WO2018212665A1

WO2018212665A1 - Apparatus for rendering an external parasite on a fish harmless

Info

Publication number: WO2018212665A1
Application number: PCT/NO2018/050128
Authority: WO
Inventors: Johan LINDHOM
Original assignee: Fjordtech Flekkefjord As
Priority date: 2017-05-16
Filing date: 2018-05-16
Publication date: 2018-11-22
Also published as: NO20170807A1; NO343135B1

Abstract

Apparatus (1) for rendering an external parasite on a fish harmless, the apparatus (1) comprising a submersible hull (10) provided with an energy system (20), a propulsion system (30) and a navigation system (50), the apparatus (1) further comprising means of identifying aquatic organisms, a control system (90) arranged to move the apparatus (1) to a vicinity of the fish or the parasite, and a tool (82) arranged to render the parasite harmless.

Description

APPARATUS FOR RENDERING AN EXTERNAL PARASITE ON A FISH HARMLESS

The invention relates to an apparatus for rendering an external parasite on a fish harmless. The invention relates, more particularly, to an apparatus comprising a submersible hull or a framework provided with an energy system, a propulsion system and a navigation system, and the apparatus comprising means of identifying parasites and fish, a control system arranged to move the apparatus to a vicinity of the parasite or fish, and a tool arranged to render the parasite harmless.

Background of the invention and prior art

Salmon lice (Lepeophtheirus salmonis) are a common parasite on salmonoids and live and reproduce on salmon and trout in sea water. Salmon lice inflict the fish with wounds that may give infections, problems with the salt balance and reduce the growth of the fish. Lice larvae that are in the infective stage are found, first and foremost, in the uppermost 10 metres below the water surface. Harmful algae that may secrete toxins are also found in the uppermost part of the water column.

Salmon in floating fish farms are especially susceptible to salmon lice. A salmon has an open swimbladder and the salmon must therefore rise to the water surface to swallow air for the swimbladder. Consequently, for shorter or longer periods, salmon will have to stay in the upper part of the water column where the concentration of salmon lice is largest.

The treatment of salmon louse is done, in the main, by using chemicals mixed into the water, so-called bath treatment, or by an active substance having been mixed into the feed. The feed is spread across the water surface and sinks down the water column. The treatment may have a negative influence on the surroundings. Salmon lice can develop resistance to the drugs used, and the treatment is resource-demanding and costly. Bath treatment also leads to the fish becoming stressed and having increased mortality. The treatment also makes the growth suffer in the treatment period. External crustacean parasites, an example of which is the salmon louse, may also be combated with so-called cleaner fish which remove and eat ectoparasites on other larger fish, for example salmon. The types of cleaner fish used the most are wrasse caught in the wild and farmed lump-sucker fish. The availability of wrasse caught in the wild is, to a great degree, dependent on the stock of wild fish, time of year and diseases. Great demand for wrasse has created a risk of overfishing the wrasse. Furthermore, the wrasse is sensitive to temperature and therefore not suitable by low temperatures.

The amount of cleaner fish in a farming cage may constitute about 20 per cent of the number of farmed fish in the farming cage. Accordingly, in a farming cage with 10 000 farmed fish, there may be about 2000 cleaner fish. Surveys show that as little as between 10 and 15 per cent of the cleaner fish eat effectively on farmed fish infected with salmon lice. The rest of the cleaner fish eat from other fish, fouling on the farming cage or they eat other organisms in the water. The low effectiveness makes the use of cleaner fish expensive, and, at the same time, cleaner fish may have a negative environmental effect in the farming cage.

Patent document NO304171 discloses a device for removing parasites externally on a fish, especially salmon lice. The fish is led into a water current where the fish is exposed to water jets from nozzle heads or nozzle slits directed towards its circumference. One drawback of this method is that the fish becomes stressed.

Patent document N0335947 discloses a device for a louse sail around the farming cage. The louse sail is extended between the upper edge of the farming cage and a submerged frame around the farming cage, so that the louse sail will have an angle of up to 45 degrees. The sail extends to a depth below the living area of the salmon louse. Drawbacks of this solution are the facts that the louse sail prevents access by vessels to the farming cage, and that the louse sail is resource-intensive to install and remove.

