Apparatus and method for collection of aquatic animals

Abstract

Apparatus 10 for collecting submerged objects from an aquaculture enclosure. The apparatus 10 comprises a porous container 12 provided with an entrance 14 for receiving objects, a guide member 16 for

Description

Technical Field The present disclosure relates to an apparatus and method for collecting submerged objects from within a body of water and, particularly, though not exclusively, to a remotely operated vehicle [ROV] comprising such apparatus for collecting dead, diseased, or dying fish from within an aquaculture enclosure. Background Aquaculture involves the controlled cultivation of fish or other aquatic animals within enclosures such as cages or nets submerged in a sea or an inland waterway. Over time, dead fish tend to accumulate at the bottom of aquaculture enclosures. This may pose numerous problems such as the blocking of fresh water flow, the spreading of disease or hygiene issues among surviving fish and other aquatic animals, and the potential attraction of predators that may cause damage to the enclosure. In order to minimise the aforementioned problems it is necessary to regularly remove dead fish from aquaculture enclosures. In some cases this has involved human divers being deployed into enclosures to manually remove dead fish. This is dangerous and laborious work and often prohibitively expensive such that removal of dead fish may not be performed as regularly as is needed. It is also known to deploy remotely operated vehicles (ROVs) into enclosures to collect dead fish. ROVs are provided with pumping systems to lift and move dead fish into a container for removal at the surface. However, pumping systems introduce additional capital expense and maintenance costs to the ROV, and require additional energy to operate. Accordingly, there is a need for an alternative apparatus which overcomes, or at least ameliorates, one or more of the aforementioned problems. Summary According to a first aspect of the present invention there is provided an apparatus for collecting submerged objects from within a body of water, the device comprising: a porous container provided with an container entrance for receiving said objects; and a guide member for guiding said objects towards the container entrance; wherein the guide member comprises a conveyor provided with a conveying surface for assisting inward movement of said objects through the container entrance. It will be appreciated that the term "object” encompasses both inanimate objects and / or aquatic animals (whether alive or dead). The body of water may be naturally occurring body of fresh or salt water; or any body of water comprising an artificially enclosed area, such as an aquaculture enclosure. Significantly, movement of the conveying surface of the guide member obviates the need for any kind of pump system for creating a fluid flow inwardly through the container entrance. This is advantageous because pump systems introduce additional capital expense and maintenance costs, and require additional energy to operate. In its simplest form the conveyor may take the form of a single roller, where the surface of the roller itself defines the conveying surface. In other embodiments, the conveyor may take the form of a plurality of rollers. The plurality of rollers may be connected via a belt which defines the conveying surface. Optionally, the guide member comprises a guide arm pivotably attachable to the porous container about a pivot axis for adjusting a conveying angle of said conveying surface. For example, the guide arm may extend substantially parallel to an axis extending through the centre of the container entrance on a forward-facing side of the apparatus in use such that the conveying angle is neutral or zero. Alternatively, the end of the guide arm most distal to the container entrance may be spaced further from the axis than the end of the guide arm most proximal to the container entrance such that the conveying angle relative to the axis is positive. Alternatively, the end of the guide arm most distal to the container entrance may be spaced closer to the axis than the end of the guide arm most proximal to the container entrance such that the conveying angle relative to the axis is negative. Optionally, the pivot axis is located proximate the container entrance. It will be appreciated that such a positioning of the pivot axis helps to direct the objects to be collected into the container opening irrespective of the conveying angle. Optionally, the pivot axis extends substantially vertically. Alternatively, the pivot axis extends substantially horizontally. It will be appreciated that the terms vertical and horizontal are relative to a base of the apparatus upon which it supported when out of the water. In some embodiments, the pivot axes may extend at an intermediate angle between the horizontal and vertical. Optionally, the guide member comprises two opposed guide arms each being pivotable between: (i) an open position wherein the ends of the guide members distal to the pivot axis are at their maximum separation; (ii) an object-receiving position wherein the ends of the guide members distal to the pivot axis are at an intermediate separation; and (hi)   a closed position wherein the ends of the guide members distal to the pivot axis are at their minimum separation. It will be appreciated that an opposed pair of guide arms (when in their open position) creates a funnel which converges about the container entrance to guide objects therethrough. Optionally, the conveyor is automatically disabled when the two opposed guide arms are pivoted to their closed position. It will be appreciated that this feature reduces the energy consumption when the apparatus is not being used to collect objects. Optionally, the, or each, conveyor is provided with an endless conveying