A floating fish cage construction with lice skirt

Abstract

A floating fish cage construction (10), where the cage construction (10) comprises a floating collar (14) that floats in a body of water (16) and a cage (12) with a lower part (12a) equipped with an impermeable wall and at least one partially open main part surrounded by a lice skirt (18), the main part of the cage (12) being arranged for 5 receiving water to form a main volume of water. The lower part (12a) of the cage (12) comprises a water inlet (20) for supplying water to a volume of water in said lower part (12a), where water is obtained from surrounding or deeper water depths outside a lower part of the main part of the cage (12) or the lower part (12a), the water supplied to the water volume in the lower part (12a) has higher mass density than 0 the water that flows through said at least partially open main part and into the water volume in the main part of the cage (12).

Description

[0001] A floating fish cage construction with lice skirt

[0002] Field of the invention

[0003] The present invention relates to a floating fish cage construction, where the cage construction comprises a floating collar that floats in a body of water and a cage with a lower part equipped with an impermeable wall and an at least partially open main part surrounded by a lice skirt, the main part of the cage being arranged for receiving of water to form a main water volume.

[0004] The background of the invention

[0005] Today's closed or semi-closed cages often consist of an impermeable canvas bag, but can also be made of solid material, often with a cylindrical upper part with a tapered lower part. The lower part can be made of solid material, but often a canvas bag is also used here. The shape does not have to be cylindrical in the upper part. It can also be oval, rectangular etc.

[0006] There are several known technologies for this, and all known technologies need a lot of electricity to drive pumps which in turn will ensure sufficient water flow through the cage so that satisfactory fish welfare is maintained. The lower conical part, either of solid material or impermeable canvas material, ensures efficient collection of waste (mainly food and feces) from the cage.

[0007] Lice skirts are often used in today's open fish cages. This is usually a canvas that can be impermeable or permeable. The canvas is placed outside the net and down to a certain depth to prevent lice larvae and lice from entering the cage. Typically, such a lice skirt ends at a depth of 5-15 m as few lice larvae and lice are found at deeper depths. Unfortunately, it is typical for permeable skirts that they experience marine growth and prevent water from entering the cage. Today, cages with lice skirts often have one or more pumps inside the cage that provide extra fresh water into the cage. These pumps draw water from a level below the lice skirt, but above the bottom of the net. The suction pipe of the pump is inside the net and the pump is usually floating in the center of the cage or at a distance below the water surface. If the lice skirt is impermeable or has significant marine growth together with little natural external water current in the locality, there is a high probability that the water these pumps supply to the fish is of poor quality, at least from a fish welfare point of view. CO2 rich water with feces may be at risk of being recycled within the net with correspondingly poor fish welfare. The water supplied by the pump is often heavier (having higher mass density) than the water surrounding the skirt where the water is introduced. This creates some hydrostatic pressure differences locally with corresponding possible deformation of the skirt.

[0008] Today's typical lice skirt design around the net does not allow for the collection of waste from the cage as it is open at the bottom.

[0009] The lice skirt is often placed loosely around the net, often with weights, which can be a sewn-in chain or weights at the bottom of the skirt to help keep it in place. But experience and tests show that the skirt deforms strongly in bad weather and can also deform the geometry and volume of the net. This is mainly because it is practically hard to make the weights heavy enough to counteract the forces of external water currents. This can mean that the volume of the cage is reduced with reduced fish welfare as a result. In such cases, lice larvae and lice can find their way into the net as the skirt in this condition no longer forms a tight barrier against water that contains these. The skirt can be lifted, and water can be forced into the net. If the skirt is only laid around the net with an overlap and not with a tight connection, then water can be forced into the net by going between the lice skirt where it is overlapped.

[0010] WO2022240296A1 relates to a floating cage for farming fish, which cage comprises a waterproof outer wall and a nearly waterproof outer wall. The outer wall is dimensionally stable. The cage further comprises an inlet for water into the cage and an outlet for water out of the cage at a lower part, and buoyancy means. The inlet for water is located at the top or bottom of the cage, and water is preferably obtained from an area below the cage, but it is also mentioned that the outer wall can be equipped with hatches for the inlet of water.

