GB2212609A - Counting living aquatic animals immersed in water - Google Patents
Counting living aquatic animals immersed in water Download PDFInfo
- Publication number
- GB2212609A GB2212609A GB8727361A GB8727361A GB2212609A GB 2212609 A GB2212609 A GB 2212609A GB 8727361 A GB8727361 A GB 8727361A GB 8727361 A GB8727361 A GB 8727361A GB 2212609 A GB2212609 A GB 2212609A
- Authority
- GB
- United Kingdom
- Prior art keywords
- light
- passageways
- passageway
- fish
- shadow
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
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Classifications
-
- G—PHYSICS
- G06—COMPUTING OR CALCULATING; COUNTING
- G06M—COUNTING MECHANISMS; COUNTING OF OBJECTS NOT OTHERWISE PROVIDED FOR
- G06M7/00—Counting of objects carried by a conveyor
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
- A01K61/00—Culture of aquatic animals
- A01K61/90—Sorting, grading, counting or marking live aquatic animals, e.g. sex determination
-
- G—PHYSICS
- G06—COMPUTING OR CALCULATING; COUNTING
- G06M—COUNTING MECHANISMS; COUNTING OF OBJECTS NOT OTHERWISE PROVIDED FOR
- G06M1/00—Design features of general application
- G06M1/08—Design features of general application for actuating the drive
- G06M1/10—Design features of general application for actuating the drive by electric or magnetic means
- G06M1/101—Design features of general application for actuating the drive by electric or magnetic means by electro-optical means
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- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Marine Sciences & Fisheries (AREA)
- Animal Husbandry (AREA)
- Biodiversity & Conservation Biology (AREA)
- Farming Of Fish And Shellfish (AREA)
Abstract
Apparatus for counting living aquatic animals, such as salmon parr and salmon smolts, whilst they are immersed in water, comprises one or more narrow passageways 11 through which the animals are constrained to pass in a predetermined direction. Light is directed horizontally across the or each passageway towards an array of light detectors 29 which are arranged to produce a signal corresponding to the height of the shadow of each animal as it passes. The peak of each signal is detected at 32 and, after stabilisation by a pulse former 33, the peaks are counted at 37, to indicate the number of animals that have passed through the passageway(s). The passageways can be interchanged with passageways of different cross-section to suit fish of different sizes or shapes, and a grading screen can be placed over the entrance to the passageways to restrict the size of fish that can enter the apparatus. <IMAGE>
Description
COijNTThTG LIVING AQUATIC ANIMALS IbDIERS < D IN WATER Thins invention is concerned with apparatus for counting living aquatic animals whilst they are immersed in water.
Although such apparatus could be utilised for counting a range of different types of fish and possibly crustaceans,, this invention is particularly (but not exclusively) concerned with apparatus for counting live fish used for fish farming.
The farming of Atlantic salmon and other species of salmon is a rapidly expanding industry operating on an international scale. The production cycle is quite complex and is totally dependent on the hatching of ova in fresh water to produce aelvin which, after a few weeks, become free-swimming fry.
The fry swim to the surface to inflate their air bladders and a few days later start Seeding, eventually growing into parr which in due time become smolts. Elen smolting occurs, the fish can then be moved for the first time into salt water where they will grow into salmon. Whilst there are satisfactory techniques for assessing the number of ova in a batch, the mobility of fry, parr and smolts has hitherto necessitated a very crude and time-consuming traditional teclulique to effect a count.Such traditional technique involves nettling the fish in small batches from a first tank and then releasing them on an inclined chute leading to a second taii1, the fish being individually counted,as they slide doll the chute, by two or more persons standing next to the chute. The ova of Atlantic salmon typically hatch between- Jaaary and larch and, if properly managed, a significant proportion of these fish will smolt during early May of the follolsing year - such fish are given the designation S1. The remainder of these fish will fail to smolt at this time, but will probably do so the next following spring being designated S2, with the remainder smolting in subsequent years and being designated S3, s4 and so on.
