Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CAGE FOR FISH FARMING
The present invention generally relates to a cage for fish farming or other
aquatic
organisms. More particularly, the present invention relates to a closed,
flexible cage
for fish farming or other aquatic organisms.
The growing demand for aquatic animals, such as fish, crustaceans and
molluscs, as
a source of food, as well as concerns about over-harvesting and potential
pollution
have led to growth and expansion of the aquaculture industry.
However, the aquaculture industry faces several major challenges. In the case
of
salmonid fish farming, this will relate to the treatment of fish infected by
parasites
such as salmon lice, the escape of fish from floating cages for fish farming
and the
transmission of diseases such as viruses, bacteria and parasites to wild
populations
of salmonids, and discharges of waste products from the floating cages for
fish
farming. These challenges apply especially to fish farming in traditional,
floating
and open cages for fish farming. Such traditional, floating and open cages for
fish
farming consist of a net that forms the physical enclosure for the fish and
which
allows water to flow in and out of the cage for fish farming, as well as a
surrounding buoyancy structure that keeps the net afloat. In addition, such a
traditional, floating and open cage for fish farming includes the necessary
moorings
and anchorage system to keep the cage for fish farming in place. A jumping net
may
further be arranged around the buoyancy structure to prevent the fish from
escaping
by jumping over the buoyancy structure.
In several contexts, problems with salmon lice and access to land have been
mentioned as the main reasons why the volume of farmed fish cannot be
increased
significantly.
Developing new solutions to solve these challenges will be required for
increased
growth in the time ahead. Furthermore, it is a prerequisite for growth to
occur
within defined sustainability criteria, including economic sustainability.
Thus, the
new solutions must also be cost-effective.
The major challenges of viruses, bacteria and parasites have also led to the
development more recently of floating, closed cages for fish farming. Such a
floating, closed cage for fish farming may, for example, consist of a
tarpaulin or
cloth designed to form a cage bag or container in the cage for fish farming.
The
tarpaulin or cloth is made of a dense or water impermeable material. Within
the
tight or sealed bag or container, a conventional net bag may furthermore be
provided.
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Such floating, closed cages for fish farming can be large, often with a square
shape
with sizes of 50x50 meters or a circular shape with a diameter of 50m, and the
depth
can also be considerable and often more than 30 meters. For example, when such
a
tight or sealed cage bag or container is deployed in a body of water, the cage
for
fish farming can be affected by and subjected to great forces, and it is often
felt that
these forces become too large in relation to material choice and the
construction of
the cage for fish farming, whereby the cage bags may tear or rupture.
It is also known that a floating, closed cage for fish farming may be formed
as a
rigid or stiff structure, where the cage for fish farming may be formed as a
composite, steel, or concrete structure.
NO 342245 B 1 relates to a cage for fish farming or other aquatic organisms,
where
the cage for fish farming comprises a container arranged to delimit a volume
of
water in an immersed state, a float collar arranged in an upper part of the
container,
where the floating collar comprises a channel extending diagonally across the
cage
for fish farming.
NO 341911 B 1 relates to a coupling for releasably attaching an enclosure in a
cage
for fish farming to a buoyancy body, the enclosure has a wall with an outside
and an
inside, the enclosure is attached to the buoyancy body which floats on a water
surface, and the buoyancy body has an inside, an outside and an upper side,
where
a fastening eye is attached to the outside of the wall in a portion below the
buoyant
body, a strap connects the fastening eye to the buoyancy body, the strap is
provided
with a first portion and a second portion, and the strap is provided with a
hook in at
least one of the first portion and the second portion. The use of a circular
loop as a
strap in the coupling is also described.
WO 2018/194462 Al relates to A pen system for farming aquatic organisms, the
pen system comprising an outer surrounding rigid structure and an internal,
closed
enclosure; the outer surrounding rigid structure forming an upper portion and
a
lower portion, the pen system further including : - an internal surrounding
connecting element, the closed enclosure being attached to the connecting
element;
- a heave-compensation system comprising a plurality of fluid-filled
cylinders, each
fluid-filled cylinder being hingedly attached, in a first end portion, to the
connecting element, and being hingedly attached, in a second end portion, to
the
inside of the rigid structure.
