397 
Abstract — We documented inshore 
spawning of the recreationally impor- 
tant cobia ( Rachycentron canadum) 
in Port Royal Sound (PRS) and St. 
Helena Sound (SHS), South Caro- 
lina, during the period from April 
to June in both 2007 and 2008. His- 
tological analysis of ovaries confirmed 
the presence of actively spawning 
females inshore, and gonadosomatic 
index (GSI) values from females col- 
lected inshore (mean=7.8) were higher 
than the values from females caught 
offshore (mean=5.6); both of these 
mean values indicate that spawn- 
ing occurred locally. Additionally, 
we conducted an ichthyoplankton 
survey in 2008 and found cobia eggs 
and larvae as far as 10 and 15 km 
inshore from the mouths of SHS and 
PRS, respectively. A study of egg 
development that we conducted in 
2007 and 2008 using hatchery-reared 
cobia eggs provided descriptions of 
embryological development of cobia. 
Comparison of visual and quantitative 
characteristics of the field-collected 
eggs with those of the hatchery-reared 
eggs allowed positive identification of 
eggs collected in plankton samples. 
The ages of field-collected eggs and 
presence of females with hydrated 
oocytes in PRS and SHS observed 
in our ichthyoplankton survey and 
histological analysis indicated that 
wild cobia spawn in the afternoon and 
early evening. The inshore migration 
of cobia from April to June, the pres- 
ence of actively spawning females, 
significantly higher GSI values, and 
the collection of eggs inside PRS and 
SHS all confirm that these estuaries 
provide spawning habitat for cobia. 
Because of the potential for heavy 
exploitation by recreational anglers 
as cobia move inshore to spawn in 
South Carolina, current management 
strategies may require review. 
Manuscript submitted 12 November 2011. 
Manuscript accepted 30 July 2012. 
Fish. Bull. 110:397-412 (2012). 
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. 
Inshore spawning of cobia ( Rachycentron canadum ) 
in South Carolina 
Lyndsey S. Lefebvre (contact author ) 1 
Michael R. Denson 2 
Email address for contact author: lyndsey.lefebvre@noaa.gov 
1 Grice Marine Laboratory 
College of Charleston 
205 Fort Johnson Road 
Charleston, South Carolina 29412 
Present address: Fisheries Ecology Division 
Southwest Fisheries Science Center 
National Marine Fisheries Service 
110 Shaffer Road 
Santa Cruz, California 95060 
2 Marine Resources Research Institute 
South Carolina Department of Natural Resources 
217 Fort Johnson Road 
Charleston, South Carolina 29412 
Cobia ( Rachycentron canadum) is 
a migratory, euryhaline benthope- 
lagic species distributed worldwide 
in tropic, subtropic, and warm tem- 
perate waters, except in the eastern 
Pacific (Briggs, 1960). In the United 
States, cobia are found throughout 
the Gulf of Mexico and along the 
Atlantic coast from Florida to Mas- 
sachusetts (Shaffer and Nakamura, 
1989). Cobia are moderately long 
lived, with a maximum reported age 
of 15 years (Shaffer and Nakamura, 
1989), and have fast growth rates, 
with both sexes reaching sexual 
maturity by age 2 (males 60 cm fork 
length [FL] ; females 80 cm FL [Smith, 
1996; Burns et al. 1 ])- Currently in the 
United States, most commercial land- 
ings of cobia result from incidental 
catch in other fisheries (Shaffer and 
Nakamura, 1989). Cobia are sought 
recreationally throughout their range, 
and the majority of the annual catch 
for cobia in the United States comes 
from the recreational fishery: 957 of 
the combined 1070 metric tons (t) from 
1 Burns, K. M., C. Neidig, J. Lotz, and R. 
Overstreet. 1998. Cobia (Rachycentron 
canadum ) stock assessment study in the 
Gulf of Mexico and in the South Atlan- 
tic. Final Rep., MARFIN Coop. Agree- 
ment NA57FF0294 to NMFS (NOAA), 
108 p. Mote Marine Laboratory, 1600 
Thompson Parkway, Sarasota, FL 34236. 
commercial and recreational land- 
ings in 2010 (National Marine Fish- 
eries Service [NMFS 2 ]). The current 
fishery management plan for cobia, 
which imposes a bag limit of 2 fish 
per person per day and a minimum 
FL of 84 cm (33 in), was established 
by the Gulf of Mexico Fishery Man- 
agement Council (GMFMC) and South 
Atlantic Fishery Management Coun- 
cil (SAFMC) in 1983 to conserve a 
population considered overexploited 
at that time (SAFMC and GMFMC 3 ). 
The restrictions were enacted under 
the assumptions that cobia are widely 
dispersed, are primarily commercial 
bycatch, constitute a recreational fish- 
ery, and compose a single population 
in the United States. These restric- 
tions were meant to reduce catches 
and allow females the opportunity to 
reproduce before entering the fish- 
ery. Data on regional fishing effort 
and catch indicate fishing pressure 
2 NMFS (National Marine Fisheries Ser- 
vice.) 2012. Personal commun. Fish- 
eries Statistics Division, Silver Spring, 
MD. 
3 SAFMC and GMFMC. 1983. Fishery 
management plan, final environmental 
impact statement, regulatory impact 
review, final regulations for coastal 
migratory pelagic resources (mackerels), 
321 p. SAFMC, 4055 Faber Place, Suite 
201, North Charleston, SC 29405. 
