EA040682B1 - FISH FARMING AND METHOD OF ITS MANAGEMENT - Google Patents

Description

This invention relates to a fish farm and a method for managing a fish farm, in particular a fish farm suitable for fish farming on land.

State of the art

The fish farming industry has been growing continuously over the past few years and forms a significant part of the economy in many countries such as Norway. With the increase in production, issues such as pollution, fish care and the impact of industry on the environment remain in the spotlight among both regulators and environmentalists. In addition, there is a continuing need for more efficient production systems and methods to minimize energy consumption and otherwise optimize production.

Documents useful in understanding the prior art include CN 203399619 U, US 2017325427 A, EP 1185168 B1, CN 204670146 U, and US 3888210 A.

This invention aims to develop systems and methods for fish farms that provide advantages over conventional methods or at least alternatives.

The essence of the invention

In one embodiment, a fish farm is provided having at least one above ground fish tank and a water supply system, the water supply system comprising a supply line and a return line, the supply and return lines being fluidly connected to a water reservoir;

intermediate fluid capacity;

a circulation pipeline connected in fluid medium with the specified at least one fish tank; and a valve mechanism fluidly connected to the supply line, the return line, the intermediate fluid reservoir, and the circulation conduit, the valve mechanism having a first operating configuration in which the valve mechanism permits circulation of fluid between the intermediate fluid reservoir and said at least one cage through the circulation pipeline, while preventing the flow of fluid between the intermediate tank and the supply and withdrawal lines; and a second operating configuration in which the valve mechanism permits circulation of fluid between the intermediate reservoir and the reservoir through the supply and withdrawal lines while preventing fluid from flowing between the intermediate reservoir and the circulation conduit.

In one embodiment, a method is provided for operating a fish farm having at least one above ground fish tank, the method including the steps of (i) bringing an intermediate fluid container into fluid communication with a water reservoir and circulating water from the reservoir water through the intermediate fluid container into the water reservoir, while preventing fluid from flowing between the intermediate fluid container and the fish tank; and (ii) bringing the intermediate fluid container into fluid communication with said at least one ground fish tank and circulating water between the intermediate fluid container and the fish tank while preventing fluid from flowing between the intermediate container and the tank, while steps (i) and (ii) are carried out as separate, sequential steps.

In one embodiment, a fish farm is provided with at least one terrestrial fish tank located at some location elevated compared to the tank, the fish farm having a water supply system comprising a supply line and a return line, wherein the supply and return lines are connected at a fluid medium with a water reservoir and a fish tank;

a pump located in the supply line;

a turbine located in the outlet line; and a connection connecting the pump to the turbine, whereby the turbine is configured to generate power from the water flow in the outlet line and supply power to the pump through said connection.

Brief description of the drawings

Various features will become apparent from the following description of exemplary embodiments, given by way of non-limiting examples with reference to the accompanying drawings, wherein FIG. 1 is a schematic plan view of a fish farm according to an embodiment in a first operational state;

in fig. 2 is a schematic perspective view of the fish farm shown in FIG. 1;

- 1 040682 in Fig. 3 is a schematic plan view of a fish farm in a second operating state;

in fig. 4 is a schematic perspective view of the fish farm shown in FIG. 3;

in fig. 5 is a schematic view of a fish farm according to yet another embodiment;

in fig. 6 is a schematic view of a fish farm according to yet another embodiment;

in fig. 7 is a schematic view of a fish farm according to yet another embodiment.

Detailed description

Land-based fish farms are known and widely used for fish incubation and rearing of juvenile fish (eg, silver juvenile salmon) before transferring the fish to fish feathers. For many species of fish and in many regions, there is the possibility of farming on land throughout their life cycle, and in recent years, increased attention has also been paid to the use of farms on land for fish that are traditionally farmed in marine farms. An example of this is the use of onshore farms to raise salmon past the stage of silver salmon, and even to raise salmon (full production cycle).

