Madelyn In TCI: Black Spot Parasites

December 9, 2019

Time to talk about my research project here! There were many options of directed research, and I requested the one with my favorite professor here, even though it didn’t have a SCUBA component, only snorkel. Our project is analyzing how the presence and severity of a certain parasite that causes black spots on the body of its host might affect the Ocean Surgeonfish.

Field Work

The Ocean Surgeonfish eats a lot of algae on the coral reefs, which keeps the ecosystem healthy and allows the coral to grow further. But this parasite is one of those creepy ones that changes the behavior of its host. It basically hijacks the brain of the fish and makes it act very different. Our research is observing the Surgeonfish behavior and trying to determine a trend in the behavior changes of infected fish. We hypothesize that this parasite is causing the fish to behave more erratically and suppressing its anti-predator instincts, which would increase the likelihood of the fish getting eaten by an osprey, which is the next host of the parasite’s life cycle.

So, what does our actual field work look like? We go out every afternoon snorkeling for two hours and split up into buddy pairs. One of us videos the fish, while the other one records what the fish is doing exactly every 30 seconds when our timer goes off, and also records the number of bites every 30 seconds. We follow each fish for 10 minutes and record the number of black spots it has.

Recording Data

I really enjoy this type of field work because it forces me to focus on things that I typically wouldn’t notice. We are now well-acquainted with the typical behavior of the fish and notice when they do strange things. Then it’s easy to notice when the highly infected fish act strangely. We joke that they appear to be drunk, swimming erratically and running into rocks. We snorkel for about two hours each day collecting data, and usually by the end of it we’re all freezing cold and our hands are too numb to keep writing.

One day, after collecting behavioral data on many fish, we began to swim back to the boat. I dived down to swim along the sea grass upside down, looking up at the water surface. The change of perspective from doing this is always interesting- gazing at the waves distorting the sun rays that manage to filter through, I feel more as if I belong in this underwater reality. As I swam in this strange manner, I tilted my head back just a bit farther  to see where I was going, and realized that an eagle ray and I were swimming right towards each other!

A cute squid

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