658 
Fishery Bulletin 99(4) 
Predicted TL at age for males and females (Figs. 6 and 
7) generated with the above equations illustrated rapid 
and roughly equivalent growth to an age of approximately 
8-10 yr after which the growth curves diverge. Differential 
growth between males and females was further demon- 
strated with likelihood ratio tests which indicated signifi- 
cant differences in (x 2 =13.05; df=l,2979; P<0.0003) and 
k (% 2 =7. 16; df=l, 2979; P<0. 0075). No significant difference 
was detected in t 0 ( x 2= 1-34; df=l,2979; P<0.247). Owing to 
the large variability in observed TL at age (Fig. 6), TL was 
a poor estimator of red snapper age within the range of TL 
encountered in our sampling efforts. 
Discussion 
Otolith annuli as indicators of age in years have been 
validated for many freshwater and marine fish species, 
including the Australian lutjanids L. adetii and L. quin- 
quelineatus (Newman et al., 1996) and L. argentimacula- 
tus, L. bohar, L.carponotatus, L. erythropterus, L. gibbus, 
L. johnii, L. malabaricus , L. monostigina , L. rivulatus, L. 
sebae, and L. vitta (Cappo et al., 2000). Previous studies of 
red snapper have used scales (Moseley, 1966; Wade, 1981), 
otoliths (Futch and Bruger, 1976; Szedlmayer and Shipp, 
1994; Render, 1995; Manooch and Potts, 1997; Patterson, 
Table 1 
Average percent error (APE), coefficient of variation (CV), 
and index of precision (D) differences in red snapper (Lut- 
janus campechanus ) otolith annulus counts for two read- 
ers on first and second readings, n = 3791. 
l sl reading 
2 nd reading 
APE 
3.736 
0.0934 
CV 
0.045 
0.0011 
D 
0.032 
0.0008 
0 
73.96% 
99.29% 
±1 
23.27% 
0.61% 
±2 
2.24% 
0.08% 
> ±3 
0.53% 
0.02% 
1999), scales and otoliths (Nelson and Manooch, 1982) and 
scales, otoliths, and vertebrae (Bortone and Hollingsworth, 
1980) to estimate ages. Among these, early attempts to val- 
idate age estimation from circuli of scales and annuli of 
otoliths have suffered from two shortcomings: 1) a small 
sample size and 2) a paucity of individuals over age 10 
yr. Nevertheless, they have produced a general consensus 
