Aquaculture fish activity detection device, activity detection method, and feeding control device

Abstract

To provide an activity detection device and an activity detection method for cultured fishes, and a feeding control apparatus, capable of correctly grasping an activity state of each layer of cultured fishes, for properly adjusting a feeding amount according to an activity state to feeding to cultured fishes, to individual crawls, even when various conditions in crawls are different, such as a size, a depth, a shape, and kinds of the cultured fishes of the crawls.SOLUTION: A feeding control device 10 including an activity detection device of cultured fishes comprises: four activity detection sensors 20 one of which is arranged on a front layer L1 of a crawl C in which the cultured fishes are cultured, and the respective residual activity detection sensors are arranged along a depth direction of depth layers L2-L4 deeper than the front layer L1, for detecting activity of the cultured fishes; and a control unit 30 for providing information indicating, an activity state of the cultured fishes calculated on the basis of an activity signal from the activity detection sensors 20 arranged in the respective layers.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an activity detection device and method for cultured fish and a feeding control device for appropriately feeding cultured fish.

Background Art

[0002] In the feeding of cultured fish, it is important to perform appropriate feeding from the viewpoints of labor saving, growth efficiency, and cost reduction. Overfeeding is a waste of feed and also leads to water pollution in the sea. Therefore, as a technology related to feeding, for example, it is known from Patent Documents 1 to 5.

[0003] The feeding method and feeding system for cultured fish described in Patent Document 1 are such that when the cultured fish pulls the artificial bait, the contact switch is activated, and a signal from the contact switch is output to the control device, which is then judged by the control device and reflected in the feeding from the automatic feeder.

[0004] The feeding method and device for aquaculture described in Patent Document 2 are to feed a small amount of feed for testing, and feed the amount of feed required for fish farming only when the feeding behavior of fish for the small amount of feed is detected by ultrasonic waves.

[0005] The automatic feeder for a fish basket described in Patent Document 3 includes a feeding means that performs a feeding operation for a short time at a preset timing, a first sensor and a second sensor that are installed so as to float on the water surface and detect the number of fluctuations and the fluctuation period of the water surface, a first sensor installed at the feeding position in the fish basket, a second sensor installed at a position where there are no fish, and a control unit that compares the detection result of the first sensor and the detection result of the second sensor during the feeding operation, and if the two detection results do not match within a preset range, sends a feeding continuation signal to the feeding means.

[0006] The automatic feeding device described in Patent Document 4 starts the feeder when the preset feeding time arrives, unconditionally releases feed into the fishpond for 5 minutes, and after 5 minutes, it instructs the fish group sensor to transmit and receive ultrasonic waves, and counts the reflected waves from the cultured fish in the deep band in units of 5 minutes. If the count value is equal to or greater than a predetermined number, it is considered that there are many satiated cultured fish, and the feeding operation by the feeder is temporarily stopped. If the count value is less than the predetermined number, it is considered that there are still many cultured fish in the process of feeding, and the feeding operation by the feeder is continued.

[0007] The feeding system and feeding method described in Patent Document 5 stop the feeding by the feeding device when the movement of the image shown by the image data acquired by the camera during the feeding of the feeding device to the cultured fish in the fishpond becomes equal to or less than a predetermined amount.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, in the feeding method and feeding system for cultured fish described in Patent Document 1, since the feeding demand of cultured fish is detected using dummy bait, it is not suitable for cultured fish that always swim at high speed like tuna because they do not always eat the dummy bait.

[0010] The method and apparatus for feeding aquaculture feed described in Patent Document 2 irradiate ultrasonic waves toward the water surface to detect the feeding behavior of fish, so the accuracy deteriorates when the sea is rough. In addition, it is difficult to distinguish between the feed hitting the water and the feeding behavior of the aquaculture fish. Therefore, it is difficult to apply it to a large aquaculture net cage.

