The invention relates to a system and a method for sorting fish during fishing.
Trawl systems employed during fishing normally consist of a trawl and a large trawl bag or several smaller trawl bags. The trawl consists of a funnel which collects the fish and guides the fish backwards to one or more trawl bags which collect the fish. The trawl bags may be equipped with two steel rails which enable them to be mounted on a framework in connection with the trawl, and where each trawl bag can be opened or closed as required. The opening and closing mechanism of the trawl bags is driven by a motor which is controlled from the vessel via a two-way communication link, where one transducer (transmitter/receiver) is located in the ship's hull while a second transducer is located in connection with the framework of the trawl. A steel rail (net profile) is mounted at the top and bottom of the trawl bags. The net profiles are coupled to a release unit and locked in an upper position on the framework. When the net profile is released and moved from an upper to a lower position, a signal will be given when the profile passes a net switch indicating that release has taken place. The signal is transmitted to the vessel via the communication link. In practice it has proved to be difficult to know what kind of fish and the size of the fish that are in the trawl and the trawl bags without pulling the trawl up on deck. Nor is there any exact information on where the fish is located in the sea, or where the fish enters the trawl. In other words it is a case of “fishing in the dark”. An object of the present invention is therefore to provide a system for monitoring and sorting fish during fishing.
The applicant has developed a system for monitoring fish which are on the way into one or more trawl bags in order to work out the kind of fish, number of fish (quantity) and the size of the fish. The system which has been developed employs a part of the above-described trawl system in addition to a monitoring device located in front of the trawl bag, and preferably in front of a sorting grid. A sorting grid can be employed for separating unwanted types of fish—secondary catch, in addition to fish which is too small—small fry. The monitoring device is in communication with the transducer and/or processing equipment located on the vessel or in connection with the trawl. The monitoring device may be in the form of a camera, echo sounder, trawl eye or other devices which permit real time monitoring of the inlet to the trawl bags. By providing such a system, an operator may either give a signal to a device to move one or more of the trawl bags on the framework depending on the amount of fish, kind of fish and size of the fish, or the movement may be performed automatically by means of calculations and on a signal from the processing equipment. In order to avoid unwanted fish, for example with regard to the size or type of fish, filling the trawl, the operator may either give a signal to a device which moves the opening of the trawl bag or the opening may be moved automatically by using the device, with the result that the fish flow right through the trawl and past the trawl bags. Time is thereby saved when the trawl is pulled up to the vessel by minimising the time spent on sorting unwanted fish. The opening where the fish slip through may be anywhere in the framework: at the top, in the middle, at the bottom, on the side or in another suitable area.
The invention comprises a system as described in the independent patent claim 1 and in the independent method claim 7, while embodiments of the invention are described in the dependent patent claims.
The invention relates to a system for sorting fish where the system comprises;
The invention also relates to a method for sorting fish when using a trawl where the method comprises the steps:
The device employed for opening and closing the trawl bags, in addition to movement of the trawl bags to or from a position where the fish can flow on the outside of the trawl bags, may be a motor or any other suitable device for movement which can be controlled via a two-way communication link from the processing unit.
In an embodiment the processing unit may be provided on the surface, while in another embodiment the processing unit may be arranged in connection with the at least one trawl bag.
In another embodiment the at least one monitoring device may be in the form of a camera, echo sounder, trawl eye or any other device which is suitable for monitoring fish. Based on information from the monitoring device, the trawl bags may either be moved automatically or moved manually on a signal from an operator.
In an embodiment the at least one trawl bag may be provided with a set of rails to permit mounting on a framework in connection with the trawl. Having the at least one trawl bag moving on the rail permits unwanted fish to flow on the outside of the at least one trawl bag and prevents the at least one trawl bag from being filled with unwanted fish. The rail may be made of steel or another hard material such as metal, plastic etc.
In an embodiment the system may comprise a sorting grid. At least one of the following sensors may be mounted at the sorting grid: load meter, tensiometer or angle gauge. The sensors measure different parameters for the sorting grid in order to work out the amount of fish at the sorting grid This is done by measuring one or more of the following parameters: the load on the sorting grid, the tension in the sorting grid or, the angle of the sorting grid The sensors can also measure the load, tension and the angle of the net to the trawl near the sorting grid. Based on measured data the amount of fish located at the sorting grid can be calculated.
In an embodiment the sorting grid may be arranged in front of the framework. Another embodiment may be envisaged where no framework is employed for the trawl bags but there is only a sorting grid in front of the trawl bags. In this embodiment openings will be provided in connection with the sorting grid in order to release unwanted fish.
The term “inflow area” in connection with the trawl should be understood to refer to the area in front of the trawl bags.
The invention is described herein in non-limiting embodiments. A person skilled in the art will appreciate that changes and modifications may be made which are within the scope of the invention as will be apparent in the attached claims.
Number | Date | Country | Kind |
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20111284 | Sep 2011 | NO | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/IB2012/055023 | 9/21/2012 | WO | 00 | 3/21/2014 |