Such onshore farms usually contain a number of fish cages and a water supply system to ensure that the water for the cages is rotated. The water supply system may be connected to a reservoir or source, which is a fresh water source, a sea water source, or both. In order to care for the fish and to optimize production, it is necessary to have a minimum water consumption for changing the water in the cages. This requires energy, and it is desirable to minimize the use of such energy in order to minimize energy costs while ensuring that environmental conditions in the fish tanks remain acceptable.

In one embodiment in accordance with the present invention, illustrated in FIG. 1 and 2, a fish farm is provided having at least one above ground fish tank 1a-1e and a water supply system 100. The water supply system 100 comprises supply lines 2C, 2D and output lines 2A, 2B, the supply and output lines 2A-2D being fluidly connected to the water reservoir 3 and adapted to provide water to replace part of the water in the fish tanks 1a-1e. Part of the water in the fish cages 1a-1e is usually removed through the bottom of the fish cage 1a-1e, however, the drained water can also, for example, be collected through the side outlet of the fish cage 1a-1e. Feed lines 2C, 2D in this embodiment are shown as two separate, but may be one line, or they may be fluidly connected to the downstream section of feed lines 2C, 2D shown in FIG. 1 and 2. Similarly, the outlet lines 2A, 2B may be formed as a single line or may be fluidly connected.

Each fish cage 1a-1e is filled with water 4 as shown in connection with the cage 1e in FIG. 2 to level 4a, which forms the top water surface of the cage. The water 4 may be sea water, fresh water, or a mixture thereof, in accordance with the type of fish being farmed and industry recommendations. In general, the top water surface 4a is the same in all cages 1a-1e, however this is not necessary and different water levels can be used in different cages, for example to correct the amount of biomass in the cage or for special purposes such as drug treatment.

The water reservoir 3 may be lower than the upper water surface 4a in the fish cages 1a-1e, or lower than all of the fish cages 1a-1e together. The water reservoir 3 may be a common supply and withdrawal reservoir 3, for example by sea, as in the case of the embodiment shown in FIG. 1 and 2. Both the supply and return lines 2A-2D are then laid in the sea, collecting seawater in the supply lines 2C, 2D and discharge from the return lines 2A, 2B. Alternatively, the water tank 3 may comprise separate supply and withdrawal tanks, such as water tanks. They can be, for example, water tanks located near the fish tanks 1a-1e, or they can be distal to the fish tanks 1a-1e, but connected by pipelines. It may be desirable, for example, to provide a withdrawal tank for the purpose of cleaning the discharge water from the fish cages 1a-1e, for example in order to remove suspended particles and/or wastes present in the discharge water.

The water supply system 100 also includes an intermediate fluid container 5, 6 . The intermediate vessel 5, 6 is configured to store some volume of water, and may be any type of container or structure suitable or suitable for this purpose, such as a pipe, a fluid tank, or a combination of both. In FIG. 1 and 2, the intermediate vessel 5, 6 is shown simply as tubes 5, 6. In this embodiment, the intermediate vessel 5, 6 comprises a first fluid tube 5 and a second fluid tube 6 arranged in a parallel arrangement, which will be described in more detail below. The intermediate container 5, 6 can also be a cage similar to the fish cages 1a-1e, forming a buffer storage for water.

The intermediate tank 5, 6 can be located higher than the fish cages 1a-1e, on such

- 2 040682 the same height as the fish cages 1a-1e, or lower than the fish cages 1a-1e. The intermediate vessel 5, 6 is advantageously located at the same height as the fish cages 1a-1e, or at some height which is between the heights of the fish cages 1a-1e and the tank 3. However, the intermediate vessel 5, 6 may be at some other height; for example, if the tank 3 is the sea, the intermediate tank 5, 6 may be partly or wholly located in the sea or slightly above sea level.

