Whale watchers have confirmed the first known collision between a right whale and a ship in six years.
The whale was first spotted off the Georgia coast in mid-January.
Aerial observers with the Eco Health Alliance later spotted the whale with propellor gashes on its back east of Charleston.
The group's Cynthia Taylor says, ship strikes are one of the primary non-natural causes of death for the endangered whale.
"It's very rare to know the type or size of ship or actually to have the ship report the incident," Taylor says.
The whale appeared to be behaving normally.
But Taylor notes, not many whales survive such wounds.
Scientists estimate, only about 450 right whales still exist.
They migrate to their calving grounds off the Georgia and Florida coasts during the winter.
Another non-natural cause of right whale deaths is entanglement from cast-away fishing gear.