The "tame iwashi" are us^ially supplied to the fishing boats after they 

 have been kept in the live-pounds for a week or longer and are thoroughly 

 accustomed to living in a confined space „ They are handled with carej and 

 the operation is carried out in the_form of a commercial transactions, for 

 example, when a bucket holding 8 sho / 3ol8 gallons_J' is dipped from the 

 live-pound, a bargain is made for so many yen per bucket, Latelyj because 

 of the general shortage of bait;, the skipjack fishermen have been making 

 every effort to assure themselves a supply, and there are some who make 

 contracts beforehand with the bait suppliers while others have hired persons 

 who do nothing else but buy bait for them„ At times they may even be forced 

 to load "wild bait" in the boats„ 



(4,) Bait in the fishing boat's bait wells 



Skipjack boats are equipped with live bait wells in which are kept the 

 iwashi from the live-pounds. The capacity of the live wells depends on the 

 rate at which the water in the boat can be exchanged and also on the species, 

 size, and condition of the bait and the degree to which they have become 

 accustomed to cramped quarters. 



(a) Deaths of bait fish due to insufficient oxygen in the water are 

 more frequent with larger fish than with small oneSo 



(b) Deaths resulting from injury in handling and from stimulation and 

 excitement by conditions in the bait wells are more frequent with small fish 

 than with large ones. 



(c) As between the ma iwashi / Sardinia melanosticta / and the katakuchi 

 iwashi / Engrauli s .jaTPonicus /„ the former is more resistant to injury and 

 excitement, while the latter is comparatively resistant to oxygen deficiency, 



(d) The water temperature has an effect on the viability of the fish. 

 If the temperat'ore rises, injured or weakened fish will die all the faster. 

 If the temperature falls, even fish which are in a dying condition will 

 have their lives prolonged somewhat, Consequentlys the number of deaths 

 in the bait wells increases and decreases as the water temperature rises 

 and falls, 



(e) Resistance to death from lack of oxygen is gi'eater in the anchcry 

 than in the sardine, and greater in small sardines than in large ones. When 

 the fish in the live=well mill around excitedly^ it is because the oxygen 

 co!icentration is insufficient, being below 1 cc per liter, and the water 

 rust be changed. It is said that the maximum concentration of fish in a 

 iive-well which is advisable is about 8 gallons of sardines per cubic 

 meter, 



(f) There appears to be a tendency for more bait to die of injury, 

 excitement, and so forth when the fish are noticeably lean than when they 

 are fat. 



In selecting ba:^t fish the first consideration is to choose those which 

 the skipjack like to eat, and the second thing to consider is the ease with 



39 