CN 107926801 A relates to a net cage breeding device for aquaculture, where
the
device comprises a floating platform, a liquid level and a force division
machine;
the floating platform is floated on the liquid level, and the bottom of the
floating
platform is connected with the force division machine; the top of a main rope
is
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connected with the force division machine, and the bottom of the main rope is
connected with the bottom of silt through a fixing base; a protective fence is
arranged on the top of the floating platform and is fixedly connected with the
floating platform; a lower-layer breeding net is located below the floating
platform,
and a lower-layer supporting frame is arranged in the lower-layer breeding
net.
WO 2018/048310 Al relates to a floating installation which can, for example,
be
used for the farming of marine organisms, where the installation comprises a
bag to
establish a main water reservoir, where the walls are fastened to a floating
collar
with at least one inlet pipeline for supply of fresh water and with at least
one outlet
pipeline for discharge of water and waste from the net cage. The installation
can
also be used for storing of water, purification of water and for the treatment
of
water. Also described is a method for treatment of water that is supplied to a
cage in
a cage installation.
NO 343021 B 1 relates to a dense or sealed bag for farmed cages equipped with
elongated channels for receiving liquid for stiffening the bag, and a method
for
regulating the rigidity of a flexible cage bag.
The present invention aims to alleviate or reduce at least one of the
disadvantages
of the prior art, or at least to provide a useful alternative to the prior
art.
A further object of the present invention is to provide a cage for fish
farming which
is easy to assemble, remove, replace and maintain.
These objects are achieved, in accordance with the present invention, with a
closed,
flexible cage for fish farming as set forth in the following description and
as defined
in the characterizing portion of the independent claim. Further embodiments of
the
invention are defined in the dependent claims.
The present invention relates to a closed, flexible cage for fish farming or
other
aquatic organisms, where the closed, flexible cage for fish farming comprises
a
container which delimits a volume of water in an immersed state and which
forms
the enclosure for fish, where an upper portion of the container is connected
to at
least one floating collar, where the at least one floating collar is arranged
around an
inner circumference of the container and connected to the container.
According to one embodiment, the container in the closed flexible cage for
fish
farming may be made of a cloth or tarpaulin made of a substantially
impermeable
material, whereby the container will form an effective barrier against toxic
algae,
algal toxins and/or crustacean parasites such as salmon lice.
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By arranging the floating collar around the inner circumference of the
container,
jerking forces in the cloth or tarpaulin may be eliminated, where these
jerking
forces are caused by hydrostatic and hydrodynamic forces from waves outside
the
closed, flexible cage for fish farming.
Jerking forces in the cloth or tarpaulin may also be caused by waves (also
called
sloshing) which are formed within the closed, flexible cage for fish farming,
where
the hydrostatic and hydrodynamic forces from these internal waves may also be
dampened by arranging the floating collar around the inner circumference of
the
container.
As long as the water inside the container approximately is at rest, which will
be the
case for waves with periods of 1-2 seconds and up to 5-6 seconds and maybe
more,
the container will function almost like a rigid body.
The container in the closed, flexible cage for fish farming may be made from a
single piece of a cloth or tarpaulin and which further is designed to form the
enclosure for fish, but it is also conceivable that the container may be made
from a
number of wall and bottom panels which are appropriately connected to each
other
to form the enclosure for fish.
In one embodiment of the present invention, the wall and bottom panels may be
made of the same material, but it is also conceivable that the wall and bottom
panels
may be made of different materials and/or combinations of materials, where the
materials may vary with respect to strength. flexibility, thickness etc.
In one embodiment, the closed, flexible cage for fish farming may be made from
a
plurality of wall panels assembled to form the wall of the container and a
plurality
of bottom panels assembled to form the bottom of the container. The wall
panels
may further be assembled such that an upper part of the wall of the container,
i.e.
the part of the wall of the container which is closest to a surface of water
in the
body of water, is formed of a thicker and less flexible material than a lower
part of
the wall of the container, as the upper part of the container is being
subjected to
greater forces or loads from waves and winds than the lower part of the
container,
both from the outside and inside the closed, flexible cage for fish farming.
Similarly, bottom panels in a lower part of the bottom of the container may be
made
of a thicker and less flexible material than an upper part of the bottom of
the
container, as the lower part of the bottom is being subjected to greater loads
than
the upper part of the bottom, as bottom waste etc. will gather in the lower
part of
the bottom.
