Finfish and crustaceans respond to electric current by orienting themselves to face the anode and swimming toward that pole in a forced manner. By this means, the organisms may be led into nets, traps or pumps and the method is termed electrical fishing. In crustacean culture, electrical fishing has been employed in tanks and ponds, which are covered at the bottom by a layer of sand and/or gravel, in order to harvest the stock, which tend to bury themselves in the bottom layer.