A device and method for monitoring and treating live fish in an aquaculture cage

Abstract

A device and method for monitoring and treating live fish in an aquaculture cage (50) comprises a chamber (40) comprising a roof, a bottom and at least one wall, arranged below a water surface (47, 57), in which live fish are kept and one or more passages (45) arranged in the roof at the highest point of the roof, leading from the chamber (40) towards the water surface (47, 57) and providing the fish in the chamber access to the water surface (47, 57). The one or more passages (45) comprise a monitoring region (48), a sensor (42) configured to detect fish passing through the monitoring region and monitor at least one of health, physical development, and parasites for the fish; and a light source (44) positioned in the one or more passages (45) for treating parasites on the fish as they pass through the passage (45) towards the water surface (47, 57).

Description

[0001] A device and method for monitoring and treating live fish in an aquaculture cage

[0002] The present invention concerns a device and method for monitoring and treating live fish in Aquaculture cages. More particularly, the invention relates to treating of parasites on live fish during monitoring operations on the fish.

[0003] Background

[0004] Aquaculture business is a huge industry, which is competitive compared to other ways of producing animal derived food. The industry has greatly developed in the recent times and has large growth ambitions in the years to come. Presently, the industry is characterized by manual operations, and the level of precision is low in areas like fish counting, biomass measurement, sea lice counting, disease surveillance, as well as monitoring fish health and growth rate.

[0005] In the aquaculture industry, the fish stock is generally contained within floating cages. The cages do not prevent fish from becoming infected by parasites such as for example: sea lice, or other forms. In a confined environment such as fish cages or fish tanks the parasite infection tends to spread more rapidly due to host density than one would see in open sea conditions.

[0006] As of today, it is not uncommon to experience a 15-20 % fish loss in a production cycle, resulting in large economic losses, poor utilization of resources, poor fish feed utilization, larger discharge of nutrient salts into the environment, and poor fish well-being

[0007] (Sommerset I, Wiik-Nielsen J, Moldal T, Oliveira VHS, Svendsen JC, Haukaas A og Brun E. Fiskehelserapporten 2023, Veterinaerinstituttets rapportserie nr.

[0008] 8a / 2024).

[0009] Sea lice and several contagious diseases is a growing problem for the business. Resistance is a known phenomenon in excessive use of methods, chemicals or drugs on whole populations of a species.

[0010] The treatment regimens of today are largely performed on all the fish in a net cage, which means that up to 200 000 fish gets the same treatment. There are no mechanisms to confine treatment to individual groups. The treatment may be medication, use of chemicals, fresh water or mechanical treatment. The consequences are enhanced risk of resistance, as well as unnecessary large discharge of chemicals and drugs into the environment.

[0011] Further, the present treatment methods often involve starving fish, fish crowding operations, as well as pumping fish into a different net cage or into a fish-tank ship. A fish concentrating operation comprises making the available swimming volume for the fish smaller. This is for instance performed by decreasing the volume of the net cages, and thus, increase the density of fish. For instance, this is performed by concentrating the fish in an area for treatment in the net cages, or for concentrating the fish for transfer onto a fish-tank ship using suction hoses or landing nets.

[0012] Generally, a fish-tank ship has an integrated method of concentrating the fish when it is time to unload the live fish off the ship. For example, this may be a bulkhead, which is moveable through the tank in the ship holding the fish. This bulkhead is moved through the tank to force the fish against the part of the tank from which the fish are released.

[0013] These treatments stress the fish, inflict damage, and possible loss of mucus layer. The mucous layer (mucosa epithelia) has been shown to be very important to the fish resistance against sea lice, and pathogens.

[0014] Today, the assessment of fish health in the aqua culture industry is primarily based on manual solutions; either directly through netting fish and performing manual inspection, and possible sampling, possibly using an underwater camera and analysing the images manually. No automatic solutions have been established, for analysing fish health, or solutions monitoring single individuals over time, and no solutions are established to sort out diseased fish. Presently, different automatic systems exist for measuring biomass; however, these have an error of about 10%, and the industry is looking for solutions providing biomass measurements of greater accuracy.

[0015] Consequently, the present-day solutions are complicated and involve too much time with moving fish towards and out of the treatment area, sorting, delousing etc. As a result, the operations are expensive for the operators.

[0016] WO2017 137896 describes a device for recording and monitoring the health and physical development of live fish comprising a chamber arranged below the water surface and a channel / tube which gives the fish in the chamber access to the surface. A device for recording and monitor the health and physical development of fish is arranged in the channel / tube so that when the fish swim up towards the surface to replenish its air bladder, the fish are guided through a recording area where the fish's health and physical development are monitored. If fish is found to be of bad health or is infested with parasites, the fish can be led to other locations for treatment.

