/"English abstract omitted 7 



Introduction 



To promote efficiency in transporting the bait fish used in skipjack 

 fishing, the type of bait tank used hitherto, that is one in which the 

 water is circulated only by the motion of the boat* is unsuitable,, For 

 this reason in July, 1931, this Station, in cooperation with the Shizuoka 

 Prefecture Fisheries Experiment Station, planned some improvements, re- 

 built the bait tank of the Shizuoka Station's guide vessel, the Fuji 

 Maru, and installed new equipment to circulate the water thoroughly by 

 means of a pump. Since that time basic experiments have been carried on 

 along with practical tests and real results have been steadily obtained 

 until finally the point has been reached where the efficiency of holding 

 bait fish has advanced remarkably.. As is made clear in !Jc . 3 of the 

 Journal of the Imperial Fisheries Experimental Station,-) both the useful 

 volume and the density of contents of the new bait tank are about 40$ 

 greater than those of the old-style tank so the total amount held is 

 about twice as much, Furthermore the death rate has been reduced greatly 

 to less than 10$, Bait fish which have just been captured, hitherto 

 thought impossible to transport because of their high death rate, that is 

 to say, what are commonly called "new bait", have been transported in 

 tests, but as was expected the mortality was heavy and several trials all 

 ended in failure. This must, after all s be ascribed to a number of defects 

 in the methods of handling the bait fish due to the fact that insufficient 

 research had been done on the causes of bait mortality., In order to take 

 the most appropriate measures against mortality, it is necessary to make 

 a detailed study of all of the causes of death in the bait fish such as 

 deficiency of free oxygen, sudden changes in the water temperature, wounds, 

 and so forth., 



With such views in mind, the author, during the approximately four 

 years from 1932 to 1935, carried on the investigations indicated in the 

 title of this paper, using as material sardines, Sardinia melanosticta , 

 and anchovies, Engraulis japonicus , of a size suitable for skipjack bait, 

 at Enoura and Mito in Shizuoka Prefecture, aboard the Fuji Maru at anchor 

 in Mito Wan, at the Kanagawa Prefecture Misaki Marine Laboratory, and at 

 Katsuura and Tateyama-Hojo in Chiba Prefecture , 



This study was undertaken on the orders of the Chief of the Station 

 and of Technician Itaro Takayama,, The study owes not a little to the 

 assistance of the personnel of this Station, the personnel of the Shizuoka 

 Prefecture Fisheries Experiment Station, to the Masudas, father and son, 

 of Shishihama in Shizuoka, Tadanori Also and haruo Xamamotu of Mitsu in 

 the same prefecturejJDr^ Ikusaku Amemxya, professor in the Faculty of 

 Agriculture of the Tokyo Imperial University, and Dr„ Sadanori Mita, 

 professor in the Faculty of Medicine, have constantly given extremely kind 

 guidance^ In the preparation of the report Technicians Saburo Hoshino, 

 Toru Sato, and Kinosuke Kimura supplied profitable advice., I wish here 

 to express my heartfelt thanks to all of these persons „ 



