EP3735127A1

EP3735127A1 - A method or apparatus for collecting marine life

Info

Publication number: EP3735127A1
Application number: EP18833497.3A
Authority: EP
Inventors: Charles Clark; Michael Bower
Original assignee: Pirie & Smith Ltd
Current assignee: UNDERWATER CONTRACTING LIMITED
Priority date: 2018-01-04
Filing date: 2018-12-28
Publication date: 2020-11-11
Also published as: GB2571003A; GB201821266D0; WO2019135070A1; GB201800103D0; GB2571003B

Abstract

A remotely operated submersible device comprising a suction means and a collection means; and method of using said device for the collection and retrieval of fish or other water creatures from an aquaculture enclosure. The suction means creates a low pressure region in an opening of the device, generating suction and a flow of water through a funnel (12) and ducting (3), entraining fish or other water creatures located at or near the funnel (12), and directing them to the collection means for subsequent removal. The collection means comprises a cage (2) made of a mesh structure (9) suitable for the containment of fish or other water creatures, while permitting water flow through the mesh (9). The device may further comprise a camera to allow visual communication between an operator and an environment of the aquaculture enclosure.

Description

A Method or Apparatus for collecting marine life

Field of the Invention

The present invention relates to a controllable, submersible device for use in aquaculture, which comprises a suction device and collection means for the collection and retrieval of, for example, dead, diseased and/or dying fish from fish farm enclosures.

Background

Sea-lice are small marine parasites which can infect many species of marine fish, including salmon. They feed on the mucus, blood and skin of salmon, and may even carry diseases, all of which can be severely damaging and even fatal to the fish. This can affect both wild and farmed fish but its impact can be particularly significant on fish farms due to the large number of fish in close proximity, primarily affecting salmon farms. This is a global issue, but it is particularly prevalent in Scotland and this issue has increased in recent years.

If sea-lice are present, due to the speed at which infestations can spread throughout the fish population, it is important to promptly remove any affected dead or dying fish to minimise the risk to other fish, since affected fish remaining in the cages can increase the prevalence of sea-lice and exacerbate the problem. Therefore, an efficient method of removing dead fish, referred to as morts, or diseased or dying fish is critical to the overall health of the remaining population of farmed fish and consequently, the efficiency and profitability of the fish farm as well as the health of wild fish in the surrounding areas.

A typical design of fish enclosures comprises a conical base to allow morts to drop to the bottom where they are collected in a device referred to as a‘deadsock’ and pumped to the surface for investigation and disposal. However, not all morts sink and drop into the deadsock, and as a result, any remaining morts have to be manually collected, for example, by scuba divers during twice-weekly cage inspections. Within Scotland, there are over a thousand farms, each of which may have up to twelve cages, and so manual inspections are clearly highly labour intensive, resulting in thousands of man-hours across the county. The use of divers is highly expensive and so such procedures add great expense to the maintenance of fish farms.

Moreover, working in such conditions can be hazardous for the diver, and as a result, dive times and frequencies are limited for the health of the diver and to minimise the risk of any diving related conditions such as decompression sickness or nitrogen narcosis. Additionally, the growing trend within the aquaculture industry is for deeper enclosures, further increasing the risk to the diver since these health conditions become increasingly more likely at greater depths. This further limits the frequency and duration for which a diver can work and thus adds to the expense of employing divers for such procedures.

This is clearly an inefficient and potentially dangerous process for removing morts, and means of diver-less intervention offer significantly safer, cheaper, and more efficient alternatives.

Submersible vehicles are widely used within the aquaculture industry, some examples of which are described below.

WO2013029100 (A1 ) describes a net clearing device for clearing objects caught by a net submerged in a body of water. The net clearing device includes a submersible net clearing head, which has a duct with a mouth at one end through which to collect objects, a flow inducing device for inducing a fluid flow through the duct from the mouth, a container in fluid communication with the duct, the duct being configured to direct collected objects into the container; and a propulsion system for moving the head about on a surface of the net.

