At the time of the Deepwater Horizon oil spill in 2010, very little was known about the inshore bottlenose dolphin (Tursiops truncatus) populations hit hardest by the spill. Without previous population demographic data impacts were challenging to assess. My dissertation was designed to build research capacity moving forward by helping to fill data gaps in the western Florida Panhandle. The first study presented here resulted in the first system-wide assessment of seasonal abundance, survival, and site fidelity patterns of bottlenose dolphins that inhabit the Pensacola Bay system. In contrast to a previous study that reported only 33 dolphins, results from mark-recapture analyses estimated abundance ranging from 220-310 individuals, which consisted of a high proportion (43%) of transients. The second study revealed fine-scale genetic population structure (detected using both microsatellite and mitochondrial DNA markers) among five inshore systems in the Florida Panhandle. Migration rates were variable among populations with higher gene flow moving from east to west than in the reverse direction, and into St. Andrews Bay than coming out of it. There was no evidence of sex-biased dispersal. Finally, a 100-year flood (20 inches over 30 hours) occurred unexpectedly in the middle of my field work, after which dolphins were seen with extensive skin lesions. The event resulted in a unique natural experiment from which to evaluate the potential impacts of sustained freshwater exposure on local dolphin population health. Despite the persistence of a near freshwater environment for several months, skin lesions were not widespread but extensive and persistent for only some individuals, the reasons of which remain unknown. This body of work offers an updated perspective on the ecological and evolutionary connectivity of inshore dolphin populations in the Florida Panhandle, information of which is crucial for understanding how to best manage populations and assess new potential threats moving forward.
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Doctor of Philosophy (Ph.D.)
College of Sciences
Conservation Biology; Integrative Biology
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
Toms, Christina, "Filling the Gaps: Common Bottlenose Dolphin (Tursiops truncatus) Population Dynamics, Structure, and Connectivity Within Florida Panhandle Bays, Sounds, and Estuaries" (2019). Electronic Theses and Dissertations, 2004-2019. 6883.