The water supply system 100 further comprises a circulation conduit 9a-9d fluidly connected to the fish tanks 1a-1e, valves 10a-10d fluidly connected to the supply and withdrawal lines 2A-2D with an intermediate tank 5, 6, and a circulation conduit 9a -9d for the intermediate vessel 5, 6. In the embodiment shown, the valves 10a-10d are shown as four three-way valves, the three-way valves 10a, 10b being fluidly connected to the outlet lines 2A, 2B, the intermediate vessel 5, 6 and the circulation line 9a- 9d, and the three-way valves 10c, 10d are fluidly connected to the supply lines 2C, 2D by the intermediate vessel 5, 6 and the circulation conduit 9a-9d. However, the function of the valves shown here, described in more detail below, can be implemented in many ways and the invention is not limited to any particular valve mechanism. For example, it may be possible to use a set of individual standard valves to implement the same functionality, or to use one or more large valve blocks with multiple piping and sealing elements located within the same block. Alternatively, the system and method can be implemented without valves by changing and connecting or disconnecting the relevant pipelines and fluid lines manually.

The valves 10a-10d have a first operating configuration in which the valves 10a-10d allow fluid to flow between the intermediate fluid tank 5, 6 and the circulation conduit 9a-9d and prevent fluid from flowing between the intermediate tank and supply and return lines 2A-2D, and a second operating configuration in which valves 10a-10d allow fluid to flow between the intermediate vessel 5, 6 and supply and return lines 2A-2D and prevent fluid from flowing between the intermediate vessel 5, 6 and circulation conduit 9a-9d.

The water supply system 100 also includes pumps 7, 8 driven to allow water to flow between the intermediate vessel 5, 6 and the circulation conduit 9a-9d, as well as between the supply line 2C, 2D through the intermediate vessel 5, 6 to the line 2A, 2V outlet. In the embodiment shown in FIG. 1 and 2, the pumps 7, 8 are located in the intermediate vessel 5, 6, whereby the pumps 7, 8 can perform both of the above functions. Alternatively, the pumps 7, 8 may be located elsewhere in the water supply system 100. For example, the first pump may be located in the supply lines 2C, 2D, outlet lines 2A, 2B, or intermediate fluid tank 5, 6, and the second pump may be located in the circulation line 9a-9d. Any pump configuration can be used that can circulate water between the intermediate tank 5, 6 and the fish tanks 1a-1e through the circulation conduit 9a-9d, and between the tank 3 and the intermediate tank 5, 6 through the supply and withdrawal lines 2A-2D.

In operation, the water supply system 100 allows water to circulate to and from the one or more fish cages 1a-1e from the tank 3. (Each la-1e cage may have additional valves or throttling elements to control the flow of water into or out of the respective cage.) the fluid connection between the intermediate vessel 5, 6 and the circulation pipe 9a-9d (and hence the fish tanks 1a-1e) is closed. By means of the pump(s) 7, 8, the intermediate vessel 5, 6 will be filled with fresh water from the reservoir 3 through the supply lines 2C, 2D, while the effluent present in the intermediate vessel 5, 6 (described below) will be removed through the lines 2A, 2V outlet.

In the second part of the sequence, the fluid connection between the supply and return lines 2A-2D and the intermediate tank 5, 6 is closed, and the connection between the intermediate tank 5, 6 and the circulation conduit 9a-9d (hence the fish tanks 1a-1e) is open . The pump(s) 7, 8 are actuated to circulate the water in the intermediate tank 5, 6 to the fish cages 1a-1e through the circulation conduit 9a-9d, and the water withdrawn from the fish cages la-1e this will circulate into the intermediate tank 5, 6. Thus, fresh water is supplied to the fish cages 1a-1e, and the diverted water, now present in the intermediate tank 5, 6, can be diverted by repeating the first part of the sequence (see previous paragraph).

In the embodiment shown in FIG. 1 and 2, the intermediate vessel 5, 6 comprises a first fluid conduit 5 and a second fluid conduit 6 arranged substantially in parallel. The valve mechanism 10a-10d is actuated to actuate two parallel lines at the same time so that one side circulates to the fish tanks 1a-1e,

- 3 040682 and the other circulates with the tank 3. Therefore, one side can achieve continuous operation and circulation to cages 1a-1e if desired or required, although each line operates in series as described above.

