NO20220646A1

NO20220646A1 - Closed fish farming structure

Info

Publication number: NO20220646A1
Application number: NO20220646A
Authority: NO
Inventors: Andreas Fredborg; Henrik Hannus; Kristoffer Kjellså Jakobsen
Original assignee: Aker Solutions As
Priority date: 2022-03-03
Filing date: 2022-06-03
Publication date: 2023-09-04

Description

Closed fish farming structure

Technical field

The present disclosure relates to a fish farming structure for a closed fish farm.

Background art

The problem of overfishing and the consequences thereof have been known for many years. One solution to meet consumer demand for fish, while at the same time preserving natural fish stocks, is to operate fish farms. Such fish farms may be able to rear large quantities of fish in captivity, thereby reducing strain on natural fish stocks.

As technology relating to fish farms has developed, there has been a continual focus on safety, fish welfare and the environmental impacts of fish farming, which in turn has driven a demand for improved method and solutions for fish farming. Most often, fish farms are located near shore in coastal areas in the sea or ocean, where the fish farm can have some protection resulting from the natural landscape of fjords or archipelagos, or even in large lakes or rivers or in basins on land. In order to reduce the impact of environmental forces on a fish farm, it may be desirable or necessary to locate a fish farm in a sheltered location, where waves are likely to be smaller than in the open sea or ocean. However, in doing so, different problems may arise, for example the available space in a natural bay may be limited, and the throughflow of water may be restricted, which may place an upper limit on the possible biomass in the area with respect to oxygen and emissions. The proximity to other fish farms may also provide an increased risk of spreading diseases between fish. Therefore having the ability use a closed fish farming system would permit a user to avoid this drawback and enable fish farming in suboptimal locations and closer to other fish farms.

Conventional closed systems may be used in some cases where it is desired to have some form of isolation between the fish farm and the surrounding environment, and may also permit the collection of feed spill and other waste that is generated in a fish enclosure. Conventional closed systems may involve, for example, an enclosure formed from a flexible bag, or an enclosure formed with a rigid basin. However, conventional closed systems can be very sensitive to adverse weather conditions. Such fish enclosures may be more prone to deformation in a body of water, owing to the fact that the closed material is more affected by wave and tidal forces in a body of water, and to changes in pressure therein. Conventional closed fish enclosures can also suffer from the phenomenon of internal wave systems forming inside the fish enclosure which may be exacerbated by external wave forces, and may also exhibit less predictable hydrodynamic behaviour. All of these issues can cause damage to both the fish farm structure and to the fish therein.

Summary

It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least the above mentioned problem. According to a first aspect there is provided a fish farming structure for a closed fish farm, comprising: a floatable structure comprising a collar and an access structure; a closed fish enclosure configurable to be suspended from the floatable structure via a suspension arrangement; the collar defining an access opening therein for providing access to the fish enclosure, and the collar being configurable to be submerged in a body of water; the access structure located on the collar, and being configurable to extend from a submerged location at which the access structure connects to the collar to a location above a waterline of a body of water; the closed fish enclosure being configurable to extend above the level of the collar.

Various further inventive aspects and embodiments according to the present disclosure will now be outlined in the following A-clauses:

CLAUSE A1. A fish farming structure for a closed fish farm, comprising:

a floatable structure comprising a collar;

a closed fish enclosure configurable to be suspended from the floatable structure via a suspension arrangement;

the collar defining an access opening therein for providing access to the fish enclosure;

the closed fish enclosure comprising an upper and a lower portion, the upper portion extending between the floatable structure and a connection to a structural frame, and the lower portion extending from the connection to the structural frame to form a base of the closed fish enclosure.

CLAUSE A2. A fish farming structure according to clause A1, wherein the collar is configurable to be submerged (e.g. completely submerged) and the floatable structure comprises an access structure, the access structure located on the collar, and being configurable to extend from a submerged location at which the access structure connects to the collar to a location above a waterline of a body of water.

CLAUSE A3. A fish farming structure according to clause A1 or A2, wherein the closed fish enclosure comprises a fluid outlet for permitting flow of a fluid from the fish enclosure to a body of water, and a fluid inlet for permitting flow of a fluid to the fish enclosure from a body of water, wherein the fluid flow rate through the fluid outlet is selectably variable so as to permit raising and lowering of the water level of a water volume inside the closed fish enclosure.

CLAUSE A4. A fish farming structure according to clause A3, wherein the fluid inlet comprises an inlet conduit having an inlet positionable below the fish enclosure, and the inlet conduit having an outlet located in the fish enclosure and below the water level of a water volume inside the closed fish enclosure.

CLAUSE A5. A fish farming structure according to clause A3 or A4, wherein the inlet conduit is connected (e.g. directly connected) to the structural frame.

CLUASE A6. A fish farming structure according to clause A5, wherein the inlet conduit is connected to the frame via a sleeve that is connected to the frame, for example via a tie, a rigid or flexible connector, or the like.

CLAUSE A7. A fish farming structure according to clause A5, wherein the inlet conduit extends through the frame.

CLAUSE A8. A fish farming structure according to any of clauses A3 to A7, wherein floatable structure comprises an access structure, and the inlet conduit extends through the access structure.

CLAUSE A9. A fish farming structure according to any of clauses A3 to A8, wherein the fluid outlet comprises a fluid pump.

CLAUSE A10. A fish farming structure according to any of clauses A3 to A9, where the fluid outlet comprises one or a plurality of fluid ports located in the closed fish enclosure.

CLAUSE A11. A fish farming structure according to clause A10, wherein the fluid outlet comprises a fluid port in the upper portion and a fluid port in the lower portion.

CLAUSE A12. A fish farming structure according to any preceding A clause, wherein the closed fish enclosure comprises a waste outlet, the waste outlet optionally comprising a conduit extending from the waste outlet to a waste containment unit (e.g. a mort container or separation chamber) in or on the floatable structure.

CLAUSE A13. A fish farming structure according to any preceding A clause, wherein the collar and the frame have a circular annulus shape.

CLAUSE A14. A fish farming structure according to any of clauses A1 to A12, wherein the collar and the frame have a polygonal annulus shape, or a polygonal cross section.

CLAUSE A15. A fish farming structure according to any preceding A clause, wherein the closed fish enclosure comprises at least one flow obstructer extending into the fish enclosure, and the at least one flow obstructer is in the form of a fin.

CLAUSE A16. A fish farming structure according to any preceding A clause, wherein the closed fish enclosure comprises a plurality of sub-enclosures therein.

CLAUSE A17. A fish farming structure according to any preceding a clause, wherein the structural frame is rigid.

Various further inventive aspects and embodiments according to the present disclosure will now be outlined in the following B-clauses:

CLAUSE B1. A fish farming structure for a closed fish farm, comprising:

a floatable structure comprising a collar (and optionally an access structure);

the closed fish enclosure comprising a first enclosure and a second enclosure, an enclosed intermediate water volume being contained between the first enclosure and the second enclosure and at least one of the first enclosure and the second enclosure being a closed enclosure.

CLAUSE B2. The fish farming structure according to clause B1, wherein both the first enclosure and the second enclosure are closed enclosures.

CLAUSE B2. The fish farming structure according to clause B1, wherein the first enclosure is completely contained within the second enclosure.

CLAUSE B3. The fish farming structure according to clause B1, wherein the first enclosure is partially contained within the second enclosure, optionally wherein only an upper portion of the first enclosure is contained within the second enclosure, and a lower portion of the first enclosure is located outside of the second enclosure.

CLAUSE B4. The fish farming structure according to any preceding B clause, wherein one of the first and second enclosures is water permeable, and one of the first and second enclosures is water impermeable.

CLAUSE B5. The fish farming structure according to any of clauses B1 to B3, wherein both of the first and second enclosures are water permeable.

CLAUSE B6. The fish farming structure according to any preceding B clause, wherein the fish enclosure comprises at least a third closed fish enclosure.

CLAUSE B7. The fish farming structure according to clause B6, wherein both the first fish enclosure and the second fish enclosure are contained within the at least third fish enclosure.

CLAUSE B8. The fish farming structure according to any preceding B clause, wherein the first fish enclosure comprises an upper and a lower portion, the upper portion extending between the floatable structure and a connection to a structural frame, and the lower portion extending from the connection to the structural frame to form a base of the closed fish enclosure.

CLAUSE B9. The fish farming structure according to any preceding B clause, wherein the second closed fish enclosure comprises an upper and a lower portion, the upper portion extending between the floatable structure and a connection to a structural frame, and the lower portion extending from the connection to the structural frame to form a base of the closed fish enclosure.

CLAUSE B10. The fish farming structure according to any preceding claim, wherein the second closed fish enclosure comprises a tether, the tether being optionally releasable, to the first closed fish enclosure extending through the enclosed water volume contained between the first closed enclosure and the second closed enclosure.

CLAUSE B11. The fish farming structure according to any preceding B clause, wherein the water volume of the first closed fish enclosure has a higher pressure than the water volume of the second closed fish enclosure.

CLAUSE B12. The fish farming structure according to any preceding B clause, wherein the first closed enclosure comprises an outlet, and the second closed enclosure partially encloses the first closed enclosure around the periphery of the outlet.

CLAUSE B13. The fish farming structure according to any preceding B clause, wherein the first closed enclosure comprises an outlet, and the fish farming structure comprises a circulation arrangement for circulating water from the first closed fish enclosure to the second closed fish enclosure (e.g. into the intermediate water volume).

CLAUSE B14. The fish farming structure according to clause B14, wherein the circulation arrangement comprises a water inlet, optionally supported by the floatable structure, to fluidly connect a source of water to the first closed enclosure.

CLAUSE B15. The fish farming structure according to any preceding B clause, wherein the second closed enclosure comprises a sump at the base thereof, for collecting detritus from the first closed enclosure, optionally via an outlet in the first closed enclosure.

CLAUSE B16. The fish farming structure according to any preceding B clause, wherein the intermediate water volume comprises a waste removal arrangement for removing waste from the intermediate water volume.

CLAUSE B17. The fish farming structure according to clause B16, wherein the waste removal arrangement comprises at least one, or a combination of, a gas diffusor, a surface foam skimmer, a sump, a sediment removal conduit, or the like.

CLAUSE B18. The fish farming structure according to any preceding B clause, comprising a temperature control arrangement or system, wherein the second closed fish enclosure comprises a water inlet and a conduit extending from the water inlet to a location below the second closed fish enclosure, and the temperature control arrangement optionally comprising a heat exchanger for heating of water in a flowpath extending though the water inlet.

CLAUSE B19. The fish farming structure according to any preceding B clause, comprising a third closed fish enclosure, the first and second closed fish enclosures being located inside the third closed fish enclosure, and a second intermediate water volume located between the second fish enclosure and third fish enclosure, the intermediate water volume at least partially comprising a waste removal arrangement and the second intermediate water volume at least partially comprising a temperature control arrangement.

CLAUSE B20. The fish farming structure according to any preceding B clause, wherein the collar is configurable to be completely submerged.

Various further inventive aspects and embodiments according to the present disclosure will now be outlined in the following C-clauses:

CLAUSE C1. a fish farming structure for a closed fish farm, comprising:

a floatable structure;

the closed fish enclosure comprising a first enclosure and a second enclosure, an enclosed intermediate water volume being defined between the first closed enclosure and the second closed enclosure, the first enclosure configured to permit fluid flow to the second enclosure so as to permit fluid communication between a water volume in the first enclosure and the intermediate water volume; and

wherein the fish farming structure comprises a waste removal arrangement comprising a fluid outlet from the first closed enclosure to the second closed enclosure, and a fluid outlet from the second closed enclosure.

CLAUSE C2. A fish farming structure according to clause C1, wherein the closed fish enclosure comprises a sump at the base thereof.

CLAUSE C3. A fish farming structure according to clause C2, wherein the closed fish enclosure defines a fluid outlet at the base thereof, for removal of waste from the sump.

CLAUSE C4. A fish farming structure according to clause C2 or C3, wherein the base of the fish enclosure has at least one of: an inverted cone shape, inverted pyramid shape, partial or semi-spherical shape and a partial or semi-oblong shape, and a fluid outlet located at the base thereof.

CLAUSE C5. A fish farming structure according to any preceding C clause, wherein the fish enclosure comprises a gas diffusor therein, and a foam skimmer located at the surface of a water volume contained in the closed fish enclosure.

CLAUSE C6. A fish farming structure according to any preceding C clause, comprising a first closed fish enclosure and a second closed fish enclosure, the first closed fish enclosure being located within the second closed fish enclosure to define an intermediate water volume therebetween, the waste removal arrangement being located in the intermediate water volume.

CLAUSE C7. A fish farming structure according to clause C6, wherein a gas diffusor is located in the intermediate water volume, and a surface foam skimmer is located at the surface of the intermediate water volume.

The present disclosure will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in the detailed description that changes and modifications may be made within the scope of the disclosure.

Hence, it is to be understood that the herein disclosed disclosure is not limited to the particular component parts of the device described or steps of the methods described since such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It should be noted that, as used in the specification and the appended claim, the articles "a", "an", "the", and "said" are intended to mean that there are one or more of the elements unless the context explicitly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" may include several devices, and the like. Furthermore, the words "comprising", "including", "containing" and similar wordings does not exclude other elements or steps.

Brief descriptions of the drawings

The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.

Figure 1 shows a schematic elevation view of a fish farming structure.

Figure 2 is a perspective view of a fish farming structure.

Figures 3a to 4c are schematic plan views of various fish farming structures.

Figure 5 is another schematic elevation of a fish farming structure.

Figures 6a to 6c are schematic plan views of various examples of a fish farming structure, showing some additional features.

Figures 7a and 7b illustrate an example of a suspension arrangement.

Figures 8 to 10 show an example of a fish farming structure having a roof enclosure.

Figures 11 and 12 are examples of a closed fish enclosure.

Figure 13 is a configuration for removing mort and other waste from a fish enclosure.

Figures 14a to 14c show further examples of a fish enclosure.

Figure 15 is a further perspective view of a fish enclosure.

Figure 16 schematically illustrates the circulation of water within a fish enclosure.

Figures 17 and 18 are schematic illustrations of configurations of conduits of a fish farming structure.

Figures 19 to 24b are schematic elevations of various fish farming structures comprising a first and second enclosure.

Figures 25 and 26 illustrate circulation of water in an intermediate volume of a fish farming structure.

Figure 27 illustrates a fish farming structure having a first and second enclosure, where the one enclosure is water permeable, and one comprises a single outlet.

Figure 28 is a fish farming structure having a temperature control system.

Figures 29 to 32 illustrate examples of a protector for preventing damage to a fish farming structure.

Detailed description

The present description provides an improved fish farming structure for closed fish farm. According to an example embodiment there is provided a fish farming structure for a closed fish farm, comprising:

a floatable structure comprising a collar and an access structure;

the collar defining an access opening therein for providing access to the fish enclosure, and the collar being configurable to be submerged in a body of water;

the access structure located on the collar, and being configurable to extend from a submerged location at which the access structure connects to the collar to a location above a waterline of a body of water;

the closed fish enclosure being configurable to extend above the level of the collar.

