the men were part of a group of five divers from the east coast and san francisco .
ten friends , including the dead men , had rented a house on caspar cove 160 miles north of san francisco to hunt for abalone , a rare and expensive mollusk that is prized as a delicacy .
the santa rosa press democrat reports that the accident in mendocino county is the deadliest single incident involving abalone divers in recent memory that