These different parts of the sequence are shown in more detail in FIG. 1-4. In FIG. 1 and 2, valves 10a and 10c are shown open so that pipe 5 can circulate to fish tanks 1a-1e, and valves 10b and 10d are shown open so pipe 6 can circulate to tank 3. In FIG. 3 and 4 show the changeover after which pipe 5 circulates to tank 3 and pipe 6 to cages 1a-1e. In this way, an almost continuous circulation of fresh water to the fish tanks 1a-1e can be achieved. However, it is possible to use only one intermediate container 5, 6 of such a volume that the circulation to the fish tanks 1a-1e will be intermittent. This depends on the requirements in any given case, for example on the required fresh water supply rate to cages 1a-1e.

Alternatively, the pumps 7, 8 can be omitted and the system can be circulated by natural flow using differences in temperature and density of the water. Optionally, for example, pumps can be provided for only one of the circulation lines, due to which the circulation from the tank 3 to the intermediate tank 5, 6 is carried out due to the natural flow, and the circulation between the intermediate tank 5, 6 and cages 1a-1d is carried out by means of pumps .

Circulation with the help of natural flow can be achieved, for example, if there are differences in water temperatures in different parts of the flow lines. Since the gravity of water is generally greatest (i.e., water has the highest density) at a temperature of approximately 4 degrees Celsius (°C), it is possible, for example, to collect water that is colder than the water of the sea reservoir 3. Since water can warm up slightly during the process (e.g. by the heat of the farmed fish or heat exchange with the components of the fish farm), the water flowing out through the return lines 2A, 2B will be denser than the water flowing into the supply lines 2C, 2D, resulting in a natural flow based on gravity. The same effect can be achieved, for example, by placing a heat exchanger in the outlet lines 2A, 2B, to cool the outlet water (or in the supply lines 2C, 2D.) In particular, this effect may be appropriate, for example, in cold climates and / or during the winter season, when the availability of a reservoir of cold water and/or cold air from outside for cooling purposes may be in excess.

Therefore, in accordance with the embodiments of the present invention, it is possible to achieve improved fish farming and water supply systems for fish farms, in particular farms on land. By providing a closed circuit between the tank 3 and the intermediate tank 5, 6, when exchanging water with the tank 3, the effect of any height difference between the tank 3 and the fish tanks 1a-1e can be significantly reduced. Thus, the pumps 7, 8 generally only need to overcome the friction and flow resistance in the pipes, and there is no need to provide energy to raise the water to a higher level, or in certain embodiments, the pumps 7, 8 are not needed at all. Immediately after filling the intermediate container 5, 6, the exchange of water with the fish cages 1a-1e is also essentially only possible with the pumping energy necessary to overcome the resistance to flow in the pipes. This avoids, for example, placing the fish cages 1a-1e partly below sea level in land-based fish farms that exchange water with the sea, as is usually done to avoid excessive use of energy. This requires a much larger volume of construction work, and hence higher capital investment in the construction of a fish farm, and significantly limits the allowable sites on which such fish farms can be built. In accordance with the embodiments presented here, the freedom to locate such fish farms on land at the most convenient location is greatly increased while avoiding the cost of increased energy use for water circulation.

In some embodiments, it may be desirable to have sensors, sampling units and/or cleaning systems in a fish farm. This can advantageously be realized by connecting them to an intermediate vessel 5, 6 and/or a circulation line 9a-9d. This provides direct access to the water supplied to the cages 1a-e and/or the water withdrawn from them. For example, if the water from the cages 1a-1e is not of the proper quality for discharge to the sea, it may be provided to circulate it through a treatment system connected, for example, to a circulation pipe 9a-9d, before it is discharged through the outlet lines 2A, 2B, or the water may be diverted to a separate cage or a separate system for cleaning or diverting. This can be done without the bleed fluid coming into contact with the bleed lines 2A, 2B, and therefore a reduced risk of unintentional bleed of, for example, contaminated water can be achieved. The circulation of water through the purification system can also be carried out at the same height as the intermediate tank 5, 6 and the circulation pipe 9a-9d, thereby reducing energy use.

