A bottlenose dolphin on the shore in Ocean City.
The two dolphins that washed ashore in Ocean City bring the total count from the mid-Atlantic region to 291. The historical average for the summer months is 26.
Jennifer Dittmar with the National Aquarium in Baltimore says a similar dolphin die-off happened 25 years ago, which cut the number of coastal migratory dolphins in half.
The presumed culprit in this die-off is the measles-like virus that caused the last one: the moribillvirus.
"If you think about the stock of dolphins that was there for the 1987 event, we are going to pretty much have a fairly new stock of animals that may or may not have resistance to certain bacterial and viral diseases that are in their natural environment," says Dittmar.
And as the remaining population continues their migration south to warmer waters, scientists say the trend is continuing, pointing to 33 reports on dead or distressed dolphins that have washed ashore in the Carolinas in the past few weeks alone.