JP7675748B2 - Apparatus, Assembly and Method for Use in High Energy Marine Environments - Patent application - Google Patents

Description

The present invention relates to an apparatus and its use in aquaculture. The present invention also relates to a retainer and receiver assembly for use in the underwater positioning of buoyant devices on mooring lines. In particular, but not exclusively, the present invention relates to an aquaculture apparatus and assembly suitable for use in high energy marine environments.

Costa-Pierce (2016) in his paper on marine aquaculture (mariculture) is the only solution to the world's food supply. There is an urgent need to develop large-scale open-ocean aquaculture, as coastal urbanization, industrialization, water pollution, and overall environmental degradation limit the availability of sites for near-shore mariculture. Utilization of open-ocean sites requires the development of robust underwater technologies.

U.S. Patent No. 5,399,323 to Burgess (1997) discloses a submersible platform for cultivating crustaceans, such as mussels and oysters. The platform includes a frame incorporating an adjustable buoyancy chamber and is submersible.

Bugrov et al. (1998) in U.S. Pat. No. 5,393,633 disclose a fish cage having means for providing constant buoyancy and a vertical positioning system including negatively buoyant flexible members. The fish cage is held in place by a combination of guy lines, intermediate floats and other lines.

Jorgensen (2001) discloses a fish cage attached to a central unit. The fish cage is either fixed to the central unit or movable. The fish cage can be in any vertical position between the mooring devices on the central unit or the surface units.

Buck and Buchholz (2007) in US Pat. No. 5,399,633 disclose a device for cultivating marine organisms that includes a pair of coaxial and coplanar rings with radial and coaxial culture lines disposed between them. The device is held submerged between a float at the surface and an anchor weight on the seabed by ropes connected to the outside of the two coaxial rings.

Nos. 4,393,133 and 4,393,200 to Cortinas and Arbones (2008 and 2010) disclose systems for use as submersible mollusc farms. In one of the disclosed systems, ropes for growing mollusks are suspended from cables stretched between end floats. The buoyancy of the end floats can be adjusted to raise or lower the farm. Tension buoys are connected to the end floats through a series of cables and pulleys attached to weights. In another of the disclosed systems, a submerged frame moves vertically along a guide tube mated to a surface float.

Leslie and Young (2011) in US Pat. No. 5,399,633 disclose an aquaculture apparatus for cultivating oysters in deep water. The apparatus includes a plurality of floating bodies, each of which is fixed to the ocean floor. The position of each floating body relative to the water surface is adjustable.

U.S. Patent No. 5,399,433 to Thorvardarson et al. (2011) discloses a submersible cage for fish farming. The cage includes a buoyant structure positioned about a central axle and a net attached to the buoyant structure. The submerged cage can be rotated about the central axle. Mooring lines are shown attached to one or both ends of the central axle and to fixed or mooring points.

Menard (2015 and 2020) discloses an offshore aquaculture facility. The facility includes a ballasted buoyant structure that is submersible and anchored at one point. The facility includes one or more square or rectangular cages that are accessible via a handling bridge on top of the facility.

Newell (2016 and 2017) discloses a modular submersible aquaculture raft. The raft is submersible and the weight of the raft is distributed among multiple float devices at the water surface.

Systems for offshore farming of marine species need to be adaptable, robust, and simple to operate and maintain if they are to be economically viable. Buck and Langan (2017) provide a review of recent approaches to sustainable offshore food production and the development of technologies required in these high-energy environments.

British Patent No. 2302525 International Publication No. WO 98/06254 US Patent Application Publication No. 2007/0193115 U.S. Pat. No. 7,341,021 U.S. Pat. No. 7,650,856 International Publication No. 2011/123895 US Patent Application Publication No. 2011/0126447

Costa-Pierce (2016) Ocean foods ecosystems for planetary survival in the Anthropocene. In E.M. Binder (Ed.), World Nutrition Forum: Driving the Protein Economy (pp. 301-320). Austria: Erber, AG. Buck and Langan (2017) Aquaculture perspective of multi-use sites in the open ocean - the untapped potential for marine resources in the Anthropocene. Springer International Publishing AG.

It is an object of the present invention to provide an apparatus that is relatively simple to deploy and operate in such high energy, open ocean environments. It is a further object of the present invention to provide a method of cultivating marine species using said apparatus. It is a still further object of the present invention to provide a system for offshore cultivating one or more marine species. Each of these objects may be read in the alternative with a view to at least providing useful options in the selection of such aquaculture apparatus, methods or systems.

