602 



Fishery Bulletin 98(3) 



Figure 1 



Unstained transverse 0.5-mm section through the sagittal otoHth of P. filamentosiis from Seychelles, 

 viewed with transmitted light. Magnification: 16>< . Black dots along sulcus acousticus mark are suspected 

 annual increments 



Figure 2 



Unstained transverse 0..5-mm section through the sagittal otolith of A. virescens from Seychelles, viewed 

 with transmitted light. Magnification: 32x. Black dots along sulcus acousticus mark are suspected annual 

 increments. 



incremental pattern. Measurements on stained L. inah- 

 sena otoliths were performed out to the tip of the dorsal 

 lobe, at approximately 90° to the sulcus (Fig. 3). In all 

 species, when the increment structure became too closely 

 spaced to measure individual increments accurately, the 

 thickness of further increments was estimated by inter- 

 polation based on the remaining distance from the last 

 measured increment to the outside edge of the otolith, the 

 number of years expected in this zone, and the pattern 

 found in the previous increment widths. 



Following the recommendations of Francis (1990) and 

 Ricker (1992), we calculated the geometric mean regres- 



sion (GMR) of fork length at capture from otolith radius 

 at capture for each species. Back-calculated lengths-at-age 

 for each individual were then derived with the following 

 formula (Ricker, 1992): 



FL 



{ FL-b 

 O 



xQ 



+ h. 



where F/, = the estimated fork length at age ;'; 

 F/,, = the fork length at capture; 

 O^ = the otolith radius at capture; 



