The family of a man believed to have been attacked by a shark off the South Australian coast have mourned his "suspected death". Police were alerted after 32-year-old Duncan Craw, from regional Victoria, went missing in waters off Port MacDonnell in South Australia's lower south-east just before 5pm on Thursday. A torn wetsuit led them to believe the man had been attacked by a shark that had been spotted in the area. Duncan Craw is believed to have been killed in a shark attack off the South Australian coast.(Supplied) "It's impossible to adequately describe our grief and shock," Mr Craw's family said in a statement.