WO2017155414A1

WO2017155414A1 - Fish farm, and method for delousing in a fish farm

Info

Publication number: WO2017155414A1
Application number: PCT/NO2017/050060
Authority: WO
Inventors: Jan Erik KYRKJEBØ
Original assignee: Kyrkjebø Jan Erik
Priority date: 2016-03-07
Filing date: 2017-03-06
Publication date: 2017-09-14
Also published as: NO341377B1; NO20160386A1

Abstract

Fish farm (10) for the farming of fish, comprising a floating collar (12) that floats on the water surface, a net (14) fastened to the floating collar (12) to hold the farmed fish, where the net (14) is also fastened to a bottom ring (24) down in the water, and also a skirt (16) that surrounds the net (14) and which extends down into the water to an area above the bottom ring (24), comprising several flow setters (30) placed standing inside the net (14), where the respective flow setter (30) is comprised of an elongated, vertical suction pipe (36) with a lower inlet (32) for the sucking in of water and an upper, in the main, horizontal outlet (34) to distribute the water in the upper body of water of the net (14) and to set the upper body of water in rotation. Also described is a method for delousing of a fish farm as given.

Description

Fish farm, and method for delousinq in a fish farm. Area of the invention

The present invention relates to fish farm for farming of fish, comprised of a floating collar that floats on the water surface, a net fastened to the floating collar to contain the fish to be farmed, where the net is also fastened to a bottom ring down in the water, and also a skirt that surrounds the net and which stretches down in the water to an area above the bottom ring. Also described is a method for delousing a fish farm as disclosed.

Background to the invention.

Today, the problems of resistant lice and fish escapes as a consequence of delousing and also diseases that spread in the top water layers, are on the increase.

Today there are several known methods in the fight against lice, for one thing, in the farming industry. The industry is still dependent on medication methods where one uses chemicals that create resistance and which kill the fish in complicated delousing operations, and because the fish must be displaced in the delousing operations so that a whole tarpaulin can be pulled around the whole of the net cage. This is a very cumbersome and expensive operation that demands huge resources and several working boats.

In many cases the lice just fall off and do not die, so that they can reproduce or flow with the currents in the surface over to the neighbouring net cage and infect this with lice. In this way the problem will escalate, and as a result a higher and higher number of lice are in the environment and on the fish in the net cages. Today, there are several requirements for more and more installations regarding forced slaughter of the fish because of too high lice levels.

Description of prior art.

Furthermore, it is known that the net cages are equipped with a skirt that is placed on the outside of the net and out beyond the floating collar. This reduces the lice levels somewhat, but it is far from solving the problem as the lice skirt can only be pulled down in an area where there are still lice and due to low oxygen levels in the water surrounded by the lice skirt. It is with this method where only a flow from the water environment outside the net cage is distributed in the net cage, which in turn leads to not enough oxygen being available for the fish.

In that the louse skirt cannot be stretched far enough down in the water layer, this can still lead to large levels of lice and also a shortage of oxygen for the fish, which in turn affects the welfare and growth of the fish. This also leads to reduced flow speed inside the net cage, which in turn reduces the quality of the fish meat and results in a fish with a low resistance and is thus easily infected and dies. Today, during the delousing, the bottom ring, which holds the net out, is pulled up nearly to the surface in a shallow depth. Thereafter, a tarpaulin is pulled underneath and around the whole of the remaining body of the net cage. Thereafter, poisonous chemicals are poured in which shall ensure that the lice drop off the fish. This creates stress and poor welfare for the fish and is also an expensive operation. Firstly, the medical compounds are expensive and, secondly there is a great risk of holes being ripped in the net during the operation and thirdly, the operation requires several working boats and personnel for the job. There is also the threat that the lice can become resistant to these medical compounds. There are also other methods used such as thermal delousing, where the fish is pumped out and through a pipe system using warm water. This is also stressing for the fish and can in turn lead to incidences of disease and mortality because of the stress. With this delousing method, it is necessary to take the fish out of the net cage to subsequently pump it back in again. This is a labour intensive operation and in addition demands expensive equipment such as rafts and cranes. In addition, there is a considerable labour demand to carry this out.

