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Fishery Bulletin 91(2). 1993 



(1962) and Pearson (1929) for black drum from Texas 

 waters. 



Multiple oocyte stages were present throughout the 

 1986-87 spawning season, including primary growth 

 (PG), cortical alveolar (CA), and vitellogenic (V) stages. 

 Primary-growth oocytes were present year-round and 

 are a gonadotropin-independent stage (Wallace & 

 Selman 1981, DeVlaming 1983). Oocyte recruitment 

 from this PG population and onset of seasonal oogen- 

 esis was signaled by the appearance of CA oocytes in 

 October. Vitellogenic oocytes were noted in November, 

 and both CA and V oocytes persisted until May, indi- 

 cating the potential for a protracted spawning season. 



Descriptions of the breeding season for black drum 

 are varied. Gonad development and possible spawning 

 have been reported during the summer (Pearson 1929, 

 Cornelius 1984 cited in Cody et al. 1985). Our June, 

 July, and October samples did not indicate that spawn- 

 ing was evident. By November, reproductive develop- 

 ment for two females (yolk coalescence and final oo- 

 cyte maturation in histological sections) indicated the 

 potential for spawning to occur. Capture of black drum 

 larvae from offshore Louisiana waters has been re- 

 ported as early as December (Ditty 1986). Pearson 

 (1929) reported the primary spawning season was Feb- 

 ruary to May. Cody et al. (1985) described seasonality 

 of gonad development of black drum in Texas and re- 

 ported gravid females during November-April, with 



spawning or spent stages predominant dur- 

 ing February-April. From Florida, Murphy 

 & Taylor (1989) and Peters & McMichael 

 (1990) also report the reproductive season 

 ranges from November to April with Feb- 

 ruary-March spawning peaks. 



All the changes noted with the onset, 

 peak, and decline of the spawning season 

 were reflected both in histological samples 

 of ovaries and in gonad weight changes 

 relative to body weight (GSI) for females. 

 Increase in proportion of vitellogenic oo- 

 cytes was associated with GSI increase in 

 November and December. Appearance of 

 hydrated oocytes and postovulatory follicles 

 in February and March coincided with high- 

 est values for GSI. Subsequent appearance 

 of atretic vitellogenic oocytes in April, and 

 increase in atresia in May and June, were 

 associated with declines in gonad weights 

 reflected by decreasing GSI. The GSI sea- 

 sonal pattern for males coincided with the 

 pattern for females, and suggests a 

 synchrony in development of reproductive 

 states for both sexes. However, mean GSI 

 values must be interpreted with caution. 

 For the same stage of oocyte development, a larger 

 individual may exhibit proportionally larger ovaries 

 and a greater GSI value than a smaller individual 

 (DeVlaming et al. 1982). We apply the GSI here only 

 as a relative measure of changes in reproductive con- 

 dition over the spawning season, and not as a specific 

 measure of reproductive readiness or histological stage. 

 Black drum spawn in inside (estuarine, bay) as well 

 as in outside (coastal waters seaward of inlets) waters. 

 Pearson (1929) indicated spawning took place in Gulf 

 waters off Texas, although Simmons & Breuer (1962) 

 presented evidence for spawning in estuaries. Osburn 

 & Matlock (1984) present evidence from tagging stud- 

 ies for a "quasi-permanent" movement of black drum 

 >4yr from bays to the Gulf, where they may act as 

 spawning stock. Jannke (1971) cited evidence of estua- 

 rine spawning in the Florida Everglades, but also in- 

 dicated that spawning occurred outside the estua- 

 rine portion of the park. Peters & McMichael (1990) 

 report that spawning in the Tampa Bay region was 

 likely to have occurred both inside and outside the 

 bay. We also noted spawning activity over a gradient 

 from offshore to inshore. Examination of black drum 

 in hydrated condition from trawl landings during Feb- 

 ruary and March indicated spawning was occurring in 

 coastal waters off Louisiana. During late March, how- 

 ever, females in hydrated condition were taken by haul- 

 seine from inshore estuarine waters east of the Mis- 



