Kolmos et al.: Temporal changes in the life history of Hyporthodus niveatus off North and South Carolina 
313 
comparisons of the age distribution and the median age 
of females and males (transitional specimens excluded) 
from all years also indicate protogyny (Fig. 5). Of the 16 
fish that were older than age 20, 31% were female and 
69% were male. The median age of females was 6 years, 
half the median age of 12 years for males. 
Maturity and sex composition 
We examined histological sections of gonad tissue 
from 1566 snowy grouper collected during 2008-2012, 
making our total number of histological samples 2324 
when adding historical data from Wyanski et al. (2000). 
Correct assignment of females from 
the period 2008-2012 to the immature 
and regenerating reproductive phases 
was indicated by the presence of only 
5 specimens in the regenerating phase 
(457-517 mm TL) that were smaller 
than the total length (525 mm TL) of 
the smallest definitely mature speci¬ 
men (i.e., specimen in the developing, 
spawning-capable, or regressing phases). 
There were 19 specimens <525 mm TL 
(1.3% of 1467 females examined) that 
could not be definitively categorized as 
immature or regenerating. 
Female size and age at maturity were 
assessed for the overall data set (i.e., all 
gears and all years) and by period. The 
smallest mature female was 457 mm TL, 
whereas the largest immature female 
was 787 mm TL. In the observed data, 
gonads in a reproductive phase indica¬ 
tive of sexual maturity were present in 
4% of females at age 3, in 44% at age 
5, in 75% at age 7, and in 100% at ages 
>13 years. The L 50 mat was 578 mm TL 
(logit link: 77=1853, 95% confidence 
interval [Cl] 475-702 mm TL). Because 
of low sample sizes, data from the 1980s 
and 1990s were combined to conduct a 
temporal analysis of L 50 mat . There was 
a significant increase in L 50 mat from 
529 mm TL (logit link: 77=564, 95% Cl 
314—893 mm TL) in the 1980s and 1990s 
to 596 mm TL (logit link: 77 = 1289, 95% 
Cl 474-747 mm TL) in the 2000s (% 2 test: 
P<0.001; Fig. 6A). The overall youngest 
mature female was age 3, whereas the 
oldest immature female was age 13. 
The A 50 mat was 5.5 years (Cauchy link: 
77=1637,’ 95% Cl 4.0-7.6 years). To con¬ 
duct a temporal analysis of A 50 mat , data 
from the 1980s and 1990s were again 
combined because of low sample sizes. 
There was a significant increase in 
A 5 o mat from 5.0 years (logit link: 77=425, 
95% Cl 3.2-7.6 years) in the 1980s and 
1990s to 5.8 years (logit link: 77=1212, 95% Cl 3.2-7.6 
years) in the 2000s (% 2 test: P<0.001) (Fig. 6B). 
Trends in length and age at sex transition to male were 
examined for the overall data set and by period. The over¬ 
all estimates of L 50 ma]e and A 50 male for all gear types were 
886 mm TL (logit link: 77=2038,’95% Cl 688-1143 mm TL) 
and 17.0 years (probit link: 77=1755,95% Cl 14.0-21.9 years), 
respectively. Estimates of L 50 male were similar between 
periods, 880 mm TL in the 1980s and 1990s combined 
(logit link: /7=657, 95% Cl 593-1309mm) and 894 mm TL 
in the 2000s (logit link: 77=1360, 95% Cl 633-1269mm TL; 
X 2 test: P=0.52). There was a decrease in A 50 male from 
18.0 years (logit link: 77=473, 95% Cl 11.8-27.8 years) in 
