144 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



350 



300 



o 



z 

 =) 

 o 



•± 150 



100 



50 



ni 



AGE GROUP 



■2L 



■m 



Figure 13. — Age-weight curves of tunas from waters off Japan and Mediterranean Sea compared to curve of Hawaiian 



vellowfin. 



demonstrates the most rapid growth but shows no 

 semblance of a point of inflection. As the curves 

 have been fitted to the data by eye, there may be 

 errors in the interpretation, but the curves show 

 the great variation in results of age and growth 

 studies of tunas. 



Westman and Neville (1942), in a study of 751 

 length frequencies of bluefin tuna (Thunnus thyn- 

 nus) taken in waters off New York by both the 

 troll and chum fisheries, show the catch to be 

 made up of three distinct age groups. Ages were 

 assigned by scale readings. A comparison of size 

 of fish by ages with the Hawaiian -yellowfin study 

 shows more similarity than the curves indicate in 

 figure 13. Even so, the growth rate of the Atlantic 

 bluefin as shown by plotted data (fig. 14) is not 

 so rapid as yellowfin growth during the early years 

 of life. 



150 r 



100 



50 



AGE GROUP 



18 24 



MONTHS 



30 



36 



42 



Figure 14.— Lengths of dominant size groups of bluefin 

 tuna taken off Long Island, New York, by Westman 

 and Neville (1942), plotted against the calculated growth 

 curve of Hawaiian yellowfin. 



