NZ556110A - Spat cultivation with warp carrying looms sandwiching weed spat as a substitute carrier - Google Patents

Abstract

An enclosure is disclosed for retaining spat consisting of two warp carrying looms so as to sandwich weed carrying spat and being presented as a substitute carrier.

Description

NEW ZEALAND PATENTS ACT, 1953 No: 556110 Date: 22 June 2007 COMPLETE SPECIFICATION SPAT CULTIVATION METHOD AND APPARATUS I, CHRISTOPHER ALLEN HENSLEY, a New Zealand citizen of 4231 Far North Road, RD 4, Kaitaia 0486, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: FIELD OF THE INVENTION The present invention relates to a spat cultivation method and apparatus and related mussel cultivation.

BACKGROUND TO THE INVENTION Spat are young shellfish. In nature, mussel spat attach to seaweed. They start out roughly about the size of a pinhead around 250 p.m, but range in size up to 5 mm in shell length. Spat attached to weed, such as seaweed or macro-algae is referred to as "spat/weed". It can be found at certain periods on beaches or shore lines where this spat/weed is frequendy cast ashore. They are the raw material for mussel farms. Spat/weed is collected from beaches and is supplied to mussel farms where the spat is grown to harvest sized mussels attached to production ropes. Mussel farms are established in bodies of water where the production ropes are exposed to flowing currents. It has been found that such locations encourage the desired growth of mussels.

Mussel farms take spat/weed and utilise it in a nursery setting first. The spat/weed is held in close proximity to a nursery rope by means of a cotton or poly cotton stocking about the rope. The nursery rope allows the spat to develop into small shell fish of a size between about 20 -40mm. The small shellfish are then taken off the nursery ropes and reseeded on production ropes where the shellfish grow to a harvestable size. Mussels may take between 15 and 18 months to grow to a harvestable size of between about 90 and 120 mm. Mussel density is around about 250 mussels per metre of production rope.

Beach cast spat/weed has historically been sold to mussel farmers in 10 kg bags. For each of these 10 kg bags a mussel farmer can create on average about 200 m of spat populated nursery rope. Not all spat transfers from the weed to the nursery rope. Only a small percentage of the spat, typically much less than about 20% and often as litde as 1% transfers from the spat/weed to the nursery rope. Much of the spat/weed deteriorates or is wasted away before the majority of the spat has had a chance to transfer to the rope. Therefore, a large amount of spat/weed is unutilised.

The quota management system currendy operative in New Zealand limits the amount of spat/weed that can be harvested in any given year. Unutilised spat/weed hence is therefore a wasted resource and has a negative impact on farm production volumes and farm operating costs.

Nature's supply of spat/weed is irregular. The supply has a seasonal component, but even then irregularities exist. At times when nature supplies ample spat/weed the low spat transfer yield of spat from weed to the rope, is not an issue. Mussel farmers can merely use more spat/weed to yield the numbers or lengths of seeded spat that they desire.

But at times, spat/weed supply is below that demanded by farms. A higher yielding method of spat transfer is therefore desirable. A method of making good use of small quantities or low density spat/weed (which is currently uneconomic to harvest because of poor rates of transfer to mussel farms using existing spat transfer methods for spat/weed) is also desirable.

Likewise, if there is a spat/weed oversupply at times, a supply buffer may also facilitate long-term regular supply of spat. Currently spat/weed as a supply product to farmers may not be stored by farmers to achieve a buffer in a cost effective manner.

Furthermore, there have been periods when restrictions have been placed on the transfer of spat/weed to mussel farming locations around New Zealand due to bio-security concerns for spreading nuisance marine organisms, such as toxic phytoplankton. A method and system which effectively avoids the spread of nuisance marine organisms is desirable. The separation of clean spat from spat/weed for an effective method which overcomes these restrictions and bio-security concerns would be advantageous.

Accordingly, it is an object of the present invention, to provide a mussel spat cultivation method and apparatus which goes at least some way towards addressing the foregoing problems or which will at least provide the industry with a useful choice.

SUMMARY OF THE INVENTION In a first aspect, the present invention consists of a method of facilitating transfer of spat from a spat carrying weed acting as a natural carrier for spat onto a substitute carrier, the method comprising the steps of: (1) capturing a weed carrying spat in an enclosure that includes at least one enclosure boundary defined by a substitute carrier, the enclosure comprising two warp carrying looms, each loom carrying a number of runs of warp with a spacing defining the boundary to the passing of weed carrying spat that is held against the warp, through the loom, the looms able to be held relative each other to sandwich the weed carrying spat there between, the warp being presented to spat as the substitute carrier, and (2) placing said enclosure in a body of water for a duration allowing at least some of the spat retained by said spat carrying weed to transfer and seed onto said substitute carrier.

Preferably, the substitute carrier is a flexible filamentous material.

