The present disclosure discloses an unmanned aerial vehicle (UAV), comprising a housing having a top part and a bottom part, a plurality of arms arranged on the top part, each arm having a motor and an airscrew, a battery unit arranged within the housing, a processor arranged within the housing, a sonar unit having a wire connected thereto, and a positioning unit detachably mounted within a mounting groove recessed from the bottom part, wherein the positioning unit is connected to the wire and configured to retract or release the wire. An UAV readily configured for fishing can be provided by embodiments of the present disclosure.

A continuous trawl fishing method includes: by dragging a fishing net in water through a vessel, carrying out trawling operation so that catches to be fished enter a cod-end of a fishing net tail; then tractioning and moving the cod-end so that a sucking fish tube of a vacuum sucking fish pump reaches into the cod-end; and a tube mouth of the sucking fish tube contacting the catches in the cod-end to run the vacuum sucking fish pump to suck the catches from the cod-end into the collection tank through the sucking fish tube, and the catches in the collection tank being then transferred and frozen or directly processed. The fished catches of the present invention are obviously improved in indicators such as the stiffness time and the number of the first-grade fresh fish and so on. The histamine content is obviously reduced and the catch quality is improved.

A continuous trawl fishing method includes: by dragging a fishing net in water through a vessel, carrying out trawling operation so that catches to be fished enter a cod-end of a fishing net tail; then tractioning and moving the cod-end so that a sucking fish tube of a vacuum sucking fish pump reaches into the cod-end; and a tube mouth of the sucking fish tube contacting the catches in the cod-end to run the vacuum sucking fish pump to suck the catches from the cod-end into the collection tank through the sucking fish tube, and the catches in the collection tank being then transferred and frozen or directly processed. The fished catches of the present invention are obviously improved in indicators such as the stiffness time and the number of the first-grade fresh fish and so on. The histamine content is obviously reduced and the catch quality is improved.

The present invention is a fish passage system for use at dams. It may incorporate one or more reversible pump-turbines for controlling and generating power from downstream flow of water and fish and for pumping water and fish upstream. For low head embodiments the system may use water stored at above headwater elevation in lieu of a reversible pump turbine for moving fish and water from tailwater to headwater.

A method for taking fish up from a body of water comprising the steps of providing a duct (14) having a lower open end below the water surface and an upper open end arranged at a floating working platform (5) above sea level; introducing water into the duct (14) from the upper open end to give a water stream from the upper open end of the duct to the lower open end of the duct; and allowing the fish to swim up in the duct against the water stream therein. The incoming water is directed to flow into the duct, and the fish is separated from the flowing by means of a grating (16) inclining upwards from the top end of the duct to a separation plate (17) arranged above the water level in the duct. A device for taking up fish, using the mentioned method is also described.

A method for taking fish up from a body of water comprising the steps of providing a duct (14) having a lower open end below the water surface and an upper open end arranged at a floating working platform (5) above sea level; introducing water into the duct (14) from the upper open end to give a water stream from the upper open end of the duct to the lower open end of the duct; and allowing the fish to swim up in the duct against the water stream therein. The incoming water is directed to flow into the duct, and the fish is separated from the flowing by means of a grating (16) inclining upwards from the top end of the duct to a separation plate (17) arranged above the water level in the duct. A device for taking up fish, using the mentioned method is also described.

A system of harvesting sea creatures from a trench holding the sea creatures in seawater, including a trench, an injection well, and a harvesting apparatus that extracts the sea creatures from the trench. The trench includes a gate at one end of the trench. The gate insertable into an opening at the end of the trench to prevent seawater from entering or exiting the trench and removable from the opening to allow the seawater to enter or exit the trench. The injection well is positioned external to the trench and can receive the seawater discharged from the trench. The harvesting apparatus includes a conveyor that inclines. The conveyor includes a conveyor belt and a wedge at one end of the conveyor that contacts the bottom floor of the trench when the conveyor is inclined.

An assembly designed to encourage fish to enter a Coanda effect fish pumping system to allow delousing through the pump. The process quickly decelerates the fish in a water tank to their original speed of between 1.5 to 3 feet/second depending on pumping lift for a 10 inch diameter SILKSTREAM pump. As the fish guiding tube enters the tank, it is surrounded by a smooth diverging cone slowing the water speed to the original fish speed. The fish are then guided by the tubular assembly away from the water and lice into a second SILKSTREAM intake. The current changes within the SILKSTREAM Coanda effect pump provide delousing of the fish by orientating the fish in a forward direction as the fish pass through the pump.

An assembly designed to encourage fish to enter a Coanda effect fish pumping system to allow delousing through the pump. The process quickly decelerates the fish in a water tank to their original speed of between 1.5 to 3 feet/second depending on pumping lift for a 10 inch diameter SILKSTREAM pump. As the fish guiding tube enters the tank, it is surrounded by a smooth diverging cone slowing the water speed to the original fish speed. The fish are then guided by the tubular assembly away from the water and lice into a second SILKSTREAM intake. The current changes within the SILKSTREAM Coanda effect pump provide delousing of the fish by orientating the fish in a forward direction as the fish pass through the pump.

Techniques are disclosed for systems and methods to provide casting guidance for users of mobile structures, including watercraft. A casting guidance system includes a sonar transducer assembly and a logic device configured to communicate with the sonar transducer assembly. The sonar transducer assembly is adapted to be mounted to a mobile structure and placed in a body of water. The logic device is configured to identify one or more underwater targets in sonar data received from the sonar transducer assembly, determine casting guidance parameters corresponding to the one or more identified underwater targets, and generate at least one casting guidance identifier based, at least in part, on the determined casting guidance parameters. Subsequent user input, the sonar data, and/or the casting guidance parameters may be used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.