308 
National Marine 
Fisheries Service 
NQAA 
Abstract —The snowy grouper ( Hyport- 
liodus niveatus) is a commercially valu¬ 
able deepwater grouper that is managed 
by the South Atlantic Fisheries Man¬ 
agement Council. This study updates 
life history parameters of snowy grou¬ 
per caught off North and South Carolina 
from 1979 through 2012 by commercial 
and research vessels (number of fish 
sampled: 5314). On the basis of samples 
collected in 2008-2012, size at age has 
decreased since the 1990s, and size and 
age at maturity have increased in com¬ 
parison with data pooled from the 1980s 
and 1990s. However, no significant 
changes in size and age at sex transition 
were noted between the 2000s and the 
1980s-1990s. This study confirmed that 
snowy grouper are protogynous and 
that the spawning season in this region 
is broader than previously reported. In 
addition, we found that spawning fre¬ 
quency varied with size and age and 
was influenced by lunar phase, with 
most spawning occurring around the 
new moon. Results indicate that snowy 
grouper in the study area have started a 
slow recovery from overfishing. 
Manuscript submitted 21 November 2018. 
Manuscript accepted 30 September 2019. 
Fish. Bull. 117:308-321 (2019). 
Online publication date: 24 October 2019. 
doi: 10.7755/FB. 117.4.4 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Fishery Bulletin 
established in 1881 •<?> 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Temporal changes in the life history of 
snowy grouper (Hyporthodus niveatus) off 
North and South Carolina, and factors that 
influence spawning dynamics 
Kevin J. Kolmos (contact author) 
David M. Wyanski 
D. Byron White 
Paulette P. Mikell 
Email address for contact author: kolmosk@dnr.sc.gov 
Marine Resources Research Institute 
South Carolina Department of Natural Resources 
P.O. Box 12559 
Charleston, South Carolina 29422 
The snowy grouper (Hyporthodus 
niveatus ) is a commercially valuable 
deepwater species that occurs in the 
western Atlantic Ocean from Massa¬ 
chusetts to Brazil, including Bermuda, 
the Bahamas, Cuba, and the Gulf of 
Mexico (Heemstra et al., 2002), with 
occasional occurrence off the east¬ 
ern coast of Canada (Scott and Scott, 
1988). This species is thought to be a 
protogynous hermaphrodite (Moore 
and Labisky, 1984; Wyanski et al., 
2000), but conclusive evidence has 
not been produced. Along the coast of 
the southeastern United States, adult 
snowy grouper are predominantly 
found on the upper continental slope 
at depths of 137-259 m, whereas juve¬ 
niles are more common at shallower 
depths (Moore and Labisky, 1984). 
Wyanski et al. (2000) noted a positive 
correlation between total length (TL) 
and water depth off North and South 
Carolina. Most fishing for this species 
occurs in habitats characterized by 
rocky ledges, cliffs, and swift currents 
(Matheson and Huntsman, 1984). Off 
the southeastern United States, snowy 
grouper are captured primarily in com¬ 
mercial fisheries with bottom longlines 
and snapper reels (Parker and Mays, 
1998; Wyanski et al., 2000). 
Snowy grouper are prone to being 
overfished (Huntsman et al., 1999) 
because they are slow growing (Mathe¬ 
son and Huntsman, 1984; Moore and 
Labisky, 1984; Wyanski et al., 2000) 
and late maturing, between the ages 
of 3 and 8 years (Moore and Labisky, 
1984; Wyanski et al., 2000). Estimates 
of their maximum age range from 27 
to 29 years (Moore and Labisky, 1984; 
Wyanski et al., 2000). This range is 
reasonable, given the maximum age of 
27 years reported in a project report 
for an age validation study (Harris 1 ) 
that measured radiocarbon ( 14 C), from 
atmospheric testing of nuclear weapons 
during 1950-1970, in sagittal otolith 
cores of 21 snowy grouper examined 
by Wyanski et al. (2000). Results of 
the validation study were accepted as 
the best available evidence during the 
1 Harris, R J. 2013. Validation of ages for 
species of the deepwater snapper/grouper 
complex off the southeastern coast of the 
United States. Southeast Data, Assess¬ 
ment, and Review SEDAR36-RD07, 12 p. 
[Available from website.] 
