Two more dolphins were found dead off Beaufort County shores this weekend, bringing the total since March 17 to five.
One was discovered Saturday near Sea Pines on Hilton Head Island, and the other Sunday near The Sands beach in the town of Port Royal, according to Wayne McFee of the National Oceanic and Atmospheric Administration.
The dolphin discovered in Port Royal -- a 6-foot adult male -- was tied to the dock at The Sands until it could be retrieved Monday. Representatives of the S.C. Marine Mammal Stranding Network in Charleston came to recover both dolphins.
The cause of the dolphins' deaths was not immediately known.
Three previous dolphin deaths have been reported in recent weeks.
A bottlenose dolphin washed ashore March 17 on Hilton Head Island between Sea Pines and Marriott's Grande Ocean Resort. It died before marine biologists could reach it. That was an older male that had a heart condition and perhaps pneumonia.
The second was spotted March 20 in the May River in Bluffton. The third was discovered by kayakers March 22 in Fripp Inlet, but it washed out to sea before biologists could recover it, McFee said.
The two dolphins from this past weekend will be taken to the Marine Mammal Standing Network for testing. The other two carcasses were taken there as well, according to Jessica Conway, a technician for the network who retrieved the dolphins Monday.
Test results take a few weeks, McFee said. Only then can it be determined whether the deaths are related to a deadly outbreak of morbillivirus that has been affecting dolphin populations along the East Coast.
"These may be part of the event that has been going on for the last few months ... or it could be more virus infections," McFee said. "But we won't know until we get results back."
The deaths appear to only be among dolphins migrating along the coast, not the resident population of the Lowcountry estuaries, he said.
Anyone who finds a stranded dolphin should not attempt to push the animal back into the water but should call the Marine Mammal Stranding Network at 800-922-5431.
Follow reporter Erin Moody at twitter.com/IPBG_Erin.