AU2006252094A1 - Abalone farming arrangement - Google Patents

Description

O Regulation 3.2

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AUSTRALIA

0 PATENTS ACT 1990 COMPLETE SPECIFICATION 00 FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: Eyre Peninsula Aquaculture Pty Ltd Actual Inventor: Darren Tressider Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention title: ABALONE FARMING ARRANGEMENT Details of Associated Provisional Application No: 2005907081 dated 16 December 2005 The following statement is a full description of this invention, including the best method of performing it known to us.

PatAU131 SFIELD OF THE INVENTION The present invention relates to an aquaculture farming arrangement and in O particular to an apparatus for the containment and cultivation of marine molluscs, in particular abalone and other suitable underwater species of the 00 genus Haliotis.

BACKGROUND OF THE INVENTION Abalones are large edible marine molluscs of the genus Haliotis having an earshaped shell with pearly interior. Abalone has become a high value product, grown in Australia specifically for export markets in Asia, but can be grown in C the seas about many other countries. Two species are commonly harvested those being: Haliotis rubra (blacklip abalone) and Haliotis laevigata (green lip abalone).

Abalones are mobile bottom dwellers and graze on drift seaweeds and algae on rock surfaces. Abalones prefer rocky bottoms, which they can crawl over or reside under in the darker areas.

In response to the increased global demand for abalone, numerous businesses have made attempts to farm abalone since natural sources are being depleted.

Land based aquaculture methods are the most popular methods used to farm abalone, however there are a limited number of ocean-based (or sea-based) aquaculture farming methods that have been attempted.

Land based methods suffer from a number of disadvantages, most notably the high capital and operational costs involved in pumping sea water onto land. An additional disadvantage to the high capital costs is the risk that the tubes might fail due to leakage or corrosion, or there is a power outage, causing the abalone to perish since they cannot live for more than a couple of hours in stagnant water. Land based methods also require a great deal of space in order to set up an efficient farming operation and suitable locations are restricted to those with suitable site facilities. It is preferred that the sites have access to 3-phase power, gently sloping land and suitable water temperature, etc. A further problem is IDthat land-based farming methods rely on feeding manufactured pellets to the Sabalone. The current arrangements therefore require input of labour to feed and O clean the abalone containers.

00 Ocean-based aquaculture arrangements have been proposed which provide a platform and netting arrangement, which are disposed under the surface of the water and supported by a buoyant body floating on the surface of the water.

Figure 1 depicts an already proposed abalone farming arrangement 10 floating in the ocean 20 or other body of water. The arrangement 10 is supported by buoyant body 13 which may be provided by a circular air inflated tube or pipe ci and a side wall 12 (being a mesh (not shown)) which depends into the ocean from the circular inflated tube. The sidewall 12 is arranged to support a base or platform 11.

This arrangement suffers from the disadvantage that in collecting the current crop of abalone, divers are required to dive to the top surface of the submerged platform 11 to collect the abalone. This increases the collection time and accordingly costs.

A yet further disadvantage is the inability of current arrangements to greatly change the growing conditions for algae. Ultra-violet penetration to the depth of the growing algae and abalone can vary according to the clarity of the water and time of year hence it would be advantageous to have some control over that element of the ocean based abalone grow-out platforms.

A further disadvantage with such arrangements is that of transporting the device to and from the required location. Traditionally, vessels with crane-like arrangements are required to lift the device from the water and transport it elsewhere. This is generally undesirable as not all abalone farmers have vessels equipped with cranes or lifting apparatus.

IDAnother option is to tow the device behind the vessel, but this can be difficult due to the resistance of the device in the water. This drag can significantly O increase the power requirements of the vessel as well as increase the costs to Sfuel the vessel.

00oO As demand for abalone has increased, the cost-effectiveness of existing abalone farming apparatus and methods has deteriorated. Accordingly there is a need c' for an abalone farming arrangement that produces yields of abalone at reduced c costs.

It is an object of the present invention to provide an abalone farming arrangement that addresses at least one of the above problems of the prior art.

SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided an arrangement for the cultivation of marine molluscs in a body of water, the arrangement including: a platform for supporting the molluscs in use a buoyant body, which in use floats on the surface of the body of water, for supporting the platform below the buoyant body; wherein the platform is able to be moved towards or away from the buoyant body.

Preferably, the arrangement further comprises means for moving the platform towards or away from the buoyant body.

Preferably, the means for moving the platform is located at or above the surface of the body of water to allow convenient access.

0 Preferably, the means for moving the platform is disposed on the arrangement itself.

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O Preferably, the buoyant body defines a ring commensurate with the perimetre O of the platform.

00 oO Optionally, a wall is disposed between the buoyant body and the platform.

Optionally, the wall is made from netting disposed between the platform and c' the buoyant body.

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Optionally, the netting collapses upon moving the platform towards the buoyant body.

The present invention accordingly provides a means of facilitating the collection of molluscs from the platform by enabling the platform to be raised to the surface of the water, thereby eliminating the need for divers to dive down to time restricted depths to the platform to collect the molluscs.

The present invention accordingly provides a means for setting the depth of the platform below the buoyant body to facilitate the growth of the algae on the platform.

The present invention also accordingly provides a method of cultivating algae for the feeding of marine molluscs in a body of water using a platform for supporting the molluscs that is adjustably supported below a buoyant body floating on the surface of the body of water including the step of adjusting the depth of the platform in the body of water to adjust for the effect of ultra-violet radiation on the growth of algae.

A detailed description of one or more preferred embodiments of the invention is provided below along with accompanying figures that illustrate by way of example the principles of the invention. While the invention is described in IDconnection with such embodiments, it should be understood that the invention Sis not limited to any one embodiment. On the contrary, the scope of the O invention is limited only by the appended claims and the invention encompasses numerous alternatives, modifications and equivalents. For the 00 purpose of example, numerous specific details are set forth in the following description in order to provide a thorough understanding of the present invention. The present invention may be practiced according to the claims C-i without some or all of these specific details. For the purpose of clarity, technical C material that is known in the technical fields related to the invention has not

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been described in detail so that the present invention is not unnecessarily obscured.

Throughout this specification and the claims that follow unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge.

BRIEF DESCRWITION OF THE DRAWINGS An illustrative embodiment of the present invention will be discussed with reference to the accompanying drawings and examples wherein: Figure 1 shows a perspective view of a previously proposed abalone grow-out arrangement; Figure 2 shows a perspective view of an arrangement for the cultivation of marine molluscs submerged in a body of water;

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0 Figure 3 shows a partial perspective view of the arrangement of Figure 2 O showing a portion of an outer wall and two inner abalone grow-out compartments located over a bottom platform; and 00 Figure 4a shows a side view of the arrangement of Figures 2 and 3 depicting the bottom platform at its deepest level with the raising and lowering means Ci' including a rope tied between the buoyant means and the head rope 136 of the C-i arrangement;

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c' Figure 4b shows a side view of the arrangement of Figure 4a depicting the bottom platform in a partially raised position with respect to the arrangement depicted in Figure 4a; Figure 5a shows a side view of the arrangement of Figures 2 and 3 depicting the bottom platform at its deepest level with the raising and lowering means including a rope tied between the buoyant means and the base rope 138 of the arrangement; Figure 5b shows a side view of the arrangement of Figure 5a depicting the bottom platform in a partially raised position with respect to the arrangement depicted in Figure 5a; and Figure 5c shows a side view of the arrangement of Figure 5a depicting the bottom platform in an almost fully raised position with respect to the arrangement depicted in Figure DESCRIPTION OF PREFERRED EMBODIMENT The arrangement for the cultivation of marine molluscs described is most suitable for the cultivation of abalone but the embodiment is merely an example and its use is not limited to abalone.

Wild abalone, such as green lip abalone, spawns in the Southern hemisphere between August and November. Adult abalones are induced to spawn primarily by using temperature shock technique or other means as necessary.