[0011] WO 2022265515 A1 describes a semi-closed or closed cage construction comprising an external flexible canvas bag suspended in a floating collar where fresh water is sucked in by a number of lines connected to the floating collar.

[0012] Objects of the present invention

[0013] The invention aims to solve many of the above-mentioned challenges and is solved in the following way: To keep the lice skirt, permeable or not, stretched and in the correct position to avoid deformation, the bottom section of the cage is equipped with a dedicated volume of heavier water. This volume can have solid walls, such as glass fibres, GRP (Glass- Reinforced Plastic), or be made of impermeable canvas bag material. The bottom section is connected to the flotation collar with rope, wire or can be connected directly to the flotation collar via the lice skirt if the strength of the skirt can support the weight of the bottom section. Depending on how deep one wants the lice skirt to extend, the skirt ends at the chosen level and is connected to the suspension ropes.

[0014] Water is supplied to this volume from a water depth which makes the water inside this volume heavier than the surrounding water displaced by the same volume. Basically, the mass density of the water inside the volume is higher than the density of the water surrounding the volume. This will pull the lice skirt down and keep it in the correct position and shape even in severe weather conditions. This volume will typically lie around the conical bottom part of the cage and can also be effectively used to collect waste from the cage. Depending on the location's weather conditions, additional anchoring of the skirt can be connected to the existing frame mooring.

[0015] Water from an area of heavier water than on the outside of the surrounding area of the cage is filled into the impermeable bottom section so that the weight of the water inside the bottom section is greater than the weight of the surrounding water which it displaces. To avoid poor quality of this water, one can choose to replace it sporadically or have a continuous inflow and outflow. An outlet for this heavier water can then be placed above the inlet of such heavier water such that heavier water can freely flow in and out. If one wants to fill the entire lower part with water, one can choose to exclude a dedicated outlet and let the water flow over the upper edge of the bottom section instead.

[0016] Depending on the location and weather conditions, one can choose to make the section with heavier water larger or smaller. For example, one can choose to extend it vertically upwards to also encircle the typical cylindrical part of a cage or net. But in such cases, one should be careful with the water quality inside where the fish stay.

[0017] Depending on the lice skirt's possibility to let surrounding water flow pass through it, in some cases one wants to add more water to the cage to maintain good fish welfare. This is particularly important if the lice skirt is impermeable and is not originally designed for water flowing through the fabric. If the lice skirt is initially of a permeable type, a separate water supply can possibly be avoided, but experience suggests that the skirt can be clogged by e.g. marine growth and that the possibility of water supply is appropriate.

[0018] Water can be obtained from surrounding water layers to ensure better quality of the water supplied to the cage. One can imagine that the external water supply is gradually increased as the lice skirt becomes clogged by growth. Where current technology typically has a pump in the center of the cage that sucks up and possibly recycles large amounts of contaminated water, the invention typically has a set of pumps external to the cage that can gradually be put into operation and constantly increase the supply of fresh water from areas outside the cage. Fresh in the sense that it is free from feces, rich in oxygen content and low CO2 content compared to the water present inside and in the bottom of the cage.

[0019] Summary of the invention

[0020] According to the invention, a floating fish cage construction is provided, where the cage construction comprises a floating collar that floats in a body of water and a cage with a lower part equipped with an impermeable wall and an at least partially open main part surrounded by a lice skirt, the main part of the cage being arranged for receiving water to form a main volume of water, the lower part of the cage comprises a water inlet for supplying water to a volume of water in said lower part, where water is obtained from surrounding or deeper water depths outside a lower part of the main part of the cage or the lower impermeable part, the water supplied to the water volume in the lower part having a higher mass density than the water that flows through said at least partially open main part and into the water volume in the main part of the cage.

[0021] The lower part of the cage can include one or more water outlets.

[0022] The lower part can be made of impermeable canvas, i.e. the wall can be a canvas.

