Kolmos et al.: Temporal changes in the life history of Hyporthodus niveatus off North and South Carolina 
309 
most recent stock assessment (SEDAR, 2013), although 
the study had the limitations 1) of not having a reference 
chronology from the study area, the southeastern United 
States, and 2) of small sample sizes during the years that 
the rate of increase for 14 C in the surface waters of the 
oceans was at its maximum. Periodicity of increment for¬ 
mation was determined indirectly by Wyanski et al. (2000) 
by using marginal increment analysis. 
Landings varied widely during 1981-2005, mostly 
because of the flexibility of commercial fishermen to shift 
between fisheries (e.g., from bottom longline for deepwater 
reef fish to pelagic longline for swordfish in 1984-1985) to 
optimize earnings (Low et al. 2 ). This period was charac¬ 
terized by minimal fisheries regulation, given that there 
were no regulations affecting snowy grouper through 1988 
and that the regulations implemented by the South Atlan¬ 
tic Fisheries Management Council after 1988 (e.g., trawl¬ 
ing ban, depth restriction for bottom longlining, annual 
quota, and trip limit) had minimal impact on catches of 
this species (SEDAR, 2013; SAFMC 3 ). In 2009, the South 
Atlantic Fisheries Management Council allocated 95% 
of the total allowable catch to the commercial sector 
through Amendment 15B to the fishery management 
plan for snapper and grouper off the coasts of North 
Carolina, South Carolina, Georgia, and Florida (Federal 
Register, 2009). Two assessments of the snowy grouper 
population have been conducted by using the Southeast 
Data, Assessment, and Review process: a benchmark 
assessment on snowy grouper in 2004 (SEDAR, 2004) 
and a standard assessment in 2013 (SEDAR, 2013). The 
results of the assessment completed in 2004 indicate 
that the population off the southeastern United States 
was overfished and was undergoing overfishing, a status 
that resulted in further reductions in commercial quotas 
and trip limits to reduce fishing mortality starting in 
2006 (SEDAR, 2013). The latest assessment, conducted 
in 2013, determined that the population was not experi¬ 
encing overfishing but remained overfished. 
Nearly 2 decades have elapsed since the life history of 
the population of snowy grouper along the Atlantic coast 
of the southeastern United States was investigated by 
Wyanski et al. (2000) by using samples collected primarily 
from the commercial fishery during 1979-1995. By com¬ 
paring characteristics of the population between the 1980s 
and 1990s, Wyanski et al. (2000) documented a few indi¬ 
cators of an overfished population, and those signals were 
confirmed by the benchmark stock assessment in 2004 
(SEDAR, 2004). The leading indicators were 1) significant 
increases in size at age, 2) predominance (81%) of fish at 
ages 1-6 in bottom longline samples collected in the 1990s, 
the majority (56%) of which were immature females, and 
3) a decrease in mean length of fish landed in the bottom 
2 Low, R. A., D. Theiling, and E. B. Joseph. 1987. South Carolina 
marine fisheries, 1977-1986. South Carolina Wildl. Mar. Res. 
Dep., Tech. Rep. 67, 78 p. [Available from website.] 
3 SAFMC (South Atlantic Fishery Management Council). 2019. 
Snapper grouper—fishery management plan. [Available from 
website, accessed February 2019.] 
longline fishery from 65-80 cm TL to 50-60 mm TL with¬ 
out any notable change in depth of capture. 
Updates of life history parameters for snowy grou¬ 
per are needed to fill existing information gaps and pro¬ 
vide critical data for stock assessments in support of the 
sustainable management of this species. Reproductive 
parameters such as sex composition need further inves¬ 
tigation because of a small sample size in previous stud¬ 
ies; the analysis by Wyanski et al. (2000) included only 82 
specimens collected during 1993-1994, none of which were 
>900 mm TL. The results of this study provide updated 
estimates of life history parameters, such as size at age, 
age at maturity, spawning seasonality, and age at sex 
transition. We discuss the potential effects of manage¬ 
ment measures implemented since 2006 on the life his¬ 
tory parameters of the population of snowy grouper off 
the southeastern United States. Our histological samples 
were also examined for evidence to confirm that the snowy 
grouper is a protogynous hermaphrodite and to investi¬ 
gate the effect of age, size, and lunar phase on spawning. 
Materials and methods 
Sampling 
During 1979-2012, snowy grouper were obtained from 
commercial boats, research vessels, and recreational char¬ 
ter boats, primarily off North and South Carolina. Fishery- 
independent samples of reef fish species were collected 
during cruises conducted as part of the Marine Resources 
Monitoring Assessment and Prediction (MARMAP) pro¬ 
gram, the Southeast Area Monitoring and Assessment 
Program—South Atlantic (SEAMAP-SA), and the South¬ 
east Fishery-independent Survey (SEFIS) with bottom 
longlines, Kali poles (an off-bottom longline; Russell et al., 
1988), snapper reels, rods and reels, and chevron traps 
(Collins, 1990; Smart et al. 4 ). These 3 sampling efforts rep¬ 
resent a collaborative survey known as the Southeast Reef 
Fish Survey, which samples fish on natural reefs from 
Cape Hatteras, North Carolina, to St. Lucie Inlet, Florida. 
Kali poles were used only during sampling in the 1980s, 
and sampling prior to 2010 was conducted solely by the 
MARMAP program. The SEAMAP-SA and SEFIS began 
sampling in 2008 and 2010, respectively, and use chevron 
traps and rods and reels to complement sampling done by 
the MARMAP program with the same gears. 
In the years since the study by Wyanski et al. (2000), the 
MARMAP program acquired specimens of snowy grouper 
in 2008-2009 through a Cooperative Research Program 
grant it received from the National Marine Fisheries Ser¬ 
vice in partnership with a commercial bottom longline fish¬ 
erman. From this fisherman’s vessel, 1078 snowy grouper 
4 Smart, T. I., M. J. M. Reichert, J. C. Ballenger, W. J. Bubley, and 
D. M. Wyanski. 2016. Overview of sampling gears and standard 
protocols used by the Southeast Reef Fish Survey and its part¬ 
ners. Southeast Data, Assessment, and Review SEDAR50-RD20, 
14 p. [Available from website.] 