In use, the fish farming structure may be placed in an open-water location and the closed fish enclosure suspended from the floatable structure. The collar of the floatable structure being submerged in a body of water may have a protective effect on the floatable structure and closed fish enclosure suspended therefrom, by limiting the effect of environmental forces such as surface waves on the collar, and thereby having a reduced effect on the movement of the floatable structure and fish enclosure therein. In protecting the fish enclosure from the effect of environmental forces, more flexibility may be afforded to the design on the closed fish enclosure by permitting a design in which less priority is required to be given to durability of the material of the closed fish enclosure. For example, it may be desirable for the fish enclosure to be made from a deformable material without incurring excessive cost.

In Figure 1, there is illustrated an example of a fish farming system 100 according to the present disclosure, shown in cross-sectional elevation. In this example, the fish farming system 100 comprises a floatable structure 101, which in this example is a semi-submersible structure (e.g. comprising a submerged portion, and a non-submerged portion), although in other examples may float on the surface. The fish farming system 100 of this example may therefore be considered to be a semi-submersible fish farming system.

According to this disclosure and as is understood in the art, a traditional open fish farm is one comprising an enclosure having a net, cage or similar open barrier material which is positioned in a body of water either wholly or partially below the waterline, and which functions as a barrier to prevent fish from passing therethrough and outside of the enclosure, and to prevent predators from entering the enclosure and causing a danger to the fish inside, but is but is not intended to prevent the flow of water therethrough, as well as and suspended particulate matter and microorganisms therein.

The term “closed fish farm” is also understood in the art, and refers to a fish enclosure having a net, cage or similar barrier material that provides an enhanced barrier compared to that of an open fish enclosure, in that it prevents fish and predators from passing therethrough, as well as acting as a barrier to other organisms or matter. Many types of closed fish farm exist, and may be considered to be semi-closed or fully-closed. Herein the term “closed fish farm”, “closed fish enclosure” or similar should be taken to encompass both a fully-closed and a semi-closed fish farm or enclosure unless specified or described otherwise.

A fully-closed fish farm is herein intended, as is understood in the art, to describe a farm comprising an enclosure that prevents the passage of all matter therethrough (e.g. water, detritus, parasites, pathogens, marine organisms), with the exclusion of any inlets, outlets or openings (e.g. the opening at the top of the fish enclosure) that may also form part of the fish enclosure and may be intended to permit fluids and suspended particulate matter through the barrier of the closed fish enclosure, thereby completely separating the fluid volume inside the fully-closed fish enclosure from the surrounding body of water. A fullyclosed fish farm may therefore comprise an enclosure that is water impermeable. The inflow or outflow of fluids from a fully-closed fish farm may be completely controlled by a user, for example by the opening and closing of fluid inlets and outlets to the fish enclosure. The fullyclosed fish enclosure may be or comprise a sheet or collection of connected sheets of water impermeable material, which may be a flexible fabric material, a rigid sheet of metal, or the like.

A semi-closed fish farm is herein intended to describe fish farm comprising an enclosure that provides an enhanced barrier compared to that of an “open” fish enclosure, in that it prevents not only the passage of predators and fish through the walls of the enclosure, but also other matter and organisms (e.g. microorganisms), which may include some or all of particles of fish feed, fish waste such as faeces, sea lice, marine parasites, algae, plankton, or the like, but may permit the passage of seawater and other fluids therethrough. A semi-closed material may therefore be water permeable, and may be or comprise a sheet of water permeable fabric, a finely woven net, a rigid metal sheet with perforations (e.g. pinhole perforations) therein, or a combination of such materials. In some examples, a semi-closed fish enclosure may comprise both a section that is water impermeable and a section that is water permeable. A semi-closed enclosure may be made from a combination of materials that are selected in order to provide the desired enhanced barrier. For example, a semi-closed enclosure that is desired to provide a barrier to sea lice, algae, pathogens, or the like that are found near the water surface may comprise an upper section of water-impermeable material, and a lower section of water permeable material (which may even be a standard net material in some examples), thereby permitting the passage of water into the fish enclosure, but preventing the passage of e.g. sea lice into the enclosure, which reside near the water surface.

A closed fish enclosure may be considered to be one in which the fish enclosure comprises a controlled interface in the form of a physical barrier to the surrounding body of water, to prevent the entry of marine organisms such as marine invertebrates e.g. sea lice, plankton, jellyfish, algae, pathogens, detritus or the like., and also to contain fish waste particles and uneaten fish feed, such that it can be released from the closed enclosure in a controlled manner. In contrast to conventional fish enclosures which comprise a net or cage as means to contain fish therein and to exclude predators, a closed fish enclosure comprises additional control at the boundary between the fish enclosure and the surrounding body of water, so as to additionally restrict passage of e.g. feed and waste therethrough, which may be removed from the fish farm in a controlled manner by a user (e.g. by pumping water out of the fish enclosure, opening a fluid outlet in the enclosure, or the like) and/or parasites, pathogens, algae, or the like as previously described.

The floatable structure 101 comprises a collar 102 and an access structure 108 located on the collar, and in this example from which a fish enclosure 104 is suspended via a suspension arrangement 106. The fish enclosure 104 comprises a plurality of connection points via which the suspension arrangement 106 is able to connect to the floatable structure 101 (e.g. the access structure 106 of the floatable structure 101). The collar 102 may be a buoyant collar and/or the access structure 108 may be a buoyant access structure 108.

Unless otherwise stated, the term “buoyant” should be understood to mean positively buoyant.

Suspending the closed fish enclosure 104 via a suspension arrangement 106 may assist to keep the closed fish enclosure at a desired elevation with respect to the floatable structure 101, and may offer a degree of damping of the transfer of movement between the closed fish enclosure 104 and the floatable structure 101, for example as a result of environmental forces acting upon the floatable structure 101.

Having a closed fish enclosure may offer many benefits. For example, algae, pathogens and lice that thrive near the water surface, for example due to access to sunlight and oxygen and because of proteins and fats that are more abundant at the water surface, may be prevented access to the closed fish enclosure 104, and therefore the fish enclosure 104 may act as a physical barrier. As illustrated, the fish enclosure 104 extends such that a portion thereof (e.g. at least a portion thereof) is located above the collar 102, and in this example above a waterline 105. The closed fish enclosure 104 may therefore be able to enclose a volume of fish and water therein, without risk of the fish escaping from the fish enclosure 104. Explained in further detail in the following paragraphs, the closed fish enclosure may comprise a roof enclosure, which may partially or fully cover an upper or top opening in the fish enclosure 104. The roof enclosure may serve both to protect fish inside the fish enclosure 104 from surface dangers such as aerial predators, and may also serve to prevent fish from escaping from the enclosure 104.

Although not illustrated in this example, mooring lines may be connected to the floatable structure 101 (e.g. to the collar 102 or the access structure 108) to hold the floatable structure 101 in a desired location. The mooring lines may be arranged in a frame mooring or an independent mooring system.

In some examples, the floatable structure 101 (e.g. the collar 102 and/or the access structure 108) may comprise at least one buoyancy member as part of the structure or connected thereto, for example tied or bolted thereto. In some examples, the floatable structure 101 (e.g. the collar 102 and or the access structure 108) may comprise a plurality of buoyancy members connected thereto, for example two, three, four or more buoyancy members. The at least one buoyancy member may be in the form of a closed void or air-filled compartment which may be in the form of a tank comprising an opening (optionally with a valve located therein) for permitting entry and exit of a fluid (e.g. water) therefrom.

Additionally or alternatively, the at least one buoyancy member may comprise a buoyant material, such as a buoyant foam or cellular material. In some examples, the entire collar 102 may be considered to be a floater. For example, the collar may be hollow or comprise a cavity therein providing buoyancy to the collar 102, and that is able to be filled and emptied of air and/or water if desired, e.g. the collar 102 may be able to be ballasted (as will be described in further detail in the following paragraphs). In some examples, the buoyancy of the floatable structure may be provided entirely or partially by the access structure 108.

The collar may comprise perforations (e.g. apertures, slots, or the like) therein, or comprise one or more perforated portions, for example the collar 102 may comprise a portion thereof that comprises a grate or truss structure. Having one or more perforated portions may permit water to flow through the collar 102, thereby reducing the impact of water currents and waves on the collar, and permitting self-adjustment of the buoyancy of the collar 102 by permitting water to flow into and from the collar as it rises above and falls below the waterline (e.g. flow under the force of gravity or a differential in relative density between, air and water).

The floatable structure 101 (e.g. the collar 102 of the floatable structure 101) may be rigid. Having a rigid floatable structure 101 may greatly reduce or remove the deformations of the floatable structure 101 as a result of wave motion. Reducing the deformations of the floatable structure 101 may similarly reduce deformations and load concentrations on an attached fish enclosure, thereby having a protective effect on the fish enclosure (as compared to an example in which the floatable structure was flexible, for example).

In this example, the access structure 108 extends above a waterline 110, while the collar 102 is fully submerged (i.e. substantially all the collar 102 is located below the waterline). The floatable structure 101 therefore comprises a submerged portion (the collar 102 and a lower section of the access structure 108) and a non-submerged portion above the waterline (an upper section of the access structure 108) and therefore the floatable structure 101 can be considered to be a semi-submersible structure. As is illustrated, the collar 102 is completely submerged, and in some examples at least part of the collar 102 may be configurable to be located above the waterline, for example at least temporarily (such as during maintenance and inspection of the collar 102). In some examples, the floatable structure 101 may float on the waterline, and neither the access structure 108 nor the collar 102 may be fully submerged. In such examples, the floatable structure may not be considered semi-submersible, and may be considered a surface-floatable structure, wherein the collar 102 floats on the surface of the body of water. The floatable structure 101 may be configurable between a submerged and a non-submerged configuration. The submerged configuration may be an operational draft of the floatable structure 101, while the non-submerged configuration may be considered to be a temporary or maintenance draft of the floatable structure 101. The floatable structure 101 may be configurable between a first and a second draft, which may be the operational draft and maintenance draft.

In one example, an upper surface of the collar 102 may typically be located 3 metres below the waterline 110, while a lower surface of the collar 102 may typically be located 6 to 9 metres below the waterline 110. This should be considered one example embodiment; other embodiments could be significantly deeper or significantly shallower. The actual depth of the upper and lower surfaces of the collar may vary depending on the size of the cage, the expected environmental conditions, and the desired hydrodynamic properties of the floatable structure 101. As the access structure 108 extends above the waterline, a user may be able to use this structure to locate the fish farm 100 and also to access another part of the fish farm 100 (e.g. via a communication line, winch etc.). In some examples, such as those described in the following paragraphs, a user may be able to mount or board the part of the access structure 108 that extends above the waterline. For example, a user may be able to board/mount the access structure 108 to facilitate access to another party of the fish farm 100 (e.g. an enclosure or apparatus thereof). Additionally, having the collar 102 completely submerged may reduce the magnitude of forces acting on the suspension arrangement 106 due to external forces, such as wave motion. The reduced water plane area from access structures 108 compared to the collar 102 will change the motion response of the floatable structure 101. For example, motion of the submerged collar 102 may be reduced (and may also be damped) compared to that of a collar that floats on the surface, for example because forces from wave motion on the floatable structure 101 diminish with depth, and will therefore be lesser on submerged parts of the structure.

Further, the floatable structure 101 may comprise a self-ballasting arrangement, for example comprising at least one self-ballasting structure (e.g. in the form of a container or tank) with openings therein which will be filled with water when submerged. The selfballasting structure may be in the form of a soft tank. The self-ballasting structure may be or comprise an open cavity, compartment or the like that is able to be filled with water via an aperture therein, once the self-ballasting structure is submerged below a waterline. The at least one self-ballasting structure may be located on the collar 102 or the access structure 108, and in some examples there may be a plurality of self-ballasting structures. In such examples, having the collar 102 at a submerged location will effectively increase the mass of the floatable structure 101 by permitting the self-ballasting structures to fill with water, and therefore increase the inertia of the floatable structure 101 and reduce excitation and sudden movements of the floatable structure 101, for example caused by wave motion. This may be achieved without the need to pump fluid, as the tank will ballast naturally with a flow of water through an aperture, e.g. an open aperture. As such, having the collar submerged 102 may reduce sudden and/or jarring forces (snap loads) on the suspension arrangement 106, thereby prolonging the life of the suspension arrangement 106 and reducing the risk of sudden failure thereof.

The at least one self-ballasting structure may have an opening, or the openings, thereof blocked by a user, thereby permitting a user to choose whether the self-ballasting structures should be free to fill and empty as they are submerged, or whether the self-ballasting structures should have a fixed buoyancy. A user may therefore be able to use the selfballasting structures to vary key properties (e.g. structural properties) of the floatable structure 101 to achieve optimised hydrodynamic and stability properties that are tailored to the requirements of the fish farming system. Further, the user may minimise the required energy to change draft of the structure.

The access structure 108 may be buoyant. For example, the access structure 108 may comprise at least one buoyancy member, and/or floater as described above in reference to the collar 102. In some examples, the access structure 108 may be configurable to be buoyant, thereby providing buoyancy to the floatable structure 101. In such examples, the access structure 108 may have positive buoyancy, while the collar 102 has a positive, neutral or negative buoyancy. The access structure 108 may provide substantially all of the positive buoyancy of the floatable structure 108, or may provide a majority of the positive buoyancy of the floatable structure.

In the example of Figure 1, the access structure 108 is in the form of (one or) a plurality of columns (e.g. pillars, cylinders, or the like) extending upwardly from the collar 102. At least one, or each, of the plurality of columns may extend vertically upwardly from the collar 102, or may extend upwardly at an oblique angle to the collar 102 (e.g. relative to an upper surface, or to a circumferentially or peripherally extending axis through the centre of the collar structure). The plurality of columns of the access structure 108 may be equidistantly spaced around the collar, or may be located in a plurality of groupings of two or more columns (where the columns in each grouping are adjacently located).

In some examples, the columns of the access structure 108 may extend both above and below the collar 102, which may be provide benefits in ease of structural design or fabrication.

In having a semi-submersible fish farming system 100 as described above the area of the fish farming system 100 that intersects the waterline 105 (e.g. the water plane area) may be reduced. In some examples, only the access structure 108, which may comprise a plurality of vertically and/or obliquely oriented columns, intersects the waterline, thereby reducing the water plane area as compared to examples in which the entire collar 102 intersects the waterline. Reducing the water plane area will change the response of the floatable structure 101 in waves and reduce wave loads. For example, hydrodynamic response (natural period) in heave is governed by relationship between water plane area and total mass. For a closed system, the mass will include the entrapped water in the fish enclosure 104. With a large water plane area, the hydrodynamic mass forces on the interface between the collar and the bag (e.g. acting on and/or through the suspension arrangement 106) will be very large compared to a floatable structure 101 with small water plane area, as stiffness and mass forces are out of phase. As such, having a semi-submersible fish farming system 100 as is described will reduce the loads on the fish enclosure as a result of, for example, wave loads acting on the floatable structure 101.