The propulsion system comprises vertical propellers which direct the skid members onto the net, at which point, the sprockets engage with the net which allow the device to manoeuvre across the surface of the net. This only facilitates the collection of morts that have sunk to the bottom of the net. Due to the inability to manoeuvre within three-dimensional space, the device is not capable of collecting morts which are partially sunk or floating on or below the surface. This poses a significant limitation with this device since this method may not allow efficient and complete extraction of all morts within the enclosure.

WO2017189521 (A1 ) describes a system for automatically removing deceased fish from an aquaculture cage. The system may include an underwater robotic vehicle configured to traverse the aquaculture cage to collect mortalities. The mortalities, once collected, may be brought to a system dock and then removed from the cage.

Similar to WO2013029100 (A1 ) above, this device uses toothed wheels to engage with the surface of the net for mort collection. In addition, embodiments of this device may include vertical thrusters, allowing the device to rise and fall to any horizontal plane within the enclosure. However, it still limited to the surfaces of the enclosure, and is not capable of navigating three-dimensional space away from the surface of the net. WO201 1019290 (A2) discloses a remotely operated device for collecting objects from the seabed which comprises a nozzle, a suction chamber, and pump, to harvest sea creatures using suction produced by a pump or an electric thruster, and storing them in a storage box.

However, a limitation of WO201 1019290 (A2) is that there are no means for selectively collecting items from the seabed, and any matter at or near the inlet of the nozzle will be drawn into the device and retained in the storage box. Accordingly, any non-target aquatic life which gets unintentionally drawn into the device could be injured, trapped or killed; and unwanted matter such as rocks and silt may fill up the storage box, requiring it to be manually removed.

It is amongst the objects of the present invention to obviate and/or mitigate one or more of the aforementioned disadvantages.

Summary of the Invention

The present invention aims to reduce or obviate the requirement for manual removal of, for example, morts or diseased fish, especially floating morts/diseased fish by scuba divers, with a remotely operated collection means which can be controlled from the surface of the water, increasing the efficiency and safety or mort/diseased fish removal. The use of remotely operated vehicles (ROVs) offers such a solution. The use of ROVs is widespread within the offshore oil and gas industry and is also becoming increasingly used within the aquaculture industry. In addition, since divers are not required, mort or other sea creature collection can be performed more regularly and for longer periods of time.

In a first aspect there is provided a method for collecting fish and/or other water creatures from an aquaculture enclosure or the sea bed, the method comprising: providing a submersible device for collecting the fish and/or other water creatures; controlling movement of the submersible device within and around a body of water, in order to specifically manoeuvre the submersible device towards a desired (or target) fish and/or other water creature; and collecting the desired (or target) fish and/or other water creature using suction means of the submersible device.

In particular there is provided a method for collecting fish and/or other water creatures from an aquaculture enclosure, the method comprising: providing to the aquaculture enclosure a submersible device for collecting the fish and/or other water creatures; controlling movement of the submersible device in three-dimensions within and around the body of water of the aquaculture enclosure, in order to specifically manoeuvre the submersible device towards a desired fish and/or other water creature floating within the body of water; and using a suction system of the submersible device for collecting the desired fish and/or other water creature in a porous collection means which is configured to permit water and undesirable materials to pass through the collection means.

The body of water may be an aquaculture enclosure or a sea or lake for example.

In accordance with the invention, the fish and/or other water creatures, such as dead, diseased and/or dying fish and/or water creatures may thereafter be removed from the aquaculture enclosure. For the sake of clarity and brevity, hereinafter reference will generally only be made to the collection and/or removal of fish. However, this should not be construed as limiting and the present invention equally applies to the collection of any other marine life (e.g. molluscs, shellfish and the like) which may be grown in a controlled aquaculture container or enclosure, or indeed wild shellfish such as scallops which reside on the sea bed.

