Cultivation method for culturing object and cultivation management system for culturing object

Abstract

To provide a cultivation method for a culturing object capable of appropriately maintaining a cultivation environment of the culturing object in a fish preserve or a water tank.SOLUTION: A cultivation method for a culturing object observes the behavior of a culturing object in a fish preserve or a water tank over time using an acoustic wave device and manages the cultivation environment of the culturing object.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for cultivating aquaculture objects, in which the dynamics of the aquaculture objects in water are observed using an acoustic device, and a system for cultivating and managing the aquaculture objects. [Background technology]

[0002] Patent Document 1 discloses a method for calculating the size of aquatic organisms in a fish pen from images of the aquatic organisms in the pen taken with a camera or sonar. Patent Document 2 discloses a feeding method for an aquaculture pen in which an underwater camera is used to calculate the amount of image change caused by the movement of the aquatic organisms inside, and the feeding activity of the cultured fish is evaluated based on the amount of image change to control a feeder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-21477 [Patent Document 2] Japanese Patent Publication No. 2023-1108 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a method for cultivating aquaculture objects and a system for cultivating and managing aquaculture objects, which are capable of maintaining an appropriate environment for cultivating the objects in a cage or tank. [Means for solving the problem]

[0005] The present invention provides the following: [1] A method for cultivating aquaculture targets, comprising observing the dynamics of the targets in a fish pen or tank over time using an ultrasonic device and managing the environment for cultivating the targets. [2] The method according to [1], wherein the acoustic device is an imaging sonar. [3] The method described in [2], which includes quantifying the behavior of individuals from the difference in images from the imaging sonar. [4] The method according to any one of [1] to [3], further comprising taking photographs of the inside of the fish preserve or aquarium tank over time using an underwater camera. [5] The method according to any one of [1] to [4], which comprises measuring at least one of the average swimming speed, swimming speed distribution, average body weight, and body weight distribution of the cultured object. [6] The method according to any one of [1] to [4], which comprises measuring the average swimming depth or swimming depth distribution of the cultured object. [7] The method according to any one of [2] to [4], which comprises measuring the frequency of abnormal swimming of the cultured subject. [8] An ultrasonic device that outputs ultrasonic waves into a fish cage or tank and detects the reflected waves of the ultrasonic waves to obtain data on the distribution and / or swimming status of the cultured objects in the fish cage or tank; and a calculation unit that calculates at least one of the average swimming speed, average body weight, average swimming depth, frequency of abnormal swimming, swimming depth distribution, and swimming speed distribution of the cultured target based on the data on the distribution state and / or swimming state; A system for managing the cultivation of aquaculture objects, comprising: [Effects of the Invention]

[0006] According to the present invention, by understanding the dynamics of the cultured object in the cage or tank, it is possible to maintain an appropriate culture environment. [Brief explanation of the drawings]

[0007] [Figure 1] This is an example of an imaging sonar image when an imaging sonar is attached to the top of a yellowtail fish pen. (A) is a schematic diagram showing the installation of the imaging sonar on the pen and its detection method. (B) is image data that actually detects the shadows of yellowtail fish inside the pen. [Figure 2] These are images showing the principle of PIV in a yellowtail aquaculture pen. (A) is a diagram showing the positions of grid points in the imaging sonar and the correlation coefficient map. (B) is an enlarged view of the correlation coefficient map in (A). [Figure 3] 1 is a block diagram of an example of the overall configuration of a system according to the present invention. [Figure 4] 1 is a graph showing the average fish weights of farmed yellowtail in the male, female, and mixed groups as of late May. [Figure 5] This is a box plot showing the depth distribution of yellowtail schools in the male, female, and mixed areas. A represents the male area, B represents the female area, and C represents the mixed area. The vertical axis represents the height of the yellowtail from the bottom of the cage, and the horizontal axis represents the time of observation. [Figure 6] Box plots showing the speed distribution of yellowtail schools in the male, female, and mixed groups. A represents the male group, B the female group, and C the mixed group. The vertical axis represents the swimming speed of the yellowtail, and the horizontal axis represents the time of observation. DETAILED DESCRIPTION OF THE INVENTION