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The wall and bottom panels may further be made of one or more layers of the
same
material or a combination of materials.
The floating collar arranged around the inner circumference of the container
may be
5 arranged to extend continuously around the entire inner circumference of
the
container. It is to be understood, however, that the floating collar may also
be
arranged to extend discontinuously around the inner circumference of the
container,
whereby the floating collar may, for example, be divided into a plurality of
"sub-
floating collars" which are arranged spaced apart. The "sub-floating collars"
may be
made of the same or different length. For example, in one embodiment, the side
of
the closed, flexible cage for fish farming which is most exposed to waves and
wind
loads may be provided with a "sub-floating collar" which covers half the
circumference of the closed, flexible cage for fish farming, while the other
half of
the circumference of the closed, flexible cage for fish farming which is
exposed to
minor stresses from waves and winds may be equipped with a number of smaller
"sub-floating collars" which are arranged spaced apart from each other.
It could also be envisaged that two floating collars are arranged around the
inner
circumference of the container, where the two floating collars may be arranged
side
by side or above each other, so as to provide necessary buoyancy and/or
reserve
buoyancy. One skilled in the art will understand that more than two floating
collars
may also be used.
In one embodiment where two floating collars are used, one floating collar may
be
arranged to extend continuously around the entire inner circumference of the
container, while the other floating collar may comprise a plurality of "sub-
floating
collars" which are arranged spaced apart from each other.
The floating collar may be made of a suitable material which provides the
desired
buoyancy, or the floating collar may be made as a hose which can be filled
with air.
In one embodiment, the floating collar may be arranged to be fully submerged
or
immersed in a body of water, but it should be understood that the floating
collar
may also be partially submerged in the body of water. If two floating collars
arranged side by side are used, both floating collars may be fully or
partially
submerged in the body of water. If two floating collars arranged above one
another
are used, one floating collar may be fully or partially submerged in the body
of
water, while the upper floating collar may be disposed above the water surface
of
the body of water.
The floating collar or floating collars may also be ballastable and
deballastable so
as to be able to position the closed, flexible cage for fish farming higher or
lower in
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the body of water, whereby the floating collar or floating collars will then
be
suitably connected to a system which allows ballasting or deballasting of the
floating collar(s). One of ordinary skill in the art will know how to design a
floating
collar and system that allows ballasting or deballasting and this is not
described
further herein.
In one embodiment, the closed flexible cage for fish farming may further
comprise a
first element which also is arranged around the inner circumference of the
container, whereby this first element may be used, for example, to support the
container by appropriately connecting the container to the first element
and/or the
floating collar. This first element may, for example, be conceived to be a
railing
and/or a foundation for equipment for the closed, flexible cage for fish
farming.
The first element may be arranged to extend continuously or discontinuously
around
entire or part of the inner circumference of the container. The first element
may
then be divided into a number of "sub-elements" which are arranged spaced
apart
from each other.
In one embodiment, the first element may be a separate, individual and
independent
element which may in appropriate ways be connected to the floating collar, but
it
should be understood that the first element may also be an integral part of
the
floating collar. One skilled in the art will understand how the first element
and the
floating collar can be integrated with each other, whereby this is not
described
further herein.
The first element may be disposed over a surface of the body of water, but in
some
embodiments of the present invention it is also conceivable that the first
element
may be arranged at least partially submerged in the body of water.
According to one embodiment, the closed, flexible cage for fish farming may
also
comprise a second element arranged around the inner circumference of the
container. The second element may be used, for example, to support the
container,
to be a fixing for the container and/or floating collar, and/or to be a
foundation for
equipment for the closed, flexible cage for fish farming.
The second element may, corresponding to the first element, be arranged to
extend
continuously or discontinuously around the entire or part of the inner
circumference
of the container. The second element may then be divided into a number of "sub-
elements" which are arranged spaced apart from each other.
In one embodiment, the second element may be a separate, individual and
independent element which may in appropriate ways be connected to the floating
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collar, but it should be understood that the second element may also be an
integral
part of the floating collar. One skilled in the art will understand how the
second
element and the floating collar can be integrated with each other, whereby
this is
not described further herein.