[0017] All handling of fish stresses the fish and there is thus a need for more gentle methods for treating fish.

[0018] NO331345 describes a device and a method for destroying parasites on fish, such as salmon lice on salmon in fish farms. The device comprises a camera communicating with a controlling unit which in turn communicates with a light source which is adapted to fire pulses of point shaped light which is harmful for the parasite in question. The controlling unit controls a system for optical recognition within a defined coordinate system and to detect points that exhibits contrast differences typical for parasites on a fish surface and to trigger a light pulse from the light source when the coordinates for at detected point coincides with the coordinates for the aiming point of the light source.

[0019] However, this method relies on detection, tracking, and targeting of sea lice, which are typically between 1mm and 8mm, and hard to resolve in poor water conditions. Also, this requires advanced computer vision & control systems. Furthermore, it is important that such a device reaches all the fish in a cage / pen to prevent fish from infesting each other. Further, the effect of the method is limited to the later stages of lice that can be recognized, thus resulting in limited effect on keeping the lice infestation levels under control.

[0020] Consequently, there is a need for new methods of monitoring and treating fish in aqua culture plants.

[0021] The object of the present invention is to provide a device and a method of recording and monitoring health and physical development of fish and controlling parasite infestation of the fish.

[0022] The object of the invention is achieved by the features of the patent claims.

[0023] The term chamber should in this specification be understood as any kind of device that keeps the fish in a defined volume, ie. a fencing or enclosure that limits the fish’ movement to a defined volume. The chamber may be arranged under water or at land and may be made of net, such as regular fish net pens or fish corrals commonly installed in the sea, recirculating aquaculture systems (RAS), plastic, tarpaulin, concrete ponds, etc.

[0024] The term parasite should in this specification be understood to include any organism that is harmful or uncomfortable for the fish, such as sea lice, worms, fungi, virus, bacteria, etc.

[0025] Summary

[0026] A system for monitoring and treating live fish in an aquaculture cage comprises:

[0027] - a chamber comprising a roof, a bottom and at least one wall, arranged below a water surface, in which live fish are kept;

[0028] - one or more passages arranged in the roof at the highest point of the roof, leading from the chamber towards the water surface and providing the fish in the chamber access to the water surface; and wherein the said one or more passages comprise:

[0029] - a monitoring region; - a sensor configured to detect fish passing through the monitoring region and monitor at least one of health, physical development, and parasites for the fish; and

[0030] - a light source positioned in the one or more passages for treating parasites on the fish as they pass through the passage towards the water surface.

[0031] The narrow passages can be designed so that only a small number of fish is allowed through, so that they can be effectively treated and monitored.

[0032] The one or more narrow passages can for example be configured to allow a predefined number (N) of the fish for treatment through the monitoring region.

[0033] In some configurations, the narrow passage comprises an opening to the water surface that is in the range of 1 to 150 m2, more particularly 2 to 40 m2.

[0034] The chamber may be arranged at a depth (D) where the highest point of the roof is below 5m to 40m, such as 10m to 20m, to prevent infestation of parasites on the fish and allow favourable rearing conditions for the fish. It is known that in particular lice do not thrive at a larger depth, and keeping the chamber below this depth, will minimize new infestations.

[0035] The light source can be any kinds of light source that is able to emit light with characteristics suitable for treatment of fish. The light source may be a laser, such as a pulsed laser or continuous laser, or other kind of light source, and the light may be visible light, infrared light, UV light or other wavelengths that are suitable for the purpose.

[0036] The monitoring region is at least a part of the narrow passage where the sensor is arranged to monitor the fish.

[0037] The device may comprise a data processor and a memory unit and the data processor can be configured to analyse sensor data and identify features of the fish that is particularly suited for characterizing individual fish and store the characteristics in the memory unit.

[0038] The sensor may comprise at least one camera and the data processor can be configured to analyse images captured by the at least one camera.

[0039] Description of the drawings

[0040] The invention will now be described in more detail using examples, and with reference to the appended Figures.

[0041] Figure 1 schematically shows an example of a device for recording and monitoring fish health.

[0042] Figure 2 schematically shows an example of a system for monitoring and treating live fish in an aquaculture cage. Figure 3 schematically shows another example of a system for monitoring and treating live fish in an aquaculture cage.

[0043] In the description of figures, a device for recording and monitoring health and physical development of fish is generally disclosed as a fish health scanner.