[0008] 1. Cultivation method of the aquaculture target A first embodiment of the present invention is a method for cultivating aquaculture targets, which includes using an ultrasonic device to observe the dynamics of the aquaculture targets in a cage or tank over time and managing the culture environment for the aquaculture targets. The method of this embodiment makes it possible to appropriately grasp and manage the condition of the aquaculture targets even in situations where visibility is difficult, such as in large-scale cages or sink-and-float cages, where the size and depth of the culture environment make it difficult to visually observe the condition of the aquaculture targets inside, where water transparency is reduced (e.g., in a cage or tank where chlorella or other substances have been administered, or where a large amount of food remains), or where light intensity is low at times such as dusk or night. Furthermore, it is possible to manage the condition of the aquaculture targets more accurately and efficiently than by visual inspection.

[0009] As used herein, the term "cultivated object" refers to fish and shellfish that have been fed and raised under controlled breeding conditions in a fish preserve, tank, etc. before shipping, regardless of the length of the period. Fish and shellfish to be cultivated include, but are not limited to, fish of the genus Seriola (yellowtail, yellowtail, amberjack, amberjack, etc.), genus Tuna, red sea bream, sea bass, tiger puffer, flounder, carp, kuruma prawn, spiny lobster, abalone, turban shell, and octopus.

[0010] As used herein, "fish preserve" refers to a structure that separates a natural aquatic environment such as the sea, river, or lake using netting, poles, sheets, fiberglass reinforced plastic (FRP), plastics, etc., in order to house and cultivate the target fish and shellfish for cultivation. As used herein, "aquarium" refers to a container or structure installed on land that contains water and is a device or facility for cultivating aquatic organisms. As used herein, the target fish and shellfish for cultivation are cultivated in a fish preserve or aquarium (land-based aquaculture).

[0011] As used herein, "managing the rearing environment" refers to maintaining or improving at least one of the parameters, such as rearing density, water temperature, and depth, to a state suitable for rearing during the rearing of aquaculture targets. For example, if the water temperature is suitable for rearing, this state is maintained, and if the water temperature is high, it means lowering the water temperature.

[0012] In this specification, the term "ultrasonic device" refers to a device also known as a "sonar" or "sound detector" that detects all underwater objects by emitting sound waves into the water and detecting the waves reflected off the object. The sound waves generated by the ultrasonic device are not particularly limited as long as they can be used to detect underwater objects, but are preferably ultrasonic, i.e., sound waves of 20 kHz or higher that are inaudible to the human ear. The installation location of the ultrasonic device is not particularly limited as long as it can detect underwater aquaculture targets, but can be, for example, above a fish pen or above an aquarium.

[0013] As used herein, "imaging sonar" refers to a device that scans underwater with sound waves, preferably ultrasonic waves, and captures images. While conventional sonars periodically emit a single ultrasonic wave, imaging sonars simultaneously emit tens to hundreds of sound waves in a planar pattern at a frequency of several Hz to several hundred Hz, allowing for planar scanning of the water, thereby making it possible to grasp not only the distribution of the cultured objects within the pattern, but also the speed and direction of movement of each individual. For example, an Oculus M (Blueprint Subsea) can be used as an imaging sonar.

