SAVANNAH, Ga. (AP) — Officials say 15 pilot whales are dead after beaching themselves on a barrier island in the second mass stranding off the coast of Georgia since July.

Georgia Department of Natural Resources biologist Clay George said Thursday that scientists are performing necropsies on the dead whales found on St. Catherines Island. He says it's "too early to say" why they may have come ashore.

George said volunteers checking sea turtle nests first discovered several beached whales Wednesday. More were found nearby.

In July, three pilot whales died after at least 47 swam perilously close to shore on St. Simons Island, where beach goers scrambled to push them back toward the open ocean.

The American Cetacean Society says pilot whales are often involved in mass strandings partly due to their social nature.