HK1183765B - Device for holding and positioning equipment at - and method for feeding fish in - a cage - Google Patents

Description

Device for holding and positioning equipment at a cage and method for feeding fish in a cage

Technical Field

The invention relates to a fish cage for fish farming, mainly salmon farming. More particularly, the invention relates to a device for holding and positioning equipment at a fish cage having a substantially circular cross-section, and also to a method of feeding fish using said device.

Background

In general, fish in a fish cage are fed by means of a feed dispenser centrally arranged in the cage, preferably with automatically timed feeding time intervals, and this is remotely controlled. The monitoring camera is preferably arranged in the fish cage so that the operator can monitor all situations and visually determine the extent to which the fish eat.

When there is a water flow in the water and possibly a wind, part of the feed may float and/or blow out of the fish cage from the side and be lost through the side walls of the fish cage in the direction of the water flow and/or wind. The extent to which this actually occurs will vary with the environment and the position of the fish cage in the ocean.

The smallest fish that have recently been transferred from the smaller boxes to the fish cage will swim along the periphery of the fish cage for a period of time and rarely swim towards the center of the fish cage. These smallest fish rarely receive feed from the dispenser and are usually fed by hand by the operator, wherein feed is manually sprinkled to each cage several times per day. This requires a significant amount of labor and is a risky job in inclement weather conditions.

It is necessary to frequently inspect the seine to detect possible damage that would cause fish to escape, which would be difficult to perform if a diver were not employed for inspection.

A bird net is arranged above the fish cage so that birds (especially carnivores) cannot access the fish cage. According to a known solution, the bird net is extended from a central "tower" floating in the fish cage. Such a tower comes into conflict with the feed dispenser that is most central in the fish cage, which means that neither the tower nor the feed dispenser can achieve an optimal position. In practice this means that parts of the bird net are immersed in the water, which may injure the fish. In addition, the tower is an obstacle for the feed from the feed dispenser, which means that the feed is not only not spread in an optimal way, but also some of the feed is crushed and not eaten.

This work usually requires the use of specially equipped Remotely Operated Vehicles (ROVs) remotely controlled from the surface when cleaning the fish cage. This operation can disturb the fish and is rather expensive. It would be a great advantage if the use of expensive equipment that has to be brought into and temporarily placed in the fish cage for cleaning the wall(s) and bottom of the fish cage could be avoided.

Disclosure of Invention

Purpose(s) to

It is therefore an object of the present invention to provide an apparatus which simplifies the operation of fish cages and reduces the required labour time, which apparatus improves safety and improves the welfare of fish.

Another object is to provide an apparatus which reduces feed losses, thereby improving the economy of operation of the fish cage, while at the same time avoiding undesired feeding of wild fish.

A further object is to provide an apparatus which simplifies the control for preventing damage to the seine to detect early the risk of fish escaping the cage.

The invention

The above object is achieved by the device for holding and positioning equipment at a fish cage of the present invention. The fish cage has a substantially circular horizontal cross section and comprises a seine and at least one floating ring, the seine being attached directly or indirectly to the floating ring, characterized in that the device comprises a cross beam arranged radially across the fish cage, the cross beam comprising at each end a support structure equipped with wheels that run on rails arranged on the floating ring of the fish cage, the cross beam being pivotally arranged above the fish cage by simultaneous movement of the support structure along the rails, the cross beam being provided with automatically adjustable support arms to compensate for deviations of the fish cage from a perfect circular shape when the cross beam is rotated.

Preferably, the track forms a continuous track on the buoyant ring and the transom comprises two support structures arranged to stand diametrically opposite each other on the buoyant ring, each support structure comprising at least two wheels, the transom further comprising a lattice structure whose function is to provide strength to the transom, thereby allowing the transom to extend over the fish cage without substantial sag.

Preferably, the fish cage comprises an inner buoyant ring to which the seine is attached and an outer buoyant ring attached to the inner buoyant ring.

Preferably, the track extends substantially continuously along the outer buoyant ring.

Preferably, the cross-beams comprise a lattice of light metal, which lattice is provided with attachments for the desired equipment.

Preferably, the inner and outer buoyant rings are interconnected by a connecting means, and the track supporting the wheels of the two support structures is attached to a reinforcing attachment above the outer buoyant ring.

Preferably, said cross-beam is arranged to be rotated by a motor driving at least one said wheel on each said support structure.

