LOG,„TRUNK LENGTH 



J J A S O N D J 

 19 70 



Months 



M A M J J 

 197 1 



Figure 9. — Sex ratio of 398 sailfish expressed as a percent 

 of each monthly sample. 



age has been observed by de Sylva (1957) and Wil- 

 liams (1970), but no specific coirelations have yet 

 been made with regard to sex. Perhaps a difference 

 in growth rate would account for the size disparity 

 between sexes. 



A significant difference was observed between the 

 length-weight relationships by sex (/.05=3.121, d.f. 

 410). Females smaller than 137 cm trunk length were 

 notably heavier than males of comparable length 

 ( Fig. 10). Merrett ( 1968: 165) found no sexual distinc- 

 tion in the length-weight relationship of 120 Indian 

 Ocean sailfish 126-194 cm "eye to fork length" (11.3 

 to 47.6 kg). Many of the fish he examined were 

 considerably larger than those I weighed and mea- 

 sured (see Table 3). However, Williams (1970) ac- 

 knowledged that a sexual difference in the length- 

 weight relationship may exist, as is the case in mar- 

 lins. 



Reproduction 



Gonadal tissues have not yet been fully evaluated 

 microscopically. However, in assessing reproduc- 

 tive development from slides of Indian Ocean bill- 

 fish gonadal tissue, Merrett ( 1970) reported that ovu- 

 lation was probably not an all-or-none process, and 

 that many resting oocytes were "reabsorbed." Simi- 

 larly, Moe (1969) found that not all developing oo- 

 cytes reached maturity in red grouper, Epinephelus 

 morio. Many "rejuvenilized" during a resting stage 

 subsequent to the spawning period. Beaumariage (in 



TRUNK LENGTH (cm) 



Figure 10. — Relationship of trunk length to weight for 412 

 Atlantic sailfish. 



press) noticed a similar condition in young king xms:.- 

 kere\, Scomberomoruscavalla. Such developmental 

 characteristics will be considered when sailfish 

 slides are examined. 



Fecundity was estimated for eight sailfish varying 

 in size from 17.2 to 27.4 kg (38.0 to 62.5 lb) (Table 4). 

 Counts of "ripe" oocytes yielded fecundity esti- 

 mates varying from 0.8 to 1.6 million ova. These 

 oocytes constituted fewer than half the total number 

 in the ovary. Voss (1953 ) estimated total fecundity of 

 sailfish to be 2.3 to 4.7 million ova, probably an 

 exceedingly high number of "ripe" oocytes. His 

 counts were made from an ovary only 4.2% of 

 specimen weight (Voss, 1953:227). Although he 

 gave no size range for oocytes counted, I suspect 

 they were not fully developed. I counted only the 

 largest ova, 12 to 1.4 mm in diameter, from ovaries 

 8.1 to 12.7% (.r= 9.9%) of specimen weight. 



Correlation of gonadal tissue evaluations, larval 

 sailfish abundance, and age estimates will allow def- 

 inition of spawning frequency and age at maturity. 



86 



