Biesiot et al.: Ovarian development in Rachycentron canadum 



695 



tember season. Their conclusion was based on the 

 observed nonsynchronous formation of oocytes in the 

 ovaries, considered to be strong evidence of multiple 

 spawning (Hunter et al., 1992). Nonsynchronous 

 development of oocytes was also observed in the 

 present study. Data from this study further suggest 

 that cobia resorb unspent stage-3 oocytes after ovu- 

 lation. This hypothesis is supported both by the bio- 

 chemical data and the histological evidence of re- 

 sidual lipid in stage-4 and stage- 1' ovaries. 



In summary, we have determined that lipid con- 

 centration, but not protein concentration, changes 

 during cobia ovarian development, presumably as 

 lipid yolk reserves are deposited in the oocytes. Car- 

 bohydrate and ash concentrations also varied dur- 

 ing development, but they were only minor compo- 

 nents of the system. Further research is needed on 

 newly fertilized cobia eggs and developing embryos 

 and larvae in order to answer questions about the 

 patterns and rates of energy reserve utilization dur- 

 ing embryogenesis and during larval development 

 before first feeding in this species. Because cobia eggs 

 and larvae are only rarely found in plankton collec- 

 tions in the Gulf of Mexico, we have initiated studies 

 on the spawning of ripe, field-caught cobia (Caylor 

 et al., in press). 



Acknowledgments 



This work was supported in part by the Mississippi- 

 Alabama Sea Grant Consortium (Grant No. 

 NA16RGO155-01, Project No. R/LR-26 awarded to 

 PMB and JSF) and by the U.S. Fish and Wildlife 

 Service, Sportfish Restoration, Atlanta, GA, through 

 the Mississippi Department of Wildlife, Fisheries and 

 Parks/Bureau of Marine Resources (Project #F-91 

 awarded to JSF). We thank Adam W. Hrincevich for 

 his help collecting samples and Joanne Lyczkowski- 

 Shultz and Robin M. Overstreet for reviewing an 

 earlier version of the manuscript. We also thank two 

 anonymous reviewers and the scientific editor for 

 their helpful comments. Bob Barber kindly provided 

 some of the cobia samples from Texas. 



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