318 
Fishery Bulletin 117(4) 
Table 5 
Proportion of snowy grouper (Hyporthodus niveatus) caught off North and 
South Carolina that were male, by total length and period. Specimens were col¬ 
lected during the spawning season (April-September) in 3 periods: 1982-1985, 
1993-1994, and 2008-2012. Data were combined for 3 gear types: Kali pole, 
long bottom longline, and short bottom longline. Transitional specimens were 
considered males because they likely would have spawned as males in their 
next spawning season. u=number of fish examined. 
Total 
length (mm) 
1980s 
1990s 
2000s 
n 
Proportion 
male 
n 
Proportion 
male 
n 
Proportion 
male 
401-500 
i 
0.00 
501-600 
6 
0.00 
23 
0.00 
85 
0.00 
601-700 
32 
0.00 
33 
0.00 
302 
0.01 
701-800 
40 
0.00 
16 
0.06 
267 
0.03 
801-900 
29 
0.38 
3 
0.00 
97 
0.32 
901-1000 
26 
0.73 
0 
0.00 
34 
0.62 
1001-1100 
6 
0.83 
0 
0.00 
7 
0.86 
Table 6 
Proportion of adult female (active and inactive) snowy grouper (Hyporthodus niveatus) that were 
spawning daily, by 100-mm bin for total length. Specimens were collected during spawning season 
(April-September) off North and South Carolina in 1979-2012. Spawners had at least one indicator 
of imminent or recent spawning (i.e., oocyte maturation, ovulated eggs, or postovulatory complexes). 
Sampling period is the time (in days) from which representative samples of data were taken. Values 
of spawning proportion have been proportionally reduced to a 24-h period. 
Total length 
bin (mm) 
Adult 
females ( n ) 
Spawning 
proportion 
(24 h) 
Sampling 
period (d) 
Spawning 
season 
duration (d) 
Spawning 
interval (d) 
No. 
batcl 
501-600 
130 
0.06 
178 
139 
17.1 
8 
601-700 
326 
0.13 
178 
153 
8.0 
19 
701-800 
325 
0.14 
178 
177 
7.0 
25 
801-900 
94 
0.17 
175 
163 
6.0 
27 
>901 
26 
0.18 
171 
129 
5.4 
24 
Total 
901 
0.13 
152 
7.8 
19 
The spawning seasonality observed in our study is 
broader than that previously reported for the study area 
and varies with size and age. That 5 specimens with 
spawning indicators were collected from October 2008 
through March 2009 reveals that at least some snowy 
grouper can have a longer spawning season than the 
season of April-September reported by Wyanski et al. 
(2000). Spawning in October also was reported by Kowal 
(2010), on the basis of capture of snowy grouper with 
mature oocytes (i.e., undergoing oocyte maturation) in 
south Florida and the Florida Keys. It remains unknown 
if spawning in the fall and winter occurs regularly. 
Spawning by smaller and younger fish (<600 mm TL 
and <5 years) tended to occur later in the season and 
for a shorter period than spawning by larger and older 
fish (Fig. 7). Larger and older (701-900 mm TL and >5 
years) individuals had a longer spawning season, and a 
high proportion of them were spawning throughout the 
season; therefore, they can produce more batches within 
the spawning season. 
This information is essential for accurate estimates of 
reproductive potential in the population of snowy grouper 
off North and South Carolina and indicates that the larger, 
older females are of greatest importance in reproductive 
output of this population. Although the spawning propor¬ 
tion increased as individuals grew larger, the duration of 
the spawning season decreased at sizes >801 mm TL, a 
possible indication of female preparation for sex transition. 