For the producer of salmon smolts it is, of course, much more attractive to produce S1 smolts rather than have to feed and keep any parr that fail to smolt for a further year to produce S2 smolts which, although much larger than S1 smolts, currently command about the same market price. There are many factors governing whether any particular fish will, or will not, smolt in its first year, but the best guide is its rate of growth. For this reason, smolt producers typically size-grade their fish several times during the year to isolate the faster growing fish which are then designated "potential S1", the slower growing fish being designated "potential S2".To be able to assess the projected production of a hatchery, it is therefore essential to count both the number of fish achieving a particular size-grade and the number that are "graded out". Further counts are necessary if any of the fish are to be sold. However, the most critical count is when smolts are either sold to a third party, or are transferred to sea cages or on-shore salt water talcs in which latter event it is important to lzlow how many smolts are put into each cage or tu A significant proportion of smolts are trmlsferred in well-boats to the eventual purchasers and there is then the particularly difficult problem of counting a predetermined number of fish out of the well-boat into each sea cage, usually under severe time constraints and sometimes under adverse weather conditions. Nle counting of smolts is further complicated in that they are particularly delicate and are very prone to scale loss whelp handled out of water, the resultant loss of scales providing an entry point for a range of viral, bacterial and fungal infections at a very critical time of the young salmon's life - that is its transfer to sea water and the associated osmotic shock.
The object of thts invention is to provide apparatus for counting aquatic animals, such as salmon fry, parr and smolts, which will operate whilst they are still immersed in water, thereby reducing their handling and correspondingly reducing consequential damage.
According to the present invention apparatus for counting living aquatic animals, whilst they are immersed in water, includes a narrow passageway through which the animals are to move in a predetermined direction, illumination means whereby light is able to cross the passageway towards a light detector means arranged to detect the shadow of each animal as it passes, the light detector means being arranged to produce a signal corresponding to the height of the shadow, meals for-detect-ng the peak value of such signal, and a counter device for counting the number of peak values.In this maunder the narrolçness of the passageway can be selected to be only slightly larger than the maximum depth or width of the fish to be counted thereby avoiding complete overlapping of fish as they pass the light detector means, and the counting of the peale values of -the signals enables the fish to be counted even though successive fish may be overlapping tail-to-head.
Preferably the illumination means and the light detector means are arranged so that the light will cross the passageway substantially horizontally whereby the height of the shadow produced by each animal is a measure of its vertical depth.- Wits salmon the maximum vertical depth coincides with the position of its dorsal fin which therefore generates the peak height of its shadow and enables a very precise count to be made unless two fish pass the light detector means exactly overlapped.It is of course possible for the illumination means and the light detector means to be arranged so that the light will cross the passageway in other directions, for instance vertically. This latter orientation would be suitable for counting flat fish, but would give a much poorer indication of the peak value for fish such as salmon as the height of the shadow is in this case a measure of the width of the fish.
q1iilst the illumination means could merely be a translucent wall defining the passageway, or a window in the passageway, permitting ambient light to enter, it is preferred that the illuniination means is a light emission device of predetermined intensity for emitting light across the passageway towards the light detector means.
Preferably the light detector means is an array of light detectors arranged to detect the height of each shadow. The means for detecting the peale value of each signal is preferably a peak detector which is connected to the counter device through a pulse former.
The performance of the apparatus can be increased by providing
a plurality of narrow passages arranged in parallel whereby the animals can move in the XredetermSned direction
through any of the passageways, each passageway being provided with a respective light detection means, the illumination means being arranged so that light is able to
cross each passageway towards the respective light detection means, each light detection means being arranged to produce a signal corresponding to the height of the shadow of any animal passing along the respective passageway, means being provided for detecting the peals value of each
signal, and a counter device for counting the number of peals values.With this arrangement the means for detecting the peali value of each signal is preferably a number of peal.