In a first aspect, there is provided an aquaculture apparatus for use with a single mooring line, the apparatus comprising:
Upper and lower end frames are attached around either end of the open hollow axle so that the mooring lines can pass freely through the hollow axle;
- three or more evenly spaced beams, each attached at right angles at each end to corresponding locations on the periphery of each of the upper and lower frames;
one or more culture racks releasably attached between one or more pairs of fixtures located at corresponding locations on the periphery of each of the upper and lower frames intermediate the attached beams;
- A float sleeve mounted around the axle.

The device is buoyant when immersed in seawater. The axles, end frames and beams need to be made from a material that is resistant to seawater, such as stainless steel. Manufacturing from other materials that are sufficiently rigid and strong is also envisaged, such as fibre reinforced polymer pultrusion.

The upper and lower frames may be attached around both ends of the open hollow axle via cross beams. In one option, the cross beams are integral with the end frames. In another option, the cross beams are joined to the end frames, for example by welding. Typically, the upper and lower frames are fixed against movement around both ends of the open hollow axle.

Advantageously, the lower end of the open axle is provided with a trumpet-shaped funnel to guide the single mooring line through the hollow axle and to reduce friction on the mooring line. The upper end of the open axle is typically provided with a receiver for receiving a retainer which releasably engages the mooring line. Advantageously, engagement of the mooring line by the retainer is maintained at least in part by the buoyancy of the device.

The spaced beams provide rigidity to the system. They may be attached directly or via plates joined, for example by bolting or welding, to the end frames. The spaced beams may take the form of rectangular tubes or I-beams.

The culture racks are releasably attached to the rigid cage formed by the end frames and spaced beams via attachments which may include synthetic brushes that are slippery in water. The culture racks are thereby releasably and rotatably attached to the rigid cage formed by the end frames and spaced beams. Different types of culture racks may be releasably attached to the rigid cage, allowing different marine species to be cultured on the same equipment.

Advantageously, the float sleeve includes an interlocking float attachable to the axle so that the buoyancy provided by the float sleeve can be conveniently adjusted. The interlocking float may be a disk having a channel from its periphery to its centre and complementary protrusions and recesses on its upper and lower surfaces, dimensioned to allow the float to be attached to the axle. The interlocking float may be foam filled or hollow. The interlocking float is required to be a low density rigid structure having a substantially constant displacement at depths up to 15 metres below sea level.

In a second aspect, there is provided an assembly for releasably engaging a mooring line without slippage, the assembly including a receiver and a retainer;
the receiver is a first rigid body having an upper surface, a lower surface, and a frustoconical cavity tapering from the upper surface of the first rigid body to the lower surface of the first rigid body and dimensioned to allow the mooring line to pass freely through the first rigid body;
the retainer is a second rigid body sized to substantially fill the frustoconical cavity of the receiver and made up of two or more interlocking parts;
- The interlocking parts interlock to form an open hollow sized to receive the mooring line and have a contoured inner surface that engages the mooring line in a vice-like grip to prevent slippage when the assembly is engaged with the mooring line.

In a third aspect, there is provided a method of cultivating marine species in the open ocean using the aquaculture apparatus of the first aspect, the method comprising:
a) threading a free end of a fixed mooring line through an open hollow axle of the device to provide a device with a mooring line threaded therethrough;
b) immersing the apparatus with the mooring lines threaded therethrough to a depth of at least 5 metres below the surface of the open sea to provide a submerged apparatus;
and c) releasably engaging the mooring line with the retainer to prevent the submerged device from rising above the depth.

Typically, the methods are utilized offshore in the open ocean and the marine species include bivalve mollusks, macroalgae (seaweed) and crustacean species. Bivalve mollusks that may be cultured include spat mussels and oysters.
The mooring lines are required to be able to withstand adverse conditions, i.e. maximum tensions occurring during storms. Typically the mooring lines are wire rope mooring lines. Submerging the device to a depth of at least 5 meters below the surface reduces the risk of the mooring lines breaking. Retainers are required to engage the mooring lines to prevent slippage or unintentional release of the submerged device from the required depth.

The maximum depth to which the device can be submerged depends on local conditions and the marine species being cultured. Submerging the device to a depth of 5-15 metres below the water surface is likely to be optimal for most combinations of local conditions and marine species being cultured.