Spawning is conducted in a hatchery and the larvae allowed to develop in an environment conditioned to mimic the natural environment An ongoing supply of abalone is produced by this spawning and hatchery technique.

The juvenile abalones are maintained in an artificial nursery for 6 months and are fed on a micro algae diet. After 6 months the immature abalone are graded for size and those which have reached a size of 17mm across the widest part of the shell, are transferred to a grow-out arrangement to simulate an ocean growing environment. Essentially the culturing of abalone in this embodiment consists of three stages, hatchery, nursery and grow-out. The grow-out period is performed in a grow-out arrangement located in the ocean. The offshore location of the grow-out arrangement in the ocean is selected so as to optimise abalone development. A good site is characterised by: 0 good and consistent water or tidal flow; having sufficient water depth to provide algae growth that in turn supports the growing algae; being in relatively sheltered offshore waters; having a water temperature which is suitable to the grow-out of abalone; being remote from urban development; being clean and free from pollutants, or the risk of pollutants.

Allowing the grow out period for the abalone to occur in the natural environment of the ocean has the benefit of reducing stress to the animal by minimising handling during the all important grow-out period. The abalone is exposed to normal sea conditions yet are protected from predators by the growout arrangement and the routine dive maintenance crews thereby maximising IDabalone yield. Harvesting occurs when the abalone has matured and the C)abalone has a shell size of between 70-100mm or at approximately 3-4 years of O age, dependant upon market demands.

00 While the abalone is in the grow-out arrangement they feed on algae that collect and grow during that period on the surfaces of the grow-out arrangement and other structures located within the grow-out arrangement. Preferably structures C are disposed in the grow-out arrangement so as to promote algal growth C therefore providing a natural food source to the abalone. This is discussed further below.

The platform depth is chosen so as to optimise the photosynthetic processes of the macro algae settling on the side walls, the base of the platform as well as structures within the structure such as netting and separate habitats, the algae thereon establishing themselves and growing. The set depth of the platform at the will depend upon water clarity and sea conditions. Water clarity can affect the degree of ultra-violet (UV) radiation penetration down to the algae growth region created by the arrangement. Too much UV radiation can adversely affect algae growth. The type of algae will vary from site to site and the target macro algae species will vary for the different abalone species.

Prior to the introduction of abalone, the grow-out arrangement and all components within the grow-out arrangement such as the nets and artificial habitats discussed below are placed in offshore waters for at least six months or until covered with the desired species of algae. Once there is adequate coverage of algae on the grow-out arrangement, the nursery abalone once they have reached 17mm across the widest part of the shell, they can be introduced into the grow-out arrangement. Algae is the primary food source for the abalone therefore the abalone do not need to be fed manufactured or introduced natural feed, such as pellets or kelp, etc. However, prepared feeds IDcan be successfully used if there is algae die back of if stocking density is increased.

SAbalone is introduced at a density that will not require relocation of the abalone 00 as they grow. Preferably algae growth is in excess of abalone consumption of the algae in the first 2 years; therefore the algae will also be established sufficiently to sustain the abalone throughout the third and fourth year of c' abalone residence.

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It will be appreciated that when harvesting the abalone, it is necessary for C' divers to dive into the grow-out arrangement (as depicted in Figure 1) 10 to reach platform 11 where the abalone is growing. As described previously, this adds to the complexity and cost of the farming operation.

Referring now to Figure 2, there is shown a perspective view of an abalone farming arrangement according to a first aspect of the present invention. The arrangement 100 includes buoyant body 130 floating on the body of water 20 or ocean, supporting below the surface of the water, platform 110 having wall 112.

It will be appreciated that the buoyant body 130 can be a single body or may be provided as a number of discrete bodies dispersed appropriately above the platform 110.

Alternatively, in one embodiment buoyant body 130 could be a 400mm polypropylene tube 131 forming a ring. The ring has a diameter of 20m to (in this embodiment having a diameter of 46 metres and a radius of 23 metres).

