Life History of Cobia, Rachycentron canadum 
(Osteichthyes: Rachycentridae), in North Carolina Waters 
Joseph W. Smith 
National Marine Fisheries Service 
Southeast Fisheries Science Center 
Beaufort Laboratory 
101 Fivers Island Road 
Beaufort, North Carolina 28516-9722 
ABSTRACT . — Cobia ( n = 416) were collected primarily along the 
central North Carolina Atlantic coast from recreational anglers between 
1983 and 1994. Males ( n = 174) ranged up to 136-cm fork length 
(FL) and 32.0 kg, and females ( n = 182) up to 142-cm FL and 
32.2 kg. Most cobia greater than 100-cm FL were females. Ages 
of cobia (to age 14) were estimated by counting opaque zones on 
cross-sectioned sagittal otoliths. Von Bertalanffy growth parameter 
(k) estimates were 0.37 for males and 0.24 for females. Adult co- 
bia occurred in major sounds and coastal Atlantic waters of North 
Carolina from May through July, and in nearshore oceanic waters 
through fall. Cobia may overwinter between Cape Fear and Cape 
Canaveral at depths of 30-75 m. Cobia fed chiefly on demersal 
crustaceans and fishes in the study area. Cobia may be one of the 
few teleosts that regularly consumed small elasmobranchs. Male cobia 
were sexually mature at 60-65-cm FL (age 2), and females at 80- 
cm FL (age 2). Cobia spawned May through July along the North 
Carolina coast, and ocean waters adjacent major coastal inlets were 
probable sites for cobia spawning activity. 
Cobia, Rachycentron canadum, a large, coastal fish of the monotypic 
family Rachycentridae, has a cosmopolitan distribution in tropical to 
warm temperate seas, except for the eastern Pacific Ocean (Briggs 
1960, Shaffer and Nakamura 1989). Cobia occur during summer in 
the United States coastal waters of the northern Gulf of Mexico and 
along the Eastern Seaboard from the Florida Keys north to Cape Cod 
(McClane 1965), although they are uncommon north of Chesapeake 
Bay (personal observations). Cobia migrate north along the Atlantic 
coast from northern Florida to the Carolinas, and then into Chesapeake 
Bay (McClane 1965, Shaffer and Nakamura 1989) during spring and 
summer. By late spring and early summer cobia enter polyhaline to 
mesohaline areas of major coastal bays, sounds and river systems in 
the Carolinas and Virginia (Musick 1972, Moore et al. 1980, Schwartz 
et al. 1981). Lone fish or “pods” of several cobia often hover in 
the shadow of near-surface objects, such as buoys, boats, sharks, and 
Brimleyana 23:1-23, December 1995 
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