McGovern et al.: Changes in the sex ratio and size at maturity of Mycteroperca microlepis 
801 
Table 4 
Number of sexually mature gag, Mycteroperca microlepis, females (F), males (M), and transitionals (T) taken in North Carolina, 
South Carolina, Georgia, northern Florida, and southern Florida during 18 January to 18 April 1995 when fishermen were 
required to land all gag with intact gonads (TL=total length). 
North Carolina South Carolina Georgia North Florida South Florida 
Size 
(mm TL) 
F 
M 
T 
F 
M 
T 
F 
M 
T 
F 
M 
T 
F 
M 
T 
450-499 
500-549 
— 
— 
— 
2 
— 
— 
— 
— 
— 
— 
— 
— 
— 
— 
— 
550-599 
1 
— 
— 
10 
— 
— 
— 
— 
— 
1 
— 
— 
— 
— 
— 
600-649 
3 
— 
— 
12 
— 
— 
1 
— 
— 
— 
— 
— 
3 
— 
— 
650-699 
13 
— 
— 
39 
— 
— 
16 
— 
— 
4 
— 
— 
7 
— 
— 
700-749 
37 
— 
— 
87 
— 
— 
35 
— 
— 
6 
— 
— 
6 
— 
— 
750-799 
53 
— 
— 
199 
— 
— 
113 
— 
— 
46 
— 
— 
26 
— 
— 
800-849 
64 
— 
— 
234 
— 
1 
214 
— 
— 
111 
— 
— 
86 
— 
— 
850-899 
64 
— 
— 
160 
3 
— 
148 
1 
— 
155 
— 
— 
53 
1 
1 
900-949 
23 
— 
— 
66 
1 
— 
43 
1 
— 
112 
— 
— 
27 
1 
— 
950-999 
19 
1 
— 
11 
3 
— 
16 
1 
— 
44 
18 
— 
9 
3 
— 
1000-1049 
7 
3 
— 
4 
5 
— 
10 
4 
— 
26 
33 
— 
1 
3 
— 
1050-1099 
3 
1 
— 
2 
4 
— 
7 
3 
— 
14 
27 
— 
1 
1 
— 
1100-1149 
— 
— 
— 
3 
1 
— 
— 
1 
— 
2 
9 
— 
1 
2 
— 
1150-1199 
— 
— 
— 
— 
3 
— 
1 
1 
— 
— 
3 
— 
— 
— 
— 
1200-1249 
— 
1 
— 
— 
1 
— 
— 
2 
— 
— 
1 
— 
— 
— 
— 
1250-1299 
No lengths 
2 
2 
2 
1 
Total 
287 
6 
— 
831 
21 
1 
606 
14 
— 
523 
91 
— 
221 
11 
1 
Percent 
97.9 
2.1 
— 
97.4 
2.5 
0.1 
97.7 
2.3 
— 
85.1 
14.9 
— 
94.8 
4.7 
0.5 
508 mm in 1976-82 and 517 mm in 1994-95. All gag 
>683 mm in the 1976—82 samples and those >750 mm 
in the 1994-95 samples were sexually mature. Dur- 
ing 1994-95, 266 males ( x TL=1041 mm, SD=68) 
were collected and no gag less than 875 mm was male 
(Table 5). During 1976-82, 104 males ( * TL=1041 
mm, SD=73) were collected with the smallest speci- 
men at 795 mm. The transitional specimens collected 
during 1994-95 were larger than those from 1976 to 
1982. 
The length at 50% maturity (L 50 ) was similar dur- 
ing 1978-82 (641 mm; 95% confidence interval (Cl) 
=616-658 mm) and 1994-95 (622 mm; 95% CI=611- 
631 mm (Fig. 1); however, the probit analysis with 
period and total length as independent variables 
(Pearson yy, P= 0.9953, df=27) indicated that the size 
at maturity was likely decreasing (Table 6). The nega- 
tive coefficient for period indicated that overall a 
smaller proportion of specimens in each size class 
was mature during 1976-82. The overlap in the his- 
tograms of female gag that were developing, ripe, or 
spent and females that were resting indicated that 
reproductive tissue was correctly assigned to the 
immature and resting categories (Fig. 2). 
Female gag were in spawning condition from De- 
cember 1994 through mid May 1995 on the basis of 
Table 5 
Number of mature gag, Mycteroperca mi 
during 1994-95 (TL=total length). Trans 
specimens. 
crolepis, taken 
= transitional 
Size 
(mm TL) 
Female 
Male 
Trans 
450-499 
0 


500-549 
2 
— 
— 
550-599 
16 
— 
— 
600-649 
35 
— 
— 
650-699 
121 
— 
— 
700-749 
267 
— 
— 
750-799 
650 
— 
1 
800-849 
1021 
— 
2 
850-899 
790 
7 
5 
900-949 
386 
14 
12 
950-999 
132 
46 
10 
1000-1049 
70 
82 
8 
1050-1099 
33 
68 
— 
1100-1149 
7 
28 
— 
1150-1199 
2 
15 
— 
1200-1249 
— 
5 
1 
1250-1299 
1 
— 
— 
No Lengths 
41 
1 
— 
Total 
3574 
266 
39 
Percent 
92.1 
6.9 
1.0 
