Spinal sections from 193 specimens were read 

 once. Initial results indicated that about 64 of the 

 sections were clearly legible. These readings ranged 

 from age groups through VII (Table 2). Age group 

 III was most numerous. 



Narrow translucent (dark) and wider opaque 

 (white) zones can be easily distinguished in a spinal 

 section from one specimen (Fig. 7). The radius of the 

 first circulus is greater than each successive radius. 

 The central portion of all spines is vascular, and in 

 large specimens this area often obscures the first and 

 second circuli. Consequently, determination of the 

 placement of these first circuli will depend upon 

 careful examination of their positions in younger 

 specimens. 



Several additional methods have been tried to 

 facilitate readings. A "burning technique" used by 

 Christensen (1964) to emphasize annular marks on 

 otoliths of the North Sea sole, Solea solea, was not 

 effective on sailfish spinal sections. Staining with 

 various concentrations of methylene blue was 

 likewise ineffective. A magnified image produced by 

 projection with a Bausch and Lomb overhead pro- 

 jector was not sufficiently clear to enumerate all 



Table 2. — Age readings of Atlantic sailfish using best sec- 

 tions from fourth dorsal fin spines. 



No. circuli 

 Frequency 



II 



15 



III 



21 



IV 



12 



V 



5 



VI VII 



2 2 



N = 64/193 



Figure 7.— Section from the fourth dorsal fin spine of a fe- 

 male in at least age group VI, wt= 19.958kg, Dec. #10 - 

 1970. 



circuli. Several spinal sections have been decalcified 

 and stained with varying degrees of success. Some 

 progress is now being made using these techniques. 



Results thus far available from this study express 

 the need for growth equations based upon accurate 

 methods of aging. Females were found to be consis- 

 tently larger than males (Table 3 and Fig. 8), and the 

 sex ratio changed appreciably during the season; 

 65% of the sailfish examined from December 

 through May were females (Fig. 9). 



Nakamura and Rivas (1972) also noted that female 

 sailfish from the Gulf of Mexico sport fishery were 

 typically larger and more numerous than males. 

 Considerable variation in sailfish weight at a given 



Table 3. — Weight and trunk length of Atlantic sailfish 

 examined May 1970 through September 1971. 





Mean 



Weight 



Trunk 



Number individuals 



weight 



range 



length 

 range 





(kg) 



(kg) 



(cm) 



Total = 412 



17.0 



0.5-39.5 





Males 182 



14.9 



2.3-27.4 



70.0-144.0 



Females 230 



18.7 



0.5-39.5 



42.5-151.5 



Total >18.1 kg = 177 









Males 50 



20.6 







Females 127 



23.6 







Male N-182 

 Female N 230 



10^ 



ion 

 it cd 



-o 



CD CN 



Weight (kg) 



Figure 8.— Percent frequency distribution of 412 male and 

 female sailfish by weight. 



85 



