Crabtree and Bullock: Life history of Mycteroperca bonaci 
747 
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Figure 9 
Age (yr) 
The percent frequency of occurrence of (A) cortical alveolar oocytes and (B) vitellogenic oocytes in black grouper. 
Mycteroperca bonaci , ovaries as a function of total length (mm; n 
=772) and age (years; n=609). 
greater than those of Manooch and Mason, but their 
estimates for these age classes fall below not only 
our predicted lengths but also their predicted lengths. 
The von Bertalanffy growth model parameters esti- 
mated by Manooch and Mason were = 1,352 mm, 
greater than our estimate of Lj= 1,306 mm, and K = 
0.1156, less than our estimate of K = 0.169. 
Black grouper, though not as large as jewfish or 
warsaw grouper, are among the largest species of 
grouper, and it is not surprising that they attain ages 
over 30 years. Estimates of the longevity of other 
grouper species are similar to our estimates for black 
grouper. Hood and Schlieder (1992) and Collins et 
al. (1987) estimated a maximum age of 21-22 years 
for gag, Bullock et al. (1992) estimated a maximum 
age of 37 years for jewfish ( E . itajara), Bullock and 
Murphy ( 1994) estimated a maximum age of 28 years 
for yellowmouth grouper, Manooch and Mason (1987) 
reported that warsaw grouper ( E . nigritus) reach 41 
years, and Moe (1969) reported a red grouper ( E . 
morio) 25 years old. The growth rate (K-0. 169/year) 
of black grouper is similar to that estimated for gag 
(K=Q. 166/year, Hood and Schlieder, 1992), but is 
greater than the growth rates estimated for many 
other grouper species: jewfish K = 0.126/year (Bul- 
lock et al., 1992), yellowmouth grouper K - 0.08/year 
(Bullock and Murphy, 1994), and warsaw grouper 
K = 0.054/year (Manooch and Mason, 1987). 
Sexual maturation and transition 
Our histological analysis of black grouper gonads is 
consistent with the diagnostic criteria of Sadovy and 
Shapiro (1987) for a monandric protogynous her- 
maphrodite. Furthermore, the absence of small males 
and a sex ratio highly skewed towards females are 
consistent with our diagnosis of protogynous her- 
maphroditism. Although the length and age distri- 
butions of males and females overlapped, males oc- 
cupied the largest and oldest length and age classes 
and were unrepresented in smaller and younger 
length and age classes (Figs. 1 and 6). This is an 
important difference between black grouper and 
Nassau grouper (Epinephelus striatus), which has 
recently been diagnosed as a gonochorist with po- 
tential for sex change (Sadovy and Colin, 1995). In 
