534 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



FiouRE 27. — Distribution of POFI catches of the blue marlin, Makaira ampla. Fractions indicate stations at which 

 catches were reported out of the total fished; decimals indicate average catch per 100 hooks per day. 



is the most abundant spearfish by weight, and the 

 annual landings ranged from a low of 512,000 

 pounds to a high of 679,000 pounds during the 

 period 1948 to 1952 (Otsu 1954). 



Food 



All reports indicate that this species is broadly 

 carnivorous on fish and cephalopods of the open 

 ocean. Nakamura (1942) tabulated the food 

 contents of 163 stomachs from fish taken in the 

 east Philippine Sea. Of these, 53 stomachs con- 

 tained squid, 11 Leiognathus, 12 BaliMes, 11 Auxis, 

 and lesser amounts of some 9 other genera of fish. 

 One contained a species of shrimp. In the POFI 

 catches, 36 stomachs contained food, of which 

 34 contained fish and 16 cephalopods. The com- 

 monest fishes in the stomachs were the tunalike 

 fishes, particularly Katsuwonus in the larger 

 individuals. Most of the cephalopods were squid. 

 In two additional stomachs from POFI catches 



the complete contents were not noted but speci- 

 ems of Xiphias gladius were preserved for later 

 examination (see p. 519). 



Seasonal occurrence 



Yabuta (1954) presented data which show that 

 the catch rate varies little thoughout the year in 

 the tropical seas in the vicinity of the Caroline and 

 Marshall Islands. Murphy and Otsu (1954) noted 

 that the catches of ampla by the nine Japanese 

 mother-ship expeditions in this same area showed a 

 minor peak in February and another in October 

 1951, but that the catch rate during the summer 

 months of 1951 was only about half that during 

 the summer months of 1950. 



North of the Carolines, however, there is evi- 

 dence of a seasonal migration and the peak abun- 

 dance which occurs in May at 12° to 16° N. lati- 

 tude, moves farther north with the season until the 

 peak is at 24° to 28° N. in September. Farther east 



