16 
Joseph W. Smith 
Table 7. Cobia from North Carolina and adjacent waters, 1983-94, in various stages 
of sexual development by 5-cm-FL intervals. 
Midpoint 
5-cm-FL 
Males 
Females 
Immature 
Developing and Ripe 
Immature 
Developing 
Ripe 
< 50 
5 
0 
4 
0 
0 
55 
1 
0 
1 
0 
0 
60 
1 
3 
1 
0 
0 
65 
0 
6 
1 
0 
0 
70 
0 
5 
1 
2 
0 
75 
0 
22 
5 
0 
0 
80 
0 
23 
0 
6 
0 
85 
0 
25 
0 
11 
0 
90 
0 
11 
0 
19 
1 
95 
0 
17 
0 
8 
0 
100 
0 
7 
0 
9 
0 
105 
0 
0 
0 
11 
0 
110 
0 
1 
0 
9 
0 
115 
0 
0 
0 
5 
0 
120 
0 
6 
0 
125 
0 
8 
0 
130 
0 
2 
0 
135 
0 
2 
0 
140 
0 
1 
0 
Totals 
7 
120 
13 
99 
1 
many small basophilic oocytes with a few early vitellogenic oocytes 
(Fig. 5b), whereas the ovaries of late developing females had large 
(ca. 750 ;i m), yolk-filled oocyctes (Fig. 5c). Only one female had 
hydrated oocytes; it was uncertain if this fish was caught in estuarine 
or oceanic waters. A few females (collected in early June 1990) showed 
follicular atresia indicative of a recent spawn, yet also possessed numerous 
large oocytes, suggestive of an incipient spawn (Fig. 5d). 
Mean gsi’s for female cobia were high in May at 5.5 (SD = 
2.2, n - 8), peaked in June at 5.7 (SD = 2.1, n - 49), and declined 
slightly in July at 5.3 (SD = 2.2, n = 8). The largest ovaries excised 
weighed 2.49 kg (7 June) and were in a female weighing 25.4 kg. 
Peak spawning in June 1989 was confirmed by neuston net collections 
of cobia eggs from a channel in the lower Newport River estuary 
about 3 km from Beaufort Inlet (Fig. 1) (L. Settle, National Marine 
Fisheries Service, Beaufort, North Carolina, unpublished data). During 
10 sampling dates between 14 June and 18 August, peak cobia egg 
