WO2009100503A1

WO2009100503A1 - Device for removing marine animals from an aquaculture tank

Info

Publication number: WO2009100503A1
Application number: PCT/AU2009/000176
Authority: WO
Inventors: Ian Mcrobert
Original assignee: Mcrobert Aquaculture Systems Pty Ltd
Priority date: 2008-02-14
Filing date: 2009-02-16
Publication date: 2009-08-20
Also published as: AU2009214838A1

Abstract

A device (10) for handling marine animals (25) comprises a panel or bottom wall (30) having one or more (in this instance four) doors (32), each door (32) moveable between a closed position (shown in Figures 1 and 5) where the doors cover corresponding openings (34) to an extent to prevent a fish (25) from passing therethrough, and an opened position (figures 2 - 4) where the doors uncover the corresponding openings (34) to the extent that fish (25) can pass therethrough. When the doors are open and the device (10) lowered into a tank (14a), fish (25) swim through the openings (34) to lie above the panel (30). The doors (32) can now be closed and the device (10) raised lifting the fish to a position where they can be directed through a channel (20) to an adjoining tank (14b).

Description

DEVICE FOR REMOVING MARINE ANIMALS FROM AN AQUACULTURE TANK

Field of the Invention

The present invention relates to a marine- animal handling device particularly for removing marine animals from an aquaculture tank.

Background of the Invention

Land based aquaculture often involves growing fish or other marine animals in tanks. The marine animals are transferred between tanks on a regular basis for maintenance and cleaning of the tanks and for animal husbandry. The common method used to remove marine animals from a tank involves use of people with scoop nets trying to catch the marine animals within, the tank. Often the tanks are partially drained to make it easier to catch the marine animals .

This method of handling is very inefficient and is known to create stress in the marine animals (particular in the case of fish) which may adversely affect their growth and at times even cause death.

Summary of the Invention

The present invention was developed to provide an alternate device and associated method for handling marine animals.

According to one aspect of the invention there is provided a device for handing marine animals held in a volume of water in a tank having a side wall, the device comprising:

a panel having one or more doors, the or each door moveable between a closed position where the door covers a corresponding opening in the panel to an extent to prevent a marine animal from passing therethrough, and an opened position where the door uncovers a corresponding opening to the extent that a marine animal can pass therethrough.

The device may be configured so that when the panel is raised from the tank with the doors in the closed position no marine animal is able to pass between the device a peripheral edge of the device and the side wall of the tank.

The device may be configured so a footprint area of the or each door is less than a footprint area of the panel.

The device may comprise a marine animal herding system operable to herd marine animals in the tank above the panel into a region having a base area smaller than the footprint area of the panel .

The herding system may comprise two or more radially extending arms, wherein at least one of the arms is moveably coupled to the panel about a central axis of the panel wherein an angular spacing between the arms can be varied.

Both arms may be moveably coupled with the panel .

The or each arm may be coupled with a support extending coaxial with the central axis of the panel.

The or each arm may be provided with apertures configured to allow the passage of water to the exclusion of a marine animal .

The panel including the or each door may be each provided with one or more drains configured to allow passage of water therethrough to the exclusion of a marine animal. However in an alternate embodiment the panel, excluding the or each door, may be provided with one or more drains configured to allow passage of water therethrough to the exclusion of a marine animal.

In yet a further alternate embodiment the panel, excluding the or each door, is liquid impervious. In this embodiment the or each door may be provided with one or more drains configured to allow passage of water therethrough to the exclusion of a marine animal. Further in this embodiment the or each door may be spaced above the panel . Further in this embodiment the device may comprise a side wall extend upright from a peripheral edge of the panel

The or each door may be coupled to the panel in a manner to automatically open when the device is lowered into the tank.

A second aspect of the invention may provide a marine animal handling device comprising: a panel a side wall extending from the panel to form a receptacle, the panel provided with an opening; and, a door coupled to the panel and moveable between a closed position where said door covers said opening, and an opened position where said door uncovers said opening, said door having a footprint area less than a footprint area of the panel .

The door may be centrally located in the panel.

The door may form a substantially liquid tight seal with the panel when in said closed position.

The door may comprise a drain having an outlet spaced by a height D above the panel when said door is in said closed position, so that when said fish handling device is sunk in said body of water with said door in, or moved to, said open position, and said door is subsequently moved to said closed position as said device is lifted from said body of water, water within said receptacle drains from said receptacle through said first drain to a depth substantially equal to the height D.