The fish enclosure 104 is connected to the floatable structure 101. The fish enclosure 104 is connected to the floatable structure 101 via suspension arrangement 106. The suspension arrangement 106 extends between the floatable structure 101 and the fish enclosure 104. Here, the suspension arrangement 106 extends between a plurality of the access structures 108 and the fish enclosure 104, although in some other examples, the suspension arrangement 106 may additionally or alternatively extend between the collar 102 and the fish enclosure 104.

The suspension arrangement 106 comprises at least one elongate member in this example. Here, the at least one elongate member extends between an access structure 108 and the fish enclosure 104. The suspension arrangement 106 may be or comprise a flexible member (e.g. a flexible elongate member) such as a wire, cord, chain, rope or the like. A flexible member may have low bending stiffness, and high axial stiffness, or vice versa. In some examples, the suspension arrangement may be or comprise a rigid member (e.g. a rigid elongate member) such as a rod, pipe, rail, rack or the like, which may extend between the collar 102 and the fish enclosure 104. A rigid member may have high axial stiffness. In some examples, the suspension arrangement may comprise a combination of flexible and rigid members, for example the suspension arrangement may comprise a rigid member extending between the access arrangement 108 and the collar 102, and a flexible member extending between the collar 102 and the fish enclosure 104.

Additionally or alternatively, the suspension arrangement 106 may comprise a spring and damper system. For example, a spring and damper system may be located between the floatable structure 101 and the fish enclosure 104, for example between the access arrangement 108 and the fish enclosure 104, for example an upper edge or side of the fish enclosure 104. The spring and damper system may comprise a biasing member of any appropriate type, such as a helical spring, a pneumatic or hydraulic cylinder, or the like. In some examples, the spring and damper system may comprise an elongate member forming part of the suspension arrangement 106. In other examples, the spring and damper system provide a direct connection between the fish enclosure 104 and the floatable structure 101 without the requirement for an elongate member in the spring and damper system. The spring and damper system may connect to the floatable structure 101 and fish enclosure 104 by any appropriate means, such as by a bracket, ties, a hook member or members, or the like.

The spring and damper system may be adjustable by a user. For example, where the spring and damper system comprises a pneumatic cylinder, the air pressure therein may be able to be adjusted in order to change the damping properties thereof. In the case of a hydraulic cylinder, the size of openings therein may be able to be changed so as to adjust the damping properties.

As illustrated in Figure 1, the access structure 108 is in the form of a plurality of columns which extend from the collar 102. Here two are shown, although there may be more or fewer, depending on the design of the fish farm 100.

The vertical cross-section 120 of the collar 102 is visible in Figure 1, and in this case is rectangular, although other shapes of cross-section may be desirable. For example, the crosssection 120 may be circular, square, triangular, polynomial, or any other desired shape. The entire height of the vertical cross-section of the collar 102 is submerged, and varying the shape of the cross-section may have an effect on the hydrodynamic forces acting on the collar 102 as the fish farm 100 moves in water. The shape of the cross-section may vary along the length of periphery of the collar, or circumferentially in the case where the collar has a ring or annular shape. For example, the area and/or shape of the cross-section of the collar 102 may vary along the length of the periphery (or circumferentially) of the collar 102.

Although not illustrated, at least one of the collar 102 and the access structure 108 may comprise a ballast tank therein in some examples, which may optionally be able to be ballasted and deballasted by a user. For example, a plurality, or each, of the access structures 108 may comprise a ballast arrangement comprising at least one ballast tank that is able to be ballasted and deballasted to reconfigure the weight of the at least one ballast tank to thereby control the buoyancy of the floatable structure 101. The level of buoyancy and positioning of such ballast tanks may be selected so as to ensure that the collar 102 remains submerged at all times, and at an appropriate level below the waterline 110 (e.g.3 metres below the waterline), thereby assisting to ensure that the collar 102 obtains the desired hydrodynamic properties. Additionally, the ballast level of the ballast tanks may be decreased such that the collar 102 is no longer fully submerged, which may be useful for transport and maintenance, for example. The level of ballast in the ballast tanks may be selected by pumping surrounding seawater into and out of the ballast tanks, and may be variable by a user when desired. Each ballast tank may therefore comprise a pump and caisson, at least part of which may be located in at least one of the access structure and the collar. The user may therefore be able to vary the depth of the collar 102 below the waterline, which may permit further variability of the hydrodynamic and stability properties of the floatable structure 101.

The access structure 108 or the collar 102 may comprise a height adjustment means for raising and lowering of the fish enclosure 104 relative to the collar 102. The height adjustment means may be used to vary the length (e.g. increase or decrease) of the suspension arrangement 106. In some examples, the suspension arrangement 106 and may perform the function of a height adjustment means.

The fish enclosure 104 illustrated in Figure 1 may be made from a water permeable or impermeable material (e.g. may be a fully-closed or semi-closed fish enclsoure). In Figure 1, the fish enclosure 104 is fully-closed and is made from a water impermeable material, and contains a volume of water therein, in which fish to be farmed may be contained. As illustrated, the water level 105a of the fish enclosure 104 is located at a higher level than the waterline 105 of the surrounding body of water. Having a higher water level in the fish enclosure 104 may result in the water pressure in the fish enclosure 104 being higher than that of the surrounding body of water, thereby providing a force on an internal surface of the material of the fish enclosure 104, and permitting the material of the fish enclosure 104 to be held taught, and permitting the fish enclosure 104 to hold its shape, thereby preventing fish from colliding with the material of the fish enclosure 104, and preventing damage to the fish enclosure 104 due to excessive deformation.

Also illustrated in Figure 1, the fish enclosure 104 comprises a fluid inlet 150 and a fluid outlet 152.

The fluid inlet 150 is located on an upper portion of the fish enclosure 104. In this example, the fish enclosure 104 has an open top section. The open top section of the fish enclosure 104 forms the fluid inlet for the fish enclosure 104 in this example, however it should be appreciated that in some examples the fish enclosure 104 may have a dedicated inlet 150 defined therein.

The fluid inlet 150 of Figure 1 additionally comprises an inlet conduit 154. The inlet conduit 154 extends from the fluid inlet 150 and into the surrounding body of water. The inlet conduit 154 may extend from the fluid inlet 150 to a region of the surrounding body of water that is located below the fish enclosure. In doing so, the fluid intake 151 of the inlet conduit 154 may be positioned in clean and nutrient rich water, which may also be at more stable and desirable temperature than water at the surface. The inlet conduit 154 may therefore bring clean and nutrient rich water into the fish enclosure 104 from the surrounding body of water. The inlet conduit 154 may comprise a fluid propulsion means, such as a fluid pump e.g. a submersible fluid pump, a gas lift pump or the like, in order to propel water into the fish enclosure 104. The inlet conduit 154 may be adjustable in length (e.g. may be telescopic, may comprise, or be suitable for attachment to, an extension section, or the like), and therefore the fluid intake 151 may be repositionable within a surrounding body of water, which may assist to bring water from a desired depth (e.g. and therefore at a desired temperature) into the fish enclosure 104.

The outlet 152, although not illustrated, may be similarly connected to an outlet conduit. The outlet conduit may extend at least one of vertically and horizontally, or may extend both horizontally and vertically, and may assist to deposit water flowing from the fish enclosure 104 at a location further away from the fish enclosure (or further away from the intake 151) than would be the case without an outlet conduit. The outlet of the outlet conduit and the intake 151 of the inlet conduit 154 may be positioned at a minimum predetermined distance, so as to prevent or reduce the volume of water flowing from the outlet 152 and returning through the inlet 150. For example, the depth of the fluid intake 151 may be increased, while the outlet conduit may extend in a horizontal distance and away from the fluid intake 151 so as to maximise the distance between the fluid intake 151 and the outlet of the outlet conduit. The intake 151 and the outlet of the outlet conduit may be variable in position. As such, having an inlet conduit 154 and optionally an outlet conduit may assist a user to reduce accidental recirculation of water from the outlet and back into the fish enclosure 104, and therefore improve hygiene standards within the fish enclosure 104.

The inlet conduit 154 may be supported by the floatable structure 101. The inlet conduit may be, for example, supported by at least one of the access structure 108 and the collar 102 of the floatable structure 101. The inlet conduit 154 may be attached and/or connected to the floatable structure 101, for example the access structure 108 and/or collar 102 thereof. As shown in this example, the inlet conduit 154 extends through the floatable structure 101 – here through both the collar 102 and access structure 108, although it should be understood that the inlet conduit 154 may extend through either of the collar 102 and access structure 108. Although not illustrated, the floatable structure 101 may comprise a water treatment module therein, which may be able to treat the water flowing in the inlet conduit 154. For example, the water treatment module may comprise an inlet to the inlet conduit 154 through which treatment fluids such as disinfectant, water purifying chemicals, or the like, are able to be introduced.

The fluid outlet 152 is located on a lower portion of the fish enclosure 104. In this example, the fluid outlet 152 is located at the lowermost point, or base, of the fish enclosure 104. The fluid outlet 152 is in the form of an aperture formed in the material of the fish enclosure 152. The fluid outlet 152 may be surrounded by a reinforced portion of material, for example to increase the toughness of the fish enclosure 104 and prevent propagation of tears in the material of the fish enclosure 104. Having the fluid outlet 152 at the base of the fish enclosure 104 may assist to expel detritus such as feed particles or fish waste from the fish enclosure 104 that naturally sink towards the base of the fish enclosure 104.

Here, the fish enclosure 104 has a parabolic cross-sectional shape, which may assist in an even force distribution throughout the material of the fish enclosure 104. The parabolic shape may also assist to define a base (e.g. at the lowest point thereof) at which a fluid outlet may be positioned.

In some examples, at least one or both of the inlet conduit 154 and fluid outlet 152 may be in fluid communication with the surrounding body of water. In some examples, both the inlet conduit 154 and fluid outlet 152 may be in fluid communication with a vessel or processing plant (in the case of the fluid outlet 152 via a conduit). In this case, there may be no water exchange between the surrounding body of water and the fish enclosure 104, and as such the structure 100 may be considered to be a Recirculating Aquaculture System (RAS).

Figure 2 illustrates a further example of a fish farming structure 100. Similar to the previous example, the fish farming structure 100 comprises a floatable structure 101 comprising a collar 102 and a plurality of access structures 108. A fish enclosure 104 is suspended from the floatable structure 101, in particular from the plurality of access structures 108 thereof, as will be described in more detail in the following paragraphs.

Here, the collar has a vertical cross-section in the shape of an octagon, and may be considered to have an octagonal annulus shape. Here, an access structure 108 is located at each apex of the collar 102, although in other examples an access structure 108 may be located between apexes on the collar 102, or in the case where the collar has no apexes (e.g. is a circular or oblong shape) then the access structures 108 may simply be located on the collar 102 at desirable locations.

In both Figure 1 and Figure 2 is illustrated at least one inlet conduit 154 that the fish farming structure 100 may comprise. In Figure 1, the fish farming structure 100 may comprise one single inlet conduit 154, while in this example the fish farming structure comprises one inlet conduit 154 per two access structures 108, which here is four inlet conduits 154. The inlet conduits 154 of Figure 2 are arranged on every other access structure 108 of the floatable structure 101, in an alternating manner such that they are evenly distributed around the floatable structure 101. In both Figures 1 and 2, each inlet conduit 154 is supported by an access structure 108. The inlet conduit 154 in Figure 1 extends through the access structure 108 in a vertical direction, in line with, or parallel to, the longitudinal axis of the access structure 108. In Figure 2, the inlet conduit 154 extends in a horizontal direction through the respective access structure 108, e.g. perpendicular to the longitudinal axis of the access structure 108. In some examples, the inlet conduit 154 may extend through the access structure 154 at an oblique angle. The angle with the longitudinal axis of the access structure 108 through which the inlet conduit 154 extends may be selected depending on the level of support required of the inlet conduit 154, which may vary depending on the rigidity of the inlet conduit 154, and therefore this variable may enable more flexibility in the design of the floatable structure 101.

In both Figures 1 and 2, the inlet conduit 154 extends from the access structure 108 in a downwards direction towards the fish enclosure 104, e.g. downwards towards the fish enclosure 104 and positioned radially within the collar 102. In Figure 1, the inlet conduit 154 extends downwardly at an angle perpendicular to the water level 105a of the fish enclosure 154. In Figure 2, the inlet conduit 154 comprises a first and a second downwardly extending portion. The first downwardly extending portion extends at an angle perpendicular to the water level 105a, while the second downwardly extending portion extends at an angle oblique to the water level 105a. The water exits the inlet conduit 154 from the second portion, flowing at an oblique angle to the water level 105a, which may induce a circumferentially directed flow of water in the fish enclosure 104 (relative to a vertically extending central axis of the fish enclosure 104). Having a circumferentially directed flow may provide benefits to the fish enclosure 104, for example by ensuring a high degree of water circulation throughout the entire fish enclosure 104, which assists to ensure high water quality and provides good exercise for the fish inside. In some examples, it may additionally encourage particulate matter to gather in a particular region of the fish enclosure 104, which may be near the outlet 152, and therefore may assist to further provide better hygiene within the fish enclosure 104.

The access structures 108 in Figure 2 are illustrated as being equidistantly located on the collar, although it should be noted that other configurations of access structures 108 may be possible. The illustrated access structures 108 of Figure 2 are in the form of columns having a polygonal cross-section (e.g. square, pentagonal, hexagonal, heptagonal, octagonal, or the like), which may assist in the construction of the columns, for example from panels welded together. In other examples, the access structures 108 may have a circular cross-section.

The fish enclosure 104 in this example has a horizontal cross-section that is identical in shape to the horizontal-cross section of the collar 102 of the floatable structure. In this example, an octagon. Here, as the fish enclosure 104 is suspended from each of the plurality of access structures 108 via the suspension arrangement, the suspension arrangement 108 and floatable structure 101 may assist to hold the fish enclosure in a desired shape, here having the octagonal cross-section. This configuration may additionally enable ease of access of the inlet conduit 154 to the fish enclosure 104, as the suspension arrangement 106 may hold the fish enclosure close to each access structure 108, which may support an inlet conduit 154.

In Figures 3a-c and 4a-c are illustrated various configurations of a fish farming structure 100 shown from above. In Figures 3a-c, a fish enclosure 104 having a circular cross section is shown, regardless of the shape of the respective floatable structure 101.

As illustrated in Figures 3a, 3b, 4a and 4b, the collar 102 of the floatable structure 101 comprises a square annulus shape, while in Figures 3c and 4c the collar comprises a polygonal annulus shape (specifically an octagonal annulus shape). Other shapes may be possible, such as a circular annulus shape.

As previously described, each fish enclosure 104 is suspended from the floatable structure 101 via a suspension arrangement 106. In each of Figures 3a-c (and also in Figures 4a-c), a suspension arrangement extends between the fish enclosure 104 and each of the access structures 106. In some cases, the suspension arrangement comprises one single connection member (e.g. a rope, chain, cord or the like) extending between an access structure 106 and the fish enclosure 104, and in other cases, the suspension arrangement 106 comprises a plurality (e.g. two) connection members extending between the fish enclosure 104 and the access structure 106.

In Figures 4a-c, as in Figure 2, the cross-sectional shape of the fish enclosure 104 is the same as that of the floatable structure 101 (e.g. the collar 102 of the floatable structure 101).