surface. Optionally, the, or each, conveying surface is provided with a surface texture intended to enhance its frictional engagement with an object to be collected. Optionally, the, or each, conveying surface is provided with a plurality of protrusions to enhance its engagement with an object to be collected. It will be appreciated that the protrusions need not physically engage the object,. In some embodiments, the protrusions impart a fluid flow in their vicinity to entrain objects within a fluid flow and draw them inwards towards, and through, the container entrance. Other technical characteristics of the conveying surface may be matched to the types, sizes, and surface characteristics of the objects to be collected. Optionally, one or more shrouds are attached to the porous container and said shroud(s) at least partially covers the, or each, conveyor. Optionally, a respective shroud is provided for each respective conveyor. It will be appreciated that the shroud(s) protects the conveyor [s] and in particular avoids objects coming into contact with the outermost portions of the conveyor(s) as they rotate / return to their object-engaging positions on the guide arm(s). Optionally, the, or each, shroud comprises a grill over the, or each, conveying surfacers]. The grill may comprise a series of spaced bars. A maximum spacing between the bars may be smaller than the typical size of the objects to be collected. Optionally, the, or each, shroud comprises a continuous shroud portion on an outermost side of the conveyors. In use, the continuous shroud portion prevents any contact between the outermost side of the conveyors and the surrounding environment. The grill may cover the conveying surface. The shroud may encase the conveyor. The grill may be in front of the conveying surface. Optionally, the or each shroud may be connected to a respective one of the guide arm(s). The shroud(s) may therefore move with the guide arm(s) in the manner described above. Optionally, the porous container comprises a wall comprising a mesh with a maximum opening size smaller than the typical size of the objects to be collected. It will be appreciated that the technical characteristics of the mesh may be matched to the types and sizes of the objects to be collected. This may be particularly important when the objects are smaller, young aquatic animals which are not intended to be collected. The mesh may be provided on a container in the form of a cage, netting, or a bag. According to a second aspect of the present invention there is provided a remotely operated vehicle (ROV) comprising the apparatus of any preceding claim for collecting submerged objects in the form of dead, diseased, or dying fish from within an aquaculture enclosure. It will be appreciated that the ROV may be retrofitted to carry the apparatus of the first aspect; or it may be purpose-built to comprise the apparatus of the first aspect. Optionally, the remotely operated vehicle (ROV) comprises two opposed conveying surfaces for assisting inward movement of dead, diseased, or dying fish into the porous container. Optionally, said two opposed conveying surfaces are convergeable towards, or away from, the container entrance. According to a third aspect of the present invention there is provided a method of collecting dead, diseased, or dying fish from within an aquaculture enclosure by deploying a remotely operated vehicle (ROV) comprising the apparatus of the first aspect into the aquaculture enclosure; manoeuvring the guide member proximate a target fish; and using the, or each, conveyor to assist inward movement of said target fish into the porous container of the apparatus. Advantageously, movement of the conveying surface (s) of the guide member obviates the need for any kind of pump system for creating a fluid flow inwardly through the container entrance. Accordingly, the associated capital expense and maintenance costs are eliminated, and the energy required to operate the apparatus to collect fish is vastly reduced. Optionally, two opposed conveying surfaces of the guide member are pivotable to permit adjustment of their conveying angles between: (i) a closed position used to retain fish within the porous container when repositioning the remotely operated vehicle (ROV) within the aquaculture enclosure; (ii) a fish-receiving position used when collecting dead, diseased, or dying fish; and (hi) an open position used when emptying the contents of the porous container. It will be appreciated that the various positions of the conveying surfaces allow them to fulfil different functions at different parts of the fish collection process. Further features and advantages of the first, second, and third aspects of the present disclosure will become apparent from the claims and the following description. Brief Description of Drawings Embodiments of the present disclosure will now be described by way of example only, with reference to the following diagrams, in which:- Fig. 1 shows a schematic representation of an apparatus according to the present invention with opposed guide arms and their associated conveyors in an open or object-receiving position; Fig. 2 shows a schematic representation of the apparatus of Fig. 1 with its opposed guide arms and their associated conveyors in a closed position; Figs 3A-C show partial schematic representations of the opposed guide arms and their associated conveyors pivoted into three different positions; Fig. 4 shows a schematic representation of an alternative embodiment of apparatus according to the present invention with opposed guide arms and an alternative vertical conveyor arrangement in an open or object-receiving position; Fig. 5 shows a schematic representation of a further alternative apparatus according to the present invention with opposed guide arms and an alternative horizonal conveyor arrangement in an open or