WO2019098848A1

WO2019098848A1 - Method for continual fish farming in a fish farm set in a body of water

Info

Publication number: WO2019098848A1
Application number: PCT/NO2018/050277
Authority: WO
Inventors: Knut Vangen; Vidar VANGEN
Original assignee: Knut Vangen; Vangen Vidar
Priority date: 2017-11-17
Filing date: 2018-11-15
Publication date: 2019-05-23
Also published as: NO20171836A1

Abstract

Method for continual fish farming in a fish farm set in a body of water, where the fish farming is carried out in a fish farm comprising a number N of fish pen sections arranged in a wheel pattern, where a central production unit forms the hub, and the wheel pattern has N spokes radially evenly distributed out from the hub, where each of the N sea pen sections is arranged adjacent to two of the spokes, and each sea pen section comprises 3 sea pens, one inner sea pen arranged tangentially to the hub and two sea pens arranged outside the inner sea pen, where the farming in the fish pens is time-lagged to achieve an even fish production over time form the fish farm, and this is achieved by delaying the start of production in each of the fish pen sections by introducing fish into the fish pens in the following order: (a) introducing fish into one of the 3 fish pens in the first fish pen section (b) waiting for a time period Δt before introducing fish into one of the 3 fish pens in the second fish pen section, (c) wait for an additional time period Δt before introducing fish in one of the 3 fish pens in the next fish pen section, (d) repeat step (c) until one of the 3 fish pens in all the N fish pen sections is filled, where Δt is given as Δt=T/2N and T is the total time for a production cycle in the fish farm where F is the time the fish spend in the fish farm, and P is the time it takes from a fish pen is emptied of fish in order to be cleaned and prepared until the fish pen is again filled with fish, and T=F+2P, and where each individual sea pen section is operated as follows: (e) fish is introduced into one of the first 3 fish pens in the fish pen section as given in (a) and have a retention time therein of ½ F, (f) after ended retention time in the first fish pen in the fish pen section the fish is moved therefrom and divided among the remaining fish pens in the fish pen section, where they have a retention time of ½ F before they are removed from the two remaining fish pens in the fish pen section and from the fish farm, (g) when the first fish pen in the section is emptied, it is cleaned and prepared during time P, and then a new batch of fish is introduced therein, (h) when the two remaining fish pens in the section is emptied, they are cleaned and prepared during time P and then a new batch of fish is introduced therein from the first fish pen in the section, (i) steps (g) and (h) are repeated continuously.

Description

TITLE: Method for continual fish farming in a fish farm set in a body of water

Field of the invention

The present invention relates to a method for continual fish farming in a fish farm set in a body of water, as well as a fish farm adapted to practice the method.

Background, disclosure of the state of art, and objects of the present invention

The way fish farming is usually practiced currently, one usually will fill several fish pens with fish simultaneously, and also harvest them simultaneously. This results in large variations over time both in resource use, like how much used, how much waste generated, and how much work is needed, and not the least how much fish is harvested. If a more even production can be achieved at a fish farm the process can be made substantially more practical and much more cost effective. By harvesting fish from a farm continually one will also be less exposed to swings in the market.

In order to achieve continual production in fish farming using known technique currently one must have many fish pens in many fish farms, and coordinate them. Achieving an even production is still very challenging, and will be spread out over a large area. When the production is moved on land this can be somewhat alleviated, but is still problematic.

Thus, there is a need for a method for continual fish farming in a fish farm set in a body of water, where one have an even production of fish over time. The present invention is a solution to this problem.

