Three more dolphins wash up at the Jersey Shore Friday re-surfacing the burning question: What is killing these beloved sea mammals?

According to the Asbury Park Press, each dolphin was found beached miles apart in Seaside Heights, Longport, and Stone Harbor.

Photo Courtesy of Jersey Shore Hurricane News Facebook

The Marine Mammal Stranding Center in Brigantine was involved in recovering the dolphins, which brings the total of dead dolphins found at New Jersey's beaches to 49 since July 9.

RELATED: Bottlenose Dolphin Strandings Spike on East Coast

The federal government has been investigating the cause of dolphin deaths up and down the Eastern Seaboard this summer, exploring a number of possible causes such as disease, changes in the environment and human activities.

Since early July, at least 140 dolphins have been reported dead or dying along the coast from New York to Virginia.