Preferably, the substitute carrier is a flexible elongate rope. fimny , r# MAY 2009 -3A- Preferably, the substitute carrier is in the form of a rugose material.

Preferably, the substitute carrier is selected from one or more of the following: a fabric, netting, stocking, braid, twine, rope.

Preferably, the substitute carrier is a twine or a rope. 1 5 MAY 2009 S$> Preferably, the substitute carrier is a material selected from one or more of the following: a fibre-based material, coir, sisal, cotton, linen, polyester, polypropylene.

Preferably, the spat carrying weed is harvested from a harvest location. More preferably, the harvest location is a beach.

Preferably, the spat carrying weed is beach cast spat carrying weed.

Preferably, the method further includes the step of: (3i) after said duration: (a) disposing of weed remaining in said enclosure at a location proximate the harvest location, or (b) re-utilising said weed for the purposes of extracting further spat from said weed, or (c) in part both (a) and (b).

Preferably, the disposing of weed remaining in said enclosure at a location proximate the harvest location in step 3i(a) is made into a body of water at said location.

Preferably, the re-utilising of said weed in step 3i(b) transfers remaining spat on said weed onto the substitute carrier.

Preferably, the re-utilising of said weed in step 3i(b) transfers remaining spat on said weed onto spat nursery structures at a mussel farm.

Alternatively, preferably spat carrying weed harvested from a harvest location comprises the further steps of: (3ii) after said duration (a) disposing of weed remaining in said enclosure at a location proximate the harvest location or, (b) transporting said weed to a mussel farm to allow it to be used for extracting further spat from said weed, or (c) in part both (a) and (b).

Alternatively, preferably the disposing of weed remaining in said enclosure at a location proximate the harvest location in step 3ii(a) is made into a body of water at said location. Preferably, after said duration has lapsed remaining weed is re-utilised for the transfer of remaining spat on said weed onto spat nursery structures.

Preferably, wherein disposing of said weed at step 3ii(a) occurs by opening the enclosure and allowing the weed to drop out whilst the enclosure is placed in a body of water proximate said harvest location.

Preferably, when the body of water is not proximate the harvest location the method further includes, in the numerical sequence defined above, the steps of: (2a) removing said enclosure from said body of water, (2b) removing remaining weed from said enclosure, and (2c) transporting the remaining weed so removed to a said location proximate the harvest location.

Preferably, after conducting step 2b, seeded substitute carrier is returned back to a or the body of water allowing growth of said spat to occur.

Preferably, the enclosure defines a sandwich structure of said substitute carrier intermediate of which and by which the spat carrying weed is held.

Preferably, the sandwich structure is comprised of two frames, each including a frame member or members each side of the enclosure boundary, and said substitute carrier held by said frame member(s) spanning across an area to define said enclosure boundary.

Preferably, each frame holds said substitute carrier wound onto said frame.

Preferably, the frame holds said substitute carrier in a manner such that said substitute carrier defining said enclosure boundary of one of said frames can be placed contiguous the substitute carrier defining said enclosure boundary of the other frame.

Preferably, each frame is configured to hold said substitute carrier in a manner that defines a planar enclosure boundary.

Preferably, the substitute carrier is wound in a manner so that adjacent runs of substitute carrier are spaced sufficiendy proximate each other to capture and substantially prevent any significant loss for spat carrying weed from within the enclosure.

Preferably, the wound substitute carrier on an opposing pair of frames are opposite to one another to further facilitate the retention of spat carrying weed.

Preferably, said two frames are releasably held to each other.

Preferably, the two frames are releasably held at a distance of substantially 0 to 50 mm from each other.

Preferably, wherein during the duration the frames are held together.

Preferably, the method further comprises, after step 2b: separation of the frames, recovery of remaining weed, and a return back to a or the body of water to allow growth of said spat to occur, both sides of the substitute carrier defined enclosure boundary then being exposed to the body of water to allow redistribution of seeded spat to occur on said substitute carrier.

Preferably, the returned seeded substitute carrier remains in the body of water for a further duration (storage duration) during times of supply of beach cast spat. In this circumstance, spat-laden carrier may be later utilised for transfer to production ropes at mussel farms during times when supply of beach cast spat cannot meet the demand requirements for spat.

Preferably, the returned seeded substitute carrier is utilised for subsequent transfer to production ropes at mussel farms during times when supply of beach cast spat does not meet the demand requirements for spat.

Preferably, whilst the spat seeded substitute carrier remains in said body of water, the remaining spat carrying weed is utilised for facilitation of farther spat from said weed. Optionally, this step may be carried out by repeating the transferral process or by transporting the said weed to be seeded directly onto nursery ropes at a mussel farm location.

Preferably, the remaining spat carrying weed is utilised at a mussel farm location.

