WO1999041976A2

WO1999041976A2 - Fish farming

Info

Publication number: WO1999041976A2
Application number: PCT/IE1999/000010
Authority: WO
Inventors: Terence Nolan; Thomas O'neill; Thomas Murphy
Original assignee: Terence Nolan; Neill Thomas O; Thomas Murphy
Priority date: 1998-02-19
Filing date: 1999-02-19
Publication date: 1999-08-26
Also published as: WO1999041976A3; AU2636199A

Abstract

Fish treating apparatus (1) comprises a treatment tank (2) containing a treatment medium. The tank (2) has an inlet (3) for fish to be treated and an outlet (4) for treated fish. The tank (2) is divided into six separate volumes (Y1, Y2, Y3, Y4, Y5, Y6), by partitions (71, 72, 73, 74, 75, 76) of mesh material which extend radially outwardly from a central hub. The hub is rotated by a handle (100) to progressively present the volumes to a fish inlet line (34). The inlet fish are dewatered at an inlet dewatering station (45) and washed in washing stations (46, 47, 48). Outlet fish are also dewatered at an outlet dewatering station (50) and washed at washing stations (51, 52, 53) prior to return to a fish farming enclosure. Wash water is recycled between the various stages to optimise water usage.

Description

"Fish Farming"

Introduction

The invention relates to an improved method and apparatus for preventing and/ or treating diseases, infections or infestations in fish such as salmon, especially in an intensive fish cultivating environment.

There are several problems caused by disease in fish farming. Because of the intensive environment, if an infection is introduced it spreads extremely rapidly and can affect a large number of fish, and in extreme situations the entire fish population in a farm. Of particular concern are external parasites, gill parasites and protazoas.

There are a number of ways of preventing or treating such infestations in seawater. In one known arrangement a tarpaulin is placed around a enclosure and the bottom of the net of the enclosure is drawn up to reduce the volume. The therapeutant is then introduced into the top space and oxygenated. On completion, the bottom of the net is dropped, the tarpaulin removed and the sea washes away the therapeutants. The release of such therapeutants has the potential for adversely affecting the environment. In addition, the treatment environment is susceptible to wide variations caused by site conditions including currents, waves, tides and the like.

There is therefore a need for a method and apparatus for treating fish especially in an intensive fish farming environment, which will overcome at least some of these problems. Statements of Invention

According to one aspect the invention provides a fish treating apparatus comprising a treatment tank providing a controlled environment for a treatment medium, the treatment tank having an inlet for fish to be treated and an outlet for treated fish.

In one embodiment of the invention the fish treating apparatus includes buoyancy means to maintain flotation and stability of the tank.

In another embodiment the fish treating apparatus includes a floatable support structure to which the tank is attached. Preferably the tank is pivotally mounted to the support structure. Most preferably the tank is pivotally mounted to the support structure about generally horizontal hinge axes. Ideally the tank is pivotally mounted to the support structure at at least three points.

In a further embodiment of the invention the support structure comprises support hulls and a decking mounted on the hulls. Preferably there are a pair of spaced- apart support hulls and a support decking extending therebetween.

In another aspect the invention provides a fish treating apparatus including an onboard water quality control system. Preferably the water quality control system includes a water circuit comprising a treatment tank water inlet, a treatment tank waste water outlet filtration means for removal of contaminants from the waste water and means of oxygenating the water. Most preferably the water quality control apparatus includes a dosing station for maintaining a desired level of therapeutant in the fish treatment tank.

In a preferred embodiment of the invention the fish treatment apparatus includes inlet fish washing means for washing the fish prior to delivery into the treatment tank. In this case preferably the inlet fish washing means comprises a dewatering station and at least one washing station downstream of the dewatering station. Ideally there are at least two and preferably three separate washing stations downstream of the dewatering station. In this case the travel of inlet fish along the dewatering and/ or washing station(s) is assisted by gravity flow.