The present invention in some embodiments describes a method and apparatus for targeted dead (mort), diseased or dying fish collection and removal which utilises a manoeuvrable submersible device comprising a suction device for entraining dead, diseased or dying fish into a collection area of the device, so that the dead, diseased and/or dying fish can be collected and removed from an aquaculture enclosure. In one embodiment the methods and apparatus described herein may find use in the farming of salmon, where sea lice and hence salmon infection is prevalent. However, the invention may find application in the collection of any types and variety of fish or sea life which are grown in controlled aquaculture enclosures or reside in the wild on the sea bed.

As mentioned above in the background section, it may be particularly important to remove fish (dead or otherwise), which have become infected with pathogens, such as sea-lice, in order to prevent or minimise such infected fish from infecting other fish present within the enclosure. Thus, the methods of the present invention may be viewed in some embodiments as a way of improving aquaculture methods through removal of infected dead, diseased or dying fish from an aquaculture enclosure. In particular, the present invention provides a method of collection of dead, diseased and/or dying fish which are suspended in the water of the aquaculture enclosure and not just those which sink to the bottom of the enclosure and may be collected by other means. Diseased/dying fish for example may still be able to swim and float within an enclosure, but able to contact and potentially infect healthy fish. Thus, removal of such diseased and/or dying fish is advantageous. By employing a collection device the manoeuvrability of which is controllable, it is possible to ensure that only dead, diseased and/or dying fish can be removed, rather than healthy fish.

The submersible device can be retro-fitted to a submersible vehicle such as a remotely operated vehicle (ROV), or can have an integrated propulsion system. Typically the ROV may be an open or box frame ROV known in the art. The device may be manoeuvrable by way of a propulsion means which controls the three-dimensional movement of the device allowing it to manoeuvre itself to any point within the body of water such as an aquaculture enclosure, to target fish anywhere within the three-dimensional space. Thus, the present invention permits dead, diseased and/or dying fish which are floating anywhere within a tank or enclosure to be removed and not simply fish/water creatures which have sunk to the bottom of a tank or enclosure.

In a further aspect there is provided a submersible device for collecting fish and/or other water creatures, the submersible device comprising: a suction system designed to enable collection of fish from a body of water, such as an aquaculture enclosure and collection means to retain the collected fish until their removal from the device.

In one embodiment, the submersible device is designed to be retrofitted/attached to an existing underwater vehicle such as a remotely operated vehicle (ROV). In such embodiments, the suction system may be provided the vehicle in combination with the submersible device. Attachment may be made using any suitable means. Attachment may be easily reversible, so that the device can be attached/removed from the vehicle easily as required.

In another embodiment, the device is designed with an integrated propulsion device as a standalone unit for underwater navigation and fish/sea creature collection.

In accordance with the further aspect and the embodiments described above, the submersible device, or vehicle to which it may be attached, is controllably manoeuvrable such that the device/vehicle can be manoeuvred within the body of water contained within, for example, an aquaculture enclosure. In one embodiment, unlike prior art methods and apparatus, the device/vehicle of the invention does not comprise means with which to engage and/or otherwise attach to the enclosure walls or netting in order to facilitate movement of the device/vehicle. In this regard 3-dimmensional movement of the device or vehicle can be controlled within the body of water.

The suction system may create a low pressure region in an opening or mouth of the device, generating suction and a flow of water through ducting, entraining any fish/water creatures located at or near the opening/mouth of the ducting. The fish are then directed along the ducting to a collection means for subsequent removal. The collection means may comprise a basket, cage, net or bag, for example.

In an embodiment, water jets may be used for generating a low pressure region at the opening or mouth of the device. The water jets may use a subsea pump powered by the submersible device/vehicle to which the device/vehicle is attached.

In another embodiment, the water jets are powered by subsea pumps located on the device/vehicle, but fed from a remote power source via the umbilical.

In another embodiment, the water jets are fed from a surface pump via a pressurised water feed.