Preferably, the two frames are, after loading with weed and moved into a sandwiched position, held or moored in a substantially vertical position or a substantially horizontal position submerged in a body of water.

Preferably, the body of water is the sea or a seawater enclosure.

Preferably, the duration is more than 1 day.

Preferably, the spat is green lipped mussel spat, Perna canaliculus (or Greenshell™).

In a second aspect, the present invention consists of an enclosure for retaining spat carrying weed acting as a natural carrier for spat to facilitate the transfer of spat onto a substitute carrier, the enclosure comprising two warp carrying looms, each loom carrying a number of runs of warp with a spacing to define a boundary to the passing of weed carrying spat that is held against the warp, through the loom, the looms able to be held relative each other to sandwich the weed carrying spat there between, the warp being presented to spat as the substitute carrier.

Preferably, the substitute carrier is a flexible filamentous material.

Preferably, the substitute carrier is a flexible elongate rope.

Preferably, the substitute carrier is a rugose material.

Preferably, substitute carrier is selected from one or more of the following: a fabric, netting, stocking, braid, twine, rope.

Preferably, the substitute carrier is a twine or a rope. Even more preferably, the twine is coir twine.

Preferably, the substitute carrier is a material selected from one or more of the following: a fibre-based material, coir, sisal, cotton, linen, polyester, polypropylene.

Preferably, wherein the runs extend substantially parallel to each other.

Preferably, the runs are defined by at least one length of substitute carrier.

Preferably, the spacing between runs is sufficient to allow the spat carrying weed to remain captured.

Preferably, the two looms are able to be separated to a non-sandwiching condition.

Preferably, the two looms are pivotally engagable to each other.

Preferably, the two looms are releasably held to each other.

Preferably, the two looms are releasably held at a distance of substantially 0 to 50mm apart.

Preferably, each loom is a frame member or members each side of said enclosure boundary, and said substitute carrier held by said frame member(s) spans across an area to define said enclosure boundary.

Preferably, said frame holds said substitute carrier in a manner such that said substitute carrier defining said enclosure boundary of one of said frames, can be placed contiguous the substitute carrier defining said enclosure boundary of the other frame.

Preferably, each frame is configured to hold said substitute carrier in a manner so that it defines a planar enclosure boundary.

Preferably, the substitute carrier is wound on a frame in a manner so that adjacent runs of substitute carrier are spaced sufficiently proximate each other to capture and prevent any significant loss for spat carrying weed from within the enclosure.

Preferably, the runs of the substitute carrier extending parallel to each other run at 90° to the parallel runs of the substitute carrier on an opposing frame in a pair comprising a sandwich for assisting in relation of spat carrying weed within the enclosure.

Preferably, the two frames are, after loading with spat carrying weed, able to be releasably held to each other with said weed sandwiched between.

Preferably, the weed sandwiched between the two frames is in an evenly spaced layer. More preferably, the layer is not more than about 50mm thick.

Preferably, the weed sandwiched between the two frames facilitates transfer of the spat and prevents decomposition of weed.

Preferably, wherein the spat is green lipped mussel spat, Perna canaliculus (or Greenshell™).

In a third aspect, the present invention consists in the use of spat engaged substitute carrier, as provided in accordance with the first aspect, for the populating of production ropes of a mussel farm with said spat. Populating production ropes of a mussel farm with spat is usually after further growth of spat on nursery rope.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

The present invention will now be described with reference to the accompanying drawings in which Figure 1 illustrates part of the spat cultivation hardware, being a frame about which substitute carrier, such as fine coir rope, may be wound or hitched, Figure 2 shows the frame of Figure 1 about which a substitute carrier, has been wound, Figure 3 illustrates two frames about each of which a substitute carrier has been wound wherein the frames are movable relative to each other in a pivoting manner, Figure 4 shows the two frames in a contiguous position defining a sandwich structure to restrain spat/weed in between, Figure 5 illustrates a variation to the structure of Figure 4 wherein the frame defines an enclosure to contain spat/weed, but not necessarily as one part of a hinged pair, Figure 6 is a flow chart of the process that may be used for the cultivation of spat.

With reference to Figure 1-5 and Figure 6 aspects of the present invention will now be described.

Figure 7 illustrates a moored pair of frames with wound substitute carrier and spat/weed sandwiched between.

BRIEF DESCRIPTION OF THE DRAWINGS -SI- DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The present invention utilises beach cast spat/weed. This may for example be spat/weed collected from Ninety Mile Beach in Northland in New Zealand.

Spat collected in this manner and from this region produces green lipped mussels (Perna canaliculus or Greenshell™).

In nature, free spat in a body of water (e.g. the sea) may attach itself to weed that is also in the same body of water.

Spat harvested at a beach or shore line, can be cultivated in accordance with the present invention to a point where it becomes suitable for transport to mussel farms in different parts of the country for transfer to nursery ropes of such mussel farms.