In a fourth aspect, there is provided a system for offshore farming of one or more marine species, the system comprising:
- a submerged aquaculture device according to the first aspect;
- a mooring line fixed to the seabed;
The mooring lines pass through an open hollow axle of the device and a retainer releasably engaged with the mooring lines is used to prevent the device from rising above a certain depth below the water surface.

Advantageously, the retainer in releasable engagement with the mooring lines is the only means for preventing the device from rising above a certain depth below the water surface.
Preferably, the receiver for the retainer is mounted around the upper end of the open axle of the device.More preferably, the retainer and receiver assembly of the second aspect is used to prevent the device from rising above a certain depth below the water surface.

In the description and claims of this specification, the following abbreviations, acronyms, terms and expressions have the following meanings: "buoyant" means capable or prone to remain afloat or capable of rising to the top of a liquid or gas, "complementary" means having a corresponding shape or conforming, "comprising" means "including," "containing," or "characterized by," and does not exclude any additional elements, components, or steps, and "consisting essentially of" means any element that is a material limitation, "consisting of" means excluding any element, ingredient or step not specified except impurities and other incidental; "contoured" means shaped to a particular shape; "cross beam" means cross beam; "cultivate" means to maintain in conditions suitable for growth and includes collecting and maintaining in conditions suitable for growth; "immovable" means not allowing relative movement; "halves" means two equal or corresponding parts that are or can be divided so that something becomes; and "hollow" means a hole or depression in something. "interlocking" means engaging with one another by projection and recess joints, "low density" means having a density less than the density of water, "mounted" means placed or installed on a support, "mounted around" means attached so as to not obstruct passage through the opening, such as a collar mounted around an opening, "offshore" and "open ocean" mean located in a high energy environment in the ocean, for example at least one nautical mile from shore, "rigid" means that it cannot be bent or forced out of shape, and "rotationally symmetric" means that the complementary projections and recesses of two identical stackable floats are spaced apart from one another by a single joint. With respect to the location of the recess and the buoys, the floats may be stacked in two or more orientations relative to each other, and the orientation may be reached by rotating one of the two floats about their common axis; "serrated" means having a jagged edge or surface; "sliding" means the movement or process of sliding; "truncated" means shortened by cutting off an end; "tapered" means to reduce or decrease in thickness toward one end; "threaded" means (in the context of the aquaculture device described herein) having a mooring line passing through the hollow of an open axle; and "void" means a completely empty space. Any cognates of the defined terms have the corresponding meanings.

The terms "top" and "bottom" are used to distinguish features of an aquaculture device or assembly by their relative positions when the device or assembly is deployed. Terms such as "first", "second", "third", etc., when used with respect to elements, features or integers of the subject matter defined in the description of the invention and claims, or with respect to alternative embodiments of the invention, are not intended to indicate an order of preference. An order of preference is indicated by "preferably", "more preferably", etc. Any preference for an element, feature, integer or limit of one aspect of the invention is also a preference for the same element, feature, integer or limit when present in another aspect of the invention.

Non-limiting exemplary embodiments of an aquaculture device and its use in conjunction with a retainer and receiver assembly are described with reference to the figures in the accompanying drawing pages.