Preferably the fish treatment apparatus also includes outlet fish washing means for washing the treated fish prior to re-introduction into their habitat. Preferably the outlet fish washing means comprises a dewatering station and at least one washing station upstream of the dewatering station.

Ideally there are at least two and preferably three washing stations upstream of the dewatering station. The travel of outlet fish along the washing station(s) and/or outlet dewatering station is preferably assisted by gravity flow.

In a particularly preferred embodiment of the invention water removed in dewatering and/ or washing stations is re-used. The recycled water is preferably used as supply to other dewatering and/or washing station(s).

In an especially preferred embodiment of the invention the fish treatment tank is provided with means for moving fish through the tank. Ideally the fish moving means comprises a movable partition within the tank. In a particularly preferred embodiment of the invention the tank is divided by a partition. Preferably the tank is sub-divided by a number of partitions, some or all of which may be movable in the tank. Particularly preferred is the case wherein the partitions are movable to progressively advance the fish through the tank.

Preferably the partition extends generally radially from a central hub in the tank. In this case a number of spaced-apart partitions extend radially outwardly of the hub. Ideally the hub is rotatable in the tank to move the fish through the tank. In a preferred arrangement the or each partition is defined by a mesh structure to move the fish through the tank. Ideally the partition includes edge brush means for brushing the inner surface of the tank as the partition is being moved to seal the space and move the fish away from the tank walls as the partition is being moved. In this way fish are confined within the partitions.

In this case the central hub is defined by a plurality of mesh supporting bars which are mounted to support rings at the centre of the tank. There may be a lower support ring adjacent a base of the tank and an upper support ring adjacent an upper end of the tank. Preferably the lower support ring is supported on a floor of the tank. In this case the lower supporting ring has an inner guide ring which is supported on the floor of the tank by support feet, the outer support ring being rotatable relative to the inner guide ring.

Preferably the upper support ring is mounted within an upper guide ring, the upper support ring being rotatable relative to the upper guide ring on rotation of the hub.

In a preferred embodiment of the invention buoyancy means is provided for maintaining the hub in position in the tank. The buoyancy means may comprise blocks of buoyancy material or a tank attached to the hub at the upper end thereof.

In one embodiment of the invention the hub includes an attachment for rotation thereof. Typically the attachment comprises an operator handle.

The invention further provides a method of treating fish in a fish farming environment comprising the steps of locating a fish treating container adjacent to a fish farming enclosure, drawing fish from the enclosure into the container, treating the fish in the container and returning the treated fish to the enclosure. Preferably the container has a number of treatment areas and the method includes the step of moving the fish between the treatment areas, during treatment.

Treatment generally requires a specified time in the therapeutant. Dividing the treatment tank into a number of compartments by using partitions, increases the quantity of fish that can be treated in any given time. The residence time in the therapeutant is determined from the last fish in.

In an especially preferred aspect the invention provides a floatable movable fish enclosure with a controlled environment that may be divided by partitions /baffles into separate compartments, the enclosure having:-

means for washing the fish before entering the enclosure and on exiting the enclosure;

means of transferring fish from their habitat into the enclosure, from the enclosure back to their habitat; and

means for maintaining the water quality within the environment.

Brief Description of the Drawings

The invention will be more clearly understood from the following description thereof, given by way of example only, with reference to the accompanying drawings, in which: -

Fig. 1 is a side view of a fish treatment apparatus of the invention in position of use;

Fig. 2 is a plan view of the apparatus of Fig. 1; Fig. 3 is a perspective view of a raft part of the fish treatment apparatus;

Fig. 4 is a transverse cross sectional view of the raft of Fig. 3;

Fig. 5 is a transverse cross sectional view of a tank part of the apparatus;

Fig. 6 is a perspective view of a partition system used in the tank;

Fig. 7 is a perspective view of a portion of a bottom section of the partition system;

