A mayday call was received from the dive boat Spectre about 10:15 a.m., indicating the woman, whose name was not released, had come to the surface unconscious after about 15 minutes of diving, said Coast Guard spokesman Adam Eggers.
A crew member on board the vessel, which is based out of Ventura Harbor, immediately began administering CPR, while an MH-65 Dolphin helicopter from Air Station Los Angeles and a 41-foot utility boat from Station Channel Islands Harbor were dispatched to the scene, Eggers said.
A Ventura County sheriff‘s helicopter arrived on scene, and lowered a paramedic onboard to continuing administering CPR, Eggers said.
However, after nearly an hour of trying — and several attempts to restart the patient’s heart with an electronic defibrillator — the woman was declared dead, Eggers said.
The Coast Guard brought the woman’s body and her husband back to shore, where they were met by members of the Ventura County Medical Examiner’s Office, Eggers said.