In one embodiment the suction system employs the use of a water jet eductor. Water jet eductors utilize the kinetic energy of one liquid to cause the flow of another. Eductors comprise a converging nozzle, a body and a diffuser and resemble syphons in appearance. In operation, the pressure energy of the motive liquid is converted to velocity energy by the converging nozzle. The high velocity liquid flow then entrains the suction liquid. Complete mixing of the motive and suction is performed in the body and diffuser section. The mixture of liquids is then converted back to an intermediate pressure after passing through the diffuser. The use of an eductor for the generation of a low pressure region has the advantage that there are no moving parts, unlike with an impeller or propeller, which may cause blockage, impede the flow of water and fish, or cause damage to fish.

The suction system typically comprises one or more ducts to direct the flow of water and fish/creatures contained therein, from the opening/mouth of the device to the collection means. The/said duct(s) may comprise a convergent nozzle which employs the venturi effect to accelerate the fluid flow and induce a reduced pressure region in the opening/mouth of the duct.

The mouth or opening may be funnel shaped so as to help guide fish or sea creatures into and through the suction system. The funnel may comprise one or more sides which are generally flat, rather than curved in nature. In one embodiment the funnel is rectangular in shape and comprises four generally flat sides. Generally speaking the opening/funnel opening should be significantly larger than the fish/sea creatures to be collected. The size of the funnel may be varied depending upon the size of fish/sea creatures to be selected. By such provision, the device can be scaled to collect small sea creates, or very large fish. With appropriate scaling suction of non-desired/non-target sea creatures or fish may be avoided or reduced.

The propulsion system of the device or vehicle to which it may be fitted, may be configured with at least one propulsion system configured along each axis, which can be operated in both forward and reverse directions to allow vertical and horizontal movement comprising vertically upwards, vertically downwards, horizontally forwards, horizontally backwards and port and starboard horizontal movement, thus allowing motion in x, y and z directions.

In another embodiment, additional propulsion systems may be implemented along each axis which can be operated independently to the first, such that different combinations of propulsion systems can allow rotation about one or more axes, resulting in the ability to manoeuvre in 4, 5 or 6 degrees of freedom, in roll, pitch and/or yaw directions.

The propulsion systems may comprise, but is not limited to, propellers, impellers, ducted propellers or pump-jets.

The submersible device or vehicle to which it may be fitted, may be tethered and controlled via an umbilical or controlled remotely using a wireless means such as radio frequency, and may be user-operated or autonomous, or may use combination of both. The suction system, such as a low pressure generating device, as described above, may comprise an educator comprising water jets powered by a pump, which could be an underwater pump powered by the device/vehicle, or by a surface pump via an umbilical.

A video camera may be attached to the device/vehicle, or located separately to the device/vehicle, to allow, for example visual communication between a user and the environment of the aquaculture enclosure. In this manner, the user can control the movement of the device/vehicle in order to locate the dead/diseased and/or dying fish for collection and optional removal. The, or additional camera may also provide information to the user in terms of when the collection means is becoming full. In one embodiment a separate camera is provided so that the interior of the collection means can be viewed. And hence the user can determine when the collection means is becoming full and requires emptying. Alternatively, the camera may be linked to a computer processor with associated software designed to permit automatic identification of dead, diseased and/or dying fish. Thus, a user may not be required and the device/vehicle may be able to manoeuvre itself within the aquaculture enclosure in order to identify and collect appropriate dead, diseased and/or dying fish. Alternatively, other detection means can be employed such as sonar.

In an embodiment, the video camera(s) may employ multi-spectral imagining such as infrared (thermal imaging), or ultra-violet imaging.

In another embodiment, video cameras may be installed on other devices such as the net, additional underwater vehicles, or buoys, to provide third person view of the device.

In another embodiment, a sonar device may be fitted to the device to allow detection of moving live fish and stationary, dead fish. This would allow an operator to target morts or diseased/dying fish without the need for visual communication.

In another embodiment, no visual communication or detection means are employed.