Fig. 8 is a perspective view of a portion of an upper section of the partition system with an upper section of netting removed;

Fig. 9 is a top plan view of the partition system;

Fig. 10 is a plan view at the base of the partition system;

Fig. 11 is a side view of the fish treatment apparatus illustrating the water treatment circuit used;

Fig. 12 is a perspective view of a filter forming part of the water treatment circuit of Fig. 11;

Fig. 13 is a top plan view of the fish treatment apparatus, illustrating the fish handling system used in the invention; and

Fig. 14 shows diagrammatic views illustrating the deployment of the fish treating tank, in use. Detailed Description

Referring to the drawings there is illustrated a fish treating apparatus 1 comprising a treatment tank 2 providing a controlled environment for a fish treatment medium. The treatment tank 2 has an inlet 3 for fish to be treated and an outlet 4 for treated fish.

The treating apparatus 1 includes buoyancy means to maintain floatation of the tank 2. In this case the apparatus 1 includes a floatable support structure 5 to which the tank 2 is attached. The floatable support structure is illustrated particularly in Figs 3 and 4 and comprises a pair of side support hulls 10, 11 and a support decking 12 mounted to the hulls 10, 11. The tank 2 is mounted to the support structure 5 at three connection points 13, 14, 15. This mounting system allows the tank 2 to be readily mounted/ demounted from the support structure 5 while ensuring that the tank 2 is rigidly mounted to the support structures.

The fish treating apparatus includes an on-board water treatment system to provide a controlled environment for a fish treatment medium. Referring in particular to Figs 11 and 12 a water treatment system 20 is mounted on the support structure 5. Dosing means for introducing a therapeutant into the water is provided. The treatment medium thus produced is delivered into the treatment tank 2 along an inlet delivery line 21. Return water from tank 2 flows by gravity to a drum screen filter 27, carrying solid waste which has collected in a sump area 25 of the tank 2. The drum screen filter inlet is below water level. Water which passes through the drum screen filter 27 is delivered through a recycle line 28 to the water treatment system before being returned to the tank 2. In this way the quality of the treatment medium is assured. Therapeutant is introduced in an amount to maintain a desired therapeutant concentration in the treatment tank 2.

In use, the treatment apparatus 1 is towed to a position adjacent a fish farm enclosure and fish from the fish farm enclosure are delivered from a fish inlet 30 through a fish washing means 35 and into the tank 2 through a fish delivery line 34. The fish are drawn from the enclosure by a conventional fish pump 36 which is operated by a separate water supply 37.

Similarly, treated fish are drawn from the tank 2 by a fish pump 40 which delivers the outlet fish through an outlet fish washing means 41 for return to the same or a different fish farm enclosure through an outlet 42.

Referring in particular to Figs 2 and 13, the inlet fish washing means 35 comprises a dewatering station 45 and three separate washing stations 46, 47, 48 arranged in series downstream of the dewatering station 45. The fish are passed through an open tunnel formed by a plurality of bars which are spaced-apart for a sufficient distance to allow water through but to prevent fish from falling through the bars. The tunnel is inclined downwardly so that the fish flow by gravity through the washing means 35. Each of the washing stations 46, 47, 48 has a spray means for application of spray water to wash the fish. As will be described in more detail below water usage and washing/ dewatering is optimised by collecting water from the various stages and re-using the water.

The outlet fish washing means 41 comprises a dewatering station 50 and three separate washing stations 51, 52, 53 arranged in series downstream of the outlet dewatering station 50. The dewatering and washing stations are as described above in relation to washing of inlet fish.