Patent document N0333479 discloses a device for insulating a farming cage against undesired organisms, by surrounding the farming cage with a fine-meshed fluid- permeable net. This solution requires fresh water to be pumped into the farming cage.

Patent document WO2015009160 discloses an apparatus for rendering ectoparasites harmless by the apparatus emitting an electric pulse which kills or weakens the salmon louse. Patent document N0331345 discloses a device for rendering parasites on a fish, for example salmon lice, harmless by using a laser. The device comprises a cam- era, a system for optically recognizing parasites and a light source arranged to emit pulses of a point-shaped light that is harmful to the parasite in question. The device is stationary and has a relatively high inaccuracy and thereby problems in hitting the salmon louse. There is a question whether the laser beam may harm the fish if it does not hit the salmon louse and instead hits, for example, the eye of the fish.

Patent document NO20130561 discloses a device for collecting and destroying lice in water, wherein a pump sucks lice and water through slits or openings and into a body where the mixture of lice and water is carried to a mill for destruction.

Patent document WO2015043603 discloses a pump system for removing parasites from a fish, wherein the fish is pumped from a first volume into a second volume. Between the first and second volumes, a plurality of nozzles are arranged, arranged to flush the parasites loose. The loose parasites are separated from the fish by the parasites following the water flow out of the device, whereas the fish is guided into the second volume.

Patent document WO2016120071 discloses a robotized manipulator arm comprising a propulsion system and a tool. The tool may be either an inspection tool with a camera, a manipulator tool or a gripper tool.

The invention has for its object to remedy or reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art.

The object is achieved through the features that are specified in the description below and in the claims that follow.

The invention is defined by the independent claims. The dependent claims define advantageous embodiments of the invention.

General description of the invention

In a first aspect, the invention concerns an apparatus for rendering an external parasite on a fish harmless, the apparatus comprising a submersible hull or a framework provided with an energy system, a propulsion system and a navigation system, and the apparatus comprising means of identifying parasites and fish, a control system arranged to move the apparatus to a vicinity of the parasite or the fish, and a tool arranged to render the parasite harmless. The apparatus may further include a mounting device for the tool, wherein the mounting device may be adapted for the connection of various tools. In what follows, the apparatus will be referred to as a robotic cleaner fish. Rendering an external parasite harmless may be understood as the parasite being killed, made inactive or removed from the fish. The parasite may be a salmon louse.

The robotic cleaner fish is arranged to supplement or replace live cleaner fish in a farming cage. As described initially, a farming cage may typically include 2000 live cleaner fish, of which about 300 cleaner fish eat effectively from salmon lice. The robotic cleaner fish is arranged to continuously search for and render salmon lice harmless. A farming cage may therefore include substantially fewer robotic cleaner fish than live cleaner fish. Extensive use of known technology combined with a large production volume may make the robotic cleaner fish an economic alternative to live cleaner fish.

The robotic cleaner fish may include known technology taken from a group consisting of underwater vessels, for example an ROV (remote-operated vehicle) and an AUV (autonomous underwater vehicle).

The submersible hull may comprise a main form of a size corresponding to that of a fish, in order thereby to affect the fish in the farming cage as little as possible. In an alternative embodiment, the robotic cleaner fish may include an open frame or a frame that the fish may swim through.

The energy system may include a battery or a cabled energy supply. The battery may be replaceable or rechargeable. A rechargeable battery may be charged manually, for example by taking the robotic cleaner fish out of the water and connecting the battery to a battery charger. In an alternative embodiment, the battery may be charged via an inductive charging system. The inductive charging system may be arranged in the farming cage and comprise one or more charging stations. A plurality of charging stations may be arranged at different heights in the water column. On the basis of the number of robotic cleaner fish that are in the farming cage and the battery lifetime, a person skilled in the art may calculate how many charging stations will be necessary in the farming cage. The recharging of the battery may happen automatically by the robotic cleaner fish navigating to the charging station when the power level reaches a lower minimum limit. The connecting system of the robotic cleaner fish for the charging station may include a cable attached to the robotic cleaner fish, the cable being provided, at its free end, with means for connecting to the charging station. The means of connecting may include a magnet.

The cabled energy supply may comprise a power cable which is attached, at its first end portion, to the robotic cleaner fish and is attached, at its second end portion, to an external energy source or another robotic cleaner fish. The energy cable may include a cable for communication and a hose for a fluid.

