FISHERY BULLETIN: VOL. 79, NO. 1 



90 



80 



70 



o 



z 



q: 

 o 



60 



50 



40 



EASTERN PACIFIC ( OTOLITH ) _ 

 CENTRAL PACIFIC (OTOLITH) 



Loo 



1 42 .5 cm 



102.0 cm 



JOSEPH a CALKINS (LENGTH FREQUENCY) 107.5cm 



JOSEPH a CALKINS (TAGGING , CORRECTED ) 88.1 cm 



.JOSEPH a CALKINS ( TAGGING . UNCORRECTED ) 72.9 cm 



K 



0.29 

 0.55 

 0.41 

 0.43 

 0.82 



-O.I6yr 

 -0.02 yr 



12 



18 



24 

 MONTHS 



30 



36 



Figure 5. — The von Bertalanffy growth curve of skipjack tuna in the eastern Pacific as determined by otolith examina- 

 tion and its comparison with von Bertalanffy growth curves of previous studies from that area and the central Pacific (for 

 full reference, see text). 



Table 3. — Length-age regression parameters for the two linear 

 growth stanzas of central Pacific yellowfin tuna: N = number of 

 data and RSS = residual sum of squares. 



compared (Figure 8). As with skipjack tuna, the 

 von Bertalanffy model gives a poorer fit than the 

 linear segmental model. Although the probability 

 for the distribution of residuals to be randomly 

 distributed along the von Bertalanffy curve was 

 significant at P = 0.05 (run's test, table of critical 

 values: r = 7, ni= 7, n2 = 7), clustering of pluses 

 and minuses occurred. The run's test for the linear 

 segmental model also showed randomness (r = 9, 

 «i = 6,n2 = 8; table of critical values, P < 0.05), 



and was an improvement over the von Bertalanffy 

 curve with the increase in the number of runs from 

 7 to 9. 



The results of our study on yellowfin tuna within 

 the size range examined agree with most earlier 

 studies for this species from the eastern and cen- 

 tral Pacific Ocean. The results of aging by scales 

 (Yabuta et al. 1960) and modal progression in 

 length-frequency distributions (Hennemuth 1961) 

 are given for comparison (Figure 6). It has been 

 suggested that growth of yellowfin tuna in the 

 eastern Pacific between the lengths of 50 and 100 

 cm is linear and that growth rates are 0.6-1.0 

 mm/d (Inter- American Tropical Tuna Commis- 

 sion 1972, 1974). 



CONCLUSIONS 



Daily growth information provides much 

 greater insight into the growth patterns of teleost 



158 