There are also methods known for delousing of salmon lice such as laser, where one lowers one or more laser units down into the net cage which shoot the lice that pass the laser unit. This has still not been a success as it requires large amounts of data to shoot many lice and a large density of fish in front of the laser, and this becomes unnatural as the fish wish to have as homogenous journey as possible in the net cage. The result is that one must have several units per net cage and even then one cannot keep up with an escalation of lice in the net cages. It is also expensive and demanding to have a service and follow up on this method. Also known is a method to use a compressed air driven pump, or electrically driven pump that leads water from the deep to the surface of the net cage, with the idea that infectious lice larvae are carried out of the net cage to hold the body of water in the upper layers approximately free from lice. This solution does not cause a homogenous, even flow in a large area of the net cage and becomes inefficient as a flow setter and agitator for oxygen and will thereby not improve fish welfare to any extent. Here, one aims to drive the pump function with compressed air or as an airlift pump. This is very risky as the fish can be subjected to nitrogen saturation and die. How electrical operation will be solved is not known, but this will regardless not create any rotational flow in the area of the net cage where most of the fish can be found.

And finally, wrasse is used as a non-medical method against salmon lice. This is also an expensive and risky method, primarily because so many wrasses die and that the wrasse can cause a spreading of disease in the net cage. In addition, only one of three wrasses eats lice and they bite the net instead if this is not completely clean. Besides, a wrasse requires a hiding place and its own feed which is costly. Finally, it can also be mentioned that most of the wrasses are not sufficient to keep the level of lice down and that in a lice treatment of the net cage most of the wrasses are killed and new wrasses must be ordered. With the use of wrasses it is possible for an outbreak of virus to emerge suddenly and lead to large losses of fish.

In the industry today, there is no requirement for the collection of waste. Sooner or later this will be required and it is then important to be able to document that one has a standard procedure for collecting the sludge from the net cage. The sludge can also be a resource for biogas, fertilizer and as sustainable fuel to, for example, the cement industry. This also gives the possibility to regulate the feeding in the net cage as one will bring up the excess pellets that the fish do not eat together with the sludge.

NO20140350 A1 shows a closed net cage that is comprised of a watertight canvas that is fastened in a floating collar. The net cage has a further construction/flow setter for circulation of water in the net cage. The flow setter is comprised of a cylindrical pipe with a pump housing that pumps water from, or below, the bottom of the net cage via an inlet in the lower part of the flow setter. The water is pumped out again and through an outlet in the upper part of the net cage. The flow setter can be moved in the vertical direction. In the middle of the bottom of the net cage there is a collecting funnel and from this the waste is pumped out from the net cage through a hose that leads it up to the surface of the ocean on the outside of the net cage. In NO20140350 A1 , a permanently anchored flow setter is shown in a closed installation, where the inlet is place in the body of water underneath the net cage.

NO334957 B describes a net cage with a bottom that can be raised. The bottom ring is fastened to a floating collar with the help of several lines that run from the floating collar and down to the bottom ring. The bottom ring is raised in that the lines are pulled up by one or more winches.

NO327035 B shows a cylindrical, horizontal flow setter that can be used to set up a flow of water in a closed installation. The publication suggests also that the water quality can be further improved in that the flow setter is comprised of equipment to supply oxygen to the water that is running through the flow setter. The flow setter is used in a closed farming tub for the pumping in of water to the tub.

NO329813 B1 shows a fish farm with a collecting funnel at the bottom that collects waste. The funnel is connected to a sludge pipe that extends up to the ocean surface and which sucks waste up from the funnel.

WO2010/050825 A1 and NO20120807 A describe net cages that are surrounded by a de using tarpaulin. The tarpaulin can be raised and lowered whenever needed.

NO336552 B1 describes a semi-submersible net cage with a bottom that can be raised.

Objects of the present invention.

With the present invention one aims to solve the challenges the farming industry faces with respect to lice, escapes and fish welfare in the net cages and at the same time according to the invention aims to be able to collect wastes from the net cages.

With the solution according to the invention one is also secured against escapes in that one can have a double net. A further object is to provide an open net cage with several flow setters that can be flipped up when normal lice treatment is carried out in the net cage and which can also provide a net cage with an improved water quality. Summary of the invention.

