United States Department of the Interior 

 Oscar Lo Chapman, Secretary- 

 Fish and Wildlife Service 

 Albert Mo Day, Director 



Special Scientific Report - Fisheries 

 No. 62 



(54) A STUDY OF THE CAUSES OF DEATH OF BAIT FISHES 



By Yasuo Suehiro l/ 



Translated from the Japanese language by 



W, G„ Van Campen 

 Pacific Oceanic Fishery Investigations 



CONTENTS 



Page 



Introduction. 1 



Death from lack of free oxygen., ................ . . . . . . . 2 



a) Abnormal respiration of sardines ....................... 2 



b) Lethal level of free oxygen. ........................... 3 



c) Comparative study of the capabilities of the old 

 and new *ypes of bait tanks as regards free oxygen 



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Death from sudden changes in temperature ....................... 19 



a) Chemical evidences of the fact that sardines do not 



have the ability to regulate their body temperature.... 20 



b) Resistance to high and low temperatures,. ... . .. ....... . 21 



1) Resistance to high temperatures. .. . .............. . 21 



2) Resistance to low temperatures.... 

 Death from wounds. 



a) Major wounds. 



b) Wounds to the outer surface of the body 



1) Loss of scales 



2) Lacerations 



3) Bites. 



c) Subcutaneous wounds... 



1) On the peak of mortality which appears several days 

 after the sardines have been placed in captivity. . 36 



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l/ Associated with the Imperial Fisheries Experimental Station; from 

 Journal of the Imperial Fisheries Experimental Station, No. 7 

 (Papers No. 52-60), pp* 51-90. 



