294 



Fishery Bulletin 98(2) 



1200 



900 -■ 



g> 600 -- 



300 





om^'^ 



theoretical 



X observed 



a backcalculated 



10 



1 



20 



Age (yr) 



30 



40 



Figure 4 



Observed, backcalculated, and theoretical lengths at age for yel- 

 lowedge grouper, E. flavoUmbatus. 



Wt = 5.0 X 10-'^TL2 80 



(n=335, r2=0.88). 



The exponent b was significantly different from 3 

 (Mest, <=17.98, P<0.001 ). For the yellowmouth grou- 

 per this relationship was 



Wt = 1.88 X 10-5FL2 94 



. (n=50, r2=0.94) 



with b being significantly different from 3 (^-test, 

 <=5.19,P<0.001). 



Discussion 



The annual formation of opaque rings was dem- 

 onstrated in both yellowedge and yellowmouth 

 groupers in the study area. Deposition of annuli 

 occurs over a protracted period of about five 

 months, beginning in the wet season and con- 

 tinuing into the early part of the dry season. 

 A protracted period of annulus deposition has 

 been observed in other grouper populations, 

 e.g. Mycteroperca phenax (Matheson et al., 

 1986), Epmephelus itajara (Bullock etal., 1992), 

 and M. microlepis (Hood and Schlieder, 1992). 

 Factors affecting annulus formation in grou- 

 pers have been discussed by Moe (1969), who 

 attributed annulus formation in red grouper to 

 spawning and related physiological processes. 

 In contrast, in our study area, annulus forma- 

 tion in the yellowmouth and yellowedge grou- 

 pers occurred after the period of peak spawning from 

 about April to July for both species (Manickchand- 

 Heileman and Phillip^). Formation of annuli after 

 spawning was also reported for the Nassau grou- 

 per, E. striatus, in the Cayman Islands (Bush et 

 al., 1996). Annulus formation has also been found 

 to occur out of phase with spawning in other grou- 