Preferably, the cross beam is provided with a bracket for the feed dispenser, the bracket having a pivotally attached flap that allows the feed dispenser to be oriented independently of the orientation of the cross beam.

Preferably, the support for the feed dispenser is arranged to be moved to any desired position along the cross beam by means of a support motor and a drive gear, the supply hose supplying feed to the feed dispenser being arranged in a roll outside the fish cage.

Preferably, the roll is adapted to the size of the fish cage, if required, and a special supply hose motor is arranged to assist pushing out and pulling in the supply hose for feed.

Preferably, the crossbar has an attachment for an underwater camera that is movable by a camera motor and drive gear in a manner that is independent of the positioning and movement of the feed dispenser.

Preferably, the cross beam has an attachment and a motor for at least one cleaning device arranged to clean the seine of the fish cage.

Preferably, the crossbar is arranged via a pivot attachment to support a central portion of a bird net support arranged above and radially outward of the crossbar of the support structure including the crossbar.

Preferably, automatic length adjustment of the support structure is achieved by a telescopically extendable arm.

Preferably, the track is formed by at least 1 metre long straight track sections hinged together, the angle between two adjacent straight track sections being between 160 and 190 degrees.

Preferably, the cross beam has an attachment for a surface camera arranged to be moved by the motor and drive gear independently of the position and movement of the feed dispenser.

Preferably, the cross beam has an attachment for a surface camera that can follow the position and movement of the feed dispenser.

Preferably, the traction wire is arranged to allow the traction wire to correct tightness at all times independently of varying degrees of ovality of the fish cage by means of an automatically adjustable pull attachment connected to a sliding friction gear and a motor.

According to another aspect, the invention relates to a method for feeding fish in a fish cage having a circular cross-section using a feed dispenser that throws feed pellets in a circle from the position of the feed dispenser, characterized in that the feed dispenser is arranged to move linearly on a pivoting beam extending radially above the fish cage, determining the current flow direction in the water, the beam is rotated to a position parallel to the current flow direction in the water, and if desired, the feed dispenser is moved along the beam to a position where an underwater camera can confirm that the feed pellets are not carried out of the fish cage by the flowing water.

In the above method, the flow direction is preferably determined by an underwater camera suspended from the beam.

In the above method, preferably, the feed dispenser is moved to a more upstream position if an underwater camera indicates that the feed pellets are carried out of the seine of the fish cage.

In the above method, preferably, the current wind direction is determined by a surface camera, and the beam is arranged by rotation in a direction parallel to the current wind direction, and if necessary, the feed dispenser is moved along the beam to a position where the underwater camera and the surface camera can confirm that the wind does not carry the feed pellets out of the fish cage.

The present invention has several advantages over the prior art in this field. One of the main advantages is that a higher degree of control over feeding is enabled, so that loss of feed can be eliminated or significantly reduced. The invention also allows for local feeding near the wall of the fish cage without requiring personnel to manually feed on site, since the feed dispenser can be positioned anywhere above the fish cage. Moreover, since the frame supports the bird net and the frame is supported centrally by the cross beam, conflicts between the bird net tower and the feed dispenser can be completely eliminated, so that the bird net is positioned above the cross beam over the entire fish cage, while the feed dispenser is suspended from and positioned below the cross beam. Another advantage is that the device for cleaning the fish cage can be suspended on the cross beam and controlled such that the side walls as well as the bottom wall of the seine of the fish cage can be reached through the device for cleaning the fish cage. Thus, a remotely operated vehicle for cleaning is no longer required. The individual fish farm owner decides whether to arrange the cleaning equipment permanently in each cage or to move it from one cage to another.

Furthermore, by moving the camera around in the fish cage, the camera will allow monitoring of the state of the seine and detection of cracks in the seine, allowing action to be taken to prevent fish from escaping.

Drawings

The invention and its method of use will be described in more detail hereinafter with reference to the accompanying drawings, in which:

FIG. 1 is a schematic top view of a fish cage incorporating the present invention;

FIG. 2 schematically shows a side view of the support structure as seen along a radius of the fish cage;

FIG. 3 is a schematic side sectional view of certain components of the apparatus of the present invention;

FIG. 4 is a side cross-sectional view of a plurality of components according to the present invention;

FIG. 5 shows an enlarged cross-section of certain components of a device according to the invention;

FIG. 6 is a schematic top view of other elements of the device according to the invention;

fig. 7 schematically shows some other elements of the device according to the invention.