The propulsion system may include prior-art means, for example a propeller, a water jet or a device for a fish-like movement. The propulsion system may include means of manoeuvring, for example a rudder or a thruster according to the prior art. Means of propulsion and manoeuvring may be shared. A propulsion system including a rotatable or movable component may include means that prevent the fish from coming into contact with the rotatable or movable component.

The navigation system may include prior-art means, for example a transmitter, a gyrocompass, an acoustic positioning system, or an audio-visual navigation system. The navigation system may be arranged to keep a plurality of robotic cleaner fish within one or more defined areas in the farming cage. For example, most of the robotic cleaner fish may be programmed to stay in the upper part of the water column where the concentration of salmon lice is largest.

The navigation system may include means of autonomous navigation in the farming cage or of moving the robotic cleaner fish along a defined path or to a particular point, for example a charging station. The navigation system may include means adapted for direct communication between two or more robotic cleaner fish.

The robotic cleaner fish may include a ballast system arranged to keep the robotic cleaner fish afloat at a specific depth below the water surface. The ballast system may comprise a ballast tank for water or air. In an alternative embodiment, the ballast system may comprise one or more ballast weights.

An identification system may comprise prior-art means of identifying and tracking aquatic organisms, for example parasites and fish, and the identification system may comprise a computer vision including generic and standardized algorithms used in prior-art drones. Relevant algorithms are so-called mean-shift and camshift. These are algorithms adapted for following a colour histogram, provided the object to be followed, the fish or the parasite in this case, has been identified. The identification system may include algorithms adapted for tackling zooming, rotation and panning when the fish moves relative to the robotic cleaner fish. An identification system as described may also include algorithms adapted for dynamically adjusting to the conditions in the farming cage by trial and error.

The apparatus may include a control system and a software for processing and han- dling information from said systems and a plurality of sensors arranged on the robotic cleaner fish.

The apparatus may include a communication system, and the communication system may be adapted for wireless communication between the robotic cleaner fish and an operator and between two or more robotic cleaner fish.

The apparatus may include at least one mounting device for a tool or a sensor. The mounting device may be adapted for various tools and sensors. The tool may be arranged to mechanically render the parasite harmless, to monitor the health condition of the fish in the farming cage or to count lice. The tool may be arranged to perform one or more of said tasks on a tagged fish. The tagging of the fish may be, for example, an RFID chip attached to the fish.

The tool for rendering the external parasite harmless may comprise a suction mechanism, a cutting function, an electric pulse, a light pulse, a sonic pulse with acoustic pressure or a camera. The tool may include several of the characteristics mentioned and the tool may include a sensor.

The sensor system and propulsion system of the robotic cleaner fish position the robotic cleaner fish correctly in relation to the task that the tool is arranged to perform. If the tool includes a suction mechanism, the suction mechanism may be arranged to surround the salmon louse and adhere to the fish by suction while another tool renders the salmon louse harmless.

The robotic cleaner fish may include means of counting live parasites and parasites rendered harmless. The system may also include means of recording the time and position and of identifying and removing parasites. The information may be stored in the control system and transmitted to the operator.

In a second aspect, the invention relates to a method for removing external parasites from fish in a farming cage, the method comprising the following steps:

a) providing an apparatus according to the first aspect of the invention;

b) moving the apparatus submerged in the farming cage;

c) activating an identification system including a camera, a computer vision and algorithms adapted for the identification and tracking of parasites;

d) on the recognition of a parasite, activating the control system to position the apparatus in a vicinity of the identified parasite;

e) rendering the parasite harmless by activating the tool;

f) repeating steps b)-e). The method may further comprise the steps:

a') continuously measuring the power level of the battery;

b') interrupting the search of the apparatus and identifying parasites according to steps b)-e) when the power level of the battery reaches a lower limit value;

c') activating the navigation system of the apparatus to autonomously move the apparatus to a nearest charging station;

d') autonomously connecting the secondary coil of the apparatus to a primary coil arranged in one of the docking stations of the charging station;

e') recharging the battery;

f ) releasing the apparatus from the charging station when the battery has been recharged; and

g') letting the apparatus resume search and identification according to steps b)-e). Exemplary embodiment

In what follows, an example of a preferred embodiment is described, which is visualized in the accompanying drawings, in which :

Figure 1 shows a schematic drawing of the robotic cleaner fish, and

Figure 2 shows a schematic drawing, on a smaller scale, of a plurality of robotic cleaner fish arranged in a farming cage.

