Patent Application
20210176971
Many species of fish exhibit seasonal migrations when large numbers of individuals migrate through streams and rivers. In many cases, these migrating fish are attempting to access their breeding grounds. In the case of native fish, management efforts often aim to facilitate these migrations, especially if migration routes are blocked by dams or other physical barriers. In the case of invasive fish, the goal is to block these migrations and remove the fish.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.
A system includes a fish stunner configured to stun fish within a stunning zone of a waterway and a conveyor with a portion of the conveyor located below a waterline of the waterway and a second portion of the conveyor located above the waterline such that fish that have been stunned reach the conveyor and are lifted out of the water by the conveyor. In accordance with a further embodiment, a method includes activating a fish stunner in a waterway to produce stunned and drifting fish and directing the stunned and drifting fish onto a conveyor that is at least partially in the waterway. The conveyor is then used to lift stunned fish out of the waterway.
In accordance with a still further embodiment, a system includes a fish holding area and a stunning device located in a waterway and a conveyor located relative to the stunning device such that stunned fish move with a current onto the conveyor.
In accordance with a still further embodiment, a fence for a waterway includes first and second lateral supports, each having a plurality of holes, and a plurality of posts. Each post passes through a respective hole of the plurality of holes of the first lateral support and a respective hole of the plurality of holes of the second lateral support such that each post moves through the post's respective holes independently of other posts of the plurality of posts.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Embodiments described below provide an efficient means for removing migrating fish from a waterway without killing the fish.
System 100 includes a barrier 114 positioned in river 102 along a direction 109 at an angle θ relative to the flow direction 108 of waterway 102 where θ is generally greater than 90° and less than 180°. Migrating fish generally swim against flow direction 108. When a migrating fish reaches barrier 114, the fish is unable to swim through barrier 114 and as a result, the fish's efforts to continue moving upstream against flow direction 108 cause the fish to move upstream along barrier 114 as shown generally by fish paths 130, 132 and 134.
In accordance with some embodiments, barrier 114 is a physical fence made for example from poly-vinyl chloride (PVC) posts or stakes that are connected together by lateral supports to provide a space between each post that allows water to flow through the posts but prevents migrating fish from passing between the posts. In other embodiments, barrier 114 is an electrical barrier or a guidance/deterrence system consisting of one or more suspended electrodes along the barrier. In other embodiments, barrier 114 could be an electric barrier placed on the bottom of the stream. In other embodiments, barrier 114 is an acoustic or light guidance/deterrence system. In
Barrier 114 leads the migrating fish to a gate 120 in a fence 118 that defines a holding area 116. Fence 118 includes a holding portion 140 that defines an upstream portion of holding area 116. After migrating fish pass through gate 120, they continue to swim upstream until they are stopped by holding portion 140 of fence 118. The fish continue to swim against the current at this position and thus remain in the upstream portion of holding area 116. In accordance with one embodiment, fence 118 is a physical barrier constructed of spaced-apart posts that extend from the bottom of the waterway to above the waterline. The spaced-apart posts are connected together by lateral supports so that there is enough space between the posts to allow the water current to pass through fence 118 while preventing the migrating fish from passing through fence 118. In accordance with some embodiments, fence 118 is made of PVC.
Holding area 116 includes a crowding device 122, a fish stunning device 124, and a conveyor 126. Fish stunning device 124 is located downstream of crowding device 122 and at least a portion of conveyor 126 is located relative to stunning device 124 such that stunned fish are carried by a current to conveyor 126. In system 100, crowding device 122 consists of rows of electrodes, such as rows 160, 162, 164, 166, 168 and 170. The rows of electrodes are capable of being independently energized to generate an electric field between the electrodes in a row-by-row fashion. By sequentially energizing the rows of electrodes starting from the furthest upstream row 160 and ending with the furthest downstream row 170, it is possible to direct the fish downstream thereby crowding the fish around the stunning device 124. Specifically, when a row of electrodes is activated, fish that are within the electric field generated by the electrodes will be irritated by the electric field and will swim downstream until they are outside of the electric field. This will place the fish in the area around the next row of electrodes, which are then activated thereby causing the fish to swim further downstream. When a row of electrodes is activated, it may remain activated so that eventually all of the rows of electrodes are energized at the same time or the row may be deactivated a short time after the row downstream from the row is energized so that only one or two rows of electrodes are energized at the same time.
To prevent the fish from exiting holding area 116 during this crowding, gate 120 is closed before crowding device 122 is activated. In accordance with one embodiment, gate 120 consists of two electrodes 172 and 174 that are energized to close gate 120 and are de-energized to open gate 120. In other embodiments, gate 120 can be a physical movable gate that can move vertically out of the waterway, pivot laterally on a hinge, or slide laterally within the waterway, for example.