detectors connected one to each of the light detection means, each peals detector being arranged to actuate a respective pulse former, and the pulse formers being arranged to drive the counter device through a multiplexer. Each light detection means preferably includes an array of light detectors arranged to detect the height of each shadow0
Preferably there are eight, or a multiple of eight, passageways as these numbers are convenient for interfacing with electronics equipment such as multiplexers0
The passageways may be split into two parallely spaced sets and the illumination means is one or more light emission devices arranged between the two sets. lii tis event, the apparatus may include a hollow frame having three parallel limbs, the central limb extending between the two sets of passageways and housing the illumination means, and the two outer limbs housing the light detection means. A ballast bar may be arranged to interconnect the free ends of the limbs thereby locating the hollow frame in position relative to the passageways and at least negating the buoyancy of the hollow frame.
The passageways may be defined by a moulding of translucent material, Elen the passageways are split into two sets, each set may alternatively be formed as a separate moulding.
The or every passageway may be interchangeable with a passageway of different cross-section to suit aquatic animsls of different size or shape. Alternatively, a grading screen may be provided for restricting the size of aquatic animal that can enter the or every passageway.
The counter device preferably has a control to pre-set the number of aquatic animals to be counted and is arranged to give a signal when the pre-set number of aquatic animals has, or nearly has, passed through the apparatus.
The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is an isometric view of apparatus for counting fish whilst they are immersed in water;
Figure 2 is a horizontal section taken on the line 2-2 of
Figure 1, and
Figure 3 is an enlarged transverse section taken on the line 3-3 of Figure 2 and additionally shows the electronic circuitry.
With reference to Figure 1, the apparatus comprises a moulding 10 of transparent or translucent thermoplastics material defining eight narrow tubular passageways 11 of square cross-section formed integral with an end plate 12, and a moulded hollow frame 13 which has three vertically extending parallel limbs 14, 15 and 16. The top of the frame 13 is closed by a sealing plate 17 having a central hollow connector 18 for attacllment to an unshown wiring duct permitting waterproof electrical connections to be made to fish detection equipment housed within the hollow frame 13.
A ballast bar 19 interconnects the lower ends of the limbs 14, 15 and 16 and-is secured in Rosition by countersulll{ set screws 20 (see Figure 3). -11:1 this manner the hollow frame 13 is firmly located in positiomrela-tive to the eight passageways 11 and the weight of the ballast bar 19 is chosen to at least negate any buoyancy of the hollow frame 13.
The eight narrow passageways 11 are thus held between the outer limbs 14 and 16 of the hollow frame 13 and are split into two parallely-spaced sets of four by the central limb 15 which extends between them. The apparatus is provided with eight passageways as this number interfaces with the multiplexer 21 used in the electronic circuitry shown in
Figure 3.
As illustrated, each of the narrow passageways 11 is defined by an individual wall and is of constant cross-section. For this reason, there are horizontal gaps between the passages of each set and spacers 22 can be positioned in these gaps to ensure that the ballast bar 19 will clamp the apparatus firmly together. Although the illustrated construction is preferred, each set of four passageways could be forn'.eo a separate moulding - also each set of four passageways could be moulded without the horizontal gaps.
By detaching the ballast bar 19 it is, of course, quit an easy matter to replace the moulding 10 with a moulding of generally similar form but having passageways of different cross-section to suit fish of different size or shape From the depictions of fish shown in Figures 2 and 3, it will be noted that a square profiled passageway gives plenty of lateral space for tlie fish to bend as they swim through and that this space is large enough to permit two fish possibly to swim side-by-side and therefore give rise to an undercount.
For this reason it is desirable to constrain the fish to prevent them swimming side-by-side in the region of the fish detection equipment. This is best achieved by means of a grading screen 23 which slots into a guide 24 formed integral with the end plate 12. The grading screen 23 is provided with eight rectangular apertures 25 which, when the grading screen is in position, register vertically with the passageways 11 but cause a horizontal restriction on both sides as shown in
Figure 2. These horizontal restrictions are selected to prevent fish entering each passageway two or more abreast and are positioned about one fish length-azray from the hollow frame 13 where the fish detection is to occur.With these proportions it is most improbable that the second of any two fish entering one of the apertures 25 will have been able to catch up with the leading fish by the time it is identified by the fish detection equipment.