Summary of the invention

The method according to the present invention is characterized in that the fish farming is carried out in a fish farm comprising a number N of fish pen sections arranged in a wheel pattern, where a central production unit forms the hub, and the wheel pattern has N spokes radially evenly distributed out from the hub, where each of the N sea pen sections is arranged adjacent to two of the spokes, and each sea pen section comprises 3 sea pens, one inner sea pen arranged tangentially to the hub and two sea pens arranged outside the inner sea pen, where the farming in the fish pens is time-lagged to achieve a even fish production over time form the fish farm, and this is achieved by delaying the start of production in each of the fish pen sections by introducing fish into the fish pens in the following order:

(a) introducing fish into one of the 3 fish pens in the first fish pen section

(b) waiting for a time period At before introducing fish into one of the 3 fish pens in the second fish pen section,

(c) wait for an additional time period At before introducing fish in one of the 3 fish pens in the next fish pen section,

(d) repeat step (c) until one of the 3 fish pens in all the N fish pen sections is filled,

where At is given as At=T/2N and T is the total time for a production cycle in the fish farm

where F is the time the fish spend in the fish farm, and P is the time it takes from a fish pen is emptied of fish in order to be cleaned until the fish pen is again filled with fish, and

T=F+2P, and

where each individual sea pen section is operated as follows:

(e) fish is introduced into one of the first 3 fish pens in the fish pen section as given in (a) and have a retention time therein of ½ F,

(f) after ended retention time in the first fish pen in the fish pen section the fish is moved therefrom and divided among the remaining fish pens in the fish pen section, where they have a retention time of ½ F before they are removed from the two remaining fish pens in the fish pen section and from the fish farm,

(g) when the first fish pen in the section is emptied, it is cleaned and prepared during time P, and then a new batch of fish is introduced therein, (h) when the two remaining fish pens in the section is emptied, they are cleaned and prepared during time P and then a new batch of fish is introduced therein from the first fish pen in the section,

(i) steps (g) and (h) are repeated continuously.

In accordance with a preferred embodiment of the method N=4-8, more preferably N=5-7, and most preferred N=6.

In accordance with a preferred embodiment of the method F=4-24 months, preferably F=8-14 months, more preferred F= 10-12 months, and most preferred F= 1 1 months. More preferred F=11 months, T=12 months, and P=1/2 month.

In accordance with a preferred embodiment of the method the water temperature in the fish pens is kept within a temperature variation of +/- 5°C of the desired temperature, preferably +/- 3°C, and more preferred +/- 2°C. It is preferred that the water temperature in the fish pens is kept stabile enough over long time production for the fish to grow at an approximately even rate.

The fish farm in accordance with the present invention is characterized by

comprising a number N fish pen sections arranged in a wheel pattern, where a central production unit forms the hub, and the wheel pattern has N spokes radially evenly distributed out from the hub, where each of the N sea pen sections is arranged adjacent to two of the spokes, and each sea pen section comprises 3 sea pens, one inner sea pen arranged tangentially to the hub and two sea pens arranged outside the inner sea pen.

In accordance with a preferred embodiment of the fish farm N is 6.

In accordance with a preferred embodiment of the fish farm the central production unit comprises water intake, water treatment, feed silos, sludge handling, operation controls, and ballast for the entire sea farm. Description of the figures

Preferred embodiments of the present invention will now be described in more detail, with reference to the following figures, wherein:

Figure 1 shows a sea farm set in a body of water in accordance with the present invention, seen from above, where N=6. Figure 1 a shows only one sea pen section with the sea pens drawn, while figure 1 b show all the sea pen sections with sea pens drawn.

Figure 2 shows a perspective of the sea farm of figure 1 , seen from the side.

Figure 3 shows a perspective cross-section of the central production unit, where the floors therein are shown.

Figure 4 shows a sketch of a cross-section of the central production unit, of the floor where the feed silos are kept.

Figure 5 shows a fish farm arranged floating in accordance with the present invention, seen from above, where N=5.