Said objects are reached with a fish farm for the farming of fish, comprising a floating collar that floats on the water surface, a net fastened to the floating collar to hold the farmed fish, where the net is also fastened to a bottom ring down in the water, and also a skirt that surrounds the net and which extends down into the water to an area above the bottom ring. Several tiltable flow setters, equipped with a floating collar, are place rigidly connected with each other and standing inside the net, where respective flow setters comprise an elongated, vertical suction pipe with a lower inlet placed in an area below the lower hemline of the skirt for the suction in of water and an upper, in the main, horizontal outlet, to distribute the water in the upper body of the water of the net and to set the upper body of water in rotation.

The outlet is preferably placed in an area under the water surface in the upper body of water.

The floating collars to the respective flow setters can be connected to each other via struts to provide a rigid construction to take up the forces that come from the outlet.

The floating collars of the flow setters and/or any struts can be anchored to the floating collar of the fish farm.

In a particular embodiment three flow setters can be mounted in the fish farm, such that their placing makes up an equilateral triangle. The outlet can be rotary mounted to the suction pipe, both in the horizontal and vertical directions.

The floating collar of the respective flow setters can be articulately connected to the struts and a motor can be mounted to the floating collar to flip up the flow setters into an, in the main, horizontal position. This will be an advantageous position during delousing.

Underneath the net, or in the area underneath the bottom ring, a collection funnel can be arranged that runs down into the water and which is met in a central sludge funnel, from where a sludge pipe runs up to the floating collar. In an alternative embodiment, the outlet to the flow setter can be equipped with one or more nozzle pipes.

Outside the net that holds the fish that shall be farmed, an extra net or canvas that is impermeable to lice can be set up, as the extra net is suspended in the skirt, or in the floating collar of the fish farm.

Furthermore, the flow setters can comprise equipment for the supply of oxygen by injection of oxygen into the suction pipe.

The above mentioned objects are also achieved with a method for delousing in a fish farm for the farming of fish, where the fish farm comprises a floating collar that floats on the water surface, a net fastened to the floating collar to hold the fish that shall be farmed, where the net is also fastened to a bottom ring down in the water, a skirt that surrounds the net and which extends down into the water to an area above the bottom ring, and a collecting funnel suspended underneath the net or the bottom ring and also that the fish farm is comprised of a number of vertically arranged flow setters in the net, as the method comprises that said flow setters, during the raising of the collecting funnel, are tilted and are pulled up, and also raising of the collecting funnel and the bottom ring up to the hemline of the skirt to seal the net cage, followed by delousing in a normal, known way.

During the raising of the collecting funnel, the hemline can be lowered until the skirt meets the collecting funnel.

Furthermore, lice removed from the fish can be collected in the collecting funnel and be sucked up to a destruction unit.

Description of the figures

Preferred embodiments of the invention shall, in the following, be described in more detail with reference to the enclosed figures, in which;

Figure 1 shows a fish farm according to the invention, seen in side outline.

Figure 2 shows correspondingly the fish farm according to the invention during delousing.

Figure 3 shows correspondingly the fish farm according to the invention.

Figure 4 shows correspondingly the fish farm according to the invention, where a part of the net and skirt are removed. Figure 5 shows correspondingly the fish farm according to the invention, seen in top view.

Figure 6 shows correspondingly the fish farm according to the invention seen in top view.

Figure 7 shows a flow setter that is part of the fish farm according to the invention.

Figure 8 shows correspondingly the flow setter that is part of the fish farm according to the invention.

Figure 9 shows the flow setter that is part of the fish farm according to the invention seen in top view.

Figure 10 shows the flow setter that is part of the fish farm according to the invention seen in a raised position in the net cage.

Description of preferred embodiments of the invention.

In principle a net cage for fish farming is described as comprised of a floating collar, a net with a bottom ring, a watertight skirt which preferably goes on the outside of the floating collar and the net, a collection of flow setters fastened to the floating collar, and also a collecting funnel that surrounds the net and the bottom ring and which ends in a funnel that ends up in an outlet at the bottom of the collecting funnel and which is connected to a sludge pump via a hose.

The collecting funnel can be connected with the floating collar via the skirt and can be moved up and down in the net cage partly with the help of a buoyancy ring uppermost in the collecting funnel and via ropes integrated in the skirt.