It is well-lrnown that the width of a fish is proportional to its weight and that this relationship is used when grading salmon parr through parallel slots of known spacing. By having a series of grading screens with apertures 25 of different widths, it is therefore possible to use the apparatus to grade-out fish whilst simullsaneouslr counting them.
As shown ill Figure 2, the end plate 12 can be bolted into all aperture of a fish collecting tanlc 26 so that the fish can only escape through the apertures 25 and thus through the passageways 11 in which they will be counted in a manner which will be described later. hen the fish to be counted are, for example, salmon fry, parr or smolt carried in a transport talJ, the structure 26 could merely comprise a tubular connector for coacting with the conventional tanli outlet, However, when the fish are to be counted from a well-boat, the structure could form the bottom of a hopper into which the fish are transferred. In this event it is desirable to ensure that all adequate flow of water passes with the fish through the apertures 25.
As the fish pass between the limbs of the hollow frame 13 they are courted in the following manner:
A light emission device, in the form of a miniature quartz tube 27 is housed in the centre limb 15 and extends across the vertical faces of all eight passageways so that each passageway is horizontally illuminated to the same extent. If desired, the miniature quartz tube 27 can be replaced by a vertical series of light emitting diodes and means can be provided for adjusting the light intensity to take account of variations in the colouration and turbidity of the water in the passageways 11.
The outer- limbs 14 and 16 house light detection means 28 for receiving the light emitted from the quartz tbe 27.
As shown in Figure 3, each light detection means 28 comprises a vertical array of variable response light detectors 29e These light detectors 29 are split into a separate group for each of the passageways 11 whereby each group gives a joint output to a common control line 30.
Typically each detector 29 will generate an increment of voltage if it is receiving light of the appropriate intensity, and each group of detectors is arranged to produce a potential of, say, 5 volts when every detector in that group is receiving light. Any body passing along the associated passageway 11 between the quartz tube 27 and the associated group of detectors 29 generates a shadow which interrupts the passage of the light to one or more of the detectors 29 and causes a momentary drop in the voltage output. As tie potential applied to each control line 30 is generated by a group of detectors covering the entire side of the associated passageway, the drop in potential as a body passes by is a measure of the height of the shadow produced by the body.As a fish passes a group of detectors, the voltage will therefore vary according to the profile of the fish and will be at its lowest when the dorsal fin passes by. Thus each group of detectors will produce a signal, in the form of a voltage reduction, as each fish passes by, and this signal will reach a peak value as the dorsal fin passes. the detectors With reference to Figure 3, the joint output of each group of detectors is passed bWr the control line 30 through an amplifier 31 to a peak detector 32 which is designed to produce a pulse whenever it receives the peak value of a signal. As the length of the signal passed to control line 30 is dependent on both the length of the fish and the speed that it is travelling, the pulses produced by the peak detector 32 will be of variable length.For this reason each pulse from the peale detector 32 is used to trigger a pulse former 33 which is designed to generate a very precise pulse of very short duration suitable for feeding to the multiplexer21. Each other group of detectors 29 passes its output into an individual control line which is connected through a channel identical to channel 34 to the appropriate input 35 to the multiplexer 21.
An address generator 36 produces a binary coded input to drive the multiplexer 21 so that it will scan the outputs of the eight pulse formers in the eight channels 34. The multiplexer 21 must, of course, be driven sufficiently quickly that it is able to scan all eight channels within the time of a single pulse from one of the pulse formers thereby ensuring that all pulses are counted, but that no pulse is counted more than once. The multiplexer 21 thus collates all of the counting information and generates a series of pulses which drive a counter 37. A control 38 for the counter 37 is arranged so that the counter can be given a pre-set number of fish to be counted. As the pre-set number of fish has nearly beencownted, the control is arranged to give a signal, such as an audible warning, so that the passage of fish can be slowed down untIl the exact pre-set number have passed through the passageways 11.
