Reflections from the field: Theresa Cantu, Marine Biomedicine and Environmental Sciences doctoral student - Kruger National Park, S. Africa

Center for Global Health
November 14, 2014
Theresa Cantu with an animal in South Africa

Loskop Dam, South Africa – Fish Fieldwork 7/26/14-8/1/14

This particular week was one of the most challenging experiences that I’ve had as a graduate student. It was both physically and mentally exhausting. In graduate school, you learn to critically think about problems and solve them using logical methods; I utilized this skill many times during dissections due to working in an unfamiliar environment. When we first began necropsies, we had a hard time deciding which fish to target – in this particular area all of our collaborators told us that catfish (the species which we’ve had samples for in the lab analysis) did not present with the disease at Loskop.

That myth was shattered with our first dissection. We opened a catfish with full-blown pansteatitis (an inflammatory disease of adipose tissue). This surprised our collaborators and gave us hope that we could find fish with the disease at Loskop. After much deliberation with our team, we decided to focus on Mozambique Tilapia given that it was an opportunity to get large sample sizes and have another species of fish for laboratory analysis.

We spent our first day figuring out specific field protocols (blood sampling, measurements, etc.). Days began at 6:00 am with the catch team going out to set gill nets, while the rest of us set up necropsy equipment. We finished necropsies each day at sunset, mainly due to the loss of visual light, and had very few breaks outside of a sandwich at lunch. Dr. Guillette was the main dissector; he would start dissecting the fish then hand off samples to me for specific tissue processing. I was responsible for making sure each sample was processed correctly and put in the proper fixative (liquid nitrogen, Neutral Buffered Formalin, RNAlater), and that each dissection was done in a timely manner.

Dr. Bowden worked on the blood measurements and additional sampling outside of the datasheet. We worked seamlessly as a team, and successfully necropsied 50 fish (42 Tilapia and eight catfish). Our collaborator from Limpopo University, Dr. Wilmein Powell, worked with us to get accurate parasite load and other tissues for analysis. This was an amazing opportunity to work with Dr. Powell, as she was very helpful in pointing out slight nuances of the disease that is otherwise unmentioned in literature. It was also very educational at dinnertime to talk with our collaborators about what has been done in pansteatitis research and formulate other hypotheses for probable causative agents of the disease.

By the end of the week, our team left with many more questions than answers – but with renewed energy to do more lab analysis and investigations to get an accurate handle of pansteatitis. This was especially given the fact that we witnessed, first hand, evidence that local people were eating diseased fish. Moreover, we successfully ‘proved’ ourselves to our international collaborators in the way that we genuinely wanted to work with them rather than come in, take over, and completely disregard local knowledge. I had an amazing experience working with our international collaborators, and the graduate students – it was a rare experience to share what graduate school is like in the US versus graduate school in other countries. The social aspect also gave me insight into what living in another country would be like post-graduate school.

Overall, the project went well – we came in with the goal of 30 fish with varying levels of the disease to figure out sampling protocols for future work and left with a large sample set of 50 fish to work on. It was a difficult project to both organize and complete, but with the help of an extraordinary team of scientists, we figured it out and successfully brought back all of our samples to the US for analysis.

Crocodile Fieldwork 8/15/14-9/3/14

Since I was generously granted the funds for airfare to South Africa from the MUSC Center for Global Health, I talked with my mentor and he graciously allowed me to also participate in the crocodile fieldwork given that it was only scheduled a week apart. This was a tremendously enlightening experience! For the past three years in the Guillette Lab, I’ve learned how to catch alligators safely and obtain several tissues/blood samples for health analysis and laboratory work. Fieldwork is a true passion of mine; this was an amazing opportunity to receive training on safely capturing larger crocodilians for health assessments in a unique environment.

For our first study site, we visited Flag Bushielo – an area south of Loskop Dam and within the Olifants river catchment. This was an interesting site to catch crocodiles – mainly because we caught animals from a boat and the water is full of thorny Acacia trees (ouch!). Our team comprised of Matthew Guillette (field biologist), Dr. Louis Guillette (project PI), Dr. Hannes Botha (co-PI), Russ Lowers (NASA scientist and field collaborator), and myself. Another one of our collaborators supplied us with the boat and was our main driver (Dr. Willem Smit from Limpopo University). Matthew and Russ are amazing field biologists, and we came away from the site with nine samples, including a large 4m (13.5 ft) crocodile.

At first, I was hesitant working with these very large animals, but once we worked up one I soon became confident but aware of any safety issues (namely very sharp, serrated teeth!). I had an absolute blast working with crocodiles – their speed is amazing! Furthermore, it was great to have traditional Braii (South African BBQ) every night after long days in the field. This social time was so much fun as the group had plenty of hilarious field stories to share.

For our next study site, we traveled about 4.5 hours to Kruger National Park and set up camp in the bush. As an avid fan of the great outdoors, camping in Kruger was the definite highlight of the trip. We camped in the middle of the Bush, without a car or person for miles! This was both exhilarating (seeing wildlife in camp) and terrifying (hearing lions roar in the mornings and realizing a very flimsy tent is your only protection!). We had game rangers (a hilarious one at that!), and several other collaborators work with us on this project. This helped tremendously as it was physically taxing. The first day was spent carrying several (hundred pounds-at least!) cages down a steep cliff face to set for crocodiles.

This was very tough work, but also satisfying in the end. After that, we did very few active catching hikes due to the rough terrain and a large hippopotamus population. We hiked one night (around 3 miles), and that was another highlight of the trip because it was absolutely stunning. Dodging hippos was not fun, but the feeling of both serenity and apprehension in the middle of a night hike at Kruger is remarkable. The team caught one animal that night but had a great time talking with the workers there and getting insight into the different projects going on at Kruger with regard to crocodiles and larger mammals. Overall, we successfully caught ten crocodiles at Kruger – including the biggest crocodile of the study, a 5-meter crocodile (or for us Americans, over 15 ft!)

It was also great working as a researcher at KNP rather than a tourist because we had access to the park after-hours. This gave us a great way to see some amazing wildlife because we would start the day very early (4:00 am) and drive out to different sites. Some of the wildlife we saw included an “Auntie” pack of wild dog pups (amazing!), mating lions, baby hyenas, rhinos, a maternity herd of elephants, and leopards. Kruger was absolutely incredible – as a biologist, it was a remarkable opportunity to work in an environment very few people are allowed access to.

Moreover, it was a great opportunity to learn from my mentor how to represent myself internationally and create future research collaborations. It was inspiring as a young scientist to witness collaborations among people from various cultures, and identify what each person brings to the team as a whole. This experience was very educational; I learned that everyone brings exceptional and interesting skill sets to the team. The job of a PI is to identify people that work well together as a team and fulfill the goals of the project. Further, as a budding wildlife photographer, this was an incredible learning experience in a setting so full of biodiversity! My mentor is an excellent wildlife photographer (along with half of our team), so it was spectacular to get advice from the pros. All the pictures of wildlife are my own, I hope you enjoy!

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