PRINCE ET AL.: LONGEVITY AND AGE OF ATLANTIC SAILFISH 



The weight of one air-dried otolith was measured 

 to 0.001 mg (±5%) using a Perkin Elmer AD2Z 

 ultra-microbalance. The sagitta was attached to an 

 aluminum stub, coated with gold, and examined by 

 SEM at 15.0-1500 x to observe the surface mor- 

 phology. External ridges on the rostral lobe of 

 sailfish sagittae, first described by Radtke and Dean 

 (1981), was one of the features used in this study 

 for age estimation. 



Following the methods of Haake et al. (1982) and 

 Wilson and Dean (1983), the other member of the 

 pair of sagittae was embedded in epoxy resin, and 

 a section was made in the transverse plane by polish- 

 ing both sides to 0.5 mm thickness with 600 grit 

 sandpaper and 0.3 ^m alumina polish. The internal 

 structure of the sectioned sagitta was examined with 

 an Olympus BH 2 compound microscope at 4.0 to 

 1200 x to aid overall orientation and understanding 

 of the growth of the structure and to interpret the 

 external ridges used for age estimation. 



imum longevity of this species by a considerable 

 margin. Although Jolley (1977) speculated that sail- 

 fish may live as long as 9 or 10 yr because the one 

 age 8 individual was not the largest specimen in his 

 sample, his estimated ages did not exceed 8 yr. In 

 addition, the maximum estimated age reported in 

 other recent studies was >7 yr (Radtke and Dean 

 1981; Hedgepeth and Jolley 1983). An Atlantic sail- 

 fish of estimated age 7 or 8 from the above sources 

 corresponds to an average size of about 25 kg (55 

 lb). Since our records indicate the age of the tag- 

 recaptured 24.6 kg (54 lb) sailfish was 13-15+ yr, 

 it appears that maximum longevity of Atlantic sail- 

 fish could be considerably older, perhaps over 20 yr, 

 because numerous specimens exceeding 45.5 kg (100 

 lb) have been caught during the last decade (Beards- 

 ley 1980). This reasoning assumes that sailfish have 

 indeterminate growth throughout their entire life- 

 time and that their size is proportional to age. It also 

 appears from tagging data that Atlantic sailfish may 



RESULTS AND DISCUSSION 



Our tagging records indicate that the tagged 

 Atlantic sailfish recaptured on 14 January 1984, was 

 at-large for 10 yr and 10 mo or 4,025 d. An experi- 

 enced charter boat captain estimated its size when 

 tagged to be 18.2 kg (40 lb). Bias in overestimating 

 the size of billfish during tagging has been a com- 

 mon problem since the inception of the Cooperative 

 Gamefish Tagging Program in 1954 (Prince 1984). 

 However, we feel that such an error would probably 

 not exceed ± 4.6 kg (10 lb) in a fish of this size, par- 

 ticularly when the experience of the captain making 

 the estimate is considered. The estimated age of a 

 sailfish of about 18.2 kg (40 lb) would be 2-4 yr based 

 on dorsal spine analysis (Jolley 1974, 1977; Hedge- 

 peth and Jolley 1983) and 3-5 yr based on otolith 

 analysis (Radtke and Dean 1981). Therefore, the ap- 

 proximate range in age of this sailfish based on tag- 

 ging information is 13-15+ yr. We feel these are 

 conservative figures based on the available informa- 

 tion and it is highly unlikely that this fish could be 

 younger than 13 yr. 



Maximum longevity of Atlantic sailfish was first 

 inferred by de Sylva (1957) to be at least 3 or 4 yr 

 based on length-frequency analysis (Fig. 1). A modal 

 group beyond 4 yr was indicated in his analysis but 

 year class designation was not discussed. Since 

 1957, estimated longevity of Atlantic sailfish has 

 been revised upwards (Fig. 1) to ^7 yr. Our tagging 

 records indicate, however, that the oldest Atlantic 

 sailfish aged by dorsal spine analysis (Jolley 1977; 

 estimated age 8) probably underestimates the max- 



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957 974 1977 1981 1983 984 



(1) (2) (3) (4) (5) (6) 



YEAR (STUDY) 



Figure 1.— Estimates of maximum longevity (yr) for Atlantic 

 sailfish from six different studies, 1957-84. 



495 



