Moon jellyfish can be recognized by their four horseshoe-shaped gonads and small tentacles. Photo: istock.

Covered in jellyfish slime, and couldn’t be happier

Jessica Schaub’s fascination with marine life started with The Little Mermaid and two small aquariums. Now, her research on jellyfish could inform global ocean ecosystem conservation.

UBC Science
Nov 5 · 5 min read

By Jessica Schaub, Master of Science in Oceanography student at the University of British Columbia, Pelagic Ecosystems Lab.

Imagine you’re standing on a boat in northern British Columbia, with cedars along the shoreline and an emerald green ocean beneath you. A humpback whale spouts in the distance. You look down into the water and see thousands of blue jellyfish, about the size of your hand, stretching as far as you can see.

This was my first encounter with a jellyfish smack (commonly jellyfish ‘blooms’, or large aggregations of jellyfish) near Calvert Island. I had been sent there as an undergraduate student for a drone mapping project that was targeting these smacks. We were interested in measuring jellyfish blooms using drones, as it hadn’t been done before. This would solve some of the issues in locating and measuring jellyfish that researchers usually face.

As the drone buzzed around us, we hauled nets of jellyfish into the boat for counting and measuring. The water was so thick with jellies that it took three of us to pull the nets into the boat. By the end of the day, I was slippery with jellyfish slime and couldn’t have been happier. I was excited, thinking about having so many jellies in one place and how that must be changing the biology, chemistry and physics of the water. This was, and is, what drives me.

Blooms of moon jellyfish, observed with a drone. Photo: Keith Holmes/Hakai Institute

Although I grew up in the prairies, I’ve always been drawn to the water, wearing out our Little Mermaid VHS. I had to be limited to two fish tanks when I was growing up, otherwise, I would have filled our house with fish. When I ate my breakfast in the morning, I pulled up a chair and sat in front of my tanks so I could watch the fish. It was an easy choice to pursue a degree in oceanography at UBC. I was broadly interested in marine animals when I applied, but a few months before I left, I watched a documentary about jellyfish and was hooked!

Two years after I moved to Vancouver, I began volunteering in the jellyfish hallway at the Vancouver Aquarium. This was my first time getting hands-on experience with jellyfish and I still volunteer. The more I learned about jellyfish, observed them and handled them, the more I liked them.

They are strange animals — simple yet complex, hearty yet delicate. I remember hearing about their resilience under poor environmental conditions, like low oxygen, so I was surprised that the first time I held one out of the water, my fingers poked right through it. It was surprisingly delicate for something that has been around for millions of years.

Even though jellyfish have been around for millions of years, they’re poorly studied. My work focuses on moon jellyfish, Aurelia spp., the dominant smack-forming species in British Columbia. Like many =related jellyfish, they have two morphs in their life cycle. Most people are familiar with one of the jellyfish’s morphs — the medusa. The medusa is the life stage of a jellyfish that is a floating blob with tentacles hanging down. But jellyfish have another morph as a small polyp that lives attached to a surface and resembles tiny sea anemones, with tentacles that point up. It seems that polyps preferentially settle on manmade structures and materials — like docks and plastics — which could be a reason that we are seeing more jellyfish in some areas with a large human presence. The polyp morph of a jellyfish’s life is very poorly understood and this is where a portion of my work focuses.

Jessica in the field. Photo: UBC.

In order to understand moon jellyfish, my master’s thesis is studying the diet of both medusae and polyps in BC. We are using a combination of molecular approaches, like genetics and stable isotopes, to learn about what a colony of polyps or a smack of moon jellyfish eats. Genetics allow us to identify their stomach contents when we collect them, while stable isotopes give us a time-integrated look at the nutrients that they are incorporating in their tissues as they grow. Isotopes also give us clues about what they are eating and where they derive their energy from over longer timescales, as some prey types have specific signatures that can be measured in the jellyfish.

Jellyfish blooms can sometimes extend for miles and miles. Photo: istock.

This is a small part of figuring out the bigger role of jellyfish in the ecosystem, especially here in BC. It’s likely that they occupy the same place in the food web as important species of fish — like salmon — and compete with them. Polyps also reproduce differently depending on the food they’re given, which might affect how jellyfish blooms change from year to year. With this research, we will better understand how they fit into the food web and how they impact our ecosystem. Moon jellyfish are found all over the world, so our results will be globally relevant.

So next time we stand among the cedars and whales and look down into a smack of jellyfish, we’ll be one step closer to knowing the secrets of these enigmatic creatures. Stay tuned!

Learn more about Jessica’s research.

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Stories from the Faculty of Science at the University of British Columbia | Edited by Silvia Moreno-Garcia, assistant editor Koby Michaels |


Focus: Stories from the Faculty of Science at the University of British Columbia

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