FISHERY BULLETIN: VOL. 82, NO. 1 



were low (0-8.1%) (Table 1). Although sampling 

 effort in the Cape Fear area was half of that near Cape 

 Lookout from June through August, more female 

 banded drum were collected near Cape Fear; 

 however, the percent of females with large gonads 

 was much greater in the Cape Lookout area (Table 1 ) . 

 Cape Fear area sampling effort doubled over that 

 near Cape Lookout in September and yielded many 

 more female banded drum, but only 0.7'r were re- 

 productively active compared with 48.9% in the 

 Cape Lookout area (Table 1). Irregular sampling 

 from the Cape Hatteras area (Fig. 1) yielded matur- 

 ing or ripe L. fasciatus only during April when 82.4% 

 of the females collected had gonad indices between 

 1.7 and 6.1 (Table 1). Bottom water temperature in 

 this area was 17°C. 



Ovum diameter is often an indication of sexual 

 maturity (Higham and Nicholson 1964), and the 

 relationship between egg size (OD) and gonad index 

 (GI) for banded drum {n = 90) was 



OD - 0.34 + 0.1 1 (In GI), r = 0.77 



(Fig. 4). This relationship is an objective, quantita- 

 tive way to determine degree of maturity (Yuen 1955; 



Schaeferand Orange 1956) and was used to differen- 

 tiate maturing from immature female banded drum. 

 The point on the graph (Fig. 4) where gonad index 

 began to increase more rapidly than egg size was used 

 as the boundary between immature and maturing 

 gonads and occurred around a gonad index of 1.0 and 

 an ovum diameter of 0.35 mm. Mean ova diameters 

 peaked from July through September at 0.48 mm 

 (Table 2), which also coincided with the highest 

 gonad indices. 



Maturity 



Female banded drum reached sexual maturity be- 

 tween 120 and 130 mm SL (n = 112). All fish <120 

 mm SL were immature (GI <1.0) and 97% of those 

 >130 mm were mature, with 607t between 120 and 

 130 mm reaching maturity (Table 3). During the 

 spawning season, females between 120 and 130 mm 

 indicated increased gonad activity. Females smaller 

 than 120 mm displayed no seasonal gonad activity, 

 while only three fish >130 mm were not maturing 

 during the spawning season (Fig. 5). Only the larger 

 adults >150 mm matured and spawned early (April), 

 and generally a higher proportion of the older 



0.6 



5 



£ 

 E 



<x 



4 



•S 0.3 



< 



Q 



I 0.2 



> 



o 



o i 



••• • ••« 



OD = 0.34 + 0.11ILnGII 



r = 0.77 



n=90 



3 4 



GONAD INDEX 



FIGURE 4. — Relationship between famale gonad index and ova diameters of North 



Carolina Larimus fasciatus. 



230 



