held at Mito Wan in Shizuoka Prefecture., These fish were placed one at 

 a time in a partly filled basin of water and allowed to jump about for 30 

 seconds. Then the number of scales which had fallen off during that 

 time were accurately counted- As a result it was found that sardines 

 averaging 13,3 cm in length lost an average of 62 scales in 30 seconds. 

 Scales were lost most easily from the loiter sides of the fish and very 

 similar values were obtained •-";? gar dies? of the size of the specimen,, How- 

 ever, the rate of scale loss appears to be fastest at first and to gradually 

 diminish so that it is net possible to calculate the number of scales 

 lost for units of time from 1 second to 1 minute on the basis of these 

 results. 



Looking at the results shown in Table 22 it can be gathered that 

 sardines lose their scales very easily and that in a fairly short time 

 with the operation Gf a certain amount of external force almost all of 

 the scales would be lost. As a matter of fact s , quite a few individuals 

 are found among bait fish which have lost almost all of their scales. 

 This means that an extremely large proportion of the fish are liable to 

 receive other mortal injuries because of the rubbing off of their scales. 



2) Lacerations 



These are injuries to the surface of T,he body received from the 

 time the fish are taken in the net to after they are placed in the bait 

 tanks,, especially in the case of fish which have lost scales. The external 

 force applied is not great enough to cause the subcutaneous wounds 

 described in the next section^ and most of the injuries consist of the 

 rubbing off of the epidermis with more or less bleeding*, the wounds not 

 being directly related zo des' 



3) Bites 



Among bait kept in live-pounds there are occasionally discovered 

 individuals which have lost vitality through rather large wounds on the 

 tail and other parts of the body^ as is shown in Figure 9 C . Many wounds 

 of this character are bites resulting from the attacks of mackerel which 

 are mixed in with the bait fish in captivity. It should be ascertained 

 whether or not any mackerel are mixed in with the bait s , and if there are, 

 they should be speedily fished out,, E^en where such injuries are 

 fortunately not fatal, there is bound to be some danger of the fish 

 finally dying of bacterial infection wnen the water temperature is high. 



c) Subcutaneous wounds 



These are divided into subcutaneous hemorrhages, broken bones,, 

 brain contusions, and ruptured viscera,. In many cases subcutaneous 

 hemorrhage is associated with brain contusions or ruptured viscera, but 

 sometimes they appear alone,- In either case this type of injury consists 



34 