Stunning device 124, also referred to as fish stunner 124, consists of two or more electrodes such as electrodes 180 and 182 that are de-energized until fish have been crowded around stunning device 124 by crowding device 122 and then are energized to generate an electric field that stuns fish in a stunning zone 184. Although fixed electrodes are shown in the Figures, stunning device 124 can also be implemented using portable electrodes such as a backpack electrofisher or a floating vessel (e.g. boat) with electrodes. In accordance with one embodiment, stunning zone 184 is a volume of water that extends from the top surface of the water to the bottom of the waterway and that extends both upstream and downstream of electrodes 180 and 182. In accordance with one embodiment, at least a portion of conveyor 126 is located relative to the stunning zone 184 such that stunned fish will drift with a current from stunning zone 184 to conveyor 126. In accordance with one embodiment, electrodes 180 and 182 only need to be momentarily energized in order to stun the fish and once the fish are stunned, the electrodes 180 and 182 are turned off. Once stunned, the fish are temporarily unable to swim but are still alive. Because they are unable to swim, the stunned fish drift with the current, which can be the natural current of waterway 102 or an artificial current generated by one or more pumps.
A stunned fish cannot be controlled using electrodes because the fish is unable to swim away from an electric field. In order to ensure that each stunned fish comes into contact with conveyor 126, a set of physical guides are placed in the waterway that extend from the sides and bottom of conveyor 126 in an upstream direction past stunning device 124. Such physical guides physically restrain where the fish can drift to as opposed to electric field guides that use electric fields to guide the fish. In some embodiments, the physical guides extending from the sides of conveyor 126 are constructed of spaced-apart posts that extend from the bottom of the waterway to above the waterline and the guide at the bottom of the conveyor is a board or a metal surface. The spaced-apart posts are connected together by lateral supports that maintain the spacing between the posts to allow the water current to flow through the physical guides while preventing fish larger than a threshold size from passing through the guides. The spacing between the posts is selected to prevent the targeted migrating fish from passing through the guides after the fish have been stunned while allowing smaller fish to pass through the guides. In the embodiment of
Motor 216 is rotatably engaged with belt 210 such that when motor 216 is on and rotating, motor 216 rotates belt 210 around frame 212 in a direction 214. Belt 210 includes a plurality of supports, such as supports 218 and 220, which extend away from the surface of belt 210 so as to provide a surface for supporting fish as they are conveyed from waterway 102 to a top end 234 of conveyor 126. Belt 210 has a width 194 that extends from side 190 to side 192 between guide portions 142 and 144 such that any gap between belt 210 and guide portions 142 and 144 is small enough to prevent a stunned fish from passing through the gap. As shown in
As belt 210 rotates around conveyor 126, drifting stunned fish in waterway 102 contact belt 210 and the supports of belt 210, such as supports 218 and 220, and are transported along conveyor 126 by belt 210 to end 234 of conveyor 126. When the fish reach end 234, they drop from end 234 onto a lateral conveyor or slide 240, which conveys the stunned fish to a receptacle or transport vehicle 242 located on the riverbank. The stunned fish can then be transported to another part of the waterway or can be sorted to remove invasive species before returning non-invasive species to the water.
In
System 500 includes a barrier 514 positioned in river 102 at an angle θ relative to the flow direction 108 of waterway 102 where θ is generally less than 90. When a migrating fish reaches barrier 514, the fish is unable to swim through barrier 514 and as a result, the fish's efforts to continue moving downstream cause the fish to move downstream along barrier 514 as shown generally by fish paths 530, 532 and 534.
In accordance with some embodiments, barrier 514 is a physical fence made for example from poly-vinyl chloride (PVC) posts or stakes that are connected together by lateral supports to provide a space between each post that allows water to flow through the posts but prevents migrating fish from passing between the posts. In other embodiments, barrier 514 is an electrical barrier or a guidance/deterrence system consisting of one or more suspended electrodes along the barrier. In other embodiments, barrier 514 could be an electric barrier placed on the bottom of the stream. In other embodiments, barrier 514 is an acoustic or light guidance/deterrence system. In
Barrier 514 leads the migrating fish to a gate 520 in a fence 518 that defines a holding area 516. In accordance with one embodiment, fence 518 is a physical barrier constructed of spaced-apart posts that extend from the bottom of the waterway to above the waterline. The spaced-apart posts are connected together by lateral supports so that there is enough space between the posts to allow the water current to pass through fence 518 while preventing the migrating fish from passing through fence 518. In accordance with some embodiments, fence 518 is made of PVC.