The following outlines particular details of embodiments relating to the present invention.

Transfer Material Characteristics: Coir rope was one of many substitute carrier materials that have been tested, which included netting, stocking, sisal, twine, fabrics, braid and ropes made from a variety of fibres including cotton, polypropylene and polyester. Filamentous or rough surfaces on the carrier were particularly useful for encouraging the transfer and retention of spat, whilst also limiting losses due to nuisance fish predation. Substitute carrier durability and strength were also found to be important to survive submersion in the sea without deteriorating and to not break during rough handling during winding, unwinding of substitute carrier on the frame and subsequent seeding onto mussel farm nursery ropes. Low weight and low buoyancy of the carrier was also found to be important to ease handling of substitute carrier loaded frames, reduce transport costs of spat laden carrier, and to assist in submerging and mooring the frames beneath the water. Low cost of the substitute carrier was also an important consideration. In many of these regards fine coir rope and filamentous polypropylene and polyester twine outperformed other carrier materials tested.

Substitute Carrier and Weed Arrangement: Experiments have utilised a range of different shaped frames for holding both spat/weed and substitute carrier material. For example, a range of different sized and shaped cylindrical frames were trialled but many resulted in uneven spat distribution on the substitute carrier, or promoted the decay of the weed causing mortality in the spat. Presenting spat/weed material in thicknesses greater than about 50 - 100 mm tended to result in increased decay of the weed and poor spat migration to carrier material. Smaller cylindrical frames designed to overcome this problem were inefficient in the amount of substitute carrier material they could present to the spat/weed. Paired planar frames with spat/weed sandwiched between proved to be the most effective for spat transfer to carrier and subsequent recovery of remaining spat/weed. Square frames of a range of sizes also allowed more convenient for winding the substitute carrier efficiently, and square frames of 1 m X 1 m of size were suitable for efficient handling, but different planar shapes and sizes can be used.

Apparatus Arrangement: Experiments demonstrated that holding frames in a vertical position consistendy resulted in a high level of spat migration and even distribution of spat on substitute carrier material. Mooring frames in a horizontal position was an effective method for size sorting spat, with small spat migrating to the uppermost substitute carrier material and large spat to the lower substitute carrier material. The most effective arrangement for the vertical mooring of the frames was to suspend it 2 m beneath the sea surface either by tying off to a mussel farm surface backbone rope, or by attaching 300 mm diameter plastic floats on 2 m of line at each of the two uppermost corners of the frame, and a line attached to an anchor running from the lowermost edge of the frame. Figure 7 illustrates a substantially vertical moving arrangement 9 of deployed frames 10. Deployed frames 10 are a pair of frames with wound substitute carrier and spat/weed sandwiched between. Floats 11 are used to provide buoyancy to the frames 10. Connecting or bridal ropes 12 tether the floats 11 to the frames 10. The frames are held in position by a mooring block or anchor 13 connectable to the frames via a mooring line 14.

Spat Characteristics: Experiments have demonstrated that the invention can be used for a wide range of sizes and density of spat. Small spat of 250 [xm through to large spat of 5 mm have been successfully transferred to substitute carrier using the invention, but with modification of the time interval that the spat/weed material is left in the frame. Larger spat move onto the substitute carrier faster than small spat, which may take up to 10 days to migrate. The invention has been used effectively on densities of spat from less than 1 million spat per kg of spat/weed and upward to well over 5 million spat per kg of spat/weed. Furthermore, the invention has also been used to accumulate spat on the substitute carrier by sandwiching successive batches of spat/weed bearing low natural density of spat. In so doing, commercially viable densities of spat have been accumulated on the substitute carrier material ready for transfer to mussel farm nursery ropes.

The invention may include the use of a frame 1 as shown in Figure 1. Substitute carrier material 2 may be wound about or hitched to the frame 1 to define a substitute carrier wound frame as shown in Figure 2. Substitute carrier material 2 may be wound about two opposing ends, 3, 4 of the frame so as to establish uni-directionally extending substitute carrier enclosure 5. The substitute carrier material enclosure 5 is established by ensuring that the carrier is wound sufficiently densely about the frame such that the wound substitute carrier effectively defines a wall for the frame and creates a space (generally between about 0-50 mm) within in which to place spat/weed. The substitute carrier can alternatively be wound about the frame in a regular manner at a suitable pitch starting from one of the opposing ends 6, 7, towards the opposite end 7, 6. The carrier may be tied off or cleated off at both ends.

The substitute carrier that may be used may for example be fine coir rope or filamentous polypropylene twine. Where the substitute carrier is a twine or a rope may have a diameter of between 2 mm and 8 mm. The substitute carrier is preferably fine coir rope or fine filamentous polypropylene or polyester twine. The frame may be of a size, and the pitch of the substitute carrier wound about the frame may be such as to hold sufficient substitute carrier on a frame 1 measuring lm x lm, but larger or smaller sized frames are feasible.

The frame may be a steel structure, but may be other suitable materials for a marine environment.

With reference to Figure 3, two frames la and lb are preferably provided. These frames may be engaged to each other at a hinge 8 that defines a pivot axis between the frame la and lb. The frames la and lb may be releasably fastened to each other at or by the hinge. Each of the frames may be separated from each other for the loading of substitute carrier onto each frame separately where after frames la and lb may be connected to each other. The frames are preferably hinged or at least configurable relative to each other to define a sandwich structure as shown in Figure 4. This sandwich structure holds the longitudinally extending substitute carrier of each frame substantially in a parallel manner relative to each other and in a contiguous manner relative to each other. The frames, being substantially planar, in the sandwiched configuration as shown in Figure 4 provide each plane substantially parallel with each other. A spacing of about 0 — 50 mm between frames may be provided. The retention of spat carrying weed within the sandwich is improved where the parallel runs of the substitute carrier on a single frame run at 90° to the parallel runs of the substitute carrier on the opposing frame in a pair of frames comprising the sandwich.

With reference to Figure 5, an alternative structure is shown wherein an enclosure is defined by at least two substitute carrier defining surfaces but wherein such surfaces may be spaced from each other at a distance(d). This spacing may be about 0-50mm. In Figure 5, the device shown is an enclosure that may also include substitute carrier on the minor end and side wall surfaces or such may be provided by other means.

Spat/weed that is harvested from the sea or beach is then transferred and held within the sandwich structure of Figure 4 or in the containment region of Figure 5 so as to be restrained/contained therein.

For example approximately 5 kg of spat/weed collected, may be sandwiched within a structure of Figure 4 by evenly distributing the spat/weed on an upwardly facing surface of, for example, the substitute carrier engaged frame la. The substitute carrier wound frame lb may be moved into position to define the sandwiching structure as shown in Figure 4 to sandwich the spat/weed between the two substitute carrier surfaces. The sandwich structure will assist in restraining the movement of spat/weed captured between the surfaces. The frames la and lb are fastened together in sandwiching configuration and are then transferred into a body of water and held in a vertical or horizontal position. The frames then remain in this body of water for a particular duration which is typically 4 to 10 days depending on a number of factors, especially the size of the spat and previous handling of the spat/weed. Within the body of water the spat engaged to the weed is encouraged to migrate from the weed on to the substitute carrier.

The density of wound or hitched substitute carrier is such that it can retain the spat/weed without significant loss of spat/weed through gaps between the carrier runs. The density of the substitute carrier is not so great as to prevent flow of water therethrough. It is believed that spat seeks out areas of water flow to be exposed to nutrient and oxygen supply in the water. Areas of stagnant water quickly become depleted of nutrients and oxygen and the spat will move away from these regions. It is believed that water flows through the frames and encourages spat to seed not just on portions of the substitute carrier presenting to seaward side, but also on portions that face the substitute carrier of the opposite frame. It is believed that this encourages a more even distribution of spat on the substitute carrier.

Progress of migration may be monitored so that when a sufficient number of spat have moved to the substitute carrier (generally greater than about 1800 spat per metre of substitute carrier), the frames are removed from the water, are split and remaining spat/weed is removed. This spat/weed may still contain sufficient spat to be useful for second use in frames or use by farmers for traditional method nursery practises. Hence this remaining spat/weed may advantageously be re-utilised and be moved to farms and be used at times when demand by farms requires such supply.

At times when levels of demand can be met with directly supplied beach cast spat/weed rather than remainder spat/weed, the remainder spat weed can be weighed and returned to the sea near the harvest location. For example, this may be conducted in order to claim a credit on fished quota.

Remainder spat/weed can include large amounts of spat. Regulations in force in New Zealand at the current time requires for the return of spat/weed to occur at sites close to where the spat/weed was originally harvested. Weed carrying spat that is returned may then result in these resources re-establishing in the wild and encouraging sustainability of supply. This also has an impact on reducing the consumption of quota. A return to the sea will effectively result in a credit under the quota system provided appropriate records are kept of transfers of spat/weed material.

Once the remainder spat/weed has been removed from the sandwich structure, individual frames may then be placed in the water to allow the mussel spat to stabilise or more evenly disperse over the substitute carrier. With both sides of each frame then exposed to flowing water more even distribution is encouraged.

The substitute carrier is a medium to carry the spat in much the same way that the seaweed had previously. Preferably the substitute carrier is fine coir rope or filamentous polypropylene or polyester twine.

Once mussel spat has sufficiendy stabilised the substitute carrier may be removed from the frame.

The substitute carrier with mussel spat attached may then be sold and shipped for reseeding at a mussel farm.

Time between any remainder spat/weed being sold and shipped to farms or returned to the sea, and substitute carrier seeded spat being made available for reseeding at farms, may typically vary between 4 days and 10 days. Experimentation has demonstrated that the timing of this varies with the size of the spat and the prior handling of spat. For example, smaller spat take longer to move to the substitute carrier, as do spat that have undergone greater handling or chilling prior to undertaking the present invention. So, at times when no beach cast spat/weed is available, and any remainder spat/weed that has been supplied to farms has been consumed at farms, the substitute carrier seeded spat can then be made available to farms.

It has been found with the present process, that, 5 kg of spat/weed captured between the frames, will effectively seed a minimum of about 400 m of carrier with spat densities as low as about 1800 to 3000 spat per metre of substitute carrier. On the contrary, other traditional methods require about 10 kg of spat/weed to populate on average about 200 m of nursery rope.

The substitute carrier seeded with mussel spat may be attached to nursery ropes at a mussel farm and should seed an equivalent number of metres of a nursery rope as per the substitute carrier supplied.

The frames may each be 1 m high by 1 m each and can carry approximately 200 m of carrier providing a total of about 400 m of carrier per sandwich structure. Commercial scale tests have shown that of 288 kg of spat/weed harvested, 215 kg was returned to the sea after the seeding process. Accordingly approximately 73 kg of spat/weed was consumed and thus allowing 73% of the fished quota to be recovered through the return of the remaining spat/weed to the harvest location. This has allowed for approximately 25000 m of substitute carrier to be populated by mussel spat at average measured densities of 2790 spat per metre of substitute carrier on the inside of the frame, and 4836 on the outside, with the spat being supplied and successfully grown at 3 different mussel farms in 3 different locations. This equates to 1 kg of spat/weed seeding 340 m of nursery rope.

Of particular importance, the invention can make excellent use of small quantities of spat that were previously not commercially viable to land, but can be valuable for supplying spat to mussel farms when natural spat/weed arrival on the coast has been poor. For example, the invention has been used to make good use of 50 kg of spat/weed, of which 42 kg was subsequently returned to the harvest location (i.e. 84% quota recovery). The balance 8 kg of spat was used to seed 4000 m of substitute carrier with successful transfer to mussel farms for nursery rope culture. This equates to 1 kg of weed successfully seeding 500 m of substitute carrier.

Existing industry standard processes typically use 1 kg of spat/weed to seed approximately 20 metres of nursery rope, whereas this invention has been demonstrated to seed between 340 and 500 m of substitute carrier (direcdy equivalent to length of seeded farm nursery rope) per 1 kg of spat/weed which makes it 17 to 25 times more productive than existing spat transfer methods. Using the present process and apparatus has the potential to thus increase farmers' retention of mussel spat on their nursery ropes. It can reduce pressure on the wild fishery, alleviate problems surrounding temporal distribution and provide a cost effective way of storing spat and spat/weed in the short term (until farmers are able to handle it for the purposes of populating their nursery ropes).

The foregoing description of the invention includes preferred forms thereof. Modifications may be made thereto without departing from the scope of the invention as defined by the accompanying claims.

Claims (67)

1. A method of facilitating transfer of spat from a spat carrying weed acting as a natural carrier for spat onto a substitute carrier, the method comprising the steps of: (1) capturing a weed carrying spat in an enclosure that includes at least one enclosure boundary defined by a substitute carrier, the enclosure comprising two warp carrying looms, each loom carrying a number of runs of warp with a spacing defining the boundary to the passing of weed carrying spat that is held against the warp, through the loom, the looms able to be held relative each other to sandwich the weed carrying spat there between, the warp being presented to spat as the substitute carrier, and (2) placing said enclosure in a body of water for a duration allowing at least some of the spat retained by said spat carrying weed to transfer and seed onto said substitute carrier.

2. The method as claimed in claim 1, wherein the substitute carrier is a flexible filamentous material.

3. The method as claimed in claim 1 or claim 2, wherein the substitute carrier is a flexible elongate rope.

4. The method as claimed in any one of claims 1 to 3, wherein the substitute carrier is in the form of a rugose material.

5. The method as claimed in any one of claims 1 to 4, wherein the substitute carrier is selected from one or more of the following: a fabric, netting, stocking, braid, twine, rope.

6. The method as claimed in any one of claims 1 to 4, wherein the substitute carrier is a twine or a rope.

7. The method as claimed in any one of claims 1 to 6, wherein the substitute carrier is a material selected from one or more of the following: a fibre-based material, coir, sisal, cotton, linen, polyester, polypropylene.