object-receiving position; Figs. 6A-C show an apparatus according to the present invention (without its container) with opposed guide arms and their associated conveyors in different positions; and Fig. 7 shows a perspective view of an ROV with opposed shrouded guide arms and their associated conveyors in an open or object-receiving position. Detailed Description Fig. 1 shows an apparatus 10 comprising a container 12 for storing collected objects, e.g. dead fish. Though not shown in the figures, the container 12 is porous such that water and possibly aquatic animals and organisms which are smaller than those targeted for collection are able to pass through or escape from the porous container 12. Although the porous container is represented in the schematic drawings as being cuboidal in shape with a planar base 12b, a planar top 12t, and four planar sides 12s, it will be appreciated that other shapes are not precluded. An entrance 14 (best shown in Fig. 6C) is provided on a forward-facing side 12s of the container 12 through which dead fish must pass to enter the container 12. A guide member in the form of two opposed guide arms 16 is attached to the forward-facing side 12s of the container 12 adjacent the entrance 14. Each guide arm 16 is pivotably attached to the forward-facing side 12s of the container 12 via a vertical pivot axis 19 (see Figs. 3A-C). Each guide arm 16 is provided with an endless conveyor 18. The conveyors 18 each rotate in opposite directions about conveyor pulleys 2 0 to thus ensure that the conveying surfaces 22 which face one another each move towards the entrance 14 in the director of arrow A in Fig. 1. Each conveying surface 22 is provided with a plurality of protrusions in the form of flaps or cleats 24 for enhancing frictional engagement with an object or fish to be collected. NB: for the sake of clarity, in Figs. 1 and 2, the cleats 24 are shown only on the inwardly facing conveyor surfaces 22. As best shown in the cut-away portions of Figs. 3A and 3B, the cleats 24 are in fact provided along the entire length of each endless conveyor 18. A cover or shroud 26 is attached to the forward-facing side 12s of the container 12, surrounding the entrance 14, for protecting a major portion of each guide arm 16. In particular, as the conveying surfaces 22 travel away from the entrance 14 in a direction opposite to that of arrow A in Fig. 1, the shroud 26 prevents those portions of the conveyor 18 from contacting fish or colliding with other objects as the apparatus 10 moves around in the water. The shroud may be viewed as defining an extension to the entrance 14 which extends forward from a front side 12s of the container 12. In Fig. 1, each guide arm 16 is in an open position either for enabling the container 12 to be emptied of its contents, or for enable objects such as dead fish to be received into the container 12. As will be described further below, the angular position of each guide arm 16 may be adjusted dependent on factors such as the expected dimensions of the target objects or fish; and the operational status of the apparatus, e.g. whether it is in a collection state; a repositioning state; or an emptying state. Fig. 2 shows the guide arms 16 in a position whereby they have been pivoted about their pivot axes (see Figs. 3A-C) such that their ends 18d most distal to the entrance 14 are moved towards one another. In doing so, the guide arms 16 effectively close off the entrance 14 by eliminating are minimising the distance between the distal ends 18d . When in such a closed position, the conveyors 18 be automatically deactivated. A closed position of the guide arms 16 may be used when the container 12 is full and / or during the process of repositioning the apparatus within a body of water when collection of objects or fish is not occurring. Fig. 3A shows a pair of guide arms 16 in isolation from the remainder of the apparatus 10. Each guide arm is connectable to the housing 12 about a pivot axis 19 attachable to the forward-facing side 12s (not shown) of the container 12 (not shown). An endless conveyor 18 in the form of a belt is rotatable (in the directions of arrows B) about a proximal pulley 20p and a distal pulley 20d (relative to the container entrance 14) provided on each guide arm 16. In the example embodiment of Figs 3A-C, the proximal pulleys 20p are each shown to be coincident with the pivot axes 19, but this need not be the case. The cleats 24 extend generally perpendicularly away from the conveyor belt surfaces 22 during their travel from the distal pulley 20d to the proximal pulley 20p. During the return part of their rotation between the proximal pulley 2 Op and the distal pulley 20d, the cleats enter a channel 25 of the guide arm 16 which causes them to flex towards the conveyor belt surface 22 until they exit the channel proximate the distal pulley 20d. Whilst in the open position shown in Fig. 3A, the guide arms 16 are at their maximum separation and hence ready to receive objects or fish to be collected (or in a position to facilitate easy emptying of the container 12 via the entrance 14). Whilst in the open position shown in Fig. 3B, the guide arms 16 are at an intermediate separation and ready to receive objects or fish to be collected. It will be appreciated that the separation of the guide arms 16, and hence the degree of opening, can be controlled dependent on factors such as the dimensions of the target objects or fish to be collected. Whilst in the closed position shown in Fig. 3C, the guide arms 16 are at their minimum separation and unable to receive objects or fish of any significant size. As mentioned above, a closed position of the guide arms 16 may be used when the container 12 is full and / or during the process of repositioning the apparatus within a body of water when collection of objects or fish is not occurring. The conveyors 18 may