FUNDAMENTAL STUDIES ON THE FISH LAMP 



By N. Y. Kawamoto 



Faculty of Fisheries, Prefectural University of Mie, Tsu 

 Mie Prefecture, Japan 



It is a well-known fact that animals react to light, positively or 

 negatively. Phototaxis of protozoa such as Paramecium and Euglena 

 has been studied by many investigators, and reaction of the earthworm 

 to light is also a well-known fact. Especially for insects, most efficient 

 lamps were recently discovered by means of studying complex factors 

 between visibility of retina of their eyes and their behavior. 



Fish lamps have been used in every country in the world since 

 ancient times to increase efficiency of fishing. In Japan, the torch-light 

 has been used since olden times for collecting the fishes. Nowadays, 

 electric fish lamps are employed by almost all fishermen in our country. 

 However, maximum efficiencies could not be expected because of un- 

 reliable theories about fish lamps. Dr. M. Tauchi (1926) and Dr. T. 

 Sasaki (1950) studied the effects of fish lamps upon fish shoals in the 

 sea, but the studies of the two investigators were chiefly on the side of 

 physics, and biological aspects were not fully considered. Therefore, 

 the fundamental reason for the method of using fish lamps was not 

 yet clear. 



Since 1947 the writer has studied, with co-investigators, the re- 

 lation between fish behaviour and fish lamps, using methods of physiol- 

 ogy and experimental zoology. 



For these experiments, many kinds of young marine fishes were 

 used and their reaction against various kinds of light in the dark 

 room was determined. Studies were made of the behaviour of adult 

 horse-mackerel in a rectangular net which was set down off the coast 

 of the sea in front of the Ichthyological Research Institute, Shimoda, 

 Izu peninsula, Japan. 



Experiments 

 In the laboratory, the writer adopted a lusterless, black, round 

 wooden tank, which was 100 cm. in diameter and 25 cm. in depth; and 

 the tank was divided radially into eight compartments, which were 

 open to each other at the center. The tank was filled with water to 

 a depth of 20 cm. and a color filter, was placed over a light window of 

 each compartment and 60-Watt Mazda electric bulbs were set 20 cm. 



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