Seeking Ecological Clues in the Digested Meals of Porpoises

 

Noelle Schoettle ’13

This summer, scientists at the Virginia Aquarium shipped the stomachs of 38 harbour porpoises to Noelle Schoettle ’13 for her to dissect. Schoettle spent her days in the farmhouse of Bowdoin’s Coastal Studies Center, at the end of a peninsula and far from people’s noses, sifting through the remains of old porpoise meals.

“They kept me as far away from other people as possible, so the smell of the stomachs didn’t offend anyone,” Schoettle said. The stomachs were removed from the corpses of stranded porpoises found between 1998 and 2010.

Schoettle, however, got accustomed to the strong odor and she relished her scientific purgatory. “I absolutely love the research I’m doing and have had a fantastic summer experience,” she said.

The Virginia Aquarium and Marine Science Center is interested in learning more about the foraging ecology of harbour porpoises because the small marine mammals have not yet been well studied, Schoettle explained. “We’re trying to create a solid data base to look at trends,” she said.

Her research, funded by a student/faculty research grant, should establish more clearly what porpoises prefer to eat, and what they will eat if their favorite prey is not available due to overfishing. The porpoises’ East Coast habitat extends from New Brunswick to North Carolina. Being so small, and living in such cold waters, the porpoises must constantly feed or risk starvation.

Inside the porpoise stomachs, Schoettle found a variety of fish, including silver sake, Atlantic menhaden, Atlantic herring, anchovies and squid beaks. To identify the items, she looked for the bony inner ear structure of a fish, which is the last fish bone to degrade. She’ll back up her identifications by performing PCR and DNA barcoding to match her results to data from the Fish Barcode of Life project, a genetic database for all fish species.

Schoettle plans on using her summer research to pursue a yearlong honors project, comparing the porpoises’ stomach contents to fish stock trends over the past two decades. She’ll look at historical fishing data, such as the recently overfished Atlantic herring stocks, and check to see whether the population decline of herring impacted the diets of porpoises.

“I’m really interested in the conservation of species,” she said. “I would hope that this research could contribute to fisheries research and regulation. For instance, if a certain preferred prey item is missing from the harbour porpoise diet in certain years, this can shed light on how that prey item was fished (and perhaps overfished), and the effects these fishing efforts are having on the harbour porpoise population.”

Following the Path
Although she is just a college senior, Noelle Schoettle ’13 has already accumulated an impressive amount of veterinary experience. She currently is an intern/veterinary technician at Sunray Animal Clinic in Bath, Maine, and has been a veterinary assistant at the Kenyan Society for the Protection and Care of Animals, a wildlife veterinary intern at Kenya Wildlife Services, an intern at Peninsula Equine Medical Center, an intern at Palo Alto Animal Services, a head junior volunteer at Wildlife Rescue, a fellowship student at Earthwatch Institute, a riding coach and horse caretaker at BOK Therapeutic Riding Ranch, an intern at Adobe Animal Hospital and a summer student at Tufts Cummings School of Veterinary Medicine.
A Lifelong Dream of Becoming a Vet

Schoettle has photos of her at four wearing a stethoscope to examine a stuffed animal, while a long line of other stuffed animals wait their turn. The Palo Alto, Calif.-native plans on attending veterinary school after graduating next year, and has narrowed down the animal group she wants to study — if narrowing is the right word — to marine mammals and other wildlife, small domesticated mammals or food production animals.

When talking about her professional aspirations, Schoettle shifts from statements that illuminate her scientific curiosity to ones that reveal her compassion. Her interest in food-production animals, such as dairy cows, derives from her desire to help build a more humane food-production system in the United States. Her interest in pets relates to her interest in people. “One of the things that appealed to me about being a vet is you’re not only helping animals, but also the people who care about the animals. I love interacting with the clients,” she said.

And her love of marine biology was sparked by a class, Marine Conservation Ecology, taught by Assistant Professor of Biology Damon Gannon, Schoettle’s advisor and the director of the Bowdoin Scientific Station on Kent Island. “Hands down, it was my favorite class,” she said. “Most biology classes zoom in on tiny organisms and systems, which is important for building a foundation of knowledge, but it was exciting to be able to apply this knowledge to larger animals systems, and in particular marine mammals.”

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