Figure 1 shows a principle drawing of a robotic cleaner fish 1 comprising a submersible hull 10, an energy system 20, a propulsion system 30, a ballast system 40, a navigation system 50, a communication system 55, a sensor system 60, a light 70, a tool system 80 including a mounting device 81 for a tool and a tool 82, and a control system 90.

In the figure, the submersible hull 10 is shown having a fish-like shape to blend in as much as possible with the fish in a farming cage 3 indicated in figure 2.

The energy system 20 comprises a rechargeable battery 21 which supplies the robotic cleaner fish 1 with electrical energy. The energy system 20 includes means of controlling and monitoring the energy system 20 and associated components. The recharging of the battery 21 may be done inductively. When the power level of the battery 21 reaches a lower limit value, the robotic cleaner fish 1 automatically navigates to a submerged charging station 23 attached to the farming cage 3. The inductive recharging is done by a secondary coil 22 in the robotic cleaner fish 1 being connected to a primary coil at the charging station 23. The secondary coil 22 is attached to the robot- ic cleaner fish 1 via a flexible cable. In an alternative embodiment, the secondary coil may be attached to the submersible hull 10.

The propulsion system 30 comprises a propeller 31 arranged vertically and a propeller 33 which is arranged horizontally inside the hull and a thruster 32 in accordance with the prior art. The propeller 33 is arranged horizontally in a central passage in the submersible hull 10, and the propeller 33 is arranged to move the robotic cleaner fish 1 vertically in the water column when the rate of propulsion is zero. A pair of control fins 34 are arranged to control the robotic cleaner fish 1 in a vertical direction in the water column when the robotic cleaner fish 1 is moving forwards in the water. The propeller 31, the thruster 32, the vertical propeller 33 and the control fins 34 can be operated individually or simultaneously.

The ballast system 40 controls the buoyancy of the robotic cleaner fish 1. The ballast system 40 includes a ballast tank 41, a pressure-air tank 42 and a valve system 43 in accordance with the prior art. When the robotic cleaner fish 1 is to dive, the control system 90 of the robotic cleaner fish 1 provides for the valve system 43 to be opened so that the ballast tank 41 can fill with water until the robotic cleaner fish 1 achieves the pre-programmed buoyancy.

When the robotic cleaner fish 1 is to rise in the water column or rise to the water surface 5 for service, the valve system 43 provides for the water in the ballast tank 41 to be replaced with air from the pressure-air tank 42. To ensure that the robotic cleaner fish 1 will always get to the surface 5, the control system 90 ensures that the ballast tank 41 cannot fill with more water than there is pressure air 42 available for giving the robotic cleaner fish 1 positive buoyancy. When there is a need to replenish the pressure-air tank 42 with air, the robotic cleaner fish will stay afloat in the water surface 5 and the control system 90 will inform an operator about the need for service.

The navigation system 50 includes a prior-art underwater-navigation system. The robotic cleaner fish 1 may navigate autonomously or controlledly in the farming cage 3.

The communication system is adapted for wireless two-way communication between the robotic cleaner fish 1 and a base station 56 placed on the farming cage 3, indicated in figure 2.

The sensor system 60 comprises several sensors, typically in the form of a pressure sensor, a depth sensor, a temperature sensor, a position sensor, a laser for distance measurement and a means of reading an RFID chip. Further, the robotic cleaner fish is provided with one or more sensors 62 arranged to search for and identify salmon lice and fish. A camera 65 and a light system 70 are arranged in the forward end portion 1A of the robotic cleaner fish 1. The camera 65 is provided with a computer vision adapted for the identification of fish and parasites. The camera 65 and the sensor system 60 are connected to the control system 90.

A mounting device 81 for a tool is arranged in the forward end portion 1A of the robotic cleaner fish 1. In the figure, the tool 82 is shown with a suction mechanism arranged to surround the salmon louse. Internally, the tool 82 is provided with a device arranged to kill the salmon louse by means of an electric pulse.

All the functions of the robotic fish 1 and the functions of the tool 82 are controlled by the control system 90.