In FIG. 5 shows another embodiment of a fish farm with at least one above ground fish tank 1a-1e, which is located in an elevated position compared to a reservoir 3, such as a seawater reservoir. The fish farm has a 100 feed system

- 4 040682 water containing line 2C supply and line 2A outlet, and lines 2A, 2C supply and outlet connected in fluid medium with the tank 3 water and fish cages 1a-1e to replenish water in fish cages 1a-1e in the same way as described above. A pump 21 is disposed in the supply line 2C, the pump 21 being driven to pump water from the reservoir 3 into the fish tanks 1a-1e. The pump 21 may be any type of pump, such as a rotodynamic pump, a positive displacement pump, or any other suitable type of pump. Disposed in line 2A is a water motor, in this embodiment a turbine 22. Alternatively, the water motor may be a reciprocating machine or any other suitable type of machine. The turbine 22 is configured to generate power from the water flow in the outlet line 2A. This power may be mechanical power, electrical power or hydraulic power. Pump 21 and turbine 22 are connected by connection 23, whereby turbine 22 can supply power to pump 21 through connection 23.

In FIG. 5, connection 23 is shown as a mechanical connection, in this case a shaft, but the mechanical connection may be other, such as a gear, chain, belt, or any other connection suitable for power transmission. Alternatively, the connection may be an electrical connection, whereby the turbine 22 will generate electrical power, for example, by means of an electrical generator connected to the impeller of the rotodynamic turbine, and the electrical connection 23 will transfer this energy to the pump 21. In this case, the drive of the pump 21 itself is possible from an electric motor. Another alternative for the connection is hydraulic, for example, in which the turbine 22 generates hydraulic power, which is fed through the hydraulic connection 23 to the pump 21.

In this embodiment, a reduction in the energy use of the fish farm can be achieved, since it is possible to recover some of the energy used to transfer water from the tank 3 to the cages 1a-1e in the turbine 22.

In FIG. 6 shows yet another embodiment providing for three intermediate tanks 5, 6, 56. Each tank 5, 6, 56 has proper valves 10e-10p so that each tank can be fluidly connected to supply and return lines 2D, 2B. or with a circulation conduit 9e, 9f which interconnects the tanks 5, 6, 56 with the fish tanks la, 1b in the same way as described above.

In this embodiment, two pumps 24, 26 are located in the circulation line 9e, 9f, and two pumps 25, 27 are located in the supply and return lines 2D, 2B. Optionally, one pump in the circulation line 9e, 9f and one in the lines 2D, 2B inlet and outlet, or alternatively a pump may not be needed if natural flow can be obtained, for example, based on density differences.

In the embodiment shown in FIG. 6, the valves 10e-10p can be configured such that each of the tanks 5, 6, 56 is switched in series between circulation to the fish tanks la, 1b and to tank 3, but with such a phase shift that at least one of the tanks 5, 6, 56 will circulate to the fish cages 1a, 1b at any time, and at least one of the tanks 5, 6, 56 will circulate to the tank 3. This can be achieved, for example, by switching the cages 5, 6, 56 so as to drive them 120° out of phase between them. This provides the advantage that in the supply and return lines 2D, 2B and in the circulation conduit 9e, 9f a continuous flow of fluid can be obtained, since one fluid circuit will always be open and flowing. This can reduce the power consumption of the pumps 24-27, prevent pressure variations (eg, pressure surges due to valve actuation) in the system, and provide a smoother flow of fluid to the fish tanks la, 1b.

Although in the embodiment shown in FIG. 6, three containers 5, 6, 56 are shown, other embodiments may include more containers such as four, five, six or even more. These containers can be switched in some scrolling sequence or, for example, in pairs; for example, in one embodiment with six containers, the switching of pairs of containers may be joint.

In FIG. 7 shows another embodiment in which the first and second fluid containers 5, 6 are located in a common container 71, this container 71 being rotatable and having a configuration that in the first angular position provides fluid connection of the first fluid container 5 with supply and return lines 2B, 2D and fluid connection of the second fluid container 6 with the circulation pipeline 9b, 9c, and in the second angular position provides fluid connection of the second fluid container 6 with supply and return lines 2B, 2D and connection along the fluid of the first fluid container 5 with circulation conduit 9a-9f.