The device/vehicle may be user-controlled via an umbilical or controlled remotely using a wireless means such as radio frequency.

In an embodiment, an autonomous system may be installed allowing the device to target fish/water creatures without human control, for example using a sonar system, or other means of underwater audio or visual detection and a feed-back control, or by simply performing a pre-assigned path or raster scan approach whereby the device methodically traverses the entire net, collecting any morts along its path.

In another embodiment, a combination or user-control and autonomous control may be employed, depending upon the specific conditions and requirements.

In one embodiment, the system may be powered by at least one on-board battery.

In another embodiment, the system may be powered by an external power source provided via an umbilical to the shore, or other surface, such as a boat, ship, buoy, dock or other fish farm platform or apparatus.

In another embodiment, the system may utilise a combination of both an on-board battery power system and external power source via an umbilical.

The umbilical cord may carry some or all required services to and/or from the submersible device/vehicle, including but not limited to, electrical power, data communication, fibre optic communication, video feed, compressed air and water services. In addition, a load carrying cable, chain or rope may be employed alongside, or separate to the umbilical. This may facilitate removal of the submersible device/vehicle should for example power and/or communication be lost to the device/vehicle.

In one embodiment, a central processor system is integrated into the device to perform processing for the device; its duties may comprise receiving user control input, suction device controlling, propulsion system control, video communication and/or lighting. The central processor may be located on-board the device, or it may be separate to the device or located on the surface.

The collection means may comprise a basket, a cage, a net or a bag or any other containment device. The collection means should be porous to water, so as to allow water flowing from the suction means to pass through and out of the collection means. The size of the collection means may be varied depending on the size and/or number of fish/creatures to be collected. The mesh size of the collection means may be varied depending on the size of the fish to be collected, e.g. the desired (or target) fish. Accordingly, undesirable matter which is smaller than the desired (or target) fish can pass through the collection means unimpeded. Undesirable matter may include, for example, juvenile fish, or fry; fish eggs or larvae; shellfish; rocks; stones; silt etc. By such provision, the capacity of the collection means does not become full of undesirable (or non-target) matter and no damage is caused to healthy non-target juvenile fish and/or other smaller water creatures.

In a preferred embodiment, a cage is used as a collection means which has or may have a mesh size of approximately two centimetre square - small enough to collect juvenile and adult fish, such as salmon, yet large enough so as not to impede the flow of water and act as resistance. Alternatively, the size of mesh may be large enough to collect adult fish/water creatures, but permit smaller juvenile fish/water creatures to escape.

In another embodiment, a smaller mesh size is employed to allow the collection of smaller marine life, such as scallops, clams or shrimp.

In another embodiment, a fine meshed bag is employed to allow the collection of very small sized marine life, such as the collection of fish eggs for transfer to environmentally controlled culture tanks for fish husbandry, selective breeding or rearing juvenile fish.

The size of the collection means may be varied depending upon the size of fish/sea creatures to be collected. By such provision, the device can be scaled to collect small sea creates, or very large fish. Alternatively or additionally, the size and capacity of the cage may be varied depending upon then quantity of fish/sea creatures to be collected and the size of the environment or aquaculture enclosure to be serviced. It will be appreciated by persons skilled in the art that when a larger capacity cage is used, the device will need to resurface to empty the collection means less often than that of a device with a smaller capacity cage. By such provision, the device may travel further in a single trip; downtime is reduced and efficiency of use of the device is increased.

It can further be understood by persons skilled in the art that the size of the components, e.g. funnel and collection means can be interchanged and/or configured for a specific application without the requirement to replace the entire submersible device. The collection means may be located inside the device or may be attached to the outside of the device. Thus, the collection means may be removable, or comprise an opening, door or the like to permit removal of collected fish.

The device and/or vehicle may comprise one or more light(s) to assist with visualisation of features including fish within the aquaculture enclosure.

