lures, it may be that in such cases the motion of the bait 

 exercises a kind of attraction. Of course the significance 

 of the shape and coloring of the artificial lures that are 

 used should not be forgottenc 



A remarkable difference from the feeding habits of the 

 tunas is that these fishes do not seek food on the bottomo 

 Considering the construction of their jaws, it is very natural 

 that they cannot feed on demersal organisms „ It is certain 

 that they do not feed on the bottom^i but it appears that the 

 broadbill goes rather deep^ and in northern waters they eat 

 cods Sebastodes p and myctophidSc The istiophorids in southern 

 waters also sometimes eat deepsea fishes^ Naturally the 

 vertical distribution differs markedly with sea conditions j, 

 but there is danger in judging from the food of the fisho For 

 example, even though they may feed on such deepsea fish as the 

 myctophids, it is more reasonable in view of the difference 

 between the depths at which these fishes occur during the night 

 and during the day to think that the marlins catch and eat them 

 during the night when they come up into the shallow levels than 

 that they dive deep to catch themo 



iiio Spawning and growth 



The life history of these fishes is almost completely 

 unknown. It is thought that,-, like the tunas, they spawn grad- 

 ually over a broad area of the seao 



Figure 16o— -ao Ripe egg of black marlin (X30), be Ovarian egg 

 of short=nosed spearfish (X30)s, Co Pipe egg of 

 sailfish (XSO),, d„ Ripe egg of tuna (X23)o 



Figure 17o— -Upper left - juveniles of Atlantic Ocean sailfishg 

 lo Total length 9 mm,, 2, Total length 14 mmo p 

 3o Total length 60 mmo Upper ^ight = larval 

 sailfishs 1, 2c Total length i 6 mmo Middle - 

 juvenile broadbill, lower g a Larval sailfish 

 (body length i 3 mm„)p b. Juvenile sailfish 

 (body length t 12 mmo \ Cc Juvenile sailfish 

 (body length L 140 mmo) 



The facts that are known concerning the spawning of the 

 short-nosed spearfish axe briefly as follows^ The spawning 

 habits of this species in other sea areas is as yet unknowi ^ 

 but in the waters adjacent to Formosa it spawns around November 

 to Decembero The area in which it spa^iras is centered 150 miles 

 offshore in the Pacific and the fish are almost never seen 

 within 30 miles of the coastc At the season mentioned, fish 

 with ripe eggs and those with unripe eggs are taken togetherg 

 showing that spawning extends over a long period of timeo Eggs 



41 