8. The method as claimed in any one of claims 1 to 6, wherein spat carrying weed is harvested from a harvest location.

9. The method as claimed in claim 8, wherein the harvest location is a beach.

10. The method as claimed in any preceding claim, wherein t^^lff^ny^^^ed is beach cast spat carrying weed. -16-

11. The method as claimed in any preceding claim, further including the step of: (3i) after said duration: (a) disposing of weed remaining in said enclosure at a location proximate the harvest location, or (b) re-utilising said weed for the purposes of extracting further spat from said weed, or (c) in part both (a) and (b).

12. The method as claimed in claim 11, wherein the disposing of weed remaining in said enclosure at a location proximate the harvest location in step 3i(a) is made into a body of water at said location.

13. The method as claimed in claim 11 or claim 12, wherein the re-utilising of said weed in step 3i(b) transfers remaining spat on said weed onto the substitute carrier.

14. The method as claimed in claim 11 or claim 12, wherein re-utilising of said weed in step 3i(b) transfers remaining spat on said weed onto spat nursery structures at a mussel farm.

15. The method as claimed in any one of claims 8 to 10, wherein spat carrying weed harvested from a harvest location comprises the further steps of: (3ii) after said duration (a) disposing of weed remaining in said enclosure at a location proximate the harvest location or, (b) transporting said weed to a mussel farm to allow it to be used for extracting further spat from said weed, or (c) in part both (a) and (b).

16. The method as claimed in claim 15, wherein the disposing of weed remaining in said enclosure at a location proximate the harvest location in step 3ii(a) is made into a body of water at said location.

17. The method as claimed in any of one of claims 11 to 16, wherein after said duration has lapsed remaining weed is re-utilised for the transfer of remaining spat on said weed onto spat nursery structures. -17-

18. The method as claimed in any one of claims 11 to 17, wherein disposing of said weed at step 3ii(a) occurs by opening the enclosure and allowing the weed to drop out whilst the enclosure is placed in a body of water proximate said harvest location.

19. The method as claimed in any one of claims 11 to 18, wherein when the body of water is not proximate the harvest location the method further includes, in the numerical sequence defined above, the steps of: (2a) removing said enclosure from said body of water, (2b) removing remaining weed from said enclosure, and (2c) transporting the remaining weed so removed to a said location proximate the harvest location.

20. The method as claimed in claim 19, wherein after conducting step 2b, seeded substitute carrier is returned back to a or the body of water allowing growth of said spat to occur.

21. The method as claimed in any one of claims 1 to 20, wherein the enclosure defines a sandwich structure of said substitute carrier intermediate of which and by which the spat carrying weed is held.

22. The method as claimed in claim 21, wherein the sandwich structure is comprised of two frames, each including a frame member or members each side of the enclosure boundary, and said substitute carrier held by said frame member(s) spanning across an area to define said enclosure boundary.

23. The method as claimed in claim 22, wherein each frame holds said substitute carrier wound onto said frame.

24. The method as claimed in claim 22 or claim 23, wherein said frame holds said substitute carrier in a manner such that said substitute carrier defining said enclosure boundary of one of said frames can be placed contiguous the substitute carrier defining said enclosure boundary of the other frame.

25. The method as claimed in any one of claims 22 to 24, wherein each frame is configured to hold said substitute carrier in a manner that defines a planar enclosure boundary. -18-

26. The method as claimed in any one of claims 23 to 25, wherein the substitute carrier is wound in a manner so that adjacent runs of substitute carrier are spaced sufficiently proximate each other to capture and substantially prevent any significant loss for spat carrying weed from within the enclosure.

27. The method as claimed in any one of claims 23 to 26, wherein the wound substitute carrier on an opposing pair of frames are opposite to one another to further facilitate the retention of spat carrying weed.

28. The method as claimed in any one of claims 22 to 27, wherein said two frames are releasably held to each other.

29. The method as claimed in any one of claims 22 to 28, wherein the two frames are releasably held at a distance of substantially 0 to 50 mm from each other.

30. The method as claimed in any one of claims 22 to 29, wherein during the duration the frames are held together.

31. The method as claimed in any one of claims 22 to 30, wherein the method further comprises, after step 2b: separation of the frames, recovery of remaining weed, and a return back to a or the body of water to allow growth of said spat to occur, both sides of the substitute carrier defined enclosure boundary then being exposed to the body of water to allow redistribution of seeded spat to occur on said substitute carrier.

32. The method as claimed in claim 31, wherein the returned seeded substitute carrier remains in the body of water for a further duration (storage duration) during times of supply of beach cast spat.

33. The method as claimed in claim 32, wherein the returned seeded substitute carrier is utilised for subsequent transfer to production ropes at mussel farms during times when supply of beach cast spat does not meet the demand requirements for spat. -19 -

34. The method as claimed in 32, wherein whilst the spat seeded substitute carrier remains in said body of water, the remaining spat carrying weed is utilised for facilitation of farther spat from said weed.