In an embodiment, an underwater lighting system may be installed to improve the visibility for the operator. The lighting system may comprise visual spectrum light of any colour or wavelength.

In another embodiment, the lighting system may comprise multi-spectral lighting such as infra-red or ultra-violet light.

In an embodiment, a buoyancy system is implemented for underwater stability of the device/vehicle. The buoyancy system may be inflated or deflated as required by the user or other means. The buoyancy system may comprise ballast tanks which may be filled with air, or flooded with water, to aid in buoyancy and depth control to rise to the surface, or sink to the required operating depth.

In an embodiment, the buoyancy system may utilise a compressed air source located on the surface.

In another embodiment, the buoyancy system may utilise a compressed air source located on the submersible device/vehicle.

For the avoidance of doubt, any number of the previously described embodiments can be implemented simultaneously or independently.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as described herein without departing from the scope of the invention as broadly described. The present embodiments are therefore to be considered for illustrative purposes and are not restrictive, and are not limited to the extent of that described in the embodiment.

Further features of the invention are described hereinafter and/or are found within the claims appended hereto.

Detailed Description of the Drawings

The present invention will now be further described in detail and with reference to the figures which show:

FIG. 1 shows a detailed view of a collection device of the present invention;

FIG. 2 shows a perspective photograph of an embodiment of a collection device of the present invention including a duct mouth and containment cage.

FIG. 3 shows in schematic operation of the collection device according to FIG.2

Referring to FIG.1 , a collection device (1 ) and associated suction system is shown, which is designed to be attached to the underneath of an underwater vehicle such as an ROV (not shown). The device (1 ) comprises a collection means and suction system.

The collection means is shown in the form of a cage (2), which has a first end (10) and a distal second end (1 1 ). The cage (2) can comprise a hinge or door (not shown) to allow access to the interior of the cage (2) for inspection and/or fish removal. The cage (2) has a mesh structure (9) for the containment of marine life, but permit water to flow through the cage (2).

Attached via the first end (10) of the cage (2) is the suction system, which comprises a ducting tube (3) and associated means to generate low pressure with the ducting tube (3). The suction system comprises a number of jet nozzles (4) which are attached to the tube (3) via an annular attachment device (5). In this embodiment, the tube (3) is 10 inches (254mm) in diameter. The nozzles (4) are fed by a pipe (6) which is also attached to the annular attachment ring (5). The pipe (6) feeds fluid from a pump (not shown) to the jet nozzles (4). In an embodiment, the pump provides fluid at a flow rate of 25 litres per minute and a pressure of 200 PSI (1 .38 MPa).

The ducting tube (3) has a fitting for multiple attachments (7) at the end distal to the end attached to the cage (2). A camera (8) is attached to the ROV via an attachment device (not shown), to allow visual communication between an operator and the underwater environment of an aquaculture enclosure.

FIG. 2 shows an embodiment of the device (1 ) as represented in Figure 1 , showing a funnel (12) attached to the ducting tube (3). As shown the funnel (12), has a large opening designed to permit easy entrainment of fish into the device (1 ) and subsequently into the ducting tube (3) and finally into the cage (2).

FIG. 3 shows the operation of the device according to FIG. 2 in which an operator (22) controls a submersible vehicle (27) to which is attached the device as shown in FIG. 2. The submersible vehicle (27), as attached to the device is shown within a fish farm enclosure (20) below the surface of the water (21 ). Any suitable submersible vehicle may be used, examples of which include Seaeye ROVs manufactured by SAAB or predator ROVs manufactured by Seatronics. The operator (22) uses a control unit (23) connected to the submersible vehicle (27) by an umbilical (25). The operator can view a video feed from the camera (not shown) on a visual display unit (24) in order to view the water in front of the device and any fish which may be present. In this manner a user is able to discern whether or not any particular fish is healthy and should be left alone, or is diseased/dying/dead and should be collected using the device. The submersible vehicle is attached to a surface body via a tether (26).

