The body of a man in a wetsuit was discovered in the water in the Rowley Shore Road area midday on Saturday.
He has been identified as Thomas Cooke, 57, of West Boylston.
"He was a diver and there is no foul play suspected," said Carrie Kimball, a spokeswoman from the Office of Essex District Attorney Jonathan Blodgett.
Cooke was discovered by Lanesville resident Kim Spaner who went down to the water around 11:59 a.m. and saw a fin that seemed to be attached to something more.
Grabbing her binoculars to get a closer look, Spaner saw that it was a body "that didn't look alive," she told a Times reporter Monday afternoon.
"We found him floating," she said, explaining that she had called her husband over at the time of the incident. "We don't know who he is or where he is from."
Cooke's body was recovered by the Gloucester Police Department in the water between Plum and Lanes coves, said police Chief Ed Conley in a press release.
The Coast Guard launched a boat from Station Gloucester and a helicopter from Air Station Cape Cod to search from the mouth of Annisquam River to Halibut Point in Rockport for any other divers.
"We searched until such time that we knew he had been 100% alone," Coast Guard Chief Warrant Officer John Roberts said.
Taylor Ann Bradford can be reached at 978-675-2705 or firstname.lastname@example.org.