where bottlenosed dolphins were spotted in 2018
Source: University of Maryland Center for Environmental Science, DolphinWatch
Bottlenose dolphins (Tursiops truncatus) swim in the Atlantic Ocean within three miles of the Virginia shoreline, within state-controlled waters as well as further offshore. The marine mammals also live in the Chesapeake Bay, and swim up the rivers. There was a dolphin sighting as far upstream as Washington, DC in the 1880's.
Within the Chesapeake Bay, there are different populations of dolphins. Some belong to the Northern Migratory Stock and others to the Southern Migratory Stock, which are separate populations as defined by the National Marine Fisheries Service (NMFS). Within Virginia waters there may be members of a third population, the South Carolina-Georgia Coastal Stock.1
The Potomac-Chesapeake Dolphin Project and the Potomac Conservancy have identified over 1,000 unique dolphins migrating through the bay and into the Potomac River during the summer. They swim upstream as far as the Harry Nice Memorial Bridge, where US 301 crosses the river.
Over 300 of the dolphins have been assigned names, while others are giving just identifying numbers. In 2019, the two organizations invited supporters to "flip out" and give names to two dolphins labeled D1 and D2.2
dolphins D1 and D2 were given names in 2019
Source: Potomac Conservancy, Name two Potomac River dolphins!