The second element may be arranged submerged in the body of water, but in some
embodiments of the present invention it is also conceivable that the second
element
may be arranged at least partially above the surface of the body of water.
By the term equipment for the closed, flexible cage for fish farming it should
be
understood components or elements needed for working and/or operation of the
fish
farm, throughout the life of the fish farm and under all operating conditions,
where
this may, for example, be moorings for the cage for fish farming, pumps,
hoses,
waste handling system or the like.
The floating collar which is arranged around the inner circumference of the
container may be designed to have a circular, a square, a triangular, or a
polygonal
shape. If more than one floating collar is used, the floating collars may have
the
same or different shape.
The closed flexible cage for fish farming may also include necessary moorings
and
anchorage system to hold the closed flexible cage for fish farming in place.
One
skilled in the art will know how to design moorings and anchor systems,
whereby
this is not described further herein.
The closed, flexible cage for fish farming may also comprise a water exchange
system, wherein the water exchange system may comprise one or more pumps, one
or more filters, etc.
The following are examples of preferred embodiments illustrated in the
accompanying drawings, in which:
Figure 1 shows schematically a side section of a closed, flexible cage for
fish
farming according to the prior art,
Fig. 2A shows schematically a side view of a closed, flexible cage for fish
farming
according to the present invention;
Figure 2B shows schematically a side view of an alternative embodiment of the
closed, flexible cage for fish farming according to figure 2A,
Figure 3 shows in greater detail a section of the left corner of the closed,
flexible
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cage for fish farming according to figure 2A or 2B,
Figure 4A shows a section of an alternative embodiment of the closed, flexible
cage
for fish farming according to figure 2A or 2B,
Figure 4B shows a section of another alternative embodiment of the closed,
flexible
cage for fish farming according to figure 2A or 2B, and
Figure 5 show embodiments of a floating collar used with a closed, flexible
cage for
fish farming according to the present invention.
Figure 1 shows a closed, flexible cage for fish farming 0 according to the
prior art,
where the closed, flexible cage for fish farming 0 comprises a bag P which is
connected in suitable ways to a buoyancy element B and a railing R arranged
around an outer circumference of the cage for fish farming 0. The closed,
flexible
cage for fish farming 0 is connected to a seabed (not shown) through a
suitable
anchoring system (not shown), so as to hold the closed, flexible cage for fish
farming 0 in place.
Figure 2A shows a schematic side view of a closed, flexible cage 1 for fish
farming
according to the present invention, where the closed flexible cage 1 for fish
farming
comprises a container 2 which delimits a water volume W, in an immersed or
submerged state, below a water surface S and which further forms an enclosure
for
fish.
The container 2 is made of a cloth or tarpaulin which is substantially fluid
impermeable, for example a strong and flexible composite material, which helps
to
minimize escape risk, and which will also form an effective barrier against
toxic
algae, algal toxins and/or crustacean parasites such as salmon lice.
As shown in figure 2A, the container 2 in the closed, flexible cage 1 for fish
farming is made from a single piece of a cloth or tarpaulin.
A floating collar 3 is further arranged around an inner circumference of the
container 2, i.e. on an inside of the defined water volume W, where the
floating
collar 3 is arranged extending around the entire inner circumference of the
container
2. The floating collar 3 is further arranged partially submerged in a body of
water.
Figure 2B shows an alternative embodiment of the closed, flexible cage 1 for
fish
farming according to figure 2A, where the container 2 in this embodiment is
made
of a number of wall and bottom panels 2a-2d or wall and bottom pieces 2a-2d
which
in appropriate ways are connected to form the container 2.
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A plurality of wall panels 2a-2b will then form the wall of the container 2,
while a
number of bottom panels 2c-2d will form the bottom of the container 2. The
various
wall and bottom panels 2a-2d will in appropriate ways be connected to each
other to
form the container 2.
In one embodiment, the wall panels 2a-2b may be made of a different material
than
the bottom panels 2c-2d are made of, where the material may vary according to
strength, flexibility, thickness etc.
Furthermore, the wall panels 2a-2b may also be made of different materials,
where
the different materials may vary with respect to strength, flexibility,
thickness etc.