A perspective view from above the cage (1) of the aquaculture device showing the upper frame (2), lower frame (3), hollow axle (4), cross beams (5), beams (6) and their mounting locations (8, 9), aquaculture rack attachments (10, 11) and receiver (12). A perspective view from below the cage (1) additionally showing the trumpet horn shaped guide (13). FIG. 1 is a perspective view of a cage (1) with interlocking floats (14) attached to a hollow axle (4) to form a float sleeve. A perspective view of the upper (top) and lower (bottom) surfaces of the floating body (14) showing the channel (15) and the complementary protrusions (16) and recesses (17). A perspective view of a cylindrical culture rack (18). A perspective view of a box-shaped aquaculture rack (19). A perspective view of a cylindrical culture rack (18) wrapped with ropes (20) for the collection of spat mussels. A perspective view of a box-shaped culture rack (19) including two boxes (22) of a culture frame (21) wrapped with oyster ropes (20). A perspective view of a box-shaped culture rack (19) loaded with oyster baskets (23). FIG. 1 is a perspective view of an aquaculture device (24) comprising interlocking floats (14) mounted on a hollow axle (4) and cylindrical culture racks (18) and box culture racks (19) mounted alternately between corresponding rack attachments (10, 11). FIG. 1 is a perspective view of an aquaculture apparatus (24) with loaded or rolled culture racks (18, 19) as shown in FIGS. 6A-6C mounted between rack attachments (11, 12). Photograph of an embodiment of an aquaculture device being deployed from the deck of a barge using a sea crane, with mooring lines and empty octagonal aquaculture cages in the foreground and interlocking floats attached to a central axle. Schematic diagram of the deployment of an aquaculture device (24) using a single mooring line (25) with a threaded anchor (26), a swivel (27), a load cell (28) and a marker buoy (29). Also shown (not to scale) is a second mooring line (25) and an adjacent surveillance buoy (30) attached to the threaded anchor (26). 11 is a schematic diagram of the deployment shown in FIG. 10 with the aquaculture device (24) at the water surface. 1A, 1B and 1C are perspective, interior and side views of a first part of a preferred embodiment of a retainer including an optional cap. 1A, 1B and 1C are perspective, side and interior views of the second part of a preferred embodiment of a retainer including an optional cap. 1 is a schematic diagram of first and second parts of a preferred embodiment of a retainer that interlocks to engage a wire rope and a receiver (tapered collar) through which the wire rope passes. 1A and 1B are cross-sectional views of the first and second interlocking parts of a preferred embodiment of a retainer and receiver (tapered collar) before (A) and after (B) releasable engagement with a mooring line.

The aquaculture device includes a cage to which the culture racks are releasably and rotatably mounted. Advantageously, the device can be deployed with a minimal amount of substructure, i.e. a single anchor for the mooring line. The cage includes a hollow axle through which the single mooring line can pass. Interlocking floats are releasably attached to the axle and form an elongated float sleeve that provides buoyancy when the device is submerged and orients the device when it is at the water surface. Advantageously, the device can be brought to the water surface and the culture racks can be inspected without raising the device out of the water.

A cage (1) is shown in FIG. 1, which includes an upper end frame (2) and a lower end frame (3) mounted around the upper and lower ends, respectively, of an open hollow axle (4). The end frames (2, 3) are attached to both ends of the hollow axle (4) via cross beams (5). A plurality of evenly spaced beams (6) joined at right angles to the periphery of each of the end frames (2, 3) at corresponding locations (8, 9) midway between the apexes of the end frames (2, 3) provide rigidity to the cage. The periphery of each of the end frames (2, 3) is additionally provided with rack attachments (10, 11) located at the apexes of the end frames (2, 3). In an alternative embodiment, the beams (6) may be joined at the apexes and the rack attachments (10, 11) may be located midway between the apexes. However, the former configuration of beams (6) and attachments (10, 11) is generally preferred as it allows larger diameter racks to be accommodated.

The end frames (2, 3) and beams (6) form an open cage (1) that allows seawater to flow through the body of the aquaculture device when it is submerged. In the embodiment shown in the diagram of the accompanying drawing pages, the end frames (2, 3) are substantially hexagonal in shape. In other embodiments, end frames that are substantially triangular, square, pentagonal, heptagonal or octagonal in shape may be used. The choice depends at least in part on the size and number of culture racks to be attached. Substantially hexagonal or octagonal end frames with two, three or four cross beams are generally preferred.

The mooring lines may pass freely through the hollow axle (4) of the cage (1). The upper frame (2) includes a receiver (12), e.g. a tapered collar, dimensioned to receive a collet or other form of retainer that releasably engages the mooring lines. Possible retainer and receiver assemblies are described in the accompanying specification of International Application No. PCT/NZ2014/000008 [WO 2014/116123]. However, a particularly preferred retainer and receiver assembly is described below. To facilitate passage of the mooring lines and reduce friction, the lower frame (3) includes a trumpet horn-shaped guide (13) as shown in FIG. 2.

Several floats (14) are shown attached to the axles (4) of the cage (1) in Figure 3, and the top and bottom surfaces of these floats (14) are shown in Figure 4. Each of the floats (14) has a circumferential to central channel (15) dimensioned to allow the float to be slidably attached to the axle (4). The floats (14) have complementary protrusions (16) and recesses (17) on their top and bottom surfaces, respectively, and are rotationally symmetric with respect to the location of these complementary protrusions (16) and recesses (17). The floats (14) are thus stackable and interlocking. The protrusions (16) and recesses (17) of the floats (14) provide interlocking in a manner similar to a mortise and tenon. When the floats (14) are attached to the axle (4), each successive float (14) is rotated about the axle (4) to ensure misalignment of the channels (15) of successive floats (14), but ensure alignment of the protrusions (16) with the complementary recesses (17) of adjacent floats (14). The floats (14) can thereby be releasably held attached to the axle (4) as an elongated "float sleeve" using a single locking mechanism and the buoyancy of the aquaculture device is easily adjusted by removing or adding individual floats (14).

