Wilson and Nieland: Reproductive biology of Sciaenops ocellatus 



849 



Prior to the confirmation of batch spawning in fe- 

 ral red drum by Fitzhugh et al. ( 1988), fecundity of 

 wild caught specimens had been variously estimated 

 as 0.5-3.5 million ova per season (Pearson, 1929; Holt 

 et al., 1981; Miles 5 ). Much greater potential fecun- 

 dities (up to 94.5 million), based on volumetric and 

 gravimetric estimates of oocytes available for spawn- 

 ing, were presented by Overstreet 1 . This potential 

 for an immense seasonal reproductive output in wild 

 red drum has been demonstrated in the laboratory 

 where specimens have been manipulated to produce 

 repeatedly a few hundred thousand to millions of ova 

 per spawning event (Arnold et al., 1977; Roberts et 

 al., 1978; Anonymous, 1979; Arnold, 1988). Other 

 than the batch fecundity estimates for feral red drum 

 presented by Fitzhugh et al. (1988) and those herein, 

 only one other estimate has appeared in the litera- 

 ture. Comyns et al. (1991), from our data for Sep- 

 tember of 1986, 1987, and 1988, used a mean batch 

 fecundity of 2.128 million ova in their computations 

 of red drum spawner biomass in the north-central 

 Gulf of Mexico. 



Our seasonal estimates of spawning frequency are 

 the first to be presented for red drum in the wild. 

 Those seasonal frequencies (3-5 d) calculated for 

 1986, 1987, and 1989 with the postovulatory method 

 and those (2-4 d) calculated for 1986-1991 with the 

 time-calibrated method are believed to be most rep- 

 resentative of the spawning population as similar 

 spawning frequencies have been observed in the labo- 

 ratory (Arnold et al., 1977; Arnold, 1988). However, 

 spawning frequency is likely not constant over the 

 course of the spawning season. Within-season spawn- 

 ing peaks coinciding with the new and full moon have 

 been postulated by Peters and McMichael ( 1987) and 

 Comyns et al. (1991) based on larval abundances. 

 The irregularity of our sampling precluded our in- 

 vestigation of this phenomenon. 



Given an 8—9 week spawning season, a mean batch 

 fecundity of 1.54 million ova, and a spawning fre- 

 quency of 2— A days, an average red drum female could 

 be expected to spawn some 20^10 million ova per 

 season. Among sciaenid species, this estimate of an- 

 nual fecundity is exceeded only by that of the black 

 drum, a species of similar size which has an annual 

 fecundity of 35-45 million ova (Nieland and Wilson, 

 1993). Females of both species are potentially long- 

 lived (30-35 yr) and, thus, might produce up to a 

 billion of ova during their lifetimes. 



Acknowledgments 



The authors gratefully acknowledge Daniel Beck- 

 man, Gary Fitzhugh, Brigitte Nieland, Robert 



Parker, Louise Stanley, Bruce Thompson, a host of 

 graduate students and student workers, and person- 

 nel of the National Marine Fisheries Service for their 

 assistance in field sampling. Phillip Horn, Ralph 

 Horn, Harlon Pearce, and numerous fishing tourna- 

 ment organizations generously allowed us access to 

 and use of their facilities. We especially thank Paul 

 Morse, Jim Reahard, Jimmy Reahard, and the crews 

 of the fishing vessels Captain Grumpy and Mistake 

 for their help and hospitality. Permits for possession 

 and transport of red drum, logistical and moral sup- 

 port were provided by the National Marine Fisher- 

 ies Service, Louisiana Department of Wildlife and 

 Fisheries, and Mississippi Bureau of Marine Re- 

 sources. Major sources of funding for this research 

 were the U.S. Department of Commerce Marine Fish- 

 eries Initiative (MARFIN) Program and the Louisi- 

 ana Sea Grant College Program, a part of the Na- 

 tional Sea Grant College Program administered by 

 the National Oceanic and Atmospheric Administra- 

 tion, U. S. Department of Commerce. The Louisiana 

 Sea Grant College Program is also supported by the 

 State of Louisiana. 



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