UTM marine biologist scuba dives to seek answers for ocean conservation

This U of T Mississauga professor dives deep to uncover data on life under the sea, yielding research that’s critically important for marine conservation efforts.

Cassidy D’Aloia, an assistant professor of biology at UTM, studies the molecular ecology of coastal fishes and invertebrates and tries to understand the patterns, causes, and consequences of dispersal and gene flow in the ocean. Put simply, she tries to understand when ocean life — whether fish, molluscs, or echinoderms — reproduce, where do their offspring go? How do their larvae move around in the ocean currents?

“Do you eat fish? Do you want to keep eating fish? Then dispersal data is important if you want to predict how fish populations will fare for the future,” says D’Aloia, who joined UTM in 2022 after completing her postdoctoral work at U of T.

As part of her research, she runs the D’Aloia Lab at UTM, where she and a team of graduate students work at the intersection of marine ecology, evolution and conservation biology, asking many interdisciplinary questions with answers that have profound implications on the future of marine life and conservation efforts.

Scuba diving in the coral reefs

D’Aloia and her team often collect ocean life data through scuba diving, sometimes in the southern Caribbean Sea off the coast of Belize or Curaçao, and sometimes in the north Atlantic Ocean off the coast of eastern Canada. Because much of their field work focuses on organisms living in coral reefs, they see firsthand the effects of climate change on the health of coral reefs and the organisms dependent on them.

Just this summer, she was diving off the coast of Belize when she saw how damaged coral reefs had become.

“Corals are critical to marine biodiversity,” she says. “Rising ocean temperatures are a huge problem for coral reefs because of the impact. We study a lot of things that live on corals and this year the coral bleaching was bad.”

A fisherman in the area where she was working told her it was the worst bleaching he had seen in his life. Coral bleaching happens when the water becomes too warm and corals expel algae living in their tissues, causing them to turn completely white. While they’re not dead in these scenarios, it places corals under more stress, makes them vulnerable to disease and can impact other species dependent on them, including human communities that rely on the ocean for their livelihoods.

An average day on the field in Belize involves waking up at 6 a.m. to eat breakfast and get the scuba equipment ready before getting to the water by 8 a.m. From there, she and her team swim out to the coral reef and begin diving where they record data, map populations and collect tissue samples from tiny organisms for genetic analysis.

With a few breaks in between, the team makes deep dives three times a day before heading back to the field station by 4 p.m. to clean the gear, backup their data, make dinner and sleep. All to do it again the next day. The field work goes on six days a week for a month or two.

“Our field work is gruelling,” D’Aloia says. “But I just love it, being in the field is by far the best part of the job. It’s a very special feeling being underwater, like visiting another planet. It’s a real privilege to be able to do that.”

D'Aloia has worked in Belize for many years, building and strengthening relationships with local fishers, the University of Belize and other researchers. Her work has led to partnerships in several areas including Fisheries and Oceans Canada with whom she works to develop science-based management plans for Canada’s fish stocks.

D’Aloia’s current research in Belize is funded by the Belize Fund for a Sustainable Future and UTM, in collaboration with the University of Belize’s Environmental Research Institute.

Why it matters

To understand how larval development of marine life is connected to conservation efforts, D’Aloia explains the consequences of larvae travelling far from their place of birth on ocean currents.

“We’re interested in how organisms move in the very early part of their life cycle,” she says. “It sounds simple, but it’s a tricky problem in marine biology.”

Larval dispersal determines how populations change over time and how they evolve. Species studied include snails, gastropods, cod, American lobster, sea cucumbers, hogfish and conch fish.

“Fish and harvested invertebrates are one of the last wild animals we still harvest in their natural environment, so I think it lends itself well to the integration of science and policy and trying to work together to give the fundamental scientific data that can help us make sustainable choices,” D’Aloia says.

“If we want to make decisions on spatial conservation, then you need this data.”

D’Aloia grew up in New York state, away from the ocean, but she always loved science and biology. As a result of great teachers in high schools and encouraging professors in university, she sought to become a marine biologist and “fell in love with the ocean.”

Now an assistant professor overseeing a team of graduate students, she offers training and support for students to conduct research and build their careers as marine biologists. That includes learning how to scuba dive.

“Research that can support the conservation of those ecosystems is so important,” she says. “I think supporting students who are trying to pursue good research and want to make a difference in the world is a good thing.”