Wilson and Nieland: Reproductive biology of Sciaenops ocellatus 



847 



3 4 5 6 7 8 9 10 11 12 13 14 



GFBW (kg) 



3 4 5 6 7 8 9 10 11 12 13 14 



BW (kg) 



2 4 6 8 10 12 1416182022242628303234 



Age (years) 



Sept 17-18 + Sept 26-27 x Oct 4-8 



Figure 3 



Regressions of eviscerated body weight (BW), fork length (FL), gonad-free body weight (GFBW), and 

 age versus estimated batch fecundity for red drum from the northern Gulf of Mexico. Squares denote 

 specimens captured on 17 September 1986 and 18 September 1991, pluses on 26 September 1988 and 

 27 September 1987, and crosses on 4 October 1989 and 8 October 1986. n=total sample size. 



and further validates the use of a 1:1 ratio by Comyns 

 et al. ( 1991) in their estimation of red drum spawner 

 biomass in the north-central Gulf of Mexico. 



For immature red drum, males significantly out- 

 numbered females across all source and gear catego- 

 ries except among the few specimens randomly en- 

 countered at sportfishing tournaments. This numeri- 

 cal dominance of immature male red drum in off- 

 shore waters may indicate a predisposition for emi- 

 gration from estuarine habitats at younger age than 

 females which is reflected in the somewhat lesser 

 age and size at maturity seen in males. 



Previous accounts of red drum seasonality in the 

 northern Gulf of Mexico have relied on inferences 

 drawn from postspawning capture of larvae and ju- 

 veniles and, to a lesser extent, from visual assess- 

 ment of ovaries and testes. The red drum spawning 



season has been variously estimated with these 

 methodologies as September to December (Boothby 

 and Avault, 1971), August to November (Sabins, 

 1973), and from early September to early October 

 (Comyns et al., 1991). However, our delineation of a 

 mid-August to early October red drum spawning sea- 

 son is in accord with other studies that used histo- 

 logical techniques. Within our study area, analyses 

 of red drum oocyte maturation by Overstreet 1 in 

 Mississippi and by Fitzhugh et al. (1988) in Louisi- 

 ana both demonstrated that red drum spawning is 

 initiated in August and continues into October. 

 Murphy and Taylor ( 1990) found spawning red drum 

 from August to mid-November 1981 and from Au- 

 gust to mid-October 1982 in the Tampa Bay, Florida 

 area. The concordance among these estimates, drawn 

 objectively and directly from histological data, dem- 