Examples of interchangeable culture racks (18, 19) are shown in Figures 5A and 5B. The cylindrical culture rack (18) shown in Figure 5A can be used for mussel juvenile harvesting or for growing macroalgae (seaweed). When used for mussel juvenile harvesting, a coil or rope (20) is wrapped around the cylindrical culture rack (18) as shown in Figure 6A. When used for seaweed growing, a pre-planted fabric, e.g. linen, is wrapped around the cylindrical culture rack (18). The box culture rack (19) shown in Figure 5B is also used for mussel juvenile harvesting. When used in this manner, the culture frame (21) is wrapped with the coil or rope (20) and inserted into a box (22) designed to hold the culture frame (21). The box (22) is then inserted into the box culture rack (19) as shown in Figure 6B. The box culture racks (19) can also be used to culture oysters with oyster baskets (23) stacked in the racks as shown in FIG. 6C.

The aquaculture device (24) is shown in FIG. 7. The aquaculture device (24) is shown with a float sleeve consisting of nine interlocking floats (14) attached to the axle (4). Each float (14) is sufficiently rigid to maintain substantially the same water displacement at depths up to 15 meters. The number of floats (14) attached to the axle (4) is adjusted to provide the required buoyancy for the device. Each of the aquaculture racks (18, 19) is releasably attached between the upper rack attachment (11) and the corresponding lower rack attachment (12).

In the embodiment of the aquaculture device (24) shown in Figure 7 (unloaded culture rack) and Figure 8 (loaded culture rack), the components (end frames (2, 3), axles (4) and beams (5, 6)) are typically made from stainless steel (SS316) and welded together to provide the required rigidity, strength and durability for the cage (1) of the aquaculture device (24). As a guide to the size of the embodiment of the aquaculture device (24) shown in Figures 7 and 8, the axles (4) are 1750-2250 mm long and the sides of the hexagonal upper and lower end frames (2, 3) are 1300-1600 mm long. With ten floats (14) attached to the axles (4), the float sleeves provide a total buoyancy of approximately 1400 Kg.

The equipment is intended to have a life span of 15-20 years. Galvanized or polyurethane coated mild steel are possible alternatives to the use of stainless steel (SS316), as are the use of polymers such as high density polyethylene (HDPE) with or without fiber reinforcement. Limitations of the use of alternatives to stainless steel (SS316) include the need for sufficient stiffness and strength in the joints of the equipment. These limitations are less applicable to the culture racks (18, 19), and the use of cages made from stainless steel (SS316) with racks made from alternative materials is expected due to the greater facility that culture racks (18, 19) can be inspected or replaced in the aquaculture equipment (24).

The aquaculture device (24) is typically deployed from the deck of a vessel, e.g., a barge, using a sea crane as shown in FIG. 9. The aquaculture device (24) is deployed using a single mooring line fixed offshore. For example, the mooring line (25) may be attached to a screw anchor (26) installed at a depth of about 45 meters as shown in FIG. 10. Advantageously, a swivel (27) is included in the mooring line (25) below the depth at which the aquaculture device (24) will be deployed. Installing the swivel at a depth of 16 to 20 meters is suitable for most uses of the aquaculture device. The mooring line (25) may also include a load cell (28) located below the depth at which the aquaculture device (24) will be deployed but above the position of the swivel (27). Installing the load cell at a depth of 8 to 10 meters is suitable when the aquaculture device is submerged 5 meters below the water surface. The load cells (28) may serve to provide remote monitoring of the loading of the mooring lines when the aquaculture device (24) is deployed. The swivels (27) serve to relieve tension in the mooring lines when the deployed aquaculture device (24) is rotated by currents and wave motion.

