Paragraph 1 Attracting Skipjack with Lights 



Experiments using fishing lights to catch skipjack have not been 

 thoroughly gone into as yet, but we have occasionally heard of cases where 

 skipjack were attracted to lights which were being used to catch other 

 kinds of fish. There is little data to go on and it would be hard to 

 reach a definite conclusion, but there is a great need for further inves- 

 tigation on this point. The facts which we have are all from cases where 

 fish other than skipjack were the object of the operations and the lights 

 were used in waters far from the skipjack grounds. The strength of the 

 lights, too, was not adjusted with the object of attracting sklpjacko 

 In view of this, it is thought that some degree of success could be 

 expected from such a raethod„ 



(1) A report of catching skipjack by the use of lights 



According to a report by MTo Umekichi Shiozaki, skipjack were 

 successfully attracted with lights near Uwashima in Ehime Prefecture on 

 August 10, 1934. o 



(a) Catching skipjack by means of a purse seine 



Place <, o o Near Okinoshima and Fatanarabishima in the waters off Uwashima 

 in Ehime Prefectiire. 



Time „ « o August 10, 1934. (first day of the seventh month of the moon 

 calendar) 



Gear „ „ <, Purse seine, 660 yards long, 132 yards deep 



Lights „ o Underwater lights, 24 •= 32 volts, 170 - 200 wattSo Five 

 lights, one per vesselo There were four light-boats and one fishing boat. 

 Their disposition was as shown in Fiffure 15, with the fishing boat at the 

 center of a square having one of the light-boats at each of the corners„ 

 The distance from the fishing boat to the light-boats was 4.00-500 meterSo 



Operation - Each boat lowered its light from 1 to 2 meters below the 

 surface and illuminated 6 - 7,000 tsij-bq /~TN„ 1 t subo - 3.31 sq„ meters_7 

 of the sea surface. The lights were kept on from 4 to 8 hours, and as 

 the fish assembled the fishing boat ordered the light-boats to close in. 

 The light-boats slowly brought their schools of fish in to the center 

 and when all of the fish were assembled in one group, the light-boats 

 turned off their lights. The fishing boat then shot its net and surrounded 

 the lisho 



Concentration of fish . . . Since the preceding evening, each light-boat 

 had been using a 32-volt 170-watt light (total 5 lights). In the beginning, 

 the young sardines gathered all around o After a few hours, countless 

 skipjack assembled. About 3s00 A.M. the boats drew in and the net was 

 shot. About 5s00 A.M. iirfien the lifting of the net was begun, there were 



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