Similarly, the bottom panels 2c-2d may be made of different materials, where
the
different materials can vary with respect to strength, flexibility, thickness
etc.
For example, the wall panels 2a which are arranged in an upper part of the
wall of
the container 2 may be made of a thicker and less flexible material than wall
panels
2b arranged in a lower part of the wall of the container 2. In this way, the
upper part
of the wall of the container 2 may be made stronger, this part of the wall is
being
subjected to greater forces and loads from, for example, waves and wind, than
the
lower part of the wall of the container 2 wall. Together with the arrangement
of the
floating collar 3 within the container 2, this could lead to a less
deformation of the
closed, flexible cage 1 for fish farming.
The upper part of the wall of the container 2 is to be understood as to be the
part of
the wall which is closest to the water surface S, while the lower part of the
wall of
the container 2 is to be understood to be the part of the wall which is
closest to the
bottom of the container 2.
Similarly, the bottom panels 2d which are arranged in the lower part of the
bottom
of the container 2 may be made of a thicker and less flexible material than
bottom
panels 2c in the upper part of the bottom, as the lower part of the bottom is
being
subjected to greater loads than the upper part of the bottom, as bottom waste
etc.
will be collected in the lower part of the bottom.
The upper part of the bottom of the container 2 is to be understood to be the
part of
the bottom which is closest to the lower part of the wall of the container 2,
while the
lower part of the bottom is to be understood to be the part of the bottom
which
constitutes the lowest point of the container 2.
A floating collar 3 is further arranged around an inner circumference of the
container 2, i.e. on an inside of the delimited water volume, where the
floating
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collar 3 is arranged extending around the entire inner circumference of the
container
2. The floating collar 3 is further arranged partially submerged in a body of
water.
Figure 3 shows in greater detail a section of a left corner of the closed,
flexible cage
5 for fish farming 1 according to figure 2A or 2B, where it is seen that
the floating
collar 3 is arranged partially submerged in the body of water. A first element
4 is
furthermore also arranged to extend around the inner circumference of the
container
2, where the first element 4 in appropriate ways is connected to the floating
collar 3.
Alternatively, the first element 4 may be an integral part of the floating
collar 3.
10 The first element 4 will further be a support for the container 2, so
that a
deformation of the container in waves and wind to a greater extent is
prevented. The
first element 4 may also be used as a fixing for the container 2, whereby an
upper
part of the container 2 may then in appropriate ways be attached to the first
element
4.
In one embodiment, the floating collar 3 may be arranged to extend around the
entire inner circumference of the container 2, while the first element 4 may
comprise a plurality of "sub-elements" which are spaced apart each other.
Alternatively, the first element 4 may be arranged to extend around the entire
inner
circumference of the container 3, while the floating collar 3 may comprise a
plurality of "sub-floating collars" which are arranged spaced apart each
other.
The "sub-elements" of the first element 4 and/or the "sub-floating collars" of
the
floating collar 3 may be made in the same or different size and/or length, as
the first
element 4 and/or the floating collar 3 may be used as a foundation for
equipment
used in connection to the closed, flexible cage for fish farming 1. Such
equipment
may be components or elements required for working and/or operation of the
fish
farm throughout its lifetime and under all operating conditions of the fish
farm,
such as moorings, pumps, hoses, waste handling system etc.
The closed, flexible cage 1 for fish farming comprises also a second element 5
which may be arranged to extend around the inner circumference of the
container 2.
The second element 5, which is a free-standing element, is in appropriate ways
connected to the floating collar 3. A person skilled in the art will however
understand that the second element 5 may also be an integral part of the
floating
collar 3. The second element 5 may, similarly to the first element 4, be used
as a
fixing for the container 2, so that a deformation of the container 2 in waves
and
wind to a greater extent is prevented.
The second element 5 may also in some embodiments of the closed, flexible cage
for fish farming 1 be used as a fixing for the container 2, whereby an upper
area of
the container 2 then in appropriate ways can be attached to the second element
5.
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In one embodiment, the floating collar 3 may be arranged to extend around the
entire inner circumference of the container 3, while the first member 4 and
the
second member 5 may comprise a plurality of "sub-elements" which are arranged
spaced apart each other around the inner circumference. of the container 2.