Detailed Description

Fig. 1 is a top view of a fish cage 1 having a generally circular horizontal cross-section. As shown in the figures, the fish cage is slightly oval, which may also be a box for fish cages placed in the sea during weather changes. The cross beam 2 is arranged across or radially on the fish cage and ends at both ends in support structures 10 and 11, respectively. The support structures 10, 11 are arranged to travel on a track 3 (indicated with dashed lines), said track 3 being arranged in series along the outer buoyant ring 7. The fish cage further comprises an inner floating ring 6, said inner floating ring 6 holding a seine 8 constituting the side and bottom walls of the fish cage. The two floating rings 6 and 7 are connected together and dimensioned such that said floating rings 6 and 7 provide a good and sufficient buoyancy under all conditions. The use of two floating rings joined together is not a unique element of the present invention.

It should be emphasized that the dimensional relationships between elements in the drawings may be severely distorted compared to reality. The distance between the inner buoyant ring 6 and the outer buoyant ring 7 is therefore no more than a few metres, whereas the diameter of the generally circular area defined by the inner buoyant ring is typically 50 metres.

The feed dispenser 4 is suspended at the lower side of the cross beam, said feed dispenser 4 being arranged to be moved along the cross beam 2 over substantially the entire extension of the cross beam 2 by means of the feed dispenser bracket 39 and the motor 13. The feed dispenser 4 is connected to a supply hose 28 for periodic supply of feed.

Suspended from the cross beam 2 is an underwater camera 5 which can be driven by a separate motor 61 to move along the cross beam 2 independently of the movement and position of the feed dispenser 4. Thus, the underwater camera 5 may be positioned near the feed dispenser or remotely from the feed dispenser, as desired. It will be understood that if not specifically mentioned, when the motor is positioned at a distance from the element it is intended to drive, a traction wire is usually provided between said motor and the element (being the feed dispenser, the camera or other equipment). As an alternative to a pull wire, the motor can be connected directly to the feed dispenser, camera or other device. The underwater camera can be connected to the terminal enclosure via a cable up the bottom of the fish cage.

Fig. 1 also shows a surface camera 31 which, like the suspension for underwater cameras, can be driven along the beam by a separate motor 49. Alternatively, the surface camera may be permanently mounted on the feed dispenser 4, which simplifies the construction to some extent but reduces the freedom of movement accordingly.

The cross beams 2, including the support structures 10 and 11, constitute a bridge which extends radially all the way over the fish cage 1, the height of which is well above the upper points of attachment of the seine 8 and the rails. The cross beam is enabled to rotate above the fish cage when required by allowing the support structures 10, 11 resting on the wheels 26 to be controlled to travel equal distances by means of at least one motor 9. The left side of fig. 1 shows that the cross beam can be extended or retracted by a telescopic function, wherein one inner arm rigidly attached to the support structure 11 is received within an outer arm rigidly attached to the support structure 10. Also shown in fig. 1 is a preferably pivoting tray 51 attached to the upper side of the beam 2 for the purpose of supporting the bird net support as described below.

Fig. 1 also shows: a supply drum 30, said supply drum 30 being for pulling a supply hose 28 over said supply drum 30; a motor 42, said motor 42 for moving a cleaning tool or other tool; a traction motor 44, the traction motor 44 having a braking function for a traction wire 46; a motor 49, the motor 49 for moving the surface camera; and a connecting device 68 for a fish cage.

Fig. 2 schematically shows a side view of the support structure 10, 11 seen along a radius of the fish cage 1. In the shown embodiment the support structure 10, 11 has two wheels supported on rails, one at each end of the support structure. In addition, the support structure has two "grippers" 21 integrated with the wheels 26, said grippers 21 being designed to prevent any upward movement of the support structure 10, 11 due to external influences. The clamp may be in the form of a claw which, when the track 3 has a T-shaped profile, grips around and under a "flange" of the track 3. The interface of the cross beam that extends into the plane of the paper (along the radius of the fish cage) is shown in the upper part of fig. 2, and also shows the balls 58, which balls 58 allow pulling the arms 29 of the cross beam 2 out of the outer arms of the cross beam. In fig. 2, the scraping member 20 for removing ice and other possible foreign bodies on the rail 3 is shown in front of the wheel 26. The motor 9 shown in fig. 2 is a motor for moving/rotating the cross beam 2.

