(b) Celebes Sea area (west of 125°E) 



Tunas Spear fishes 

 Depth Number % Number % 



A5 65 6.25 26 2„50 



76 182 8.76 36 1,72 



106 205 9.86 20 0,95 



It is regrettable that the data are not presented by specie So The 

 results from 1931 and 1932 show that there is a tendency for the good 

 fishing depths to form two levels. These were 4.5m and 129m in 1931, and 

 90m and l60m in 1932. 



In 1934- this tendency was not clear, but this is thought to have 

 been due to a simplification of the gear. The 193-!+ results indicate a 

 difference in the depths at which fishing was good as between the eastern 

 sea area and the Celebes Sea area. 



In any case, it is certain that the spearfishes occur in the shallower 

 levels and the tunas in the deeper ones, and this fact holds true for all 

 of the sea areas farther south. 



Considered from the facts detailed above, the maximum depth at which 

 these fishes occur is not yet known, however, it is thought that in the 

 southern seas, at least, they occur at much greater depths than has been 

 hitherto believed, and a certain number of fish are caught as far down as 

 I60m. The depth at which the fish occur in the greatest abundnnce differs 

 somewhat from area to area, but it is thought to be in general around the 

 100m level. Therefore it is believed that for fishing in the southern 

 seas gear so constructed that the hooks are at the 100m level would be 

 the most efficient. 



IV. Food 



These fishes are completely carnivorous and do not eat any vegetable 

 food. It is doubtful whether or not they have any selectivity with regard 

 to their food, and it is v/ondered whether they do not simply try eating 

 anything that moves or shines in the water. An examination of their 

 stomach contents reveals that they are truly miscellaneous, containing 

 various juvenile fisl:es, crustaceans, squid, nautilus, and other mollusks, 

 while even such things as jellyfish are frequently found. 



There are, of course, differences depending on the size of the fish, 

 the place, and the season, however, in general in the southern waters 

 squid are the most commonly seen natural food, followed by small fishes 

 which live around floating logs. Depending on the place, it is not at 

 all unusual to find them feeding solely on crustaceans. These facts should 

 not be interpreted as meaning that the tunas and spearfishes are parti- 

 cularly fond of these animals, but probably that they eat whatever is 

 most plentiful and easiest to catch. 



36 