It will be understood that the arrangement can take on any shape, including square, rectangular or triangular. In practice, a preferred shape is circular. Also preferably the depth of platform 110 below the buoyant body is set between 3m and 7m and in this embodiment it is set to 4 metres.

NO Referring to Figure 2, platform 110, provides a suitable surface for the placement of growing abalone, and is supported from the buoyant body 130 by support o arrangement 120, for example, by ropes or chains 132 connected to one or more other elements such as ropes or chains 134 forming a wall structure 112, wherein 00 the support arrangement is disposed appropriately to keep platform 110 balanced and located at a desired position and depth with respect to the buoyant body 130. The vertical element 134 in this embodiment forms a portion C of the wall 112 that also includes a head rope 136 and a base rope 138 to form a C support frame for a water permeable mesh 114.

8 The platform 110 is preferably made of water permeable material in which the apertures are so small that the platform is almost a solid surface (for example, finely knit mesh such as shade cloth) as far as the abalone are concerned.

Artificial habitats that allow for abalone to seek and find areas of light and shade as well as protection from turbulent waters, can be placed/secured on the upper surface of platform 110 to encourage abalone growth.

It is preferable that the platform 110 has at least some apertures to allow water to pass through the platform as it is raised and lowered within the water.

Preferably the abalone grow-out enclosure is secured to the sea floor by lines and anchors 200 shown on Figure 2 as would be understood by the person skilled in the art taking into consideration the large effective surface area of the structure and the very great pressures that can be applied to the structure by the tide and other ocean movement Float 202 is centrally located and connected to the centre of the platform 112 to provide some support for the weight of the arrangement for the cultivation of marine molluscs. Float 202 is also depicted in Figures 4a, 4b, 5a, 5b and 5c and in particular in Figures 4b and 5c it is depicted laying at an angle as the bottom of IDthe float is no longer being drawn downwards by the weight of the Sarrangement.

Figure 2 shows multiple compartments, two examples of which are 302 and 304 00 located about the perimeter of the arrangement 100 but only extending to about half the radius of the circular arrangement. The compartments are described in greater detail when referring to Figure 3.

Platform 110 has an outer wall 112 to assist in containing the growing abalone.

The wall 112 need not extend up to immediately below the buoyant body 130 r~l which is depicted in Figures 2, 3,4 and 5. A gap between the top of the wall 112 and the underside of the buoyant body is allowable so as to permit seaweed and other floating debris to pass underneath the buoyant body on any side of the arrangement.

The platform can be lowered further into the ocean when UV penetration is greater or for any other suitable reason.

According to the first aspect of the present invention, means for raising the platform 110 are used or provided to allow platform 110 to be raised towards and lowered away from the surface of the water 20. The means in this aspect includes the lengthening or shortening of the rope or chain 132 between the buoyant body 130 and the head rope 136. By shortening the rope or chain 132 so that the platform is raised allows the abalone to be more easily collected by the "farmers", reducing or eliminating the need for divers to dive down to the platform located some 3m-7m below the buoyant body. In another aspect of the invention, the rope or chain 132 extends between the buoyant means 130 and the platform 110 to somewhere along the base rope 138 and element 132 is shortened so that the platform is raised allowing the abalone to easily collected.

Following collection, movement or for any other reason the abalone grow-out platform is moved up the platform can be lowered in the reverse of the manner IDused for being raised. More detail of these procedures is provided in Figures 4 and In the absence of specific means the platform can be raised or lowered by hand 00 although in most cases electrical/mechanical/pneumatic/hydraulic or other driving means are useable to achieve the necessary leverage to raise and lower \the platform.

In practice, the platform raising means 140 could be mounted to the buoyant body 130, or could be separate such as located on a boat or vessel moored C, adjacent the arrangement Means 140 could be a motor device that once actuated, causes ropes or chains 132 and 134 singly or together to lower or raise the platform with respect to the buoyant body.

To allow adjustment for encouraging algae growth, the depth of the platform can be raised and lowered within a 0 to 5-metre range.