Water removed in the inlet dewatering station 45 is sea water and is discharged back to sea through a return line 55 and filter. Similarly, water removed at the outlet dewatering station 50 is tank water and is returned to a stilling chamber 60 at the middle top of the tank 2 along a return line 61. The stilling chamber has the effect of calming the return water as it is returned into the tank 2. Wash water for the first inlet washing stage 46 is provided by wash water collected from the second outlet washing stage 52 which is delivered through a first wash recycle line 63. Similarly, wash water for the second inlet washing stage 47 is provided by wash water collected from the first outlet washing stage 51 along a second wash recycle line 64. Wash water from the second inlet washing stage 47 is collected and delivered along a third wash water recycle line 65 to provide a wash water supply to the second oudet washing stage 52. Water for the final inlet washing stage 48 is provided from the supply line 21 and wash water is collected and delivered along a further wash water recycle line 66 to the first outlet washing station 51. Wash water from the first inlet washing stage 46 is delivered along a further wash water recycle line 67 to supply the final outlet washing stage 53. In this way water utilisation is optimised and high levels of therapeutant are not released.

Referring now particularly to Figs 5 to 10 the tank 2 is divided by partitions. Means are provided for moving the fish through the tanks and in this case the fish moving means comprises a movable partition in the tank. In more detail the tank

2 is divided into six volumes by six partitions 71, 72, 73, 74, 75, 76 formed of mesh material each having top and bottom radial support bars 77, 78 interconnected by an outer vertical support 79. The mesh partitions 71, 72, 73,74, 75, 76, are connected at their inner end by mesh connecting clips 80 to a central mesh 81 which in turn is fixedly mounted by clips 84 to a plurality of circumferentially spaced-apart rods 82. The mesh supports 77, 78, 79 are also interconnected by upper and lower support hoop sections 83.

The central mesh support rods 82 extend between a lower support ring 87, an intermediate support ring 88 and an upper support ring 89. The radial support bars

77 are connected to the lower support ring 87 and the radial support bars 78 are connected to the intermediate support ring 88. The rings 87, 88, 89 with the attached mesh 81 define a central hub which is rotatable in the tank 2. At the lower end of the tank 2 the lower support ring 87 is rotatable relative to an inner guide ring 90 which is mounted by support legs 91 to the base of the tank 2. Similarly, the upper support ring 89 is rotatable relative to an outer guide ring 95. Guides 96 extend between the rings 89, 95.

An attachment for rotation of the hub is provided by a handle 100 attached to the upper support ring. On rotation of the handle 100 the partitions 71, 72, 73 ,74, 75,

76, are movable through the tank 2. Buoyancy means for maintaining the hub in position in the tank 2 is provided by a block 105 of a suitable buoyancy material or buoyancy tank located below the intermediate support ring. The block 105 includes a central opening 106 for water flow.

A mesh netting 110 also extends across the base between the partitions to provide the sump area 25 at the base of the tank 2 which is not accessible to fish.

To ensure that fish are moved evenly on rotation of the hub, edge brush means 120 are provided for brushing the inner surface of the tank as the partitions are being moved. The brushes 120 assist in moving the fish which are adjacent the tank walls and to seal the space between the partitions 71 to 78 and the side wall the underside of the top of the tank 2.

The buoyancy of the tank 2 is also assisted by a head section 125 of watertight compartments or of a suitable buoyant material. The deployment of the tank in water is diagrammatically illustrated in Fig. 14. When the tank 2 is empty the normal floating position will be position A. To right the tank into its normal operating position water W is introduced into the tank. As more water is introduced the tank travels through the range of positions illustrated by dotted outline in Figs 14 until the tank is righted.

In use, the apparatus is positioned adjacent a fish rearing enclosure containing fish to be treated. The tank 2 is filled with a treatment medium which comprises water with a desired concentration of therapeutant. The water in the tank 2 is oxygenated and fish are then drawn from a enclosure along the line 30. The inlet fish are dewatered in the dewatering station 45 and flow by gravity through three separate washing stations 46, 47. 48 before delivery into one Yl of the compartments defined by the partitions in the tank 2. When the compartment Yl is filled, pumping is stopped and the operator turns the handle 100 to rotate the hub carrying the partitions until the following compartment Y2 is located at the fish inlet 3. These steps are repeated until compartments Yl to Y5 are filled. The hub is then rotated to present compartment Y6 to the fish inlet 3. Compartment Yl has now been rotated through the tank to the fish outlet 4. Both inlet and outlet fish pumps 36, 40 are operated to load fish into the compartment Y6 while drawing fish from the compartment Yl. The withdrawn fish are delivered through a dewatering station 50 and three washing stages 51, 52, 53 before return to a fish farm enclosure. When compartment Y6 is full Yl is empty and the cycle continues.

