Trawl net layer-by-layer collecting device

A trawl net layer-by-layer collecting device comprising:

• a substantially rectangular frame configured to draw a plurality of trawl nets that are arranged in an up and down direction, the frame including an upper edge to which a net mouth edge of an upper net of an uppermost trawl net is anchored, and a lower edge to which a net mouth edge of a lower net of a lowermost trawl net is anchored;
• a pair of vertical bars disposed on opposed sides of the frame;
• at least one substantially horizontal slider having opposed ends slidably engaged with the vertical bars, the at least one substantially horizontal slider having anchored thereto at least one of a net mouth edge of a lower net of an upper trawl net and a net mouth edge of a lower net of the uppermost trawl net, and at least one of a net mouth edge of an upper net of a lower trawl net and an a net mouth edge of an upper net of the lowermost trawl net;
• a net-mouth opening and closing unit configured to lock the at least one substantially horizontal slider on upper ends of the vertical bars, and unlock the at least one substantially horizontal slider when locked so that the unlocked at least one substantially horizontal slider slides down along the vertical bars so as to switch opening and closing of net mouths of the trawl nets;
• and
• a controller configured to control an activation of the net-mouth opening and closing unit;
• wherein:
• the controller includes a timer, and a storage medium storing a predetermined net-towing time period as a timing for activating the net-mouth opening and closing unit;
• and
• the controller is configured to input a net-towing time obtained from the timer, and activate the net-mouth opening and closing unit upon arrival of the predetermined net-towing time period stored in the storage medium, so as to switch the opening and closing of the net mouths of the trawl nets.