35. The method as claimed in claim 34, wherein the remaining spat carrying weed is utilised at a mussel farm location.

36. The method as claimed in any one of claims 22 to 35, wherein the two frames are, after loading with weed and moved into a sandwiched position, held or moored in a substantially vertical position or a substantially horizontal position submerged in a body of water.

37. The method as claimed in any one of claims 1 to 36, wherein the body of water is the sea or a seawater enclosure.

38. The method as claimed in any one of claims 1 to 37, wherein the duration is more than 1 day.

39. The method as claimed in any one of claims 1 to 38, wherein the spat is green lipped mussels, Perna canaliculus.

40. An enclosure for retaining spat carrying weed acting as a natural carrier for spat to facilitate the transfer of spat onto a substitute carrier, the enclosure comprising two warp carrying looms, each loom carrying a number of runs of warp with a spacing to define a boundary to the passing of weed carrying spat that is held against the warp, through the loom, the looms able to be held relative each other to sandwich the weed carrying spat there between, the warp being presented to spat as the substitute carrier.

41. The enclosure as claimed in claim 40, wherein the substitute carrier is a flexible filamentous material.

42. The enclosure as claimed in claims 40 or claim 41, wherein the substitute carrier is a flexible elongate rope.

43. The enclosure as claimed in any one of claims 37 to 42, wherein the substitute carrier is a rugose material. -20-

44. The enclosure as claimed in any one of claims 40 to 43, wherein the substitute carrier is selected from one or more of the following: a fabric, netting, stocking, braid, twine, rope.

45. The enclosure as claimed in any one of claims 40 to 44, wherein the substitute carrier is a twine or a rope.

46. The enclosure as claimed in claim 45, wherein the twine is coir twine.

47. The enclosure as claimed in any one of claims 40 to 46, wherein the substitute carrier is a material selected from one or more of the following: a fibre-based material, coir, sisal, cotton, linen, polyester, polypropylene.

48. The enclosure as claimed in any one of claims 40 to 47, wherein the runs extend substantially parallel to each other.

49. The enclosure as claimed in any one of claims 40 to 48, wherein the runs are defined by at least one length of substitute carrier.

50. The enclosure as claimed in any one of claims 40 to 49, wherein spacing between runs is sufficient to allow the spat carrying weed to remain captured.

51. The enclosure as claimed in any one of claims 40 to 50, wherein the two looms are able to be separated to a non-sandwiching condition.

52. The enclosure as claimed in any one of claims 40 to 51, wherein the two looms are pivotally engagable to each other.

53. The enclosure as claimed in any one of claims 40 to 52, wherein the two looms are releasably held to each other.

54. The enclosure as claimed in any one of claims 40 to 53, wherein the two looms are releasably held at a distance of substantially 0 to 50mm apart. -21 -

55. The enclosure as claimed in any one of claims 40 to 54, wherein each loom is a frame member or members positioned each side of said enclosure boundary, and said substitute carrier held by said frame member(s) spans across an area to define said enclosure boundary.

56. The enclosure as claimed in claim 55, wherein said frame holds said substitute carrier in a manner such that said substitute carrier defining said enclosure boundary of one of said frames, can be placed contiguous the substitute carrier defining said enclosure boundary of the other frame.

57. The enclosure as claimed in claim 55 or claim 56, wherein each frame is configured to hold said substitute carrier in a manner so that it defines a planar enclosure boundary.

58. The enclosure as claimed in any one of claims 55 to 57, wherein the substitute carrier is wound on a frame in a manner so that adjacent runs of substitute carrier are spaced sufficiently proximate each other to capture and prevent any significant loss for spat carrying weed from within the enclosure.

59. The enclosure as claimed in any one of claims 55 to 58, wherein the runs of the substitute carrier extending parallel to each other run at 90° to the parallel runs of the substitute carrier on an opposing frame in a pair comprising a sandwich for assisting in relation of spat carrying weed within the enclosure.

60. The enclosure as claimed in any one of claims 55 to 59, wherein the two frames are, after loading with spat carrying weed, able to be releasably held to each other with said weed sandwiched between.

61. The enclosure as claimed in claim 60, wherein the weed sandwiched between the two frames is in an evenly spaced layer.

62. The enclosure as claimed in claim 61, wherein the layer is not more than about 50mm thick.

63. The enclosure as claimed in claim 61 or claim 62, wherein the weed sandwiched between the two frames facilitates transfer of the spat and prev 1 ' r sveed. -22-

64. The enclosure as claimed in any one of claims 40 to 63, wherein the spat is green lipped mussels, Perna canaliculus.

65. The use of spat engaged substitute carrier provided in accordance with any one of claims 1 to 39, for the populating of production ropes of a mussel farm with said spat.

66. A method substantially as hereinbefore described and as illustrated with reference to any one of the accompanying drawings.

67. An enclosure substantially as hereinbefore described and as illustrated with reference to any one of the accompanying drawings.