The door drain may comprise a screen or be otherwise configured to prevent passage of a marine animal therethrough.

The marine animal handling device may further comprise one or more drains for selectively draining any water held within said receptacle.

In each of the above aspects, the device may comprises a grader for grading marine animals on the basis of size to allow marine animals held above the panel of a size smaller than a grading size to pass through the grader to below the panel or bottom wall when the device is being raised within the tank .

A third aspect of the invention may provide an aquaculture system comprising a tank for holding a volume of water and a plurality of marine animals in the water, and a device according to the first aspect, wherein the device is supported to be lowered into and raised form the tank, wherein when the or each door is opened during lowering one or more marine animals can pass through the corresponding openings in the panel to lie above the panel, and wherein on moving the or each door to the closed position and raising the device the marine animals above the panel are raised with the device.

A further aspect of the present invention may provide a method for removing marine animals from a body of water held within the tank said method comprising: providing a marine animal handling device according to the first or second aspect of the invention; sinking said device toward a bottom of said tank with the or each door in said open position to create a flow of water through the corresponding openings so that substantially all of said marine animals within said tank pass through the openings,- moving the or each door to said closed position; and, lifting the device from the bottom of the tank.

Brief Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a representation of a first embodiment of a marine animal handling device in accordance with the invention when incorporated in an aquaculture system,-

Figure 2 is a representation of the device of Figure 1 but with doors of the device in an opened position;

Figure 3 depicts the device being lowered into an aquaculture tank of the aquaculture system,-

Figure 4 depicts the device fully lowered into the tank and with the doors still in the opened position;

Figure 5 depicts the device fully lowered into the tank but with the doors now moved to a closed position;

Figure 6 is a plan view of the device with an incorporated herding system in a herding position; Figure 7 is a perspective view of a second embodiment of the marine animal handling device in accordance with the present invention;

Figure 8 is a plan view of the device depicted in Figure 7;

Figure 9 is an enlarged view of a portion of a side wall of the device shown in Figures 7 and 8; and,

Figures 10-14 depict in sequence the use of the device shown in Figures 7-9.

Detailed Description of Preferred Embodiment

Figures 1-6 depict an embodiment of a device 10 for handling marine animals incorporated in an aguaculture system 12 comprising tanks 14a and 14b (hereinafter referred to in general as "tanks 14") . Each tank has a side wall 16 and a bottom wall 18. A race or channel 20 provides fluid communication between the tanks 14. The channel joins with cut outs 22 formed an upper edge 24 of each side wall 16. Movable gates 26 control the flow of water and passage of marine animals such as fish 25 between the tanks 14 thought the channel 20.

As will be evident from the following description, embodiments of the device 10 enable marine animals in one tank to be herded and directed into the other tank 14. Optionally the device can also be formed to assist in grading the marine animals, or transport them to another tank or location not coupled by a channel 20.

In the embodiment shown in Figures 1-6 the device 10 comprises a panel or bottom wall 30 having one or more (in this instance four) doors 32, each door 32 moveable between a closed position (shown in Figures 1 and 5) where the doors cover corresponding openings 34 to an extent to prevent a fish 25 from passing therethrough, and an opened position (figures 2 - 4) where the doors uncover the corresponding openings 34 to the extent that fish 25 can pass therethrough.

The panel 30 is in the form of a wall or sheet of rigid material in which a plurality of drains or holes 36 are formed allowing water to the exclusion of the fish 25 to pass therethrough. The device 10 is also configured so that when the panel 30 is raised for the tank with the doors 32 in the closed position no fish 25 are able to pass between a peripheral edge 38 of the device and the side wall 16 of the tank 14. This may be achieved by simply making the panel 30 of a configuration so that when it is in a tank 14 there is a small clearance between the panel 30 and an inside surface 40 of the side wall 16, the clearance being too small for the size of the fish 25 in the tank 14 to pass through. Additionally or alternately a brush like structure or seal can be fitted to the peripheral edge which bridges a gap between the edge 38 and inside surface 40.

The device 10 is provided with a fish herding system 42 (see in particular Figures 4 - 6) operable to herd fish in the tank 14 above the panel 30 into a region 44 having a base area smaller than the footprint area of the panel 30.