[0023] Furthermore, the lower part of the cage can be suspended with a bottom ring, the bottom ring is attached to a lower part of the lice skirt and an upper part of the lice skirt is attached to the floating collar.

[0024] The lower part of the cage can be suspended in the bottom ring, as the bottom ring is suspended using suspension ropes that run from the floating collar. The cage can also comprise a mooring ring arranged in an area between the bottom ring and the floating collar, in which the suspension rope runs from the floating collar to the mooring ring and then on to the bottom ring.

[0025] The main part of the cage can include at least one water inlet for supplying water to the water volume in said main part of the cage, as water is taken from different water depths outside the cage.

[0026] The water inlet for supplying water to the main part of the cage can run through the lice skirt.

[0027] The lice skirt to be used can be a fluid permeable skirt or an impermeable skirt.

[0028] In one embodiment, parts of the main part of the cage may comprise a impermeable canvas, which impermeable canvas runs from the lower part upwards into the main body of water.

[0029] The water volume in the impermeable canvas in the main part of the cage can be filled with similar water having a higher mass density as supplied in the water volume in the lower part of the cage.

[0030] The lice skirt can extend down into the water mass to an area between the floating collar and the bottom ring.

[0031] The lice skirt can extend down into the water mass to a mooring ring arranged in an area between the bottom ring and the floating collar.

[0032] The lice skirt can also extend down into the water mass to an area below the bottom ring.

[0033] Said impermeable canvas in the main part of the cage can include a water outlet.

[0034] The lice skirt can also include a water outlet.

[0035] The lower part of the cage can have a tapered and conical chamfer.

[0036] Alternatively, the lower part of the cage can have a circular cylindrical shape. Furthermore, the cage may comprise one or more partially open or closed canvas bags designed to accommodate a water volume of water having a higher mass density than surrounding water, said canvas bag (s) forming the lower part.

[0037] By “heavier water” is meant water with higher mass density than water higher up in the body of water. Mass density of water increases with increasing water depths. Hence, the mass density of water at the surface is lowest. For the avoidance of doubt the mass density can also be referred to as volumetric mass density or simply as density, and it is a substance's mass per unit of volume. Heavier water can hence refer to water having a higher mass density. ’’Heavier water” is the water that is routed to the volume in the lower part. This water has a higher mass density than the water surrounding the same volume.

[0038] By “impermeable canvas” is meant a fabric or material being impermeable or almost impermeable.

[0039] The invention will also work as intended if the material of the walls in the lower or middle part is made of a permeable material with very low permeability. It then becomes a question of adding more water with high density (higher density than surrounding water) to the lower part such that the volume continues to be stretched out. Basically, maintaining its intended shape and near maximum available volume. If too little water is routed to the lower part having somewhat permeable walls, water will leak out through the fabric and the volume in the lower part will deflate. Water will leak out because the water inside the lower part has a higher mass density than the water outside the lower part. This can be solved by adding so much water to the lower part that less than 100% of the water supplied can pass through the fabric. The excess water hence has to escape out through the intended outlets discussed.

[0040] Description of figures

[0041] Preferred embodiments of the invention will be described in more detail below with reference to the accompanying figures, in which:

[0042] Figure 1 shows a first embodiment of a fish cage construction according to the invention, where a lice skirt extends down to a bottom ring.

[0043] Figure 2 shows an alternative embodiment of the fish cage construction according to the invention, where the lice skirt ends somewhat higher than shown in fig. 1. Figure 3 shows an alternative embodiment of the fish cage construction according to the invention, where a bottom section extends upwards in the main part of the cage.

[0044] Figure 4 shows an alternative embodiment of the fish cage construction according to the invention, corresponding to fig. 2, but with water supply in the main part of the cage.

[0045] Figure 5 shows an alternative embodiment of the fish cage construction according to the invention, where the lice skirt extends down past the bottom ring.

[0046] Figure 6 shows an alternative embodiment of the fish cage construction according to the invention, corresponding to that in fig. 1 , and with a water outlet in the main part of the cage.

[0047] Figure 7 shows an alternative embodiment of the fish cage construction according to the invention, where a more closed canvas bag is used in the bottom section which achieves an arbitrary shape when filled with heavier water.

[0048] Figure 8 shows an alternative embodiment of the fish cage construction according to the invention, where heavier water is taken from the depths and supplied from above into the lower part of the cage.

[0049] Figure 9 shows an alternative to figure 7 where several smaller volumes of water are used for heavier water.

[0050] Description of preferred embodiments of the invention

[0051] The present invention relates to a floating fish cage construction 10, where the cage construction 10 in a known manner comprises a floating collar 14 which floats in a body of water 16 and a cage 12 equipped with a net 28 for breeding marine organisms, such as fish. The cage construction 10 can also be equipped in a known manner with an impermeable, tapering lower part 12a, preferably in the form of a canvas, but the lower part 12a can also be a solid wall, and an at least partially open main part surrounded by a lice skirt 18. Water flows into the main part of the cage 12 so that it forms a main volume of water.

[0052] The cage 12 is basically intended to be used with a traditional fish cage that has a straight part that runs down into the water from the floating collar with a somewhat "circular cylindrical" shape that transitions into a conical lower part, but the invention is also suitable for use in other types of cages, for instance cages that are conical all the way from top to bottom. The lice skirt 18 can be a fluid permeable skirt or an impermeable skirt depending on which variant of the invention is used.

[0053] The lice skirt 18 preferably encloses the cage 12 around the entire perimeter of the cage, but in locations where there is a constant current direction, although depending on the tide, it is not necessary for the lice skirt 18 to enclose the cage in its entire circumference. It is also possible that some parts of the lice skirt are impermeable, while other parts are fluid permeable.

[0054] The cage construction 10 is anchored in a known manner and can also have a frame mooring 40 which is connected to a mooring ring 32 arranged around the cage 12. Mooring ring can be understood as a ring, but the term mooring ring must also be understood to apply to a reinforcement belt of different designs, or one or several loops / hooks placed on the circumference of the lice skirt 18 and / or on the suspension ropes 26.

[0055] The essential aspect of the present invention is that the lower, impermeable part 12a of the cage 12, which is equipped with a canvas, comprises one or more water inlets 20 for supplying water to a volume of water in said lower part 12a. The water is taken from surrounding or deeper water depths outside a lower part of the main part of the cage 12 and / or the lower part 12a, so that the water that is added to the water volume in the lower part 12a is heavier, i.e. has a higher mass density, than the water that flows into the water volume in the main part of the cage 12.

[0056] This inlet 20 does not have to be an opening in the canvas / wall of the lower part 12a in the bottom section. It could also be a hose or pipe that enters the main part of the cage 12 and goes down towards the bottom of the lower part 12a, as indicated by the arrow 20 in figure 8.

[0057] Furthermore, the lower part 12a of the cage 12 preferably includes one or more water outlets 22. This outlet 22 does not have to be an opening in the canvas / wall of the lower part 12a in the bottom section. It is also conceivable that the water can "flow" over the edge of the lower part 12a and the bottom ring 30, as indicated by the arrow 22 in figure 8. An outlet 34 can also be arranged in a known manner at the bottom of the lower tapered part 12a for disposal of waste, such as feed residues and feces, as well as water. The cage 12 is also equipped in a known manner with a bottom ring 30, in which the lower part 12a filled with heavier water is suspended. It can be a bottom ring as we know it today, but one can also imagine that this is just a series of hooks or rope loops fixed on the circumference of the lower part 12a of the bottom section. The suspension ropes 26 or the wires are attached to these loops or hooks.

[0058] In an embodiment of the present invention, a lower part of the lice skirt 18 can be attached to the bottom ring 30 and an upper part of the lice skirt 18 can be attached to the floating collar 14. This assumes that the lice skirt is strong enough to hold the weight of the lower part 12a with the heavier water.

[0059] The bottom ring 30 can additionally or alternatively be suspended by means of a suspension rope 26 that runs from the floating collar 14 down into the water mass 16. Several suspension ropes 26 are arranged at a distance from each other around the circumference of the floating collar 14.

[0060] The lower part 12a can thus be suspended only by means of the lice skirt 18 or only by means of the suspension ropes 26, or a combination of both suspension forms.

[0061] The suspension ropes 26 can run directly between the floating collar 14 and the bottom ring 30, or the suspension ropes 26 run from the floating collar 14 to the mooring ring 32 and then on to the bottom ring 30. In this case, the mooring ring 32 is arranged in an area between the bottom ring 30 and the floating collar 14.

[0062] As shown in figure 1, the lice skirt 18 lies within the suspension ropes 26. The suspension can go all the way down to the bottom ring 30 at the lower part 12a (the heavier water volume), but the suspension in the form of the suspension ropes 26 can be split either in a loop on the rope or in a ring 38 On this ring 38 or the loop on the suspension rope 26, the suspension rope 26 can be connected to the frame mooring 40 to help keep things in place in the desired position and shape.

[0063] Alternatively, one can also choose to connect the loops or ring 38 to the lice skirt 18 via clip / rope or the like to keep the skirt in place. If necessary, the lice skirt can be given a reinforcement zone / belly belt / ring where this connection takes place. The loop or ring 38 can be connected to the mooring ring 32 via a rope or the like. The lice skirt 18 can be arranged inside or outside the suspension ropes 26. When the lice skirt 18 is placed on the outside of the suspension ropes 26, the suspension will automatically act as a support for the lice skirt.

[0064] Furthermore, the lice skirt 18 can extend down into the water mass 16 to an area between the floating collar 14 and the bottom ring 30 as shown in figures 2-4, for example to the mooring ring 32, which is arranged in an area between the bottom ring 30 and the floating collar 14, and also further from the mooring ring 32 and to the bottom ring 30 as shown in figure 1.

[0065] As shown in figures 3 and 4, parts of the cage's main part 12 can comprise an impermeable canvas 12b which runs from the tapered lower, heavier part 12a and upwards into the body of water 16. For example, up to the mooring ring 32 if this is used.

[0066] If an impermeable canvas 12b is used in the main part of the cage 12, the water volume within can be filled with similar heavier water as in the water volume in the cage's 12 tapered lower part 12a.

[0067] If it is anchored to the existing frame anchoring 40, the anchoring ring 32 can be used. In those cases where it is not anchored to the frame mooring 40, it is not really an anchoring ring but rather a connection between the lice skirt 18, the suspension ropes 26 and the impermeable canvas 12b. When one also connects to the frame mooring 40, one does not need a ring, but instead of a ring, one can use loops or a reinforced belly belt with loops, etc.

[0068] If an impermeable lice skirt is used either from the start or a permeable skirt gets too much marine growth, there will likely be a need for large amounts of external fresh water into the cage 12. In such a case, the cage 12 can be equipped with a dedicated outlet 22' for such water in addition to the water outlet 22 in the lower part 12a. The water outlet 22' can be located in the impermeable canvas 12b in the cage's main part 12, as shown in figures 3 and 4. It may also be possible to oversize the outlet 22 for the heavier water to also be large enough to take away the external water that fills the cage 12 in from the top.

[0069] As shown in figure 4, a water inlet 24 can also be used to supply water to the water volume in the aforementioned main part of the cage 12 in the case of using an impermeable lice skirt or if the permeable lice skirt has become clogged, since water is taken from different water depths outside the cage 12, such as surrounding water. Alternatively, one or more pumps can be used internally in the cage where they suck water from inside the cage 12.

[0070] The water inlet 24 for supplying water to the main part of the cage 12 can, as shown in figure 4, run through the lice skirt 18.

[0071] As shown in figure 6, a water outlet 22' can also run through the lice skirt 18 in an area above the bottom ring 30. Both this water outlet 22' and said water inlet 24 in the main part of the cage 12 are advantageous if the lice skirt becomes clogged.

[0072] Another embodiment of the present invention is shown in figure 5, where the lice skirt 18 extends down to below the upper edge of the cage's heavier water section, i.e. , the lice skirt 18 extends down into the water mass 16 to an area below the bottom ring 30. In this case, the lice skirt 18 is not directly connected the cage 12 and the lower part 12a, but the lower part 12a with heavier water will hold the skirt in place since the heavier water section is stretched due to its excess pressure in relation to surrounding water masses. The lower part of the lice skirt 18 can optionally be equipped with weights 36 in the form of a ring or the like (corresponding also in the variants shown in figures 7 and 8). The suspension ropes 26 to the lower part 12a will be tight because the weight of the heavier water. This will keep the skirt in place and prevent it from being pressed against the net 28. One can also choose to have the diameter of the weight ring 36 smaller than the diameter of the bottom ring 30. This will further limit the deformation of the lice skirt 18.

[0073] The lice skirt 18 can also only, for example, go down 5-15 m. The skirt can thus be placed outside to any height, with and without a bottom ring or weights. The suspension ropes 26 will hold the lice skirt 18 in place. A more design-wise simpler way of supplying the lower part 12a with heavier water can be by means of a hose or pipe which enters from the top, possibly connected to a pump. Penetration of the lower part 12a of the cage 12 is then avoided.

[0074] The lower part 12a of the cage does not have to be tapered. The lower part 12a can also have a cylindrical part if this zone is allowed to become higher and cover slightly upwards. Then the water inlet 20 can be on the cylindrical part of the lower part 12a. At the same time, as said earlier, the inlet 20 can enter from above over the upper edge of the lower part 12a. The whole point is just that the inlet 20 is high enough up on the lower part 12a to fill the desired volume with heavier water. In fact, it is more robust in terms of design to only hang a hose into the lower part 12a from above and let heavier water enter this. Then one avoids penetrating the canvas bag.

[0075] If the speed of the water entering is high enough, the heavier water from the inlet 20 will then still be able to flow down into the lower part 12a and the same effect is achieved. The same effect can also be achieved even if the inlet 20 is geometrically slightly above the outlet 22. This can be achieved by precisely designing the angle and speed of the water in so that it can enter the lower part 12a relatively undisturbed. Undisturbed in the sense that the heavier water can enter 12a without too much change in mass density.

[0076] Figure 7 shows an alternative embodiment of the present invention, and shows a lower part 12a with a volume of water in the form of a closed canvas bag which is filled with heavier water. The water volume created in the lower part 12a of the cage 12 can actually have all kinds of shapes, conical, semi-sphere, closed sphere, cube, etc. If it is open at the top, it can receive waste. If it is closed or partially closed, it is not suitable for receiving waste, but it will still provide the weight needed to keep the lice skirt 18 in the desired position and shape. The canvas bag can similarly be equipped with inlet 20 and outlet 22 (not shown) for water as in the other versions described.

[0077] Figure 9 shows an embodiment in which several closed canvas bags are used which provide several separate water volumes and which together form the lower heavier water part 12a. Each volume has a corresponding option for supplying and discharging heavier water through respective inlet 20 and outlet 22 (not shown) as previously explained.

[0078] In the case of a closed canvas bag, in order to prevent the water from rotting, inlet 20 and outlet 22 can be installed so that the water in the canvas bag 12a remains relatively fresh to avoid damage to the material from which the canvas bag 12a is built or to fish welfare if the canvas bag 12a is open in top or partially open.

[0079] The canvas bag 12a or the suspension ropes 26 can be connected to an external mooring such as, for example, the frame mooring 40 around the cage. The lice skirt 18 can hang freely or be connected to the suspension ropes 26, the additional mooring ring 32, the bottom ring 30 or directly to the canvas bag 12a. Furthermore, corresponding canvas bags filled with heavier water attached to the mooring ring 32 can be used as additional weight.

Claims

Patent claims1. A floating fish cage construction (10), where the cage construction (10) comprises a floating collar (14) that floats in a body of water (16) and a cage (12) with a lower part (12a) equipped with an impermeable wall and at least one partially open main part surrounded by a lice skirt (18), the main part of the cage (12) being arranged for receiving water to form a main volume of water, characterized in that the lower part (12a) of the cage (12) comprises a water inlet (20) for supplying water to a volume of water in said lower part (12a), where water is obtained from surrounding or deeper water depths outside a lower part of the main part of the cage (12) or the impermeable lower part (12a), wherein the water supplied to the water volume in the lower part (12a) of the cage (12) has a higher mass density than the water that flows through said at least partially open main part and into the water volume in the main part of the cage (12).

2. The cage construction (10) in accordance with claim 1 , characterized in that the lower part (12a) of the cage (12) comprises one or more water outlets (22).

3. The cage construction (10) in accordance with claim 1 , characterized in that the cage's lower part (12a) is suspended in a bottom ring (30), the bottom ring (30) being attached to a lower part of the lice skirt (18) and that an upper part of the lice skirt (18) is attached to the floating collar (14).

4. The cage construction (10) in accordance with claim 1 , characterized in that the cage's lower part (12a) is suspended in a bottom ring (30), the bottom ring (30) being suspended by means of a suspension rope (26) that runs from the floating collar (14) .

5. The cage construction (10) in accordance with claim 4, characterized in that the cage (12) comprises a mooring ring (32) arranged in an area between the bottom ring (30) and the floating collar (14), in which the suspension rope (26) runs from the floating collar (14) to the mooring ring (32) and then on to the bottom ring (30).

6. The cage construction (10) in accordance with claim 1 , characterized in that the main part of the cage (12) includes at least one water inlet (24) for supplying water to the water volume in said main part of the cage (12), as water is taken from different water depths outside the cage (12).7 . The cage construction (10) in accordance with claim 6, characterized in that said water inlet (24) for supplying water to the main part of the cage (12) runs through the lice skirt (18).

8. The cage construction (10) in accordance with claim 1 , characterized in that the lice skirt (18) is a fluid permeable skirt or an impermeable skirt.

9. The cage construction (10) in accordance with claim 1 , characterized in that parts of the cage's main part (12) comprise an impermeable canvas (12b), which impermeable canvas (12b) runs from the lower part (12a) upwards into the body of water (16).

10. The cage construction (10) in accordance with claim 9, characterized in that the volume of water in the impermeable canvas (12b) in the main part (12) of the cage is arranged to be filled with similar water with higher mass density as supplied in the water volume in the lower part (12a) of the cage.11 . The cage construction (10) in accordance with claim 1 , characterized in that the lice skirt (18) extends down into the body of water (16) to an area between the floating collar (14) and the bottom ring (30).

12. The cage construction (10) in accordance with claim 1 , characterized in that the lice skirt (18) extends down into the body of water (16) to a mooring ring (32) arranged in an area between a bottom ring (30) and the floating collar (14).

13. The cage construction (10) in accordance with claim 1 , characterized in that the lice skirt (18) extends down into the body of water (16) to an area below a bottom ring (30).

14. The cage construction (10) in accordance with claim 9, characterized in that said impermeable canvas in the cage's main part (12) comprises a water outlet (22').

15. The cage construction (10) in accordance with claim 1 , characterized in that the lice skirt comprises a water outlet (22').

16. The cage construction (10) in accordance with claim 1 , characterized in that the lower part (12a) of the cage (12) has a tapered and conical chamfer.

17. The cage construction (10) in accordance with claim 1 , characterized in that the lower part (12a) of the cage (12) has a circular-cylindrical shape.

18. The cage construction (10) in accordance with claim 1 , characterized in that the cage (12) comprises one or more partially open or closed canvas bags designed to accommodate a water volume of water having higher mass density than surrounding water, said canvas bag (s) forming the lower part (12a).

19. The cage construction (10) in accordance with claim 1 , characterized in that the wall of lower part (12a) is made of impermeable canvas.

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