaining the growth of both the seaweed and the shellfish. In the seaweed and shellfish farming system according to claim 1,
A seaweed and shellfish cultivation system, characterized in that the control means reduces or increases the supply by the supply means depending on the rate of change of the increase or decrease in the amount of dissolved oxygen in the second seawater stored in the shellfish cultivation tank. In the seaweed and shellfish farming system according to claim 1 or 2,
A seaweed and shellfish cultivation system, characterized in that the control means increases or decreases the temperature of the first seawater stored in the seaweed culture tank in accordance with the rate of change of the increase or decrease in the amount of dissolved oxygen in the second seawater stored in the shellfish cultivation tank. In the seaweed and shellfish farming system according to any one of claims 1 to 3,
A reflux means for refluxing the second seawater from the shellfish culture tank to the seaweed culture tank,
A seaweed and shellfish cultivation system characterized in that the control means controls the supply by the supply means and the circulation by the circulation means based on the water quality characteristics measured by the measurement means. The seaweed and shellfish farming system according to claim 4,
An addition means for adding nitrifying bacteria to the second seawater returned from the shellfish culture tank to the seaweed culture tank by the return means;
A seaweed and shellfish farming system comprising: In the seaweed and shellfish farming system according to any one of claims 1 to 5,
The seaweed is sterile Ulva or Nori,
The seaweed and shellfish farming system, wherein the shellfish are oysters or abalone. In the seaweed and shellfish farming system according to any one of claims 1 to 6,
The seaweed and shellfish culture system, wherein the first seawater is made from deep ocean water. In the seaweed and shellfish farming system according to any one of claims 1 to 7,
The control means controls the supply by the supply means and the circulation by the circulation means so as to maintain the dissolved oxygen content of the second seawater at 4 ppm to 20 ppm.

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