The rate of lowering and rising of the platform for the above purpose or other purposes is always dependant on the welfare of the algae and abalone and is judged accordingly by the operator.

Figure 3 shows a perspective view of the arrangement of Figure 2, where like elements are accordingly labelled. The sidewall is shown as a mesh that is used to form two compartments 300 and 302 over a suitable rope framework Compartment 300 is formed by a rear wall being the outer wall 112, an inner wall 304 located at half the radius of the arrangement (approximately 12.5 metres in from the outer wall 112) and two partial radial walls 306 and 308.

Tops of the various walls 112, 304, 306 and 308 are provided with multiple floats 310 wherein the floats are buoyancy matched to support the arrangement below them at a suitable level and to lessen the loading on the buoyant body 130.

O Figure 4a shows a side view of the arrangement of Figures 2 and 3 depicting the o platform 111 at its deepest level with the raising and lowering including a rope 132 tied between the buoyant means 130 and the head rope 136 of the 00 arrangement.

Figure 4b shows a side view of the arrangement of Figure 4a depicting the C bottom platform 111 in a partially raised position with respect to the N arrangement depicted in Figure 4a.

810 Figures 4a and 4b depict the situation where manual means is used to raise the platform 110 for harvesting of the abalone so that the platform's maximum depth is approximately 2 metres below the buoyant body 130. In this raised condition the arrangement is configured for ease of harvesting. Once abalones are harvested, manual means may be used to lower the platform 110 back to a desired depth for growing a new colony of abalone or the re-establishment of algae.

Figure 5a shows a side view of the arrangement of Figures 2 and 3 depicting the bottom platform 111 at its deepest level with the raising and lowering means including a rope 132 tied between the buoyant means 130 and the base rope 136 of the arrangement; Figure 5b shows a side view of the arrangement of Figure 5a depicting the bottom platform in a partially raised position with respect to the arrangement depicted in Figure 5a; and Figure 5c shows a side view of the arrangement of Figure 5a depicting the bottom platform in an almost fully raised position with respect to the arrangement depicted in Figure 5a. In this case, wall 112 is made from flexible and collapsible mesh material, which collapses as platform 110 is raised towards ND the buoyant body 130. In this raised condition the arrangement is configured for Sease of harvesting as well as movement of the raised arrangement by towing.

Although a preferred embodiment of the apparatus of the present invention has 00 been described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing C-i from the scope of the invention. Modifications and variations such as would be C- apparent to a skilled addressee are deemed within the scope of the present 10 invention.

Claims (10)

1. An arrangement for the cultivation of marine molluscs in a body of Swater, the arrangement including: 00 a platform for supporting the molluscs in use a buoyant body, which in use floats on the surface of the body of water, for supporting the platform below the buoyant body; wherein cl the platform is able to be moved towards or away from the buoyant o body.

2. An arrangement according to claim I further comprises means for moving the platform towards or away from the buoyant body.

3. An arrangement according to claim 2 wherein the means for moving the platform is located at or above the surface of the body of water to allow convenient access.

4. An arrangement according to claim 2 wherein the means for moving the platform is disposed on the arrangement itself.

An arrangement according to claim I wherein the buoyant body defines a ring commensurate with the perimeter of the platform.

6. An arrangement according to claim i further comprises a wall is disposed between the buoyant body and the platform.

7. An arrangement according to claim 6 wherein the wall is made from netting disposed between the platform and the buoyant body.

8. An arrangement according to claim 7 wherein the netting collapses upon moving the platform towards the buoyant body. ID O

9. A method of cultivating algae for the feeding of marine molluscs in a 0 body of water using a platform for supporting the molluscs that is adjustably supported below a buoyant body floating on the surface of the body of water 00 including the step of adjusting the depth of the platform in the body of water to adjust for the effect of ultra-violet radiation on the growth of algae on and about the platform. CI

10. An arrangement for the cultivation of marine molluscs in a body of water substantially as hereinbefore described with reference to and as illustrated in figures 2, 3 and 4 of the accompanying drawings.