Figure 8.— The internal structure of the lapillus of a 20.5 kg 

 sailfish (400 X). Bar = 50 yum. 



Figure 9.— The lapillus of a 20.5 kg sailfish viewed under 

 transmitted light. Five layers are shown (40x). 



he examined could be aged by the spine analysis, 

 and it was particularly difficult for him to age 

 larger specimens, while we read 64 of 65, or 98% , 

 of the otoliths. Our percentage might be lower for a 

 larger sample or older fish, but an age estimate 

 was usually possible from one of the two sagitta 

 present in the fish. We did not find it difficult to 

 resolve the age of our largest specimens. 



55 



50 - 



45 - 



40 - 



35 



XS 30 



25 

 20 



15 

 10 



• PMfwt M«tto4 («« Sflva 1957) 

 X DoTMl Fin Spin* Anolflls [Mitj 1977) 

 « OMittit (PrntMl S«««y) 



Tt 



^ Ti 



1.1 



T: i 



S 



-L 



_L 



12 3 4 5 6 7 



AGE (YEARS) 



Figure lO. — Comparison of relationships between the mean 

 weight of sailfish and estimated age. Bars represent ranges. 



The age-weight relationship developed in our 

 study from otoliths, and by Jolley (1977) from 

 analysis of dorsal fin spines (Figure 10) indicates 

 that weight attained at ages 1 through 3 are about 

 SO'/f less than those estimated by de Sylva (1957) 

 and Koto and Kodama ( 1962). Tag data (Mather et 

 al. 1974) are inconclusive due to the small number 

 of returns. Our two largest specimens (estimated 

 age 7) weighed 26.4 and 27.7 kg and were 228.6 

 and 226.1 cm TL. This is similar to Jolley 's largest 

 fish of 26 kg at our equivalent age 6, but his larger 

 fish could not be aged with the fin spine method. 



Sailfish are multiple spawners (Jolley 1977), 

 which could account for the range of weights in the 

 different age-groups. A study of internal patterns 

 in otoliths might make it possible to determine 

 when an individual fish spawned. The internal 

 microstructure could be a permanent calendar of 

 the physiological history of the fish. Further study 

 on the micromorphology and internal structure of 

 the otolith should reveal valuable information. 

 The internal increments occurred at a frequency 

 of 13 or 14 increments in each major assemblage 

 which could be evidence of a lunar periodicity. 



365 