be automatically disabled when the guide arms 16 are in their closed position. Fig. 4 shows at alternative embodiment whereby the guide arms 16 comprise endless conveyors 18 having no flaps or cleats for enhancing frictional engagement with an object or fish to be collected. Instead, the conveying surfaces 22 is provided with a roughened surface texture intended to enhance its frictional engagement with an object or fish to be collected. The pivot axes (not shown) in Fig. 4 extend at an intermediate angle such that the lowermost part of each distal end 18d of each conveyor 18 is lower than the correspondingly lowermost part of each proximal end (not shown) of each conveyor. Accordingly, the guide arms 16 and their associated conveyors are directed downwardly as can be appreciated via a comparison with the equivalent features of Figs. 1 and 2. The shroud 26 in Fig. 4 is adapted accordingly by reducing the distance by which its lowermost surface 261 extends away from the forward-facing side 12s of the container 12 relative to its uppermost surface 26u. This arrangement may be favoured when objects or fish are to be collected from below, for example, from the base of an aquaculture enclosure. Fig. 5 shows a yet further alternative embodiment whereby the pivot axes (not shown) extend horizontally. Accordingly, the guide arms 16 and their associated conveyors 18 are located one above the other rather than in a side-by-side relationship as can be appreciated via a comparison with the equivalent features of Fig. 4. Fig. 6A shows a yet further alternative embodiment whereby the distal end of the shroud 26 is larger than its proximal end proximate the entrance 14 (best seen in Fig. 6C). Accordingly, the side surfaces 26s of the shroud 26 each diverge away from an axis X-X extending centrally through the entrance 14. This arrangement of the shroud 16 enables a wider angle of adjustment of the guide arms 16 and their associated conveyors 18. From a comparison between Figs. 1 and 6A (or 6C) it will be appreciated that the conveyors 18 of Fig. 6A (or 6C) have a wider separation at the distal ends 18d than they do at their proximal ends, i.e. the separation between the conveying surfaces 22 becomes progressively narrower towards the container entrance 14. In use, the apparatus of the various embodiments described above may carried by a remotely-operated vehicle [ROV] which can be propelled and manoeuvred in three-dimensions within a body of water to a target location. The ROV may be purpose-built, or it may be retrofitted to include the apparatus of the present invention. The ROV may be tethered to a control centre on the surface via an umbilical or it may be wirelessly controlled. Ancillary apparatus such as video cameras may be provided onboard the ROV to assist with manual operation. Alternatively, the ROV may be fully automated. In use, the ROV is manoeuvred into a position proximate a target object or fish and its guide arms 16 moved into an open position. As the ROV approached objects or fish to be collected the conveyors 18 are activated and physically engage the fish to assist their inward movement into the onboard container 12. Advantageously, assisted inward movement of objects or fish is provided without any need for pumping apparatus to create a fluid flow through the container entrance 14. This reduces cost, complexity and energy use. Once the container 12 is full or the collection process is otherwise completed, the guide arms 16 are pivoted to a closed position to retain collected objects or fish in the container 12 until the ROV is re-positioned or removed to the surface for emptying. An ROV 110 is shown in Fig. 7, in which guide arms 116 each have a respective shroud 150. The ROV in Fig. 7 is in an open or object-receiving position. In this embodiment, the protrusions impart a fluid flow in their vicinity to entrain objects within a fluid flow and draw them inwards towards, and through, the container entrance. Shrouds 150 are attached to the porous container 112 and each of said shrouds cover a respective conveyor 118. The shrouds 150 protect the conveyors 118. The shrouds 150 comprise a continuous shroud portion on an outermost side of the conveyors to prevent any contact between an outermost side of the conveyors and the surrounding environment. Each shroud 150 comprises a grill portion on an inner side of the conveyors. Each grill enclosing its respective conveying surface within the respective shroud. The grill comprises a series of spaced bars and a maximum spacing between the bars is smaller than the typical size of the objects to be collected. This prevents the objects from contacting the conveying surfaces, thereby protecting the conveying surfaces, but allows movement of the ocnveyors to generate flow of water on an inner side of the conveyors. The porous container 112 comprises a wall comprising a mesh with a maximum opening size smaller than the typical size of the objects to be collected. Although particular embodiments of the disclosure have been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the scope of the appended claims. It is contemplated by the inventors that various substitutions, alterations, and modifications may be made to the invention without departing from the scope of the invention as defined by the claims. For example, though the illustrated embodiments all employ an endless conveyor belt, other conveying apparatus may be used such as a screw conveyor. Similarly, though the illustrated embodiments all employ two guide arms and two associated conveyor belts, other versions of the apparatus may include more than two sets of guide arms and conveyors. For example, a combination of the features of the embodiments in Figs. 4 and 5 would increase the surface area of conveyor belts to engage target objects or fish and improve the collection efficiency of the apparatus.