[0011] Since the automatic feeder for aquaculture net cages described in Patent Document 3 detects the number of fluctuations and the fluctuation period of the water surface by the first sensor and the second sensor, the accuracy deteriorates when the sea is rough.

[0012] The automatic feeding device described in Patent Document 4 counts the reflected waves from aquaculture fish by ultrasonic waves from a fish school sensor, and detects the feeding behavior of aquaculture fish based on the count value. However, for aquaculture fish that repeat aggregation and dispersion, the count value changes constantly, so the accuracy is poor. In addition, when ultrasonic waves hit the aquaculture fish on the surface layer of the aquaculture net cage, a sound wave shadow is formed there, and the situation in the deep band cannot be known.

[0013] The feeding system and method described in Patent Document 5 determine the state of aquaculture fish based on the image data acquired by a camera, so the accuracy is poor when the water quality is turbid. In addition, since the measurement range is narrow in the image data, it is only possible to determine the area around the feeding location.

[0014] For example, aquaculture net cages installed in the ocean vary in size, depth, and the number of fish accommodated. In addition, the ocean also has various water qualities and flow rates of tides. In addition, feeders also vary from veterans who feed the appropriate amount at the appropriate timing to those with little experience and unfamiliarity. Therefore, no matter what type of aquaculture net cage it is, and no matter how unfamiliar the feeder is, if the feeding activity status of aquaculture fish can be accurately grasped, optimal feeding is possible.

[0015] Therefore, the present invention aims to provide an activity detection device, an activity detection method, and a feeding control device for cultured fish, which can accurately grasp the activity status of each layer of cultured fish and adjust the feeding amount appropriately according to the activity status of the cultured fish in feeding for each individual fish basket, even for fish baskets with different conditions such as the size, depth, shape, and type of cultured fish.

Means for Solving the Problems

[0016] The activity detection device for cultured fish of the present invention includes an activity detection sensor for detecting the activity of cultured fish, which is installed on the surface layer of a fish basket in which cultured fish are cultured and one or more are installed along the depth direction of a deep layer deeper than the surface layer, and a control unit for providing information indicating the activity state of the cultured fish calculated based on the activity signals from the activity detection sensors installed in each layer. , the activity detection sensor measures the radially spreading flow velocity generated by the swimming of the cultured fish school It is characterized by the above.

[0017] In addition, the activity detection method for cultured fish of the present invention provides information indicating the activity state of the cultured fish calculated by the control unit based on the activity signals indicating the activities of the cultured fish from the activity detection sensors installed on the surface layer of the fish basket in which the cultured fish are cultured and one or more are installed along the depth direction of a deep layer deeper than the surface layer. In the method for detecting the activity of cultured fish, the activity detection sensor measures the radially spreading flow velocity generated by the swimming of the cultured fish school It is characterized by the above.

[0018] According to the activity detection device and the activity detection method of the present invention, since the activity detection sensor is installed on the surface layer and one or more are installed along the depth direction of a deep layer deeper than the surface layer, the activity status of the cultured fish in each depth zone can be grasped.

[0019] The activity detection sensor can be formed by a flow velocity sensor for measuring the flow velocity.

[0024] In the feeding control device of the present invention, the control unit in the activity detection device for cultured fish of the present invention by , a feeding device for automatically performing feeding the Control feeding control device that does When the information indicating the activity state of the cultured fish during feeding indicates that a predetermined amount of cultured fish has moved from the surface layer to the deep layer, the control unit is characterized by instructing the feeding device to stop feeding.

[0025] According to the feeding control device of the present invention, when a predetermined amount of cultured fish moves from the surface layer to the deep layer, the feeding device is instructed to stop feeding, so that feed that may be wasted can be suppressed.

Effect of the Invention

[0028] According to the present invention, even for cultured fish that swim at high speeds, even when the sea is rough, and even when the water quality is turbid, the activity detection sensor can accurately grasp the activity status of the cultured fish. Therefore, even in fish cages with different conditions such as the size, depth, shape, and type of cultured fish, the feeding amount can be appropriately adjusted according to the activity status of the cultured fish's feeding for each individual fish cage.

