WENNER ET AL.: LIFE HISTORY OF BLACK SEA BASS 



DORSAL 



ANTERIOR 



i 



POSTERIOR w 



NUCLEUS 



CENTRAL FIELD 



VENTRAL 



— length- 



Figure 4.— Schematic representation of the left sagitta in young of the year Centropristis striata showing 

 the orientation and direction of growth ring-counts in the central opaque zone, a = anterior, d = dorsal, p 

 = posterior, v = ventral. 



line because grinding did not expose all rings equally 

 in the central zone. Also, in some instances, count- 

 ing was halted at a distinct mark, such as a ring 

 more distinctive than others, and we followed this 

 mark around the sagitta to a site where rings were 

 again visible and resumed counting. The number of 

 rings in the central zone varied because of the oto- 

 lith asymmetry and with the direction of the count 

 (Table 2). For example, we obtained the following 

 counts from the central primordium in one specimen 

 (number 9 of Table 2): 90 rings to the dorsal edge 

 of the central field (d of Fig. 4); 95 rings to the ven- 

 tral edge (v of Fig. 4); 129 rings to the posterior edge 

 (p of Fig. 4). 



Since marginal increments on the otoliths should 

 approach zero during the time of annulus formation, 

 we calculated their monthly means to determine if 

 one opaque band was laid down during each year 



on the sagittae of C. striata. Generally, a single an- 

 nulus was formed during April and May in all age 

 groups (Fig. 5). We found that the ring was 

 deposited unevenly around the sagitta, with the dor- 

 sal margin of the annulus being the last to be 

 completed. 



We identified 10 age groups in the South Atlan- 

 tic Bight population of C. striata, which exceeded 

 the previous reports of 7 (Cupka et al. 1973 5 ) and 

 8 (Mercer 1978) groups. Observed mean lengths and 

 weights increased with age; however, small sample 

 sizes in ages 8 through 10 masked this trend (Table 

 3). Regressions of weight on length (TL and SL) and 

 length on length are in Table 4. 



5 Cupka, D. M., R. K. Dias, and J. Tucker. 1973. Biology of 

 black sea bass, Centropristis striata from South Carolina waters. 

 Unpubl. manuscr. South Carolina Wildlife and Marine Resources 

 Department, P.O. Box 12559, Charleston, SC 29412. 



Table 2.— Data from Centropristis striata examined for daily growth rings. Refer to Figure 2 for otolith morphology and terms 

 (d, v, p, and a) used in the counts. Numbers in parentheses are ranges of several counts; dashes indicate no counts made. 



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