As can be seen in Figure 3b and 4b, the floatable structure 101 illustrates an example in which an access structure is located at each apex of the collar 102, and also between the apexes of the collar 102, in this example at a midpoint of each straight edge of the collar 102, extending vertically from the collar 102. In this example, each of the access structures 106 has a circular cross-section.

In Figures 3c and 4c, the collar 102 has an octagonal shape, whereas in Figures 3a-b and 4a-b, the collar has a square shape.

The collar 102 may be formed from one continuous member, e.g. one continuous ringshaped member. In another example, the collar 102 may be formed from a plurality of members, e.g. elongate structures, which may be connected together to form the collar 102. The plurality of structures may be a plurality of straight elongate structures, a plurality of curved elongate structures, or a mixture of at least one straight and at least one curved elongate structure. At least one of the structures may comprise perforations, in some examples, at least one, or each, of the structures may comprise a truss structure. The collar 102 may be in the form of a pontoon, or a plurality of connected pontoon members. The collar may comprise at least one buoyancy member e.g. located therein or defined thereby, which may be integrated within the or a member that forms the collar 102, or which may be connected or fastened to the member that forms the collar 102. The at least one buoyancy member may be integrally formed with the collar 102, such that it may be considered to be a buoyant collar.

Figure 5 illustrates a further example of a fish farming structure 100. The fish farming structure 100 is similar to that of Figure 1, although the structure 100 of Figure 5 comprises a support structure 111, which extends between the access structures 108 of the floatable structure 101. The support structure 111 may be in the form of a beam, connector, or the like, and may be rigid. In the example of Figure 5, the support structure may function as a hang-off for the fish enclosure 104, and may be used instead of, or as well as, the access structures 108 to suspend the fish enclosure 108 from the floatable structure 101. In this example, the suspension arrangement 106 extends between the support structure 111 and the fish enclosure 104, although in some other examples the suspension arrangement may additionally extend between an access structure or structures 108 and the fish enclosure 104. The suspension arrangement 106 may comprise a plurality of connection members extending between the support structure 111 and the fish enclosure 104. The support structure 111 may comprise a plurality of connection points onto which the suspension arrangement 106 may be able to connect.

The support structure 111 may extend between each of the access structures 108, and may have a similar shape to the collar 102.

Figures 6a-c illustrate examples of a support structure 111 on a floatable structure 101, as viewed from above. In Figure 6a, it can be seen that the support structure 111 has a square shape, which is the same as the shape of the collar 102. In this example, the support structure 111 has a larger length and width compared to the collar 102, and therefore is positioned outwardly of the collar 102.

In Figure 6b, the support structure 111 comprises two support members. Each of the two support members extends between two of the access structures 108, and in this example the support members and separate (e.g. not connected) to one another. Here, the support members extend across the opening of the fish enclosure 104, and the opening in the collar 102. Here, the support structure 111 may form a walkway, to enable a user to traverse between access structures.

The support structure 111 of Figure 6c comprises two support members. One of the support members is an octagon, which is the same shape as the collar 102, while the other of the support members extends between two access structures 106 across the opening in the fish enclosure 104. As such, in the example of Figure 6c, the support structure 111 may be able to be used as both a hang-off for the fish enclosure 104 and as a walkway.

Figures 7a and 7b illustrate an example of the suspension arrangement 106 in further detail. The suspension arrangement 106 may be at least partially located on the access structure 108 e.g. at least one component of the suspension arrangement 106 may be located on the access structure. The suspension arrangement 106 may comprise one, or a plurality of, connection members 106a that correspond to each access structure 108. In this example, the suspension arrangement 106 comprises two connection members 106a corresponding to the illustrated access structure 108.

The connection members may be a rope, chain, cord or the like. In some examples, for example where the connection members 106a are metal cords, the connection members may have high axial stiffness which may provide a secure connection with little effect from factors such as material creep, while in other examples, the connection members may be made from rope or a material with a lower axial stiffness, which may have a smoothing effect on motion transferred between the access structure 108 and the fish enclosure 104. A combination of high and low axial stiffness connection members 106a may be used.

The connection members 106a of the suspension arrangement 106 may extend between the floatable structure 101 (e.g. the access structure 108 thereof) in a vertical parallel direction relative to the longitudinal axis of the access structure 108, or may extend in a perpendicular direction or oblique direction relative to the longitudinal axis of the access structure 108. In this example, the connection members 106a extend in a perpendicular direction between the fish enclosure 104 and the floatable structure 101.

The suspension arrangement of this example comprises a pulley 156, and a connection member 106a of the suspension arrangement 106 connects to the fish enclosure 104 via the pulley 156. This may assist to further provide damping of relative motion between the fish enclosure 106 and the floatable structure 101 by permitting the connection member 106a to be fed through the pulley 156 when there is tension in the connection member 106a. It may further enable a user to control the elevation of the fish enclosure 104 relative to the floatable structure 111 by permitting the connection member 106a to be fed through the pulley to raise and lower the fish enclosure relative thereto. It should be noted that there is no requirement for the suspension arrangement 106 to comprise a pulley 156, and in some examples the connection members 106a may connect to the access structure via another means, such as through a loop of metal located on the access structure 108.

In this example, the suspension arrangement 106 comprises two connection members 106a that connect to each access structure 108. Each connection member 106a comprises a pulley 156, such that in this example each access structure 108 has a first and a second pulley located thereon, which correspond to a first and second connection member 106a. The first and second connection member 106a each connect to the fish enclosure 104 at a connection point. The connection points of each may be separate, such that the suspension arrangement 106 at each access structure 108 comprises a first and second connection point. The first connection point may be located higher on the fish enclosure 104 than the second connection point.

In locating the suspension arrangement 106 on the access structure 108, the suspension arrangement 106 may be accessible to a user even when the floatable structure 101 is partially submerged. The floatable structure may be raised, for example to a maintenance draft, so as to expose more of the suspension arrangement to a user.

In Figure 8, the fish farming structure 100 is illustrated comprising a roof enclosure 158. The roof enclosure 158 may be used to prevent predators such as aerial predators from accessing the fish enclosure 104. The roof enclosure 158 may extend across substantially the entire top surface of the fish enclosure 104. The roof enclosure may be of the same shape as the horizontal cross-section of the fish enclosure 104. The roof enclosure may be made from the same material as the fish enclosure 104 (e.g. a water permeable or impermeable material), or may be of a different material compared to the roof enclosure 158, such as a more loosely woven net material.

The roof enclosure may comprise an aperture 160 or apertures therein. The aperture or apertures 160 may function to permit feedthrough of conduits, cabling or the like. In the example of Figure 8, the aperture 160 functions to permit feedthrough of an inlet conduit 154.

Illustrated in Figures 9a-c is the connection between the roof enclosure 158 and the floatable structure 101. The suspension arrangement 106 may be configured to additionally suspend the roof enclosure 158 from the floatable structure 101, such as from the access structure 108 of the floatable structure 101. The roof enclosure 158 may be in physical contact with the fish enclosure 104, or may be suspended above the fish enclosure 104 such that there is an air gap between the roof enclosure 158 and the fish enclosure 104.

The suspension arrangement may be configurable to connect the roof enclosure to one, some or each of the access structures 108. As illustrated, the suspension arrangement 108 connects the roof enclosure to a top surface of the access structures 108.

In Figure 9a, each of the access structures comprises a horizontal protrusion 162. The horizontal protrusion 162 is located at an upper part of the access structure 108, in this example at the top of the access structure. The horizontal protrusion 162 comprises a base that is connected to the access structure 106 and an oppositely disposed tip. The horizontal protrusion protrudes perpendicularly relative to the longitudinal axis of the access structure 108. A connection member 106a of the suspension arrangement 106 extends from the access structure 106 and along the horizontal protrusion in the direction of the protrusion, until the tip of the protrusion. The connection member 106a extends from the tip of the protrusion 162 and towards the roof enclosure 158. In having a horizontal protrusion, the connection member 106a is able to extend vertically downwardly to connect to the roof enclosure, which may reduce tension of the roof enclosure at the connection points to the suspension arrangement 106. The length of connection member that extends between the tip 162 and the roof enclosure 158 may be able to be lengthened or shortened by pulling or releasing a section of connection member 106a from the top of the access structure 108. To facilitate movement of the connection member 106a relative to the access structure 108, a wheel or pulley may be positioned on the access structure 108, such as at the tip of the horizontal protrusion.

In Figures 9b and 9c, a configuration of suspension arrangement 106 is illustrated that is similar to that of Figures 7a and 7b. Here, the access structure 108 does not comprise a horizontal protrusion, and the suspension arrangement comprises a first connection member 106a that connects via a pulley 156 in a direction perpendicular to the longitudinal axis of the access structure 108. In addition, the suspension arrangement comprises a second connection member 106b that extends at an oblique angle relative to the longitudinal axis of the access structure 108, and also connects the roof enclosure 158 to the access structure 108. In Figure 9c the suspension arrangement 106 is illustrated as comprising a connection to the fish enclosure 106 located below the connection to the roof enclosure 158 on the access structure 108.

A further example of a roof enclosure 158 is illustrated in Figure 10. This roof enclosure 158 may be connected or attached to the floatable structure 101 as previously described. In this example, the roof enclosure 158 comprises a dome shape. The roof enclosure 158 may comprise support means in order to maintain such a dome shape. Here, the roof enclosure 158 is inflatable. Inflation of the roof enclosure 158 may hold the material of the roof enclosure 158 taught, thereby providing the illustrated dome shape. The shape of the material may be formed such that when it is taught, it naturally forms a dome shape. The material of the roof enclosure may be the same as the material of the fish enclosure 104.

The roof enclosure 158 may comprise a cavity or a plurality of cavities therein, which may be airtight. The cavity or plurality of cavities may be inflated so as to provide tension in the material of the roof enclosure. The roof enclosure 158 may comprise a layer of inflatable material (e.g. two layers of airtight material with a cavity therebetween), contained between two layers of an alternative material, which may be the water impermeable or permeable material of the fish enclosure.

The described roof enclosure 158 may be detachable from the floatable structure 101, for example to provide access to the fish enclosure. The inflatable roof enclosure 158 may be detachable in an inflated configuration, which may assist in the detachment of the roof enclosure 158 by providing it a degree of rigidity, or by reducing its flexibility. The inflatable roof enclosure 158 may be particularly effective when it is desirable to maintain a desired water temperature in the fish enclosure 104, by keeping colder or warmer atmospheric air away from the top of the fish enclosure 104.

Figure 11 illustrates an example of a fish enclosure 104 in more detail. While the material of the fish enclosure may be homogenous (e.g. made from one type of material), in some examples the fish enclosure may be comprised of a plurality of different materials. In Figure 11, the fish enclosure 104 may be comprised of a plurality of materials. In this example, the fish enclosure is comprised of a first material and a second material. The first material is a water impermeable material, and the second material is a water permeable material.

The first water impermeable material may comprise a bottom or lower portion of the fish enclosure 104, while the second water permeable material may comprise a top or upper portion of the fish enclosure 104, and may extend above the waterline 105 in normal operation. The first material may be configurable to be located below the waterline 105, or largely located below the waterline 105, while the second material may be configurable to be located above the waterline (e.g. entirely above the waterline) during normal use of the fish enclosure 104. As such, during normal operation, the surrounding water, as well as any macroscopic organisms therein, may be prevented from entering the fish enclosure 104 through the first material. Water, however, may be able to pass through the upper portion of the fish enclosure 104 that is located above the waterline.

In having a fish enclosure 104 that is comprised of a first and second material as described, water may be able to escape from the fish enclosure 104 through the upper portion thereof. This may be useful in the case where a large wave causes excess water to enter the fish enclosure, or in the case where the water outlet from the fish enclosure becomes blocked, as it will automatically prevent the fish enclosure from overflowing over the top of the fish enclosure which may risk fish escape, or of the water pressure in the fish enclosure 104 becoming too high and damaging the material thereof.

The example of Figure 12 is another in which the closed fish enclosure 104 comprises both a first and a second material. In this example a midsection of the fish enclosure 104, which may be configurable to be submerged during normal operation, may be made from a water permeable material, while an upper and a lower portion may be made from a water impermeable material. As the fish enclosure 104 is a closed fish enclosure, the submerged midsection (although water permeable) may still prevent the passage of macroscopic organisms therethrough.

The midsection, being water permeable, may permit a flow of water from the surrounding body of water through the fish enclosure 104, thereby reducing load on pumps that may be required to pump water through water inlet, illustrated in Figure 12 by arrows 164, and permitting the fish enclosure 104 access to water from the surrounding body of water in times of inactivity of the pumps (e.g. due to maintenance, a blockage in the inlet our outlet, or the like).

The lower section, made from a water impermeable material, may have a conical shape (as also illustrated in previous examples) which may assist to direct waste, detritus or other particulate matter towards a water outlet, which may be located at the base, which may be considered to be the apex of the conical lower section. Once at the outlet, the waste may be released to the surrounding body of water, or may be processed. Having the option to process the waste may provide a more environmentally friendly solution to waste disposal, and in some instances may be necessary, for example due to local regulations.

Figure 13 illustrates a configuration for removing mort and other waste from a fish farming structure 100, which is similar to that described in Figure 2. Here, the fish farming structure 100 comprises a waste removal arrangement 166 comprising a waste removal conduit 168, which may extend from the base of the fish enclosure 104 to the floatable structure 101, in some examples an access structure 108 thereof. In this example, the waste removal arrangement 166 is located (e.g. fully or at least partially located) inside an access structure. The waste removal conduit 168 may extend through the fish enclosure 104. The waste removal conduit 168 may extend from an outlet in the fish enclosure 104. The waste removal arrangement 166 may be considered to be, or to form part of, a mort collection arrangement.

The waste removal conduit 168 extends to a separation chamber 170 located in the floatable structure 101, in this example in the access structure 108, but may be located in the collar 102, for example. The floatable structure 101 may comprise a waste inlet 172 for receiving the waste removal conduit 168, and providing access to the separation chamber 170. The separation chamber 170 may be completely contained within an access structure 108. The separation chamber 107 receives fluid flow from the fish enclosure 104, and the fluid collects in the separation chamber 107. The separation chamber may comprise a sump for allowing particulate matter to settle out of the fluid in the separation chamber and collect in the base thereof. The sump may be located at the base of the separation chamber, and may be the shape of an inverted cone or pyramid.

The separation chamber 170 may additionally comprise a waste outlet 174, and a waste outlet conduit 176 for removal of waste from the separation chamber 170. Here, the waste outlet conduit 176 comprises a fluid propulsion means 178 such as a fluid or centrifugal pump for removing water from the separation chamber 170 to an external location. The water may be pumped directly into the surrounding body of water, or may be pumped to a vessel, platform, processing plant or the like for further processing.

The waste inlet 172 and waste outlet 174 may comprise a pressure seal so as to create a pressure sealed separation chamber 170. As such, operation of the fluid propulsion means 178 may create a suction within the separation chamber 170, and at the inlet to the waste removal conduit 168, thereby removing the need for the waste removal conduit 168 to have a dedicated pump associated therewith, or comprised therein. Alternatively, the waste removal conduit 168 may be configured to extend below a water level inside the separation chamber 170. As such, removal of fluid from the separation chamber 170 may similarly create a suction at the outlet and inlet of the waste removal conduit 168.