The flow setters can comprise a vertical suction-pipe trunk, a buoyancy body and a distributor for the purpose of lifting water from deeper layers and distributing this into the top layers of the net cage by setting the upper body of water in rotation. The embodiment example in the figures shows a fish farm 10 with a floating collar 12 equipped with a net 14 and a lice skirt 16 that surrounds the net 14 and which extends down into the water column towards an area where there is little or no lice. The skirt 16 can be made in either a flexible, solid material or a stiffened, flexible material.

The skirt 16 can extend much further down into the water than the standard skirt that is used today, and thereby have a greater effect in that there will be less lice in the fish farm 10, but at the same time can cause a reduction in the water stream and oxygen in the net 14 which in turn can lead to less growth and poorer fish welfare. This is solved according to the invention in that a body of water is brought from the lower layers and preferably below the hemline 16a, but inside the net 14. For this, a number of flow setters 30 placed inside the net 14 can be used, the other functions of which shall be described later, and which are equipped with a vertical suction pipe 36 that preferably extends down past the hemline 16a. The suction pipe 36 is, at its lower part, equipped with an inlet 32 and in the upper part with an outlet 34, where the outlet is preferably placed below the surface of the water 26 in the net cage. Lying between the outlet 34 and the inlet 32 is a propeller 38, waterjet or the like, placed to suck up the water and send it out through the outlet 34.

The flow setters 30 have one or more outlets 34, preferably in an upper layer in the fish farm 10 and the outlet 34 of which can be controlled to set a rotating flow in the net 14 in the whole water layer and which causes a ring chamber-like flow that rotates and establishes an environment rich in oxygen with much flow that the fish will benefit from, and which means that there will be little lice in the net 14 at the same time as the deep skirt 16 will reduce the danger of escapes in that one can have a net and a watertight wall outside as a double safety. The flow setting is illustrated by the arrows in the figures 5 and 6.

The flow is preferably established by several flow setters 30 that are mutually connected to each other to take up the reaction forces that arise and where the collection of flow setters 30 can form a connection or assembly of all flow setters via pipes or struts 42 that lie in or above the surface and which can form buoyancy for the flow setters 30 and thereby be able to relieve for the floating collar 12, in that the assembly of flow setters, or the whole flow system, is fastened directly to this and that the forces which the flow cause do not influence the floating collar to any extent. The flow setters 30 are, as mentioned, put together as vertical suction pipes 36 including a flow propeller 38 or the like in the pipe with a suction end/inlet 32 at the bottom equipped, for example, with a grid and net, and the upper outlet 34 equipped with a pipe bend that can be rotated in the horizontal plane in the water layer in the upper layer of the net cage 14 well above the lower edge of the hemline 16a and which can possibly be controlled from the floating collar 12 to a preferred flow direction. However, the outlet 34 can also be rotated or turned about the horizontal plane, i.e. be flipped up and down. Figures 7 and 8 show in more detail, an example of a flow setter 30. In addition to the previously mentioned construction features, the flow setter 30 can comprise of a tilted wall 46 in the pipe bend, and which usually is held in place by a stand or a frame 48 under a lid 50 in the upper part of the suction pipe 36. The suction means, for example, the propeller 38, can be suspended in said stand 48, where the stand 48, wall 46 and propeller 36 can simply be raised or lowered in the suction pipe 36, as shown in figure 8.

Furthermore, the flow setters 30 can be connected further down toward the suction ends 32 with a net of rope, wire, chain or pipe (not shown). In this way, one can achieve and get a collection of flow sources in the net cage, which pushes the lice- free and oxygen rich water that is brought from the lower layers of water, into the net cage in the wanted direction and which in turn can be controlled, and which generates an injector effect in addition to the main flow itself out of the pipe outlets 34. It is appropriate to have a net or something similar on the outlet 34 to ensure that the fish do not swim into the pipe.

There is a collecting funnel 18 under the net 14 itself, which is conical and which, during the delousing in the net cage, can easily be lifted up via the vertical folds of the lice skirt 16 and meet the lower edge 16a of the skirt so that one has a closed unit, as shown in fig. 2.