Brief Description of the Drawings

[0029] [Figure 1] It is a diagram showing a feeding control device using an activity detection device according to an embodiment of the present invention. [Figure 2] It is a diagram for explaining the sensor device and the device main body of the feeding control device shown in FIG. 1. [Figure 3] It is a diagram for explaining the configuration of the control unit shown in FIG. 2. [Figure 4] It is a graph of the flow rate showing the feeding of yellowtail.

Embodiments for Carrying Out the Invention

[0030] A feeding control device using an activity detection device for cultured fish according to an embodiment of the present invention will be described based on the drawings. The feeding control device 10 shown in Fig. 1 is designed to perform feeding with high efficiency and little waste. In this embodiment, if the feeding device F is an automatic feeding device, the feeding control device 10 can automatically feed. If the feeding device F is fed manually by a feeder, the feeding control device 10 can give instructions regarding feeding to the feeder or provide information about the activity status of the cultured fish. Note that Fig. 1 shows the case where the feeding control device 10 is connected to the control unit, the feeding device F, and the flow velocity sensor by wired communication, which will be described in detail later.

[0031] The feeding control device 10 is installed on the surface layer L1 of the fish cage C in which the cultured fish are cultured, and one or more activity detection sensors 20 for detecting the activities of the cultured fish are installed along the depth direction of the deep layers L2 to L4 deeper than the surface layer L1. The feeding control device 10 also includes a control unit 30 that presents information indicating the activities of the cultured fish by calculating based on the activity signals from the activity detection sensors 20 installed in each layer (surface layer L1, deep layers L2 to L4) and controls the feeding device F.

[0032] The activity detection sensor 20 is formed by a flow velocity sensor. The activity detection sensor 20 includes a surface layer sensor 21 arranged on the surface layer L1 and deep layer first sensors 22 to deep layer third sensors 24 installed in the deep layers L2 to L4. In this embodiment, the activity detection sensor 20 is stored in the sensor device 40 shown in Fig. 2(A). Note that Fig. 2(B) shows the case where the control unit is connected to the feeding device and the control unit is connected to the flow velocity sensor (sensor device 40) by wireless communication.

[0033] The sensor device 40 is installed at four locations around the outside of the fish cage. A weight 41 is provided at the lower end of the sensor device 40. The sensor device 40 stores four flow velocity sensors in a case 42 as the surface layer sensor 21 and the deep layer first sensors 22 to deep layer third sensors 24. In this embodiment, there are four flow velocity sensors, but if only the cultured fish located in the layer to be detected need to be detected, one sensor may be sufficient. Also, depending on the depth of the fish cage, there can be two or three sensors, or five or more sensors. When multiple sensor devices 40 are used, it is desirable to arrange them at equal intervals around the net cage because it can suppress the bias in the measurement results.

[0034] The surface layer sensor 21 and the deep layer first sensor 22 to the deep layer third sensor 24 can be installed at arbitrary depths. For example, the surface layer sensor 21 is installed so as to be located at a water depth of 0.4 m. Also, the deep layer first sensor 22 to the deep layer third sensor 24 can be installed at arbitrary depths. The deep layer first sensor 22 to the deep layer third sensor 24 can determine the depth of each layer to be detected, for example, based on the relative depth from the surface layer sensor 21. By doing so, each sensor (surface layer sensor 21, deep layer first sensor 22 to deep layer third sensor 24) can be installed according to the depth of the net cage and the depth of each layer as the observation target set according to the fish species. For example, the sensors can be installed at equal intervals, or the interval can be gradually increased or decreased. In the present embodiment, the deep layer first sensor 22 to the deep layer third sensor 24 can be installed, for example, every 3 m from the surface layer sensor 21. By installing the deep layer first sensor 22 to the deep layer third sensor 24 at equal intervals from the surface layer sensor 21, the depth of each layer can be set evenly, and the cultured fish located in each layer can be detected.