In some examples the waste removal conduit may comprise a gas lift pump, to encourage a flow of water therethrough.

In some examples, the waste outlet 174 and/or waste outlet conduit 176 may comprise fluid purification means, such as a chemical (e.g. chlorine) injection point, to purify water flowing from the waste outlet 174.

According to a further example, there is provided a fish farming structure for a closed fish farm, comprising:

a floatable structure comprising a collar;

Figures 14a-c illustrate an example of a fish farming structure 200 comprising a floatable structure 201 having a closed fish enclosure 204 suspended therefrom, the closed fish enclosure 204 comprising an upper portion 204a and a lower portion 204b. The upper portion 204a extends between the floatable structure 201 and a connection to a structural frame 280, while the lower portion 204b extends from the connection and forms a base of the fish enclosure 204.

The structural frame being connected to the closed fish enclosure 204 may assist to hold the material of the closed fish enclosure 204 in tension, thereby preventing collapse of the closed fish enclosure 204, or deformation of the fish enclosure 204 due to currents or changes in water pressure within the fish enclosure 204. As such, the structure 280 may reduce the importance of having a high relative water pressure in the closed fish enclosure 204 relative to the surrounding body of water in order to prevent unwanted deformation of the fish enclosure 204. In addition, the structural frame 280 may hold the closed fish enclosure 204 in a desired configuration, form or shape which may assist, for example, in providing a preferential water flow within the fish enclosure 204 and/or improving hygiene within the closed fish enclosure 204, as will be described in more detail in the following description.

Figures 14a-c illustrate various examples of a fish farming structure 200 comprising a closed fish enclosure 204 comprising a structural frame 280. Many features described in relation to this example are similar to those described in relation to Figures 1 to 13, and therefore alike reference numerals will be used for these features, augmented by 100.

In Figure 14a, the fish farming structure 200 is illustrated as having a floatable structure 201, which in this example comprises a collar 202. In contrast to some previously described examples, the floatable structure 201 of Figure 14a comprises only a collar and does not comprise an access structure. In addition, the collar 202 of Figure 14a is configurable to float on a waterline 205 in normal operation (e.g. in an operational draft), and may not be submerged as described in the previous and following examples. Although not illustrated, the collar 202 may comprise a railing, frame or the like on an upper surface thereof to assist an operator to walk thereon. The upper surface may be the surface that is located above the waterline, and in some examples may be a surface that is flat (e.g. horizontally oriented).

The collar 202 may be or comprise an annular shape, and may have a circular, square, rectangular, polygonal or other shape. Where the cross-section is a square, rectangular or polygonal shape, the upper surface of the collar 202 may be that which is horizontally oriented.

The closed fish enclosure 204 is suspended from the floatable structure 201 from a suspension arrangement. The suspension arrangement is not illustrated in Figure 14a, although may be similar or the same as that described previously, for example in Figures 7a and 7b.

The upper portion 204a of the closed fish enclosure 204 in the example of Figure 14a (and in Figures 14b and c) may be configurable to define a volume of a prismatic or extruded shape. For example, where the horizontal cross-section of the fish enclosure 204 is circular in shape, then the upper portion 204a of the closed fish enclosure 204 may be in the shape of a sleeve, and may define a cylindrical volume. Where the horizontal cross-section is a square or rectangle, the upper portion 204a may define a cube or rectangular prism volume. The width and length, or in the case where the upper portion 204a comprises a circular or oval shape horizontal cross-section, the (major and minor) diameter of the upper portion 204a may vary with height. For example the upper portion 204a may comprise or define a truncated cone or pyramidal fluid volume. In the case of a truncated pyramid, the base of the pyramid may be the shape of the horizontal cross-section of the upper portion 204a. The upper end of the upper portion 204a may comprise an opening for providing access to the fish enclosure 204, for example that is located at the surface, e.g. located above the waterline 205. The lower end of the upper portion 204a may comprise an opening to the lower portion 204b of the fish enclosure 204.

The lower portion 204b may define a pyramidal or conical fluid volume. Alternatively the lower portion 204b may define a semi or partial spherical fluid volume, or a cubic, rectangular prism or polyhedral volume. The lower portion 204b may comprise one opening therein, which opening may be to the upper portion 204a of the fish enclosure 204. The opening may be located at an upper end of the lower portion 204b. At a lower end of the lower portion 204b may be a closure, which may be formed by the material of the fish enclosure 204. The closure may be formed by the tip of the cone or pyramid of the lower portion 204b, by the curve of the lower portion 204b when the lower portion 204 has a semi or partial sphere shape, or by a section of material where the lower portion 204 has a cubic, polyhedral or rectangular prism shape.

The lower portion and the upper portion 204a,b may be made from the same material. In some examples, the lower portion and the upper portion 204a,b may be made from the same sheet of material. In other examples, the upper portion 204a and the lower portion 204b may be made from separate sections of material.

Connected to the closed fish enclosure 204 is a structural frame 280. The structural frame 280 may be rigid or flexible. In this example, the structural frame 280 is connected to the fish enclosure 204 at the boundary between the upper portion 204a and the lower portion 204b. The structural frame 280 may be in the form of a ring or loop of material. The structural frame 280 may be in the form of an endless ring or loop, or may have a discontinuity therein, such that the structural frame 280 comprises a C- or U-shape. The structural frame 280 may extend around the periphery of the fish enclosure 204. The structural frame 280 may extend continuously or discontinuously, for example in a plurality of discontinuous segments. The structural frame may have a shape that is the same or similar to the shape of the horizontal cross-section of the fish enclosure 204 (e.g. the upper part of the fish enclosure 204a).

The structural frame 280 may connect directly to the fish enclosure 204 as is the case in Figure 14c, or may comprise a connection arrangement that connects the structural frame 280 to the fish enclosure 204.

Where the structural frame 280 connects directly to the fish enclosure 204 such that it is in contact therewith, the frame 280 may connect to an outer surface of the fish enclosure 280, and may be held in place by ties, connection loops or the like. In some examples, the structural frame 280 may be located between the upper portion 204a and the lower portion 204b, such that the structural frame 280 separates the upper portion 204a from the lower portion 204b.

In the examples of Figures 14a and 14b, the structural frame 280 is connected to the fish enclosure 204 via a connection arrangement 282. The connection arrangement may comprise a connector or plurality of connectors such as a cable, rope, cord, tie or the like that connects the structural frame 280 to the fish enclosure 204. The connector or connectors may connect directly to the fish enclosure 204.

In some examples, the connection arrangement 282 may comprise a secondary frame that connects directly to the fish enclosure 204. The secondary frame 204 may be connected to the structural frame 280 by a connector such as a cable, rope, cord, tie or the like. The secondary frame may have the same shape as the horizontal cross-section of the fish enclosure 204. The secondary frame may be rigid, and may assist the fish enclosure 204 to maintain a desired shape.

To further assist the fish enclosure 204 to hold a desired shape, the fish enclosure 204 may comprise a reinforcement band or a plurality of bands. The reinforcement band may be a band of metal or polymer with some rigidity that is integrated into, or connected to, the material of the fish enclosure. The reinforcement band may extend circumferentially. A reinforcement band may be oriented horizontally, parallel to the waterline and/or to the collar of the floatable structure 201. A reinforcement band may extend obliquely to the waterline and/or collar.

The structural frame 280 may be suspended from the fish enclosure 204, as is illustrated in Figures 14a and b. The structural frame 280 may be suspended from the fish enclosure 208 by the connector or plurality of connectors. The structural frame 280 may be suspended from the fish enclosure 204 by the connection arrangement 282. The structural frame 280 may be suspended from the secondary frame. The structural frame 280 may be suspended below the level of the lower portion 204b of the fish enclosure 204. The structural frame 280 may be connected to the fish enclosure 204 to permit relative motion between the structural frame 280 and the fish enclosure 204, which may enhance any damping effect the structural frame 280 has on the motion of the fish enclosure 204.

The structural frame may be negatively buoyant, and therefore the weight of the structural frame 280 may assist to hold the fish enclosure 204 in tension, thereby holding its shape. In other examples, the structural frame may be neutrally or positively buoyant.

As illustrated in Figures 14b and c, the floatable structure 201 may comprise a collar 202 and an access structure 208, or a plurality of access structures 208, such that the collar 202 is completely submerged as has been described in relation to the previous Figures.

Figure 15 is a perspective illustration of a fish farming structure 200 comprising a floatable structure 201 and a fish enclosure 204, the fish enclosure 204 comprising a structural frame 280. The floatable structure 201 is similar to that described in Figure 2, and comprises a collar, a plurality of access structures 108 and a plurality of inlet conduits 254, the inlet conduits 254 being arranged on each access structure 208 in an alternating configuration, such that each access structure 208 supporting an inlet conduit 254 is adjacent two access structures 208 without an inlet conduit 254, and vice versa.

Also illustrated, the inlet conduits 254 are connected to the structural frame 280, and therefore the structural frame 280 may assist to keep the inlet conduits 254 stable in the body of water, and reduce the effects of currents on the inlet conduits 254.

Figure 16 illustrates schematically an example of a fish enclosure 204 as viewed from above. In this example, fish enclosure 204 has a rectangular cross-section. In this illustration, the circulation of water in the fish enclosure 204 is shown by arrow 284. The water in the fish enclosure may be circulated by any appropriate means, such as by a fluid pump or arrangement of fluid pumps or fluid inlets positioned inside or above the fish enclosure (see Figures 1, 2 and 15, for example), and configured to generate a flow of water in the fish enclosure 204. Having a flow of water in the closed fish enclosure 204 may provide benefits, such as permitting better oxygenation of the water, and providing a more habitable environment for any fish inside the fish enclosure. Having a closed fish enclosure 204 may improve or enable water circulation therein, as momentum within the volume of water in the fish enclosure 204 may be built without significant losses due to large volumes of water exiting the fish enclosure 204.

The example of Figure 16 illustrates an additional benefit that may be possible when inducing water circulation within a closed fish enclosure 204, an in particular in a closed fish enclosure of a polyhedral shape, or that had a polygonal horizontal cross-section which may be made possible by the inclusion of a structural frame 280. In this case, the shape of the fish enclosure 204 defines a main flow region 286a located in the centre of the fish enclosure 204, in this case centrally located around the longitudinal axis of the fish enclosure 204, and at least one peripheral flow regions 286b. The at least one peripheral flow region may be located adjacent the, or each, apex defined by the fish enclosure 204 (e.g. defined by the horizontal cross-section of the fish enclosure 204). In this case, there are four peripheral flow regions 286b located at each corner of the fish enclosure 204.

Fluid flow velocity may be lower in the peripheral regions 286b compared to the main flow region 286a, and/or may be more turbulent than in the main flow region 286a. Once the main flow region 286a is established, the peripheral flow regions 286b may form naturally at the corners or apexes of the fish enclosure 204. In some examples, at least one flow obstructer 288 may be positioned to assist in slowing the fluid flow in the peripheral regions 286b and/or to assist in producing turbulent flow in a peripheral region 286b. At least one flow obstructer 288 may be positioned in the fish enclosure 204 in order to establish a peripheral flow region 286b located at an edge of the fish enclosure 204 (e.g. not adjacent a corner or apex).

Having a peripheral region 286b as described may assist to improve hygiene standards within the fish enclosure 204 by facilitating the cleaning of the fish enclosure 204. For example, sediment material such as uneaten food, fish waste or other detritus may naturally settle in the peripheral regions 286b, thereby providing regions of the enclosure 204 that may be targeted for cleaning, and at the same time meaning that the main flow region 286 is required to be cleaned less frequently. Further, the circular motion of the water in the main flow region 286a additionally creates a centrifugal force on particles suspended in the water, thereby further encouraging particles to settle in the peripheral flow regions 286b.

Although not illustrated, a partition (e.g. made from net or sheet material) may be positioned in this fish enclosure 204, or any other fish enclosures described previously or in the following paragraphs, to form at least one sub-enclosure inside the fish enclosure.

In Figure 17 there is illustrated a fish farming structure 204, showing two examples of an inlet conduit 254 secured to both the floatable structure 201 and the fish enclosure 204. On the left side of the Figure, an inlet conduit 254 is illustrated being supported by both the structural frame 280 and the floatable structure 201, and in particular an access structure 208. As described in relation to Figure 1, the inlet conduit 254 extends vertically through the access structure 208. Here, the inlet conduit 254 extends through the structural frame 280, and therefore the structural frame 280 may comprise an aperture or opening through which the inlet conduit 254 extends. In some examples, the inlet conduit 254 may be held in tension between the floatable structure 201 and the structural frame 280, and as such compression of the material of the inlet conduit 254 may be avoided, as may kinks in the material. The fluid inlet may be located below the fish enclosure 204, at a lower end of the inlet conduit 254.

On the right side of the Figure, an inlet conduit 254 is illustrated as being attached to the floatable structure 201, e.g. directly attached. However, in this case, the inlet conduit 254 is attached to the side of the access structure 208, and does not extend through the access structure 208. The inlet conduit 254 may be held in place by a tie or loop of material on the access structure 208. Similarly, the inlet conduit 254 is attached to the side of the structural frame 280, and does not extend therethrough. In this case, the structural frame 280 comprises a sleeve 292 connected thereto, through which the inlet conduit 254 is threaded. The sleeve 292 may be connected to the structural frame 280 by any appropriate means, such as by a tie, bolt, rigid connector, weld or the like. Although not illustrated, the inlet conduit 254 may run along a top or upper surface of the connected access structure 208.

The inlet conduit 254 may have a bend stiffener 290 at the inlet end thereof. In some examples, the inlet conduit 254 may be connected to an inlet hose, which may extend deeper into the body of water. In such examples the inlet conduit 254 may act as a bend stiffener for the inlet hose.

The illustration of Figure 18 shows a fish farming structure 200 having a fluid inlet conduit 254 extending horizontally through an access structure 208, for example as illustrated previously in Figure 2. Here, the fish farming structure 200 also comprises a fluid outlet conduit 292. Although in many of the described Figures, only one fluid inlet conduit 254 and one fluid outlet conduit 292 are illustrated, it should be noted that a plurality of each or either may be present, and for example may be circumferentially disposed about the fish enclosure 204, such as in an even distribution. Both the inlet to the inlet conduit 254 and the outlet of the outlet conduit 292 are located below the waterline 205 so as to retrieve and deliver water directly to and from the surrounding body of water. The inlet conduit 254 and outlet conduit 292 (or pluralities thereof) may establish at least one flow path through the fish enclosure 204, extending from the outlet of the fluid inlet 254 to the inlet of the outlet conduit 292. As illustrated, the outlet of the fluid inlet 254 may be located higher than the inlet of the fluid outlet 292 in the fish enclosure, for example the outlet of the fluid inlet 254 may be located at the top, or in the upper half, of the fish enclosure 204, while the inlet of the fluid outlet may be located at the bottom, or in the lower half, of the fish enclosure 204, thereby extending the length of a flowpath extending therebetween.

