On her first day at the cottage on the lower Potomac that her husband bought her in an effort to get her away from her work in Australia, Professor Janet Mann stepped outside and said, “Look, there are dolphins!”
Janet Mann, a Georgetown professor of biology and psychology, spoke at Georgetown University on March 30 to discuss her 35 years of research on the social networks of bottlenose dolphins in Shark Bay, Australia, and her studies of wild bottlenose dolphins in the Potomac River and Chesapeake Bay. She is the first researcher to investigate dolphins in this area.
“Nobody was studying dolphin behavior in the field,” Mann said at the event. “I saw the potential where we could really study the individual lives of dolphins in-depth.”
Mann’s long-term study, “The Shark Bay Dolphin Research Project,” tracks over 1,800 dolphins throughout their lives and focuses on different aspects of delphinid biology and behavior. Mann’s guiding research question focuses on the large brain size, long life spans and social structures of these animals.
Meredith MacQueeney, a Ph.D. student in Mann’s lab, is specifically interested in researching with Mann the role of mothers in maintaining traditions and culture in dolphin societies.
“My research focuses on female reproductive behavior and determining if mothers actively teach their calves, as opposed to a more passive social learning mechanism like observation,” Macqueeney told The Hoya.
Mann’s newest study, the Potomac-Chesapeake Dolphin Project, began in 2015 with the mission of better understanding and protecting the area’s bottlenose dolphins. This project is the first attempt to study these dolphins — and the first time much of the general population has learned of the dolphins’ existence.
“The dolphins have been here. But there have been ups and downs,” Mann told The Hoya. “They were spotted in the 1800s all the way up to Alexandria and Georgetown and farther down near Quantico they were seen pretty regularly.”
Part of Mann’s research involves investigating fluctuations in dolphin populations along with the overall abundance, inner-population interactions and major risks to the group, such as fishing nets, water pollution and recent morbillivirus outbreaks. In the summer of 2013, a morbillivirus epidemic — a measles-like disease that causes skin lesions, pneumonia, brain diseases and other infections in marine mammals — depleted the coastal stocks of Atlantic bottlenose dolphins by approximately 40%.
Understanding how a virus spreads requires understanding the social structures of these dolphins. To do this, Mann and her collaborators use a variety of quantitative survey methods: fin identification; line-transect surveys that measure population abundance by having a boat travel along carefully designed lines while researchers record the distance from the line to every observed dolphin; and focal follows, where they follow an individual animal for several hours to track its behavior. These tools help Mann and other researchers understand the complex social lives of dolphins.
“Dolphin society is a fission-fusion society, meaning that individuals join and leave each other on a fluid basis. Those dynamics are extremely important because those animals are constantly making decisions about who to join with and for how long,” Mann said at the event.
Mann also said that most people in Washington, D.C. know nothing about these dolphins.
“Despite the dolphins having a major impact on the ecosystem here, as top predators, their existence isn’t even acknowledged by the NOAA [National Oceanic and Atmospheric Administration],” Mann said.
Mann hopes to gain a better understanding of how climate change and human factors are affecting the dolphins of the Chesapeake.
“Everything flows down river, the pollution of the Potomac impacts fish they eat and then that affects the dolphins themselves,” Mann said.
Mann’s work will inform priorities for conservation by emphasizing the importance of cultural ecological knowledge for dolphins. Mann said her main goal is to raise awareness about the uniquely complex, and almost human-like, social lives of dolphins.
“Dolphins are the other mind in the waters. We often only get a ‘Sea World’ view of these animals and I’d like to change that,” said Mann.