The location of the mooring lines is identified by a single surface marker buoy (29) that can be easily brought to the deck of the vessel and temporarily separated from the mooring lines. The free ends of the mooring lines are then threaded through the trumpet horn guide (13) of the aquaculture device (24) and through the hollow of the axle (4). Enough of the mooring lines are threaded through the hollow of the axle (4) to allow a collet or other form of retainer that releasably engages the mooring lines (25) to be introduced and the surface marker buoy (29) to be reattached. If a collet is used, the mooring lines (25) are fed through the collet before reattachment of the marker buoy (29). Other retainers may include a pair of tapered collars that in combination perform the same function as a collet, i.e., engage the mooring lines (25) when their outer surfaces abut the inner wall of the receiver (12).

The moored aquaculture unit (24) is attached to the hook of the sea crane, raised from the deck of the vessel, and lowered to the water surface. To facilitate submersion, the moored aquaculture unit (24) may be temporarily weighted and guided to the required depth with the assistance of scuba divers. The moored aquaculture unit (24) is typically submerged to a depth of 5-10 meters below the surface, the depth being measured from the top surface of the top frame (2) of the aquaculture unit (24). Once the collet or other form of retainer is in place, any weights temporarily attached to the moored aquaculture unit (24) may be removed and attached to the hook of the sea crane, and the moored aquaculture unit (24) is then separated from the hook.

Mooring lines (25) often need to be wire ropes. Steel wire ropes and their use as mooring lines are well known. Examples of wire ropes suitable for use in marine and offshore applications in conjunction with assemblies include those offered by Katradis (Piraeus, Greece). Wire rope mooring lines are generally less susceptible to stretching as opposed to mooring lines that are ropes made from natural fibers or synthetic materials, such as polyethylene. In use, the cross section of the mooring line is therefore more constant and resistant to compression.

With reference to Figures 12-15 of the accompanying drawing pages, a retainer and receiver assembly is described that is particularly suitable for use with a wire rope mooring line (25). The retainer includes two asymmetric interlocking halves (31, 37). While use of the assembly is described in the context of deploying an aquaculture device (24), it will be appreciated that the assembly may be advantageously used in the deployment of any buoyant marine device where releasable engagement with a mooring line (25) is required.

Referring to FIG. 12, the first half of the retainer (31) is shown. The first half of the retainer (31) has an inner surface and an outer surface. The length of the inner surface is provided with a central, elongated, open channel (32) that is sized to accommodate the mooring line (25) when the two asymmetric interlocking halves (31, 37) are assembled. The first half of the retainer (31) is also provided with two projections (33, 34) from the inner surface on either side of the channel (32). The opposing surfaces of the two projections (33, 34) are continuous with the sidewalls of the channel (32) and each have a contoured surface (35, 36).

Referring to FIG. 13, the second half of the retainer (37) is shown. The second half of the retainer (37) has an inner surface and an outer surface. The length of the inner surface is provided with a central, elongated, open channel (38) that mirrors the central, elongated, open channel of the first half of the retainer (31). The second half of the retainer (37) is also provided with two pairs of protrusions (39, 40, 41, 42) from the inner surface on either side of the channel (32) that define recesses for receiving the protrusions (33, 34) of the first half of the retainer (31). The opposing surfaces of the two pairs of protrusions (39, 40, 41, 42) are continuous with the sidewalls of the channel (38) and each has a contoured surface (43, 44, 46, 47).

The contoured surfaces (35, 36, 43, 44, 46, 47) may be complementary to the surface of a preselected mooring line, or may simply be serrated. When the contoured surfaces are complementary to the surface of a preselected mooring line, slippage avoidance is most effectively achieved with the use of four, five, or six strand wire rope mooring lines.

The facial surfaces of the first (31) and second (37) halves of the retainer are complementary, and the outer surfaces of the first (31) and second (37) halves of the retainer are curved such that when the halves (31, 37) are interlocked, the body of the retainer is formed as a truncated cone through which the mooring line (25) passes and is held in a vice-like grip when the retainer is housed within the receiver.

14 and 15, the interlocking of the first and second halves (31, 37) and the engagement of the so-formed retainer with the mooring line (25) are shown. In FIG. 14, the inner surfaces of the first and second halves (31, 37) of the retainer are shown prior to engagement of the retainer with the mooring line (25). The receiver (12) is shown as a tapered collar. However, it is recognized that the receiver (12) need only be a rigid body providing a frustoconical cavity tapering from the rigid upper surface to the rigid lower surface. The retainer is sized to substantially fill this cavity. In FIG. 15, a cross-sectional view of the interlocking first and second halves (31, 37) of the retainer is shown engaging the mooring line (25) with the retainer now fixed in place by the receiver (12). Deployment of the aquaculture device (24) shown in FIG. 10 using this retainer (31, 37) and receiver (12) assembly has been shown to be capable of withstanding water current velocities of 40 cm/s and waves up to 5 meters high.

