Abstract.— Patterns in oocyte de- 

 velopment, batch fecundity, and 

 spawning frequency were assessed 

 for black drum Pogonias cromis from 

 Louisiana. We identified histological 

 oocyte stages present throughout a 

 protracted breeding season in 1986- 

 87. We observed vitellogenesis be- 

 ginning in November, and first 

 postovulatory follicles were detected 

 in February. Atresia of yolked oo- 

 cytes was complete in May. We de- 

 tected recruitment of vitellogenic 

 eggs after the onset of spawning, 

 suggesting indeterminant total fe- 

 cundity. Mean batch fecundity for a 

 6.1kg female (mean size sampled 

 with hydrated oocytes) was calcu- 

 lated to be 1.6 million hydrated oo- 

 cytes. A field estimate of spawning 

 frequency was 0.311, indicating that 

 a female spawns on average once ev- 

 ery 3d during the breeding season. 

 Sex ratios were skewed with respect 

 to sampling gear during the breed- 

 ing season, suggesting segregation 

 of actively-spawning fish on the 

 spawning grounds. 



Ovarian development fecundity, 

 and spawning frequency of 

 black drum Pogonias cromis 

 in Louisiana 



Gary R. Fitzhugh 



Department of Zoology. Box 76 1 7. North Carolina State University 

 Raleigh. North Carolina 27695-76 1 7 



Bruce A. Thompson 



Coastal Fisheries Institute, Center for Coastal, Energy and Environmental Resources 

 Louisiana State University, Baton Rouge, Louisiana 70803-7503 



Theron G. Snider III 



Department of Veterinary Pathology, School of Veterinary Medicine 

 Louisiana State University, Baton Rouge. Louisiana 70803-8420 



Manuscript accepted 28 January 1993. 

 Fishery Bulletin. U.S. 91:244-253 ( 1993). 



The black drum Pogonias cromis 

 ranges from Argentina to the Bay of 

 Fundy (Sutter et al. 1986) and is the 

 largest sciaenid, up to 66 kg 

 (Hildebrand & Schroeder 1928). A 

 maximum age of 43 yr was recorded 

 for black drum in the northern Gulf 

 of Mexico (Beckman et al. 1990). 

 Fishing pressure on black drum was 

 historically very low, but has in- 

 creased with commercial landings in 

 the Gulf of Mexico rising from 1.9 

 million kg in 1982 to 4.8 million kg 

 in 1987 (NMFS Natl. Fish. Stat. Of- 

 fice, New Orleans LA 70130). 



Many temperate fishes are serial 

 spawners with variable production of 

 clutch sizes (Hunter & Goldberg 1980, 

 DeMartini & Fountain 1981, Conover 

 1985). In particular, large long-lived 

 species may exhibit high variability 

 in reproductive output (Ware 1982). 

 An important management objective 

 with long-lived species is to identify 

 changes in population egg production 

 associated with the harvest loss of 

 older age-classes. For black drum, the 

 potential for exploitation of older age- 

 classes is increased with development 

 of the commercial fishery (NMFS 

 1986). 



Despite the commercial value of 

 black drum, relatively little is known 



of many life-history aspects of this 

 species (Sutter et al. 1986). In the 

 northern Gulf of Mexico, the spawn- 

 ing season has been reported from 

 late-fall to spring, based upon egg 

 and larval distributions ( Jannke 1971, 

 Holt et al. 1985, Ditty 1986) and oc- 

 currence of gravid females (Cody et 

 al. 1985). Peters & McMichael (1990) 

 reported peak spawning in March 

 from Tampa Bay, Florida, based on 

 distribution of larvae and juveniles. 

 Murphy & Taylor (1989) computed 

 size-at-maturation to be 590 mm 

 and 650 mmFL for males and fe- 

 males, respectively, although there 

 have been accounts of small fe- 

 males (<350mmFL) with developing 

 ovaries (Simmons & Breuer 1962, 

 Pearson 1929). Spawning locations 

 have been reported to occur within 

 estuarine bays and in open coastal 

 waters (Pearson 1929, Simmons & 

 Breuer 1962, Jannke 1971, Peters & 

 McMichael 1990). There has been only 

 one estimate of fecundity determined 

 from a single female (Pearson 1929), 

 and no previous estimate of spawn- 

 ing frequency has been made from the 

 adult stock. 



Our objective is to provide baseline 

 reproductive information from 1986- 

 87 to be used in assessing popula- 



244 