The herding system 42 comprises two radially extending arms 46. In Figures 1-5 the arms 46 are immediately adjacent each other and thus appear as one, however in Figure 6 the arms are angularly separated and form the region 44. At least one, but more conveniently both, of the arms 46 is moveably coupled to the device 10 about a support in the form of a shaft 48 extending upright co- axial with a central axis of the panel 30. Two sleeves 50 are mounted on the shaft 48, one on top the other. The sleeves are of a height one half the height of the arms 46. An upper half of a radially inner edge of one arm 46 is attached to the upper one of the sleeves 50, and a lower half of the radially inner edge of the other arm 46 is attached to the lower of the sleeves. Thus each of the arms 46 is able to be rotated about the shaft 48 enabling the angular spacing between the arms to be varied, and moreover the region 44 to be aligned with the gate 26.

Each of the arms 46 is provided with apertures 52, which like the holes 36 are configured to allow the passage of water to the exclusion of a marine animal. The apertures 52 reduce the force required to rotate the arms about the shaft 48.

The device 10 is supported on a gantry 54 (see Figure 1) comprising spaced apart vertical legs 56 which are joined at their upper end by two spaced apart and parallel beams 58. A lower end of each leg 56 is coupled to a respective cross bar 60 provided at opposite end with wheels 62. A winch 64 on which is wound a wire line 66 is attached to one of the legs 56. The wire line 66 is guided about a first pulley 68 near a corner of the winch carrying leg 56 and the beams 58, and a second pulley 70 attached to an upright 72 extending centrally from the beams 58. The wire line 66 then passes through a conduit 74 attached to the upright 72 and between the beams 58. An end of the wire line distant the winch 64 is coupled by a shackle 76 (see Figures 4 and 5) to an eye 78 provide at an end of the shaft 48.

When using the device 10, the device 10 may be paced on the ground with the panel 30 laying flat on the ground and the doors 32 in the closed position. The gantry 54 is then wheeled to the device 10, with the conduit 74 roughly aligned with the shaft 48. The winch 64 is operated to pay out the wire line 66 so that the wire line can pass through the conduit 74 and be attached to the shaft 48 using the shackle 76. Next the winch is operated to wind in the wire line 66 to lift the device to a height so that the gantry can be positioned to hold the device 10 in alignment with and above tank 14a, as shown in Figure 1. The doors may now be moved to the opened position as shown in Figure 2 and the winch operated to lower the device into the tank as shown in Figure 3. As this occurs the fish 25 swim through the openings 34 to lie above the panel 30, as shown in Figure 4.

To move the fish 25 to the adjoining tank 14b coupled to the first tank by a channel 20, the doors 32 are first closed, as shown in Figure 5 , and the winch operated to wind in the wire line 66 raising the device 10 away from the bottom wall 18 of the tank 14. The device 10 is raised to a level near a bottom of the channel 20/ gate 26. The gate 26 is now lifted or otherwise opened allowing the fish above the panel 30 to swim through the channel 20 to the adjoining tank 14b. To assist in herding the fish 25 through the gate 26, that arms 46, which initially may have been adjacent each other and disposed diametrically opposite the gate 26, can be rotated in opposite directions so that a radially outer edge of each arm is adjacent respective opposite sides of the gate 26, as shown in Figure 6.

A grading device, not shown may be placed across the gate 26 to allow only fish 25 sufficiently small to pass there through to be transferred from tank 14a to adjoining tank 14b. Fish 25 which are too large to pass through the grader can be effectively maintained in the tank 14a by opening the doors 32 and lifting the device 10 out of the tank 14a. During this process the fish 25 will swim back thought to openings 34 into the water in the tank 14a.

A second embodiment of the device 110 is illustrated with reference to Figures 7-14. Features of the device 110 which are functionally similar to those in the device 10 are denoted with like reference numbers but which are preceeded by the number "1" . The device 110 comprises a panel 130 with a side wall 115 extending upright from its peripheral edge 138 to form a receptacle 113. The panel 130 is provided with a single central door 132 which is coupled to the panel 130 and moveable between a closed position (shown in Figures 7, 8 and 12-14) where the door 132 covers a corresponding opening 134 formed in the panel 130, and an opened position (shown in Figures 10 and 11) where the door 132 is spaced from or uncovers the opening 134. The door 132 is formed with a footprint area less than a footprint area of the panel 130. The panel 130 (excluding the door 132) , unlike the panel 30, is impervious, that is it does not allow water to flow therethrough.