[0014] In the method of this embodiment, it is preferable to use an imaging sonar, as this allows for more detailed analysis of the dynamics of the cultured fish. Figure 1 shows an example of an imaging sonar image captured when an imaging sonar is attached to the top of a yellowtail pen. Figure 1A is a schematic diagram showing the installation and detection mode of an imaging sonar 11 in a pen 12. Figure 1B shows image data of an actual yellowtail fish shadow. In the illustrated example, the imaging sonar 11 is installed at a single location at the top of a yellowtail pen 12, and 512 2.1 MHz ultrasonic waves are emitted from the imaging sonar 11 to form a fan-shaped plane, with the images updated at a frequency of 15 Hz to capture images of individual yellowtail 13 in the pen. In practice, the images can be captured as two-dimensional video, enabling analysis of the dynamics of the individual yellowtail, specifically, their distribution and swimming patterns.

[0015] A single imaging sonar may be fixed and installed to capture video of a single plane perpendicular to the water surface. Alternatively, multiple imaging sonars may be installed to enable three-dimensional analysis of the inside of the fish pen or aquarium. Alternatively, the imaging sonar may be subjected to movements such as translation on the water surface and rotation on its axis to enable three-dimensional analysis of the inside of the fish pen or aquarium.

[0016] By analyzing images obtained by imaging sonar, it is possible to observe the behavior of each individual fish in the fish pen. Specifically, a method can be used to quantify the behavior of individuals based on the temporal difference in imaging sonar images. One such method is particle image velocimetry (PIV). PIV involves mixing particles that follow the flow of a fluid into a flow field, determining the particle's displacement vector dx over a very short time dt from visualized images captured continuously over time, and estimating the velocity vector dx / dt. PIV is broadly divided into two types: image correlation (PIV in the narrow sense) and particle tracking velocimetry (PTV). However, in this specification, unless otherwise specified, we refer to PIV in the narrow sense.

[0017] The method of this embodiment may include observation with an underwater camera in addition to the observation with the sonar. While observation with a sonar, particularly an imaging sonar, is useful for understanding the overall condition of a fish pen or aquarium, an underwater camera can obtain a more detailed understanding of the condition of some individuals. An underwater camera is particularly useful in a water environment with little turbidity.

[0018] The method of this embodiment preferably uses an ultrasonic device to measure at least one of the following parameters for the aquaculture target in the cage or tank: -Average swimming speed; - average weight; -Average swimming depth; -Frequency of abnormal swimming; -Swimming depth distribution; -Swimming position (horizontal position) distribution; -Swimming speed distribution.

[0019] The method for measuring the average swimming speed of the cultured object is not particularly limited, and any known sonar measurement method may be used. For example, imaging sonar, more specifically, particle image velocimetry (PIV), can be used for measurement. Figure 2 shows an image of a yellowtail culture pen demonstrating the principle of PIV. Figure 2A shows the positions of lattice points in the imaging sonar. Figure 2B is an enlarged view of one correlation coefficient map 22 surrounded by four lattice points in Figure 2A. The velocity vector (dx / dt) can be calculated from the position change per unit time (dt) of an individual within the correlation coefficient map 22 at a specified lattice point 21 in the image. The average swimming speed can be obtained from values ​​calculated from multiple correlation coefficient maps within the detection area, preferably all correlation coefficient maps in which individuals can be detected. The spacing between the lattice points 21 is preferably between 1 / 3 and 1.5 times the average body length of the target individuals.

[0020] The weight of the cultured subject can be determined by measuring the individual size, specifically one or more of the individual's body length, total length, body height, and body width, using an ultrasonic device, preferably an imaging sonar, and then using a correspondence table prepared in advance for each individual type. The average weight can be obtained by calculating the average weight of multiple individuals, preferably 50 or more individuals, more preferably 100 or more individuals.

[0021] The average swimming depth of the cultured object is not particularly limited and may be determined by any known measurement method using an ultrasonic device. For example, it can be obtained by measuring the depth of each individual detected in an image taken by the ultrasonic device and calculating the average value.

[0022] The frequency of abnormal swimming behavior in farmed fish can be measured by analyzing the swimming direction of each individual using imaging sonar. For example, when farmed fish are migratory fish such as yellowtail, schools of fish typically move in the same direction within the same environment. However, as described above, imaging sonar can calculate not only the velocity vector (dx / dt), i.e., speed, but also the direction of movement, making it possible to detect individuals moving in a direction different from their normal direction of movement.

