Oceans4Generations
Current Dissertation Research
My first field season of dissertation research
After a successful field day with a couple of my undergraduate student volunteers
Research Background
The Pensacola Bay system, in the Florida panhandle, has a history of anthropogenic disturbances. Toxins were entering the system as early as the 1800s in association with a prominent logging industry. Since then, the ecosystem has been exposed to a major chemical spill, several red tide events (producing a biotoxin), increasing pressures associated with coastal development, and most recently, the Deepwater Horizon oil spill. Unfortunately, very little is known about the size or population structure of bottlenose dolphin populations in the Northern Gulf of Mexico such that our ability to evaluate threats is limited. Vessel-based surveys from an ongoing project in neighboring Choctawhatchee Bay (to the east) were expanded in 2010 to explore lower Pensacola Bay. The initial results provided evidence for a substantial bottlenose dolphin community for which no previous baseline population information existed. My PhD research is expanding on this initial work to: (1) quantify current population parameters (e.g., seasonal abundance, survival, reproductive rates and reproductive success) providing the first comprehensive baeline assessment of populations dynamics for the Pensacola Bay system; (2) to explore population structure and connectivity of dolphins between inshore, coastal and neighboring systems. Data from this project will also be used to examine distribution and site fidelity patterns and to develop a sighting history catalog to track individuals over time.
Current Research: Project 1
For the past 2 years, I have been surveying the inshore waters of the Pensacola Bay system, taking photos of individual dolphins that can be used to track them over time (called photo-ID). The survey technique is called mark-recapture whereby we ‘mark’ individuals by taking photographs of the natural dorsal fin markings and ‘recapture’ them over time. The proportion of ‘marked’ animals that are re-captured is used to estimate the total population.
This data will also be used to determine whether there is a local resident population that lives here all year.
The Pensacola Bay study area. The red lines are tracklines that are followed to survey the area.
The Pensacola Bay system is likely an important habitat for more than one population that may utilize resources that occur here. There is often overlap between animals that live inshore all year (residents), those that visit seasonally (seasonal residents), or those that simply pass through and may not be seen again (transients).
To date, we have surveyed across 8 seasons (2013: summer, fall, winter; 2014: early spring, late spring, summer, fall; 2015: spring). In order to start anlayses we have to process all the images taken over this time period and match them to a catalog of the individuals that have been seen in this area. Once this is complete I can start to run population abundance analyses that will be used to determine the number of dolphins here and how that varies seasonally as animals move in and out of the system. I hope to have some initial analyses completed this fall (2015).
Current Research: Project 2
Bottlenose dolphins in bays, sounds, and estuaries are known to establish long-term, resident populations, and generally remain in a discrete geographic area over time. Such small groups, compared with large coastal and offshore populations, may be particularly vulnerable to pulse events that lead to population declines. In order for a population to be viable over the long term, genetic connectivity to other populations is important. Without it, small inshore populations are susceptible to inbreeding and other consequences that could threaten the population. The second part of my research is to evaluate the level of connectivity between inshore and coastal population in the Florida Panhandle. This project will utilize genetic markers to determine genetic diversity, population structure, migration rates between populations, and evidence of sex-biased dispersal (i.e., generally speaking, where one sex tends to disperse from a population more commonly than the other).
I started a pilot project this summer (2015) to start collecting samples for this project. We've collected 23 samples so far towards a total of at least 40 needed for the inshore population. We will also sample coastal dolphins and dolphins in Choctawhatchee Bay.
A zebrafish moving through an "Emergence Task" where we measure the time it takes for individuals to move into a novel environment.
Master's Research
I received my M.A. in Experimental Psychology at the University of Southern Mississippi. I became very interested in individual differences in animal behavior and how these differences may be related to personality traits. Variation in behavioral responses to stimuli have been shown to be consistent over time and across context. This suggests that instead of being highly plastic, many behavioral responses may be constrained by an individual’s propensity to react in a specific way, resulting in important fitness consequences (i.e., influencing an individual's ability to survive and sucessfully reproduce).
I began trying to explore these concepts in marine mammals, but that proved more challenging than anticipated. So, instead I landed in a Behavioral Neuroscience lab, working with Dr. David Echevarria, to explore the use of zebrafish (Danio rerio) as a model organism. My research provided a comprehensive baseline of behavioral responses to commonly-used behavioral tests used to examine personality traits. We exposed zebrafish to predators, novel environments, novel objects and in a stiuation that was expected to provoke an aggressive response. I determined that they do in fact vary widely in the level of response between individuals, and sure enough, this variation is consistent over time and across different contexts. Some previous work had suggested this was so, but I was able to expand on it and create a more comprehensive baseline of behavioral tests to more appropriately assess these behaviors and explore the motivational underpinnings of their responses.
My project was designed to further explore why the presence of personality traits might be meaningful in an ecological context by exploring how different personality types response to stress and interact in social groups. However, the project was very large and was cut so I could actually graduate in a reasonable time frame. My final thesis was titled: Individual differences in zebrafish (Danio rerio) behavior: Implications for personality.
I learned more from this experience than I could have imagined and explored new and exciting topics that I aim to continue to incorporate throughout my career. Additionally, because my background had been primarily in marine mammal field work, I was also able to conduct experiments on a lab setting for the first time which was an invaluable experience. I was also fortunate enough to have several publications through this experience, the last of which as submitted recently!