On May 5, 19, a crab trap (2) is made with a spring-type frame consisting of wires with a diameter of approximately 4.4mm, laid in a horizontal cylindrical shape, and covered with 26mm PE netting. The funnel-shaped entrance is located on both sides of the trap. Bait is placed inside the trap to lure and catch the target organisms. Fishing is done along the river or stream from 4 to 5 PM, and the traps are retrieved from 5 to 6 AM the next day. A total of three sets of traps, each consisting of 100 to 200 traps, are moved along the river each day. The time required to set each set of traps is about 30 minutes, and the time required to retrieve them is about 1 to 1.5 hours. - Season: Early September ~