Sturm and Salter: Scomberomorus cavalla in Trinidad waters 



365 



except December (when only nine fish were sampled), 

 and ripe females were absent in April. Maximum per- 

 centages of females occurred from September to Octo- 

 ber and January to March. GSIs for females peaked 

 in September, November, January, and February. 

 Males showed similar patterns, though data were more 

 limited. The above observations indicated that S. 

 cavalla spawns throughout the year with more intense 

 spawning from September through March. 



Sex ratio 



Females were dominant in all size groups, both in gill- 

 net and hook-and-line samples, and in the peak spawn- 

 ing and non-peak spawning seasons (Table 4). The 

 degree of dominance varied with size class, type of 

 gear, and season. Dominance increased with size class, 



and all but a single specimen over 90 cm FL was 

 female. Females predominated to a greater extent in 

 the hook-and-line samples compared with gillnet sam- 

 ples. In gillnet samples, the proportion of females 

 decreased from 74% during the non-peak spawning 

 season to 62% during the peak spawning season, which 

 corresponded with an overall decrease in females from 

 77% to 63% in the respective seasons. In the south- 

 eastern United States, the sex ratio was also found to 

 favor females (Fischer 1980, Trent et al. 1983). 



Discussion 



Evidence for time of annulus formation in Trinidad 

 Scomberomorus cavalla is weak. Tracing of otolith 

 edges throughout the year suffered from a paucity of 



