Yellowfin 



Measurements were made on 147 yellowfin, 

 which averaged 6. 5 pounds (54 cm. ) and ranged 

 from 1 to 18 pounds (29 to 72 cm.) (table 6). 



The monthly data shown in figure 7 indicate 

 the progression of a mode starting at about 5 or 

 6 pounds in June and advancing to about 10 pounds 

 in November. This apparent growth agrees well 

 with that observed for a yellowfin held in captiv- 

 ity, which increased in weight from about 5 

 pounds when it started feeding on July 2, 1951, 

 to 1 1 pounds when it died on January 13, 1952 

 (Tester 1952). 



Based on a study of the ovaries, June (1953) 

 concludes that yellowfin in Hawaiian waters 

 spawn from the middle of May to the end of 

 October. Moore (1951), from a study of the 

 weight composition of the commercial pole-and- 

 line and longline catches, concludes that yellow- 

 fin attain an average weight of about 7 pounds 

 (54 cm. ) by the end of their first year and an 

 average weight of 46 pounds (103 cm.) by the 

 end of their second year of life. Our data agree 

 well with Moore's estimate of the weight at the 

 end of the first year, i.e., the mean weight of 

 our troll-caught fish is 6.8 pounds during 

 August, assuming this month to be the middle 



of the spawning period. However, fish which 

 average 7 pounds in August and 10 pounds in 

 November would have to grow very rapidly dur- 

 ing the winter, spring, and early summer to 

 attain a mean weight of 46 pounds during the 

 following August. It may be that our estimate 

 of 10 pounds in November is biased by selective 

 sampling, i.e., the fish may tend to move out 

 of the area as they get larger, although the ad- 

 vancing mode noted above seems to indicate the 

 contrary. 



Dolphin 



Measurements were made on 198 dolphin 

 which averaged 6. 8 pounds (72 cm. ) and ranged 

 from 1-1/2 to 37 pounds (41 to 12 1 cm.) (table 7). 



From the monthly weight distribution, shown 

 in figure 8, there is some indication of bimodality 



I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 

 WEIGHT (POUNDS) 



2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 

 WEIGHT (POUNDS) 



Figure 7. --Weight composition of yellowfin by 

 months for the combined data of 1951 to 1955. 



Figure 8. --Weight composition of dolphin by 

 months for the combined data of 1951 to 1955. 



11 