The safety chain 53 is arranged to be connected to the transverse beam comprising the support structure 10, 11 and is fixed to the rail 3 by means of the safety clamp 21 as an additional safety measure in extreme conditions (e.g. external influences in the form of collisions or the like), so that the transverse beam can be prevented from falling into the fish cage, even in the unlikely event of a breakage of the transverse beam.

Thus, referring to FIG. 3, an enlarged wheel 26 is shown. The clamp 21 in fig. 3 is further provided with a horizontal stop 72, said stop 72 being positioned below the substantially horizontal part of the T-shaped rail 3. The wheels 26 and the T-shaped portion of the track 3 are shown as having suitably curved surfaces which provide optimal contact between the wheels and the track when the waves alternately raise and lower different sides of the fish cage. Figure 3 also shows the axle 60 and the reinforcing attachments 22, said reinforcing attachments 22 serving to distribute the weight from the rail 3, so that the inner and outer buoyant rings 7 help to support the weight applied to the rail 3 by the cross beam 2. The distance wires 15 ensure that the support structures 10, 11 are always equally spaced apart as measured along the outer circumference (circumference) of the fish cage 1.

The movable connection joint 27 and the use of the connection bolt 69 allow the track 3 to always be able to accommodate the movement of the floating rings 6 and 7 of the fish cage 1. The connecting device 68 forms a platform that allows the device to be used on most existing types of fish cages.

The invention is not limited to a particular size and it is also common for the fish cage to have a diameter of 50 metres and in this size the distance between the outer wheels 26 of the support structure may be 7 metres to provide sufficient stability.

With said dimensions, a certain angular difference between the two wheels 26 is required to enable good running of the wheels 26 on the track. In this position and orientation, the wheels 26 will rotate with an axis parallel to the radius of the fish cage at the location of each wheel.

Fig. 4 again shows, in a simplified manner, a side sectional view of a part of the crossbar 2, said part of the crossbar 2 comprising a support structure 10 as seen along the periphery of the fish cage 1 (i.e. perpendicular to the view of fig. 2). The inner and outer buoyant rings 6, 7 are each shown as rings having a circular cross-section. These are physically connected to a solid connection means 68, said connection means 68 comprising a reinforcing appendix 22, said reinforcing appendix 22 being intended to also serve as a base for the rails 3 supporting the support structure 10, 11. The attachment 22 has a counterpart in the form of a reinforcing clip 24 mounted from below. A stronger connection than normal is thus obtained between the inner and outer rings, the purpose of which is to ensure that the extra weight from the cross beam is distributed between the two floating rings, instead of being borne by only one floating ring. A handrail 40 is schematically shown connected to the inner buoyant ring for preventing a person working on the fish cage from falling into the sea. The top of the seine 8 is shown attached to a railing 40. Similarly in fig. 2, a wheel 26 is shown surrounded by the clamp 21. The use of an external railing (not shown) in addition to the railing 40 is an obvious option to better protect people against the risk of falling into the sea. Such a handrail can be part of or integrated with the bird net support (frame).

It is important that the base in the form of the appendages 22 of the support rail 3 is strong and stable, since the weight of the cross beam 2, including the support structures 10 and 11, can be between 1500kg and 2000kg, half of the weight of said cross beam 2 being transferred to each of the two opposite sides of the fish cage and then distributed to the wheels used on each support structure (typically two to five wheels). Thus, each wheel will typically carry a weight in the range of 150kg to 500kg, while an area of the track 3 of about 7 metres will have to support a weight of about 750kg to 1000 kg.

Furthermore, fig. 4 shows how the cross beams 2, in addition to comprising telescopically interacting parts, advantageously comprise a lattice structure, the purpose of which is to provide sufficient strength in the transverse direction so that the cross beams do not sag downwards over a large span, represented by the diameter of the fish cage.

Furthermore, fig. 4 shows how a frame in the form of a bird net support 17 is arranged above the crossbeam 2 and radially outside the crossbeam 2 and is supported by the crossbeam 2 via a disc 51 at the centre of the crossbeam. Outside the rail 3, at the floating ring 7, a special lower attachment 25 for the bird net support 17 is provided. Thus, contrary to the solutions of the prior art fish cages, in the present invention there is no conflict between the positioning of the feed dispenser 4 and the support or support for the bird net, since the bird net is substantially above the cross beam 2 and outside the cross beam 2, while the feed dispenser is positioned below the cross beam. Thus, by including a) the angular position (rotation) of the beam on the fish cage; and b) movement of the feed dispenser along the beam (linear) positioning, enabling the feed dispenser 4 to be positioned at any given point at any given time, either centrally within the fish cage or at any point near the periphery of the fish cage.

