56 



34 

 32 



30 

 28 

 26 

 24 



22 

 20 



I 18 



10 



° FEMALES 



< MALES 



« SEX UNDETERMINED 



J L 



J L 



J I L 



40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 100 104 108 112 116 120 122 



LENGTH (CENTIMETERS) 



Figure 9. --Weight-length relation of dolphin. 



fish classed as "spent" (stage 5) comprised 2 

 fish of about 5 pounds and 5 fish of 10 to 11 

 pounds. 



Yellowfin 



In contrast to skipjack and little tunny, most 

 of the yellowfin were judged to be immature. Of 

 the 59 fish examined for sex, 14 had gonads so 

 immature that the sex could not be ascertained. 

 The remainder were mostly "immature" (stage 

 1) with a few "maturing" (stage 2). In view of 

 the size of these fish and their presumed age, it 

 would seem doubtful that yellowfin mature by 

 the end of their first year. 



Of the yellowfin which could be sexed, 

 males were in the minority (45 percent), al- 

 though the ratio did not deviate significantly 

 from 1:1. This is i n agreement with the sex 



ratio of the smaller (less than 80 to 90 pounds) 

 fish taken by longline near the Equator, but it 

 is in contrast to the sex ratio for the larger 

 longline-caught fish both near the Equator and 

 in Hawaiian waters, in which males strongly 

 predominate (Iverson 1956). The reason for the 

 change in sex ratio is obscure. 



Dolphin 



The dolphin showed a significant deviation 

 from the 1:1 ratio, with males (28.5 per- 

 cent) much less numerous than females (71.5 

 percent). All males were either "immature" 

 (stage 1) or in early stages of maturing 

 (stage 2). The females included stages 

 ranging from "immature" to "mature" (stage 

 4). The fish classed as "immature" ranged 

 from 1-1/2 to 8-1/2 pounds. Of the 12 fish 

 classed as "mature" (but not "running ripe") 



15 



