Crabtree and Bullock: Life history of Mycteroperca bonaci 
743 
black in males (Fig. 10, A-C). The jet 
black pigmentation of the pectoral fin 
was most apparent on the medial 
side. The dorsal interspinous mem- 
brane of females was yellow to dusky 
(Fig. 10D). In males, this membrane 
was usually dark black but was oc- 
casionally yellow or yellowish with 
black tips. Because this membrane 
can be yellow in both males and fe- 
males, the coloration of this fin was 
the least reliable indicator of sex. The 
distal one-third of the soft dorsal fin 
was dark black in both sexes and was 
not useful in determining sex. 
Seasonality of 
gonad development 
The frequencies of the four oocyte 
stages we counted in black grouper 
ovaries had a seasonal pattern that 
was repeated in both 1995 and 1996 
( Fig. 1 1, A and B ). Vitellogenic oocytes 
were present in greatest number in 
January-March in both 1995 and 
1996 and were present in all months 
except September-November 1996. 
Cortical alveolar stage oocytes were 
also present in all months except 
September-November 1996 and were 
most abundant during December- 
April. Primary growth stage oocytes 
were present during all months and 
made up at least 55% of the total 
number of oocytes present. Oocytes 
in the final stages of maturation were 
not abundant, but they were most 
common during December-May (Fig. 
11B). We examined six females with 
hydrated ovaries: one was caught 
during October, one in December, and 
four in March. The ovaries from these 
Table 2 
Average observed and predicted total lengths (mm) for sexed and unsexed 
black grouper, Mycteroperca bonaci, and average observed lengths for females 
and males. The average observed length at age includes some seasonal growth 
that occurred after the formation of the final annulus. Values in parentheses 
are standard error and sample size. 
Age 
(yr) 
Sexed and unsexed 
Females 
Males 
Average 
observed 
Predicted 
Average 
observed 
Average 
observed 
0 
155 (1) 
159 
155 (1) 
1 
338 (8.7;41) 
337 
339(8.9; 39) 
2 
486 (5.7;113) 
487 
486(5.7:112) 
3 
606 (5.7;136) 
614 
607 (5.7;134) 
4 
733 ( 5.5; 155 ) 
722 
734(5.7:147) 
5 
814 (5.8; 1 13 ) 
813 
814 (6. 1;97) 
6 
871 (7.7;70) 
889 
857 (10.2;41) 
947 (1) 
7 
972 (9.1;40) 
954 
966 (13.6;20) 
1062 (1) 
8 
1008(11.6;39) 
1009 
998 (20.5:15) 
1006 (46.0;2) 
9 
1038(12.3:31) 
1055 
1024 (19.8;14) 
1058 (1) 
10 
1074 (12.3;16) 
1094 
1078 (14.6;5) 
1167(1) 
11 
1116(13.1:33) 
1127 
1147 (27.0;10) 
1130(22.8:5) 
12 
1138(14.4;21) 
1155 
1131 (29.0;9) 
13 
1164(11.6;11) 
1178 
1182(16.0:6) 
1172(1) 
14 
1175(30.6;11) 
1198 
1192(18.5:2) 
1222 (30.5;2) 
15 
1239 (14.4;7) 
1215 
1213 (1) 
1266 (26.0;3) 
16 
1165(10.5;2) 
1229 
17 
1244 (21.2;6) 
1241 
1270 (1) 
1283 (47.5;2) 
18 
1252 (30.3;10) 
1251 
19 
1226 (35.5:6) 
1260 
1285 (1) 
20 
1248 (12.9;9) 
1267 
1220 (1) 
21 
1264 (20.2;15) 
1273 
1195(1) 
1315 (38.7;4) 
22 
1278(29.6:5) 
1278 
23 
1298 (27.3;6) 
1283 
1275 (1) 
1326 (68.5;2) 
24 
1320 (26.6;5) 
1286 
1370(1) 
25 
1307 (72.2;4) 
1289 
1390 (128.0:2) 
26 
1305 (44.5;4) 
1292 
27 
1309 (23.3;7) 
1294 
1291 (38.3;4) 
28 
1300 (1) 
1296 
29 
1349 (28.3;3) 
1298 
1349 (28.3;3) 
30 
1307 (55.9;3) 
1299 
31 
1350 (1) 
1300 
1350 (1) 
32 
1301 
33 
1376 (51.0;2) 
1302 
1427(1) 
grouper contained a group of 
vitellogenic oocytes that ranged from 0.5 to 0.7 mm 
in diameter and a clutch of hydrated oocytes that 
ranged from 0.8 to 1.2 mm in diameter (Fig. 12). Most 
of the oocytes <0.2 mm in diameter, which we did 
not measure, were primary growth stage or cortical 
alveolar stage oocytes. Postovulatory follicles were 
not recognized in any female examined. 
Females with the greatest GSIs (>5) were captured 
during February-March (Fig. 13). Male GSIs (range 
0.086-0.399, n=43) were generally much less than fe- 
male GSIs (range 0.032-10.108, n=201) and had no 
Table 3 
Parameter estimates for the von Bertalanffy growth model 
for black grouper, Mycteroperca bonaci, collected from the 
waters of South Florida. Values in parentheses are stan- 
dard errors. 
n L m (mrn) K t 0 adjusted r 2 
927 1306.2 0.169 -0.768 0.941 
(8.05) (0.0037) (0.0640) 