In this way one does not need to carry out an expensive and extensive delousing which is normally required and according to the invention one saves the effort, at the same time as the risk of escapes and stress for the fish are eliminated. The collecting funnel 18 can be connected with the floating collar 12 via the skirt 16, or directly via rope or cables, and can be moved up and down in the net cage partly with the help of a buoyancy ring uppermost in the collecting collar and via a rope integrated in the skirt.

The collecting funnel 18 can be met in a centrally mounted sludge funnel 20, so that collected sludge, faeces, feed remains, etc. can be collected and be transported to the surface via a sludge pipe 22. In the embodiment example, three flow setters 30 are used. It is natural that fewer or more can be used than that shown. However, figure 5 shows an example of a set-up of the flow setters 30 where they are placed in the form of a triangle, preferably as an equilateral triangle so that the forces are taken up evenly. The struts 42 run as shown between the floating collars 40 of the respective flow setters 30, and furthermore, where said floating collars can be anchored to the floating collar 12 of the fish farm 10 via cables or rope 44. The flow setters 30 can then be placed in an outer periphery of the net 14, i.e. relatively near the net wall. Such a triangular solution of the flow setters and the intake of water so far out against the net wall as possible can lead to increased oxygen levels in the body of water that is brought up to the upper water layer. The oxygen supply can be rendered in that oxygen is injected into the flow setters 30, both upstream of the propeller 38 and/or downstream of the propeller, as one gets a fine oxygen supply and distribution of oxygen in the net cage in that the oxygen is dissolved in the fresh water coming from the nozzles in the outlet 34 without the fish being stressed due to the displacement, and at the same time as one saves much oxygen as the more stress the more oxygen is consumed. As the oxygen is expensive, this will in total be seen as a much less costly delousing than what is done today.

To obtain an even better environment for the fish in the upper water layer, oxygen can be injected at any location on the intake pipelines on the suction side or the pressure side of the flow setter on one or more inlet lines.

So that it will still possible to carry out a delousing, an embodiment example is shown in figure 10, a version with only a lice skirt and net in the fish farm 10. The flow setters 30 can be tilted and be pulled inwards in the strut frame and be fastened in an approximately horizontal position with the help of a drive motor 52 or a sliding cylinder. For that reason, the flow setters 30 can be mounted via a hinge 54 so that the suction pipe 36 can be lifted up to a position so that the bottom ring 24 of the net can be raised up as is the common practice in a tarpaulin delousing today.

The collecting funnel 18 makes it possible, according to the invention, to carry out a delousing without the use of external help, apart from raising the collecting funnel 18 and possibly lowering the skirt so that this lies against the skirt 16 and seals the net cage and the delousing can start from here and lice that are released from the fish can be collected in the collecting funnel 18 and be sucked up to a destruction unit that is not shown in the figures. Alternatively, the hemline 16a of the skirt can be lowered down to the collecting funnels 18. The oxygen supply can be provided by an external oxygen supply.

To raise the collecting funnel 18 and possibly the bottom ring 24, the floating collar 12 of the fish farm 10 can be comprised of equipment in the form of winches or the like.

In another embodiment, as shown in figure 6, the flow setter 30 is placed in the approximate centre of the net 14, with distribution of water out through one or more nozzle pipes 60 fastened to the suction pipe 36, possibly to respective outlets 34, which are preferably directed outwards at an angle which created a flow that in turn leads to an environment rich in oxygen and free of lice in the net cage. The flow setter 30 can, via cables or rope 44, be anchored to the floating collar 12 of the fish farm 10. In the embodiment shown, three nozzle pipes 60 are placed in the suction pipe 36, where the nozzle pipes are placed at a mutual and preferably equal distance apart circumferentially. The nozzle pipes 60 shown can also be used in the solution described and shown in the other figures.

Figure 3 shows a further embodiment of the fish farm 10 according to the invention. In addition to other mentioned construction features, it can comprise an extra net 28 placed externally to the first net 14. The additional net 28 can be fastened to the skirt 16, for example, to the hemline 16a, and stretch down to the bottom ring 24.

Alternatively, the additional skirt can be fastened to the floating collar 12 of the fish farm 10 and correspondingly extend down to the bottom ring 24. The additional net 28 can be formed correspondingly as a standard net or a net formed as a plankton canvas, i.e. a fine-meshed canvas, so that lice are not let through and into the fish farm 10. Because of the size of the fish farms, there will still be sufficient water throughflow into the net14 even if the additional canvas is very fine meshed. Also, to prevent inflow of lice, the additional canvas will also result in a double wall which can prevent escapes if holes arise in the net 14.