The fluid volume located in the vertical section of the fish enclosure located between the outlet of the fluid inlet 254 and the inlet of the fluid outlet 292 may be considered to form part of a flow path between the inlet conduit 254 and outlet conduit 292. This section of the fish enclosure 204 may define a transient water volume 296a. Located below the inlet to the outlet conduit 292 may be a region of relatively low flow, which may be considered a static water volume 296b. The static water volume 296b may be located outside of the flow path within the fish enclosure 204, and may function as a sump, in that it permits sedimentation of particulate matter such as fish waste, food particles or the like in the fish enclosure 204. The transient water volume 296a may have a high exchange rate of water between the surrounding body of water and the fish enclosure 204, and therefore may comprise a higher water oxygenation level, lower waste levels, and the like, therein, which is better for fish welfare.

Here, the fluid outlet conduit 292 comprises a fluid propulsion means 294, which in this example is a fluid pump. The fluid propulsion means 294 may be selectively controllable by a user, for example a user on a nearby vessel on located on the floatable structure 201. The flow rate through the fluid outlet 292 may be controlled by a user. The flow rate through the fluid outlet 292 may be varied between zero and a maximum flow rate that may be determined by the limitations of the fluid propulsion means 294. The fluid propulsion means 294 may be used to vary the volume of water in the fish enclosure 204. As the fish enclosure 204 comprises a structural frame 280, there may be less reliance on a high water pressure inside the fish enclosure 204 to maintain its shape. Therefore, when used in combination with a structural frame 280, the fluid outlet 292 and fluid propulsion means 294 may be used to control the water level inside the fish enclosure 204, and may permit a water level 205a inside the fish enclosure 204 that is lower than the waterline 205 as illustrated, or a higher water level if required.

The outlet of the inlet conduit 254 is located below the water level 205a, and in this example, the inlet conduit 254 does not comprise a fluid propulsion means. As the water level 205a inside the fish enclosure 204 is lower than the waterline 205, the siphon principle may be used to generate a flow of water into the fish enclosure 205 through the water inlet conduit 254, thereby omitting the requirement to have a fluid propulsion means. It should be noted that the outlet of the inlet conduit 254 can be positioned proximate the water level 205a, or may extend much deeper into the fish enclosure 204, and the outlet may be located at a midsection of the depth of the fish enclosure 204, or proximate the base of the fish enclosure 204. Where the inlet conduit 254 comprises fluid propulsion means or otherwise does not rely on the syphon principle, the outlet may be located above the waterline 205a.

Although in Figure 18, the fluid inlet conduit 254 is illustrated without a fluid propulsion means, while the fluid outlet conduit 292 comprises a fluid propulsion means, the opposite may also be the case. In such a case, the inlet conduit 254 would drive a fluid flow into the fish enclosure 204, while the fluid outlet conduit 292 may be a simple conduit, optionally with a valve therein to block or restrict flow therethrough if required. In this example, the fluid pressure inside the fish enclosure 204 may be required to be higher than the external body of water in order to induce a fluid flow through the outlet conduit 292.

Located at the base of the fish enclosure 204 is a waste outlet 298. The waste outlet may permit removal of sedimentation from the fish enclosure 204. The sedimentation may be in the static water volume which may be located adjacent the waste outlet 298. A waste removal conduit 268 is connected to the waste outlet 298, which may be similar to that illustrated in Figure 13, although in this example the waste removal conduit 268 extends outside of the fish enclosure from the waste outlet 298 to the floatable structure 201, here an access structure 208 thereof. Inside the access structure 208 may be a separation chamber, also similar to that as described in relation to Figure 13. Here, the waste removal conduit comprises a fluid propulsion means in the form of a fluid pump such as a submersible pump 265, a gas lift pump, or the like. In other examples, the fluid propulsion means may be located inside a separation chamber in the access structure 208 (as described in relation to Figure 13), thereby creating a vacuum pressure within the separation chamber and establishing a fluid flow in the waste removal conduit 268.

In this example, the waste removal conduit 268 extends below the structural frame 280, and the structural frame is located below the upper portion 204a, but higher than the lowest point of the lower portion 204b of the fish enclosure 204. In some other examples, the waste removal conduit 268 may extend above the structural frame 280.

a floatable structure comprising a collar (and optionally an access structure);

the closed fish enclosure comprising a first enclosure and a second enclosure, an intermediate water volume being defined between the first closed enclosure and the second closed enclosure, and at least one of the first enclosure and the second enclosure being a closed enclosure.

In Figure 19 there is illustrated a fish farming structure 400 comprising both a first and a second closed enclosure. The first farming structure 400 comprises a floatable structure 401 and a closed fish enclosure 404, the closed fish enclosure comprising a first closed enclosure 404a and a second closed enclosure 404b, with an intermediate water volume 415a being contained and defined between the first enclosure 404a and the second enclosure 404b.

Many features described in relation to this example are similar to those described in relation to Figures 1 to 13, and Figures 14 to 18, and therefore alike reference numerals will be used for these features, augmented by 300 relative to Figures 1 to 13, and augmented by 200 relative to Figures 14 to 18.

As previously described, the fish farming structure 400 comprises a floatable structure 401 comprising a collar 402, and optionally an access structure 408, although in this example only a cross-section of the collar 402 is illustrated for reasons of clarity.

In the example of Figure 19, the fish enclosure 404 comprises a first closed enclosure 404a that is completely contained within a second enclosure 404b. As will be described in the following paragraphs, the first enclosure 404a may not be completely contained within the second enclosure 404b. In some examples, the first enclosure 404 may be partially contained within the second enclosure 404b. The first and second closed enclosures may be fully-closed enclosures.

In the example of Figure 19, the first and second enclosures 404a,b have similar shapes. Here, the second enclosure 404b is larger than the first enclosure 404a, although in some other examples the second enclosure 404b may be smaller than the first enclosure 404a.

Similar to the illustration of Figure 1, the first and second enclosures 404a,b have a dome shape, which may be semi-spherical, or partial-spherical, although other shapes of enclosure 404 may be possible, as will be described.

The water volume 415a inside the first enclosure 404a may exert a pressure on the material of the first enclosure 404a, thereby causing a tension in the material of the first enclosure 404a, which may assist the first enclosure 404a to hold its shape. Similarly, the intermediate water volume 415a may exert a pressure on the material of the second enclosure 404b, thereby causing a tension in the material of the second enclosure 404b. The intermediate water volume 415a may additionally exert a pressure on the first enclosure 404a, in a direction towards the centre of the water volume 415a that will act to deform the first enclosure 404a. Therefore, it may be desirable to ensure that the pressure in the water volume 415 at a given depth is greater than the pressure in the intermediate volume 415a at that depth. As such, the water level 405a of the water volume 415a may be configurable to be higher than that of the intermediate volume 415b, as illustrated in Figure 19, thereby ensuring that the first enclosure 404a is able to hold its shape, and the material thereof to be held in tension. Equally, the surrounding body of water will exert a pressure on the second enclosure 404b in this example, where there are two enclosures 404a,b. As such, it may be desirable to ensure that the water level 405b of the intermediate volume 415b is higher than that of the surrounding body of water, as is also illustrated in Figure 19.

The intermediate volume 415b may be circulated, for example a fluid propulsion means may be positioned in the intermediate water volume 415b to circulate the water therein. The fluid propulsion means may be positioned, for example, on the floatable structure 401 or on one or both of the enclosures 404a,b themselves. In examples wherein the first closed enclosure 404a is water permeable, there may be fluid flow between the first and second fish enclosures 404a,b which may be increased by circulating the water in the intermediate water volume 415b.

In Figure 20, the fish farming structure 400 of Figure 19 is illustrated with a third closed enclosure 404c. Although in Figures 19 and 20, two and three closed enclosures are illustrated, the first farming structure 400 may comprise a plurality of enclosures of any number, for example 4, 5 or more enclosures.

The third enclosure 404c is a partial closed enclosure. A partial closed enclosure 404c may be a closed enclosure that is connected to an adjacent fish enclosure so as to form a boundary of the water volume therein, such as is illustrated in partial enclosure 404c which connects to the adjacent second enclosure 404b to form a boundary of the intermediate water volume therein, in this case a lower boundary. The volume of the intermediate water volume of a partial enclosure 404 may be less than that of a full enclosure 404a,b. The fish farming structure may comprise one or a plurality of full closed enclosures 404a,b as illustrated in Figure 19, and optionally one or a plurality of partial closed enclosures 404c.

A partial closed enclosure may be connected to an outer surface of an adjacent enclosure 404 as illustrated in Figure 20, or to an inner surface.

A partial enclosure may be connected to the surface of an adjacent enclosure 404 by any appropriate means, and the seal may be water impermeable, for example in the case where the material of the closed enclosure 404 is also water impermeable.

The use of a partial closed enclosure may provide the closed fish enclosure 404 with additional protection. A partial closed enclosure may be positioned at an area such as at the waterline 405 where the fish enclosure 404 may be vulnerable to collisions with ice or flotsam, to oil slicks or pollution from other floating chemicals, or to sea lice. Additionally or alternatively, a partial closed enclosure may be positioned around an aperture in an enclosure 404, such as a fluid inlet or outlet, which may provide additional toughness to the fish enclosure 404.

In this example, the third closed enclosure 404c encloses an upper portion of the second enclosure 404b, while the lower portion of the second enclosure 404b is located outside of the second enclosure 404b. The third enclosure 404c in this example encloses an annular water volume between the second enclosure 404b. It should be noted that this configuration is not limited to being between a second and third enclosure, and may be between a first and second, or third and fourth enclosure, for example.

Figures 21 and 22 illustrate further examples of partial enclosures. In this example, the fish farming structure 200 comprises a first enclosure 404a, which is a full closed enclosure, and a second enclosure 404b, which is a partial closed enclosure.

In Figure 21, the partial enclosure 404b is completely submerged, and is in a location that is completely below the waterline 405 in contrast to the partial enclosure of Figure 20 which is partially submerged, and partially located above the waterline 405.

The first enclosure 404a comprises an outlet 452, which in this example is located at the base of the first enclosure 404a. The second enclosure 404b, which is a partial enclosure, is located on an outer surface of the first enclosure 404a. The second enclosure 404b is located around the periphery of the outlet 452, and therefore may assist to improve the toughness of the first enclosure 404a, which may be more susceptible to tears or damage as a result of increased exposure to particulate matter in water flowing through the outlet 452. Although illustrated as surrounding an outlet 452 on the base of the first enclosure 404a, the partial enclosure 404b may be positioned around an inlet or outlet, which may be anywhere on an adjacent enclosure (e.g. the upper or lower half, the side, etc.) and not necessarily at the base.

Figure 22 illustrates an example of a partial enclosure 404b, which in this example is also a second enclosure, and an adjacent first enclosure 404a. Both a plan and elevation view are illustrated. Here, the floatable structure 401 has a cross-section of a circular annulus, and the first enclosure 404 has a circular cross section. In this example a partial enclosure 404b is illustrated that extends from the base of the first enclosure 404a to the waterline 405. In contrast to a full enclosure, the partial enclosure 404b extends around a partial circumference of the first enclosure 404a. A partial enclosure 404b may extend partially around at least one of the height and circumference of an adjacent full enclosure.

The fish farming structure 400 of Figure 23 comprises a first enclosure 404a located inside a second enclosure 404b. Here, the fish enclosure 404 comprises a structural frame 480, similar to that as described in relation to Figures 14a and b. The structural frame is connected to the fish enclosure 404, and in this example is connected to the first fish enclosure 404a.

The second enclosure 404b is located outside of the first enclosure 404a, and also connects to the structural frame 480. Here, the second enclosure 404b connects directly to the structural frame, whereas the first enclosure 404a connects to the structural frame 480 via a connection arrangement 482. The connection arrangement 482 may be or comprise a connector, which may be a tether, a tie, a rigid connector or a flexible connector, a rod, a rope, a cord, cable or the like. It should be noted that in some examples, it may be possible to connect both the first and second enclosures 404a,b (and any further enclosures, should they be present) directly to the structural frame 480. Equally, it may be possible to connect the first, second and any further enclosures 404a,b to the structural frame 480 via a connector.

In this example, the first enclosure 404a is a closed enclosure, and may or may not be water impermeable. In contrast, the second enclosure 404b may be made from a net which may permit both the flow of water and macroscopic organisms therethrough, while the closed enclosure 404a may prevent the traverse of macroscopic organisms therethrough.

As explained previously, where the fish enclosure 404 comprises a structural frame 280, there is a reduced requirement to maintain a pressure differential between the inside and outside of each enclosure 404a, 404b in order to hold the shape of the enclosure.

Therefore, for the fish farming structure 400 of Figure 23, there is no requirement to have a higher water level in the fish enclosure 404 relative to the waterline 405, or in the first enclosure 404a relative to the second enclosure 404b.

Having a structural frame 480 in combination with the fish farming structure 400 may also permit one of the enclosures to comprise a net material, which may be a sufficiently open net so as to permit the passage of macroscopic organisms therethrough (e.g. may be an open fish enclosure, or may be a semi-closed enclosure where the net material is close enough to prevent passage of other matter such as leftover feed therethrough). Having an enclosure comprising a net material may result in pressure acting on the inside of the enclosure being the same as the pressure acting on the outside of the enclosure. Having an enclosure made from or comprising net material may permit the enclosure to be more cheaply and simply constructed and installed, while providing a degree of protection to an enclosure located internally thereof. For example, such a net enclosure may prevent or restrict direct contact between a closed fish enclosure and larger sea creatures or debris, which may damage the closed enclosure (which may be a fully-closed enclosure, or a semi-closed enclosure) if they were to come into direct contact therewith.

Also illustrated in Figure 23 is the connection of both the first enclosure 404a and the second enclosure 404b to the floatable structure 401. Both the first and second enclosures 404a,b may be suspended from the floatable structure 401. The first enclosure 404a may be suspended from the access structure 408 of the floatable structure 401 as illustrated in Figure 23, or may be suspended from the collar of the floatable structure 402. The first enclosure 404a may be suspended via a rigid or flexible connector such as a rope, bracket, connector rod, cord, cable, or the like. The first enclosure 404a may be suspended from the floatable structure 401 via a suspension arrangement 406, for example as illustrated and described in reference to Figures 7a and 7b. The first enclosure 404a may be suspended from the floatable structure 401 via suspension connection such as a bracket, loop or hook (or a plurality thereof) located on the floatable structure and, for example, optionally via a rope, cable, cord or the like attached thereto, optionally comprising a stopper therein or loop thereon for engagement with the suspension connection on the floatable structure 401.

The second enclosure 404b may be suspended from the access structure 408 or may be suspended from the collar 402, as in the example of Figure 23. The second enclosure 404b may be suspended via a rigid or flexible connector, such as a rope, bracket, connector rod, cord, cable, or the like. The second enclosure 404b may be suspended from the floatable structure 401 via a suspension arrangement 406, for example as illustrated and described in reference to Figures 7a and 7b. The second enclosure 404b may be suspended from the floatable structure 401 via suspension connection such as a bracket, loop or hook (or a plurality thereof) located on the floatable structure and, for example, optionally via a rope, cable, cord or the like attached thereto, optionally comprising a stopper therein or loop thereon for engagement with the suspension connection on the floatable structure 401.

