HCNSO Student Theses and Dissertations
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Defense Date
1-2014
Document Type
Dissertation - NSU Access Only
Degree Name
Ph.D. Oceanography/Marine Biology
Department
Oceanographic Center
First Advisor
Mahmood Shivji
Second Advisor
Kevin A. Feldheim
Third Advisor
Jose V. Lopez
Fourth Advisor
Samuel J. Purkis
Abstract
Discerning the extent and patterns of genetic connectivity and understanding population demographic processes is essential for framing proper management and conservation measures for species of concern. Although genetic connectivity may be influenced by numerous biotic and abiotic factors, habitat utilization and dispersal potential are often key factors driving connectivity, especially in marine fishes. While dispersal potential is of key importance with respect to shaping connectivity, other extrinsic (e.g., oceanographic processes) and intrinsic (e.g., reproductive behavior) factors may also influence connectivity; however, the relative influence of such factors is immensely variable across species and life-stages. This dissertation explores genetic connectivity and demographic history in marine fishes with diverse dispersal potentials to determine which processes, in addition to the known dispersal potential of the species, may be shaping connectivity. Genetic connectivity and demographic history is assessed for four marine fishes: two shark species with juxtaposing dispersal potentials, the highly migratory tiger shark (Galeocerdo cuvier) and the reef associated Caribbean reef shark (Carcharhinus perezi), which possess high and low dispersal potentials, respectively, and two teleost species, the pelagic roundscale spearfish (Tetrapturus georgii) and the Nassau grouper (Epinephelus striatus), which possess high and low adult dispersal potentials, respectively. This work demonstrates that dispersal potential does, in fact, play a key role in delineating genetic structure for these species; however, other factors, such as contemporary oceanographic currents (e.g., upwelling and temperature), habitat availability (e.g., coral cover), and historical events, such as cyclical glacial cycles, also influence genetic connectivity across variable spatial scales, thereby creating complex patterns of genetic population structure, requiring composite management strategies to ensure the persistence of these species.
NSUWorks Citation
Andrea M. Bernard. 2014. Population Connectivity in the Ocean: A Genetic View of Upper Trophic Level Fishes Displaying Contrasting Life Histories. Doctoral dissertation. Nova Southeastern University. Retrieved from NSUWorks, Oceanographic Center. (86)
https://nsuworks.nova.edu/occ_stuetd/86.