A pump-equipped drag net, towed by a boat over the pond bottom has been used to harvest P. japonicus in Japanese shrimp ponds. The apparatus consists of a sled portion, and an attached bag net on the back of the sled. A horizontal pipe with spray nozzles is attached to the forward, bottom part of the sled. A water pump in the boat jets water (0.3 m³/min) under pressure (4 kg/cm²) into the pond bottom to a depth of 6 to 8 cm, where the shrimp are thus encouraged to leave the bottom. The net is towed at 20 to 30 m/min. This forward motion, plus a tickler chain on the lower leading edge of the net effectively causing shrimp to be captured in the conical net. This net is effective on P. iaponicus during the day, when the shrimp are normally inactive and burrowed in the pond bottom (Fast, 1992).