The outer diameter of the panel 130/receptacle 113 is formed to be less than the inner diameter of a tank 114 (see Figure 10) with which it is used to provide clearance with an inside surface 140 of the tank 114. The clearance may be dimension to prevent the passage of a marine animal therethrough. Alternately, brushes or rubber seals 129 may be coupled to an outside surface 127 of the side wall 116 which contact the inside surface 140 of the tank 114. Additionally, stabilisers 131 can be attached at spaced apart locations about the outside surface 127 to centralise the device 110 within the tank 114 as it is being raised and lowered.

The door 132 is attached by a hinge 133 to an upper surface of the panel 130. When the device 110 is lowered into the tank 14 and contacts the water within the tank, the water pushes on the door 132 moving it to the opened position and causing a flow of water through the opening 134 which carries fish 25 into the receptacle 113. Thus, the door 132 opens automatically as the device 110 is lowered into or sunk in the tank 114. The door 132 is also provided with a drain 135 which is spaced by a height D above the panel 130 when the door 132 is in the closed position. This is seen most clearly in Figures 7 and 12-14. The drain 135 is formed by a circumferential wall 137 extending upright of the door 132. An upper end of the wall 137 is closed by a screen or mesh 139. A hole 141 is also formed in the door 132 on the inside of the wall 137. A screen or mesh 143 extends across the hole 141. Screens 139 and 143 allow water to flow through the drain 135 but prevent the passage of fish.

A plurality of struts or straps 166 are attached to the device 110 to enable attachment to a lifting device such a gantry (not shown) .

Figures 10-14 depict a method of use of the device 110. Here, the device 110 is being used to remove all of the fish 25 from a tank 114. In Figure 10, the device 110 is initially lowered into the tank 114. When the device 110 enters the tank 114 it is centralised by the stabilisers 131 with the brushes 129 contacting the inside surface 140 of the tank 114. As the device 110 is sunk to a depth below the level of the water within the tank, the water pushes open the door 132 causing a flow of water through the opening 134 into the receptacle 112. This flow of water carries fish 25 into the receptacle 112. As the device 110 is lowered to the bottom of the tank substantially all of the water and fish within the tank 114 pass through the opening 134 into the receptacle 112.

In order to now remove the fish 25 from the tank 114, the door 132 is moved to the closed position (see Figures 11 and 12) . The door 132 forms a substantial seal with the opening 134 to substantially prevent the leakage of water from between the door 132 and the opening 134. This can be achieved by use of a simple o-ring attached about an under surface of the door 132 which bears against the panel 130 about the periphery of the opening 134. However, as the device 110 is lifted from the tank 114, water above the wall 137 is able to flow back into the tank 114 through the drain 135. The fish 25 are prevented from passing back into the tank 114 by action of the screens 139 and 143.

Figure 13 shows the device 110 raised from the bottom of, but still within the water of the tank 114. Figure 14 shows the device 110 fully lifted out of the tank 114.

When the device 110 is fully lifted from the tank 114 it contains substantially all of the fish 25 originally in the tank 114 together with a volume of water up to a depth D, being the level of the drain 135. The fish 25 can then be transported to a desired location, eg another tank and discharged through the opening 134 upon moving the door 132 to the opened position.

Now that embodiments of the present invention have been described in detail it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. For example, the doors 32/132 are shown as being coupled to the panel 30/130 by way of hinges. However other types of coupling between the doors and panel may be provided. For example the doors 32/132 may be coupled in a manner so as to slide across the openings 34/134. However the hinge connection has the feature of being self opening upon sinking of the device 10/110 into a body of water if the door 32/132 is impervious, or at least comprises a substantial continuous area free of holes .

Also, the device 110 may be provided with an integrated grader for allowing grading of the fish 25. For example a grader comprising a plurality of spaced apart bars of the type described in Applicant's corresponding International application No. PCT/AU03/01157 may be placed in the panel 130 with a sliding cover to open and close the grader. In use, the cover will be placed over the grader when the device 110 is being raised from the bottom of the tank. Once the device 110 has been lifted from the tank, the cover may be opened to allow water and fish of a size smaller than the grading size to flow back into the underlying tank.

In addition, one or more secondary drains may be placed in the panel 130 for draining all of the water from the receptacle 113 after extraction of the fish from the tank 114 to enable weighing of the fish. The secondary drains would typically be either closed when the device 110 is initially sunk in the tank, and then opened if required once the device 110 has been removed from the tank to allow draining of the water to allow weighing of the fish.

