An associate professor in the biology department died after a scuba diving incident off the beach of the university’s Marine Science Center in Nahant on Friday.

Four divers from the Marine Science Center, including two students, exited the water after the dive and saw Charles Ellis Jr. sitting still in 2 to 3 feet of water, said Nahant Police Lieutenant Thomas Hutton.

“According to eyewitnesses, it looked like he was taking off his fins,” he said. “Then they found him face down in the water, not breathing.”

They pulled his body to shore and performed CPR on him while waiting for police and fire units to respond, Hutton said. He was taken to Salem Hospital, where he was pronounced dead the next day. He was 64.

Since the cause of death was not clear, an autopsy was performed over the weekend, Hutton said. The medical examiner’s office could not be contacted as of press time.

The campus reacted to Ellis’ death yesterday as Dean of Arts and Sciences James Stellar issued a release.

“We all miss you, Charlie,” Stellar wrote. “You were a great friend to everyone who knew you.”

Click to read the News’ obituary for Charles Ellis Jr.