The container 71 in this embodiment is cylindrical, and the rotation of the container 71 can take place, for example, around the horizontal central axis 72 of the body of the cylindrical container. To this end, the container 71 can be supported by support elements 73a, 73b. Switching between

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Claims (18)

the fluid connection with the tank 3 or with the fish cages 1a, 1b can be organized, for example, by means of spool valves located in the tank 71 or associated with it, so that the tank 5, 6 of the fluid, which at any time faces in the direction of the circulation of the conduit 9b, 9c is brought into fluid contact with it, and the fluid container 5, 6, which at any time faces the supply and return lines 2B, 2D, is brought into fluid contact with them. Valves 10q-10t may be provided to close the relevant fluid lines, however these valves are not essential for the operation of the system. Similar to what is described above, pumps 24-27 can be provided. The embodiment shown in FIG. 7 may optionally provide additional containers operating in the same way. The invention is not limited to the embodiments described above; in this regard, reference should be made to the appended claims. CLAIM 1. A fish farm having at least one ground fish tank (1a1e) and a water supply system (100), the water supply system (100) comprising a supply line (2C, 2D) and a discharge line (2A, 2B), wherein lines (2A-2D) of supply and discharge are connected in fluid medium with a reservoir (3) of water; intermediate container (5, 6, 56) of the fluid; a circulation pipeline (9a-9f) connected in fluid medium with said at least one fish tank (1a-1e); a valve mechanism (10a-10p) connected in fluid medium to a supply line (2C, 2D), a discharge line (2A, 2B), an intermediate fluid reservoir (5, 6, 56) and a circulation pipeline (9a-91), moreover the valve mechanism (10a-10p) has a first operating configuration, in which the valve mechanism (10a-10p) circulates fluid between the intermediate fluid reservoir (5, 6, 56) and said at least one cage (1a-1e) through circulation pipeline (9a-9f); a second operating configuration in which the valve mechanism (10a-10p) circulates fluid between the intermediate fluid reservoir (5, 6, 56) and the reservoir (3) through supply and withdrawal lines (2A-2D); and a first valve block (10a, 10b) fluidly connected to an outlet line (2A, 2B), an intermediate vessel (5, 6) and a circulation pipe (9a-9d); and a second valve block (10c, 10d) fluidly connected to the supply line (2C, 2D), intermediate vessel (5, 6) and circulation conduit (9a-9d). 2. Fish farm according to claim 1, containing at least one pump (7, 8, 24, 25, 26, 27) driven to ensure the flow of water between the intermediate tank (5, 6, 56) and the circulation pipeline (9a-9f) and/or from the supply line (2C, 2D) through the intermediate vessel (5, 6, 56) to the withdrawal line (2A, 2B). 3. Fish farm according to any previous paragraph, in which the reservoir (3) of water is lower than the upper surface (4a) of the water, in the specified at least one fish cage (1a-1e); or lower than said at least one fish tank (1a-1e). 4. A fish farm according to any of the preceding claims, in which the water reservoir (3) comprises a common supply and discharge reservoir (3), for example, in which the water reservoir (3) is the sea. 5. A fish farm according to any one of claims 1 to 3, wherein the water tank (3) comprises separate supply and withdrawal tanks. 6. Fish farm according to any previous claim in combination with claim 2, wherein said at least one pump (7, 8, 24, 25, 26, 27) comprises a pump (7, 8, 24, 25, 26, 27 ) located in the intermediate container (5, 6, 56); or a first pump located in the supply line (2C, 2D) or outlet line (2A, 2B) and a second pump located in the circulation pipe (9a-9f). 7. Fish farm according to any previous paragraph, in which the intermediate capacity (5, 6, 56) is located higher than the specified at least one fish tank (1a-1e); at the same height as said at least one fish tank (1a-1e); lower than said at least one fish tank (1a-1e); between the specified at least one fish cage (1a-1e) and the tank (3) water; or - 6 040682 partly or completely inside the water tank (3). 