[0044] Figure 1 schematically shows a device for recording and monitoring fish health, comprising two imaging devices in the form of cameras 3 which images fish localised in a monitoring region, to record fish health and fish wellbeing of single individuals swimming freely, e.g. in an aqua culture net cage. The imaging data are processed by a data processor 1 to analyse images from the imaging device and identify features of the fish characterising health condition and individuals. Data / features for each individual are stored in a database / registry 2 for later use.

[0045] In an example, the characteristics of the fish specific to the individuals such as salmon may be identified and recorded and stored in the database 2. In an example, characteristics are such as size, weight, color, spots, fins, shape etc.

[0046] In an example, the imagining device is a surveillance camera that is specialized to capture video and images of the desired fish such as salmon. The captured images are compared with a predefined image in the database 2 for comparison and analysis as described above. The analysis may employ imagine processor techniques that are known and will not be elaborated herein.

[0047] Throughout the description, salmon lice is used as an example of a parasite. However, it must be understood that they may be other forms of parasites such as fungi, worms, virus, bacteria that may also be treated.

[0048] In other examples, the device may also be configured for monitoring health and physical development of other species and varieties of fish and other sea creatures.

[0049] Figure 2 schematically shows an embodiment of a system for monitoring and treating live fish in an aquaculture cage 50. The aquaculture cage 50 shown comprises a chamber 40 where the fish are kept. This is maintained below the water level at a desired or predefined depth. The fish are kept in chamber 40, and, thus, are forced to remain at a predefined depth D below the surface to avoid sea lice and other parasites, which are mainly residing in the upper layers of the water column. This depth ensures that the fish are protected from harmful parasites such as sealice, while also providing the necessary favourable conditions in terms of water temperature and quality for healthy wellbeing of the fish. The range of the depth may vary between 2 to 100 meters depending on the type of fish and the rearing conditions but will more common be held at 10 to 50 meters or 10-20 meters below the surface.

[0050] The chamber 40 comprises a roof 51, a bottom 52 and at least one wall 53, and the roof 51 tapers upwards into one or more passage 45. The passage may be narrow to limit the number of fish being present at the same time. The passage 45 is positioned such that it provides access for the fish to the water surface 47. There may be one or more such narrow passages 45 depending on the aquaculture cage and the specifies of fish reared.

[0051] The narrow passage 45 comprises an upper volume 41 that leads from the passage to the upper opening of the water surface 47 , a monitoring region 48 and a sensor 42 configured to detect fish passing through the monitoring region and monitor at least one of health and physical development of the fish, and parasites on the fish. The narrow passage 45 also comprises a light source 44 for treating parasites on the fish as they pass through the passage 45 towards the water surface 47.

[0052] The width and depth of the narrow passage 45 is configured to be such that it allows a limited number of fish to freely swim through it, this ensures that most of the fish that pass through the narrow passage 45 are monitored and treated in a monitoring region 48 within the passage 45.

[0053] As an example, the narrow passage 45 may be in the range of 1 to 150 m2, for example 2-40 m2

[0054] In the monitoring region 48 in the passage 45, the sensor 42 monitors the fish as they swim through. In fig 2, the arrow 48 shows the monitoring region. The sensor may be a fish health scanner, that scans the fish as they swim through. The fish health scanner 42 produces high quality video and images of the scanned fish and sends them to the data processor. The passage 45 also comprises a light source 44 that is positioned within and is configured to emit light with characteristics suitable for treatment of fish. In one example, the light source 44 is a laser light source and is configured to emit laser with wavelength and intensity needed to treat the fish. The laser light emitted is directed towards an area with high probabilities of hitting parasites such as sea lice on the salmon and may be employed to make them ineffective or kill the sea lice on the surface of the salmon.

[0055] Sea lice is used as an example of a parasite and other forms of organisms may also be treated employing light source 44 and various forms of light such as UV, infrared, laser etc.

[0056] In other examples, the light source 44 may emitted different from of light such as UV light, infrared light etc to treat different forms of parasites or organisms.

[0057] This system utilizes that salmon has an open-air bladder, which has to be replenished with air every 2-14 days. Then, the fish will swim towards the available surface through the passage and the upper volume in the net cage. This cyclic migration to the surface is exploited to guide fish through the monitoring region where it is monitored by the sensor such as a fish health scanner 42. The fish can freely swim back down again the way they came up, giving even more monitoring and treatment opportunities. The fish are attracted downwards to get food, and may also be stimulated by light, water conditions or geometry of the net cage. In the aquaculture cage 50, the fish within chamber 40 are cyclically attracted towards the narrow passage 45 to get access to the surface, as described above. The fish swim up through a passage 45 where the monitoring region 48 is located. Since all fish need to pass to fill their swim bladder, they will all over time be scanned and potentially treated. Each fish can be given a unique identification ID based on pattern recognition or physical tags. This ensures that all the fish are treated if required or at least monitored for parasites and other health issues. The information on the treatment can be linked to the fish ID and stored in the database. This may then be employed at a later stage to analyse the treatment efficiency and development of health conditions.

