Seyoum et al : Genetic population structure in Saaenops ocellatus 



137 



haplotypes at those locations. This approach may be 

 particularly important in studies of pelagic marine 

 species because, like red drum, genetic divergence 

 separating populations is often buried within a high 

 background of overall genetic diversity. 



Finally, Moritz (1994) described the potential of 

 using mtDNA as a marker for evaluating the suc- 

 cess of stock enhancement programs. For this appli- 

 cation, the mtDNA haplotypes borne by hatchery 

 fish should be sufficiently rare in wild populations. 

 The portion of control region we examined provides 

 an excellent source of naturally occurring genetic 

 markers. Because the percentage of wild red drum 

 individuals with different haplotypes in any given 

 sample averaged 87% and ranged up to 1001, a 

 genetic monitoring program using this mtDNA frag- 

 ment to track haplotypes borne by hatchery-released 

 red drum after release should allow for assessment 

 of the survival and reproductive output of these fish 

 in the natural environment. In addition, nucleotide 

 substitutions in this portion of the control region 

 could be used to estimate the contribution of each 

 female parent to the broods. This information will 

 be important in the evaluation of breeding protocols 

 designed to optimize levels of genetic variability in 

 hatchery broods, in the assessment of genetic risk 

 posed to wild red drum populations by hatchery stock- 

 ing programs (e.g. Tringali and Bert, 1998), and in 

 the evaluation of stock supplementation programs. 



Acknowledgments 



We thank M. Murphy and R. Taylor for valuable dis- 

 cussions regarding red drum life history, R. Muller 

 for advice on statistical analyses, and L. Barbieri 

 for providing information on biotelemetry studies of 

 red drum in Georgia. We also thank C. Crawford 

 for technical assistance and R. Crabtree, B. Falls, 

 A. McMillen-Jackson, S. Lotz, A. Redford, R. Ruiz- 

 Carus, and T. Thompson for assistance with field col- 

 lections. We thank the editorial staff of the Florida 

 Marine Research Institute, J. Gold, D. O'Foighil, and 

 D. Winkelman for valuable comments that improved 

 the manuscript. Financial support was provided by 

 the State of Florida and the U.S. Fish and Wildlife 

 Service, Department of the Interior, Federal Aid for 

 Sportfish Restoration Project Grant F-69 to TMB. 



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