The rotation of the partitions which divide the tank into compartments Yl to Y6 optimises the throughput of fish through the treatment cycle and thereby significantly reduces the time required to treat a batch offish.

The treatment system has considerable advantages. Because it is a mobile system it can be easily moved from one enclosure to another. The throughput of fish is optimised and because the system is self contained, it is considerably faster and cheaper to operate than other treatment systems. In the case of fresh water treatment for the paramoeba parasite, the fresh water is contained in a separate tank that is easily moved to a desired treatment site. For other treatments, in which various chemicals are added to the water (fresh or sea), the usage of the chemicals is optimised as they are in a confined re-usable volume of water that can be used across a number of enclosures. The treatment method and apparatus can therefore be used in a very wide range of applications. Many variations on the specific embodiments of the invention will be readily apparent and accordingly, the invention is not limited to the embodiments hereinbefore described which may be varied in detail.

Claims

1. A fish treating apparatus comprising a treatment tank providing a controlled environment for a treatment medium, the treatment tank having an inlet for fish to be treated and an oudet for treated fish.

2. A fish treating apparatus as claimed in claim 1 including buoyancy means to maintain flotation and stability of the tank.

3. A fish treating apparatus as claimed in claim 1 or 2 including a floatable support structure to which the tank is attached.

4. A fish treating system as claimed in claim 3 wherein the tank is pivotally mounted to the support structure.

5. A fish treating apparatus as claimed in claim 4 wherein the tank is pivotally mounted to the support structure about generally horizontal hinge axes.

6. A fish treating apparatus as claimed in claim 4 or 5 wherein the tank is pivotally mounted to the support structure at at least three points.

7. A fish treating apparatus as claimed in any of claims 3 to 6 wherein the support structure comprises support hulls and a deck mounted to the hulls.

8. A fish treating apparatus as claimed in claim 7 comprising a pair of support hulls and a support decking extending therebetween.

9. A fish treating apparatus as claimed in any preceding claim including an on-board water quality control system.

10. Fish treatment apparatus as claimed in claim 9 wherein the water quality control apparatus includes a dosing system, a filter, a treatment tank oxygenation means, and filtration means for removal of contaminants from the water.

11. Fish treatment apparatus as claimed in claim 9 or 10 wherein the water quality control apparatus includes a dosing station for maintaining a desired level of therapeutant in the fish treatment tank.

12. Fish treatment apparatus as claimed in any preceding claim including inlet fish washing means for washing the fish prior to delivery into the treatment tank.

13. Fish treatment apparatus as claimed in claim 12 wherein the inlet fish washing means comprises a dewatering station and at least one washing station downstream of the dewatering station.

14. Fish treatment apparatus as claimed in claim 13 wherein there are at least two and preferably three separate washing stations downstream of the dewatering station.

15. Fish treatment apparatus as claimed in any of claims 12 to 14 wherein the travel of inlet fish along the dewatering and/or washing station(s) is assisted by gravity flow.

16. Fish treatment apparatus as claimed in any preceding claim including outiet fish washing means for washing treated fish prior to re-introduction into their habitat.

17. Fish treating apparatus as claimed in claim 16 wherein the outlet fish washing means comprises a dewatering station and at least one washing station upstream of the dewatering station.

18. Fish treating apparatus as claimed in claim 17 wherein there are at least two and preferably three washing stations upstream of the dewatering station.

