A shark washed up dead on a South Shore beach Thursday morning, while a great white shark was spotted 5 yards from the Cape Cod shoreline.

Shark researcher John Chisholm had received a report from fishermen about a thresher shark “acting odd” in very shallow water off Duxbury Beach Wednesday night.

“This morning it washed up dead,” Chisholm posted. “It was a 12′ mature male that was recovered for a necropsy. Michelle Passerotti (NOAA biologist) & crew will try to determine cause of death.”

Meanwhile on Thursday, the Atlantic White Shark Conservancy’s Sharktivity app had reports of great white sharks close to shore along Chatham.

“White shark spotted 5 yards off of Monomoy Island headed south,” one shark report reads.

There were other reports of white sharks 25 yards and 40 yards offshore.

Chatham’s Monomoy Island is typically a very busy shark area during the summer and fall, as the apex predators hunt for seals.