In this and the previously described examples, the first enclosure 404a may be positioned at least a predetermined minimum distance from the second enclosure 404b. The distance between the first enclosure 404a and the second enclosure 404b may be substantially constant across the entire area of the first and second enclosures 404a, 404b. Alternatively, the distance between the first and second enclosures 404a,b may vary across the volume of the first and second enclosures. For example, the distance between the first and second enclosures may increase or decrease with depth below the waterline 405. The distance between the first and second enclosures may be greatest at the point of contact of the first and second enclosures 404a,b and the structural frame 480. The distance between the first and second enclosures 404a,b may be greatest at the base and smallest at a top edge of the fish enclosures, or vice versa.

Illustrated in Figures 24a and 24b are examples of a fish enclosure 400. The fish enclosure 400 in both examples comprises a first and second enclosure 404a,b and in both examples the second enclosure 404b is connected to the structural frame 480 via a connection arrangement 482. In the example of Figure 24a, the connection arrangement 482 additionally connects the first enclosure 404a to the structural frame 480, whereas in Figure 24b, only the second enclosure 404b is connected to the structural frame 480. In the example of Figure 24a the connection arrangement 482 may comprise a first connection point to the first enclosure 404a and a second connection point to the second enclosure 404b. The connection arrangement 482 may connect the first enclosure 404a to the structural frame through the second enclosure 404b, as well as optionally through any enclosures between the first enclosure and the structural frame 480, such as through a third, fourth, fifth, etc. enclosure.

The connection arrangement 482 may comprise connector, such as a rigid or flexible connector. The connector may be or comprise an elongate member. The connection arrangement 482 may be or comprise a connector rod, rope, cord, cable or the like. The connector arrangement 482 in this and previous examples may be held in tension between a connected enclosure 404 and the structural frame 480, thereby holding the connected enclosure 404 (e.g. the connected enclosure located between the floatable structure and the connection with the structural frame 480) in tension.

As previously explained, the water level 405a in the first enclosure 404a of Figure 24a is not required to be higher than the waterline 405, as the structural frame 480 is holding the first enclosure 404a in tension, and therefore there is a reduced, or no, requirement for the pressure inside the first enclosure 404a to be higher than that of the surrounding body of water, or intermediate water volume in order to hold the shape of the first enclosure 404a. Equally, this is true of the second enclosure 404b. In this example, the water level 405b of the second enclosure 404b (e.g. the intermediate water volume 415) is approximately equal to the waterline 405, although the water levels 405a,b may also be higher than the waterline 405.

In Figure 24b, the only the second enclosure 404b is connected to the structural frame 480. As is described, for example in relation to Figures 19 and 20, the first enclosure 404a may be supported by the water pressure therein, and therefore may not require any connection to the structural frame 480, provided that the water pressure inside the first enclosure 404a is higher than that of the surrounding water volume (in this case, the intermediate water volume 415, although may also be the surrounding body of water). As illustrated, the water level in the first enclosure 404a is higher than the water level in the second enclosure 404b, which may be a simple way to ensure that the water pressure inside the first enclosure 404a is higher than that of the second enclosure 404b. In this example, the water level 405a of the first enclosure 404a is higher than the waterline 405, although this need not necessarily be the case.

In the examples of Figures 24a and 24b, the structural frame 480 is connected to the floatable structure 401 (e.g. connected via a connector). The connection arrangement 482 may therefore comprise a first connector (or a first set of connectors) that connects the structural frame 480 to the fish enclosure 404 (e.g. one or both of the first and second enclosures 404a, 404b), and a second connector (or a second set of a plurality of connectors) that connect the structural frame 480 to the floatable structure 401. The first and/or second connector (or connectors) may be flexible or rigid, and may be a cord, cable, rod, rope or the like.

According to a further example, there is a fish farming structure for a closed fish farm, comprising:

a floatable structure;

Illustrated in Figure 25 is an example of a fish farming structure 600 having a fish enclosure 604 the fish enclosure 604 comprising a first closed enclosure 604a and a second closed enclosure 604b (e.g. a fully-closed first enclosure and second enclosure 604a, b).

Contained between the first enclosure 604a and the second enclosure 604b is an intermediate water volume 615b. The first enclosure 604a additionally comprises a fluid outlet 652, which permits water to flow from a water volume 615a in the first enclosure 604a to the intermediate water volume 615b. The second enclosure 604b comprises in this example a plurality of waste outlets 698, which permit water to exit the second enclosure, for example to an external body of water, to a vessel, to a water treatment plant, or the like.

Here, at least one of the first closed enclosure 604a and the second closed enclosure 604b may be rigid (or in cases where there are three or more closed enclosures, at least one of the enclosures, for example the innermost or outermost enclosure). Having a rigid enclosure may assist the enclosure 604 to hold its shape as water flows in the intermediate water volume 615b.

In use, water may flow from the first enclosure 604a and into the second enclosure 604b, where the water may then flow to a waste outlet where it may be removed from the fish enclosure 604. As such, the fish farming structure 600 may provide a system by which waste water may be removed from the first enclosure 604a in which fish may be located thereby improving the hygiene of the fish, and the waste water may be directed to an external or destination location, which may be variable depending on the location (e.g. depending on local legal requirements, or the like). In Figure 25, a flow path for the water flowing from the outlet 652 in the first fish enclosure 604a is illustrated by arrows. The geometry and configuration of the waste outlet may therefore comprise a circulation arrangement, where fluid flow is configured to have a desired pattern/circulation.

Although not illustrated, the first enclosure 604 may be suspended from the floatable structure 601 as previously described via a suspension arrangement. In this example, the first enclosure has a polyhedral shape, and is not connected to the illustrated structural frame 680 either directly or via a connection arrangement. As such, the water pressure inside the first enclosure 604a may assist to hold the shape of the first enclosure 604a, as has been previously described. In order to maintain the polyhedral shape of the first enclosure 604a, the material of the first enclosure 604a may be reinforced in some regions, for example edges of the polyhedral enclosure may be reinforced using a reinforcement frame, metal bar, or the like. Maintaining a higher relative water pressure in the first enclosure 604a may also assist to encourage a flow of water, and therefore establish a flowpath, through fluid outlet 652.

In this example, the fish farming structure 600 comprises a structural frame 680. The illustrated second enclosure 604b, in which the first enclosure 604a is contained, is connected to the structural frame via a connection arrangement which may assist the second enclosure 604b to hold a desired shape as previously described.

At the base of the second enclosure may be located a sump 700 as in this example. The sump 700 may form part of the waste removal arrangement and/or a mort collection arrangement. The sump 700 may assist to collect particles (e.g. fish waste, fish mort, feed particles and other detritus) that settle from the water entering the second enclosure 604b via the fluid outlet 652. In this example, the second enclosure 604b comprises a lower portion in the shape of an inverted cone or pyramid, in which the sump 700 may naturally form at the base thereof (e.g. at the apex of the inverted cone or pyramid). In other examples, and depending on the geometry of the second enclosure, more than one sump 700 may form, for example in the case where the base is in the form of two or more inverted cones or pyramids.

The fluid outlet 652 directs fluid flow towards the base of the second enclosure 604b, e.g. directly at the base of the second enclosure 604b, where the sump 700 is located. The fluid outlet 652 and the positioning thereof may be considered to be or be comprised in the circulation arrangement. Directing the fluid flow in this way may assist to slow the fluid flow after flowing though the water outlet 652, thereby assisting to encourage settlement of particles in the sump 700. It should be noted that it is not necessary for the fluid outlet 652 to direct fluid flow at the sump 700, and in other examples the fluid flow may be directed at another part of the second enclosure 604b, such as a vertical wall thereof.

Located at the base of the second enclosure 604b, or the base of the sump 700 is a waste outlet 698. The waste outlet may function to remove sediment that has collected in the sump 700. The waste outlet 698 in this example is connected to a waste removal conduit 668. The waste removal conduit 668 may form part of the waste removal arrangement and/or mort collection arrangement. Although only one waste removal conduit 668 is illustrated here, there may be a plurality thereof present. The waste removal conduit 668 may deposit waste from the fish enclosure 604 in waste holding location, such as a chamber in an access structure 608, a nearby vessel, a waste processing plant, a mort container, or the like. In this example, the waste is deposited in an external location, as illustrated by the arrow 704.

Here, the waste removal conduit 668 is located externally to the second enclosure 604b, and in this example externally to the entire fish enclosure 604, although in some examples such as those where the second enclosure 604b is not the outermost enclosure, the waste removal conduit 668 may extend partially or entirely through the fish enclosure 604.

The waste removal conduit 668 extends below and to the side of the fish enclosure 604, and may comprise a connection to the fish enclosure 604. Here, the waste removal conduit 668 comprises a connection to the structural frame 680, which may be by any appropriate connection means.

In order to facilitate removal of waste, the waste removal conduit 668 may comprise or be in fluid communication with a fluid propulsion means, such as a pump 702, e.g. a submersible pump, gas lift pump or the like.

The fish enclosure 604, for example the second fish enclosure 604, may comprise a second waste outlet 698. The second waste outlet 698 may form part of the waste removal arrangement. The second waste outlet 698 may be located higher than the previously described first waste outlet 698. The second waste outlet 698 may be located in the side (e.g. a side wall) of the fish enclosure 604. In this example, a second waste outlet 698 is located in the fish enclosure 604 at the level of the floatable structure 601. The second waste outlet 698 may be the surface of the intermediate fluid volume 615b, and therefore may be annular in shape and extend around the periphery of the top of the first enclosure 604a. The second waste outlet may be connected to, or in fluid communication with, a second waste removal conduit 668. The second waste removal conduit 668 may form part of the waste removal arrangement.

While the first waste removal conduit 668 may be positioned to receive sedimentary particulate waste from the fish enclosure 604, the second waste conduit may be positioned to receive waste fluids and non-sedimentary particulate waste from the fish enclosure, for example which may comprise water-soluble contaminants or particles with a neutral buoyancy in the surrounding water.

Having the first enclosure 604a positioned inside the second enclosure 604b, and the fluid outlet 652 positioned at the base of the first enclosure 604a, may create a flowpath illustrated by arrows 708 extending from the fluid outlet 652 and through the intermediate water volume 615 towards the surface of the intermediate water volume 615b, where the waste fluid may be removed by the second waste removal conduit. The intermediate water volume 615b and the flowpath 708 therein may therefore also form part of the waste removal arrangement. The inlet of the second waste conduit 668 may be positioned at the surface of the intermediate fluid volume 615b, or below the surface at the level of the collar 602, or below the level of the collar in a section of the flowpath 708 where fluid flow is substantially vertical. The second waste conduit 668 may deposit waste in an external location, which may be the external body of water, a chamber in the floatable structure 601, a nearby vessel or processing plant, or the like.

As described in previous examples, the fish farming structure 600 comprises an inlet conduit 654. In some examples, the inlet conduit 654 may form part of the waste removal arrangement. Although one is illustrated, a plurality may be present spaced around the circumference of the structure 600. In this example, the outlet of the inlet conduit 654 is located above the water level 605 of the fish enclosure 604, and may deposit water to the fish enclosure 604 at atmospheric pressure. Water supply from the inlet conduit 654 may be used to control flow through the fluid outlet 652. For example, a constant water supply from the inlet conduit 654 may result in a constant flow of water through fluid outlet 652, while stopping the water supply may stop or reduce the flow through fluid outlet 652. The flow rate from the inlet conduit 654 may be selectively variable through use of a pump, which is illustrated in this example although other ways to selectively control fluid supply may be possible, such as by connecting the inlet conduit 654 to a supply vessel.

In Figure 26 there is illustrated a fish farming structure 600 similar to that of Figure 25, although in this example the waste removal arrangement additionally comprises a waste skimmer.

The waste skimmer may comprise a gas diffusor 710, for example an air diffusor. In this example, the gas diffusor 710 is positioned in the intermediate water volume 615b. The gas diffusor 710 may be positioned inside one enclosure and outside of a second enclosure in the fish enclosure 604, for example here the gas diffusor 710 is positioned outside of the first enclosure 604a and inside the second enclosure 604b. The gas diffusor 710 may be positioned in or adjacent to (e.g. below) the flow path 708. The gas diffusor 710 may have an annular shape, and extend continuously through the enclosure in which it is positioned. In other examples, the gas diffusor 710 may extend discontinuously, and may comprise a plurality of diffusor devices positioned in a fish enclosure, here the second enclosure 604b.

The gas diffusor 710 functions to provide a stream of bubbles, in this example in the intermediate water volume 615b. The bubbles may attract organic and non-organic compounds, and remove these compounds from the intermediate water volume 615b and trap them in a foam which forms on the surface of the intermediate water volume 615.

Therefore, having a gas diffusor 710 may assist to collect non-sedimentary particulate matter. Further, the bubbles may cause carbon dioxide dissolved in the water to be removed, and contained within the foam. The carbon dioxide (and other gases in the bubbles) may then be released into the atmosphere at the surface. In addition, the gas diffusor 710 may assist to stimulate fluid flow in the intermediate water volume, e.g. in the style of a gas lift pump. In this example, the gas diffusor 710 is positioned below the flow path 708 such that the bubbles transit through the flow path 708, here through a portion of the flow path 708 that extends substantially vertically. As such, the gas diffusor 710 may function to remove some compounds from the fluid in the flow path 708 before the fluid exits from the fish enclosure 604, which may improve the efficiency of the waste removal process.

Although not illustrated, it may be possible to provide a partition in the intermediate water volume 615, creating a plurality of compartments in the intermediate water volume. Each compartment may comprise its own gas diffuser, and therefore each compartment may be provided with a varying stream of bubbles (e.g. more or fewer) depending on the need in that compartment.

The fish farming structure 600 comprises a gas supply 712. The gas supply 712 may comprise a conduit which provides gas (e.g. air) from a surface location such as an air storage located on the floatable structure 601 or a vessel. The conduit may extend through the water volume in which the gas diffusor 710 is positioned, and connect to the gas diffusor 710 to provide gas thereto.

The waste skimmer may comprise a surface skimmer. The surface skimmer may be connected to or mounted on the floatable structure 601. The surface skimmer may be or comprise a paddle, scoop, arm or the like which is configurable to be moved across the surface of a water volume (here, the intermediate water volume 615b) in order to remove waste that has collected on the surface of the water volume. The surface skimmer may comprise perforations therein. Where the waste skimmer comprises a gas diffusor 710, the surface skimmer may remove foam that has collected on the surface.

In this example, the second waste conduit 668 is illustrated as being located below the waterline 605, and may deposit fluid directly into the surrounding body of water.

In Figure 27, there is illustrated an example of a fish farming structure 600 that comprises a first and second enclosure 604a,b, wherein the first enclosure 604a does not comprise a single fluid outlet defined therein, but instead is water permeable. Therefore, the material of the first enclosure 604a itself may function as the fluid outlet. The second fish enclosure 604b in this example is not water permeable, and comprises a waste outlet 698, which may be connected to a waste conduit as previously described. In this example, larger particles such as fish mort and large feed particles, may not be able to pass through the material of the first enclosure 604a, and therefore may be collected inside the first enclosure. Meanwhile, fluid waste may pass into the second enclosure and may exit from the waste outlet 698.

