Variation within the mitochondrial genome of the bull shark, Carcharhinus leucas

As apex predators, bull sharks (Carcharhinus leucas) serve a vital role in structuring ecosystems, necessitating their conservation for ecosystem based fisheries management.  Protecting nursery grounds for these predators is essential to their conservation, but requires delineation of nursery habitat.  The Texas coast has numerous areas with the potential for nursery habitat.  Understanding stock structure among these sites will aid managers in applying proper management.  We are examining the mitochondrial genome (mtDNA) of the bull shark for variation between loci commonly used in genetic studies.  The purpose of this study is to survey potential markers for population genetic structure analysis.  We will amplify and sequence three loci from seven western Gulf of Mexico sharks to determine the amount of variation present within each locus.  We selected the control region, NADH dehydrogenase subunit 4 (ND4), & cytochrome oxidase subunit I (COI) for comparison to determine which marker will provide the greatest amount of variation.  Variation will be compared using haplotype and nucleotide diversity estimations for each locus.  Haplotype networks will be constructed for each locus to determine the number and relationship of haplotypes.  Results will be completed in late summer to early fall 2011.  This study will inform future population structure studies for proper marker selection.  Ultimately, these future studies will help delineate bull shark nursery grounds along the Texas coast, providing managers with a valuable tool in shark conservation.