Alternatively, the first element 4 and/or the second element 5 may be arranged
to
extend continuously around the entire inner circumference of the container 3,
while
the floating collar 3 may comprises a plurality of "sub-floating collars"
which are
arranged at a distance from each other.
The "sub-elements" of the first element 4, the second element 5 and/or the
"sub-
floating collars" of the floating collar 3 may be made in the same or
different size
and/or length, as the first element 4, the second element 5 and/or the
floating collar
3 could be used as a foundation for equipment used in connection with the
closed,
flexible cage for fish farming 1. Such equipment may be components or elements
needed for working and/or operation of the fish farm throughout its lifetime
and
under all operating conditions of the fish farm, such as moorings, pumps,
hoses,
waste handling system etc.
In one embodiment, the first member 4 may be a handrail to allow fish farmers
to
move around the closed, flexible cage for fish farming 1. The first member 4
may
then appropriately be made from metal, aluminum or the like.
In another embodiment, the first element 4 and the second element 5 may be
made
of a plastic or composite material, foam material or the like, or a
combination
thereof, where the materials are selected to be able to support the container
2, be
fixing to the container 2 and/or be a foundation for equipment.
The second element 5 is arranged to be immersed in the body of water.
Figure 4A shows a section of an alternative embodiment of the closed, flexible
cage
for fish farming 1 according to figure 2A or 2B, in which the container 2 can
be
designed as described in relation to figure 2A or 2B. Two floating collars 3
are
further arranged around an inner circumference of the container 2, i.e. on an
inside
of the delimited water volume W of the closed, flexible cage for fish farming
1.
One of the floating collars 3 is arranged to lie within the other floating
collar 3, and
both floating collars 3 are further arranged partially submerged in the body
of
water.
The outer floating collar 3 has a circular shape, while the inner floating
collar 3 has
a polygonal shape. In this embodiment, the outer floating collar 3 will extend
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continuously around the inner circumference of the container 2, while the
inner
floating collar 3 comprises a plurality of "sub-floating collars" which are
arranged
spaced apart each other.
Figure 4B shows a section of an additional alternative embodiment of the
closed,
flexible cage for fish farming 1 according to figure 2A or 2B, where the
container 2
can be designed as described in relation to figure 2A or 2B.
Two floating collars 3 are further arranged around an inner circumference of
the
container 2, i.e. on an inside of the delimited water volume of the closed,
flexible
cage for fish farming 1.
A lower floating collar 3, which is arranged partially submerged in the
delimited
water volume W, has a square shape, while an upper floating collar 3, which is
arranged on the lower floating collar 3, has a triangular shape. The upper
floating
collar 3 is further arranged completely above the water surface S and will be
able to
provide additional buoyancy if required.
In this embodiment, both the lower and upper floating collars 3 will extend
continuously around the inner circumference of the container 2.
The floating collar or floating collars 3 in the illustrated embodiments may
further
be designed to be ballastable and deballastable, so as to be able to position
the
closed, flexible cage for fish farming 1 higher or lower in the body of water,
where
the floating collar 3 or floating collars 3 then is/are connected to a system
which
allows ballasting/deballasting of the floating collar(s) 3.
Furthermore, the shown embodiments of the closed, flexible cage for fish
farming 1
will, although not shown, also include necessary moorings and anchorage
systems
to hold the closed, flexible cage for fish farming 1 in a desired position.
Figure 5 shows alternative geometric shapes that a floating collar 3 may have
in the
closed, flexible cage for fish farming 1, where it is seen that the floating
collar 3, in
addition to have a rectangular shape, can also be made with other geometric
shapes,
such as a circular, a square, a triangular or polygonal shape.
For example, if two floating collars 3 are used in the closed, flexible cage
for fish
farming 1, the floating collars 3 may be designed to have the same or
different
geometric shape.
Furthermore, it should be understood that if the floating collar 3 is arranged
to
extend discontinuously around the inner circumference of the container 2,
i.e., that
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the floating collar comprises a plurality of "sub-floating collars", then the
"sub-
floating collars" 3 may be of the same or different shape.
The invention has now been explained with several non-limiting examples. One
skilled in the art will appreciate that a variety of variations and
modifications may
be made to the closed, flexible cage for fish farming as described within the
scope
of the invention as defined in the appended claims.
15
25