Cables 37 connected to the control unit 14 can follow the bird net support 17 to the center of the beam if desired. Also shown in fig. 4 is a power supply 23 connected to the control unit.

Fig. 5 shows how the feed dispenser 4 is suspended from the cross beam 2 such that the feed dispenser 4 is pivoted and can move linearly with respect to the cross beam by means of balls 73 and 77. The purpose of the pivoting feed dispenser is to allow it to maintain a substantially fixed orientation relative to the feed supply hose 28 independent of the orientation of the cross beam 2 when the cross beam 2 is rotated. As will be described in more detail below, the meaning of the linear movement is to enable the feed dispenser 4 to be moved to any location on the fish cage depending on weather and flow conditions and depending on the size of the fish to be reared. Fig. 5 also shows (as shown in the previous figures) balls 58, said balls 58 allowing the arms 29 of the cross-beam 2 to be automatically adjusted to achieve the desired function. The outer part of the feed dispenser 4 is located in an engaging piece 74, said engaging piece 74 being arranged to rotate quickly during dispensing of feed to throw said feed into a circular area around the feed dispenser. The pivot disc 75 is an element that together with the engaging member 74 allows the feed dispenser 4 to rotate 360 degrees relative to the bracket 39 of the feed dispenser 4.

An "automatically" adjustable carriage arm is to be understood as a force applied to the crossbar from the support structure 10, 11 in the longitudinal direction of the crossbar, which causes the balls 58 to urge the arms 29 out of or into, respectively, so that no significant force can ever be generated along the crossbar and so that the wheels 26 on the support structure 10, 11 are not pushed out of or pulled out of the track 3 because the fish cage is oval.

Referring now to fig. 6, in order to enable the feed dispenser to move linearly back and forth while connected to the feed supply hose 28, it is desirable to be able to adjust the effective length of the feed supply hose. This can be achieved in several ways, the simplest being to arrange the feed supply hose 28 in a roll 50, typically the roll 50 being placed on some kind of reel, allowing for size variations to be adapted to the size of the fish cage 1, which means that the free length of the feed supply hose 28 between the roll 50 and the feed dispenser 4 is long enough to reach the furthest point in the fish cage 1, measured from the roll, when the roll 50 is at the smallest attainable radius. In addition, when the effective diameter of the roll is increased to the point where it is necessary to move the feed dispenser to the position of the roll 50 closest to the feed supply hose 28 within the fish cage, structure must be provided to support the feed supply hose 28 as necessary. For a fish cage with a diameter of 50 meters, the roll must be able to roll up and pay out almost 50 meters of hose. However, the hose may have several turns on a roll, allowing its outer dimensions to be reduced. If, for example, the feed supply hose has three turns on the reel forming the roll, each turn of the roll needs to be paid out and wound up about 16 meters (3 x 16-48), which changes the diameter of the roll by about 5.1 meters between the poles. A separate motor 41 can be arranged to be connected to the roll so that the motor 13 is used to handle the load related to the feed supply hose 28 without having to change the size of the motor 13 connected to the feed dispenser 4. In fig. 6, a stop point 67 for the movement of the cross beam 2 is also shown.

Fig. 7 shows an element for automatically maintaining the correct pretension of the traction wires independent of whether the fish cage is circular or elliptical. The traction wire is always kept in a tensioned state by a traction wire attachment 48 which can be automatically adjusted, wherein said traction wire attachment 48 is operated by means of the brake gear 45 and the motor 44.

Method of use of a device according to the invention

When starting feeding, the feed dispenser may be positioned centrally in the fish cage 1.

The underwater camera 5 is positioned near the feed dispenser so that the operator can see the dispersion of the feed (compressed feed) in the water. If a significant deviation is detected due to the flow in the water, the beam is rotated so that it becomes parallel to the flow direction. The underwater camera 5 can be moved downstream to allow the operator to see if all the feed is eaten or if some of the feed floats through the seine wall 8 to be consumed. If the flow in the water is strong and in particular if it can be observed that a portion of the feed is lost, the feed dispenser 4 will move further upstream until it is ensured that all feed stays in the fish cage 1 long enough to be eaten in its entirety. In extreme cases, feeding may be terminated. During strong winds, it is more convenient to be able to verify in an optimal way that feeding is carried out without losses using the surface camera 31.