If desired, the overall level of illumination around the apparatus can be minimised by painting the outer faces of the limbs 14, 15 and 16 and the cover 17 with an opaque layer. To prevent reflection of light from the curved surface of a fish in one passageway towards the light detectors of another passageway, the spacers 22 are preferably made of an opaque material.
Claims (17)
1. Apparatus for counting living aquatic animals, whilst
they are immersed in water, including a narrow passageway
through which the animals are to move in a predetermined
direction, illumination means whereby light is able to
cross the passageway towards a light detector means which
is arranged to detect the shadow of each animal as it
passes, the light detector means being arranged to produce
a signal corresponding to the height of the shadow, means
for detecting the peak value of each signal, and a counter
device for counting the number of peak values.
2. Apparatus, according to Claim 1, in which the illumnation mealls and the light detector means are arranged so that
the light will cross the passageway substantially horizontally whereby the height of te e shadow produced by each animal is a measure of its vertical depth.
3. Apparatus, according to Claim 1 or 2, in which the
illumination means is a light emission device of
predetermined intensity for emitting light across the
passageway towards the light detector means.
4. Apparatus, according to any preceding claim, in which the
light detector means includes an array of light detectors
arranged to detect the height of each shadow.
5. Apparatus, according to any preceding claim, in which the
means for detecting the peak value of each signal is a peak detector which is connected to the counter device
through a pulse former.
6 Apparatus, according to any of Claims 1 to 3, in which
there are a plurality of narrow passageways arranged in
parallel whereby the animals can move in the predetermined
direction through any of the passageways, each passageway
is provided with a respective light detection means, the
illumination means is arranged so that light is able to
cross each passageway towards the respective light detection
means, each light detection means is arranged to produce a
signal corresponding to the height of the shadow of any animal passing along the respective passageway, means for
detecting the peak value of each signal, and a counter
device for counting the number of peak values.
7. Apparatus, according to Claim 6, in which the means for
detecting the peak value of each signal is a number of peak
detectors connected one to each of the light detection
means, each peak detector is arranged to actuate a respective
pulse former, and the pulse formers are arranged to drive
the counter device through a multiplexer.
8. Apparatus, according to Claim 6 or 7, in which each light
detection means includes an array of light detectors
arranged to detect the height of each shadow.
9. Apparatus, according to any of Claims 6 to 8, in which there
are eight, or a multiple of eight, passageways.
10. Apparatus, according to Claim 9, in which the passageways
are split into to parallely spaced sets and the illumination
means is one or more light emission devices arranged between
the two sets.
11. Apparatus, according to Claim 10, including a hollow
frame having three parallel limbs,7 the central limb
extending between the two sets of passageways and housing
the illumination means, and the two outer limbs housing
the light detection means.
12. Apparatus, according to Claim 11, in which a ballast bar
interconnects the free ends of the limbs thereby locating
the hollow frame in position relative to the passageways
and at least negating the buoyancy of the hollow frame0
13. Apparatus, according to any of Claims 9 to 12, in which the
passageways are defined by a moulding of translucent material.
14. Apparatus, according to any of Claims 10 to 12, in which each
set of passageways is formed as a moulding of translucent
material.
15. Apparatus, according to any preceding claim, in which the,
or every, passageway is interchangeable uth a passageway of
different cross-section to suit aquatic animals of different
size or shape.
16. Apparatus, according to any of Claims 1 to 14, including a
grading screen for restricting the size of aquatic animal
that can enter the or every passageway9
17. Apparatus, according to any preceding claim, in which the
counter device has a control to pre-set the number of
aquatic animals to be counted and is arranged to give a signal
when the pre-set number of aquatic animals has, or nearly has,
passed through the apparatus.