[0023] The distribution of swimming speed and swimming depth of the cultured object can be analyzed by measuring the swimming speed and swimming depth as described above, and then creating a distribution curve of the measured swimming speed and swimming depth, rather than calculating the average value.

[0024] The method of this embodiment will be described below in detail for each aspect. The aspects described below are merely examples, and are not intended to limit the method of this embodiment to the following aspects.

[0025] <First aspect: Rearing density management> The first aspect relates to the management of rearing density. More specifically, the first aspect is a method that includes a step of measuring the average swimming speed and / or average body weight of the cultured subjects in a cage or tank using an acoustic device, preferably an imaging sonar, and adjusting the number of individuals to be reared per unit volume in the cage or tank (rearing density) based on the average swimming speed and / or average body weight. This method can reduce the risk of collisions between individuals, contact with nets or tank walls, and poor growth due to limited movement in the cultured subjects.

[0026] For example, in the case of the genus Seriola, lowering the rearing density according to the average swimming speed of fish species with faster average swimming speeds (e.g., yellowtail is faster than amberjack) will improve the rearing coefficient and reduce the risk of fish disease compared to fish species with slower average swimming speeds. Also, if the average swimming speed changes depending on the season and water temperature, the rearing density can be optimized according to the average swimming speed.

[0027] As the aquaculture target grows, it is necessary to transfer the fish from aquariums to cages or to divide one cage into multiple cages for further nutrition. This embodiment is useful for determining the timing of transfers and nutrition. The appropriate rearing density in a cage or tank can be calculated for each individual species from the average swimming speed and average body weight. The appropriate rearing density can be calculated using a correspondence table or calculation formula previously determined for each individual species. Alternatively, the average swimming speed and average body weight, rearing density, and corresponding individual collision and injury frequency can be calculated using artificial intelligence or the like that has learned the training data.

[0028] <Second mode: Depth control of floating / sinking cages> The second aspect relates to depth management of a sink-and-float pen. More specifically, the second aspect relates to a method for adjusting the submerged depth of a sink-and-float pen by measuring the average swimming depth of the cultured subjects within the pen using an acoustic device, preferably an imaging sonar. Many aquatic organisms, particularly fish, have different optimal water temperatures depending on their species, and tend to migrate horizontally or vertically toward their optimal temperature zone. For example, they inhabit deeper waters in summer as the water temperature rises and shallower waters in winter. The depth of a sink-and-float pen can be adjusted to suit the ecology of the cultured subjects. In summer, water temperature rises near the water surface, so the pen can be moved to a deeper position. While the timing and degree of movement of a sink-and-float pen can be calculated based on empirical data on season and water temperature, this aspect allows for more accurate depth management by measuring the actual swimming depth of the cultured subjects over time and adjusting the pen to reflect these changes.

[0029] <Third aspect: Measures against diseases and parasite damage> The third aspect relates to the management of cultured fish for the treatment and / or prevention of disease and parasitic damage. More specifically, the third aspect is a method for determining the necessity and timing of medicating a cultured fish by measuring the frequency of abnormal swimming behavior of the cultured fish using imaging sonar. For example, fish of the genus Seriola, particularly amberjack, are known to be affected by skin worms, a parasitic worm that attaches to the body surface. Individuals infested with skin worms are often observed to exhibit characteristic behaviors such as rubbing their bodies against the netting on the bottom or sides of the fish pen. By measuring the frequency of individuals exhibiting such abnormal swimming behaviors, the frequency of individuals affected by disease or parasites can be determined.

[0030] It is preferable to set thresholds in advance for the velocity vectors based on the normal swimming patterns of the cultured objects and the velocity vectors based on the abnormal swimming patterns. The thresholds are preferably calculated for each cultured object and for each disease or parasite damage. Such thresholds may be calculated using artificial intelligence or the like that has learned known data on the velocity vectors of the normal swimming patterns and abnormal swimming patterns of each cultured object as training data.

[0031] <Fourth aspect: Seed selection> The fourth aspect is seed selection. More specifically, the fourth aspect is a method for predicting the quality of growth and feed efficiency of seed, for example, fry of fish, when starting to raise them, by analyzing the swimming depth distribution and swimming speed distribution.

[0032] <Fifth aspect: Reproductive period management> The fifth aspect is the management of reproductive periods. More specifically, the fifth aspect is a method for predicting the reproductive period from the swimming depth and swimming speed of a cultured object, particularly fish, and managing shipping times, etc. For example, yellowtail migrate to upper layers during the reproductive period, decrease their swimming speed, and then move to lower layers after the reproductive period. Yellowtail typically lose weight during and immediately after the reproductive period, making them unsuitable for shipping. By measuring the average swimming depth and average swimming speed, it is possible to determine when a fish is unsuitable for shipping without dissecting the individual and observing its gonads, etc. The reproductive period varies depending on the cultured object, and even for the same species, it varies depending on the rearing environment, fish size, and age. This aspect makes it possible to more accurately predict the appropriate shipping time.

[0033] <Sixth mode: Feeding management> The sixth aspect relates to feeding management. More specifically, the sixth aspect relates to a method for managing the timing, rate, etc. of feeding cultured subjects using an ultrasonic device. When feeding cultured subjects, particularly fish, incorrect timing or amount can result in excess feed in the cage or tank, worsening water quality, or in an increase in thin individuals due to low feed intake. In this aspect, by knowing in advance the distribution and / or swimming state of the cultured subjects before and after feeding, the timing, rate, etc. of feeding can be managed in real time based on the results of the distribution and / or swimming state of the cultured subjects in the cage or tank measured by an ultrasonic device, preferably an imaging sonar. For example, if it is known in advance that there is a certain tendency for the cultured fish to swim deeper or slower as they approach satiation, it is possible to grasp in real time whether they are satiety during feeding, and if so, to immediately reduce the amount or speed of feed, or stop feeding, thereby reducing excess feed. Reducing excess feed not only reduces feeding costs, but also has the effect of preventing deterioration of water quality in the fish pen or aquarium.

[0034] <Other aspects> The method of this embodiment can also be used in all situations requiring dynamic observation of aquaculture targets, such as detecting the presence or absence of abnormal swimming behavior to detect the intrusion of small fish into the netting of the fish cage (to prevent predatory behavior and death due to collision with the netting), and observing changes in water temperature and dissolved oxygen content.

[0035] 2. Aquaculture management system A second embodiment of the present invention is a system for cultivating and managing cultured objects. The system of this embodiment is characterized by comprising: an acoustic device that outputs acoustic waves into a cage or tank and detects reflected waves of the acoustic waves to acquire data on the distribution and / or swimming conditions of the cultured objects in the cage or tank; and a calculation unit that calculates at least one of the average swimming speed, average body weight, average swimming depth, frequency of abnormal swimming, swimming depth distribution, and swimming speed distribution of the cultured objects based on the distribution and / or swimming condition data. In this embodiment, the definitions of terms, purpose of use, aspects, etc. are the same as those in the first embodiment unless otherwise specified or unless otherwise contradictory.

[0036] FIG. 3 shows a block diagram of the overall configuration of an example of the system of this embodiment. An acoustic device 32 (preferably an imaging sonar) is installed in a fish pen 31, and data on the distribution and / or swimming behavior of the cultured fish within the pen is acquired. Examples of the distribution data include the depth distribution and speed distribution of the population. Examples of the swimming behavior data include the swimming speed and speed vector of each individual fish. The acquired data is sent to a calculation unit 33. In the illustrated example, the calculation unit 33 includes a processor 34, a main memory 35, an auxiliary memory 36, a communication interface 37 (hereinafter, the interface will also be referred to as "I / F"), and an input / output I / F 38. The processor 34 is a central processing unit that controls the operation of each unit of the calculation unit 33. The processor 34 is, for example, a central processing unit (CPU), a graphics processing unit (GPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or the like. The processor 34 deploys programs stored in the auxiliary storage unit 36 ​​in an executable manner in a working area of ​​the main storage unit 35. The main storage unit 35 stores programs executed by the processor 34, data processed by the processor 34, etc. The main storage unit 35 is a flash memory, a random access memory (RAM), a read-only memory (ROM), etc. The auxiliary storage unit 36 ​​stores various programs such as an operating system (OS) and various data. The auxiliary storage unit 36 ​​is, for example, a solid state drive (SSD), a hard disk drive (HDD), or a combination thereof. The communication I / F 37 is a device for connecting the computing unit to a network such as a LAN, for example, a network interface controller (NIC), etc. The input / output I / F 38 is a device controller for inputting and outputting data to and from input / output devices such as a mouse, keyboard, and display connected to the computing unit.

[0037] The communication I / F 37 of the calculation unit 33 is connected to the ultrasonic device 32 so as to be able to communicate with it via wired or wireless communication. The communication I / F 37 receives data relating to the distribution and swimming state of the culture targets in the fish pen 31 from the ultrasonic device 32. The processor 34 then processes the data and displays the distribution of the culture targets in the fish pen 31 on the display unit 39. In the illustrated example, the calculation unit 33 and the display unit 39 are shown as separate devices, but the calculation unit 33 may be integrated with the display unit 39.

[0038] The calculation unit 33 can calculate at least one of the following parameters for the culture target in the fish cage based on the data received from the sonic device 32: -Average swimming speed; - average weight; -Average swimming depth; -Frequency of abnormal swimming; -Swimming depth distribution; -Swimming position (horizontal position) distribution; -Swimming speed distribution.

[0039] The calculation unit 33 may further indicate a specific management action indicator based on at least one of the parameters. For example, the calculation unit 33 may calculate an appropriate rearing density for the cultured target from the average swimming speed and / or average body weight. Alternatively, the calculation unit 33 may calculate an appropriate depth for a sink-and-float cage from the average swimming depth. Alternatively, the need for treatment such as medicinal bathing may be determined based on the frequency of abnormal swimming. Alternatively, the growth status may be predicted based on the swimming speed distribution and swimming depth distribution of the seedlings. The derivation of management actions based on such parameters may be performed using artificial intelligence (AI). When using AI, a trained model can be constructed through machine learning using a known neural network using a database containing data on each parameter and the derived management action as training data. Using this, appropriate management actions can be derived from parameter values ​​obtained from a group of cultured targets for which management actions are unknown. The database can be stored, for example, in the auxiliary storage unit 36. The derivation can be performed, for example, by the processor 34, and the results can be displayed, for example, on the display unit 39. [Example]

[0040] <Example 1: Investigation of growth status of sex-segregated yellowtail aquaculture> (1) Raising artificially hatched Mojako On January 18, first-generation artificially hatched yellowtail (12 females and 8 males) were artificially inseminated to obtain fertilized eggs. After confirming hatching on January 20, the fish were placed in land-based tanks for rearing. From February 28 to March 5, they were released into the ocean and continued rearing in the fish pens. On June 9, the fish were measured. The average fish weight was 74.4 g. On July 11, they were vaccinated and measured. The average fish weight was 176.7 g. Each fish was then tagged for individual identification and sexed. On August 9, the fish were divided into 250 males (male group), 250 females (female group), and 259 mixed-sex groups (mixed group) and placed in separate pens for further rearing. The pens for each group were spaced at least 30 m apart. The distance between each cage was set so that the yellowtail raised in each cage could not recognize each other directly by sight or indirectly by secreting sex hormones. For example, the separation distance was set to approximately three times the length and width of the cage, but this is not limited to this. The size of each cage was 4m long x 4m wide x 4m deep, and from the 15th month of sea surface rearing onwards, it was set to 8m long x 8m wide x 8m deep. The water temperature in the cages was 15.2-31.0°C. Formulated feed was used.

[0041] (2) Rearing and fish weight measurement After measuring the fish body weight in each cage on July 11, the yellowtail were reared for approximately 10 months until May of the following year. Figure 4 shows the fish weight in each area as of late May. Fish weight was measured by randomly sampling 50 fish from each test area. Fish weight was high in all cages where males and females were reared separately, with the female area showing particularly high fish weight. On the other hand, fish weight in the mixed area was lower than in the female and male areas, with no difference between males and females being observed.

[0042] (3) Measurement of distribution and swimming behavior using imaging sonar The yellowtail in each pen were raised for another two months. In mid-July, an imaging sonar (OCULUS M, Blueprint Subsea) was installed in each pen to measure the distribution and swimming behavior of the yellowtail within the pen. The imaging sonar settings were as follows: Number of beams / frequency: 512 / 40Hz Horizontal angle: 130 degrees Maximum range: 10m Range resolution: 2.5mm Measurements were conducted for 14 hours from 5pm to 7am the next day in the male and female areas, and for 14 hours from 6pm to 8am the next day in the mixed area, with data collected every hour.

[0043] Figure 5 shows the depth distribution of yellowtail schools in each area. Figure 5A shows the male area, Figure 5B shows the female area, and Figure 5C shows the mixed area. The vertical axis represents height from the bottom, and the horizontal axis represents time. Figure 6 shows the speed distribution of yellowtail schools in each area. Figure 6A shows the male area, Figure 6B shows the female area, and Figure 6C shows the mixed area. The vertical axis represents individual speed, and the horizontal axis represents time. The depth distribution of yellowtail schools was significantly wider in the mixed area. Although the speed distribution did not show as significant differences as the depth distribution, it was shown to become faster in the mixed area, especially from evening to night. From the above, it is inferred that yellowtail individuals in the mixed area were significantly more active than those in the male and female areas, which resulted in more energy consumption and less energy used for growth, which was reflected in the differences in fish weight. The above results suggest that the growth conditions of yellowtail in the fish pens can be predicted by observing their distribution and swimming behavior using imaging sonar, and that the growth environment can be managed to improve growth conditions.

Claims

1. A method for cultivating aquaculture targets, comprising observing the behavior of the aquaculture targets in a fish pen or tank over time using an ultrasonic device, and managing the cultivation environment for the aquaculture targets.

2. The method of claim 1 , wherein the acoustic device is an imaging sonar.

3. The method of claim 2 , further comprising quantifying the behavior of the individual from the difference in the images obtained by the imaging sonar.

4. The method of claim 1 further comprising photographing the inside of the fish pen or tank over time with an underwater camera.

5. 10. The method of claim 1, comprising measuring at least one of the average swimming speed, swimming speed distribution, average body weight, and body weight distribution of the cultivated object.

6. 10. The method of claim 1, comprising measuring the mean swimming depth or swimming depth distribution of the aquaculture object.

7. The method of claim 2, further comprising measuring the frequency of abnormal swimming in the cultured subject.

8. An ultrasonic device that outputs ultrasonic waves into a fish cage or aquarium and detects reflected waves of the ultrasonic waves to obtain data on the distribution and / or swimming state of the cultured objects in the fish cage or aquarium; and a calculation unit that calculates at least one of the average swimming speed, average body weight, average swimming depth, frequency of abnormal swimming, swimming depth distribution, and swimming speed distribution of the cultured target based on the data on the distribution state and / or swimming state; A system for managing the cultivation of aquaculture objects, comprising:

Images