[0035] As shown in FIG. 2B, the activity detection sensor 20 (surface layer sensor 21 and first to third deep layer sensors 22 to 24) includes a propeller 20a, a rotation detector 20b, and a communication module 20c. The propeller 20a is attached to the tip of a rotating shaft and rotates with the water flow. The rotation detector 20b detects the rotation of the rotating shaft and outputs a signal (activity signal) indicating the flow speed. The rotation detector 20b may be, for example, a photointerrupter that blocks light from the light-emitting element to the light-receiving element when the rotating shaft rotates. Therefore, the activity signal from the rotation detector 20b is rotation information indicating the rotation of the rotating shaft. The communication module 20c converts the activity signal from the rotation detector 20b into a communication signal and transmits it over a communication line. The communication module 20c may be, for example, a device capable of LAN communication via 100Base-T or 1000Base-T.

[0036] The sensor device 40 also includes a communication unit 43 that communicates with each communication module 20c to aggregate information. The communication unit 43 includes a concentrator 43a that aggregates communication lines from the communication modules 20c, and a short-range communication terminal 43b that wirelessly communicates signals from the concentrator 43a to the control unit 30. The concentrator 43a may be, for example, a LAN hub, and the short-range communication terminal 43b may be a communication terminal that communicates by WiFi (registered trademark).

[0037] The sensor device 40 communicates with the device main body 50 . The device main body 50 is equipped with a short-range communication base unit 51 that communicates with each sensor device 40 and outputs to the control unit 30, the control unit 30, and a long-range communication device 52 for notifying information from the control unit 30. The short-range communication master unit 51 is a master unit that communicates with each of the short-range communication slave units 43b. The long-range communication unit 52 is a communication unit that transmits information provided by the control unit 30 to the feeder. The long-range communication unit 52 can be, for example, a wireless communication unit such as 3G, 4G, or 5G used in mobile phones.

[0038] Next, the control unit 30 will be described with reference to FIG. 3. As shown in FIG. 3, the control unit 30 includes a first communication unit 31a, a second communication unit 31b, a flow velocity calculation unit 32, an activity information calculation unit 33, an activity information providing unit 34, an automatic feeding control unit 35, and a storage unit 36.

[0039] The first communication unit 31a receives an activity signal (rotation information) from the short-range communication master device 51 (see FIG. 2(B)) and outputs it to the flow velocity calculation unit 32. The second communication unit 31b communicates with the portable terminal device T (see FIG. 1) carried by the feeder. In the present embodiment, the second communication unit 31b transmits information (activity information) indicating the activity of the cultured fish from the activity information providing unit 34 to the feeder's mobile phone (smartphone) via the long-distance communication device 52.

[0040] The flow velocity calculation unit 32 calculates the frequency per unit time based on the rotation information from the sensor device 40 (activity detection sensor 20) and calculates the flow velocity (flow velocity information). The activity information calculation unit 33 calculates information (activity state information) indicating the activity state of the cultured fish based on the flow velocity information indicating the activity of the cultured fish calculated by the flow velocity calculation unit 32. The activity information providing unit 34 provides the information calculated by the activity information calculation unit 33 from the long-distance communication device 52 to the feeder's mobile phone via the second communication unit 31b. The automatic feeding control unit 35 outputs an instruction for controlling the feeding device F based on information indicating the activity of the cultured fish. In the present embodiment, the control unit of the activity detection device that provides the activity status of the cultured fish is configured by the flow velocity calculation unit 32, the activity information calculation unit 33, and the activity information providing unit 34, excluding the automatic feeding control unit 35. The storage unit 36 stores and saves various data, and can be a hard disk or a flash memory.

