WO2011074982A1

WO2011074982A1 - System and method for treating fish

Info

Publication number: WO2011074982A1
Application number: PCT/NO2010/000460
Authority: WO
Inventors: Steinar Gjersdal
Original assignee: Ocean Solutions As
Priority date: 2009-12-14
Filing date: 2010-12-14
Publication date: 2011-06-23
Also published as: GB2491500A; GB201212490D0; CL2012001607A1; NO20120807A1

Abstract

A system (5, 10, 300, 310) for treating biomass includes a tarpaulin arrangement (10) fluidly coupled via a configuration of fluid-guiding pipes to control apparatus (300). Moreover, the tarpaulin arrangement (10) is adapted to be deployed and to enclose a net, enclosure or cage (80), and the tarpaulin arrangement (10) is provided with a plurality of floats (20, 30, 40, 50, 60, 70) disposed thereon so that selective adjustment of buoyancies of the floats (20, 30, 40, 50, 60) enables the tarpaulin arrangement (10) to adjust a volume of water present within the net, enclosure or cage (80) during treatment of the biomass. The biomass is optionally salmon fish, and the treatment if optionally de-licing of the salmon fish.

Description

SYSTEM AND METHOD FOR TREATING FISH Technical field of invention

The present invention relates to systems for treating aquatic biomass, for example to systems for treating fish such as salmon which are infested with parasites such as lice. Moreover, the present invention concerns methods of treating fish, for example methods of treating fish which are invested with lice and other types of parasitic aquatic organisms.

Background to the invention

Contemporary therapeutic bathing methods for treating fish which are infested with lice are known. These lice are, for example, of a type salmon lice Lepeoptheirus salmonis and Scottish lice Caligus elongatus. The bathing methods utilize closed, or entirely covered, tarpaulin arrangements ( "bathing tarpaulins") which are drawn into position adjacent to fish cultivation enclosures or cages by firstly sinking the tarpaulin arrangements under the enclosures or cages, and thereafter unfolding and drawing them up into position under the enclosures or cages by way of mechanical apparatus such as cranes, winches and similar. The tarpaulin arrangements are held up at a water surface position by way of air-filled elongate floats which are attached to upper surfaces of the tarpaulin arrangements which have substantially circular peripheral edges; the elongate floats are filled with a sufficient volume of air to provide required buoyancy.

In aforementioned tarpaulin arrangements, there are also utilized one or more "skirts", namely the tarpaulin arrangements have bottom regions which, in operation, are installed around fish enclosures or cages. However, such contemporary tarpaulin arrangements and associated methods of utilization are not especially effective on account of dilution and diffusion of therapeutic materials employed therein treat fish within associated enclosures or cages. When the tarpaulin arrangement has been drawn into position around an enclosure of cage, and encloses the enclosure or cage entirely from its bottom portion to its surface portion, a therapeutic agent for removal of parasites such as lice from fish included with the enclosure or cage is added at a surface of a treatment volume of water enclosed within the tarpaulin arrangement. The therapeutic agent is optionally assisted by an addition of Oxygen which is provided from oxygenation grids or an oxygenating apparatus which is included within the enclosure or cage.

When treatment has been administered to fish within the enclosures or cages, air is released from the aforesaid elongate air-filled floats; inking arrangements, for example weights, attached to the tarpaulin arrangement cause the tarpaulin arrangement to sink simultaneously with further air being pressed out of the elongate floats. Eventually, the tarpaulin arrangement is removed in an at least partially submerged state away from the enclosure or cage. Unfolding and positioning of the tarpaulin arrangement under the enclosure or cage takes place before it is lifted using the air-filled floats to the surface; the tarpaulin arrangement is usually disposed at sea from, for example, a boat, whereafter the tarpaulin arrangement is then sunk down into a mass of water of a sea environment accommodating the enclosure or cage. The tarpaulin arrangement is conventionally drawn under the cage and enclosure, amongst other with assistance of weights and side tows, wherein these are used to draw the tarpaulin arrangement to a most unfolded position under the cage or enclosure before air is pumped into the aforesaid elongate floats. According to earlier literature, up to six to seven personnel are needed for implementing manipulation and deployment of the tarpaulin arrangement. Additionally, considerable forces are utilized from assistance boats, and cranes and/or winches for deploying and unfolding the tarpaulin arrangement; such a manner of operation potentially results in wear, tears and holes and ripped-off attachments from the tarpaulin arrangements.