19. Fish treatment apparatus as claimed in any of claims 16 to 18 wherein the travel of outlet fish along the washing station (s) and/or outiet dewatering station is assisted by gravity flow.

20. Fish treatment apparatus as claimed in any of claims 12 to 19 wherein water removed in dewatering and/or washing stations is re-used.

21. Fish treatment apparatus as claimed in claim 20 wherein the recycled water is used as supply to another dewatering and/or washing station.

22. Fish treatment apparatus as claimed in any preceding claim wherein the fish treatment tank is provided with means for moving fish through the tank.

23. Fish treatment apparatus as claimed in claim 22 wherein the fish moving means comprises a movable partition within the tank.

24. Fish treatment apparatus as claimed in any preceding claim wherein the tank is divided by a partition.

25. Fish treatment apparatus as claimed in any of claims 22 or 24 wherein the tank is sub-divided by a number of partitions, some or all of which may be movable in the tank.

26. Fish treatment apparatus as claimed in claim 25 wherein the partitions are movable to progressively advance the fish through the tank.

27. Fish treatment apparatus as claimed in any of claims 22 to 26 wherein the partition extends generally radially from a central hub in the tank.

28. A fish treatment apparatus as claimed in claim 27 wherein a number of spaced-apart partitions extend radially outwardly of the hub.

29. A fish treatment apparatus as claimed in claims 27 or 28 wherein the hub is rotatable in the tank to move the fish through the tank.

30. A fish treatment apparatus as claimed in any of claims 22 to 29 wherein the or each partition is defined by a mesh structure to move the fish through the tank.

31. A fish treatment apparatus as claimed in any of claims 22 to 30 wherein the partition includes edge brush means for brushing the inner surface of the tank as the partition is being moved to move fish away from the tank walls as the partition is being moved and to seal the space between the partition and the tank.

32. A fish treatment apparatus as claimed in any of claims 27 to 31 wherein the central hub is defined by a plurality of mesh supporting bars which are mounted to support rings at the centre of the tank.

33. A fish treatment apparatus as claimed in claim 32 including a lower support ring adjacent a base of the tank and an upper support ring adjacent an upper end of the tank.

34. A fish treatment apparatus as claimed in claim 33 wherein the lower supporting ring is supported on a floor of the tank.

35. A fish treatment apparatus as claimed in claim 34 wherein the lower supporting ring has an inner guide ring which is supported on the floor of the tank by support feet and an outer support ring which is rotatable relative to the inner guide ring.

36. A fish treating apparatus as claimed in any of claims 33 to 35 wherein the upper support ring is mounted within an outer guide ring, the upper support ring being rotatable relative to the outer guide ring on rotation of the hub.

37. A fish treating apparatus as claimed in any of claims 27 to 36 wherein buoyancy means is provided for maintaining the hub in 'position in the tank.

38. A fish treating apparatus as claimed in claimed 37 wherein the buoyancy means comprises a block of buoyancy material or a buoyancy chamber between the hub and the tank at the upper end thereof.

39. A fish treating apparatus as claimed in any of claims 27 to 38 wherein the hub includes an attachment for rotation thereof.

40. A fish treating apparatus as claimed in claim 39 wherein the attachment comprises an operator handle.

41. Fish treating apparatus substantially as hereinbefore described with reference to the accompanying drawings.

42. A method of treating fish in a controlled environment comprising the steps of locating a fish treating container adjacent to a fish farming enclosure, drawing fish from the enclosure into the container, treating the fish in the container and returning the treated fish to the enclosure.

43. A method as claimed in claim 41 wherein the container has a number of treatment areas and the method includes the step of moving the fish between the treatment areas, during treatment.

44. A method as claimed in claim 42 or 43 using a fish treatment apparatus as claimed in any of claims 1 to 41.

45. A method of treating fish substantially as hereinbefore described with reference to the accompanying drawings.