AU593168B2

AU593168B2 - Oyster cultivating equipment and method

Info

Publication number: AU593168B2
Application number: AU18514/88A
Authority: AU
Inventors: Lawrence Blankfield
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-07-08
Filing date: 1988-06-29
Publication date: 1990-02-01
Anticipated expiration: 2008-06-29
Also published as: AU1851488A

Description

r- 4,,_AU T A LIA g- 593168 Form PATENTS ACT 1952-1973 COMPLETE SPECIFICATION

(ORIGIIHAL)

FOR OFFICE USE Class: I t. Cl: plication Number: Lodged: (*41 '(Sr (1 St 5 1 s Si S S S 5 S 5* S S S 5* nplete 10;-ecification-Lodged: Accepted: Published: LThis dftcurent contains the arnndments made undt.r Section 49 and is correct for riting.

rity: ated Art: St ~TO BE COMPLETED BY APPLICANT me of Applicant: A\ddres,9 of Applicant: -LAWREIICV, BLANKFIELD 1 Oyster Lane, Lake Wonboyn, New Southi Wales, 2551, Australia Actual Inventor,, Address 'ror Service: LAWRENCE BLANKFIELD JOHN L-DAVIES, CO.

P..i~ox 436 39 Cheviot Rd.) Mt. Waverley, Vivztoria, 3149 Complete Specification for the inveiiltlon entitled: 'OYSTER CULTIVATING EQUIPMENT AND METHOD" The following statemnent Is a full dlescr~ption of this invention, including the best method of performing it known to me.- *Note; The description Is to be typed in double spacing, pica type fave, in an area not exceeding 250 mm In depth itd 160 mm In width, on tough white paper of good qlunlity' and it is to be inserted trslde thjG form.

11710/76-L 11710/76-LF. D. Atkinson, Government Printer, Conberr' 47 This invention relates generally to methods and equipment used in seafood oyster farming and more particularly concerns a floating, oyster-containing, floatable cage device for cultivating and harvesting oysters for seafood.

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#4 Oysters are commonly cultivated on oyster farms in brackish salt water of shallow inlets, mainly using what is known as a rack and rail system wherein fixed horizontal wooden rails are fixed to wooden posts embedded in a mud in or sand bottom, the rails being suspended above the bottom between posts at a height sufficient to maintain submerged condition, oysters attached to sticks or on trays placed across the rails. In such arrangements under certain conditions, severe losses of oysters take place, such as by rough water or prolonged very low tides and high temperatures, predation and the like.

.4 It is an object of this invention to provide apparatus for cultivating seafood oysters.

Another object is to provide a method of cultivating seafood oysters.

The invention, according to a general aspect therefore resides in apparatus for cultivating oysters which compri.ses a floatable cage adapted to hold and protect oysters while submerged in salt water at an oyster farm, releasable mooring means being provided for mooring the S cage to pegs, rails, ropes, cables and the like for main- S taining the cage in submerged position in shallow water above the mud or sand bottom of an inlet, estuary or the like, while allowing the crge to rise and fall with tidal water levels, while still submerged.

Preferably, the floatable cage is in the form of a shallow rectangular envelope of open-mesh structure, the mesh apparatus being sufficient to retain oysters while allowing passage of sea water into and out of the cage, the mesh being formed as flat tube with an open end and a closed end, the open end being closable by a fold-over flap as an integral extension of mesh materi;al tied with ties or a catch.

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~1 -2- Preferably, the floatable cage is provided with at least one buoyancy float and more preferablyfJ 3ats are provided in the form of identical, cylindrical tubes sealed at each end and arranged along each longitudinal side edge or wall of the floatable cage, the ends of each float are flattened and solid and are provided with an eye hole for securement of an anchorage.

Alternatively, t' e mesh material is itself floatable and weights are added subtracted to alter the buoyancy according to t oyster load, especially after cultivation has ceased and Ir harvesting of the oysters.

Alternatively, the floatable cage is constructed wholly or partly of perforate sheet material or wickerwork, such as those used for crayfish pots, or wire netting.

Preferably, the floatable cage has mooring means comprising an equal length of elongate, pliable material, such as a rope or chain with one end attached to each corner of the flotable cage, the other end being attached to oyster fa t suspension rails, the length of the mooring means being sufficient to allow submergence of the cage without Srsting on, or near the bottom and to allow the cage to rise and fall with tidal water levels while still submerged.

Preferably, the mooring means is in the form of eyes, on or adjacent the end of each float with one end of a rope, line or chain or the like, passed through, or attached to each eye and the other being fastened to support rails or ropes.

The invention, according to another aspect resides in a method of cultivating and harvesting oysters in an oyster farm, the method comprising placing oyster spats in a floating cage and submerging the spats and oysters during growth thereof in shallow sea water and maintaining the oysters in a submerged state by means for mooring the floating cage by mooring means, such as lines, ropes or chains from the sides or corners of the cage to pegs, rails or main support lines supported by posts to allow the cage to rise and fall with tidal movement and removing the 3-

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mooring means and towing the cage as a raft from the cultivating site to shore to allow oysters to be removed from the cage raft, when the raft is beached.

Preferably, in the above method, the length of the mooring lines can be adjusted in situ by means of looped ends which may be fastened to and unfastened from cleats or the like, fixed to pegs, rails or the like.

A non-limitative example of a practical arrangement of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a plan view of the floatable oyster cage in accordance with the invention.

Referring to the drawings, there is shown in Figure 1, a device for protecting !y encapsulating seafood oyaters during cultivatioin thereof and which comprises a floatable cage preferably in the form of a flat rectangular-shaped envelope of open mesh structure 10, such as a square matrix pattern of synthetic polymeric material, for example ultra-violet light resistant black polyethylene rectangular Smesh. The mesh is formed as a flat tube with an open end and a closed end, the open and closed end thereof being closable by a flap 11, tied with ties 12, 13. The mesh S is attached to, or formed integrally with side floats 14, in the form of two identical, cylindrical tubes sealed at each end and arranged along each longitudinal side edge or wall of the cage envelope. Alternatively, the tubes may be of rectangular cross-section. If the floats are formed separately, then they can be tied to the mesh, or vice versa with either releasable or non-releasable 30 ties, such as those designated 16, 17, 18, 19. Both ends of each tube float are solid and flattened and provided with a hole or eye 14, 14a, 15, 15a respectively for attachment of a mooring member, whereby each corner of the mesh cage can be attached to oyster farm suspension rails 20, 21 by a mooring line in the form of chains 22, 23, 24, respectively, each line or chain having -uffiLient slack to allow the floats to rise and fall with the tides

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r I and to drop down for a sufficient height in extreme low tide or in hot conditions to allow the floatable cage to be sufficiently submerged to maintain oysters within the cage at a tolerable temperature and submerged to a sufficient depth. The buoyancy of the entire device when filled with oysters and the length of the mooring lines is sufficient to keep the oysters submerged below the water line during flucuations in levels of sea water and also to keep the oysters above and clear of the bottom to prevent suffocatsa tion in mud or excess sand, The detachable mooring lines rere or chains can be of adjustable length, or alternatively, the length can be fixed and a series of cleats 26, 27, 28, 29, shown in Figures I and 2, at one or top level, or fur- "o ther cleats, such as those designated 26a and 28a in Figure can be fixed at different height levels on support posts or pegs 30, 31 at oyster farms. The mooring lines can be detached from the floatable cage or from the posts, pegs or rails and the whole device can be towed away as a barge from the oyster cultivating site for unloading of mature Soysters and then recharging with young oyster spats.

Instead of support rails, ropes or cables can be used to support the floating cages and the whole oyster farm can then be removed by towing using the support ropes or cables. The mooring line can be rope, cable or S chain whether of metal or synthetic salt water resistant polymeric material. Wire mesh can be used instead of plastic mesh for the floating cage, or perforate sheet ,Daterial can be used.

The method of cultivating and harvesting oysters according to the invention comprises placing young oysters spats into the floating cage 10 with the flap door 11 of the openable end open, then tying up the flap to the mesh I of the cage with ties 12, 13, usually with some overlap and submerging t,'e spats (and oysters during the growth thereof) in shallow sea water, such as that in estuaries and above the sand or mud thereof and below the surface of shallow sea water and maintaining the growing oysters in a submerged state by mooring the floating cage 10 with detach-

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,able mooring means such as lines, ropes cables or chains 22, 23, 24, 25, attached to the sides or corners of the cage 10 from corner eyelets 14a, 14b, 15a, 15b, tp pegs 31, Figure rails 20, 21 Figure or main support lines to allow the floating cage 10 to rise and fall with tidal movement and then removinlg the mooring means from the cage and towing the cage as a raft to the shore from the cultivating site to allow mature oysters to be removed from the floating cage when beached which is then recharged with sprats.

Preferably, the length of the mooring lines, S ropes, cables or chains can be adjusted in situ while the s floating cage is floating on site, the adjustment being made by placing looped ends, such as the last links (if the chains 22, 23, 24, 25 onto cleats 26, 27, 28, 29 sho-vn in Figure 1, fixed to rails 20, 21, or the like or on pegs 31, shown in Figure 2. The looped ends can be removed from the cleats for adjustment.

S The invention according to another aspect also resides in a method of cultivating oysters in an oyster farm prior to harvesting, which comprises placing oyster sprats in a floating cage and submerging the cage and tprats and oysters during the growth thereof in shallow sea water by mooring the floating cage by mooring means such as lines, ropes or chains attached between sides or corners of the cage and pegs, rails or main support lines on posts, the mooring means being sufficient in lenptn and slack to allow the cage to rise or fall with tidal movement and preferably being adjustable in length in situ by mean a of looped ends which can be fastened to and unfastened from cleats or the like fixed to pegs, rails or the like.

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Claims

1. Apparatus for cultivating and harvesting of oysters 1%w encloso mesAs. enteAcoe- which comprises a>floatable cage, adapted to hold and protect oysters while submerged in salt water at an oyster farm, releasable mooring means being provided for mooring the cage to pegs, rails, ropes, cables and the like and for M maintaining the cage in submerged position in shallow water above the mud or sand bottom of an inlet, estuary or the like, while allowing the cage to rise and fall with tidal water levels, while still submerged.

S2. Apparatus according to claim 1, wherein the float- able cage is in the form of a shallow rectangular envelope of open-mesh structure, the mesh apparatus being sufficient to retain oysters while allowing passage of sea water into and out of the cage.

3. Apparatus according to claim 1 or 2, wherein the mesh is formed as a flat tube with an open end and a closed end, the open end thereof being cloiable by a fold-over flay integral extension of mesh material tied with ties, or a catch.

4. Apparatus 'ording to any preceding claim wherein the floatable cage is provided with at least one buoyancy float.

Apparatus according to claim 4, wherein 4-e two floats are provided in the form of identical, cylindrical tubes sealed at each end and arranged along each lOngitudi- nal sideedge or wall of the floatable cage.

6. Apparatus according to claim 4 or 5, wherein the end of each tube is flattened and solid and provided with an eye hole for securement therethrough of an anchorage.

7. Apparatus according to claim 1 to 3, wherein the mesh material is itself floatable and weights are added or subtracted to alter the buoyancy according to the oyster load, especially after cultivation has ceased and for harvesting o: the oysters. -7- P lll 13 1( 1~ 9)~

8. Apparatus according to any preceding claim wherein the floatable cage is constructed wholly or partly of perforate sheet material.

9. Apparatus according to any preceding claim wherein the floating cage is constructed of wickerwork such as that used for crayfish pots, or is constructed of wire netting.

Apparatue according to any preceding claim wherein the floatable cage has mooring means comprising an equal length of elongate, pliable material, such as a rope or chain with one end attached to each corner of the floatable cage, the other end being attached to oyster farm suspens- ion rails, the length of the mooring means being sufficient to allow submergence of the cage without resting on or too S near a muddy or sandy bottom and to allow the cage to rise and fall with tidal water levels while still submerged.

11. Apparatus according to claim 10 wherein the mooring means is in the form of eyes on, or adjacent the end of of each float with one end of a rope, line, chain or the like passed through or attached to each eye, the other end being fastened to support rails, lines, ropes or cables.

12. A method of cultivating oysters in an oyster farm ei\o\abc^ ves^ eaAe\ope which comprises placing oyster sprats in a floating cage and submerging the sprats and oysters during growth thereof in shallow sea water and maintaining thesprats and oysters in the submerged stateqby means for mooring the cage such as lines, ropes or chains attached to and extending from sides or corners of the cage to pegs, rails or main supp- ort lines to allow the cage to rise and fall with tidal movement, the length or slack of the lines, ropes or chains being such as to allow the sprats and oysters to remain submerged during growth thereof.

13. A method according to claim 12, wherein the length of the mooring lines can be adjusted in situ by means of looped ends which may be fastened to and unfastended from cleats or the like, fixed to pegs, rails or the like. -8- WP DII-~Y. i I- 6 S 0J I Sr 0 0re

14. A method of cultivating and harvesting oysters in an oyster farm which comprises placing oyster sprats in a floating cage and submerging the cage and the sprats and oysters during the! growth thereof in shallow sea water and maintaining the sprats and oysters grown therefrom in a submerged state above a sandy or muddy bottom by means for mooring the cage such as lines, ropes or chains attached to and extending from sides, corners or ends of the cage to pegs, rails or main support lines to allow the cage to rise and fall with tidal movement, the length or slack of the lines, ropes or chains being such as to allow the sprats and oysters to remain submerged during growth thereof and detaching the lines, ropes or chains mooring means from fixed pegs or rails and cleats and towing the cage as a raft from the cultivating site to shore for removal of oysters when the raft is beached.

Apparatus for cultivating and harvesting oysters substantially as hereinbefore decribed with reference to the accompanying drawings.

16. A method of cultivating and harvesting oysters substantially as hereinbefore described with reference to the accompanying drawings.

17. Apparatus for cultivating oysters substantially as hereinbefore described with reference to the accompanying drawings.

18. A method of cultivating oysters substantially as hereinbefore described with reference to the accompanying drawings. DATED this 28th day of June, 1988 LAWRENCE BLANKFIELD By His Patent Attorney: JOHN L.DAVIES CO. -9-