Contemporary methods of treating fish thus provide little possibility for a controlled "self unfolding and deployment" (self-deployment) of the tarpaulin arrangement in a submerged state and prior to it being raised to a surface position, or to maintain the volume of water within the tarpaulin arrangement washed out under the entire treatment, together with providing a controlled tarpaulin arrangement spatial form and a controlled degree of filling in the treatment volume included within the tarpaulin arrangement.

It is usual when employing contemporary known tarpaulin arrangements to undertake a raising of a bottom ring and a realignment of walls of the cage or enclosure, together with the enclosure or cage pointed end, namely bottom section, being raised towards and eventually ' to the water surface remote from a region where treatment has been provided.

Contemporary methods of treating fish do not provide a possibility for controlled regulation of the treatment volume's extent by controlling incoming and exiting water streams in connection with a continuous washing out of a volume of water included within the tarpaulin arrangement in association with administering treatment, namely something which is an important compliance in connection with a total biomass which is to be treated at any given time. Moreover, contemporary methods do not provide for controlled and rapid suction or evacuation of gas and/or liquid from a cultivation system by use of vacuum pumps and/or vacuum compressors in connection with rapid and controlled sinking of the tarpaulin arrangement after completed treatment. A lack of possibilities for controlled water volume determination and regulation of a treatment volume can result in an unnecessarily large use of medication, namely on account of unsatisfactorily low fish volume concentration or biomass concentration in an involuntary treatment volume of water. Such a situation can also result in there being overdosing of medication which can be fatal, can cause stress or damage fish, for example salmon, or there can arise an under dosing which results in development of resistance of parasites to medication, for example salmon lice develop resistance to medication, namely something which has contemporarily become a major financial problem in salmon industries.

On account of walls of the tarpaulin arrangement and its bottom in contemporary systems not being held fully outwardly deployed during treatment, there results thereby that the tarpaulin arrangement can potentially assume a variable spatial form, for example on account of naturally and varying water streams and water stream directions, tidal streams and similar acting upon an outside surface of the tarpaulin arrangement; for example, the tarpaulin arrangement can become funnel-shaped, namely something which can render more difficult constant and controlled oxygenating in the treatment volume as well as which can render it difficult to observe fish during treatment. Problems such as layering or uneven distribution when applying medication in a treatment volume of water can arise, with a consequence that fish attempt to avoid treatment or medication when possible.

Contemporary systems for treatment of fish in general are only adapted for administering treatment in a circular or round cultivation enclosure or cage, and not for rectangular or multi-sided enclosures or cages.

It will thus be appreciated that contemporary tarpaulin arrangements, for use with enclosures or cages for cultivating fish, for administering treatment to the fish have many problems which the present invention seeks to address .

Summary of the invention

The present invention seeks to provide an improved tarpaulin arrangement for use with fish cultivation enclosures and cages .

The present invention seeks to provide an improved treatment system for aquaculture, for example to fish aquaculture.

The present invention seeks to provide improved methods of administering treatment to aquatic biomass included within enclosure or cages .

According to a first aspect of the present invention, there is provided a system for treating biomass, wherein the system includes a tarpaulin arrangement fluidly coupled via a configuration of fluid-guiding pipes to control apparatus, characterized in that the tarpaulin arrangement is adapted to be deployed and to enclose a net, enclosure or cage, and the tarpaulin arrangement is provided with a plurality of pressure snake or floats disposed thereon so that:

a) selectively pressurizing of the snakes or floats by liquid with desired pressure, so that they are pressurized to their maximum spatial size so that the tarpaulin gets distended e.g. generally flat horizontally;

b) lowering the tarpaulin to a suitable depth below the net, enclosure or cage, simplifying the task of deploying the tarpaulin underneath the net, enclosure or cage; and c) selectively adjusting buoyancies of the pressure snakes or floats in the tarpaulin arrangement, so that a volume of water present within the net, enclosure or cage during treatment of the biomass can be controlled.

The system is of advantage in that effective enclosure of the net, enclosure or cage and also control of a volume of water therein for rendering applied treatment of the biomass more effectively.

Optionally, the system is implemented so that the floats are disposed in operation in one or more annular formations whose buoyancies are mutually independently controllable. Optionally, the system is implemented so that one or more side portions of the tarpaulin arrangement are provided with one or more valves or controllable apertures for selective introduction or expelling of water from a volume enclosed in operation by the tarpaulin arrangement.

Optionally, the system is implemented so that the tarpaulin arrangement and its associated floats are adapted, in a collapse deflated state, to be wound onto a drum for transport away from the net, enclosure or cage.

Optionally, the system is implemented so that the tarpaulin arrangement includes a frusto-conical portion therein when in a deployed state.

Optionally, the system is implemented so that the tarpaulin arrangement is of a generally tapered form when in a deployed state.

Optionally, the system is implemented so that the tarpaulin arrangement includes visual markers on its sides for use in determining upon visual inspection a volume of water included within the tarpaulin arrangement.

Optionally, the system is implemented so that the tarpaulin arrangement is provided with an arrangement for oxygenation for oxygenating biomass and/or an arrangement for addition of bathing agents included in operation within the tarpaulin arrangement .

Optionally, the system is implemented so that the tarpaulin arrangement and its associated floats are fabricated from one or more flexible plastics materials.

More optionally, the system is adapted for de-licing salmon.

According to a second aspect of the present invention, there is provided a method of treating biomass within a net, enclosure and cage, wherein said method includes steps of:

(a) distending and deploying a tarpaulin arrangement around the net, enclosure and cage; (b) increasing buoyancy of one or more floats for dispelling a volume of water from the tarpaulin arrangement and thereby from the net, enclosure and cage;

(c) applying a process to the biomass included within the net, enclosure and cage whose associated volume of water has been reduced in step (b) .

Optionally the method involves subjecting the volume of water within the tarpaulin arrangement to forced oxygenation and/or for adding bathing agents .

Features of the invention are susceptible to being combined on various combinations . Description of the diagrams

Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:

FIG. 1 is an illustration of a biomass aquaculture enclosure or cage within an aquatic environment and with a lower frusto-conical base portion, wherein the enclosure or cage is surrounded by a tarpaulin arrangement pursuant to the present invention, and wherein the tarpaulin arrangement is supported by ropes integrated with flotes, particularly when being deployed;

FIG. 2 is an illustration of a biomass aquaculture enclosure or cage within an aquatic environment, wherein the enclosure or cage is surrounded by a tarpaulin arrangement pursuant to the present invention, and wherein the tarpaulin arrangement has a frusto-conical general spatial form when in use; FIG. 3 is an illustration of a tarpaulin arrangement of substantially a type as illustrated in FIG.1 or FIG. 2, wherein the tarpaulin arrangement has been at least partially raised to a water surface to reduce a volume of water including an associated aquaculture enclosure or cage;

FIG. 4 is an illustration of a generally conical tarpaulin arrangement including multiple circumferential pressurized snake-shape floats for controlling the tarpaulin arrangement within an aquatic environment;

FIG. 5 is an illustration of the tarpaulin arrangement as illustrated in FIG. 4, with input and output pipes, as well as netting included at a lower portion of the tarpaulin arrangement; and

FIG. 6 is a general illustration of the tarpaulin arrangement 10 surrounding an aquaculture cage or enclosure 80, wherein the tarpaulin arrangement 10 is coupled via various pipes to apparatus for injecting air, fluid or underpressure into various portions of the tarpaulin arrangement 10 and its associated floats.

In the accompanying diagrams, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

Description of embodiments of the invention

As will be described now in greater detail, the present invention is concerned with systems and methods for improved and controllable therapeutic treatments for aquatic organisms; for example, the present invention is concerned with salmon as aquatic organisms, and with methods of de-licing such salmon in a closed aquatic treatment system, for example indicated generally by 5 in FIG. 1. The system is beneficially implemented using a tarpaulin arrangement, for example constructed using plastics material sheets and similar types of water-tight material adapted for aquaculture. Moreover, the tarpaulin arrangement is beneficially adapted for use with enclosures or cages, wherein the enclosures or cages can be round or multi-sided. The present invention also concerns methods of controlled deployment and application of the tarpaulin arrangement, together with methods of water quantity regulation of a treatment volume of water including control and rapid sinking of the tarpaulin arrangement during use.

The present invention addresses, amongst other problems, aforementioned limitations experienced with known contemporary fish treatment systems as well as providing improved treatment methods in a range of areas by equipping a treatment unit and associated tarpaulin arrangement 10 with associated control arrangements which will now be described in more detail.

Embodiments of the invention will now be described in greater detail with reference to FIG. 1 to FIG. 6. In these diagrams, a system is denoted by 5, a tarpaulin arrangement is denoted by 10, flexible pressurizable elongate floats (also called "pressurized snakes") are denoted by 20 to 60, vertical ropes with floats are denoted 70, and a floating enclosure or cage for aquaculture is denoted by 80. The enclosure or cage 80 is, for example, operable to include fish such as salmon which is nurtured for eventual slaughter and subsequent human consumption. A central portion of the enclosure or cage 80 is denoted by 130. Elongate air floats are denoted by 140, 150. A bottom end of the tarpaulin arrangement 10 is denoted by 100 and optionally has a arrangement for towing associated therewith. Optional input and output pipes 170 are attached to the cage or enclosure 10 for enabling controlled input and output of water from a volume included within the cage or enclosure 80. The tarpaulin arrangement 10 and its associated floats are beneficially fabricated from one or more plastics materials, for example reinforced polyvinyl chloride (PVC) polymer, reinforced polyurethane, reinforced polyethylene polymer. Beneficially, such reinforcement is achieved using polyester fibres, Nylon fibres, Dyneema fibres, carbon fibres which are beneficially in an interwoven formation. A top edge or top rim of an appropriately selected tarpaulin arrangement 10 defines a surface area of a treatment volume of water. Beneficially, outside walls of the tarpaulin arrangement 10 and a bottom section of the tarpaulin arrangement 10 are equipped in an appropriate manner with an arbitrary number of flexible annular "pressure snakes" 20, 30, 40, 50, 60 which are susceptible to being folded together when in a deflated state. The tarpaulin arrangement 10 is generally substantially impervious to flow of water directly therethrough. The pressure snakes 20, 30, 40, 50, 60 are beneficially implemented as elongate air- filled floats which are arranged as annular structures. The pressure snakes 20, 30, 40, 50, 60 are beneficially deployed in a horizontal orientation as illustrated with appropriate extent and diameter and in suitable arbitrary and desired distance from one another, namely from top to bottom in the tarpaulin arrangement 10 which is operable to function as a treatment unit. For example, the tarpaulin arrangement 10 is beneficially implemented with thee pressure snakes 40, 50, 60 at a bottom region thereof and two pressure snakes 20, 30 at sides of the tarpaulin arrangement 10 in addition to pressure snakes which are always attached to an upper surface or top edge of the tarpaulin arrangement. These pressure snakes 20, 30, 40, 50, 60 are designed to withstand fluid pressure of gas and/or liquid, together with controlled application of reduced pressure ("underpressure") or even vacuum.

There is further coupled, in addition to the pressure snakes 20, 30, 40, 50, 60, one or more relatively thinner input or output pipes 170 of suitable length, dimension and strength and which are adapted for being pressurized by liquid with desired pressure, for example sea water, or gas with desired pressure, for example air, or a mixture of water and gas with desired pressure. The pressure 170 are pressurized in operation and are strongly deployed to their maximum spatial size, namely diameter and extent, depending upon pressure applied thereto. An arbitrary mixture of liquid and gas beneficially provides a self-buoyancy effect of the treatment unit implemented using the tarpaulin arrangement 10 when in a sunken state in connection with deployment in addition to a desired cleansing effect for fish maintained within the enclosure or case 80. The pressure snakes 20, 30, 40, 50, 60 are also subjected during operation to a controlled underpressure or vacuum via associated input and output pipes, wherein the pressure snakes 20, 30, 40, 50, 60 are operable to lose their internal volume and "collapse", and wherein the entire treatment unit including its pressure snakes 20, 30, 40, 50, 60 can be rolled together, for example onto a drum, after use, and in connection with eventual disinfection of the tarpaulin arrangement 10. Supply and removal of fluids in addition to execution of work operations are beneficially implemented from a working boat 310, floats and similar which are equipped with necessary apparatus 300 such as water pumps, air compressors and vacuum compressors.

The horizontally disposed pressure snakes 20, 30, 40, 50, 60, which are attached to the tarpaulin arrangement 10 as illustrated, beneficially are of a strength and a quality which are adapted to withstand a maximum fluid pressure which is required for achieving a cleansing effect, and a spatial extent which is suitable for a size, a form and a placement of the cage or enclosure 80. The pressure hoses optionally have mutually different sizes, diameter and so forth, and are adapted for different uses and functions for achieving a desire cleansing effect and buoyancy effect on the tarpaulin arrangement 10.

The pressure snakes 20, 30, 40, 50, 60 are optionally subdivided along their length into several sections, for example sections 140, 150, in an arbitrary number of sections for mounting of skirt pieces, for example plastics materials pipes or adapted bends, which are equipped with watertight bulkheads; beneficially, each section 140, 150 can be subjected individually to pressure by liquid and/or gas, or be subjected to a controlled underpressure or vacuum. Moreover, the sections 140, 150 are beneficially implemented so that they can be individually selectively pressurized with fluid, namely liquid and/or gas, or can be subjected to a controlled underpressure or vacuum. Functioning of each section 140, 150 is beneficially controllable in a mutually independent manner, namely so that certain sections can be buoyant to provide buoyancy lift, for example can be placed under excess pressure, whereas other sections 140, 150 can be sunk and are at the same time are subjected to water pressure or vacuum under-pressure . Beneficially, there is employed at least one skirt with a sealed bulkhead or manifold for supply of fluid to each pressure snake, depending upon desired function of each pressure snake.

The tarpaulin arrangement 10 is optionally further equipped with one or more suitable openings which, for example, can be deployed around a centre at a water surface, for example as in FIG. 3, or a centre at a bottom region of the tarpaulin arrangement 10, see FIG. 4 and FIG. 5, or even on sides, for example input and output pipes 170, of the tarpaulin arrangement 10 for controlled regulation of input and output water volumes, and for controlled water injection into a treatment volume within the tarpaulin arrangement 10, as well as water processing such as filtration and oxygenation within a closed circuit, namely for recirculating water. Optionally, openings in the tarpaulin arrangement 10 have mutually different form and size depending upon operating requirements; optionally, the openings are equipped with valves, for example by way of a Venetian blind type of configuration with multiple louvers or flaps, beneficially disposed on a inside surface of the tarpaulin arrangement 10 which can be opened and closed depending upon operating requirements. For example, by using a controllable air- filled elongate float, namely an "air sausage" float, louvers or flaps of such valves can be raised by injection of gas into the float, thereby enabling water flow to pass therethrough. Moreover, closure of such valves is beneficially achieved by causing them to lie close to the tarpaulin arrangement 10, wherein in gas is removed from the aforementioned "air sausage" float, at the same time that the louvers or flaps are "automatically" thereby pressed down to establish an excess pressure on an inside of the tarpaulin arrangement 10. Other types of valve solution are optionally employed, for example inflatable annular rings, sliding baffles and similar. In an event that an opening, namely aperture, is established in a bottom region of the tarpaulin arrangement 10, for example as illustrated in FIG. 4 an FIG .5, netting 160 is beneficially employed for reducing opposing forces or water forces when the tarpaulin arrangement 10 is being hoisted up or sunk so that water can flow through openings in the tarpaulin arrangement 10 and through the netting 160. Additionally, the tarpaulin arrangement 10 is optionally provided with a necessary amount of sinking medium, for example weights, sinking chains and similar, such that the tarpaulin arrangement 10 effectively sinks when a gas volume associated therewith is evacuated from its pressure snakes at a same time that one or more of the pressure snakes 20, 30, 40, 50, 60 are filled with liquid, for example sea water.

As illustrated in FIG. 1 to FIG. 5, the tarpaulin arrangement 10, in certain example circumstances, is provided with a sausage-shaped float which is beneficially disposed at a bottom of the tarpaulin arrangement 10 when in a deployed state; for example, the coupled float is beneficially of suitable size and quality which can be manoeuvred up to a surface of water surrounding the tarpaulin arrangement 10 for controlled removal by suction of treatment water for removal of waste therefrom, for example filtration of dead and living salmon lice, parasite eggs and strings of eggs in connection with a bottom region of the tarpaulin arrangement 10 being sunk downward at an end of treatment of fish or other biomass present within the enclosure or cage 80.

Additionally, oxygen or aeration pipes, snakes or the like are beneficially integrated onto an inside of the tarpaulin arrangement 10 for controlled supply of oxygen or other bathing agents to a treatment volume of water included within the arrangement 10 during treatment of fish and/or biomass within the enclosure or cage 80. Such a manner of oxygenation and addition of bathing agents^' avoids a need for apparatus to be included within the tarpaulin arrangement 10, namely oxygenation and bathing agent equipment for use with the aeration pipe or snakes can be mounted remotely from the tarpaulin arrangement 10. Optionally, the tarpaulin arrangement 10 is provided with visual "volume markers" which are beneficially employed on an inside of the tarpaulin arrangement 10, at a bottom region thereof, for providing visual information regarding a volume of water present within the tarpaulin arrangement 10, for example for assisting with dosing of medication. The "volume markers" are beneficially visible to human inspection when the tarpaulin arrangement 10 is deployed at a surface of the water.

There are then several variations in which the present invention is susceptible to being executed. One possible sequence of operation is listed below. In addition, some of these steps may also preferably be executed in another order than indicated. Some steps may also be repeated depending on the progress of the treatment.

A first step (STEP 1) involves the tarpaulin arrangement 10 being set out to sea, for example by being towed by a boat 310 or being dragged via a drum and rope or similar; the tarpaulin arrangement 10 is then sunk down so that it hangs freely with its associated binding ropes with floats 70 so as to be suspended at the surface region. A second step (STEP 2) involves inputting sea water via one or more input hoses or conduits so that the tarpaulin arrangement 10 is distended to its maximum size, namely maximum depth and diameter. The tarpaulin arrangement 10 is now gets extended generally flat horizontally.

A third step (STEP 3) involves moving the tarpaulin arrangement 10 under the enclosure or cage 80, for example by using towing rope which are attached to the vertically standing ropes with floats 70, simultaneously whilst oxygenation is applied by using an integrated oxygen snake or oxygen emitter which is attached to an inside of the tarpaulin arrangement 10; such an arrangement ensures that a sufficient oxygenation occurs so that fishes, for example within the enclosure or cage 80 maintained within the tarpaulin arrangement 10, when the fishes are brought to the surface for treatment, for example de-licing.

At the third step (STEP 3), there are then several alternative manners in which the present invention is susceptible to being executed; a treatment volume of the tarpaulin arrangement 10 is then subject to a "donut" or "ice-cake" adjustment, namely that the fish are treated in an established ring-shaped volume outwardly to sides of the enclosure or cage 80, and not in a central portion thereof. There are thereby beneficially observation opportunities for inspecting the fishes, for example as illustrated in FIG. 1, FIG. 2 and FIG. 3, from a walkway or platform disposed around a surface peripheral edge of the tarpaulin arrangement 10. Moreover, there is also provided more controlled water streaming measurements and oxygen measurement, in addition to controlled additions of bathing agents without risk of causing contamination or mess. A fourth step (STEP 4) involves, when the tarpaulin arrangement 10 is moved into position under the enclosure or cage 80, addition of pressurized gas, for example compressed air or oxygen, is applied to an upper pressurized snake at a top of the tarpaulin arrangement 10, whereat the gas displaced liquid therein; beneficially, liquid is also expelled from supply hoses. Application of pressurized air results in the tarpaulin arrangement 10 being held open at a surface position.

A fifth step (STEP 5) involves applying pressurized air into a lowest pressure snake nearest to a centre bottom of the tarpaulin arrangement 10, which results in a pressure snake nearest the centre being heaved to a surface position with a tip of netting of the enclosure or cage 80 being at a centre, simultaneously with water being forced out through holes or apertures in the tarpaulin arrangement 10.

A sixth step (STEP 6) involves, in an event that it found that a volume enclosed by the tarpaulin arrangement 10 is larger than a desired size, there is injected pressurized air to a next lower pressure snake relative to a bottom of the tarpaulin arrangement 10 at a same time that a controlled vacuum or underpressure is applied to a lowest pressure snake. In this manner, the next lower pressure snake is operable to lift the centre of the tarpaulin arrangement 10 to a surface position, simultaneously with sea water being pressed out through openings, apertures of valves in a central bottom region or in sides of the tarpaulin arrangement 10. When the next lower pressure snake has risen to a surface position, further water is now pressed out of a hole in a middle section of the tarpaulin arrangement 10 or at sides of the tarpaulin arrangement 10. A seventh step (STEP 7) involves, in a situation that the tarpaulin arrangement 10 is still larger than a desired enclosure of cage 80 volume, placing the third lower pressure snake under pressure by injecting air thereinto, simultaneously with a vacuum or underpressure being applied to the next lower pressure snake such that sea water is pressed out of an opening in a mid-section or from sides of the tarpaulin arrangement 10, and by such an approach a reduction in volume within the tarpaulin arrangement 10 occurs by using various judiciously position pressure snakes, until a desired volume of water within the tarpaulin arrangement 10 is achieved in relation to netting volume.

An eighth step (STEP 8) involves applying a treatment material in appropriate dosage adapted to the established volume within the tarpaulin arrangement 10 volume, wherein an exact treatment volume amongst others can be computed based on depth measurements and/or a known cross-sectional profile of the treatment volume and/or based upon which pressure snake in the bottom section of the tarpaulin arrangement 10 which is found in a surface position and is pressurized with gas. A determination of an exact treatment volume pursuant to the present invention can also be achieved by using "volume markers" in the tarpaulin arrangement 10, wherein the volume markers are beneficial to provide exact tarpaulin volume when the volume markers become visible above the water surface.

A ninth step (STEP 9) is concerned with a situation during treatment where there arises a need to employ a controlled increased volume of the tarpaulin arrangement 10 or its associated netting volume, or rapidly introduce new water from outside the tarpaulin arrangement 10; such control is beneficially achieved by applying a vacuum or an underpressure to a pressure snake at a centre of the tarpaulin arrangement 10 which is found at the surface; such vacuum or underpressure causes a middle section of the tarpaulin arrangement 10 to sink with a result that water then streams in through opening in a bottom section of the tarpaulin arrangement 10 or through sides of the tarpaulin arrangement 10 until one of the next pressure snakes is under pressure and rises to a surface position, and thereby access to water from outside the tarpaulin arrangement 10 is halted.

In an event that it is desirable, for example, to oblige the fish to move to a greater extent, at an end of a handling period, to achieve more movement between the fish and the lice, with a consequence of detachment of lice, this can be achieved by causing a reduction of water in the aforementioned volume created within the tarpaulin arrangement 10.

An tenth step (STEP 10) is concerned with an optional to what extent the mid-section or extremities of the tarpaulin arrangement 10 are sunken first or last by applying water at pressure which gradually replaces gas or applies a controlled vacuum or underpressure in pressure snakes 20, 30, 40, 50, 60 for evacuation of both gas and liquid therefrom. The tarpaulin arrangement 10 can also be sunken in a deployed state, by pressurizing all the pressure snakes 20, 30, 40, 50, 60 with liquid, and in this manner the treatment is applied simultaneously in other tarpaulin arrangements from boats 310 or floats, namely a manner of operation which saves time and resources .

After completion of treatment, and after the tarpaulin arrangement 10 is sunken to a greater extent, the tarpaulin arrangement 10 is then submitted to the same state as in STEP 3 above. The tarpaulin arrangement 10 eventually also hangs with vertically standing ropes with floats 70. Then the tarpaulin arrangement 10 is moved away like but opposite to in STEP 3. A vacuum or underpressure is optionally applied to all the pressure snakes for removing all gas and/or liquid in connection with eventual uptake of the tarpaulin arrangement 10 onto a drum. All gas and/or liquid used during the deployment and use of the tarpaulin arrangement 10 may preferably be disinfected, re-circulated, reused or otherwise taken care of. Particularly seawater used in the pressure snakes or floats (20,30,40,50,60,70) may be purified and stored in tanks 300 for reuse in order not to contaminate the environment. This is not the least important if the equipment is moved and used different places.

Alternative uses of the invention include, for example, controlled deployment of the tarpaulin arrangement 10 to a surface position as described in the foregoing so as a form of containment skirt, for example beneficially to position pressure snakes in horizontal and arbitrary distance from the skirt . In a situation wherein four pieces of skirting are employed in mutually 90° disposition, it is beneficial to utilize joins in pressurized snakes of the tarpaulin arrangement's 10 in order to construct a four-sided handling unit adapted for use with four-side enclosures or cages 80 employed in fish cultivation. In a situation where one of the four sections is filled with air under pressure, the other three sections are filled with water, it is easy to introduce the tarpaulin arrangement 10, namely treatment unit, to enclosures and cages 80 for achieving a rapid deployment of the tarpaulin arrangement 10 under netting of the cage or enclosure 80; subsequently, air is pumped in the other three of the four sections and the tarpaulin arrangement 10 which is then thereby lifted to a surface position, and treatment process for fish is then implemented as described in the foregoing STEP 1 to STEP 10.

Aforementioned equipment for the tarpaulin arrangement 10 together with utilization thereof is beneficially implemented pursuant to laws and regulations of countries where the present invention is utilized.

In conclusion, as described in the foregoing, the invention enables -therapeutic processes to be applied to fish of all types housed within floating aquaculture apparatus; the invention provides for a more rapid, easier and more controlled application of the processes. Apparatus pursuant to the present invention utilizes mutually coupled pressure snakes, optionally with skirt-like components, which are adapted in a tarpaulin arrangement 10 which is operable changeably by independent application of pressure with liquid and/or gas, or by application of a controlled vacuum or underpressure, to achieve following benefits: a rapid distension of the tarpaulin arrangement 10 is achievable in a submerged state;

a rapid controlled regulation of a volume of water within the tarpaulin arrangement 10 and also a spatial form of the tarpaulin arrangement 10 is achievable when the arrangement 10 is at a surface position; controlled regulation of a water volume within the arrangement 10 is thereby adapted to an amount of biomass which is to be treated, thereby reducing a "dead volume" and give reduced use of medication with a corresponding environmental benefit;

(c) a rapid controlled exchange of water in the tarpaulin arrangement 10 during treatment operations is achievable via one or more openings by controlled raising and lowering of a bottom section of the tarpaulin arrangement 10;

(d) controlled oxygenation and/or filtering and/or recirculation of a volume of water within a closed circuit associated with the tarpaulin arrangement 10 is feasible;

(e) a rapid controlled sinking of the tarpaulin arrangement 10 after completed treatment of fish, also in rinsed state, is achieved by applying pressurized liquid and/or vacuum and/or underpressure to pressure snakes of the tarpaulin arrangement 10; and

(f) a rapid controlled de-licing is achievable within the closed tarpaulin arrangement 10, in a manner which is less labour-intensive and which requires fewer resources in comparison to known contemporary methods .

Although use of the system 5 is described in the foregoing in relation to, for example, salmon, the system 5 is capable of being used with other types of biomass, for example bioengineered plants for pharmaceutical product manufacture; for example, such plants need to be cleaned and purged of parasites on an occasional basis.

Modifications to embodiments of the invention described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "consisting of", "have", "is" used to describe and claim the present invention are intended to be construed in a nonexclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural . Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.

Claims

1. A system (5, 10, 300, 310) for treating biomass, wherein the system (10, 300, 310) includes a tarpaulin arrangement

(10) fluidly coupled via a configuration of fluid-guiding pipes to control apparatus (300) , characterized in that the tarpaulin arrangement (10) is adapted to enclose a net, enclosure or cage (80) , and the tarpaulin arrangement (10) is provided with a plurality of floats (20, 30, 40, 50, 60, 70) disposed thereon so that if:

a) selectively pressurizing of the floats (20, 30, 40, 50, 60) by fluid with desired pressure, so that they are pressurized to their maximum spatial size, the tarpaulin arrangement (10) gets distended e.g. generally flat horizontally; and

b) selectively adjusting buoyancies of the floats (20, 30, 40, 50, 60) in the tarpaulin arrangement (10) , a volume of water present within the net, enclosure or cage (80) during treatment of the biomass can be controlled.

2. A system (5, 10, 300, 310) as claimed in claim 1, wherein the floats (20, 30, 40, 50, 60) are disposed in operation in one or more annular formations whose buoyancies are mutually independently controllable.

3. A system (5, 10, 300, 310) as claimed in claim 1, wherein one or more side portions of the tarpaulin arrangement (10) are provided with one or more valves or controllable apertures for selective introduction or expelling of water from a volume enclosed in operation by the tarpaulin arrangement (10) .

4. A system (5, 10, 300, 310) as claimed in claim 1, wherein the tarpaulin arrangement (10) and its associated floats (20, 30, 40, 50, 60, 70) are adapted, in a collapse deflated state, to be wound onto a drum for transport away from the net, enclosure or cage (80) .

5. A system (5, 10, 300, 310) as claimed in claim 1, wherein the tarpaulin arrangement (10) is of a generally tapered form when in a deployed state.

6. A system (5, 10, 300, 310) as claimed in claim 1, wherein the tarpaulin arrangement (10) includes visual markers on its sides for use in determining upon visual inspection a volume of water included within the tarpaulin arrangement (10) .

7. A system (5, 10, 300, 310) as claimed in claim 1, wherein the tarpaulin arrangement (10) is provided with an arrangement for supply of oxygen and/or bathing agent for oxygenation and/or treating biomass included in operation within the tarpaulin arrangement (10) .

8. A system (5, 10, 300, 310) as claimed in claim 1, wherein the tarpaulin arrangement (10) and its associated floats (20, 30, 40, 50, 60, 70, 140, 150) are fabricated from one or more flexible plastics materials.

9. A system (5,10, 300, 310) as claimed in any one of the preceding claims, wherein the system (5) is adapted for de- licing salmon.

10. A method of treating biomass within a net, enclosure and cage (80), wherein said method includes steps of: (a) deploying a tarpaulin arrangement (10) around the net, enclosure and cage (80) ;

(b) increasing buoyancy of one or more floats (20, 30, 40, 50, 60) for dispelling a volume of water from the tarpaulin arrangement (10) and thereby from the net, enclosure and cage (80) ;

(c) applying a process to the biomass included within the net, enclosure and cage (80) whose associated volume of water has been reduced in step (b) .

11. A method as claimed in claim 10, wherein deploying a tarpaulin arrangement (10) comprises selectively pressurizing of the floats (20, 30, 40, 50, 60) by liquid with desired pressure, so that they are pressurized to their maximum spatial size so that the tarpaulin arrangement (10) gets distended e.g. generally flat horizontally.

12. A method as claimed in claim 10, wherein the volume of water within the tarpaulin arrangement (10) is subject to forced oxygenation and/or the addition of bathing agent.