As shown in figure 4, the flow setters 30, or preferably the floating collars 40 of the flow setters, can be equipped with an upper stand 56 that supports a bird's net 58

Claims

CLAIMS.

1. Fish farm (10) for farming of fish, comprising: a floating collar (12) that floats in the water surface, a net (14) fastened to the floating collar (12) to hold the fish to be farmed, where the net (14) is also fastened to a bottom ring (24) down in the water, and also a skirt (16) that surrounds the net (14) and which extends down into the water to an area above the bottom ring (24), characterised in that

several tiltable flow setters (30) equipped with a floating collar (40) are placed rigidly connected with each other and standing inside the net (14), where respective flow setter (30) comprises an elongated, vertical suction pipe (36) with a lower inlet (32) placed in an area below a lower hemline (16a) of the skirt (16), for suction of water, and an upper mainly horizontal outlet (34) to distribute the water in an upper body of water of the net (14) and to set the upper body of water in rotation.

2. Fish farm according to claim 1, characterised in that the outlet (34) is placed below the water surface (26) of the upper body of water.

3. Fish farm according to claim 1, characterised in that the inlet (32) of the flow setters (30) is placed in an area adjoining the bottom ring (24).

4. Fish farm according to claim 1, characterised in that said floating collars (40) of the respective flow setters (30) are connected to each other by struts (42) to provide a rigid construction to take up forces that come from the outlet (34).

5. Fish farm according to claim 4, characterised in that the floating collars (40) of the flow setters (30), and/or any struts (42) are anchored to the floating collar (12) of the fish farm.

6. Fish farm according to claim 1, characterised in that three flow setters (30) are mounted in the fish farm, so that their placing constitutes an equilateral triangle.

7. Fish farm according to claim 1, characterised in that the outlet (34) is rotatable mounted to the suction pipe (36).

8. Fish farm according to claim 1, characterised in that the floating collar (40) of respective flow setters (30) is articulately connected with the struts (42) and that a motor (52) is mounted to the floating collar (40) to tilt and pull the flow setters (30) into a mainly horizontal position.

9. Fish farm according to claim 1, characterised in that underneath the net (14) or in the area underneath the bottom ring (24), a collecting funnel (18) is arranged that runs down in the water and which is met in a central sludge funnel (20) from which a sludge pipe (22) runs up to the floating collar (12).

10. Fish farm according to claim 1, characterised in that the outlet (34) of the flow setter (30) is equipped with one or more nozzle pipes (60).

11. Fish farm according to claim 1, characterised in that an extra net or canvas (28) is arranged outside the net (14) which contains the fish that shall be farmed and through which the lice cannot penetrate, as the extra net (28) is suspended in the skirt (16) or in the floating collar (12).

12. Net cage according to claim 1, characterised in that the flow setters (30) comprises equipment for supply of oxygen by the injection of oxygen into the suction pipe (36).

13. Method for delousing in a net cage (10) for farming of fish, where the net cage (10) comprises: a floating collar (12) that floats on the surface of the water, a net (14) fastened to the floating collar (12) to contain the fish that shall be farmed, where the net (14) is also fastened to a bottom ring (24) down in the water, a skirt (16) that surrounds the net (14) and which stretches down into the water to an area above the bottom ring (24), and a collecting funnel (18) suspended underneath the net (14) or the bottom ring (24), and also that the net cage (10) comprises a number of vertically arranged flow setters (30) in the net (14) , c h a r a c t e r i s e d in that said flow setters (30) are tilted and pulled up during raising of the collecting funnel (18), and

raising of the collecting funnel (18) and the bottom ring (24) up to a hemline (16a) of the skirt (16) to seal the net cage (10), followed by delousing in a normal, known way.

14. Method according to claim 13, characterised in that during raising of the collecting funnel the hemline (16a) is lowered until the skirt meets the collecting funnel (18).

15. Method according to claim 13, characterised in that lice removed from the fish are collected in the collecting funnel (18) and are sucked up to a destruction unit.