2008 PFIG Recipient Leigh Corbitt

Career Administrator

Leigh Corbitt 
College of Arts & Sciences
2009 Graduation Year

Internship: Seattle Aquarium in Seattle, WA.

Notes on the first week

After getting off to a slightly chaotic start resulting from schedule conflicts and the director of interns being out of town, I officially began my internship this Monday. It is typical for most of the Seattle Aquarium's interns to choose a department (Puget Sound Wildlife, Pacific Coral Reefs and Exotics, or Marine Mammals) to focus specifically on, based on their goals. However, after discussing my background and personal interests with the coordinator, I was able to negotiate a schedule that will allow me to spend two days a week with the sea otters in the Marine Mammals program, one day with the Pacific Coral Reefs and Exotics team, and one day working in the laboratory doing research on deep-sea sixgill sharks.

My first two days were spent with the directors of the Puget Sound and PCR (Pacific Coral Reefs) programs. A lot of time was given to understanding the organisms we're working with. Learning things like optimal water temperature, salinity, and light requirements are crucial for providing a sustainable habitat to these organisms and a majority of my morning duties include analyzing and adjusting their specific habitat settings. Throughout the week, my supervisors also provided me with literature about the life forms and the ecology systems, which was actually extremely interesting and I found was a great way for me to learn and then actually see these organisms in their recreated habitats. My supervisors know how interested in conservation I am, and so they give me lots of interesting things to read about conservation biology as well. Another intern duty that I mastered this week was food preparation and presentation (where we feed the animals for aquarium visitors to watch) for both the marine mammals and PCR. I have a lot of fun watching the fish dart around to snatch up the food, with the exception of one very sassy puffer fish who likes to hang out at the surface of the tank and spit water at me when I lean into the tank. But my absolute favorite thing from this week was watching the birth of baby pot belly sea horses. They were almost microscopic the first time I went through and scooped them all up for counting, but they are getting bigger and bigger by the day.

I haven't spent very much time in the labs, but I have met with a few of the researchers who head up the projects I am most interested in, and I am really excited about getting to work outside the exhibits and broaden my experience at the aquarium. I am also hoping to make a little more progress with the sea otters in the next few weeks, maybe eventually working up to running one of the information sessions on sea otters that are offered on the aquarium tour. Overall, I think by making aquarium visits entertaining and fun, we can indirectly inspire visitors to get more involved in marine conservation, which is the inspiration behind my internship at the Seattle Aquarium.


A few more weeks into my internship, things have really picked up and I feel like I am really getting into the research and education that I set out for. Now mid-way through the summer I am continuing to help out the fish, invertebrates, and mammals teams but have also begun to spend a significant amount of time in the lab. After my first week I met with Shawn Larson, who is the curator of conservation research at the aquarium. I first learned about Shawn and the work she does with sea otters when I was doing some research for an ecology paper last semester. My job in her lab is to analyze both ancient (pre-1800, extracted from excavated sea otter bones) and modern day sea otter DNA to look for differences among the three major populations of sea otters (California, Oregon/Washington, and Alaska). Our goal is to show that the three existing populations are different enough in their genetics that mixing individuals from each of the populations would create an abundance of genetic diversity, and as I've learned from the many conservation biology classes I've taken at UVA, genetic diversity is the key to the conservation and recovery of a species.

Following the fur trade that led to a near extinction, the three sea otter populations in existence today are all descendants from just a few individuals. As a result, the populations show the effects of inbreeding and are extremely low in their genetic diversity. This is a major problem for the population when confronting new and stressful situations, including everything from new diseases to change in water temperatures. Basically if one otter of a population cannot survive a change in environment, none of them will, and the extinction of the species will take place.

My contributions to the project include organizing the DNA samples, which are taken from ancient sea otters bones and living fecal matter, and performing PCR (Polymerase Chain Reaction) using a variety of primers, and then looking for similarities between the samples with a genetic analyzer. This week I am finishing up some tests and working on an updated spreadsheet that will combine the data I have collected as well as all of Shawn's previous outcomes. With the results of our DNA studies, we hope to provide the genetic evidence to back up our conservation strategy.

In addition, this week the aquarium conducted a six-gill shark research experiment that I was able to observe and assist with. The Puget Sound is filled with six-gill sharks, which average about twelve feet in length, but almost nothing is known about them due to the little research that has been done. This week was spent setting up a research station underneath the pier the aquarium is built on and building an underwater diving cage for the biologists to wait in while the sharks are lured in with bait. The divers worked in two hour shifts, hoping to obtain a skin sample from the sharks in order for a biopsy to be done in the lab. National Geographic was here all week and I was actually filmed several times while working in the lab for their documentary!

I am still absolutely in love with my internship and continue to learn more and more about the plants and animals of the Pacific Northwest and the conservation efforts to save them everyday.

Final Reflections

In the final weeks of my internship I was finally able to organize all of the results from my genetic analyses for comparisons with data from other labs along different locations in the sea otters' home range. It took almost an entire week just to format all of the information so that we could submit it to an online statistical program. The spreadsheet I created primarily organized our samples by location. Most of the samples we work with are from the Washington sea otters at our own aquarium, but we also receive many samples from other locations including Cal Poly, Oregon, Alaska, Japan, and Russia, which constitute the major sub-populations we seek to compare.

The data given to us by the genetic analyzer in the lab show the microsatellites (alleles or variations) present in that sample. A reading of just one value indicates only one version of a gene, whereas two values would represent a heterozygous individual who inherited one variation of a gene from its mother and a different one from its father. The gene in question for this study is a silent gene, so it does not actually represent any identifiable trait, therefore, mutations and variations within it are much more common because they are not corrected like a mutation that would result in a lethality or mis-function.

We compare samples within a population to measure the genetic diversity or in this case, the lack of diversity, which is a result of inbreeding due to small population sizes. In nearly all of our sub-populations inbreeding seemed to play a major role, with very few otters showing heterozygosity (meaning both parents had similar DNA) for the gene in question.

Additionally, we found that among populations, Russia and Japan are much more closely related than either population is to California or Oregon . Samples in Russia and Japan contain similar alleles and show their alleles in similar distributions compared to samples from California or Oregon which show a much lower proportion of individuals containing that allele at all. This is very logical and can be reinforced by noting the geographic locations of the populations.

Although Dr. Larson will go into more depth in her paper about the conservation significance of these results, it is very obvious that although some populations are mixing, there is a serious inbreeding problem taking place, especially among southern sea otter populations. Therefore, these results will provide Dr. Larson and the other conservation biologists involved in the project significant data to reinforce their proposal to carry out our sea otter transplantation program.

Throughout this last part of my internship, in addition to all of my work in the lab, I continued to help out with the training, feeding, and enrichment of the marine mammals. Getting to personally work with the sea otters everyday was such a rewarding experience, and really reinforced my passion about their conservation.

In the end, I couldn't have asked for a more rewarding internship. Not only was I in paradise every single day when working with the aquarium animals, I also learned so much more than I could have in any classroom at school. I come away from this internship knowing that I made significant contributions to sea otter conservation efforts, which has only reinforced my desire to continue in this line of work after completing my degree.