eyes and the belly „ This is because if these external evidences are 

 conspicuous, the subcutaneous injury will accordingly be great and many 

 of the fish are bound to die later on„ Captured bait should not be 

 immediately placed in the bait tanks, but if circumstances permit, a 

 live~pound should be prepared in advance and the fish should be kept in 

 it temporarily to permit them to get over their excitement, to weed out 

 those which are badly hurt and about to die, and to permit the fouling 

 material that the fish vomit because of spiritual perturbation to be 

 naturally washed away» For transferring the fish to the bait tanks, it 

 is ideal if a strong, watertight port can be constructed in the vessel's 

 side, in accordance with Section 15, Article 9 of the inspection regula- 

 tions for wooden vessels, through which the bait fish can be poured into 

 the tanks, but where this sort of installation cannot be made they should 

 be transferred using several buckets (more successful than dip=nets) 

 and moving a few fish at a time without haste <> When the fish are placed 

 in the tank it must be lighted and the fish must be prevented from 

 bunching together in one place „ (If the fish do crowd together in one 

 place they may easily be injured and at the same time they may cause a 

 localized deficiency of free oxygen„) Care must be taken that the free 

 oxygen content does not fall below 5 cc per liter „ For about an hour 

 after the fish ssb put in the tank every effort should be made to give a 

 thorough circulation of water and at the same time the spray pump should 

 be used freely to supplement the supply of oxygen,, When more than an 

 hour has passed after the fish have entered the bait tank, with the new 

 pump circulation system the fear of an oxygen deficiency is completely 

 swept away a If, however, for some such reason as a defect in the opera« 

 tion of the pump a great many air bubbles should be produced in the sea= 

 water in the tank, there will be deaths from this cause so caution is 

 required,, Since fishes in general have the habit of swimming against 

 the current, provision should be made so that the water will gently circu= 

 late in a direction opposite to that in which the bait fish swim (clockwise 

 in most cases) „ When bait fish are transported to the South Seas fishing 

 grounds, deaths due to sudden rises in water temperature must be avoided 

 by immediately cooling the water in the bait tanks somewhat (2° - 3° is 

 enough) if the vessel encounters warm water zones with temperatures above 

 27°C in the case of S„ melanosticta (the lethal temperature is over 29°C, 

 but a margin of 2°C xs left because the saturation point of oxygen is 

 lowered as the water temperature rises) or above 29°C in the case of Eo 

 japonieus (lethal temperature over 31 C) o 



In addition, constant attention should be paid to the causes of death 

 treated in this study, and care should be taken to apply timely and 

 appropriate measures „ 



Summary 



1 This study is chiefly the results of a biological investigation of the 

 causes of death in the various types of mortality that occur when bait fish 

 that have been recently captured, commonly called "new" bait, are placed 

 in bait tanks for transportation,. 



'0 