8. A fish farm according to any of the preceding paragraphs, in which an intermediate container (5, 6, 56) comprises a fluid container, wherein the fluid container is at least one of a pipe and a fluid container. 9. Fish farm according to any previous paragraph, in which the intermediate container (5, 6, 56) contains the first fluid container (5) and the second fluid container (6), while the valve mechanism (10a-10p) is actuated, in order to simultaneously maintain a fluid connection between the supply and withdrawal lines (2A-2D) and the first fluid container (5); and maintain a fluid connection between the circulation conduit (9a-9f) and the second fluid container (6). 10. Fish farm according to any previous paragraph, in which the intermediate container (5, 6, 56) contains a third container (56) of the fluid, while the valve mechanism (10a-10p) is actuated to independently control each of the first, second and a third container (5, 6, 56) to keep them in fluid communication with supply and discharge lines (2A-2D); or in fluid connection with the circulation pipeline (9A-9D). 11. A fish farm according to any previous claim in combination with claim 9, wherein the first and second fluid containers (5, 6) are rotatable and configured in such a way that, in the first angular position, fluid connection of the first container (5) is achieved. fluid medium with lines (2A-2D) of supply and discharge and fluid connection of the second container (6) of the fluid medium with the circulation pipeline (9a-9D); a in the second angular position provides a fluid connection of the second fluid container (6) with supply and withdrawal lines (2A-2D) and a fluid connection of the first fluid container (5) with the circulation pipeline (9a-9D). 12. A method for operating a fish farm according to any one of claims 1 to 11, comprising the steps of (i) bringing the fluid container (5, 6, 56) into fluid communication with the water reservoir (3) and circulating water from tank (3) water through the container (5, 6, 56) fluid into the tank (3) water; and (ii) bringing the fluid container (5, 6, 56) into fluid communication with said at least one ground fish tank (1a-1e) and circulating water between the fluid container (5, 6, 56) and fish cage (1a-1e), while steps (i) and (ii) are carried out as separate, sequential steps. 13. The method according to claim 12, in which the container (5, 6, 56) is the first container (5, 6, 56) of the fluid, and the method further includes the steps of (iii) bringing the second container (5 , 6, 56) fluid in fluid communication with the water tank (3) and circulate water from the water tank (3) through the second fluid container (5, 6, 56) into the water tank (3); and (iv) bringing the second fluid container (5, 6, 56) into fluid communication with said at least one ground fish tank (1a-1e) and circulating water between the second fluid container (5, 6, 56). medium and fish tank (1a-1e), while steps (iii) and (iv) are carried out as separate, sequential steps (i), while steps (i) and (iv) are carried out simultaneously and steps (ii) and ( iii) carried out simultaneously. 14. The method according to claim 12 or 13, in which the reservoir (3) of water is lower than the upper surface (4a) of the water, in the specified at least one fish tank (1a-1e); or lower than said at least one fish tank (1a-1e). 15. The method according to any one of claims 12 to 14, wherein the water reservoir (3) comprises a common supply and discharge reservoir (3), for example, wherein the water reservoir (3) is the sea. 16. Method according to any one of claims 12 to 14, wherein the water reservoir (3) comprises separate supply and withdrawal reservoirs. 17. The method according to any one of claims 12 to 16, wherein the step of circulating water from the water tank (3) through the fluid container (5, 6, 56) into the water tank (3) is carried out by means of a pump (7, 8, 25 , 27) located in the container (5, 6, 56) of the fluid; a pump located in the supply line (2C, 2D) or the outlet line (2A, 2B) connecting the fluid container (5, 6, 56) to the water reservoir (3); or natural flow, caused by differences in temperature and density in the water. 18. Method according to any one of claims 12-17, wherein the step of circulating water between the fluid container (5, 6, 56) and the fish tank (1a-1e) is carried out by means of a pump (7, 8, 24, 26), located in the container (5, 6, 56) fluid; -