The operator (22) manoeuvres the submersible vehicle (27) using propulsion means of the vehicle (27), towards a mort (28) by viewing the visual display unit (24) and appropriate directional controls on the control unit (23). When the submersible vehicle (27) is in close proximity of the mort (28), the operator (22) engages the suction system (not shown) of the device (1 ), which induces a flow of water through the duct mouth (12), entraining the mort (28) and directing it through the ducting to the containment means (not shown).

In initial trials, the funnel and cage were sized and configured for the collection of 1 -2 kg fish and it was found that the cage was capable of holding up to 100 fish.

In subsequent developments, the size of the funnel and cage were increased to allow the collection of up to 10kg fish and it was found that the enlarged cage was capable of holding up to 50 fish.

Accordingly, the person skilled in the art will understand that complete customisation can be achieved with the proposed invention, simply by altering the size of the funnel and cage.

Claims

1 . A method for collecting fish and/or other water creatures from an aquaculture enclosure, the method comprising: providing to the aquaculture enclosure a submersible device for collecting the fish and/or other water creatures; controlling movement of the submersible device in three-dimensions within and around the body of water of the aquaculture enclosure, in order to specifically manoeuvre the submersible device towards a desired fish and/or other water creature floating within the body of water; and using a suction system of the submersible device for collecting the desired fish and/or other water creature in a porous collection means which is configured to permit water and undesirable materials to pass through the collection means.

2. The method according to claim 1 wherein the submersible device is manoeuvrable by way of a propulsion means which controls the three-dimensional movement of the device allowing it to manoeuvre itself to any point within the aquaculture enclosure.

3. The method according to claim 1 or 2 for the collection and optional removal of dead, diseased and/or dying fish and/or water creatures from the aquaculture enclosure.

4. The method according to any preceding claim wherein the fish are salmon.

5. A submersible device for collecting the fish and/or other water creatures, the submersible device comprising: a suction system designed to enable collection of fish from an aquaculture enclosure and porous collection means to contain the collected fish until their removal from the device, the porous collection means being configured to permit water and undesirable materials to pass through the collection means .

6. The submersible device according to claim 5 comprising propulsion means which control movement of the device in three-dimensions allowing the device to be manoeuvred to any point within an aquaculture enclosure.

7. The submersible device according to claim 5, wherein the submersible device is designed to be retrofitted/attached to an underwater vehicle and the underwater vehicle comprises propulsion means which controls the three-dimensional movement of the vehicle allowing the vehicle to be manoeuvred to any point within an aquaculture enclosure.

8. An underwater vehicle comprising a submersible device according to claim 5 and propulsion means which controls the three-dimensional movement of the device allowing the vehicle to be manoeuvred to any point within an aquaculture enclosure.

9. The method, submersible device or underwater vehicle according to any preceding claim, wherein the suction system comprises an eductor powered by water jets.

10. The method, submersible device or underwater vehicle according to claim 9 wherein the water jets are fed by a subsea pump.

1 1 . The method, submersible device or underwater vehicle according to claim 10 wherein the water jets are fed by a surface pump.

12. The method, submersible device or underwater vehicle according to any preceding claim wherein the fish are collected in a basket, a cage, a net or a bag.

13. The method, submersible device or underwater vehicle according to any preceding claim wherein the controlled movement is autonomous or user controlled, or comprises a combination of both.

14. The method, submersible device or underwater vehicle according to any preceding claim wherein the movement is controlled via an umbilical or wireless controlling means such as radio signal or sonar.

15. The method, submersible device or underwater vehicle according to any preceding claim wherein the device or vehicle comprises an umbilical cord or cords carrying required services which may comprise electrical power supply, video feed, compressed air and/or water supply.

16. The method, submersible device or underwater vehicle according to any preceding claim wherein the device or vehicle comprises a tether.

17. The method, submersible device or underwater vehicle according to any preceding claim wherein the device or vehicle comprises a camera to facilitate identification of the fish and/or other structures/features within the aquaculture enclosure.