Figure 2 shows a principle drawing, on a smaller scale, of a farming cage 3 including a plurality of robotic cleaner fish 1, a navigation system 50 and two charging stations 23. In the drawing, the navigation system 50 is shown as a so-called SBL acoustic positioning system, which is known to be used for an underwater vessel, for example a UAV. The navigation system 50 includes three radio transmitters 52 attached to the farming cage 3, at a distance below the water surface 5. At its top, the farming cage 3 is provided with floating ring 4 floating in the water surface 5. The navigation system 50 can be used to purely register the positions of the robotic cleaner fish 1 or to guide the robotic cleaner fish 1 along a programmed path or within a specific area in the farming cage 3.

Two charging stations 23 are attached to the farming cage 3 at a distance below the water surface 5. The positions of the charging stations 23 are triangulated in the same way as the position of the robotic cleaner fish 1. The positions of the charging stations 23 are automatically transmitted to the navigation system 55 of the robotic cleaner fish 1. When the battery 21 of the robotic cleaner fish 1 has to be recharged, the robotic cleaner fish 1 moves to the nearest charging station 23. In the figure, the charging station 23 is shown as a ball provided with a plurality of docking stations adapted for the simultaneous recharging of several robotic cleaner fish 1. When the robotic cleaner fish 1 is in the immediate vicinity of the charging station 23, an electromagnet will attract the secondary coil 22 (see figure 1) of the robotic cleaner fish 1 and attach the secondary coil 22 to one of the docking stations of the charging station 23. When the battery 21 has been recharged, the electromagnet is deactivated and the robotic cleaner fish 1 is released.

The figure shows a typical situation of application, in which most of the robotic cleaner fish 1 have been programmed to stay in a layer A in the farming cage 3 where the occurrence of salmon lice is greatest.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative em- bodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive.

The use of the verb "to comprise" and its different forms does not exclude the presence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements. The fact that some features are indicated in mutually different dependent claims does not indicate that a combination of these features cannot be used with advantage.

Claims

C l a i m s

1. Apparatus (1) for rendering an external parasite on a fish harmless, the apparatus (1) comprising a submersible hull or a framework (10) provided with an energy system (20), a propulsion system (30) and a navigation system (50),

c h a r a c t e r i z e d i n that the apparatus (1) further comprises means of identifying parasites and fish, a control system (90) arranged to move the apparatus (1) to a vicinity of the parasite or the fish, and a tool (82) arranged to render the parasite harmless.

2. The apparatus (1) according to claim 2, wherein the tool (82) includes a suction mechanism.

3. The apparatus (1) according to any one of the preceding claims, wherein the tool (82) includes a cutting function.

4. The apparatus (1) according to any one of the preceding claims, wherein the tool (82) includes an electric pulse.

5. The apparatus (1) according to any one of the preceding claims, wherein the tool (82) includes a light pulse.

6. The apparatus (1) according to any one of the preceding claims, wherein the tool (82) includes a sonic pulse.

7. The apparatus (1) according to any one of the preceding claims, wherein the apparatus (1) includes a communication system (55).

8. The apparatus (1) according to any one of the preceding claims, wherein the apparatus (1) includes means of inductively recharging a battery (21) belonging to the energy system (20).

9. A method of removing external parasites on fish in a farming cage (3),

c h a r a c t e r i z e d i n that the method comprises the following steps:

a) providing an apparatus (1) according to claim 1;

b) moving the apparatus (1) submerged in the farming cage (3) ;

d) on the recognition of a parasite, activating the control system (90) to position the apparatus (1) in a vicinity of the identified parasite;

e) rendering the parasite harmless by activating the tool (82); and f) repeating steps b)-e).

The method according to claim 9, wherein the method further comprises the steps:

a') continuously measuring the power level of the battery (21);

b') interrupting the search of the apparatus (1) and identifying parasites according to steps b)-e) of claim 9 when the power level of the battery (21) reaches a lower limit value;

c') activating the navigation system (50) of the apparatus (1) to autonomously move the apparatus (1) to a nearest charging station (23);

d') autonomously connecting the secondary coil (22) of the apparatus (1) to a primary coil arranged in one of the docking stations of the charging station (23);

e') recharging the battery (21);

f ) releasing the apparatus (1) from the charging station (23) when the battery (21) has been recharged; and

g') letting the apparatus (1) resume search and identification according to steps b)-e) of claim 9.