18* Apparatus for counting living aquatic animals, whilst they are immersed in water, substantially as described
herein with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8727361A GB2212609A (en) | 1987-11-23 | 1987-11-23 | Counting living aquatic animals immersed in water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8727361A GB2212609A (en) | 1987-11-23 | 1987-11-23 | Counting living aquatic animals immersed in water |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8727361D0 GB8727361D0 (en) | 1987-12-23 |
| GB2212609A true GB2212609A (en) | 1989-07-26 |
Family
ID=10627392
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8727361A Withdrawn GB2212609A (en) | 1987-11-23 | 1987-11-23 | Counting living aquatic animals immersed in water |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2212609A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0439023A3 (en) * | 1990-01-23 | 1991-11-06 | Comar, Inc. | Image analysis counting system |
| EP0501639A3 (en) * | 1991-02-28 | 1993-04-28 | Kirby Lester, Inc. | Apparatus and method for counting objects |
| ES2081774A1 (en) * | 1994-08-23 | 1996-03-01 | Cultivos Marinos Del Sur S A | Machine for counting small fish |
| US5692064A (en) * | 1993-11-01 | 1997-11-25 | Hitachi, Ltd. | Method and apparatus for counting underwater objects using an ultrasonic wave |
| DE102007008412B3 (en) * | 2007-01-30 | 2008-07-17 | Fülling, Olaf, Dr. | Method for detection and metering of smaller mammals in burrow system, involves guiding detected animal through compulsory guide placed in pathway system and determining temperature rise caused by body temperature in contact-less manner |
| WO2015112086A1 (en) * | 2014-01-27 | 2015-07-30 | Väderstad-Verken Ab | Device for monitoring feeding of granules, feeding device for such granules and method of installation of such monitoring device |
| LU504832B1 (en) * | 2023-07-28 | 2025-01-28 | Luxembourg Inst Science & Tech List | Device for capturing images of aquatic animals like amphibians, with ballast cavities |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112193378B (en) * | 2020-11-09 | 2024-09-10 | 威海海洋职业学院 | Aquatic product processing ship |
| CN115624008B (en) * | 2022-07-08 | 2023-09-05 | 珠海科艺普检测科技有限公司 | Intelligent detection method for fries of largemouth black weever based on biological information technology |
-
1987
- 1987-11-23 GB GB8727361A patent/GB2212609A/en not_active Withdrawn
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0439023A3 (en) * | 1990-01-23 | 1991-11-06 | Comar, Inc. | Image analysis counting system |
| EP0501639A3 (en) * | 1991-02-28 | 1993-04-28 | Kirby Lester, Inc. | Apparatus and method for counting objects |
| US5692064A (en) * | 1993-11-01 | 1997-11-25 | Hitachi, Ltd. | Method and apparatus for counting underwater objects using an ultrasonic wave |
| ES2081774A1 (en) * | 1994-08-23 | 1996-03-01 | Cultivos Marinos Del Sur S A | Machine for counting small fish |
| DE102007008412B3 (en) * | 2007-01-30 | 2008-07-17 | Fülling, Olaf, Dr. | Method for detection and metering of smaller mammals in burrow system, involves guiding detected animal through compulsory guide placed in pathway system and determining temperature rise caused by body temperature in contact-less manner |
| WO2015112086A1 (en) * | 2014-01-27 | 2015-07-30 | Väderstad-Verken Ab | Device for monitoring feeding of granules, feeding device for such granules and method of installation of such monitoring device |
| LU504832B1 (en) * | 2023-07-28 | 2025-01-28 | Luxembourg Inst Science & Tech List | Device for capturing images of aquatic animals like amphibians, with ballast cavities |
| WO2025026969A1 (en) * | 2023-07-28 | 2025-02-06 | Luxembourg Institute Of Science And Technology (List) | Device for capturing images of aquatic animals like amphibians, with ballast cavities |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8727361D0 (en) | 1987-12-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |