A body was found floating in the water near Copiague in Suffolk County Sunday, authorities said.
The man's body was found at Great South Bay by a boater, police said.
The man, identified as Joseph Unger, 57, of Amityville, was pronounced dead when transported to Tanner Park, police said.
An empty clamming boat was found nearby, police said.
The county medical examiner will determine the cause of death.
The investigation is ongoing.
Detectives are asking anyone with additional information to call the Homicide Squad at 631-852-6392.