Dolphins in the Potomac

Dolphins swimming in the Potomac. All the photographs in this story were taken under NMFS Permit No. 19403 for the Potomac-Chesapeake Dolphin Project. The photograph above is by Megan Wallen (G’17), while the other photos of dolphins were taken by graduate student Ann-Marie Jacoby (C’13). Caitlin Karniski (C’11, G’19) took the photo of Janet Mann on the boat.

Graduate students working with Georgetown biologist and dolhpin expert Janet Mann have uncovered the first evidence that bottlenose dolphins are not only swimming, but breeding in the Potoamc river. This discovery comes as part of the Potomac-Chesapeake Dolphin Project, which began under the professor’s auspices five years ago as the first-ever study of the fascinating cephalopods in the river. 

Professor Mann’s research marks only the second documented birth of bottlenose dolphins. “I have spent 32 years studying wild bottlenose dolphins – logging tens of thousands of hours observing them, particularly mothers and calves,” Mann says. “Yet I have never seen a birth or even evidence of a recent birth. This recent sighting is really exciting.” Two graduate students – Ann-Marie Jacoby (C’13) and Melissa Collier (G’23) – were following a group of about 50 dolphins in the Potomac River near Lewisetta, Virginia, when Jacoby noticed a cloud of blood and shortly afterward a small calf with a “slightly bent and wobbly fin” surfaced and then swam alongside its mother. Though they straighten in a few hours, immediately after birth, calves’ fins are bent to one side.

The team named the mother dolphin the students observed after the late Patsy Mink, a former member of Congress representing Hawaii who co-authored the Title IX Amendment of the Higher Education Act. The calf was named after Mink’s daughter, Gwendolyn, a former academic-turned-independent-scholar who writes about law, politics and gender and American society.

The PCDP has a tradition of naming dolphins, who have been named everything from Ruth Bader Ginsburg to Ronald Reagan, after significant U.S. leaders.

The dolphins of the Potomac, so far numbering around 1,000, have been found as far up the river as the Rt. 301 bridge, only 70 miles from DC.