24 
Abstract — Cobia (Rachycentron Cana- 
dian) is a pelagic, migratory species 
with a transoceanic distribution in 
tropical and subtropical waters. Rec- 
reational fishing pressure on Cobia 
in the United States has increased 
substantially during the last decade, 
especially in areas of its annual in- 
shore aggregations, making this spe- 
cies potentially susceptible to overfish- 
ing. Although Cobia along the Atlantic 
and Gulf coasts of the southeastern 
United States are currently managed 
as a single fishery, the genetic composi- 
tion of Cobias in these areas is unclear. 
On the basis of a robust microsatel- 
lite data set from collections along the 
U.S. Atlantic coast (2008-09), offshore 
groups were genetically homogenous. 
However, the 2 sampled inshore ag- 
gregations (South Carolina and Vir- 
ginia) were genetically distinct from 
each other, as well as from the offshore 
group. The recapture of stocked fish 
within their release estuary 2 years 
after release indicates that some de- 
gree of estuarine fidelity occurs within 
these inshore aggregations and sup- 
ports the detection of their unique ge- 
netic structure at the population level. 
These results complement the observed 
high site fidelity of Cobias in South 
Carolina and support a recent study 
that confirms that Cobia spawn in the 
inshore aggregations. Our increased 
understanding of Cobia life history 
will be beneficial for determining the 
appropriate scale of fishery manage- 
ment for Cobia. 
Manuscript submitted 25 April 2012. 
Manuscript accepted 6 November 2013. 
Fish. Bull. 112:24-35 (2014). 
doi: 10.7755/FB.112.1.2 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necesarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Population genetics of Cobia ( Rachycentron 
canadum ): implications for fishery management 
along the coast of the southeastern 
United States 
Tanya L. Darden (contact author) 
Matthew J. Walker 
Karl Brenkert 
Justin R. Yost 
Michael R. Denson 
Email address for contact author: dardent@dnr.sc.gov 
South Carolina Department of Natural Resources 
Marine Resources Research Institute 
331 Fort Johnson Road 
Charleston, South Carolina 29412 
Cobia ( Rachycentron canadum), be- 
longing to the monotypic family 
Rachycentridae (Actinopterygii: Per- 
ciformes), is a large, pelagic, migra- 
tory species distributed throughout 
tropical and subtropical waters of 
the Atlantic, Indian, and western Pa- 
cific oceans (Shaffer and Nakamura, 
1989). The species is highly prized 
by both recreational fisheries and 
aquaculture producers as excellent 
table fare. Within the United States, 
this recreationally and commercially 
important fish species occurs along 
the southeastern Atlantic and Gulf 
of Mexico coasts. Cobia has histori- 
cally been managed by the South At- 
lantic Fishery Management Council 
and Gulf of Mexico Fishery Manage- 
ment Council as a single reproduc- 
tive stock on the basis of minimal 
data from tag and recapture research 
and mitochondrial fragment analysis 
(Hrincevich, 1993). Most early life 
history information on Cobia comes 
from aquaculture research, and lit- 
tle is known about its natural life 
history. 
In the spring and early summer 
months, Cobias in the western North 
Atlantic are thought to migrate with 
warming waters from Florida to the 
Chesapeake Bay (Shaffer and Na- 
kamura, 1989). During this puta- 
tive northward migration, Cobias 
enter high salinity bays and estuar- 
ies, including Port Royal Sound and 
St. Helena Sound in South Carolina 
(SC), Pamlico Sound in North Caroli- 
na (NC; Smith, 1995), and the Chesa- 
peake Bay (Shaffer and Nakamura, 
1989). Cobias have been reported 
to spawn from April to Septem- 
ber (Smith, 1995; Lotz et ah, 1996; 
Burns et al.; 1 Brown-Peterson et ah, 
2001). Regional peaks in spawning 
correlate with their proposed annual 
migration from Florida to Massachu- 
setts, occurring in May along the SC 
coast (Shaffer and Nakamura, 1989; 
Burns et al. 1 ), June in NC (Smith, 
1995), and during June and July in 
the Chesapeake Bay region (Joseph 
et al., 1964). 
One aspect of Cobia biology that 
has only recently been investigated 
is their annual inshore aggregations 
that occur in high-salinity estuaries. 
The nature of these aggregations has 
been hypothesized to be associated 
with either feeding or reproduction 
(Joseph et al., 1964; Richards, 1967; 
Hassler and Rainville, 1975; Smith, 
1995; Lotz et al., 1996; Burns et al. 1 ), 
1 Burns, K., C. Neidig, J. Lotz, and R. Over- 
street. 1998. Cobia (Rachycentron 
canadum) stock assessment study in the 
Gulf of Mexico and in the south Atlan- 
tic. Mote Marine Laboratory Technical 
Report No. 571, 108 p. [Available from 
Mote Marine Laboratory, 1600 Thomp- 
son Parkway, Sarasota, FL 342236.] 
