a few fish fall onto the deckj, and even those which do not are exposed 

 to the air during the time that they are being carried in the scoop-net „ 

 Being fish that are weak even in the water,, it need hardly be said that 

 the life of the bait is very precarious when it is exposed to the air 

 Therefore,, in order to test how long bait fish can live when left out of 

 the water, the author carried out an experiment on the subject indicated 

 by the heading of this section on March 25 , 1934 , (clear, atmospheric 

 temperature 15°C) aboard the Fuji Maru using 50 fish that had been 

 caught several days earlier,, The fish were taken from the bait tank one 

 by one, their bodies were confined so that they had no freedom of move- 

 ment, and they were left in the air, the time that elapsed until they 

 were completely dead of suffocation being determined in each case 8 The 

 lethal time was recorded as the period from the time the fish were taken 

 out of the water and left in the air until the complete cessation of 

 respiration, accompanied by two or three convulsions passing from the 

 anterior to the posterior part of the body„ In this way it was possible 

 to make the graph shown in Figure 15, with the lethal time on the vertical 

 axis and the body weight of the fish on the horizontal. 



The first things that one perceives in looking at this graph is that 

 as the body weight of the fish increases the lethal time is extended to 

 a greater or lesser degree, and that for a difference in body-weight of 

 about- 50 grams there is a difference of almost 50 minutes in the lethal 

 time Also, the hypothetical curve has a sigmoid shape with reference 

 to the horizontal axis from which it can be inferred that under conditions 

 similar to those of this experiment, no matter how small the fish may be 

 it will noi die in less than about 10 minutes, and no matter how large 

 a fish may be, it will not be able to maintain life longer than about 

 40 minutes o (If the fish is not restrained and is allowed to jump about, 

 it will die in a shorter period of time») However, it is self-evident 

 that fish should not be left for such long periods of time in the air if 

 it is intended to return them safely to the water, since the experiments 

 described above record the period of time until the fish were completely 

 deads 



Measures to be Taken to Prevent Deaths 



These involve eliminating insofar as possible the external factors 

 described above as being the causes of death of bait fishes, so I will 

 attempt to avoid repetition here and will only sixnmariae the items which 

 should be given the most careful attention when transferring newly-caught 

 fish to the bait tanks of a vessels 



First of all, in catching bait fish the fishing should not, of course, 

 be carried on when the weather is stormy Minute care should be given 

 to the method of operating the fishing gear so as to avoid, as far as 

 possible, causing brain contusions, ruptures of internal organs, and 

 other similar dangerous subcutaneous injuries that give rise to the 

 breakdown of the tissues In purchasing bait fish from bait fishermen, 

 attention must be paid to the loss of scales and bleeding around the 