Description of preferred embodiments of the invention

In accordance with the present invention, the fish farm comprises a number N of fish pen sections, where each section comprises 3 fish pens. The fish pens are round or approximately round when seen from above, the fish pen sections are arranged in a wheel pattern when seen from above, where the central production unit forms the hub in the wheel pattern. The wheel pattern has N spokes, evenly distributed out from the hub. The spokes separates the N fish pen sections, so that the sea pen sections are arranged adjacent to two of the spokes (with one on each side and the hub in the middle). Each section comprises 3 sea pens, an inner sea pen arranged tangent to the hub and two fish pen arranged outside the inner fish pen. The number of sections N is preferably 4-8, more preferred 5-7, and according to the most preferred embodiment of the present invention the number of sections N is 6. This is shown in figures 1 , 2 and 4. With 6 sections of 3 fish pens each the arrangement as shown in the figures is achieved, This results in the most packed distribution of circular fish pens in sections of 3 fish pens, and the most optimal utilization of space. This makes it possible to have fish pens with an equal size where the number of fish pens adjacent to the central production unit (6 fish pens) is half of the number of fish pens distributed in a ring outside these (12 fish pens), and all the fish pens are packed close, without any additional room in-between them. With 5 or 7 sections the arrangement is still good, but not as perfect as wit 6 sections, and if one use less than 4 sections or more than 8 sections there is a lot of unused space between the fish pens, and this is less useful. In other words, the further away from 6 sections one gets, the more not usable space one will have between the fish pens. In addition, 6 sections is a preferred number since the harvesting frequency then will be advantageous, as will be explained herein.

With reference to figure 1 a fish farm is shown in accordance with the present invention, with six fish pen sections 2. Each of the fish pen sections 2 has three fish pens 1 therein, even if only one of the fish pen sections is shown filled up with fish pens in figure 1 a, since this figure focus on the sections, not the individual fish pens. Figure 1 b shows all the fish pen sections filled with fish pens in the manner the fish farm will look like when in use. In the middle of the fish farm there is arranged a central production unit 5. The spokes 4 in the wheel pattern are shown herein between the fish pen sections 2, and the entire fish farm is surrounded/ limited by an outer edge 3. The spokes 4 and the outer edge 3 will function as access points to the fish pens.

With reference to figure 5, a fish farm is shown that is equivalent to the one shown in figure 1 , but with the substantial difference that here only five fish pen sections are used, not six as in figure 1 . It is very apparent from the figure that one thus achieve a less optimal densely packed of the fish pens 1 therein, with more space surrounding them. But if a lot of space is desired between the sections, or more space for walkways, pipes etc., on the spokes 4, one may of course choose this embodiment.

With reference to figure 2 the same fish farm as in figure 1 is shown, but this time in perspective of the farm under the water surface, and more details are shown. The bioreactor 6 can be arranged centrally in the fish pens 1 , and here it can be seen that under the spokes there is arranged a transport passage 7 for various pipes and cables between the central production unit 5 and the sea pens 1. Around every sea pen 1 there can be seen a infection control wall 8. In this figure one can also see well that this configuration of sea pens is optimal for placing as many as possible sea pens with as little as possible space between them. All the fish pens are alike and of the same size. This makes exchanging parts and general upkeep simple. One of each section of three sea pens are used to first place the fish in, as it arrives at the fish farm, and the fish is later, half way through the time the fish spend in the fish farm F, divided into the other two fish pens remaining in the section. One can choose which of the three fish pens in the section one wish to first place the fish in, but it is most practical to first put fish in the section closest to the central production unit, so that the other two fish pens in the section is further out from the first fish pen. Thus, a structure is obtained with N fish pens where the fish is first released to, where these N fish pens are arranged in an inner circle around the central production unit, and the remaining 2N fish pens are arranged in an outer circle outside this inner circle, and is facing the sea. This can simplify the final harvesting of the fish, since it would then occur only from the outer circle.

In accordance to the method of the present invention, following a startup phase there is continual production where all the sea pens are either filled with fish, when they are in the F time phase, or they are being cleaned after the last batch of fish and prepared for the next bath, when they are in the P time phase. But since the startup of the different sections is time delayed, an even production over time is achieved over time, where both the total bio mass in the entire fish farm and out take of fish from the farm is even over time. This is achieved by delaying the upstart of production in each fish section by introducing fish in the sea pens in the following order:

(a) introducing fish into one of the 3 fish pens in the first fish pen section

where At is given as At=T/2N and T is the total time for a production cycle in the fish farm. Under (d) step (c) is then repeated so that startup of each of the N fish pens happens with a time interval At between each startup. Thus startup of each of the N sections is delayed by an even time At between each startup. When the last section is started up, one once more wait a time At before introducing fish into one of the 3 fish pens in the first fish pen section, where“one of the 3 fish pens” is the same fish pen chosen in step (a) (the two other fish pens will be full of fish that were

transferred from the this fish pen, as will be explain in more detail below). This is then repeated after At in the second fish pen section then after At in the third fish pen section, etc., until all the fish pen sections have again been started up, and will then continue continuously and result in a continual, evenly distributed startup of the fish pens in the fish farm. After two such startup cycles all the sea pens in the fish farm will be in operation, i.e. either filled with fish or being prepared, and this is the total time for a production cycle T.

Since the fish pens must spend time P for cleaning after they are emptied of fish and is being made ready for the next batch of fish, the time for the production cycle T is shorter than the time the fish spend in the fish farm F. Half of time F is spent b the fish in a first of the third fish pens in a fish pen section, the other half in the two other fish pens in the fish pen section. The retention time in each fish pen is then approximately ½ F. Thus, the total time for a cycle T is equal the time F the fish is spending in the fish farm plus two cleaning/preparation phases P (two because both fish pens the fish is in must be cleaned): T=F+2P.

Thus, each individual sea pen section is operated as follows:

(f) after ended retention time in the first fish pen in the fish pen section the fish is moved therefrom and divided among the two remaining fish pens in the fish pen section, where they have a retention time of ½ F before they are removed from the two remaining fish pens in the fish pen section and from the fish farm, (g) when the first fish pen in the section is emptied, it is cleaned and prepared during time P, and then a new batch of fish is introduced therein,

(h) when the two remaining fish pens in the section is emptied, they are cleaned and prepared during time P and then a new batch of fish is introduced therein from the first fish pen in the section,

(i) steps (g) and (h) are repeated continuously.

This is the optimal method of production. When the parameters are being chosen therefor, one should add a little extra time for P and/or F in order to have a little leeway in case unforeseen problems arise, so a approximately even continual production can still be achieved For example, if the fish is not growing as well as it should, it may need a little extra time in the fish pens, or if there is outbreaks of disease one may need a little extra time to disinfect the sea pens. But this can be adjusted to fall within the production parameters, and possible delays have a minimal effect on the total production.

For almost all fish types and production parameters, a total retention time F in the fish farm will be between 4 and 24 months. Most fish types will have a retention time F of between 8 and 14 months, and for optimization of production, a retention time F of 11 -12 months is preferred. Most preferred is a retention time F of 1 1 months. If F is 1 1 months, and one use a time P from a fish pen is emptied for fish in order to clean and ready the fish pen until it is filled again with more fish of ½ month, one will arrive at a total time for a production cycle T of 12 months. If one also use the most preferred sea pen constellation with 6 sea pen sections with 3 fish pens in each section, one will have a continual production with harvesting fish from one sea pen section each month, and filling one fish pen section with new fish each month. One may of course also achieve a production cycle T of 12 months by shortening and lengthening P and F while T remains 12 months. If N is not 6, P and F can also be adjusted to achieve monthly harvesting, but then T will not be 12 months because one is not harvesting 12 times per time T. If one for example have only 5 sections, so that N=5, one only have 2N=10 harvests eh production cycle T. If one desire a monthly harvesting one must in that case have a T of only 10 months. This is something a skilled person in the fish farming field will be able to assess and adjust.

The tables below show several examples of production in accordance with the present invention:

Table 1 shows the time for the different production events (when the fish is moved into a new fish pen and when the cleaning phase commence), given as months from startup of the entire fish pen. Table 1 shows this for N=6 sections, C=1/2 month with cleaning and preparatory time, F=1 1 months total with retention time in the fish farm for the fish. This is equivalent to a scenario where T=12 months, and At = 1 month waiting time between the startup and harvesting of the fish pen sections. All the number in the table is thus referring to months.

Table 2 shows the time for the different production events (when the fish is moved into a new fish pen and when the cleaning phase commence), given as months from startup of the entire fish pen. Table 2 shows this for N=6 sections, C=1/2 month of cleaning and preparatory time, F=14 months total with retention time in the fish farm for the fish. This is equivalent to a scenario where T=15 months, and At = 1.5 month waiting time between the startup and harvesting of the fish pen sections. All the number in the table is thus referring to months.

Table 3 shows the time for the different production events (when the fish is moved into a new fish pen and when the cleaning phase commence), given as months from startup of the entire fish pen. Table 3 shows this for N=7 sections, C=3/4 month of cleaning and preparatory time, F=16 months total with retention time in the fish farm for the fish. This is equivalent to a scenario where T=17.5 months, and At = 1.25 month waiting time between the startup and harvesting of the fish pen sections. All the number in the table is thus referring to months.

Thus, tables 1 -3 show three different ways of carrying out the method in accordance with the present invention, that all result in an evenly spaced harvest of biomass over time. These are only examples, by adjusting the different variables one can obtain a large number of scenarios, and the production can be adjusted to the running of the fish farm in accordance with the conditions/parameter one desire.

The size of the fish pens can vary some, but in order to achieve large capacity as is the purpose of the present invention, they should be of some size. On the other hand, it is not functional if they are too large, since they then get more difficult to handle, and there are regulations for how many fish one can have in one fish pen. The upper limit is usually set because of worry of fish escaping the fish farm, i.e. one sets an upper limit on what is the maximal number of escaped farmed fish the environment can handle, and this is the limit of fish per fish pen. This is well known on the fish farm field, and thus choosing the size of the fish pens and the amount of fish is something a skilled person will know how to do An example of a practical use of the present invention is to set out 200,000 fish in one of the 3 fish pens in a fish pen section, and then as they are to be moved over into the two remaining fish pens of said section half (about 100,000 fish) is moved into each of the two remaining fish pens. When the two remaining fish pens are then harvested after ended retention time F in the fish farm, 200,000 fish is harvested from one fish pen section. An example of a practical size is that each fish pen has a diameter of 33 meters, which will mean that the central production unit will have a similar size, and the whole fish arm will have a diameter of approximately 170 meters.

Each fish pen has its own recycling system, which will lead to reduced water usage. Isolation of the fish pens, warming up water etc. for even production.

The parts comprising the spokes of the wheel that makes up the fish farm is practically separation of the fish pen sections. Preferably this will also define separate infection zones which are divided by protection walls underwater, and they will have walkways that ease the accessibility to the fish pens above water, and they will contain cable and pipe systems that lead feed and water out to the fish pens from the central production unit, and sludge in return.

The central production unit comprises the common functions for all the fish pens. Feed and water is lead out therefrom to the fish pens, and sludge from the fish pens are treated there. A common water intake will usually be placed there, and water treatment and water heating, as well as gas production The central production unit is preferably divided into several floors, where in accordance with a preferred embodiment of the invention there is placed one or more ballast tanks in the bottom thereof, so that the buoyancy can be regulated in accordance with how much feed the fish farm is storing at any given time. Thus the central production unit and the entire fish farm will float at the same level in the water all the time, i.e. lay neutrally in the water, and be stable. On the floor above the ballast tanks one may have feed silos. On the floor above the feed silos, one may preferably locate the water intake and water treatment functions. The floor on the main deck level preferably contain functions it is practical to have easy access to, such as backup power, technical room and generators. The top floors may comprise functions such as a

bridge/control room and different rooms for the use of the crew.

Figure 3 shows a cross section of the central production unit 5, here shown with ballast tanks 9 at the bottom, and several floors 10. Figure 4 shows a cross section of the central production unit 5 seen from above, in this case adjusted to a fish farm with 6 fish farm sections. The spokes 4 which continue out between the fish farm sections are shown, and the cross section shows the floor where the feed silos 1 1 are stored.

Preferably, the entire fish farm is covered by a roof, that can be covered by sun cell panels for internal supply of electricity.

Since the purpose of the invention is to obtain as continual production as possible, in accordance with a preferred embodiment thereof one will try to keep the water in the fish pens at a as even a possible temperature. This will lead to the fish growing evenly, with the same rate, so that the harvesting thereof is also even with fish of a approximately same size. In most waters that will mean that it is desired to heat up the water during large parts of the year, since this will lead to a quicker growth and larger production. This can be done more effectively by using intake water from variable depths, so that one take the water from where it is the warmest, and by isolating the fish pens, so that they can keep the heat in, and by being fully or partially self-sufficient with electricity from sun cell production units, so that the heating up of the water is practical in relation to costs, and by adding as little as possible fresh water. The latter can be done by having effective processes for water cleaning and oxygenating, so that the need for refreshing is less. It is then preferred that each fish pen has its own recycling system independent of the other fish pens, because then one still need less fresh water, and one will also have less spread of disease. The water that is taken in can preferably also be heat exchanged with water that is removed (sludge), and waste heat from own production of oxygen can also be heat exchanged with water that is taken into the system. In the coldest part of the year it may, dependent on the conditions, be necessary with heat addition via a heat pump.

Different fish species has different optimal temperatures for growth, and this must be considered in relation to costs of heating up water in order to arrive at a desired average temperature for the water in the fish pens in the fish farm. For optimal production from the fish farm in accordance with the present invention it is preferred that the temperature in the fish pens is kept at +/- 5 °C of desired temperature, preferably at +/- 3 °C for a more even production/growth of the fish, and mot preferably at+/- 2 °C. For the fish to thrive at all an outer limit of +/- 5 °C is sufficient for most types of fish. For many type of fish that are farmed, a temperature difference form the lowest to the highest temperature during the growth cycle of not more than 6°C is a good goal, for example salmon and trout is good to keep within a window of 8-12°C , or 10-16°C. Then the growth will mostly stay stable. For many fish species it is desirable for stabile growth to keep the temperature in the fish pens at +/- 3°C of the optimal temperature for said specific species, but for some more sensitive species such as tropical fish species, it may be necessary with a smaller temperature variation of +/- 2°C. It may also be desirable with a temperature window of 4-5°C for other species of fish, for a better window of thriving. Another way of expressing this is that for optimal operation in accordance with the method in accordance with the present invention it is preferable that the water temperature in the fish pens are kept stabile enough over long term operation for the fish to grow at a close to even rate. By long time operation is then meant within a year, since seasonal variations usually will be responsible for the largest temperature variations. How much variation that can be allowed for the temperature to be“stabile enough” will as discussed above vary with the type of fish. That the fish grows with“ lose to even rate” means that the growth rate of the different bathes of fish produced over time I stabile enough for the biomass production from the fish farm in accordance with the present invention to be approximately even. By keeping the water temperature in the fish pens stabile over long term operation as optimal operational and growth conditions as possible is reached, and this will lead to an optimal operation of the fish farm with a very even biomass production.

The fish farm is producing optimally when all factors, not just the water temperature in the fish farms, are kept as even as possible throughout the year. An important premise for this is the hatchery produced fish, i.e. the size thereof and that it is delivered at the right time In order to even out the results of the hatchery fish being small when being introduced to the fish farm, a couple of weeks playroom at the harvesting is desirable. Large variations in the fish size throughout the year will influence the good properties for the fish farm or add high requirements to follow up of each individual fish group.

There are no restrictions on what type of fish one can keep in the fish farm in accordance with the present invention A preferred example is production of salmon or trout, and then the most preferred segment of fish of 4 to 8 kg finished fish most preferred 7 kg salmon and somewhat less for trout. Salmond grows more poorly if it is kept at a temperature above 16 °C, 12-16 °C is ideal, within 10-12 °C the growth will be somewhat reduced and below 10°C it will be reduced. For fish farms for salmon and trout in Norway this means that one with advantage can increase the temperature in the water from the usual sea temperature. By increasing the temperature in the sea farm/sea pens faster growth is obtained. This enables lowering the total retention time F for the fish down towards 8 months if the fish is of 300 g size when being introduced and harvesting at about 7kg is desired. The maximal time F for salmon and trout is under 14 months, and this will be the case if no heat is added.

Preferably each fish pen contains a bio filter. This will primarily handle the nitrogen rich fish excrement and break it down to nitrite/nitrate. But the sludge also contains other nutrients, among them a lot of protein from feed leftovers etc.

Outside the fish pen sections one may if desired also arrange more fish pens where one is not farming fish, but other organisms which may benefit from the nutrients in the sludge from the fish pens. This can be integrated as a part of the purification of the sludge, so that less thereof must be handled. Cleaning organisms that feed on sludge or finer particles are well known on the field. Larger organisms like tunicates or shells such as mussels can also be simultaneously produced with the fish in this manner. One will then need structure in the fish pens they are to grow in that they can be affixed to, but the fish pens themselves may be of the same type as used for the fish.

The fish farm industry is regulated by the Norwegian governments with the so called MTB (maximal allowed biomass). By maintaining an even introduction of fish, and most preferably in accordance with the present invention monthly, an even biomass increase is obtained when the temperature is also even. With harvesting at the correct time the biomass can them be kept under the allowed MTB at any time and a considerable increase in production can be achieved. By using the method of the present invention one may then maintain a constant growing biomass where harvesting occurs at set times where whatever is above the allowed MTB is harvested.

Claims

1. Method for continual fish farming in a fish farm set in a body of water, characterized in that the fish farming is carried out in a fish farm comprising a number N of fish pen sections arranged in a wheel pattern, where a central production unit forms the hub, and the wheel pattern has N spokes radially evenly distributed out from the hub, where each of the N sea pen sections is arranged adjacent to two of the spokes, and each sea pen section comprises 3 sea pens, one inner sea pen arranged tangentially to the hub and two sea pens arranged outside the inner sea pen,

where the farming in the fish pens is time-lagged to achieve an even fish production over time form the fish farm, and this is achieved by delaying the start of production in each of the fish pen sections by introducing fish into the fish pens in the following order:

(a) introducing fish into one of the 3 fish pens in the first fish pen section

where F is the time the fish spend in the fish farm, and P is the time it takes from a fish pen is emptied of fish in order to be cleaned and prepared until the fish pen is again filled with fish, and

T=F+2P, and

where each individual sea pen section is operated as follows:

(g) when the first fish pen in the section is emptied, it is cleaned and prepared during time P, and then a new batch of fish is introduced therein,

(i) steps (g) and (h) are repeated continuously.

2. Method in accordance with claim 1 , characterized in that N=4-8, more preferably N=5-7, and most preferred N=6.

3. Method in accordance with one or more of the previous claims, characterized in that F=4-24 months, preferably F=8-14 months, more preferred F= 10-12 months, and most preferred F= 1 1 months.

4. Method in accordance with claim 3, characterized in that F=1 1 months, T=12 months, and P=1/2 month.

5. Method in accordance with one or more of the previous claims, characterized in that the water temperature in the fish pens is kept within a temperature variation of +/- 5°C of the desired temperature, preferably +/- 3°C, and more preferred +/- 2°C.

6. Method in accordance with claim 5, characterized in that the water temperature in the fish pens is kept stabile enough over long time production for the fish to grow at an approximately even rate.

7. Fish farm set in a body of water for continual fish farming characterized in that it comprises a number N fish pen sections arranged in a wheel pattern, where a central production unit forms the hub, and the wheel pattern has N spokes radially evenly distributed out from the hub, where each of the N sea pen sections is arranged adjacent to two of the spokes, and each sea pen section comprises 3 sea pens, one inner sea pen arranged tangentially to the hub and two sea pens arranged outside the inner sea pen.

8. Fish farm In accordance with claim 7, characterized in that N = 6.

9. Fish farm In accordance with claim 7 or 8, characterized in that the central production unit comprises water intake, water treatment, feed silos, sludge handling, operation controls, and ballast for the entire sea farm.