Although not illustrated in Figures 24 to 27, at least one or all of the enclosures in the fish enclosure 604 may comprise fluid propulsion devices therein, such as submersible fluid pumps, which may encourage flow of water in the respective water volumes 615. This may encourage fluid flow from one enclosure to the next (e.g. from an internally located enclosure to an adjacent externally located enclosure).

In Figure 28 there is illustrated a fish farming structure 800. Although not illustrated, the fish farming structure 800 comprises many features in common with those previously described, such as a floatable structure (comprising a collar and which may comprise an access structure) and the fish enclosure 804 may be suspended from the floatable structure via a suspension arrangement.

In this example and as in previous examples, the fish enclosure 804 comprises a plurality of closed enclosures, here two enclosures 804a, 804b, and an intermediate water volume 815b located between the two enclosures 804a,b.

The fish farming structure 800 additionally comprises a temperature control arrangement or system. The temperature control system comprises a fluid inlet 914 and a fluid outlet 916. Here one fluid inlet 914 is illustrated, as are a plurality of fluid outlets 916, although in other examples there may be a plurality of inlets 914 and/or a single outlet 916. Here the inlet 914 is located at the base of the second enclosure, and the outlet 916 is located at the waterline 805, or may be below the waterline but at or above the level of the collar, for example. Fluid may flow from the inlet 914 through a flowpath 918 in the intermediate water volume 815 and out the outlet 916. The flowpath extends from the inlet 914 to the outlet 916, which here is from the base of the fish enclosure 604 to the waterline 805 or floatable structure. However, in other examples the position of the inlet and outlet 914, 916 may be varied and as such the flowpath 918 may be different to that shown.

The fluid outlets 916 may be located on the second enclosure 804b and may therefore permit flow of fluid to the surrounding body of water, or to an intermediate water volume located external to the second enclosure 804b. Additionally or alternatively, the fluid outlets 916 may be located on the first enclosure 804a, and therefore may permit fluid flow from the intermediate fluid volume 815 to the first enclosure 804a. The fluid outlets 916 may be configurable to be opened and closed, such that a user may select between flowing a fluid from the intermediate water volume 815 to either or both of the first enclosure 804a and the surrounding body of water.

A temperature control conduit 920 may be connected to the inlet 914 to provide a flow of fluid thereto. The temperature control conduit 920 may be connected to a fluid source on a vessel, the floatable structure, a nearby plant, or to the surrounding body of water. Where the temperature control conduit 920 is connected to a fluid source on a vessel, floatable structure, nearby plant or the like, the fluid source may be fluid that has been previously circulated out of the fish enclosure 804, and may therefore be a RAS system. The temperature control conduit 920 may optionally comprise a fluid propulsion means, such as a fluid pump e.g. a submersible fluid pump.

The temperature control system may additionally comprise a temperature control means for providing water of a desired temperature in the fish enclosure 804. For example, for providing water of a desired temperature in the intermediate fluid volume 815b, and/or in the water volume 815a of the first enclosure 804a.

The temperature control means may be or comprise a heat exchanger. For example a heat exchanger (or a plurality of heat exchangers) may be situated at the fluid inlet 914. The heat exchanger may be located in the temperature control conduit 920, or in the intermediate water volume 815. The heat exchanger may be used to modify the temperature of the water in the intermediate water volume 815 to a desired water temperature. The temperature of the water in the intermediate water volume 815 may then influence the temperature of the water in the first enclosure 804a, where fish may be located. The intermediate water volume 815 may function as a thermal barrier to the first enclosure 804a, meaning that it is less affected by changes in temperature of the surrounding body of water.

The temperature control means may be or comprise the temperature control conduit 920. The temperature control conduit may extend from the inlet 914 to a location in the surrounding body of water below the fish enclosure 800, for example a layer of water that has low or negligible annual temperature fluctuations. Being further from the surface, the water below the fish enclosure 800 may have a more stable water temperature, as it may be less affected by seasonal changes in air temperature, for example. As such, flowing water of a stable temperature into the intermediate water volume 815 may also stabilise the water temperature in the first enclosure 804a, which may then be more habitable for fish therein.

Having a temperature control system may be particularly beneficial in cases where a high degree of control over the water temperature is required. For example, where a RAS system is in place, the temperature of water in the system may tend toward the temperature of the surrounding body of water, particularly as no new water may be entering the system from a depth where the water temperature may be more desirable. A temperature control system may be used to prevent the water in the fish enclosure 804 from reaching the temperature of the surrounding body of water, which may be too cold or too warm, and instead a more desirable temperature may be selected.

Illustrated in Figures 29 to 32 is a fish farming structure protector 2010 for preventing damage in a fish farming structure, for example for protecting a fish enclosure and/or a floatable structure of a fish farming structure during operation thereof, such as a fish farming structure such as those previously described in relation to Figures 1 to 28.

The protection apparatus 2010 comprises an elongated buffer 2012 and connection means 2014 for connecting to a fish farming structure, for example those as previously described in relation to Figures 1 to 28. The connection means 2014 may be for connecting to a floatable structure 2101 of a fish farming structure, for example to the collar of a floatable structure 2101.

Having protector 2010 may provide protection both to a floatable structure as well as to a fish enclosure of a fish farming structure. For example, when a fish enclosure (e.g. a closed fish enclosure, or an open fish enclosure) is raised and lowered relative to the floatable structure, the enclosure or parts thereof (e.g. the suspension arrangement) may rub or hit against the floatable structure 2101, which can cause damage to both, especially at edges or corners of the floatable structure 2101. This may be of particular relevance in cases where the fish enclosure comprises rigid materials, such as in the previously described examples, where the structure may comprise a rigid floatable structure. Therefore, having a protector 2010 may assist to protect the fish farming structure from damage during operation, thereby prolonging the lifespan of the structure, as well as provide a deformable contact surface for a fish enclosure and associated suspension arrangement (e.g. elongate members, cables, etc. thereof) which may also be vulnerable to damage, particularly as they may be under high tension as a result of supporting a high load.

As in this example, the elongated buffer 2012 may comprise a connection member, or a plurality of connection members, which may form part of the connection means 2014. The connection member may be a lip, flap, ridge, or the like that protrudes from the elongated buffer 2012. In this example, the connection member extends longitudinally along the elongated buffer 2012 (e.g. the entire length of the elongated buffer 2012) and is in the form of a flap that extends from the elongated buffer 2012, and may be placed flat against a structure, such as a floatable structure, for connection thereto.

The connection means 2014 may be any appropriate means for connecting the elongated buffer 2012 to a structure, such as an adhesive surface, a nut-and-bolt connection, a welded connection, a tie such as a cable, wire, rope or the like, or a vulcanised connection, for example. The connection means 2014 may cooperate with a connection profile on a structure to which it is to be connected, such as an aperture therein for receipt of a bolt or screw that may form part of the connection means 2014.The elongated buffer 2012 may be hollow, as in the example of Figure 29, or comprise a hollow 2024 therein. Having a hollow elongated buffer 2012 may reduce the weight of the elongated buffer 2012, while providing additional protection to the connected structure (e.g. the floatable structure) in cases where the elongated buffer 2012 itself deforms. Rather than causing damage to the connected structure, the elongated buffer may simply deform into the hollow space therein.

The protector 2010 may be made from single piece or section of material, although a protector 2010 made from multiple sections of material may also be possible. The protector 2010 may be made from a flexible material, such as a flexible plastic. The material of the protector 2010 may be an elastic material, such as a rubber material.

The elongated buffer 2012 may be flexible. The elongated buffer 2012 may be inflatable. The elongated buffer 2012 may comprise an air pocket 2022 therein, or a plurality of air pockets 2022 therein. The air pocket 2022, or plurality of air pockets, in the elongated buffer may be inflatable with a gas such as air. The air pocket 2022, or plurality of air pockets, may be located or define a wall cavity in the protector, for example in the elongated buffer 2012 of the protector 2010, and/or in the connection means 2014. Having an inflatable elongated buffer 2012 may permit the buffer to provide a cushioning effect, by providing a cushion of air between the structure and an external object, such as a fish enclosure, cables, or the like. The elongated buffer 2012 may comprise one air pocket, or a plurality of air pockets. The plurality of air pockets may extend along the length thereof and may be circumferentially and/or longitudinally spaced from one another. The plurality of air pockets may optionally be able to be expanded and contracted by inflation (e.g. if the protector 2010 is made from a plastic and/or elastic material).

The elongated buffer 2012 of Figure 29 is illustrated as being open at an end thereof. However, it should be noted that in some examples the elongated buffer may be closed at the ends thereof, and/or at the ends of the or each hollow 2024 thereof, such that the hollow 2024 is an enclosed volume between the elongated buffer 2012 and an external structure 2101, such as the corner of an external structure 2101.

The elongated buffer 2012 may comprise a curved surface, to minimise damage on an object with which it is brought into contact, such as a fish enclosure, a cable or the like, by minimising point loads on the object, and friction between the buffer 2012 and the object. The exterior surface of the buffer 2012 may be curved for this purpose.

The protector 2010 may connect to a first and a second surface 2018, 2020 of a structure, such as a floatable structure. The first surface 2018 may be non-parallel to the second surface 2020. The first surface 2018 may be obliquely orientated relative to the second surface 2020. The first surface 2018 may be perpendicular to the second surface 2020. As such, the protector 2010 may be configured to be located at, and over, and edge or corner of a structure. The protector 2010 may therefore cover and offer protection to both the first and the second surface 2018, 2020.

Illustrated in Figure 30, a fish enclosure or a suspension arrangement of the fish enclosure 2104 may be connected to the protector 2010 itself, or may be located adjacent the protector 2010. Where the fish enclosure or suspension arrangement 2104 is connected to the protector 2010, the protector may comprise an enclosure connection means 2016, such as a rib, flange, protrusion or the like that extends therefrom. The enclosure connection means may comprise a connection profile such as an aperture, a hook, a protrusion, an adhesive surface or the like for connection of a fish enclosure thereto. In both cases in Figure 30, it is illustrated that the fish enclosure or suspension arrangement 2104 is held apart from the structure 2101 via the protector 2010.

Figures 31 and 32 illustrate a second example of a protector 2010. In this example, the protector 2010 also comprises an elongate buffer 2012 and a connection means 2014, which may be similar to those as previously described. In contrast, the protector 2010 of Figures 31 and 32 does not comprise any air pockets, although comprises a hollow 2024, or in the example of Figure 32, a plurality of hollows therein. In the example of Figures 31 and 32, the protector 2010 may be made from rubber, and therefore may be sufficiently stiff to hold its shape without the requirement of air pockets, while still comprising a degree of flexibility such that it is able to elastically deform upon contact with an external object, such as a fish enclosure, suspension arrangement, or the like. As with the previous example, the protector 2010 extends across a first surface 2018 and a second surface 2020, thereby covering the surface and offering protection thereto.

As in the previous example, the connection means 2014 may be any appropriate means for connecting the elongated buffer 2012 to a structure, such as an adhesive surface, a nut-and-bolt connection, a welded connection, a tie such as a cable, wire, rope or the like, or a vulcanised connection. The connection means 2014 may cooperate with a connection profile on a structure to which it is to be connected, such as an aperture therein for receipt of a bolt or screw that may form part of the connection means 2014.

As was also illustrated in Figure 30, a fish enclosure or a suspension arrangement of the fish enclosure 2104 may be connected to the protector 2010 of Figure 32 itself, or may be located adjacent the protector 2010. Where the fish enclosure or suspension arrangement 2104 is connected to the protector 2010, the protector may comprise an enclosure connection means 2016, such as a rib, flange, protrusion or the like that extends therefrom. The enclosure connection means may comprise a connection profile such as an aperture, a hook, a protrusion, an adhesive surface or the like for connection of a fish enclosure thereto. In both cases in Figure 30, it is illustrated that the fish enclosure or suspension arrangement 2104 is held apart from the structure 2101 via the protector 2010.

The person skilled in the art realises that the present disclosure is not limited to the preferred embodiments described above. The person skilled in the art further realises that modifications and variations are possible within the scope of the appended claims.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims.

Claims

1. A fish farming structure for a closed fish farm, comprising:

a floatable structure comprising a collar and an access structure;

and the closed fish enclosure being configurable to extend above the level of the collar.

2. The fish farming structure according to any preceding claim, wherein the fish enclosure comprises a water impermeable barrier.

3. The fish farming structure according to claim 1 or 2, wherein the closed fish enclosure comprises a fluid outlet for permitting flow of a fluid from the fish enclosure to a body of water, and a fluid inlet for permitting flow of a fluid to the fish enclosure from a body of water, wherein the fluid flow rate through the fluid inlet is selectably variable so as to permit raising and lowering of the water level of a water volume inside the closed fish enclosure.

4. The fish farming structure according to claim 3, wherein the water level of the water volume inside the closed fish enclosure is configurable to be higher than the waterline of a surrounding body of water.

5. The fish farming structure according to claim 3 or 4, wherein the water inlet comprises a fluid pump.

6. The fish farming structure according to any of claims 3 to 5, wherein the water inlet comprises an inlet conduit extending from below the fish enclosure at least to the level of the fish enclosure.

7. The fish farming structure according to claim 6, wherein the inlet conduit extends through the access structure.

8. The fish farming structure according to any preceding claim, comprising a waste removal arrangement located inside the access structure.

9. The fish farming structure according to any preceding claim, wherein the collar is circular in shape.

10. The fish farming structure according to any preceding claim, wherein the collar is polygonal in shape.

11. The fish farming structure according to any preceding claim, comprising a plurality of access structures.

12. The fish farming structure according to claim 11, comprising a support structure extending between at least two of the plurality of access structures.

13. The fish farming structure according to claim 12, wherein the fish enclosure is connected to the support structure.

14. The fish farming structure according to any preceding claim, wherein the closed fish enclosure is connected directly to the access structure.

15. The fish farming structure according to any preceding claim, comprising a plurality of access structures, and wherein the closed fish enclosure is connected directly to each of the plurality of access structures.

16. The fish farming structure according to any preceding claim, wherein the suspension arrangement comprises a first and a second elongate member that connect the floatable structure to the fish enclosure via a first and a second pulley, the first and second pulleys being located on the access structure.

17. The fish farming structure according to any preceding claim, comprising a roof enclosure.

18. The fish farming structure according to any preceding claim, wherein the roof enclosure is inflatable.

19. The fish farming structure according to any preceding claim, wherein the access structure comprises a horizontal protrusion, the suspension arrangement extending from an underside of the protrusion.

20. The fish farming structure according to any preceding claim, wherein the fish enclosure is comprised of at least one section of water impermeable material, and at least one section of water permeable material.

21. The fish farming structure according to claim 20, wherein the at least one section of water permeable material is located at an upper section of the fish enclosure and locatable above the water level in the fish enclosure, and the at least one section of water impermeable material is located at a lower section of the fish enclosure.

22. The fish farming structure according to any preceding claim, comprising a mort collection arrangement comprising a conduit extending from the fish enclosure to a mort container.