The book envisages the use of under-water electric field for catching fish. The use of electricity for catching fish has been practiced from a long time by the fishermen of different regions, the recorded evidence of which goes to 1886, when one Mr. Isham Bagg was issued a patent in Britain for catching fish with electricity. The author is the first person, who undertook fishing with electric seine as early as 1962 in Odisha, and in 2015 by developing an electric fish catcher. Originally, after several studies on fish electrophysiology, in different countries, the technique was applied in freshwater fisheries, like, streams, rivers, lakes and reservoirs, mainly for research and investigations and fisheries management. In this book, the author has tried to compile the basic principles of electrofishing system, with reference to design, construction and field application with the precautions and safety measures to be followed while construction and use of the electrofishing gear not only for the operational crews, but also for the fishes to avoid unnecessary mortality and injuries. The experiments and trial of electrofishing in sea water, particularly, of pulse trawling for flat fish, Hovercran shrimp trawling, and experiments with pelagic fishes in design criteria for electrical fish harvesting systems, which includes netless fish harvesting and mid-water electric trawling have find place in the book. The principal system components of electric fishing machine, its design consideration, power transmission, both from battery operated backpack and boat mounted electrode array and the factors affecting the efficiency of electrical fishing gear have been taken into account in the book.