Claims

1. An apparatus for collecting submerged objects from within a body of water, the device comprising:a porous container provided with an container entrance for receiving said objects; anda guide member for guiding said objects towards the container entrance; wherein the guide member comprises a conveyor provided with a conveying surface for assisting inward movement of said objects through the container entrance.

2. An apparatus according to claim 1, wherein the guide member comprises a guide arm pivotably attachable to the porous container about a pivot axis for adjusting a conveying angle of said conveying surface.

3. An apparatus according to claim 2, wherein the pivot axis is located proximate the container entrance.

4. An apparatus according to claim 2 or 3, wherein the pivot axis extends substantially vertically.

5. An apparatus according to claim 2 or 3, wherein the pivot axis extends substantially horizontally.

6. An apparatus according to any of claims 2 to 5, wherein the guide member comprises two opposed guide arms each being pivotable between:(i) an open position wherein the ends of the guide members distal to the pivot axis are at their maximum separation;(ii) an object-receiving position wherein the ends of the guide members distal to the pivot axis are at an intermediate separation; and(hi) a closed position wherein the ends of the guide members distal to the pivot axis are at their minimum separation.

7. An apparatus according to claim 6, wherein the conveyor is automatically disabled when the two opposed guide arms are pivoted to their closed position.

8. An apparatus according to any preceding claim, wherein the, or each, conveyor is provided with an endless conveying surface.

9. An apparatus according to any preceding claim, wherein the, or each, conveying surface is provided with a surface texture intended to enhance its frictional engagement with an object to be collected.

10. An apparatus according to any preceding claim, wherein the, or each, conveying surface is provided with a plurality of protrusions to enhance its engagement with an object to be collected.

11. An apparatus according to any preceding claim, wherein a shroud is provided for each respective conveyor, the shroud(s) being attached to the porous container and each shroud at least partially covers the, respective conveyor, wherein each shroud comprises a grill over the conveying surface of the respective conveyor.

12. An apparatus according to any preceding claim, wherein the porous container comprises a wall comprising a mesh with a maximum opening size smaller than the typical size of the objects to be collected.

13. A remotely operated vehicle [ROV] comprising the apparatus of any preceding claim for collecting submerged objects in the form of dead, diseased, or dying fish from within an aquaculture enclosure.

14. A remotely operated vehicle [ROV] according to claim 13, comprising two opposed conveying surfaces for assisting inward movement of dead, diseased, or dying fish into the porous container.

15. A remotely operated vehicle (ROV) according to claim 14, wherein said two opposed conveying surfaces are convergeable towards, or away from, the container entrance.

16. A method of collecting dead, diseased, or dying fish from within an aquaculture enclosure by deploying a remotely operated vehicle [ROV] comprising the apparatus of any of claims 1 to 12 into the aquaculture enclosure; manoeuvring the guide member proximate a target fish; and using the, or each, conveyor to assist inward movement of said target fish into the porous container of the apparatus.

17. A method of collecting dead, diseased, or dying fish according to claim 16, wherein two opposed conveying surfaces of the guide member are pivotable to permit adjustment of their conveying angles between:(i) a closed position used to retain fish within the porous container when repositioning the remotely operated vehicle [ROV] within the aquaculture enclosure;(ii) a fish-receiving position used when collecting dead, diseased, or dying fish; and (hi)   an open position used when emptying the contents of the porous container.

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