The provision of coloured lights and even sonic generators on the underside of panel 30/130 may be incorporated to further assist in directing fish to swim through the opening 34/134 as the device 10/110 is being sunk in the tank

14/114. Alternately the underside of the panel 30/130 may be painted a particular colour known to encourage the breed of marine animal in question to move away from the device 10/110 while it is being lowered, thereby assisting in directing the animals to pass through the openings 34/134.

All such modifications and variations together with others that would be obvious to a person of ordinary skill in the art are deemed to be within the scope of the present invention the nature of which is to be determined from the above description and the appended claims .

Claims

CLAIMS :

1. A device for handing marine animals held in a volume of water in a tank having a side wall, the device comprising: a panel having one or more doors, the or each door moveable between a closed position where the door covers a corresponding opening in the panel to an extent to prevent a marine animal from passing therethrough, and an opened position where the door uncovers a corresponding opening to the extent that a marine animal can pass therethrough.

2. The device according to claim 1 wherein the device is configured so that when the panel is raised from the tank with the doors in the closed position no marine animal is able to pass between a peripheral edge of the device and the side wall of the tank.

3. The device according to claim 1 or 2 wherein a footprint area of the or each door is less than a footprint area of the panel .

4. The device according to any one of claims 1-3 comprising a marine animal herding system operable to herd marine animals in the tank above the panel into a region having a base area smaller than the footprint area of the panel.

5. The device according to claim 4 wherein the herding system comprises two or more radially extending arms, wherein at least one of the arms is moveably coupled to the panel about a central axis of the panel wherein an angular spacing between the arms can be varied.

6. The device according to claim 5 wherein each of the arms is moveably coupled with the panel.

7. The device according to claim 5 or 6 wherein the or each arm is coupled with a support extending coaxial with the central axis of the panel .

8. The device according to any one of claims 5-7 wherein the or each arm is provided with one or more apertures configured to allow the passage of water to the exclusion of a marine animal .

9. The device according to any one of claims 1-8 wherein the panel including the or each door is each provided with one or more drains configured to allow passage of water therethrough to the exclusion of a marine animal.

10. The device according to any one of claims 1-8 wherein the panel, excluding the or each door, is provided with one or more drains configured to allow passage of water therethrough to the exclusion of a marine animal.

11. The device according to any one of claims 1-8 wherein the panel, excluding the or each door, is liquid impervious .

12. The device according to claim 11 wherein the or each door is provided with one or more drains configured to allow passage of water therethrough to the exclusion of a marine animal .

13. The device according to claim 12 wherein the or each drain is spaced above the panel.

14. The device according to claim 13 comprising a side wall extend upright from a peripheral edge of the panel.

15. A marine animal handling device comprising: a panel and a side wall extending from the panel to from a receptacle, the panel being provided with an opening; and, a door coupled to the panel and raoveable between a closed position where the door covers said opening, and an opened position where said door uncovers the opening, the door having a footprint area less than a footprint area of said bottom wall.

16. The device according to claim 15 wherein the door forms a substantially liquid tight seal with the panel when in said closed position.

17. The device according to claim 16 wherein the door comprises a drain having an outlet spaced by a distance D above panel when said door is in said closed position, so that when said fish handling device is sunk in said body of water with said door in or moved to said open position, and said door is subsequently moved to said closed position as said device is lifted from said body of water, water within said receptacle drains from said receptacle through said first drain to a depth substantially equal to the distance D.

18. The device according to claim 17 wherein the drain in the door is configured to prevent passage of a marine animal therethrough.

19. The device according to any one of claims 15-18 comprising one or more drains formed in the panel for selectively draining any water held within said receptacle.

20. An aquaculture system comprising: a tank for holding a volume of water- and a plurality of marine animals in the water; and, a device according to any one of claims 1-19, wherein the device is supported to be lowered into and raised form the tank, wherein when the or each door is opened during lowering one or more marine animals can pass through the corresponding openings in the panel to lie above the panel, and wherein on moving the or each door to the closed position and raising the device the marine animals above the panel are raised with the device.

21. The device or system according to any one of claim 1- 20, comprising a grader for grading marine animals on the basis of size to allow marine animals held above the panel of a size smaller than a grading size to pass through the grader to below the panel when the device is being raised within the tank.

22. A method for removing marine animals from a body of water held within the tank said method comprising: providing a marine animal handling device according to any one of claims 1 - 20; sinking said device toward a bottom of said tank with the or each door in said open position to create a flow of water through the corresponding openings so that substantially all of said marine animals within said tank pass through the openings; moving the or each door to said closed position; and, lifting the device away from the bottom of the tank.