Holding area 516 includes a crowding device 522, a fish stunning device 524, and conveyor 526. Fish stunning device 524 is located downstream of crowding device 522 and at least a portion of conveyor 526 is located downstream from fish stunning device 524. In system 500, crowding device 522 consists of rows of electrodes, such as rows 560, 562, 564, 566, 568 and 570. The rows of electrodes are capable of being independently energized to generate an electric field between the electrodes in a row-by-row fashion. By sequentially energizing the rows of electrodes starting from the furthest upstream row 560 and ending with the furthest downstream row 570, it is possible to direct the fish downstream thereby crowding the fish around stunning device 524. Specifically, when a row of electrodes is activated, fish that are within the electric field generated by the electrodes will be irritated by the electric field and will swim downstream until they are outside of the electric field. This will place the fish in the area around the next row of electrodes, which are then activated thereby causing the fish to swim further downstream. When a row of electrodes is activated, it may remain activated so that eventually all of the rows of electrodes are energized at the same time or the row may be deactivated a short time after the row downstream from the row is energized so that only one or two rows of electrodes are energized at the same time.
To prevent the fish from exiting holding area 516 during this crowding, gate 520 is closed before crowding device 522 is activated. In accordance with one embodiment, gate 520 consists of two electrodes that are energized to close gate 520 and are de-energized to open gate 520. In other embodiments, gate 520 can be a physical movable gate that can move vertically out of the waterway, pivot laterally on a hinge, or slide laterally within the waterway, for example.
Stunning device 524, also referred to as fish stunner 524, consists of at least two electrodes, such as electrodes 580 and 582, that are de-energized until fish have been crowded around stunning device 524 by crowding device 522 and then are energized to generate an electric field that stuns fish in a stunning zone 584. In accordance with one embodiment, stunning zone 584 is a volume of water that extends from the top surface of the water to the bottom of the waterway and that extends both upstream and downstream of the electrodes that form fish stunner 524. In accordance with one embodiment, at least a portion of conveyor 526 is located downstream from stunning zone 584. In accordance with one embodiment, the electrodes of fish stunner 524 only need to be momentarily energized in order to stun the fish and once the fish are stunned, the electrodes are turned off. Once stunned, the fish are temporarily unable to swim but are still alive. Because they are unable to swim, the stunned fish drift with the current of the waterway, which can be the natural current of the waterway or an artificially generated current formed by one or more pumps.
A stunned fish cannot be controlled using electrodes because the fish is unable to swim away from an electric field. In order to ensure that each stunned fish comes into contact with conveyor 526, a set of physical guides are placed in the waterway that extend from the sides and bottom of conveyor 526 in an upstream direction past stunning device 524. Such physical guides physically restrain where the fish can drift to as opposed to electric field guides that use electric fields to guide the fish. In some embodiments, the physical guides are constructed of spaced-apart posts that extend from the bottom of the waterway to above the waterline. The spaced-apart posts are connected together by lateral supports that maintain the spacing between the posts to allow the water current to flow through the physical guides while preventing fish larger than a threshold size from passing through the guides. The spacing between the posts is selected to prevent the targeted migrating fish from passing through the guides after the fish have been stunned while allowing smaller fish to pass through the guides.
Conveyor 526 has the same structure and operates in the same manner as conveyor 126. After fish stunner 524 has been activated, a motor on conveyor 526 is turned on causing a belt to rotate around conveyor 526. Drifting stunned fish in waterway 102 contact the belt and supports of the belt and are transported along conveyor 526 to an end of conveyor 526. When the fish reach the end of conveyor 526, they drop from the end onto a lateral conveyor or slide 540, which conveys the stunned fish to a receptacle or transport vehicle 542 located on the riverbank. The stunned fish can then be transported to another part of the waterway or can be sorted to remove invasive species before returning non-invasive species to the water.
During installation, sections of the fence are first formed by inserting hollow posts in each of the holes of the two lateral supports of the section with the exception of the holes at the ends of the lateral supports. In accordance with one embodiment, the holes of the lateral supports are sized relative to the hollow posts such that the hollow posts are held in place in the lateral supports by friction. A section of the fence is then taken to its desired position in the waterway and two or more of the hollow posts in the section are driven into the bottom 202 of the waterway so that they become embedded in the waterway as indicated by the dotted lines of
Because of the spacing between the hollow posts, water can flow between the posts while the sections are being moved into position. This makes it easier to move the sections than if the sections were made of solid walls. In addition, because the hollow posts can be independently driven into bottom 202, each post can be driven a different amount so as to accommodate unevenness in bottom 202. In addition, because the hollow posts can be independently driven into bottom 202, if scouring occurs underneath any of the posts, these posts can be driven further into the sediment without the need to readjust the entire panel, which would be the case of posts were attached to lateral supports by means other than friction. This makes installation and maintenance much more practical than if the posts were attached to lateral supports by means other than friction.
As shown in the top view of
Although elements have been shown or described as separate embodiments above, portions of each embodiment may be combined with all or part of other embodiments described above.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms for implementing the claims.
The present application is based on and claims the benefit of U.S. provisional patent application Ser. No. 62/948,501, filed Dec. 16, 2019, the content of which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62948501 | Dec 2019 | US |