[0041] The operation and usage status of the feeding control device 10 according to the embodiment of the present invention configured as described above will be described with reference to the drawings. When a water current generated by a tidal current or the swimming of farmed fish strikes the activity detection sensor 20 of the sensor device 40 installed in the fish pen C shown in Fig. 1, the propeller portion 20a of the activity detection sensor 20 shown in Fig. 2(B) rotates. When the propeller portion 20a rotates, the rotation detector 20b detects the rotation and outputs a signal corresponding to the rotation speed as an activity signal to the communication module 20c.

[0042] The communication module 20c converts the activity signal into a communication signal and transmits it to the communication unit 43 together with information for identifying the sensor device 40 (identification information) and information for identifying the depth. The information for identifying the sensor device 40 can be numbers assigned to the four sensor devices 40 or the circumferential positions of the four sensor devices 40. In addition to being built into each sensor device 40, the information for identifying the sensor device 40 can also be measurement information if a positioning device such as a direction sensor or a GPS (Global Positioning System) is provided in the sensor device 40. In this embodiment, the communication module 20c converts the activity signal from the rotation detector 20b into a communication signal and outputs it.

[0043] When a communication signal from each sensor device 40 is input to the concentrator 43a of the communication unit 43, it is transmitted to the device main body 50 by the short-range communication slave device 43b. In the device main body 50 , when the short-range communication master device 51 receives the communication signal from the sensor device 40 , the communication signal is output from the short-range communication master device 51 to the control unit 30 .

[0044] 3, the first communication unit 31a receives the communication signal. The flow velocity calculation unit 32 calculates the flow velocity (flow velocity information) by calculating the frequency per unit time based on the rotation information indicated by the communication signal from the first communication unit 31a. Then, the activity information calculation unit 33 calculates activity state information indicating the activity state of the farmed fish for each depth zone based on the flow velocity information indicating the activity of the farmed fish calculated by the flow velocity calculation unit 32.

[0045] The activity information calculation unit 33 can directly use the flow velocity information calculated from the rotation information as the activity state information, and can also use the activity state information as an exponent. For example, based on the flow velocity information measured when the cultured fish are full, the flow velocity information during fasting or feeding can be expressed as a percentage.

[0046] At this time, the activity information calculation unit 33 can cancel the flow velocity due to the tidal current. For example, first, the flow velocity is measured by the activity detection sensor 20 in a stable environment before feeding, and the flow velocity and direction at that time are stored in the storage unit 36 as the flow velocity information due to the tidal current. Then, the flow velocity information due to the tidal current is subtracted from the flow velocity information due to the cultured fish measured during the measurement. By doing so, the influence of the measurement by the tidal current can be eliminated.

[0047] When the cultured fish group swims, a flow velocity that radiates radially in the horizontal direction (the same depth zone) is generated centering on the position of the cultured fish group. In the present embodiment, four sensor devices 40 are arranged at predetermined intervals, for example, at equal intervals along the periphery of the net cage C, and the activity detection sensor 20 is arranged facing the center of the net cage C. Therefore, the activity information calculation unit 33 can calculate the central position of the flow velocity and the radial flow velocity for each depth zone from the flow velocity information from the four activity detection sensors 20 at the same depth and the position information of the activity detection sensors 20. By calculating the central position of the flow velocity and the radial flow velocity, the activity information of the cultured fish can be calculated without problems even if the swimming position of the cultured fish changes.

[0048] In this way, as long as it is a sea condition (other than typhoons, etc.) in which the feeder can feed, the fasting state can be stably estimated from the activity state of the cultured fish at any time based on the central position of the flow velocity and the radial flow velocity for each depth zone. Therefore, since the fasting state of the cultured fish can be quantitatively represented from the flow velocity distribution for each depth zone, the feeder can easily adjust the feeding amount and the feeding speed.

[0049] The activity information providing unit 34 outputs the activity state information for each depth zone calculated by the activity information calculation unit 33 to the second communication unit 31b. Then, the activity state information output to the second communication unit 31b is provided from the long-distance communication device 52 to the mobile phone of the feeder.

[0050] From the activity state information for each depth zone displayed on the mobile phone, the feeder can grasp the position of the cultured fish and the degree of aggregation of the cultured fish, and can grasp the distribution and movement of the cultured fish for each depth zone, so that the hungry state and the full state can be recognized.

[0051] Therefore, when the cultured fish move to the surface to feed on the feed, from the activity state information based on the flow velocity detected by the surface sensor 21, the feeder can recognize that the cultured fish are distributed on the surface. Next, by recognizing from the activity state information that the flow velocity detected by the surface sensor 21 has become small and that the cultured fish are detected by the first deep sensor 22 to the third deep sensor 24, the feeder can recognize that the full cultured fish have begun to disperse in the depth direction.

[0052] Furthermore, as the flow velocity detected by the surface sensor 21 becomes small and the flow velocity detected by the first deep sensor 22 to the third deep sensor 24 becomes large, the feeder can recognize that the full cultured fish have moved from the surface to the middle layer or the bottom layer of the net cage. Therefore, the feeder can accurately grasp the activities of the cultured fish from the activity state information displayed on the mobile phone.

[0053] The automatic feeding control unit 35 can output an instruction for controlling the feeding device F based on the activity state information indicating the activities of the cultured fish. For example, it can be recognized that the cultured fish have become full after feeding on the feed scattered by the feeding device F that started feeding according to time, by the fact that the flow velocity detected by the surface sensor 21 becomes small and the flow velocity detected by the first deep sensor 22 to the third deep sensor 24 becomes large. Therefore, the automatic feeding control unit 35 can instruct the feeding device F to stop automatic feeding. Also, if the feeding device F is for manual feeding, the automatic feeding control unit 35 can directly instruct the feeder to stop feeding instead of providing the activity state information to the feeder.

[0054] As described above, in the feeding control device 10 according to the embodiment of the present invention, the activity detection sensor 20 is installed on the surface layer, and one or more are installed along the depth direction of the deep layer deeper than the surface layer. Therefore, the feeding control device 10 can acquire the activity status of the cultured fish for each depth zone. Therefore, even for cultured fish that swim at high speeds, even when the sea is rough, and further regardless of the size and depth of the net cage, the feeding control device 10 can accurately grasp the activity status of the cultured fish. Thus, even for net cages with different various conditions such as the size (width), depth, shape (round, square, rectangular, etc.) of the net cage, and the type of cultured fish, the feeding amount can be appropriately adjusted according to the activity status of the cultured fish's feeding for each individual net cage.

[0055] Also, in the feeding control device 10, the activity detection sensor 20 is formed by a flow velocity sensor. Therefore, the water flow corresponding to the swimming speed of the cultured fish can be detected. Even if there is a water flow due to the tide, the flow velocity due to the swimming of the cultured fish can be determined by relative increases and decreases. Also, it can be measured regardless of whether the water quality is turbid, and there is no restriction on the viewing angle like a camera. In this way, the feeding control device 10 that acquires the activity status of the cultured fish by the water flow from the flow velocity sensor can accurately grasp the activity status of the cultured fish. Therefore, even for net cages with different various conditions such as the size (width), depth, shape (round, square, rectangular, etc.) of the net cage, and the type of cultured fish, the feeding amount can be appropriately adjusted according to the activity status of the cultured fish's feeding for each individual net cage.

[0056] (Example) The activity status of the cultured fish was measured using the feeding control device 10 shown in FIG. 1. In this embodiment, there is one sensor device 40, and for the activity detection sensor 20, the depth of the surface layer sensor 21 is 0.4 m, the depth of the first deep layer sensor 22 is 3.4 m, and the second deep layer sensor 23 and the third deep layer sensor 24 are not provided. The net cage is made of a metal net, has a rectangular shape with a length of 10 m and a width of 10 m, and a depth of 7 m. The cultured fish is a yellowtail. The measurement results are shown in the graph of Fig. 4. In the graph shown in Fig. 4, the horizontal axis represents time and the vertical axis represents the flow velocity.

[0057] As can be seen from the graph, initially from 13:04:00 at the start of the measurement, there is no significant difference between both the surface sensor 21 and the first deep sensor 22. This is because the cultured fish were swimming at a depth deeper than the range that can be measured by the first deep sensor 22. Next, feeding is started. However, during the period t1, there is no significant difference in the water flow between the surface sensor 21 and the first deep sensor 22. This is because the cultured fish remain in the deep layer and do not surface. Next, the cultured fish that notice that the feed is being scattered little by little gradually surface. Therefore, the water flow detected by the surface sensor 21 gradually starts to increase after the period t1.

[0058] Therefore, at the start of feeding, if the feeder monitors the activity state information and keeps the amount of feed to be administered at the amount at the start of feeding until the water flow increases, the amount of feed that is fed but not eaten and settles to the bottom of the net cage can be suppressed. In addition, when the automatic feeding control unit 35 shows that a predetermined amount of cultured fish remain in the deep layer by comparing the activity state information with a threshold value or the like, the automatic feeding control unit 35 can instruct the feeding device F in Fig. 1 to feed while suppressing the feeding amount at the start of feeding.

[0059] Note that whether the difference in the water flow detected by the surface sensor 21 and the first deep sensor 22 is large or small can be determined by comparing the difference with a predetermined threshold value.

[0060] In response to the water flow detected by the surface sensor 21 increasing more than the water flow detected by the first deep sensor 22, full-scale feeding is started at 13:18:24. This indicates that the cultured fish have moved a predetermined amount to the surface.

[0061] At this time, when it is shown by comparison of the activity state information with a threshold value or the like that the cultured fish has moved a predetermined amount to the surface layer, the automatic feeding control unit 35 can instruct the feeding device F in FIG. 1 to start full-scale feeding in which the automatic feeding control unit 35 increases the amount of feeding to a predetermined amount.

[0062] By doing so, the cultured fish rises from a deeper layer deeper than the depth detectable by the first deep-layer sensor 22 to the surface layer in order to eat the feed. Therefore, although there is no significant change in the water flow detected by the first deep-layer sensor 22, the water flow detected by the surface-layer sensor 21 increases while greatly increasing and decreasing. This large increase and decrease continues during the period t2.

[0063] Then, at around 14:10, since the full-fed cultured fish passed through the depth detectable by the first deep-layer sensor 22 from the surface layer and moved to an even deeper layer, there is no significant change in the water flow detected by the first deep-layer sensor 22, but the water flow detected by the surface-layer sensor 21 gradually decreases.

[0064] Therefore, if the feeder monitors the activity state information based on the water flow detected by the surface-layer sensor 21, the feeder can grasp that the cultured fish located on the surface layer at the time of feeding has moved to the deep layer, and thus can stop feeding at an appropriate timing. In addition, when it is shown by comparison of the activity state information with a threshold value or the like that a predetermined amount of cultured fish has moved from the surface layer to the deep layer, the automatic feeding control unit 35 can instruct the feeding device F (see FIG. 1) to stop feeding.

[0065] In the present embodiment, the surface-layer sensor 21 and the first to third deep-layer sensors 22 to 24 are formed by flow velocity sensors. However, as long as they are installed on the surface layer of the fish basket and one or more are installed along the depth direction of the deep layer deeper than the surface layer so that the distribution of the cultured fish in each depth zone can be detected, other sensors may be employed.

[0066] The sensor device 40 is installed along the outer periphery of the cage C, but it may also be installed along the inner side of the peripheral wall of the cage C. However, if the sensor device 40 is installed along the inner side of the peripheral wall of the cage C, the sensor device 40 will protrude inward from the peripheral wall. This may result in a collision with a migrating fish, such as a tuna, when it swims at high speed. Therefore, in the case of farmed fish such as tuna, it is desirable to install the sensor device 40 along the outer periphery of the cage C. [Industrial Applicability]

[0067] The present invention is suitable for aquaculture, in which farmed fish are raised in fish cages by feeding. [Explanation of symbols]

[0068] 10 Feeding control device 20 Activity detection sensor 20a Propeller section 20b Rotation detector 20c Communication Module 21 Surface layer sensor 22 Deep layer sensor No. 1 23 Second sensor for deep layers 24 Third sensor for deep layers 30 Control Unit 31a 1st Communication Department 31b 2nd Communication Department 32 Flow velocity calculation section 33 Activity information calculation section 34 Activity Information Department 35 Automatic feeding control unit 36 Memory section 40 Sensor Device 41 Weight 42 cases 43 Communications Department 43a Concentrator 43b Near field communication handset 50 Device body 51 Short-range communication base station 52 Telecommunications equipment C. Fish Tank T Portable terminal device L1 surface layer Deep layer of L2 to L4 F feeding device

Claims

1. An activity detection sensor formed by a flow velocity sensor for detecting the activity of the cultured fish, which is installed on the surface layer of the net cage where the cultured fish are cultured and one or more are installed along the depth direction of the deep layer deeper than the surface layer, and a control unit for providing information indicating the activity state of the cultured fish calculated based on the activity signals from the activity detection sensors installed in each layer. The activity detection sensor is an activity detection device for cultured fish that measures the radially expanding flow velocity generated by the swimming of the cultured fish group.

2. The activity detection device for cultured fish according to Claim 1, wherein the control unit subtracts the flow velocity of the tidal current measured by the activity detection sensor before feeding from the radially expanding flow velocity.

3. The activity detection device for cultured fish according to Claim 1 or Claim 2, which measures the radially expanding flow velocity for each depth at which the activity detection sensor is installed.

4. In a method for detecting the activity of cultured fish, based on the activity signal indicating the activity of the cultured fish from an activity detection sensor formed by a flow velocity sensor installed on the surface layer of the net cage where the cultured fish are cultured and one or more are installed along the depth direction of the deep layer deeper than the surface layer, and providing information indicating the activity state of the cultured fish calculated by the control unit. The activity detection method for cultured fish is an activity detection method for cultured fish that measures the radially expanding flow velocity generated by the swimming of the cultured fish group.

5. The activity detection method for cultured fish according to Claim 4, wherein the control unit subtracts the flow velocity of the tidal current measured by the activity detection sensor before feeding from the radially expanding flow velocity.

6. The activity detection method for cultured fish according to Claim 4 or Claim 5, which measures the radially expanding flow velocity for each depth at which the activity detection sensor is installed.

7. In a feeding control device that controls a feeding device for automatically performing feeding by the control unit in an activity detection device for cultured fish, which is provided with an activity detection sensor formed by a flow velocity sensor for detecting the activity of the cultured fish, installed on the surface layer of the net cage where the cultured fish are cultured and one or more are installed along the depth direction of the deep layer deeper than the surface layer, and a control unit for providing information indicating the activity state of the cultured fish calculated based on the activity signals from the activity detection sensors installed in each layer. By arranging the four activity detection sensors at equal intervals along the periphery of the fish cage, the flow velocity of the tidal current before feeding is measured, and the flow velocity that radially spreads in the same depth zone as the cultured fish group generated by the swimming of the cultured fish group is measured. Then, the subtraction of the flow velocity of the tidal current is performed, and the control unit calculates information indicating the activity state of the cultured fish. When the information indicating the activity state of the cultured fish at the time of feeding indicates that a predetermined amount of the cultured fish has moved from the surface layer to the deep layer, the control unit is a feeding control device that instructs the feeding device to stop feeding.

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