When the aquaculture device (24) is to be inspected or harvested, the procedure for deployment can be repeated in reverse. For example, the hook of the sea crane can be attached to the aquaculture device, a weight temporarily attached to the aquaculture device through which the mooring line is threaded if necessary to facilitate disengagement with the mooring line, and the two halves (31, 37) of the retainer that has been pulled from the receiver (12), thereby allowing the aquaculture device (24) to be pulled to the surface. In some circumstances, the buoyancy provided by the float sleeve can be sufficient to raise the aquaculture device (24) to the surface when the retainer is pulled from the receiver (12) without the need to use a sea crane.

At the water surface, when unweighted, the buoyancy provided by the interlocking floats (14) of the float sleeves attached to the axles (4) orients the aquaculture device (24) with the length of the axles (4) substantially parallel to the water surface as shown in FIG. 11. Each of the culture racks (18, 19) can then be conveniently inspected by simply rotating the aquaculture device (24) about this axis. This feature and its use of the aquaculture device eliminates the need to lift the aquaculture device (24) out of the water, thereby increasing the efficiency of operations and repair management. Once deployed, the aquaculture device can be periodically inspected from the deck of a barge without the need for specially designed vessels.

Although the devices, assemblies and their uses have been described with reference to exemplary embodiments, it will be understood that changes and modifications may be made to these embodiments without departing from the scope of the present invention. Where known equivalents exist of specific elements, features or integers of the aquaculture device and their uses, such equivalents are incorporated as if specifically mentioned in this description. Unless specifically denied, variations and modifications of the described embodiments, including elements, features or integers disclosed in the referenced publications and elements, features or integers selected from the referenced publications, are within the scope of the present invention and are incorporated herein by reference. The advantages provided by the described embodiments may be provided in alternative forms or in combinations of different embodiments of the present invention.

Apparatuses, assemblies and methods for their use in the cultivation of marine species in open ocean environments are provided.
References

INCORPORATION BY REFERENCE If the claims, specification, or drawings of this application are missing, in whole or in part, the corresponding portions of the specification accompanying the most recently filed application to which priority is claimed are incorporated by reference to complete this specification in accordance with PCT Rules 4.18, 20.5, and 20.6 (in force as of July 1, 2015, or as subsequently amended).

For purposes of 37 C.F.R. 1.57, the disclosures of the following publications (more specifically identified under the heading "References") are incorporated by reference: Buck and Langan (2017) and Heasman (2014).

Claims (7)

1. A floating aquaculture device for use with a single mooring line, comprising:
(a) upper and lower frames mounted around either end of an open hollow axle such that the mooring lines can pass freely through the hollow of the axle;
(b) three or more evenly spaced beams, each mounted at right angles between corresponding locations on the periphery of each of said upper and lower frames;
(c) one or more culture racks, each releasably mounted between a pair of fixtures disposed at corresponding locations on the periphery of each of the upper and lower frames intermediate the locations at which the beams are mounted;
(d) a float sleeve attached about said axle. The apparatus of claim 1, wherein the float sleeve comprises a plurality of interlocking floats releasably mounted about the axle. The device of claim 1 or 2, wherein a guide for the mooring line is mounted around the lower end of the open axle. The apparatus of any one of claims 1 to 3, wherein a receiver for a retainer for releasably engaging the mooring line is mounted around an upper end of the open axle. 1. A method for cultivating marine species in the open ocean, comprising the steps of:
(a) passing a free end of a fixed mooring line through an open hollow axle of the device according to any one of claims 1 to 4 to provide a device through which the mooring line is passed;
(b) immersing the apparatus with the mooring lines therethrough to a depth of 5 to 15 meters below the surface of the open ocean to provide a submerged apparatus;
(c) releasably engaging the mooring line with a retainer to prevent the submerged device from rising above the depth. The method of claim 5 , wherein a receiver for said retainer is mounted about an upper end of said open axle of said device. The method of claim 6 , wherein the retainer includes an asymmetric pair of interlocking halves that engage the mooring lines in a vice-like grip.

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