618 



Fishery Bulletin 98(3) 



100 

 80 

 60 

 40 

 20 



1 160[ 



I 120: 



S ^ 80 

 13 40 



CD 



ro 



Ages 1.2, & 3 



JFMAMJ JASOND 



120 



80 



40 







Ages >6 



JMMJSNJMMJSN MMJS JMMJSN 

 160r 160r 



Ages 4, 5, & 6 . __ 



80 

 40 

 0. 



%^.f^^^ 



JFMAMJ JASOND 



Month 



JFMAMJ JASOND 



Figure 4 



Percentage, by month, of otoliths with an annulus on the edge and mean monthly 

 marginal increments with standard errors for all age classes pooled into three 

 groups for common snook, Centropomus undecimalis. from south Florida waters. 



(Fig. 8). Most (749^) transitional-sex-stage fish were cap- 

 tured during September-November, shortly after the end 

 of the spawning season, suggesting that sex reversal of 

 postspawning males takes place shortly after spawning. 

 The small number of transitional-sex-stage fish in our 

 sample suggests that sex reversal occurs quickly. 



During the 13-month experiment designed to document 

 sex reversal, three males changed into females. The 137 

 four-year-old fish whose sex we monitored were initially 



1200 r 



1000 E- 



800 



600 



400 



200 







1200 



1000 



800 



600 



400 



200 

 



l.|.i..!. 



east coast 

 n=1,880 



20 



Age (yr) 



Figure 6 



The von Bertalanffy growth curves for common snook, 

 Centropomus undecimalis. from the east and west 

 coasts of Florida. Parameter estimates are given in 

 Table 4. 



sexed in July 199.5 and ranged in length from 445 to 608 

 mm (mean=508 mm). In September 1995, we sexed the 

 fish again and found that the largest individual (tag no. 

 96-344C, 617 mmi had completed sex reversal and that 

 its ovary contained early vitellogenic oocytes. We exam- 

 ined these fish a final time on 17 August 1996 and found 

 that they ranged in length from 467 mm to 649 mm 

 (mean=534 mm). Two additional fish that were 622 mm 

 (tag no. 10685C) and 584 mm (tag no. 13CB03) long had 

 reversed sex, and their ovaries contained nonvitellogenic 

 oocytes. The largest fish, a male, (tag no. 13BC2E) was 