When feeding is performed close to the periphery of the fish cage 1, the feed dispenser is moved to the place where the fish are located, typically as far upstream as possible, without dispensing feed outside the fish cage, and feeding is then performed in said area. Although the feed distribution can be observed within a desired area using the surface camera 31, the underwater camera in combination with the present invention allows for optimal feeding for the flow in the water in each single feeding process.

Cleaning equipment can reach and clean any position of the walls of the seine 8, which is suspended from the transverse beams 2 in such a way that it can move along the beams in the same way as an underwater camera, and which can be raised or lowered. For a certain vertical height of the cleaning apparatus, cleaning of the entire seine can be carried out by nearly 2 rotations of the cross beam 2 by 180 degrees. Thereafter, the cleaning device can be adjusted to a new height and another opposite rotation of the cross beam is performed. In this way, cleaning can be continued until the entire height and periphery of the mantle wall has been cleaned. Alternatively, cleaning may be carried out by: the cleaning apparatus is moved vertically along the periphery at a specific location, then the beam is rotated slightly across the width of the cleaning zone, and then a new vertical movement is made from the bottom to the top of the seine (or vice versa).

By turning the cross beam 2 and moving the cleaning device axially along the cross beam, any given position of the bottom of the fish cage can also be reached and cleaned.

With the help of surface and underwater cameras, the device enables the entire fish cage to be monitored completely remotely according to the principles already explained. As mentioned, this is very important for possible damage of the seine, as it allows measures to be taken to prevent the farmed fish from escaping.

The surface camera 31 can also help to monitor and feed the fish, i.e. so-called surface feeding, by having the surface camera 31 follow the feed dispenser 4 or by moving the camera separately. Therefore, the user can well perceive the appetite of the fish.

In summary, the most important functions and advantages obtained by the present invention are:

i. by reducing the loss of feed, consumption is reduced and thereby a more cost-effective feeding is obtained while at the same time protecting the environment. By always optimizing the positioning of the feed dispenser, fish can be fed effectively wherever they are, especially in the case of small fish that normally stay along the seine wall, away from a conventional centrally mounted feed dispenser.

Allow cleaning of the walls and bottom of the seine without the use of a Remotely Operated Vehicle (ROV).

Allowing complete monitoring of the entire seine for damage thereby preventing fish from escaping.

The device according to the invention also enables optimal surface feeding by allowing the surface camera 31 and the underwater camera 5 to follow the feed dispenser 4 and to be positioned above and below the feeding point regardless of the position of the feed dispenser 4 in the fish cage. Thus, the appetite of the fish can be visually evaluated, so that the accuracy of the feeding process can be further improved. The surface camera can be arranged to always follow the feed dispenser, if desired; the feed dispenser and the surface camera can even share accessories.

Claims (22)

1. A device for holding and positioning equipment at a fish cage (1) having a substantially circular horizontal cross-section, and comprising a seine (8) and at least one floating ring, to which the seine is attached directly or indirectly, characterized in that it comprises a cross-member (2) arranged radially across the fish cage (1), the cross-beam comprises at each end a support structure (10, 11) equipped with wheels (26), the wheels running on rails (3) arranged on the floating ring of the fish cage (1), the cross beam (2) being pivotally arranged above the fish cage (1) by simultaneous movement of the support structures (10, 11) along the track (3), the cross beam (2) being provided with an automatically adjustable arm (29), to compensate for deviations of the fish cage (1) from a perfect circular shape when the cross beam (2) is rotated.

2. The device according to claim 1, characterized in that the track (3) forms a continuous track on the buoyant ring, and the crossbeam (2) comprises two support structures (10, 11) arranged to stand diametrically opposite each other on the buoyant ring, each support structure comprising at least two wheels (26), the crossbeam further comprising a lattice structure, the function of which is to provide strength to the crossbeam, allowing it to extend over the fish cage without substantial sag downwards.

3. The device according to claim 1, characterized in that the fish cage comprises an inner buoyant ring (6) and an outer buoyant ring (7) attached to the inner buoyant ring, the seine (8) being attached to the inner buoyant ring (6).

4. A device according to claim 3, characterized in that the track (3) extends substantially continuously along the outer buoyant ring (7).

5. The device according to claim 1, characterized in that the cross beams (2) comprise a lattice of light metal provided with attachments for desired equipment.

6. A device according to claim 3, characterized in that the cross beam (2) comprises two support structures (10, 11) arranged to stand on the buoyant ring diametrically opposite each other, that the inner buoyant ring (6) and the outer buoyant ring (7) are interconnected by connecting means, and that the track (3) supporting the wheels (26) of the two support structures (10, 11) is attached to a reinforcing attachment above the outer buoyant ring (7).

7. Device according to claim 1, characterized in that the cross-beam (2) is arranged to be rotated by a motor (9) driving at least one of the wheels (26) on each of the support structures (10, 11).

8. Device according to claim 1, characterized in that the cross beam (2) is provided with a bracket (39) for the feed dispenser (4), which bracket (39) has a pivotally attached flap which allows the feed dispenser (4) to be oriented independently of the orientation of the cross beam (2).

9. Device according to claim 8, characterized in that the carriage (39) for the feed dispenser (4) is arranged to be moved to any desired position along the cross beam (2) by means of a carriage motor (13) and a driving gear, and that the supply hose (28) supplying feed to the feed dispenser (4) is arranged as a roll (50) outside the fish cage (1).

10. Device according to claim 9, characterized in that the roll (50) is adapted to the dimensions of the fish cage (1) and that a special supply hose motor (41) is arranged to assist pushing out and pulling in a supply hose (28) for feed.

11. Device according to claim 9, characterized in that the crossbar (2) has an attachment for an underwater camera (5) which can be moved by a camera motor (61) and a drive gear independently of the positioning and movement of the feed dispenser (4).

12. Device according to claim 1, characterized in that the cross beam (2) has an attachment and a motor (42) for at least one cleaning device arranged to clean the seine (8) of the fish cage (1).

13. The device according to claim 1, characterized in that the crossbar (2) is arranged via a pivot attachment to support a central portion of a bird net support (17), the bird net support (17) being arranged above and radially outside the crossbar (2) of the support structure (10, 11) comprising the crossbar (2).

14. Device according to claim 1, characterized in that automatic length adjustment of the support structure (11) is achieved by means of a telescopically extendable arm (29).

15. Device according to claim 1, characterized in that the track (3) is made up of at least 1 meter long straight track sections hinged together, the angle between two adjacent straight track sections being between 160 and 190 degrees.

16. Device according to claim 1, characterized in that the cross beam (2) is provided with a bracket (39) for the feed dispenser (4), the cross beam (2) having an attachment for a surface camera (31) arranged to be moved by means of a motor (49) and a drive gear independently of the position and movement of the feed dispenser (4).

17. Device according to claim 1, characterized in that the cross beam (2) is provided with a bracket (39) for the feed dispenser (4), the cross beam (2) having an attachment for a surface camera (31) that can follow the position and movement of the feed dispenser (4).

18. Device according to claim 1, characterized in that the traction wires are arranged to allow the traction wires to always correct tightness in a way independent of varying degrees of ovality of the fish cage by means of automatically adjustable pull attachments connected to sliding friction gears and motors (44).

19. A method for feeding fish in a fish cage (1) with a feed dispenser (4) having a circular cross-section, which in a circular manner throws feed pellets from the position of the feed dispenser (4), characterized in that the feed dispenser (4) is arranged to move linearly on a pivoting beam (2) extending radially above the fish cage (1), determining the current flow direction in the water, the beam (2) being rotated to a position parallel to the current flow direction in the water, the feed dispenser (4) being moved along the beam (2) to a position where an underwater camera (5) can confirm that the feed pellets are not carried out of the fish cage by the flowing water.

20. Method according to claim 19, characterized in that the flow direction is determined by means of an underwater camera (5) suspended from the cross beam (2).

21. Method according to claim 19, characterized in that the feed dispenser (4) is moved to a more upstream position if an underwater camera (5) indicates that the feed pellets are brought out of the seine (8) of the fish cage (1).

22. Method according to claim 19, characterized in that the current wind direction is determined by a surface camera (31) and that the cross beam (2) is arranged by rotation in a direction parallel to the current wind direction and that the feed dispenser (4) is moved along the cross beam to a position where the underwater camera (5) and the surface camera (31) can confirm that wind does not carry feed pellets out of the fish cage.