September ono It is further thought that the density of its 

 distribution is greater in the Equatorial Current and the 

 Kuroshio and less in the Equatorial Countercurrento 



(6) The sailfish occurs in its greatest density in 

 several months before and after Juneo It comes far into the 

 coastal waters o 



The broadbill swordfish occurs in higher latitudes than 

 the marlins, and at some seasons is fairly numerous in the 

 Northeast and off Hokkaido and the southern Kurileso It is 

 also widely distributed in tropical waters, but in these areas 

 its commercial significance is not as great as that of the 

 marlinso 



The question of depth of occurrence, that is ^ vertical 

 distribution^, will be discussed along with that of the tunas 

 in the chapter on fisherieso 



When we examine the marlin which are taken in the area 

 in which the Kuroshio originates and in the South China Sea 

 area, we find that there is generally a marked difference in 

 their sex ratio at different seasonso For example, in the case 

 of the black marlin, there is from October to about April an 

 overwhelming majority of females and males are fewo Beginning 

 in April the males gradually increase in numbers and in July 

 and August the opposite situation obtains with an overwhelming 

 majority of maleso With the striped marlin this phenomenon 

 appears somewhat earlier than with the black marlin^ and in the 

 case of the wdiite marlin it appears about 3 months latero It 

 seems that the sex ratio of the sailfish is about even and does 

 not change greatly throughout the year, but adequate data have 

 not yet been collected for this species and for the short-nosed 

 spearfish and the little marlino It will be necessary to 

 inquire whether this phenomenon results from differences in 

 the season of migration of the sexes or whether it is caused 

 by differences in feeding habits which bring about a differential 

 representation in the catcho 



The fishery based at Takao operates with longlines, but 

 the fisheries of Suo and Keelung are mainly harpoon fisheries 

 and do not use baito The changes in sex ratios in the catch 

 of both of these fisheries show a tendency toward almost com- 

 plete agreement, Furthermorej during the height of their 

 spawning seasons in the waters adjacent to Formosa the sex 

 ratios of the sailfish, short-nosed spearfish, striped marlin, 

 and black marlin show values approximating 1 to lo The sex 

 ratios also generally average about 1 to 1 in the course of a 

 yearo Considered in this way, it can hardly be thought that 

 there is any sexual difference in food habits. Accordingly it 

 is thought that in the waters adjacent to Formosa, at least. 



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