[0058] The system may also comprise additional sensors or secondary monitoring systems which are not shown, however, it must be understood to lie within the scope of the present disclosure.

[0059] Figure 3 shows an alternative embodiment of system for monitoring and treating live fish in an aquaculture cage 50. This alternative embodiment is similar to the embodiment in fig. 2, except that instead of the upper volume 41 interfacing with the water surface 47, the chamber 40 is provided with an air-dome 49 arranged at the upper end of the narrow passage 45. The air-dome 49 is similar to an open air set up as in figure 2, but instead comprises an enclosed air volume 58 in form of an air pocket above a submerged water surface 57.

[0060] As the fish swim through the narrow passage 45 they pass through the monitoring region 48 with a sensor, such as a fish health scanner 42, that scans the fish and monitors data on the fish health as described above. The fish can then be treated by the light source 44, for example by using the laser light to remove salmon lice. The fish then swim on towards the open air-dome 49 to get air to fill their swim bladders. The enclosed air volume may be connected to an air inlet above the water surface 47 in order to refill air when necessary.

[0061] Reference numerals:

Claims

CLAIMS1. A system for monitoring and treating live fish in an aquaculture cage (50), wherein the system (50) comprises:- a chamber (40) comprising a roof, a bottom and at least one wall, arranged below a water surface (47, 57), in which live fish are kept;- one or more passages (45) arranged in the roof at the highest point of the roof, leading from the chamber (40) towards the water surface (47, 57) and providing the fish in the chamber access to the water surface (47, 57); and wherein the said one or more passages (45) comprise:- a monitoring region (48);- a sensor (42) configured to detect fish passing through the monitoring region and monitor at least one of health, physical development, and parasites for the fish; and- a light source (44) positioned in the one or more passages (45) for treating parasites on the fish as they pass through the passage (45) towards the water surface (47, 57).

2. The device according to claim 1, wherein the one or more passages (45) is a narrow passage (45) and configured to allow a pre-defined number (N) of the fish for treatment through the monitoring region (48).

3. The device according to claim 2, wherein the narrow passage (45) comprises an opening (46) to the water surface (47) being in the range of: 1 to 150 m2, more particularly 2 to 40 m2.

4. The device according to any one of the preceding claims, wherein the chamber (40) is arranged at a depth (D) where the highest point of the roof is below 2m to 40m, such as 10m to 20m, to prevent infestation of parasites on the fish and allow favourable rearing conditions for the fish.

5. The device according to claim 1, wherein the monitoring region (48) is fully or partly immersed below the water surface (47).

6. The device according to any one of the preceding claims, comprising a data processor and a memory unit, wherein the data processor is configured to analyze sensor data and identify features of the fish that is particularly to characterize individual fish and store the characteristics in the memory unit.

7. The device according to any one of the preceding claims, wherein the sensor comprises at least one camera and the data processor is configured to analyse images captured by the at least one camera.

8. The device according to any one of the preceding claims, wherein the light source (44) is one of: laser light, infrared light, UV light.

9. A method for monitoring and recording health and physical development of live fish in an aquaculture cage (50), wherein the method comprises placing fish in a chamber (40) arranged at least partly below a water surface (47), wherein the said method further comprises:- providing the fish in the chamber (40) access to the water surface (47,57) via one or more narrow passages (45), wherein the said passage (45) leads from the chamber (40) up to the water surface (47,57),- detecting when the fish pass through a monitoring region (48) in the passage (45) and monitor at least one of health, physical development, and parasites for the fish ; and- treating the fish for parasites in the monitoring region (48) by employing a light source (44), as the fish pass through the monitoring region towards the water surface (47, 57).

10. The method according to claim 10, comprising analysing detected data and identifying characteristics of the fish that characterize the individual fish and store the characteristics in a memory unit.

11. The method according to claims 9 to 10, comprising providing a unique ID for each fish that passes through the monitoring region (48) and wherein the said unique ID allows feedback on the success of the treatment and / or recovering of the fish.

12. The method according to one of the claims 9 to 11, wherein the chamber (40) comprises a roof, a bottom and at least one wall, and the one or more passage (45) is arranged in the roof at the highest point of the roof, leading from the chamber (40) towards the water surface (47, 57).

13. The method according to one of the claims 9 to 12, wherein the monitoring region (48) is arranged in the one or more passage (45) and monitoring at least one of health, physical development and parasites is done in the monitoring region (48) .

Images